[PATCH] ppc32: Add soft reset to MPC834x

This change allows mpc83xx_restart to issue a software reset.

Signed-off-by: Randy Vinson <rvinson@mvista.com>
Signed-off-by: Kumar Gala <kumar.gala@freescale.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 34 insertions, 0 deletions

diff --git a/arch/ppc/platforms/83xx/mpc834x_sys.h b/arch/ppc/platforms/83xx/mpc834x_sys.h
index 49db0f4c847e..a2f6e49d7151 100644
--- a/arch/ppc/platforms/83xx/mpc834x_sys.h
+++ b/arch/ppc/platforms/83xx/mpc834x_sys.h
@@ -28,6 +28,12 @@
 #define BCSR_PHYS_ADDR          ((uint)0xf8000000)
 #define BCSR_SIZE               ((uint)(32 * 1024))
 
+#define BCSR_MISC_REG2_OFF      0x07
+#define BCSR_MISC_REG2_PORESET  0x01
+
+#define BCSR_MISC_REG3_OFF      0x08
+#define BCSR_MISC_REG3_CNFLOCK  0x80
+
 #ifdef CONFIG_PCI
 /* PCI interrupt controller */
 #define PIRQA        MPC83xx_IRQ_IRQ4
diff --git a/arch/ppc/syslib/ppc83xx_setup.c b/arch/ppc/syslib/ppc83xx_setup.c
index c28f9d679484..843cf8873e60 100644
--- a/arch/ppc/syslib/ppc83xx_setup.c
+++ b/arch/ppc/syslib/ppc83xx_setup.c
@@ -29,6 +29,7 @@
 #include <asm/mmu.h>
 #include <asm/ppc_sys.h>
 #include <asm/kgdb.h>
+#include <asm/delay.h>
 
 #include <syslib/ppc83xx_setup.h>
 
@@ -117,7 +118,34 @@ mpc83xx_early_serial_map(void)
 void
 mpc83xx_restart(char *cmd)
 {
+        volatile unsigned char __iomem *reg;
+        unsigned char tmp;
+
+        reg = ioremap(BCSR_PHYS_ADDR, BCSR_SIZE);
+
         local_irq_disable();
+
+        /*
+         * Unlock the BCSR bits so a PRST will update the contents.
+         * Otherwise the reset asserts but doesn't clear.
+         */
+        tmp = in_8(reg + BCSR_MISC_REG3_OFF);
+        tmp |= BCSR_MISC_REG3_CNFLOCK; /* low true, high false */
+        out_8(reg + BCSR_MISC_REG3_OFF, tmp);
+
+        /*
+         * Trigger a reset via a low->high transition of the
+         * PORESET bit.
+         */
+        tmp = in_8(reg + BCSR_MISC_REG2_OFF);
+        tmp &= ~BCSR_MISC_REG2_PORESET;
+        out_8(reg + BCSR_MISC_REG2_OFF, tmp);
+
+        udelay(1);
+
+        tmp |= BCSR_MISC_REG2_PORESET;
+        out_8(reg + BCSR_MISC_REG2_OFF, tmp);
+
         for(;;);
 }