diff options
| -rw-r--r-- | Documentation/devicetree/bindings/watchdog/brcm,bcm2835-pm-wdog.txt | 13 | ||||
| -rw-r--r-- | arch/arm/boot/dts/bcm2835.dtsi | 5 | ||||
| -rw-r--r-- | arch/arm/mach-bcm2835/bcm2835.c | 46 |
3 files changed, 64 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/watchdog/brcm,bcm2835-pm-wdog.txt b/Documentation/devicetree/bindings/watchdog/brcm,bcm2835-pm-wdog.txt new file mode 100644 index 000000000000..d209366b4a69 --- /dev/null +++ b/Documentation/devicetree/bindings/watchdog/brcm,bcm2835-pm-wdog.txt @@ -0,0 +1,13 @@ +BCM2835 Watchdog timer + +Required properties: + +- compatible : should be "brcm,bcm2835-pm-wdt" +- reg : Specifies base physical address and size of the registers. + +Example: + +watchdog { + compatible = "brcm,bcm2835-pm-wdt"; + reg = <0x7e100000 0x28>; +}; diff --git a/arch/arm/boot/dts/bcm2835.dtsi b/arch/arm/boot/dts/bcm2835.dtsi index 0b619398532c..5c5cbafed191 100644 --- a/arch/arm/boot/dts/bcm2835.dtsi +++ b/arch/arm/boot/dts/bcm2835.dtsi @@ -29,6 +29,11 @@ #interrupt-cells = <2>; }; + watchdog { + compatible = "brcm,bcm2835-pm-wdt"; + reg = <0x7e100000 0x28>; + }; + uart@20201000 { compatible = "brcm,bcm2835-pl011", "arm,pl011", "arm,primecell"; reg = <0x7e201000 0x1000>; diff --git a/arch/arm/mach-bcm2835/bcm2835.c b/arch/arm/mach-bcm2835/bcm2835.c index f6fea4933571..c4dd210f4db1 100644 --- a/arch/arm/mach-bcm2835/bcm2835.c +++ b/arch/arm/mach-bcm2835/bcm2835.c @@ -12,8 +12,10 @@ * GNU General Public License for more details. */ +#include <linux/delay.h> #include <linux/init.h> #include <linux/irqchip/bcm2835.h> +#include <linux/of_address.h> #include <linux/of_platform.h> #include <linux/bcm2835_timer.h> #include <linux/clk/bcm2835.h> @@ -23,6 +25,48 @@ #include <mach/bcm2835_soc.h> +#define PM_RSTC 0x1c +#define PM_WDOG 0x24 + +#define PM_PASSWORD 0x5a000000 +#define PM_RSTC_WRCFG_MASK 0x00000030 +#define PM_RSTC_WRCFG_FULL_RESET 0x00000020 + +static void __iomem *wdt_regs; + +/* + * The machine restart method can be called from an atomic context so we won't + * be able to ioremap the regs then. + */ +static void bcm2835_setup_restart(void) +{ + struct device_node *np = of_find_compatible_node(NULL, NULL, + "brcm,bcm2835-pm-wdt"); + if (WARN(!np, "unable to setup watchdog restart")) + return; + + wdt_regs = of_iomap(np, 0); + WARN(!wdt_regs, "failed to remap watchdog regs"); +} + +static void bcm2835_restart(char mode, const char *cmd) +{ + u32 val; + + if (!wdt_regs) + return; + + /* use a timeout of 10 ticks (~150us) */ + writel_relaxed(10 | PM_PASSWORD, wdt_regs + PM_WDOG); + val = readl_relaxed(wdt_regs + PM_RSTC); + val &= ~PM_RSTC_WRCFG_MASK; + val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET; + writel_relaxed(val, wdt_regs + PM_RSTC); + + /* No sleeping, possibly atomic. */ + mdelay(1); +} + static struct map_desc io_map __initdata = { .virtual = BCM2835_PERIPH_VIRT, .pfn = __phys_to_pfn(BCM2835_PERIPH_PHYS), @@ -39,6 +83,7 @@ void __init bcm2835_init(void) { int ret; + bcm2835_setup_restart(); bcm2835_init_clocks(); ret = of_platform_populate(NULL, of_default_bus_match_table, NULL, @@ -60,5 +105,6 @@ DT_MACHINE_START(BCM2835, "BCM2835") .handle_irq = bcm2835_handle_irq, .init_machine = bcm2835_init, .timer = &bcm2835_timer, + .restart = bcm2835_restart, .dt_compat = bcm2835_compat MACHINE_END |