powerpc/4xx: Add optional "reset_type" property to control reboot via dts

By setting "reset_type" to one of the following values, the default
software reset mechanism may be overidden. Here the possible values of
"reset_type":

  1 - PPC4xx core reset
  2 - PPC4xx chip reset
  3 - PPC4xx system reset (default)

This will be used by a new PPC440SPe board port, which needs a "chip
reset" instead of the default "system reset" to be asserted.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

1 files changed, 22 insertions, 2 deletions

diff --git a/arch/powerpc/sysdev/ppc4xx_soc.c b/arch/powerpc/sysdev/ppc4xx_soc.c
index 5c014350bf16..d3d6ce3c33b4 100644
--- a/arch/powerpc/sysdev/ppc4xx_soc.c
+++ b/arch/powerpc/sysdev/ppc4xx_soc.c
@@ -191,11 +191,31 @@ static int __init ppc4xx_l2c_probe(void)
 arch_initcall(ppc4xx_l2c_probe);
 
 /*
- * At present, this routine just applies a system reset.
+ * Apply a system reset. Alternatively a board specific value may be
+ * provided via the "reset-type" property in the cpu node.
  */
 void ppc4xx_reset_system(char *cmd)
 {
-        mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | DBCR0_RST_SYSTEM);
+        struct device_node *np;
+        u32 reset_type = DBCR0_RST_SYSTEM;
+        const u32 *prop;
+
+        np = of_find_node_by_type(NULL, "cpu");
+        if (np) {
+                prop = of_get_property(np, "reset-type", NULL);
+
+                /*
+                 * Check if property exists and if it is in range:
+                 * 1 - PPC4xx core reset
+                 * 2 - PPC4xx chip reset
+                 * 3 - PPC4xx system reset (default)
+                 */
+                if ((prop) && ((prop[0] >= 1) && (prop[0] <= 3)))
+                        reset_type = prop[0] << 28;
+        }
+
+        mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | reset_type);
+
         while (1)
                 ;       /* Just in case the reset doesn't work */
 }