From 0e690096e05c3b4e806381ff38124dbdae3ba877 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= Date: Fri, 7 Oct 2016 16:50:59 +0200 Subject: [PATCH] watchdog: bcm2835: Support setting reboot partition MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 --- drivers/watchdog/bcm2835_wdt.c | 61 +++++++++++++++++++++++++----------------- 1 file changed, 36 insertions(+), 25 deletions(-) --- a/drivers/watchdog/bcm2835_wdt.c +++ b/drivers/watchdog/bcm2835_wdt.c @@ -35,13 +35,7 @@ #define PM_RSTC_WRCFG_SET 0x00000030 #define PM_RSTC_WRCFG_FULL_RESET 0x00000020 #define PM_RSTC_RESET 0x00000102 - -/* - * 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. - */ -#define PM_RSTS_RASPBERRYPI_HALT 0x555 +#define PM_RSTS_PARTITION_CLR 0xfffffaaa #define SECS_TO_WDOG_TICKS(x) ((x) << 16) #define WDOG_TICKS_TO_SECS(x) ((x) >> 16) @@ -111,15 +105,28 @@ static struct watchdog_device bcm2835_wd .timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET), }; -static int -bcm2835_restart(struct notifier_block *this, unsigned long mode, void *cmd) +/* + * 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) { - struct bcm2835_wdt *wdt = container_of(this, struct bcm2835_wdt, - restart_handler); - 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) */ writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG); + val = readl_relaxed(wdt->base + PM_RSTC); val &= PM_RSTC_WRCFG_CLR; val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET; @@ -127,6 +134,20 @@ bcm2835_restart(struct notifier_block *t /* No sleeping, possibly atomic. */ mdelay(1); +} + +static int bcm2835_restart_notifier_call(struct notifier_block *this, + unsigned long mode, void *cmd) +{ + struct bcm2835_wdt *wdt = container_of(this, struct bcm2835_wdt, + restart_handler); + unsigned long long val; + u8 partition = 0; + + if (cmd && !kstrtoull(cmd, 0, &val) && val <= 63) + partition = val; + + bcm2835_restart(wdt, partition); return 0; } @@ -142,19 +163,9 @@ static void bcm2835_power_off(void) of_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm-wdt"); struct platform_device *pdev = of_find_device_by_node(np); struct bcm2835_wdt *wdt = platform_get_drvdata(pdev); - u32 val; - - /* - * We set the watchdog hard reset bit here to distinguish this reset - * 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->restart_handler, REBOOT_HARD, NULL); + /* Partition 63 tells the firmware that this is a halt */ + bcm2835_restart(wdt, 63); } static int bcm2835_wdt_probe(struct platform_device *pdev) @@ -188,7 +199,7 @@ static int bcm2835_wdt_probe(struct plat return err; } - wdt->restart_handler.notifier_call = bcm2835_restart; + wdt->restart_handler.notifier_call = bcm2835_restart_notifier_call; wdt->restart_handler.priority = 128; register_restart_handler(&wdt->restart_handler); if (pm_power_off == NULL)