[POWERPC] Add restart support for mpc52xx based platforms
Add common helper routines: mpc52xx_map_wdt() and mpc52xx_restart().
Signed-off-by: Marian Balakowicz <m8@semihalf.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/arch/powerpc/platforms/52xx/mpc52xx_common.c b/arch/powerpc/platforms/52xx/mpc52xx_common.c
index 74b4b41..9850685 100644
--- a/arch/powerpc/platforms/52xx/mpc52xx_common.c
+++ b/arch/powerpc/platforms/52xx/mpc52xx_common.c
@@ -18,6 +18,13 @@
#include <asm/prom.h>
#include <asm/mpc52xx.h>
+/*
+ * This variable is mapped in mpc52xx_map_wdt() and used in mpc52xx_restart().
+ * Permanent mapping is required because mpc52xx_restart() can be called
+ * from interrupt context while node mapping (which calls ioremap())
+ * cannot be used at such point.
+ */
+static volatile struct mpc52xx_gpt *mpc52xx_wdt = NULL;
static void __iomem *
mpc52xx_map_node(struct device_node *ofn)
@@ -126,3 +133,46 @@
"Error while probing of_platform bus\n");
}
+void __init
+mpc52xx_map_wdt(void)
+{
+ const void *has_wdt;
+ struct device_node *np;
+
+ /* mpc52xx_wdt is mapped here and used in mpc52xx_restart,
+ * possibly from a interrupt context. wdt is only implement
+ * on a gpt0, so check has-wdt property before mapping.
+ */
+ for_each_compatible_node(np, NULL, "fsl,mpc5200-gpt") {
+ has_wdt = of_get_property(np, "fsl,has-wdt", NULL);
+ if (has_wdt) {
+ mpc52xx_wdt = mpc52xx_map_node(np);
+ return;
+ }
+ }
+ for_each_compatible_node(np, NULL, "mpc5200-gpt") {
+ has_wdt = of_get_property(np, "has-wdt", NULL);
+ if (has_wdt) {
+ mpc52xx_wdt = mpc52xx_map_node(np);
+ return;
+ }
+ }
+}
+
+void
+mpc52xx_restart(char *cmd)
+{
+ local_irq_disable();
+
+ /* Turn on the watchdog and wait for it to expire.
+ * It effectively does a reset. */
+ if (mpc52xx_wdt) {
+ out_be32(&mpc52xx_wdt->mode, 0x00000000);
+ out_be32(&mpc52xx_wdt->count, 0x000000ff);
+ out_be32(&mpc52xx_wdt->mode, 0x00009004);
+ } else
+ printk("mpc52xx_restart: Can't access wdt. "
+ "Restart impossible, system halted.\n");
+
+ while (1);
+}
diff --git a/include/asm-powerpc/mpc52xx.h b/include/asm-powerpc/mpc52xx.h
index 8e42846..fcb2ebb 100644
--- a/include/asm-powerpc/mpc52xx.h
+++ b/include/asm-powerpc/mpc52xx.h
@@ -259,6 +259,9 @@
extern int __init mpc52xx_add_bridge(struct device_node *node);
+extern void __init mpc52xx_map_wdt(void);
+extern void mpc52xx_restart(char *cmd);
+
#endif /* __ASSEMBLY__ */
#ifdef CONFIG_PM
