linux-stable/drivers/watchdog/dw_wdt.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2010-2011 Picochip Ltd., Jamie Iles
* https://www.picochip.com
*
* This file implements a driver for the Synopsys DesignWare watchdog device
* in the many subsystems. The watchdog has 16 different timeout periods
* and these are a function of the input clock frequency.
*
* The DesignWare watchdog cannot be stopped once it has been started so we
* do not implement a stop function. The watchdog core will continue to send
* heartbeat requests after the watchdog device has been closed.
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/limits.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/reset.h>
#include <linux/watchdog.h>
#define WDOG_CONTROL_REG_OFFSET 0x00
#define WDOG_CONTROL_REG_WDT_EN_MASK 0x01
#define WDOG_CONTROL_REG_RESP_MODE_MASK 0x02
#define WDOG_TIMEOUT_RANGE_REG_OFFSET 0x04
#define WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT 4
#define WDOG_CURRENT_COUNT_REG_OFFSET 0x08
#define WDOG_COUNTER_RESTART_REG_OFFSET 0x0c
#define WDOG_COUNTER_RESTART_KICK_VALUE 0x76
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
#define WDOG_INTERRUPT_STATUS_REG_OFFSET 0x10
#define WDOG_INTERRUPT_CLEAR_REG_OFFSET 0x14
#define WDOG_COMP_PARAMS_5_REG_OFFSET 0xe4
#define WDOG_COMP_PARAMS_4_REG_OFFSET 0xe8
#define WDOG_COMP_PARAMS_3_REG_OFFSET 0xec
#define WDOG_COMP_PARAMS_2_REG_OFFSET 0xf0
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
#define WDOG_COMP_PARAMS_1_REG_OFFSET 0xf4
#define WDOG_COMP_PARAMS_1_USE_FIX_TOP BIT(6)
#define WDOG_COMP_VERSION_REG_OFFSET 0xf8
#define WDOG_COMP_TYPE_REG_OFFSET 0xfc
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
/* There are sixteen TOPs (timeout periods) that can be set in the watchdog. */
#define DW_WDT_NUM_TOPS 16
#define DW_WDT_FIX_TOP(_idx) (1U << (16 + _idx))
#define DW_WDT_DEFAULT_SECONDS 30
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
static const u32 dw_wdt_fix_tops[DW_WDT_NUM_TOPS] = {
DW_WDT_FIX_TOP(0), DW_WDT_FIX_TOP(1), DW_WDT_FIX_TOP(2),
DW_WDT_FIX_TOP(3), DW_WDT_FIX_TOP(4), DW_WDT_FIX_TOP(5),
DW_WDT_FIX_TOP(6), DW_WDT_FIX_TOP(7), DW_WDT_FIX_TOP(8),
DW_WDT_FIX_TOP(9), DW_WDT_FIX_TOP(10), DW_WDT_FIX_TOP(11),
DW_WDT_FIX_TOP(12), DW_WDT_FIX_TOP(13), DW_WDT_FIX_TOP(14),
DW_WDT_FIX_TOP(15)
};
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
enum dw_wdt_rmod {
DW_WDT_RMOD_RESET = 1,
DW_WDT_RMOD_IRQ = 2
};
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
struct dw_wdt_timeout {
u32 top_val;
unsigned int sec;
unsigned int msec;
};
struct dw_wdt {
void __iomem *regs;
struct clk *clk;
struct clk *pclk;
unsigned long rate;
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
enum dw_wdt_rmod rmod;
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
struct dw_wdt_timeout timeouts[DW_WDT_NUM_TOPS];
struct watchdog_device wdd;
struct reset_control *rst;
/* Save/restore */
u32 control;
u32 timeout;
#ifdef CONFIG_DEBUG_FS
struct dentry *dbgfs_dir;
#endif
};
#define to_dw_wdt(wdd) container_of(wdd, struct dw_wdt, wdd)
static inline int dw_wdt_is_enabled(struct dw_wdt *dw_wdt)
{
return readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET) &
WDOG_CONTROL_REG_WDT_EN_MASK;
}
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
static void dw_wdt_update_mode(struct dw_wdt *dw_wdt, enum dw_wdt_rmod rmod)
{
u32 val;
val = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
if (rmod == DW_WDT_RMOD_IRQ)
val |= WDOG_CONTROL_REG_RESP_MODE_MASK;
else
val &= ~WDOG_CONTROL_REG_RESP_MODE_MASK;
writel(val, dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
dw_wdt->rmod = rmod;
}
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
static unsigned int dw_wdt_find_best_top(struct dw_wdt *dw_wdt,
unsigned int timeout, u32 *top_val)
{
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
int idx;
/*
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
* Find a TOP with timeout greater or equal to the requested number.
