Re: [PATCH v2] powerpc/4xx: Add optional "reset_type" property to control reboot via dts

[Josh Boyer <jwboyer@linux.vnet.ibm.com>]

On Wed, Apr 28, 2010 at 10:13:34AM +0200, Stefan Roese wrote:
>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>
>---
>v2:
>- Add small property description to Documentation
>- Add sanity check for property value

Thanks for the quick respin.

Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

Ben, I don't have anything else pending for -next at the moment.  Can you pick
this up yourself, or do you want me to create a pull request for just this
patch?

josh

>
> Documentation/powerpc/dts-bindings/4xx/reboot.txt |   18 +++++++++++++++
> arch/powerpc/sysdev/ppc4xx_soc.c                  |   24 +++++++++++++++++++-
> 2 files changed, 40 insertions(+), 2 deletions(-)
> create mode 100644 Documentation/powerpc/dts-bindings/4xx/reboot.txt
>
>diff --git a/Documentation/powerpc/dts-bindings/4xx/reboot.txt b/Documentation/powerpc/dts-bindings/4xx/reboot.txt
>new file mode 100644
>index 0000000..d721726
>--- /dev/null
>+++ b/Documentation/powerpc/dts-bindings/4xx/reboot.txt
>@@ -0,0 +1,18 @@
>+Reboot property to control system reboot on PPC4xx systems:
>+
>+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)
>+
>+Example:
>+
>+		cpu@0 {
>+			device_type = "cpu";
>+			model = "PowerPC,440SPe";
>+			...
>+			reset-type = <2>;	/* Use chip-reset */
>+		};
>diff --git a/arch/powerpc/sysdev/ppc4xx_soc.c b/arch/powerpc/sysdev/ppc4xx_soc.c
>index 5c01435..d3d6ce3 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 */
> }
>-- 
>1.7.1
>