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![Wolfram Sang](/assets/img/avatar_default.png)
The core will print out details now. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
240 lines
5.1 KiB
C
240 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* PIC32 deadman timer driver
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*
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* Purna Chandra Mandal <purna.mandal@microchip.com>
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* Copyright (c) 2016, Microchip Technology Inc.
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*/
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#include <linux/clk.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/pm.h>
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#include <linux/watchdog.h>
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#include <asm/mach-pic32/pic32.h>
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/* Deadman Timer Regs */
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#define DMTCON_REG 0x00
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#define DMTPRECLR_REG 0x10
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#define DMTCLR_REG 0x20
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#define DMTSTAT_REG 0x30
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#define DMTCNT_REG 0x40
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#define DMTPSCNT_REG 0x60
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#define DMTPSINTV_REG 0x70
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/* Deadman Timer Regs fields */
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#define DMT_ON BIT(15)
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#define DMT_STEP1_KEY BIT(6)
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#define DMT_STEP2_KEY BIT(3)
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#define DMTSTAT_WINOPN BIT(0)
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#define DMTSTAT_EVENT BIT(5)
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#define DMTSTAT_BAD2 BIT(6)
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#define DMTSTAT_BAD1 BIT(7)
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/* Reset Control Register fields for watchdog */
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#define RESETCON_DMT_TIMEOUT BIT(5)
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struct pic32_dmt {
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void __iomem *regs;
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struct clk *clk;
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};
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static inline void dmt_enable(struct pic32_dmt *dmt)
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{
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writel(DMT_ON, PIC32_SET(dmt->regs + DMTCON_REG));
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}
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static inline void dmt_disable(struct pic32_dmt *dmt)
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{
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writel(DMT_ON, PIC32_CLR(dmt->regs + DMTCON_REG));
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/*
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* Cannot touch registers in the CPU cycle following clearing the
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* ON bit.
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*/
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nop();
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}
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static inline int dmt_bad_status(struct pic32_dmt *dmt)
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{
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u32 val;
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val = readl(dmt->regs + DMTSTAT_REG);
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val &= (DMTSTAT_BAD1 | DMTSTAT_BAD2 | DMTSTAT_EVENT);
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if (val)
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return -EAGAIN;
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return 0;
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}
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static inline int dmt_keepalive(struct pic32_dmt *dmt)
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{
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u32 v;
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u32 timeout = 500;
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/* set pre-clear key */
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writel(DMT_STEP1_KEY << 8, dmt->regs + DMTPRECLR_REG);
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/* wait for DMT window to open */
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while (--timeout) {
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v = readl(dmt->regs + DMTSTAT_REG) & DMTSTAT_WINOPN;
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if (v == DMTSTAT_WINOPN)
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break;
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}
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/* apply key2 */
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writel(DMT_STEP2_KEY, dmt->regs + DMTCLR_REG);
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/* check whether keys are latched correctly */
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return dmt_bad_status(dmt);
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}
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static inline u32 pic32_dmt_get_timeout_secs(struct pic32_dmt *dmt)
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{
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unsigned long rate;
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rate = clk_get_rate(dmt->clk);
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if (rate)
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return readl(dmt->regs + DMTPSCNT_REG) / rate;
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return 0;
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}
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static inline u32 pic32_dmt_bootstatus(struct pic32_dmt *dmt)
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{
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u32 v;
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void __iomem *rst_base;
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rst_base = ioremap(PIC32_BASE_RESET, 0x10);
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if (!rst_base)
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return 0;
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v = readl(rst_base);
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writel(RESETCON_DMT_TIMEOUT, PIC32_CLR(rst_base));
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iounmap(rst_base);
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return v & RESETCON_DMT_TIMEOUT;
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}
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static int pic32_dmt_start(struct watchdog_device *wdd)
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{
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struct pic32_dmt *dmt = watchdog_get_drvdata(wdd);
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dmt_enable(dmt);
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return dmt_keepalive(dmt);
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}
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static int pic32_dmt_stop(struct watchdog_device *wdd)
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{
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struct pic32_dmt *dmt = watchdog_get_drvdata(wdd);
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dmt_disable(dmt);
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return 0;
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}
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static int pic32_dmt_ping(struct watchdog_device *wdd)
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{
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struct pic32_dmt *dmt = watchdog_get_drvdata(wdd);
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return dmt_keepalive(dmt);
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}
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static const struct watchdog_ops pic32_dmt_fops = {
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.owner = THIS_MODULE,
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.start = pic32_dmt_start,
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.stop = pic32_dmt_stop,
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.ping = pic32_dmt_ping,
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};
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static const struct watchdog_info pic32_dmt_ident = {
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.options = WDIOF_KEEPALIVEPING |
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WDIOF_MAGICCLOSE,
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.identity = "PIC32 Deadman Timer",
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};
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static struct watchdog_device pic32_dmt_wdd = {
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.info = &pic32_dmt_ident,
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.ops = &pic32_dmt_fops,
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};
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static void pic32_clk_disable_unprepare(void *data)
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{
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clk_disable_unprepare(data);
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}
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static int pic32_dmt_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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int ret;
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struct pic32_dmt *dmt;
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struct watchdog_device *wdd = &pic32_dmt_wdd;
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dmt = devm_kzalloc(dev, sizeof(*dmt), GFP_KERNEL);
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if (!dmt)
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return -ENOMEM;
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dmt->regs = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(dmt->regs))
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return PTR_ERR(dmt->regs);
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dmt->clk = devm_clk_get(dev, NULL);
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if (IS_ERR(dmt->clk)) {
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dev_err(dev, "clk not found\n");
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return PTR_ERR(dmt->clk);
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}
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ret = clk_prepare_enable(dmt->clk);
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if (ret)
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return ret;
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ret = devm_add_action_or_reset(dev, pic32_clk_disable_unprepare,
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dmt->clk);
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if (ret)
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return ret;
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wdd->timeout = pic32_dmt_get_timeout_secs(dmt);
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if (!wdd->timeout) {
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dev_err(dev, "failed to read watchdog register timeout\n");
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return -EINVAL;
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}
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dev_info(dev, "timeout %d\n", wdd->timeout);
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wdd->bootstatus = pic32_dmt_bootstatus(dmt) ? WDIOF_CARDRESET : 0;
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watchdog_set_nowayout(wdd, WATCHDOG_NOWAYOUT);
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watchdog_set_drvdata(wdd, dmt);
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ret = devm_watchdog_register_device(dev, wdd);
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if (ret)
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return ret;
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platform_set_drvdata(pdev, wdd);
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return 0;
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}
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static const struct of_device_id pic32_dmt_of_ids[] = {
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{ .compatible = "microchip,pic32mzda-dmt",},
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{ /* sentinel */ }
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};
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MODULE_DEVICE_TABLE(of, pic32_dmt_of_ids);
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static struct platform_driver pic32_dmt_driver = {
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.probe = pic32_dmt_probe,
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.driver = {
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.name = "pic32-dmt",
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.of_match_table = of_match_ptr(pic32_dmt_of_ids),
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}
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};
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module_platform_driver(pic32_dmt_driver);
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MODULE_AUTHOR("Purna Chandra Mandal <purna.mandal@microchip.com>");
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MODULE_DESCRIPTION("Microchip PIC32 DMT Driver");
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MODULE_LICENSE("GPL");
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