* Note we'll select a TOP with maximum timeout if the requested
* timeout couldn't be reached.
*/
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
for (idx = 0; idx < DW_WDT_NUM_TOPS; ++idx) {
if (dw_wdt->timeouts[idx].sec >= timeout)
break;
}
if (idx == DW_WDT_NUM_TOPS)
--idx;
*top_val = dw_wdt->timeouts[idx].top_val;
return dw_wdt->timeouts[idx].sec;
}
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
static unsigned int dw_wdt_get_min_timeout(struct dw_wdt *dw_wdt)
{
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
int idx;
/*
* We'll find a timeout greater or equal to one second anyway because
* the driver probe would have failed if there was none.
*/
for (idx = 0; idx < DW_WDT_NUM_TOPS; ++idx) {
if (dw_wdt->timeouts[idx].sec)
break;
}
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
return dw_wdt->timeouts[idx].sec;
}
static unsigned int dw_wdt_get_max_timeout_ms(struct dw_wdt *dw_wdt)
{
struct dw_wdt_timeout *timeout = &dw_wdt->timeouts[DW_WDT_NUM_TOPS - 1];
u64 msec;
msec = (u64)timeout->sec * MSEC_PER_SEC + timeout->msec;
return msec < UINT_MAX ? msec : UINT_MAX;
}
static unsigned int dw_wdt_get_timeout(struct dw_wdt *dw_wdt)
{
int top_val = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET) & 0xF;
int idx;
for (idx = 0; idx < DW_WDT_NUM_TOPS; ++idx) {
if (dw_wdt->timeouts[idx].top_val == top_val)
break;
}
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
/*
* In IRQ mode due to the two stages counter, the actual timeout is
* twice greater than the TOP setting.
*/
return dw_wdt->timeouts[idx].sec * dw_wdt->rmod;
}
static int dw_wdt_ping(struct watchdog_device *wdd)
{
struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
writel(WDOG_COUNTER_RESTART_KICK_VALUE, dw_wdt->regs +
WDOG_COUNTER_RESTART_REG_OFFSET);
return 0;
}
static int dw_wdt_set_timeout(struct watchdog_device *wdd, unsigned int top_s)
{
struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
unsigned int timeout;
u32 top_val;
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
/*
* Note IRQ mode being enabled means having a non-zero pre-timeout
* setup. In this case we try to find a TOP as close to the half of the
* requested timeout as possible since DW Watchdog IRQ mode is designed
* in two stages way - first timeout rises the pre-timeout interrupt,
* second timeout performs the system reset. So basically the effective
* watchdog-caused reset happens after two watchdog TOPs elapsed.
*/
timeout = dw_wdt_find_best_top(dw_wdt, DIV_ROUND_UP(top_s, dw_wdt->rmod),
&top_val);
if (dw_wdt->rmod == DW_WDT_RMOD_IRQ)
wdd->pretimeout = timeout;
else
wdd->pretimeout = 0;
/*
* Set the new value in the watchdog. Some versions of dw_wdt
* have have TOPINIT in the TIMEOUT_RANGE register (as per
* CP_WDT_DUAL_TOP in WDT_COMP_PARAMS_1). On those we
* effectively get a pat of the watchdog right here.
*/
writel(top_val | top_val << WDOG_TIMEOUT_RANGE_TOPINIT_SHIFT,
dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
/* Kick new TOP value into the watchdog counter if activated. */
if (watchdog_active(wdd))
dw_wdt_ping(wdd);
/*
* In case users set bigger timeout value than HW can support,
* kernel(watchdog_dev.c) helps to feed watchdog before
* wdd->max_hw_heartbeat_ms
*/
if (top_s * 1000 <= wdd->max_hw_heartbeat_ms)
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
wdd->timeout = timeout * dw_wdt->rmod;
else
wdd->timeout = top_s;
return 0;
}
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
static int dw_wdt_set_pretimeout(struct watchdog_device *wdd, unsigned int req)
{
struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
/*
* We ignore actual value of the timeout passed from user-space
* using it as a flag whether the pretimeout functionality is intended
* to be activated.
