restart: replace reset_cpu with registered restart handlers

This replaces the reset_cpu() function which every SoC or board must
provide with registered handlers. This makes it possible to have multiple
reset functions for boards which have multiple ways to reset the machine.
Also boards which have no way at all to reset the machine no longer
have to provide a dummy reset_cpu() function.

The problem this solves is that some machines have external PMICs or
similar to reset the system which have to be preferred over the
internal SoC reset, because the PMIC can reset not only the SoC but also
the external devices.

To pick the right way to reset a machine each handler has a priority. The
default priority is 100 and all currently existing restart handlers are
registered with this priority. of_get_restart_priority() allows to retrieve
the priority from the device tree which makes it possible for boards to
give certain restart handlers a higher priority in order to use this one
instead of the default one.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 11 insertions, 10 deletions

diff --git a/arch/arm/mach-bcm2835/core.c b/arch/arm/mach-bcm2835/core.c
index 5d08012f8b..64f3781388 100644
--- a/arch/arm/mach-bcm2835/core.c
+++ b/arch/arm/mach-bcm2835/core.c
@@ -18,6 +18,7 @@
 
 #include <common.h>
 #include <init.h>
+#include <restart.h>
 
 #include <linux/clk.h>
 #include <linux/clkdev.h>
@@ -51,13 +52,6 @@ static int bcm2835_clk_init(void)
 }
 postcore_initcall(bcm2835_clk_init);
 
-static int bcm2835_dev_init(void)
-{
-	add_generic_device("bcm2835-gpio", 0, NULL, BCM2835_GPIO_BASE, 0xB0, IORESOURCE_MEM, NULL);
-	return 0;
-}
-coredevice_initcall(bcm2835_dev_init);
-
 void bcm2835_register_uart(void)
 {
 	amba_apb_device_add(NULL, "uart0-pl011", 0, BCM2835_UART0_BASE, 4096, NULL, 0);
@@ -72,7 +66,7 @@ void bcm2835_add_device_sdram(u32 size)
 }
 #define RESET_TIMEOUT 10
 
-void __noreturn reset_cpu(unsigned long addr)
+static void __noreturn bcm2835_restart_soc(struct restart_handler *rst)
 {
 	uint32_t rstc;
 
@@ -82,6 +76,13 @@ void __noreturn reset_cpu(unsigned long addr)
 	writel(PM_PASSWORD | RESET_TIMEOUT, PM_WDOG);
 	writel(PM_PASSWORD | rstc, PM_RSTC);
 
-	while (1);
+	hang();
 }
-EXPORT_SYMBOL(reset_cpu);
+
+static int bcm2835_dev_init(void)
+{
+	add_generic_device("bcm2835-gpio", 0, NULL, BCM2835_GPIO_BASE, 0xB0, IORESOURCE_MEM, NULL);
+	restart_handler_register_fn(bcm2835_restart_soc);
+	return 0;
+}
+coredevice_initcall(bcm2835_dev_init);