| /* |
| * Copyright 2010-2011 Picochip Ltd., Jamie Iles |
| * http://www.picochip.com |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| * 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. |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/bitops.h> |
| #include <linux/clk.h> |
| #include <linux/delay.h> |
| #include <linux/err.h> |
| #include <linux/io.h> |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/moduleparam.h> |
| #include <linux/of.h> |
| #include <linux/pm.h> |
| #include <linux/platform_device.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 |
| |
| /* The maximum TOP (timeout period) value that can be set in the watchdog. */ |
| #define DW_WDT_MAX_TOP 15 |
| |
| #define DW_WDT_DEFAULT_SECONDS 30 |
| |
| 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) ")"); |
| |
| struct dw_wdt { |
| void __iomem *regs; |
| struct clk *clk; |
| unsigned long rate; |
| struct watchdog_device wdd; |
| struct reset_control *rst; |
| }; |
| |
| #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; |
| } |
| |
| static inline int dw_wdt_top_in_seconds(struct dw_wdt *dw_wdt, unsigned top) |
| { |
| /* |
| * There are 16 possible timeout values in 0..15 where the number of |
| * cycles is 2 ^ (16 + i) and the watchdog counts down. |
| */ |
| return (1U << (16 + top)) / dw_wdt->rate; |
| } |
| |
| static int dw_wdt_get_top(struct dw_wdt *dw_wdt) |
| { |
| int top = readl(dw_wdt->regs + WDOG_TIMEOUT_RANGE_REG_OFFSET) & 0xF; |
| |
| return dw_wdt_top_in_seconds(dw_wdt, top); |
| } |
| |
| 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); |
| int i, top_val = DW_WDT_MAX_TOP; |
| |
| /* |
| * Iterate over the timeout values until we find the closest match. We |
| * always look for >=. |
| */ |
| for (i = 0; i <= DW_WDT_MAX_TOP; ++i) |
| if (dw_wdt_top_in_seconds(dw_wdt, i) >= top_s) { |
| top_val = i; |
| break; |
| } |
| |
| /* |
| * 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); |
| |
| wdd->timeout = dw_wdt_top_in_seconds(dw_wdt, top_val); |
| |
| return 0; |
| } |
| |
| static void dw_wdt_arm_system_reset(struct dw_wdt *dw_wdt) |
| { |
| u32 val = readl(dw_wdt->regs + WDOG_CONTROL_REG_OFFSET); |
| |
| /* Disable interrupt mode; always perform system reset. */ |
| 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_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); |
| 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); |
| |
| return readl(dw_wdt->regs + WDOG_CURRENT_COUNT_REG_OFFSET) / |
| dw_wdt->rate; |
| } |
| |
| static const struct watchdog_info dw_wdt_ident = { |
| .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | |
| 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, |
| .get_timeleft = dw_wdt_get_timeleft, |
| .restart = dw_wdt_restart, |
| }; |
| |
| #ifdef CONFIG_PM_SLEEP |
| static int dw_wdt_suspend(struct device *dev) |
| { |
| struct dw_wdt *dw_wdt = dev_get_drvdata(dev); |
| |
| 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; |
| |
| 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); |
| |
| static int dw_wdt_drv_probe(struct platform_device *pdev) |
| { |
| struct device *dev = &pdev->dev; |
| struct watchdog_device *wdd; |
| struct dw_wdt *dw_wdt; |
| struct resource *mem; |
| int ret; |
| |
| dw_wdt = devm_kzalloc(dev, sizeof(*dw_wdt), GFP_KERNEL); |
| if (!dw_wdt) |
| return -ENOMEM; |
| |
| mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| dw_wdt->regs = devm_ioremap_resource(dev, mem); |
| if (IS_ERR(dw_wdt->regs)) |
| return PTR_ERR(dw_wdt->regs); |
| |
| 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; |
| } |
| |
| 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_clk; |
| } |
| |
| reset_control_deassert(dw_wdt->rst); |
| |
| wdd = &dw_wdt->wdd; |
| wdd->info = &dw_wdt_ident; |
| wdd->ops = &dw_wdt_ops; |
| wdd->min_timeout = 1; |
| wdd->max_hw_heartbeat_ms = |
| dw_wdt_top_in_seconds(dw_wdt, DW_WDT_MAX_TOP) * 1000; |
| 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)) { |
| wdd->timeout = dw_wdt_get_top(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_clk; |
| |
| return 0; |
| |
| 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); |
| |
| watchdog_unregister_device(&dw_wdt->wdd); |
| reset_control_assert(dw_wdt->rst); |
| 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"); |