*/
dw_wdt_update_mode(dw_wdt, req ? DW_WDT_RMOD_IRQ : DW_WDT_RMOD_RESET);
dw_wdt_set_timeout(wdd, wdd->timeout);
return 0;
}
static void dw_wdt_arm_system_reset(struct dw_wdt *dw_wdt)
{
u32 val = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
/* Disable/enable interrupt mode depending on the RMOD flag. */
if (dw_wdt->rmod == DW_WDT_RMOD_IRQ)
val |= WDOG_CONTROL_REG_RESP_MODE_MASK;
else
val &= ~WDOG_CONTROL_REG_RESP_MODE_MASK;
/* Enable watchdog. */
val |= WDOG_CONTROL_REG_WDT_EN_MASK;
writel(val, dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
}
static int dw_wdt_start(struct watchdog_device *wdd)
{
struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
dw_wdt_set_timeout(wdd, wdd->timeout);
dw_wdt_ping(&dw_wdt->wdd);
dw_wdt_arm_system_reset(dw_wdt);
return 0;
}
static int dw_wdt_stop(struct watchdog_device *wdd)
{
struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
if (!dw_wdt->rst) {
set_bit(WDOG_HW_RUNNING, &wdd->status);
return 0;
}
reset_control_assert(dw_wdt->rst);
reset_control_deassert(dw_wdt->rst);
return 0;
}
static int dw_wdt_restart(struct watchdog_device *wdd,
unsigned long action, void *data)
{
struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
writel(0, dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
dw_wdt_update_mode(dw_wdt, DW_WDT_RMOD_RESET);
if (dw_wdt_is_enabled(dw_wdt))
writel(WDOG_COUNTER_RESTART_KICK_VALUE,
dw_wdt->regs + WDOG_COUNTER_RESTART_REG_OFFSET);
else
dw_wdt_arm_system_reset(dw_wdt);
/* wait for reset to assert... */
mdelay(500);
return 0;
}
static unsigned int dw_wdt_get_timeleft(struct watchdog_device *wdd)
{
struct dw_wdt *dw_wdt = to_dw_wdt(wdd);
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
unsigned int sec;
u32 val;
val = readl(dw_wdt->regs + WDOG_CURRENT_COUNT_REG_OFFSET);
sec = val / dw_wdt->rate;
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
if (dw_wdt->rmod == DW_WDT_RMOD_IRQ) {
val = readl(dw_wdt->regs + WDOG_INTERRUPT_STATUS_REG_OFFSET);
if (!val)
sec += wdd->pretimeout;
}
return sec;
}
static const struct watchdog_info dw_wdt_ident = {
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
WDIOF_MAGICCLOSE,
.identity = "Synopsys DesignWare Watchdog",
};
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
static const struct watchdog_info dw_wdt_pt_ident = {
.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT |
WDIOF_PRETIMEOUT | WDIOF_MAGICCLOSE,
.identity = "Synopsys DesignWare Watchdog",
};
static const struct watchdog_ops dw_wdt_ops = {
.owner = THIS_MODULE,
.start = dw_wdt_start,
.stop = dw_wdt_stop,
.ping = dw_wdt_ping,
.set_timeout = dw_wdt_set_timeout,
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
.set_pretimeout = dw_wdt_set_pretimeout,
.get_timeleft = dw_wdt_get_timeleft,
.restart = dw_wdt_restart,
};
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
static irqreturn_t dw_wdt_irq(int irq, void *devid)
{
struct dw_wdt *dw_wdt = devid;
u32 val;
/*
* We don't clear the IRQ status. It's supposed to be done by the
* following ping operations.
