diff options
author | Anson Huang <Anson.Huang@nxp.com> | 2020-09-22 13:15:23 +0800 |
---|---|---|
committer | Anson Huang <Anson.Huang@nxp.com> | 2020-09-22 16:38:14 +0800 |
commit | a24b70669962aae741cd764f37fd603988e6a2b1 (patch) | |
tree | cd2ac3b02b56aca327510fa1b099d30b5de6d968 /drivers/watchdog/imx7ulp_wdt.c | |
parent | 3ac4d58d5ddbd5c2ebfcced5053d10e3883c2b3b (diff) |
MLK-24824-1 watchdog: imx7ulp: Strictly follow the sequence for wdog operations
According to reference manual, the i.MX7ULP WDOG's operations except
refresh should follow below sequence:
1. disable global interrupts;
2. unlock the wdog and wait unlock bit set;
3. reconfigure the wdog and wait for reconfiguration bit set;
4. enabel global interrupts.
Strictly follow the recommended sequence can make it more robust.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Jacky Bai <ping.bai@nxp.com>
Tested-by: Peter Chen <peter.chen@nxp.com>
Tested-by: Li Jun <jun.li@nxp.com>
Diffstat (limited to 'drivers/watchdog/imx7ulp_wdt.c')
-rw-r--r-- | drivers/watchdog/imx7ulp_wdt.c | 97 |
1 files changed, 74 insertions, 23 deletions
diff --git a/drivers/watchdog/imx7ulp_wdt.c b/drivers/watchdog/imx7ulp_wdt.c index 6fecc59d7daa..922b60374295 100644 --- a/drivers/watchdog/imx7ulp_wdt.c +++ b/drivers/watchdog/imx7ulp_wdt.c @@ -4,8 +4,8 @@ */ #include <linux/clk.h> -#include <linux/init.h> #include <linux/io.h> +#include <linux/iopoll.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of.h> @@ -17,8 +17,13 @@ #define WDOG_CS_CMD32EN BIT(13) #define WDOG_CS_ULK BIT(11) #define WDOG_CS_RCS BIT(10) +#define LPO_CLK 0x1 +#define LPO_CLK_SHIFT 8 +#define WDOG_CS_CLK (LPO_CLK << LPO_CLK_SHIFT) #define WDOG_CS_EN BIT(7) #define WDOG_CS_UPDATE BIT(5) +#define WDOG_CS_WAIT BIT(1) +#define WDOG_CS_STOP BIT(0) #define WDOG_CNT 0x4 #define WDOG_TOVAL 0x8 @@ -34,6 +39,7 @@ #define DEFAULT_TIMEOUT 60 #define MAX_TIMEOUT 128 #define WDOG_CLOCK_RATE 1000 +#define WDOG_WAIT_TIMEOUT 20 static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0000); @@ -41,24 +47,48 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); struct imx7ulp_wdt_device { - struct notifier_block restart_handler; struct watchdog_device wdd; void __iomem *base; struct clk *clk; }; -static inline void imx7ulp_wdt_enable(void __iomem *base, bool enable) +static int imx7ulp_wdt_wait(void __iomem *base, u32 mask) { u32 val = readl(base + WDOG_CS); - writel(UNLOCK, base + WDOG_CNT); + if (!(val & mask) && readl_poll_timeout_atomic(base + WDOG_CS, val, + val & mask, 0, + WDOG_WAIT_TIMEOUT)) + return -ETIMEDOUT; + + return 0; +} + +static int imx7ulp_wdt_enable(struct watchdog_device *wdog, bool enable) +{ + struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); + + u32 val = readl(wdt->base + WDOG_CS); + int ret; + + local_irq_disable(); + writel(UNLOCK, wdt->base + WDOG_CNT); + ret = imx7ulp_wdt_wait(wdt->base, WDOG_CS_ULK); + if (ret) + goto enable_out; if (enable) - writel(val | WDOG_CS_EN, base + WDOG_CS); + writel(val | WDOG_CS_EN, wdt->base + WDOG_CS); else - writel(val & ~WDOG_CS_EN, base + WDOG_CS); + writel(val & ~WDOG_CS_EN, wdt->base + WDOG_CS); + imx7ulp_wdt_wait(wdt->base, WDOG_CS_RCS); + +enable_out: + local_irq_enable(); + + return ret; } -static inline bool imx7ulp_wdt_is_enabled(void __iomem *base) +static bool imx7ulp_wdt_is_enabled(void __iomem *base) { u32 val = readl(base + WDOG_CS); @@ -76,20 +106,12 @@ static int imx7ulp_wdt_ping(struct watchdog_device *wdog) static int imx7ulp_wdt_start(struct watchdog_device *wdog) { - struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); - - imx7ulp_wdt_enable(wdt->base, true); - - return 0; + return imx7ulp_wdt_enable(wdog, true); } static int imx7ulp_wdt_stop(struct watchdog_device *wdog) { - struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); - - imx7ulp_wdt_enable(wdt->base, false); - - return 0; + return imx7ulp_wdt_enable(wdog, false); } static int imx7ulp_wdt_set_timeout(struct watchdog_device *wdog, @@ -97,22 +119,37 @@ static int imx7ulp_wdt_set_timeout(struct watchdog_device *wdog, { struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); u32 val = WDOG_CLOCK_RATE * timeout; + int ret; + local_irq_disable(); writel(UNLOCK, wdt->base + WDOG_CNT); + ret = imx7ulp_wdt_wait(wdt->base, WDOG_CS_ULK); + if (ret) + goto timeout_out; writel(val, wdt->base + WDOG_TOVAL); + imx7ulp_wdt_wait(wdt->base, WDOG_CS_RCS); wdog->timeout = timeout; - return 0; +timeout_out: + local_irq_enable(); + + return ret; } static int imx7ulp_wdt_restart(struct watchdog_device *wdog, unsigned long action, void *data) { struct imx7ulp_wdt_device *wdt = watchdog_get_drvdata(wdog); + int ret; + + ret = imx7ulp_wdt_enable(wdog, true); + if (ret) + return ret; - imx7ulp_wdt_enable(wdt->base, true); - imx7ulp_wdt_set_timeout(&wdt->wdd, 1); + ret = imx7ulp_wdt_set_timeout(&wdt->wdd, 1); + if (ret) + return ret; /* wait for wdog to fire */ while (true) @@ -136,19 +173,31 @@ static const struct watchdog_info imx7ulp_wdt_info = { WDIOF_MAGICCLOSE, }; -static inline void imx7ulp_wdt_init(void __iomem *base, unsigned int timeout) +static int imx7ulp_wdt_init(void __iomem *base, unsigned int timeout) { u32 val; + int ret; + local_irq_disable(); /* unlock the wdog for reconfiguration */ writel_relaxed(UNLOCK_SEQ0, base + WDOG_CNT); writel_relaxed(UNLOCK_SEQ1, base + WDOG_CNT); + ret = imx7ulp_wdt_wait(base, WDOG_CS_ULK); + if (ret) + goto init_out; /* set an initial timeout value in TOVAL */ writel(timeout, base + WDOG_TOVAL); /* enable 32bit command sequence and reconfigure */ - val = BIT(13) | BIT(8) | BIT(5) | BIT(1) | BIT(0); + val = WDOG_CS_CMD32EN | WDOG_CS_CLK | WDOG_CS_UPDATE | + WDOG_CS_WAIT | WDOG_CS_STOP; writel(val, base + WDOG_CS); + imx7ulp_wdt_wait(base, WDOG_CS_RCS); + +init_out: + local_irq_enable(); + + return ret; } static void imx7ulp_wdt_action(void *data) @@ -199,7 +248,9 @@ static int imx7ulp_wdt_probe(struct platform_device *pdev) watchdog_stop_on_reboot(wdog); watchdog_stop_on_unregister(wdog); watchdog_set_drvdata(wdog, imx7ulp_wdt); - imx7ulp_wdt_init(imx7ulp_wdt->base, wdog->timeout * WDOG_CLOCK_RATE); + ret = imx7ulp_wdt_init(imx7ulp_wdt->base, wdog->timeout * WDOG_CLOCK_RATE); + if (ret) + return ret; return devm_watchdog_register_device(dev, wdog); } |