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ARM: bcm2835: Move the restart/power_off handling to the WDT driver

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Since the WDT is what's used to drive restart and power off, it makes
more sense to keep it there, where the regs are already mapped and
definitions for them provided.  Note that this means you may need to
add CONFIG_BCM2835_WDT to retain functionality of your kernel.

Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Eric Anholt 2015-04-24 12:08:54 -07:00 committed by Lee Jones
parent ba9acf9c0f
commit 33a9f5bc15
2 changed files with 62 additions and 73 deletions
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73
arch/arm/mach-bcm/board_bcm2835.c
View File

@ -12,7 +12,6 @@
* GNU General Public License for more details.
*/
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/irqchip.h>
#include <linux/of_address.h>
@ -22,81 +21,10 @@
#include <asm/mach/arch.h>
#include <asm/mach/map.h>
#define PM_RSTC 0x1c
#define PM_RSTS 0x20
#define PM_WDOG 0x24
#define PM_PASSWORD 0x5a000000
#define PM_RSTC_WRCFG_MASK 0x00000030
#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
#define PM_RSTS_HADWRH_SET 0x00000040
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 bcm2835_setup_restart(void)
{
struct device_node *np = of_find_compatible_node(NULL, NULL,
"brcm,bcm2835-pm-wdt");
if (WARN(!np, "unable to setup watchdog restart"))
return;
wdt_regs = of_iomap(np, 0);
WARN(!wdt_regs, "failed to remap watchdog regs");
}
static void bcm2835_restart(enum reboot_mode mode, const char *cmd)
{
u32 val;
if (!wdt_regs)
return;
/* use a timeout of 10 ticks (~150us) */
writel_relaxed(10 | PM_PASSWORD, wdt_regs + PM_WDOG);
val = readl_relaxed(wdt_regs + PM_RSTC);
val &= ~PM_RSTC_WRCFG_MASK;
val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET;
writel_relaxed(val, wdt_regs + PM_RSTC);
/* No sleeping, possibly atomic. */
mdelay(1);
}
/*
* We can't really power off, but if we do the normal reset scheme, and
* indicate to bootcode.bin not to reboot, then most of the chip will be
* powered off.
*/
static void bcm2835_power_off(void)
{
u32 val;
/*
* We set the watchdog hard reset bit here to distinguish this reset
* from the normal (full) reset. bootcode.bin will not reboot after a
* hard reset.
*/
val = readl_relaxed(wdt_regs + PM_RSTS);
val &= ~PM_RSTC_WRCFG_MASK;
val |= PM_PASSWORD | PM_RSTS_HADWRH_SET;
writel_relaxed(val, wdt_regs + PM_RSTS);
/* Continue with normal reset mechanism */
bcm2835_restart(REBOOT_HARD, "");
}
static void __init bcm2835_init(void)
{
int ret;
bcm2835_setup_restart();
if (wdt_regs)
pm_power_off = bcm2835_power_off;
bcm2835_init_clocks();
ret = of_platform_populate(NULL, of_default_bus_match_table, NULL,
@ -114,6 +42,5 @@ static const char * const bcm2835_compat[] = {
DT_MACHINE_START(BCM2835, "BCM2835")
.init_machine = bcm2835_init,
.restart = bcm2835_restart,
.dt_compat = bcm2835_compat
MACHINE_END

62
drivers/watchdog/bcm2835_wdt.c
View File

@ -13,20 +13,25 @@
* option) any later version.
*/
#include <linux/delay.h>
#include <linux/reboot.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#define PM_RSTC 0x1c
#define PM_RSTS 0x20
#define PM_WDOG 0x24
#define PM_PASSWORD 0x5a000000
#define PM_WDOG_TIME_SET 0x000fffff
#define PM_RSTC_WRCFG_CLR 0xffffffcf
#define PM_RSTS_HADWRH_SET 0x00000040
#define PM_RSTC_WRCFG_SET 0x00000030
#define PM_RSTC_WRCFG_FULL_RESET 0x00000020
#define PM_RSTC_RESET 0x00000102
@ -37,6 +42,7 @@
struct bcm2835_wdt {
void __iomem *base;
spinlock_t lock;
struct notifier_block restart_handler;
};
static unsigned int heartbeat;
@ -106,6 +112,53 @@ static struct watchdog_device bcm2835_wdt_wdd = {
.timeout = WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
};
static int
bcm2835_restart(struct notifier_block *this, unsigned long mode, void *cmd)
{
struct bcm2835_wdt *wdt = container_of(this, struct bcm2835_wdt,
restart_handler);
u32 val;
/* use a timeout of 10 ticks (~150us) */
writel_relaxed(10 | PM_PASSWORD, wdt->base + PM_WDOG);
val = readl_relaxed(wdt->base + PM_RSTC);
val &= PM_RSTC_WRCFG_CLR;
val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET;
writel_relaxed(val, wdt->base + PM_RSTC);
/* No sleeping, possibly atomic. */
mdelay(1);
return 0;
}
/*
* We can't really power off, but if we do the normal reset scheme, and
* indicate to bootcode.bin not to reboot, then most of the chip will be
* powered off.
*/
static void bcm2835_power_off(void)
{
struct device_node *np =
of_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm-wdt");
struct platform_device *pdev = of_find_device_by_node(np);
struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
u32 val;
/*
* We set the watchdog hard reset bit here to distinguish this reset
* from the normal (full) reset. bootcode.bin will not reboot after a
* hard reset.
*/
val = readl_relaxed(wdt->base + PM_RSTS);
val &= PM_RSTC_WRCFG_CLR;
val |= PM_PASSWORD | PM_RSTS_HADWRH_SET;
writel_relaxed(val, wdt->base + PM_RSTS);
/* Continue with normal reset mechanism */
bcm2835_restart(&wdt->restart_handler, REBOOT_HARD, NULL);
}
static int bcm2835_wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@ -136,6 +189,12 @@ static int bcm2835_wdt_probe(struct platform_device *pdev)
return err;
}
wdt->restart_handler.notifier_call = bcm2835_restart;
wdt->restart_handler.priority = 128;
register_restart_handler(&wdt->restart_handler);
if (pm_power_off == NULL)
pm_power_off = bcm2835_power_off;
dev_info(dev, "Broadcom BCM2835 watchdog timer");
return 0;
}
@ -144,6 +203,9 @@ static int bcm2835_wdt_remove(struct platform_device *pdev)
{
struct bcm2835_wdt *wdt = platform_get_drvdata(pdev);
unregister_restart_handler(&wdt->restart_handler);
if (pm_power_off == bcm2835_power_off)
pm_power_off = NULL;
watchdog_unregister_device(&bcm2835_wdt_wdd);
iounmap(wdt->base);