*/
val = readl(dw_wdt->regs + WDOG_INTERRUPT_STATUS_REG_OFFSET);
if (!val)
return IRQ_NONE;
watchdog_notify_pretimeout(&dw_wdt->wdd);
return IRQ_HANDLED;
}
#ifdef CONFIG_PM_SLEEP
static int dw_wdt_suspend(struct device *dev)
{
struct dw_wdt *dw_wdt = dev_get_drvdata(dev);
dw_wdt->control = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
dw_wdt->timeout = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
clk_disable_unprepare(dw_wdt->pclk);
clk_disable_unprepare(dw_wdt->clk);
return 0;
}
static int dw_wdt_resume(struct device *dev)
{
struct dw_wdt *dw_wdt = dev_get_drvdata(dev);
int err = clk_prepare_enable(dw_wdt->clk);
if (err)
return err;
err = clk_prepare_enable(dw_wdt->pclk);
if (err) {
clk_disable_unprepare(dw_wdt->clk);
return err;
}
writel(dw_wdt->timeout, dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET);
writel(dw_wdt->control, dw_wdt->regs + WDOG_CONTROL_REG_OFFSET);
dw_wdt_ping(&dw_wdt->wdd);
return 0;
}
#endif /* CONFIG_PM_SLEEP */
static SIMPLE_DEV_PM_OPS(dw_wdt_pm_ops, dw_wdt_suspend, dw_wdt_resume);
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
/*
* In case if DW WDT IP core is synthesized with fixed TOP feature disabled the
* TOPs array can be arbitrary ordered with nearly any sixteen uint numbers
* depending on the system engineer imagination. The next method handles the
* passed TOPs array to pre-calculate the effective timeouts and to sort the
* TOP items out in the ascending order with respect to the timeouts.
*/
static void dw_wdt_handle_tops(struct dw_wdt *dw_wdt, const u32 *tops)
{
struct dw_wdt_timeout tout, *dst;
int val, tidx;
u64 msec;
/*
* We walk over the passed TOPs array and calculate corresponding
* timeouts in seconds and milliseconds. The milliseconds granularity
* is needed to distinguish the TOPs with very close timeouts and to
* set the watchdog max heartbeat setting further.
*/
for (val = 0; val < DW_WDT_NUM_TOPS; ++val) {
tout.top_val = val;
tout.sec = tops[val] / dw_wdt->rate;
msec = (u64)tops[val] * MSEC_PER_SEC;
do_div(msec, dw_wdt->rate);
tout.msec = msec - ((u64)tout.sec * MSEC_PER_SEC);
/*
* Find a suitable place for the current TOP in the timeouts
* array so that the list is remained in the ascending order.
*/
for (tidx = 0; tidx < val; ++tidx) {
dst = &dw_wdt->timeouts[tidx];
if (tout.sec > dst->sec || (tout.sec == dst->sec &&
tout.msec >= dst->msec))
continue;
else
swap(*dst, tout);
}
dw_wdt->timeouts[val] = tout;
}
}
static int dw_wdt_init_timeouts(struct dw_wdt *dw_wdt, struct device *dev)
{
u32 data, of_tops[DW_WDT_NUM_TOPS];
const u32 *tops;
int ret;
/*
* Retrieve custom or fixed counter values depending on the
* WDT_USE_FIX_TOP flag found in the component specific parameters
* #1 register.
*/
data = readl(dw_wdt->regs + WDOG_COMP_PARAMS_1_REG_OFFSET);
if (data & WDOG_COMP_PARAMS_1_USE_FIX_TOP) {
tops = dw_wdt_fix_tops;
} else {
ret = of_property_read_variable_u32_array(dev_of_node(dev),
"snps,watchdog-tops", of_tops, DW_WDT_NUM_TOPS,
DW_WDT_NUM_TOPS);
if (ret < 0) {
dev_warn(dev, "No valid TOPs array specified\n");
tops = dw_wdt_fix_tops;
} else {
tops = of_tops;
}
}
/* Convert the specified TOPs into an array of watchdog timeouts. */
dw_wdt_handle_tops(dw_wdt, tops);
if (!dw_wdt->timeouts[DW_WDT_NUM_TOPS - 1].sec) {
dev_err(dev, "No any valid TOP detected\n");
return -EINVAL;
}
return 0;
}
#ifdef CONFIG_DEBUG_FS
#define DW_WDT_DBGFS_REG(_name, _off) \
{ \
.name = _name, \
.offset = _off \
}
static const struct debugfs_reg32 dw_wdt_dbgfs_regs[] = {
DW_WDT_DBGFS_REG("cr", WDOG_CONTROL_REG_OFFSET),
DW_WDT_DBGFS_REG("torr", WDOG_TIMEOUT_RANGE_REG_OFFSET),
DW_WDT_DBGFS_REG("ccvr", WDOG_CURRENT_COUNT_REG_OFFSET),
DW_WDT_DBGFS_REG("crr", WDOG_COUNTER_RESTART_REG_OFFSET),
DW_WDT_DBGFS_REG("stat", WDOG_INTERRUPT_STATUS_REG_OFFSET),
DW_WDT_DBGFS_REG("param5", WDOG_COMP_PARAMS_5_REG_OFFSET),
DW_WDT_DBGFS_REG("param4", WDOG_COMP_PARAMS_4_REG_OFFSET),
DW_WDT_DBGFS_REG("param3", WDOG_COMP_PARAMS_3_REG_OFFSET),
