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![Christophe JAILLET](/assets/img/avatar_default.png)
The devm_clk_get_enabled() helper: - calls devm_clk_get() - calls clk_prepare_enable() and registers what is needed in order to call clk_disable_unprepare() when needed, as a managed resource. This simplifies the code and avoids the need of a dedicated function used with devm_add_action_or_reset(). Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/1f8d1ce1e6a63c507a291aea624b1337326cc563.1672483996.git.christophe.jaillet@wanadoo.fr Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
291 lines
8.2 KiB
C
291 lines
8.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Imagination Technologies PowerDown Controller Watchdog Timer.
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*
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* Copyright (c) 2014 Imagination Technologies Ltd.
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*
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* Based on drivers/watchdog/sunxi_wdt.c Copyright (c) 2013 Carlo Caione
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* 2012 Henrik Nordstrom
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*
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* Notes
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* -----
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* The timeout value is rounded to the next power of two clock cycles.
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* This is configured using the PDC_WDT_CONFIG register, according to this
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* formula:
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*
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* timeout = 2^(delay + 1) clock cycles
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*
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* Where 'delay' is the value written in PDC_WDT_CONFIG register.
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*
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* Therefore, the hardware only allows to program watchdog timeouts, expressed
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* as a power of two number of watchdog clock cycles. The current implementation
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* guarantees that the actual watchdog timeout will be _at least_ the value
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* programmed in the imgpdg_wdt driver.
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*
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* The following table shows how the user-configured timeout relates
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* to the actual hardware timeout (watchdog clock @ 40000 Hz):
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*
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* input timeout | WD_DELAY | actual timeout
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* -----------------------------------
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* 10 | 18 | 13 seconds
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* 20 | 19 | 26 seconds
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* 30 | 20 | 52 seconds
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* 60 | 21 | 104 seconds
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*
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* Albeit coarse, this granularity would suffice most watchdog uses.
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* If the platform allows it, the user should be able to change the watchdog
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* clock rate and achieve a finer timeout granularity.
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*/
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/log2.h>
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#include <linux/module.h>
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#include <linux/mod_devicetable.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/watchdog.h>
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/* registers */
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#define PDC_WDT_SOFT_RESET 0x00
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#define PDC_WDT_CONFIG 0x04
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#define PDC_WDT_CONFIG_ENABLE BIT(31)
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#define PDC_WDT_CONFIG_DELAY_MASK 0x1f
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#define PDC_WDT_TICKLE1 0x08
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#define PDC_WDT_TICKLE1_MAGIC 0xabcd1234
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#define PDC_WDT_TICKLE2 0x0c
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#define PDC_WDT_TICKLE2_MAGIC 0x4321dcba
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#define PDC_WDT_TICKLE_STATUS_MASK 0x7
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#define PDC_WDT_TICKLE_STATUS_SHIFT 0
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#define PDC_WDT_TICKLE_STATUS_HRESET 0x0 /* Hard reset */
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#define PDC_WDT_TICKLE_STATUS_TIMEOUT 0x1 /* Timeout */
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#define PDC_WDT_TICKLE_STATUS_TICKLE 0x2 /* Tickled incorrectly */
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#define PDC_WDT_TICKLE_STATUS_SRESET 0x3 /* Soft reset */
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#define PDC_WDT_TICKLE_STATUS_USER 0x4 /* User reset */
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/* Timeout values are in seconds */
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#define PDC_WDT_MIN_TIMEOUT 1
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#define PDC_WDT_DEF_TIMEOUT 64
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static int heartbeat;
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module_param(heartbeat, int, 0);
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MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds "
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"(default=" __MODULE_STRING(PDC_WDT_DEF_TIMEOUT) ")");
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
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"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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struct pdc_wdt_dev {
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struct watchdog_device wdt_dev;
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struct clk *wdt_clk;
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struct clk *sys_clk;
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void __iomem *base;
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};
