[PATCH v2 1/2] watchdog: davinci_wdt: add restart function

From: David Lechner
Date: Sat Jan 06 2018 - 22:10:36 EST


This adds a restart function to the davinci watchdog timer driver.

This is copied from arch/arm/mach-davinci/time.c and will allow us to
remove the code from there.

Signed-off-by: David Lechner <david@xxxxxxxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
drivers/watchdog/davinci_wdt.c | 38 ++++++++++++++++++++++++++++++++++++++
1 file changed, 38 insertions(+)

diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c
index 2f46487..3e4c592 100644
--- a/drivers/watchdog/davinci_wdt.c
+++ b/drivers/watchdog/davinci_wdt.c
@@ -140,6 +140,42 @@ static unsigned int davinci_wdt_get_timeleft(struct watchdog_device *wdd)
return wdd->timeout - timer_counter;
}

+static int davinci_wdt_restart(struct watchdog_device *wdd,
+ unsigned long action, void *data)
+{
+ struct davinci_wdt_device *davinci_wdt = watchdog_get_drvdata(wdd);
+ u32 tgcr, wdtcr;
+
+ /* disable, internal clock source */
+ iowrite32(0, davinci_wdt->base + TCR);
+
+ /* reset timer, set mode to 64-bit watchdog, and unreset */
+ tgcr = 0;
+ iowrite32(tgcr, davinci_wdt->base + TGCR);
+ tgcr = TIMMODE_64BIT_WDOG | TIM12RS_UNRESET | TIM34RS_UNRESET;
+ iowrite32(tgcr, davinci_wdt->base + TGCR);
+
+ /* clear counter and period regs */
+ iowrite32(0, davinci_wdt->base + TIM12);
+ iowrite32(0, davinci_wdt->base + TIM34);
+ iowrite32(0, davinci_wdt->base + PRD12);
+ iowrite32(0, davinci_wdt->base + PRD34);
+
+ /* put watchdog in pre-active state */
+ wdtcr = WDKEY_SEQ0 | WDEN;
+ iowrite32(wdtcr, davinci_wdt->base + WDTCR);
+
+ /* put watchdog in active state */
+ wdtcr = WDKEY_SEQ1 | WDEN;
+ iowrite32(wdtcr, davinci_wdt->base + WDTCR);
+
+ /* write an invalid value to the WDKEY field to trigger a restart */
+ wdtcr = 0x00004000;
+ iowrite32(wdtcr, davinci_wdt->base + WDTCR);
+
+ return 0;
+}
+
static const struct watchdog_info davinci_wdt_info = {
.options = WDIOF_KEEPALIVEPING,
.identity = "DaVinci/Keystone Watchdog",
@@ -151,6 +187,7 @@ static const struct watchdog_ops davinci_wdt_ops = {
.stop = davinci_wdt_ping,
.ping = davinci_wdt_ping,
.get_timeleft = davinci_wdt_get_timeleft,
+ .restart = davinci_wdt_restart,
};

static int davinci_wdt_probe(struct platform_device *pdev)
@@ -195,6 +232,7 @@ static int davinci_wdt_probe(struct platform_device *pdev)

watchdog_set_drvdata(wdd, davinci_wdt);
watchdog_set_nowayout(wdd, 1);
+ watchdog_set_restart_priority(wdd, 128);

wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
davinci_wdt->base = devm_ioremap_resource(dev, wdt_mem);
--
2.7.4