DW_WDT_DBGFS_REG("param2", WDOG_COMP_PARAMS_2_REG_OFFSET),
DW_WDT_DBGFS_REG("param1", WDOG_COMP_PARAMS_1_REG_OFFSET),
DW_WDT_DBGFS_REG("version", WDOG_COMP_VERSION_REG_OFFSET),
DW_WDT_DBGFS_REG("type", WDOG_COMP_TYPE_REG_OFFSET)
};
static void dw_wdt_dbgfs_init(struct dw_wdt *dw_wdt)
{
struct device *dev = dw_wdt->wdd.parent;
struct debugfs_regset32 *regset;
regset = devm_kzalloc(dev, sizeof(*regset), GFP_KERNEL);
if (!regset)
return;
regset->regs = dw_wdt_dbgfs_regs;
regset->nregs = ARRAY_SIZE(dw_wdt_dbgfs_regs);
regset->base = dw_wdt->regs;
dw_wdt->dbgfs_dir = debugfs_create_dir(dev_name(dev), NULL);
debugfs_create_regset32("registers", 0444, dw_wdt->dbgfs_dir, regset);
}
static void dw_wdt_dbgfs_clear(struct dw_wdt *dw_wdt)
{
debugfs_remove_recursive(dw_wdt->dbgfs_dir);
}
#else /* !CONFIG_DEBUG_FS */
static void dw_wdt_dbgfs_init(struct dw_wdt *dw_wdt) {}
static void dw_wdt_dbgfs_clear(struct dw_wdt *dw_wdt) {}
#endif /* !CONFIG_DEBUG_FS */
static int dw_wdt_drv_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct watchdog_device *wdd;
struct dw_wdt *dw_wdt;
int ret;
dw_wdt = devm_kzalloc(dev, sizeof(*dw_wdt), GFP_KERNEL);
if (!dw_wdt)
return -ENOMEM;
watchdog: Convert to use devm_platform_ioremap_resource Use devm_platform_ioremap_resource to reduce source code size, improve readability, and reduce the likelyhood of bugs. The conversion was done automatically with coccinelle using the following semantic patch. @r@ identifier res, pdev; expression a; expression index; expression e; @@ <+... - res = platform_get_resource(pdev, IORESOURCE_MEM, index); - a = devm_ioremap_resource(e, res); + a = devm_platform_ioremap_resource(pdev, index); ...+> @depends on r@ identifier r.res; @@ - struct resource *res; ... when != res @@ identifier res, pdev; expression index; expression a; @@ - struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, index); - a = devm_ioremap_resource(&pdev->dev, res); + a = devm_platform_ioremap_resource(pdev, index); Cc: Joel Stanley <joel@jms.id.au> Cc: Nicolas Ferre <nicolas.ferre@microchip.com> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Baruch Siach <baruch@tkos.co.il> Cc: Keguang Zhang <keguang.zhang@gmail.com> Cc: Vladimir Zapolskiy <vz@mleia.com> Cc: Kevin Hilman <khilman@baylibre.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Avi Fishman <avifishman70@gmail.com> Cc: Nancy Yuen <yuenn@google.com> Cc: Brendan Higgins <brendanhiggins@google.com> Cc: Wan ZongShun <mcuos.com@gmail.com> Cc: Michal Simek <michal.simek@xilinx.com> Cc: Sylvain Lemieux <slemieux.tyco@gmail.com> Cc: Kukjin Kim <kgene@kernel.org> Cc: Barry Song <baohua@kernel.org> Cc: Orson Zhai <orsonzhai@gmail.com> Cc: Patrice Chotard <patrice.chotard@st.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Maxime Ripard <maxime.ripard@bootlin.com> Cc: Chen-Yu Tsai <wens@csie.org> Cc: Marc Gonzalez <marc.w.gonzalez@free.fr> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Shawn Guo <shawnguo@kernel.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Tested-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Joel Stanley <joel@jms.id.au> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Maxime Ripard <maxime.ripard@bootlin.com> Acked-by: Michal Simek <michal.simek@xilinx.com> (cadence/xilinx wdts) Acked-by: Thierry Reding <treding@nvidia.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Acked-by: Patrice Chotard <patrice.chotard@st.com> Acked-by: Vladimir Zapolskiy <vz@mleia.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2019-04-02 19:01:53 +00:00
dw_wdt->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(dw_wdt->regs))
return PTR_ERR(dw_wdt->regs);
/*
* Try to request the watchdog dedicated timer clock source. It must
* be supplied if asynchronous mode is enabled. Otherwise fallback
* to the common timer/bus clocks configuration, in which the very
* first found clock supply both timer and APB signals.