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static int pdc_wdt_keepalive(struct watchdog_device *wdt_dev)
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{
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struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
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writel(PDC_WDT_TICKLE1_MAGIC, wdt->base + PDC_WDT_TICKLE1);
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writel(PDC_WDT_TICKLE2_MAGIC, wdt->base + PDC_WDT_TICKLE2);
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return 0;
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}
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static int pdc_wdt_stop(struct watchdog_device *wdt_dev)
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{
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unsigned int val;
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struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
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val = readl(wdt->base + PDC_WDT_CONFIG);
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val &= ~PDC_WDT_CONFIG_ENABLE;
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writel(val, wdt->base + PDC_WDT_CONFIG);
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/* Must tickle to finish the stop */
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pdc_wdt_keepalive(wdt_dev);
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return 0;
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}
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static void __pdc_wdt_set_timeout(struct pdc_wdt_dev *wdt)
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{
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unsigned long clk_rate = clk_get_rate(wdt->wdt_clk);
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unsigned int val;
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val = readl(wdt->base + PDC_WDT_CONFIG) & ~PDC_WDT_CONFIG_DELAY_MASK;
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val |= order_base_2(wdt->wdt_dev.timeout * clk_rate) - 1;
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writel(val, wdt->base + PDC_WDT_CONFIG);
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}
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static int pdc_wdt_set_timeout(struct watchdog_device *wdt_dev,
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unsigned int new_timeout)
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{
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struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
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wdt->wdt_dev.timeout = new_timeout;
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__pdc_wdt_set_timeout(wdt);
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return 0;
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}
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/* Start the watchdog timer (delay should already be set) */
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static int pdc_wdt_start(struct watchdog_device *wdt_dev)
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{
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unsigned int val;
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struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
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__pdc_wdt_set_timeout(wdt);
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val = readl(wdt->base + PDC_WDT_CONFIG);
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val |= PDC_WDT_CONFIG_ENABLE;
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writel(val, wdt->base + PDC_WDT_CONFIG);
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return 0;
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}
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static int pdc_wdt_restart(struct watchdog_device *wdt_dev,
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unsigned long action, void *data)
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{
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struct pdc_wdt_dev *wdt = watchdog_get_drvdata(wdt_dev);
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/* Assert SOFT_RESET */
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writel(0x1, wdt->base + PDC_WDT_SOFT_RESET);
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return 0;
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}
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static const struct watchdog_info pdc_wdt_info = {
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.identity = "IMG PDC Watchdog",
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.options = WDIOF_SETTIMEOUT |
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WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE,
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};
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static const struct watchdog_ops pdc_wdt_ops = {
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.owner = THIS_MODULE,
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.start = pdc_wdt_start,
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.stop = pdc_wdt_stop,
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.ping = pdc_wdt_keepalive,
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.set_timeout = pdc_wdt_set_timeout,
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.restart = pdc_wdt_restart,
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};
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static int pdc_wdt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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u64 div;
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int val;
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unsigned long clk_rate;
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struct pdc_wdt_dev *pdc_wdt;
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pdc_wdt = devm_kzalloc(dev, sizeof(*pdc_wdt), GFP_KERNEL);
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if (!pdc_wdt)
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return -ENOMEM;
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pdc_wdt->base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(pdc_wdt->base))
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return PTR_ERR(pdc_wdt->base);
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pdc_wdt->sys_clk = devm_clk_get_enabled(dev, "sys");
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if (IS_ERR(pdc_wdt->sys_clk)) {
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dev_err(dev, "failed to get the sys clock\n");
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return PTR_ERR(pdc_wdt->sys_clk);
