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watchdog: bcm2835: Support setting reboot partition

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The Raspberry Pi firmware looks at the RSTS register to know which
partition to boot from. The reboot syscall command
LINUX_REBOOT_CMD_RESTART2 supports passing in a string argument.

Add support for passing in a partition number 0..63 to boot from.
Partition 63 is a special partiton indicating halt.
If the partition doesn't exist, the firmware falls back to partition 0.

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
This commit is contained in:
Noralf Trønnes
2016-10-07 16:50:59 +02:00
committed by Dom Cobley
parent b849f4dad1
commit dba33d7a05
1 changed files with 27 additions and 22 deletions
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49
drivers/watchdog/bcm2835_wdt.c
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@@ -32,13 +32,7 @@
#define PM_RSTC_WRCFG_SET 0x00000030 #define PM_RSTC_WRCFG_SET 0x00000030
#define PM_RSTC_WRCFG_FULL_RESET 0x00000020 #define PM_RSTC_WRCFG_FULL_RESET 0x00000020
#define PM_RSTC_RESET 0x00000102 #define PM_RSTC_RESET 0x00000102
#define PM_RSTS_PARTITION_CLR 0xfffffaaa
/*
* The Raspberry Pi firmware uses the RSTS register to know which partition
* to boot from. The partition value is spread into bits 0, 2, 4, 6, 8, 10.
* Partition 63 is a special partition used by the firmware to indicate halt.
*/
#define PM_RSTS_RASPBERRYPI_HALT 0x555
#define SECS_TO_WDOG_TICKS(x) ((x) << 16) #define SECS_TO_WDOG_TICKS(x) ((x) << 16)
#define WDOG_TICKS_TO_SECS(x) ((x) >> 16) #define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
@@ -98,9 +92,24 @@ static unsigned int bcm2835_wdt_get_timeleft(struct watchdog_device *wdog)
return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET); return WDOG_TICKS_TO_SECS(ret & PM_WDOG_TIME_SET);
} }
static void __bcm2835_restart(struct bcm2835_wdt *wdt) /*
* The Raspberry Pi firmware uses the RSTS register to know which partiton
* to boot from. The partiton value is spread into bits 0, 2, 4, 6, 8, 10.
* Partiton 63 is a special partition used by the firmware to indicate halt.
*/
static void __bcm2835_restart(struct bcm2835_wdt *wdt, u8 partition)
{ {
u32 val; u32 val, rsts;
rsts = (partition & BIT(0)) | ((partition & BIT(1)) << 1) |
((partition & BIT(2)) << 2) | ((partition & BIT(3)) << 3) |
((partition & BIT(4)) << 4) | ((partition & BIT(5)) << 5);
val = readl_relaxed(wdt->base + PM_RSTS);
val &= PM_RSTS_PARTITION_CLR;
val |= PM_PASSWORD | rsts;
writel_relaxed(val, wdt->base + PM_RSTS);
/* use a timeout of 10 ticks (~150us) */ /* use a timeout of 10 ticks (~150us) */
writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG); writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG);
@@ -118,7 +127,13 @@ static int bcm2835_restart(struct watchdog_device *wdog,
{ {
struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog); struct bcm2835_wdt *wdt = watchdog_get_drvdata(wdog);
__bcm2835_restart(wdt); unsigned long long val;
u8 partition = 0;
if (data && !kstrtoull(data, 0, &val) && val <= 63)
partition = val;
__bcm2835_restart(wdt, partition);
return 0; return 0;
} }
@@ -153,19 +168,9 @@ static struct watchdog_device bcm2835_wdt_wdd = {
static void bcm2835_power_off(void) static void bcm2835_power_off(void)
{ {
struct bcm2835_wdt *wdt = bcm2835_power_off_wdt; struct bcm2835_wdt *wdt = bcm2835_power_off_wdt;
u32 val;
/* /* Partition 63 tells the firmware that this is a halt */
* We set the watchdog hard reset bit here to distinguish this reset __bcm2835_restart(wdt, 63);
* from the normal (full) reset. bootcode.bin will not reboot after a
* hard reset.
*/
val = readl_relaxed(wdt->base + PM_RSTS);
val |= PM_PASSWORD | PM_RSTS_RASPBERRYPI_HALT;
writel_relaxed(val, wdt->base + PM_RSTS);
/* Continue with normal reset mechanism */
__bcm2835_restart(wdt);
} }
static int bcm2835_wdt_probe(struct platform_device *pdev) static int bcm2835_wdt_probe(struct platform_device *pdev)