[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>

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

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(;;);
 }