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}
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pdc_wdt->wdt_clk = devm_clk_get_enabled(dev, "wdt");
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if (IS_ERR(pdc_wdt->wdt_clk)) {
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dev_err(dev, "failed to get the wdt clock\n");
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return PTR_ERR(pdc_wdt->wdt_clk);
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}
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/* We use the clock rate to calculate the max timeout */
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clk_rate = clk_get_rate(pdc_wdt->wdt_clk);
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if (clk_rate == 0) {
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dev_err(dev, "failed to get clock rate\n");
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return -EINVAL;
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}
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if (order_base_2(clk_rate) > PDC_WDT_CONFIG_DELAY_MASK + 1) {
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dev_err(dev, "invalid clock rate\n");
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return -EINVAL;
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}
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if (order_base_2(clk_rate) == 0)
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pdc_wdt->wdt_dev.min_timeout = PDC_WDT_MIN_TIMEOUT + 1;
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else
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pdc_wdt->wdt_dev.min_timeout = PDC_WDT_MIN_TIMEOUT;
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pdc_wdt->wdt_dev.info = &pdc_wdt_info;
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pdc_wdt->wdt_dev.ops = &pdc_wdt_ops;
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div = 1ULL << (PDC_WDT_CONFIG_DELAY_MASK + 1);
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do_div(div, clk_rate);
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pdc_wdt->wdt_dev.max_timeout = div;
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pdc_wdt->wdt_dev.timeout = PDC_WDT_DEF_TIMEOUT;
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pdc_wdt->wdt_dev.parent = dev;
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watchdog_set_drvdata(&pdc_wdt->wdt_dev, pdc_wdt);
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watchdog_init_timeout(&pdc_wdt->wdt_dev, heartbeat, dev);
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pdc_wdt_stop(&pdc_wdt->wdt_dev);
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/* Find what caused the last reset */
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val = readl(pdc_wdt->base + PDC_WDT_TICKLE1);
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val = (val & PDC_WDT_TICKLE_STATUS_MASK) >> PDC_WDT_TICKLE_STATUS_SHIFT;
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switch (val) {
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case PDC_WDT_TICKLE_STATUS_TICKLE:
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case PDC_WDT_TICKLE_STATUS_TIMEOUT:
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pdc_wdt->wdt_dev.bootstatus |= WDIOF_CARDRESET;
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dev_info(dev, "watchdog module last reset due to timeout\n");
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break;
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case PDC_WDT_TICKLE_STATUS_HRESET:
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dev_info(dev,
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"watchdog module last reset due to hard reset\n");
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break;
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case PDC_WDT_TICKLE_STATUS_SRESET:
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dev_info(dev,
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"watchdog module last reset due to soft reset\n");
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break;
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case PDC_WDT_TICKLE_STATUS_USER:
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dev_info(dev,
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"watchdog module last reset due to user reset\n");
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break;
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default:
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dev_info(dev, "contains an illegal status code (%08x)\n", val);
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break;
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}
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watchdog_set_nowayout(&pdc_wdt->wdt_dev, nowayout);
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watchdog_set_restart_priority(&pdc_wdt->wdt_dev, 128);
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platform_set_drvdata(pdev, pdc_wdt);
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watchdog_stop_on_reboot(&pdc_wdt->wdt_dev);
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watchdog_stop_on_unregister(&pdc_wdt->wdt_dev);
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return devm_watchdog_register_device(dev, &pdc_wdt->wdt_dev);
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}
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static const struct of_device_id pdc_wdt_match[] = {
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{ .compatible = "img,pdc-wdt" },
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{}
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};
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MODULE_DEVICE_TABLE(of, pdc_wdt_match);
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static struct platform_driver pdc_wdt_driver = {
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.driver = {
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.name = "imgpdc-wdt",
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.of_match_table = pdc_wdt_match,
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},
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.probe = pdc_wdt_probe,
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};
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module_platform_driver(pdc_wdt_driver);
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MODULE_AUTHOR("Jude Abraham <Jude.Abraham@imgtec.com>");
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MODULE_AUTHOR("Naidu Tellapati <Naidu.Tellapati@imgtec.com>");
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MODULE_DESCRIPTION("Imagination Technologies PDC Watchdog Timer Driver");
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MODULE_LICENSE("GPL v2");
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