| Message ID | 1429902534-2348-2-git-send-email-eric@anholt.net (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 04/24/2015 01:08 PM, Eric Anholt wrote: > 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. The series, Acked-by: Stephen Warren <swarren@wwwdotorg.org> Tested-by: Stephen Warren <swarren@wwwdotorg.org> > Note that power off has never worked for me, and just reboots as well. > So I can't say that I've *really* tested the power off code. The RPi can't actually power itself off, but it used to be the case that if you rebooted it after setting up a certain register configuration, the firmware would put the device into a low-power state. This did work when it was first upstreamed. However, it no longer works. I believe this was due to a change in the firmware, which is why I don't always trust the firmware. I should really check what the downstream kernel does for power off now; I assume it must have changed since the code was upstreamed.
On Friday 24 April 2015 12:08:54 Eric Anholt wrote: > +/* > + * 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; > + Instead of doing the lookup again here, I'd suggest using a static variable in the driver to store the device pointer for the device used on power_off. Make sure that the device remove callback assigns it back to NULL though and that the function checks for NULL pointer. Aside from this, the patch looks great. Arnd
On 04/25/2015 01:11 PM, Arnd Bergmann wrote: > On Friday 24 April 2015 12:08:54 Eric Anholt wrote: >> +/* >> + * 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; >> + > > Instead of doing the lookup again here, I'd suggest using a static variable > in the driver to store the device pointer for the device used on power_off. > > Make sure that the device remove callback assigns it back to NULL though > and that the function checks for NULL pointer. > Why would that be needed ? Guenter
On Sunday 26 April 2015 08:35:57 Guenter Roeck wrote: > On 04/25/2015 01:11 PM, Arnd Bergmann wrote: > > On Friday 24 April 2015 12:08:54 Eric Anholt wrote: > >> +/* > >> + * 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; > >> + > > > > Instead of doing the lookup again here, I'd suggest using a static variable > > in the driver to store the device pointer for the device used on power_off. > > > > Make sure that the device remove callback assigns it back to NULL though > > and that the function checks for NULL pointer. > > > > Why would that be needed ? devices can be unbound from drivers through sysfs, or using dynamic DT updates. If one does that, the watchdog driver will correctly destroy all information it has about the device, so if the power_off function still uses that pointer, it will crash. Arnd
On 04/27/2015 02:18 AM, Arnd Bergmann wrote: > On Sunday 26 April 2015 08:35:57 Guenter Roeck wrote: >> On 04/25/2015 01:11 PM, Arnd Bergmann wrote: >>> On Friday 24 April 2015 12:08:54 Eric Anholt wrote: >>>> +/* >>>> + * 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; >>>> + >>> >>> Instead of doing the lookup again here, I'd suggest using a static variable >>> in the driver to store the device pointer for the device used on power_off. >>> >>> Make sure that the device remove callback assigns it back to NULL though >>> and that the function checks for NULL pointer. >>> >> >> Why would that be needed ? > > devices can be unbound from drivers through sysfs, or using dynamic DT > updates. If one does that, the watchdog driver will correctly destroy > all information it has about the device, so if the power_off function > still uses that pointer, it will crash. > Without calling its remove function ? That sounds odd. Lots of drivers would break if that was really the case. Guenter
On Monday 27 April 2015 05:44:14 Guenter Roeck wrote: > On 04/27/2015 02:18 AM, Arnd Bergmann wrote: > > On Sunday 26 April 2015 08:35:57 Guenter Roeck wrote: > >> On 04/25/2015 01:11 PM, Arnd Bergmann wrote: > >>> On Friday 24 April 2015 12:08:54 Eric Anholt wrote: > >>>> +/* > >>>> + * 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; > >>>> + > >>> > >>> Instead of doing the lookup again here, I'd suggest using a static variable > >>> in the driver to store the device pointer for the device used on power_off. > >>> > >>> Make sure that the device remove callback assigns it back to NULL though > >>> and that the function checks for NULL pointer. > >>> > >> > >> Why would that be needed ? > > > > devices can be unbound from drivers through sysfs, or using dynamic DT > > updates. If one does that, the watchdog driver will correctly destroy > > all information it has about the device, so if the power_off function > > still uses that pointer, it will crash. > > > Without calling its remove function ? That sounds odd. Lots of drivers > would break if that was really the case. I'm not sure what you mean now. The remove function gets called to do the final cleanup, and afterwards the device is deleted, so the remove function should make sure that no global variables point to the device any more. This is not a concern for most other drivers, because they do not keep global pointers to device structures. Arnd
