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Commit 1b46f878 authored by Jamie Iles's avatar Jamie Iles
Browse files

ARM: picoxcell: implement watchdog restart 



Allow the platform to be restarted by triggering the watchdog to expire
with the shortest possible expiry.  This should reset the CPU core and
all on-chip peripherals.

v2:	- use writel_relaxed().

Signed-off-by: default avatarJamie Iles <jamie@jamieiles.com>
parent a53bfa07

arch/arm/mach-picoxcell/common.c

+37 −0
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
 *

 * All enquiries to support@picochip.com

 */

#include <linux/delay.h>

#include <linux/irq.h>

#include <linux/irqdomain.h>

#include <linux/of.h>
@@ -23,6 +24,26 @@ 


#include "common.h"



#define WDT_CTRL_REG_EN_MASK	(1 << 0)

#define WDT_CTRL_REG_OFFS	(0x00)

#define WDT_TIMEOUT_REG_OFFS	(0x04)

static void __iomem *wdt_regs;



/*

 * The machine restart method can be called from an atomic context so we won't

 * be able to ioremap the regs then.

 */

static void picoxcell_setup_restart(void)

{

	struct device_node *np = of_find_compatible_node(NULL, NULL,

							 "snps,dw-apb-wdg");

	if (WARN(!np, "unable to setup watchdog restart"))

		return;



	wdt_regs = of_iomap(np, 0);

	WARN(!wdt_regs, "failed to remap watchdog regs");

}



static struct map_desc io_map __initdata = {

	.virtual	= PHYS_TO_IO(PICOXCELL_PERIPH_BASE),

	.pfn		= __phys_to_pfn(PICOXCELL_PERIPH_BASE),
@@ -38,6 +59,7 @@ static void __init picoxcell_map_io(void) 
static void __init picoxcell_init_machine(void)

{

	of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);

	picoxcell_setup_restart();

}



static const char *picoxcell_dt_match[] = {
@@ -56,6 +78,20 @@ static void __init picoxcell_init_irq(void) 
	of_irq_init(vic_of_match);

}



static void picoxcell_wdt_restart(char mode, const char *cmd)

{

	/*

	 * Configure the watchdog to reset with the shortest possible timeout

	 * and give it chance to do the reset.

	 */

	if (wdt_regs) {

		writel_relaxed(WDT_CTRL_REG_EN_MASK, wdt_regs + WDT_CTRL_REG_OFFS);

		writel_relaxed(0, wdt_regs + WDT_TIMEOUT_REG_OFFS);

		/* No sleeping, possibly atomic. */

		mdelay(500);

	}

}



DT_MACHINE_START(PICOXCELL, "Picochip picoXcell")

	.map_io		= picoxcell_map_io,

	.nr_irqs	= NR_IRQS_LEGACY,
@@ -64,4 +100,5 @@ DT_MACHINE_START(PICOXCELL, "Picochip picoXcell") 
	.timer		= &picoxcell_timer,

	.init_machine	= picoxcell_init_machine,

	.dt_compat	= picoxcell_dt_match,

	.restart	= picoxcell_wdt_restart,

MACHINE_END