*/
dw_wdt->clk = devm_clk_get(dev, "tclk");
if (IS_ERR(dw_wdt->clk)) {
dw_wdt->clk = devm_clk_get(dev, NULL);
if (IS_ERR(dw_wdt->clk))
return PTR_ERR(dw_wdt->clk);
}
ret = clk_prepare_enable(dw_wdt->clk);
if (ret)
return ret;
dw_wdt->rate = clk_get_rate(dw_wdt->clk);
if (dw_wdt->rate == 0) {
ret = -EINVAL;
goto out_disable_clk;
}
/*
* Request APB clock if device is configured with async clocks mode.
* In this case both tclk and pclk clocks are supposed to be specified.
* Alas we can't know for sure whether async mode was really activated,
* so the pclk phandle reference is left optional. If it couldn't be
* found we consider the device configured in synchronous clocks mode.
*/
dw_wdt->pclk = devm_clk_get_optional(dev, "pclk");
if (IS_ERR(dw_wdt->pclk)) {
ret = PTR_ERR(dw_wdt->pclk);
goto out_disable_clk;
}
ret = clk_prepare_enable(dw_wdt->pclk);
if (ret)
goto out_disable_clk;
dw_wdt->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
if (IS_ERR(dw_wdt->rst)) {
ret = PTR_ERR(dw_wdt->rst);
goto out_disable_pclk;
}
watchdog: dw_wdt: Add pre-timeouts support DW Watchdog can rise an interrupt in case if IRQ request mode is enabled and timer reaches the zero value. In this case the IRQ lane is left pending until either the next watchdog kick event (watchdog restart) or until the WDT_EOI register is read or the device/system reset. This interface can be used to implement the pre-timeout functionality optionally provided by the Linux kernel watchdog devices. IRQ mode provides a two stages timeout interface. It means the IRQ is raised when the counter reaches zero, while the system reset occurs only after subsequent timeout if the timer restart is not performed. Due to this peculiarity the pre-timeout value is actually set to the achieved hardware timeout, while the real watchdog timeout is considered to be twice as much of it. This applies a significant limitation on the pre-timeout values, so current implementation supports either zero value, which disables the pre-timeout events, or non-zero values, which imply the pre-timeout to be at least half of the current watchdog timeout. Note that we ask the interrupt controller to detect the rising-edge pre-timeout interrupts to prevent the high-level-IRQs flood, since if the pre-timeout happens, the IRQ lane will be left pending until it's cleared by the timer restart. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:56 +00:00
/* Enable normal reset without pre-timeout by default. */
dw_wdt_update_mode(dw_wdt, DW_WDT_RMOD_RESET);
/*
* Pre-timeout IRQ is optional, since some hardware may lack support
* of it. Note we must request rising-edge IRQ, since the lane is left
* pending either until the next watchdog kick event or up to the
* system reset.
