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

[David Lechner]

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 <da...@lechnology.com>
---
 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