On Fri, 2015-04-24 at 12:08 -0700, Eric Anholt wrote: > 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> > Cc: linux-watchdog@vger.kernel.org Acked-by: Lubomir Rintel <lkundrak@v3.sk>
On 04/27/2015 05:48 AM, Arnd Bergmann wrote: > On Monday 27 April 2015 05:44:14 Guenter Roeck wrote: >> On 04/27/2015 02:18 AM, Arnd Bergmann wrote: >>> On Sunday 26 April 2015 08:35:57 Guenter Roeck wrote: >>>> On 04/25/2015 01:11 PM, Arnd Bergmann wrote: >>>>> On Friday 24 April 2015 12:08:54 Eric Anholt wrote: >>>>>> +/* >>>>>> + * 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; >>>>>> + >>>>> >>>>> Instead of doing the lookup again here, I'd suggest using a static variable >>>>> in the driver to store the device pointer for the device used on power_off. >>>>> >>>>> Make sure that the device remove callback assigns it back to NULL though >>>>> and that the function checks for NULL pointer. >>>>> >>>> >>>> Why would that be needed ? >>> >>> devices can be unbound from drivers through sysfs, or using dynamic DT >>> updates. If one does that, the watchdog driver will correctly destroy >>> all information it has about the device, so if the power_off function >>> still uses that pointer, it will crash. >>> >> Without calling its remove function ? That sounds odd. Lots of drivers >> would break if that was really the case. > > I'm not sure what you mean now. The remove function gets called to > do the final cleanup, and afterwards the device is deleted, so the > remove function should make sure that no global variables point to > the device any more. > > This is not a concern for most other drivers, because they do not > keep global pointers to device structures. > The pointer to the power-off handler is removed in the device remove callback, and thus won't be called after the device is unbound. Ultimately this is similar the the current code, which assumes that the call to of_find_device_by_node(np) never fails. Guenter
On Monday 27 April 2015 06:28:46 Guenter Roeck wrote: > > > > The pointer to the power-off handler is removed in the device remove callback, > and thus won't be called after the device is unbound. > > Ultimately this is similar the the current code, which assumes that the > call to of_find_device_by_node(np) never fails. > Ok, I missed that part. Yes, that works just as well. Arnd
On Fri, Apr 24, 2015 at 12:08:54PM -0700, Eric Anholt wrote: > 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> > Cc: linux-watchdog@vger.kernel.org The patch will require a rebase to v4.0-rc1. Thanks, Guenter
On Mon, Apr 27, 2015 at 09:04:32AM -0700, Guenter Roeck wrote: > On Fri, Apr 24, 2015 at 12:08:54PM -0700, Eric Anholt wrote: > > 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> > > Cc: linux-watchdog@vger.kernel.org > > The patch will require a rebase to v4.0-rc1. > s/4.0/4.1/ Guenter
On Fri, 24 Apr 2015, Eric Anholt wrote: > 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> > Cc: linux-watchdog@vger.kernel.org > --- > > Note that power off has never worked for me, and just reboots as well. > So I can't say that I've *really* tested the power off code. > > arch/arm/mach-bcm/board_bcm2835.c | 73 --------------------------------------- > drivers/watchdog/bcm2835_wdt.c | 62 +++++++++++++++++++++++++++++++++ > 2 files changed, 62 insertions(+), 73 deletions(-) Please rebase and resend, just this patch, as requested by Guenter. I'm going to take the other patch. > diff --git a/arch/arm/mach-bcm/board_bcm2835.c b/arch/arm/mach-bcm/board_bcm2835.c > index 49dd5b0..0f7b9ea 100644 > --- a/arch/arm/mach-bcm/board_bcm2835.c > +++ b/arch/arm/mach-bcm/board_bcm2835.c > @@ -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 > diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c > index 2b5a9bb..7116968 100644 > --- a/drivers/watchdog/bcm2835_wdt.c > +++ b/drivers/watchdog/bcm2835_wdt.c > @@ -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); >
Guenter Roeck <linux@roeck-us.net> writes: > On Mon, Apr 27, 2015 at 09:04:32AM -0700, Guenter Roeck wrote: >> On Fri, Apr 24, 2015 at 12:08:54PM -0700, Eric Anholt wrote: >> > 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> >> > Cc: linux-watchdog@vger.kernel.org >> >> The patch will require a rebase to v4.0-rc1. >> > s/4.0/4.1/ It will? It seems to work fine, and the diff's the same. Is there some new thing you were expecting in a rebase?
