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authorJamie Iles <jamie@jamieiles.com>2011-12-17 13:42:37 +0000
committerJamie Iles <jamie@jamieiles.com>2011-12-18 10:48:41 +0000
commit1b46f8782c2607afa1298b0c7f7fe307fc0f7a5b (patch)
treefe154b4ed20efe29ac246418f06f24b9dd07715d /arch/arm/mach-picoxcell
parenta53bfa07369b7c3448a60d29f0fc2e81751ed0b7 (diff)
downloadlinux-linaro-stable-1b46f8782c2607afa1298b0c7f7fe307fc0f7a5b.tar.gz
ARM: picoxcell: implement watchdog restart
Allow the platform to be restarted by triggering the watchdog to expire with the shortest possible expiry. This should reset the CPU core and all on-chip peripherals. v2: - use writel_relaxed(). Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Diffstat (limited to 'arch/arm/mach-picoxcell')
-rw-r--r--arch/arm/mach-picoxcell/common.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/arch/arm/mach-picoxcell/common.c b/arch/arm/mach-picoxcell/common.c
index febee47bc116..a2e8ae8b5821 100644
--- a/arch/arm/mach-picoxcell/common.c
+++ b/arch/arm/mach-picoxcell/common.c
@@ -7,6 +7,7 @@
*
* All enquiries to support@picochip.com
*/
+#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
@@ -23,6 +24,26 @@
#include "common.h"
+#define WDT_CTRL_REG_EN_MASK (1 << 0)
+#define WDT_CTRL_REG_OFFS (0x00)
+#define WDT_TIMEOUT_REG_OFFS (0x04)
+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 picoxcell_setup_restart(void)
+{
+ struct device_node *np = of_find_compatible_node(NULL, NULL,
+ "snps,dw-apb-wdg");
+ if (WARN(!np, "unable to setup watchdog restart"))
+ return;
+
+ wdt_regs = of_iomap(np, 0);
+ WARN(!wdt_regs, "failed to remap watchdog regs");
+}
+
static struct map_desc io_map __initdata = {
.virtual = PHYS_TO_IO(PICOXCELL_PERIPH_BASE),
.pfn = __phys_to_pfn(PICOXCELL_PERIPH_BASE),
@@ -38,6 +59,7 @@ static void __init picoxcell_map_io(void)
static void __init picoxcell_init_machine(void)
{
of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
+ picoxcell_setup_restart();
}
static const char *picoxcell_dt_match[] = {
@@ -56,6 +78,20 @@ static void __init picoxcell_init_irq(void)
of_irq_init(vic_of_match);
}
+static void picoxcell_wdt_restart(char mode, const char *cmd)
+{
+ /*
+ * Configure the watchdog to reset with the shortest possible timeout
+ * and give it chance to do the reset.
+ */
+ if (wdt_regs) {
+ writel_relaxed(WDT_CTRL_REG_EN_MASK, wdt_regs + WDT_CTRL_REG_OFFS);
+ writel_relaxed(0, wdt_regs + WDT_TIMEOUT_REG_OFFS);
+ /* No sleeping, possibly atomic. */
+ mdelay(500);
+ }
+}
+
DT_MACHINE_START(PICOXCELL, "Picochip picoXcell")
.map_io = picoxcell_map_io,
.nr_irqs = NR_IRQS_LEGACY,
@@ -64,4 +100,5 @@ DT_MACHINE_START(PICOXCELL, "Picochip picoXcell")
.timer = &picoxcell_timer,
.init_machine = picoxcell_init_machine,
.dt_compat = picoxcell_dt_match,
+ .restart = picoxcell_wdt_restart,
MACHINE_END