On 03/09/2018 04:06 PM, Guenter Roeck wrote:
On Fri, Mar 09, 2018 at 03:58:20PM -0600, Eddie James wrote:
From: Milton Miller <miltonm@xxxxxxxxxx>
Allow the device tree to specify a watchdog to fallover to
the alternate boot source.
The aspeeed watchdog can set a latch directing flash chip select 0 to
chip select 1, allowing boot from an alternate media if the watchdog
is not reset in time. On the ast2400 bank 1 also goes to flash bank 1,
while on the ast2500 the chip selects are swapped.
Signed-off-by: Milton Miller <miltonm@xxxxxxxxxx>
Signed-off-by: Eddie James <eajames@xxxxxxxxxxxxxxxxxx>
This is already documented in the bindings document, so the property
should be ok.
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Thanks. On a related note, our system has need of a way to determine if
it's currently booted from the alternate chip or not. It seems the only
way to tell is to look at the ast2400/2500 watchdog timeout status
register. We can add some debugfs to the aspeed driver I guess, but I
wonder if this is a common enough situation that the watchdog core could
use some debugfs or sysfs for providing that info?
Thanks,
Eddie
---
drivers/watchdog/aspeed_wdt.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index d1987d6..f41d246 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -46,6 +46,7 @@ struct aspeed_wdt_config {
#define WDT_RELOAD_VALUE 0x04
#define WDT_RESTART 0x08
#define WDT_CTRL 0x0C
+#define WDT_CTRL_BOOT_SECONDARY BIT(7)
#define WDT_CTRL_RESET_MODE_SOC (0x00 << 5)
#define WDT_CTRL_RESET_MODE_FULL_CHIP (0x01 << 5)
#define WDT_CTRL_RESET_MODE_ARM_CPU (0x10 << 5)
@@ -245,6 +246,8 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
}
if (of_property_read_bool(np, "aspeed,external-signal"))
wdt->ctrl |= WDT_CTRL_WDT_EXT;
+ if (of_property_read_bool(np, "aspeed,alt-boot"))
+ wdt->ctrl |= WDT_CTRL_BOOT_SECONDARY;
if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE) {
/*
--
1.8.3.1
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