Re: [PATCH v1 1/1] driver: watchdog: Add mtk_wdt_init for mediatek watchdog hw init
From: Guenter Roeck <linux@roeck-us.net>
Date: 2020-08-28 14:27:01
Also in:
linux-mediatek, linux-watchdog, lkml
On 8/28/20 12:49 AM, Freddy Hsin wrote:
1. add a hw initialization function 2. enable/disable the watchdog depends on the original hw setting 3. set WDOD_HW_RUNNING in start function in order to start kicker after driver probe and clear the bit in stop function Change-Id: I25aa797f3b88288f26984455e499e599e27f09fa Signed-off-by: Freddy Hsin <redacted>
The subject is misleading - what this really does it to honor that/if a watchdog is already running. However, WDOG_HW_RUNNING should not generally be set/cleared in the start/stop function. Also, calling mtk_wdt_stop is pointless if WDT_MODE_EN is not set, since clearing WDT_MODE_EN is all it does. On top of that, setting WDOG_HW_RUNNING in the probe function requires that max_hw_heartbeat_ms is set (instead of max_timeout). So if you really want to honor that the watchdog is already running at boot, you would have to initialize max_hw_heartbeat_ms, set WDOG_HW_RUNNING explicitly, and possibly call the ping function before changing the timeout. Thanks, Guenter
quoted hunk ↗ jump to hunk
--- drivers/watchdog/mtk_wdt.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-)diff --git a/drivers/watchdog/mtk_wdt.c b/drivers/watchdog/mtk_wdt.c index d6a6393..59b5061 100644 --- a/drivers/watchdog/mtk_wdt.c +++ b/drivers/watchdog/mtk_wdt.c@@ -57,6 +57,9 @@ static bool nowayout = WATCHDOG_NOWAYOUT; static unsigned int timeout; +static int mtk_wdt_start(struct watchdog_device *wdt_dev); +static int mtk_wdt_stop(struct watchdog_device *wdt_dev); + struct mtk_wdt_dev { struct watchdog_device wdt_dev; void __iomem *wdt_base;@@ -148,6 +151,19 @@ static int toprgu_register_reset_controller(struct platform_device *pdev, return ret; } +static int mtk_wdt_init(struct watchdog_device *wdt_dev) +{ + struct mtk_wdt_dev *mtk_wdt = watchdog_get_drvdata(wdt_dev); + void __iomem *wdt_base; + + wdt_base = mtk_wdt->wdt_base; + + if (readl(wdt_base + WDT_MODE) & WDT_MODE_EN) + mtk_wdt_start(wdt_dev); + else + mtk_wdt_stop(wdt_dev); +} + static int mtk_wdt_restart(struct watchdog_device *wdt_dev, unsigned long action, void *data) {@@ -206,6 +222,8 @@ static int mtk_wdt_stop(struct watchdog_device *wdt_dev) reg |= WDT_MODE_KEY; iowrite32(reg, wdt_base + WDT_MODE); + clear_bit(WDOG_HW_RUNNING, &wdt_dev->status); + return 0; }@@ -225,6 +243,8 @@ static int mtk_wdt_start(struct watchdog_device *wdt_dev) reg |= (WDT_MODE_EN | WDT_MODE_KEY); iowrite32(reg, wdt_base + WDT_MODE); + set_bit(WDOG_HW_RUNNING, &wdt_dev->status); + return 0; }@@ -274,7 +294,7 @@ static int mtk_wdt_probe(struct platform_device *pdev) watchdog_set_drvdata(&mtk_wdt->wdt_dev, mtk_wdt); - mtk_wdt_stop(&mtk_wdt->wdt_dev); + mtk_wdt_init(&mtk_wdt->wdt_dev); watchdog_stop_on_reboot(&mtk_wdt->wdt_dev); err = devm_watchdog_register_device(dev, &mtk_wdt->wdt_dev);
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