diff options
Diffstat (limited to 'drivers/watchdog/renesas_wdt.c')
| -rw-r--r-- | drivers/watchdog/renesas_wdt.c | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c index 47fce4de0110..5791198960e6 100644 --- a/drivers/watchdog/renesas_wdt.c +++ b/drivers/watchdog/renesas_wdt.c @@ -9,6 +9,7 @@ #include <linux/clk.h> #include <linux/delay.h> #include <linux/io.h> +#include <linux/iopoll.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of.h> @@ -50,6 +51,7 @@ struct rwdt_priv { struct watchdog_device wdev; unsigned long clk_rate; u8 cks; + struct clk *clk; }; static void rwdt_write(struct rwdt_priv *priv, u32 val, unsigned int reg) @@ -125,13 +127,33 @@ static unsigned int rwdt_get_timeleft(struct watchdog_device *wdev) return DIV_BY_CLKS_PER_SEC(priv, 65536 - val); } +/* needs to be atomic - no RPM, no usleep_range, no scheduling! */ static int rwdt_restart(struct watchdog_device *wdev, unsigned long action, void *data) { struct rwdt_priv *priv = watchdog_get_drvdata(wdev); + u8 val; + + clk_prepare_enable(priv->clk); + + /* Stop the timer before we modify any register */ + val = readb_relaxed(priv->base + RWTCSRA) & ~RWTCSRA_TME; + rwdt_write(priv, val, RWTCSRA); + /* Delay 2 cycles before setting watchdog counter */ + udelay(DIV_ROUND_UP(2 * 1000000, priv->clk_rate)); - rwdt_start(wdev); rwdt_write(priv, 0xffff, RWTCNT); + /* smallest divider to reboot soon */ + rwdt_write(priv, 0, RWTCSRA); + + readb_poll_timeout_atomic(priv->base + RWTCSRA, val, + !(val & RWTCSRA_WRFLG), 1, 100); + + rwdt_write(priv, RWTCSRA_TME, RWTCSRA); + + /* wait 2 cycles, so watchdog will trigger */ + udelay(DIV_ROUND_UP(2 * 1000000, priv->clk_rate)); + return 0; } @@ -191,7 +213,6 @@ static int rwdt_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct rwdt_priv *priv; - struct clk *clk; unsigned long clks_per_sec; int ret, i; u8 csra; @@ -207,13 +228,13 @@ static int rwdt_probe(struct platform_device *pdev) if (IS_ERR(priv->base)) return PTR_ERR(priv->base); - clk = devm_clk_get(dev, NULL); - if (IS_ERR(clk)) - return PTR_ERR(clk); + priv->clk = devm_clk_get(dev, NULL); + if (IS_ERR(priv->clk)) + return PTR_ERR(priv->clk); pm_runtime_enable(dev); pm_runtime_get_sync(dev); - priv->clk_rate = clk_get_rate(clk); + priv->clk_rate = clk_get_rate(priv->clk); csra = readb_relaxed(priv->base + RWTCSRA); priv->wdev.bootstatus = csra & RWTCSRA_WOVF ? WDIOF_CARDRESET : 0; pm_runtime_put(dev); |