*/
ret = platform_get_irq_optional(pdev, 0);
if (ret > 0) {
ret = devm_request_irq(dev, ret, dw_wdt_irq,
IRQF_SHARED | IRQF_TRIGGER_RISING,
pdev->name, dw_wdt);
if (ret)
goto out_disable_pclk;
dw_wdt->wdd.info = &dw_wdt_pt_ident;
} else {
if (ret == -EPROBE_DEFER)
goto out_disable_pclk;
dw_wdt->wdd.info = &dw_wdt_ident;
}
reset_control_deassert(dw_wdt->rst);
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
ret = dw_wdt_init_timeouts(dw_wdt, dev);
if (ret)
goto out_disable_clk;
wdd = &dw_wdt->wdd;
wdd->ops = &dw_wdt_ops;
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
wdd->min_timeout = dw_wdt_get_min_timeout(dw_wdt);
wdd->max_hw_heartbeat_ms = dw_wdt_get_max_timeout_ms(dw_wdt);
wdd->parent = dev;
watchdog_set_drvdata(wdd, dw_wdt);
watchdog_set_nowayout(wdd, nowayout);
watchdog_init_timeout(wdd, 0, dev);
/*
* If the watchdog is already running, use its already configured
* timeout. Otherwise use the default or the value provided through
* devicetree.
*/
if (dw_wdt_is_enabled(dw_wdt)) {
watchdog: dw_wdt: Support devices with non-fixed TOP values In case if the DW Watchdog IP core is synthesised with WDT_USE_FIX_TOP == false, the TOP interval indexes make the device to load a custom periods to the counter. These periods are hardwired at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)]. Alas their values can't be detected at runtime and must be somehow supplied to the driver so one could properly determine the watchdog timeout intervals. For this purpose we suggest to have a vendor- specific dts property "snps,watchdog-tops" utilized, which would provide an array of sixteen counter values. At device probe stage they will be used to initialize the watchdog device timeouts determined from the array values and current clocks source rate. In order to have custom TOP values supported the driver must be altered in the following way. First of all the fixed-top values ready-to-use array must be determined for compatibility with currently supported devices, which were synthesised with WDT_USE_FIX_TOP == true. It will be used if either fixed TOP feature is detected being enabled or no custom TOPs are fetched from the device dt node. Secondly at the probe stage we must initialize an array of the watchdog timeouts corresponding to the detected TOPs list and the reference clock rate. For generality the procedure of initialization is designed in a way to support the TOPs array with no limitations on the items order or value. Finally the watchdog period search methods should be altered to support the new timeouts data structure. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rob Herring <robh+dt@kernel.org> Cc: linux-mips@vger.kernel.org Cc: devicetree@vger.kernel.org Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
2020-05-30 07:35:54 +00:00
wdd->timeout = dw_wdt_get_timeout(dw_wdt);
set_bit(WDOG_HW_RUNNING, &wdd->status);
} else {
wdd->timeout = DW_WDT_DEFAULT_SECONDS;
watchdog_init_timeout(wdd, 0, dev);
}
platform_set_drvdata(pdev, dw_wdt);
watchdog_set_restart_priority(wdd, 128);
ret = watchdog_register_device(wdd);
if (ret)
goto out_disable_pclk;
dw_wdt_dbgfs_init(dw_wdt);
return 0;
out_disable_pclk:
clk_disable_unprepare(dw_wdt->pclk);
out_disable_clk:
clk_disable_unprepare(dw_wdt->clk);
return ret;
}
static int dw_wdt_drv_remove(struct platform_device *pdev)
{
struct dw_wdt *dw_wdt = platform_get_drvdata(pdev);
dw_wdt_dbgfs_clear(dw_wdt);
watchdog_unregister_device(&dw_wdt->wdd);
reset_control_assert(dw_wdt->rst);
clk_disable_unprepare(dw_wdt->pclk);
clk_disable_unprepare(dw_wdt->clk);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id dw_wdt_of_match[] = {
{ .compatible = "snps,dw-wdt", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, dw_wdt_of_match);
#endif
static struct platform_driver dw_wdt_driver = {
.probe = dw_wdt_drv_probe,
.remove = dw_wdt_drv_remove,
.driver = {
.name = "dw_wdt",
.of_match_table = of_match_ptr(dw_wdt_of_match),
.pm = &dw_wdt_pm_ops,
},
};
module_platform_driver(dw_wdt_driver);
MODULE_AUTHOR("Jamie Iles");
MODULE_DESCRIPTION("Synopsys DesignWare Watchdog Driver");
MODULE_LICENSE("GPL");