On 04/27/2015 04:12 PM, Eric Anholt wrote: > Guenter Roeck <linux@roeck-us.net> writes: > >> On Mon, Apr 27, 2015 at 09:04:32AM -0700, Guenter Roeck wrote: >>> On Fri, Apr 24, 2015 at 12:08:54PM -0700, Eric Anholt wrote: >>>> 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> >>>> Cc: linux-watchdog@vger.kernel.org >>> >>> The patch will require a rebase to v4.0-rc1. >>> >> s/4.0/4.1/ > > It will? It seems to work fine, and the diff's the same. Is there some > new thing you were expecting in a rebase? > All I can say is that it didn't apply for me. Maybe someone else has more luck. Guenter
On Mon, 27 Apr 2015, Guenter Roeck wrote: > On 04/27/2015 04:12 PM, Eric Anholt wrote: > >Guenter Roeck <linux@roeck-us.net> writes: > > > >>On Mon, Apr 27, 2015 at 09:04:32AM -0700, Guenter Roeck wrote: > >>>On Fri, Apr 24, 2015 at 12:08:54PM -0700, Eric Anholt wrote: > >>>>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> > >>>>Cc: linux-watchdog@vger.kernel.org > >>> > >>>The patch will require a rebase to v4.0-rc1. > >>> > >>s/4.0/4.1/ > > > >It will? It seems to work fine, and the diff's the same. Is there some > >new thing you were expecting in a rebase? > > > All I can say is that it didn't apply for me. Maybe someone else has more luck. I won't even try without a WDT Ack. ;)
Guenter Roeck <linux@roeck-us.net> writes: > On 04/27/2015 04:12 PM, Eric Anholt wrote: >> Guenter Roeck <linux@roeck-us.net> writes: >> >>> On Mon, Apr 27, 2015 at 09:04:32AM -0700, Guenter Roeck wrote: >>>> On Fri, Apr 24, 2015 at 12:08:54PM -0700, Eric Anholt wrote: >>>>> 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> >>>>> Cc: linux-watchdog@vger.kernel.org >>>> >>>> The patch will require a rebase to v4.0-rc1. >>>> >>> s/4.0/4.1/ >> >> It will? It seems to work fine, and the diff's the same. Is there some >> new thing you were expecting in a rebase? >> > All I can say is that it didn't apply for me. Maybe someone else has more luck. If you were trying to apply it to stock 4.1-rc1, it would fail. It was based on the for-rpi-next tree, since that's where I assume it would go in through. If you'd like to take it through your tree I could send you that one, but it'll mean conflicts for someone to resolve later.
On Fri, Apr 24, 2015 at 12:08:54PM -0700, Eric Anholt wrote: > 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> > Cc: linux-watchdog@vger.kernel.org > Acked-by: Stephen Warren <swarren@wwwdotorg.org> > Tested-by: Stephen Warren <swarren@wwwdotorg.org> > Acked-by: Lubomir Rintel <lkundrak@v3.sk> Acked-by: Guenter Roeck <linux@roeck-us.net>
On Fri, 24 Apr 2015, Eric Anholt wrote: > 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> > Cc: linux-watchdog@vger.kernel.org > --- > > Note that power off has never worked for me, and just reboots as well. > So I can't say that I've *really* tested the power off code. > > arch/arm/mach-bcm/board_bcm2835.c | 73 --------------------------------------- > drivers/watchdog/bcm2835_wdt.c | 62 +++++++++++++++++++++++++++++++++ > 2 files changed, 62 insertions(+), 73 deletions(-) Applied with Guenter's Ack. > diff --git a/arch/arm/mach-bcm/board_bcm2835.c b/arch/arm/mach-bcm/board_bcm2835.c > index 49dd5b0..0f7b9ea 100644 > --- a/arch/arm/mach-bcm/board_bcm2835.c > +++ b/arch/arm/mach-bcm/board_bcm2835.c > @@ -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 > diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c > index 2b5a9bb..7116968 100644 > --- a/drivers/watchdog/bcm2835_wdt.c > +++ b/drivers/watchdog/bcm2835_wdt.c > @@ -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); >
diff --git a/arch/arm/mach-bcm/board_bcm2835.c b/arch/arm/mach-bcm/board_bcm2835.c index 49dd5b0..0f7b9ea 100644 --- a/arch/arm/mach-bcm/board_bcm2835.c +++ b/arch/arm/mach-bcm/board_bcm2835.c @@ -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 diff --git a/drivers/watchdog/bcm2835_wdt.c b/drivers/watchdog/bcm2835_wdt.c index 2b5a9bb..7116968 100644 --- a/drivers/watchdog/bcm2835_wdt.c +++ b/drivers/watchdog/bcm2835_wdt.c @@ -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);
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> Cc: linux-watchdog@vger.kernel.org --- Note that power off has never worked for me, and just reboots as well. So I can't say that I've *really* tested the power off code. arch/arm/mach-bcm/board_bcm2835.c | 73 --------------------------------------- drivers/watchdog/bcm2835_wdt.c | 62 +++++++++++++++++++++++++++++++++ 2 files changed, 62 insertions(+), 73 deletions(-)