| Message ID | 20201007223813.1638-1-sstabellini@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] xen/rpi4: implement watchdog-based reset | expand |
> On 7 Oct 2020, at 23:38, Stefano Stabellini <sstabellini@kernel.org> wrote: > > The preferred method to reboot RPi4 is PSCI. If it is not available, > touching the watchdog is required to be able to reboot the board. > > The implementation is based on > drivers/watchdog/bcm2835_wdt.c:__bcm2835_restart in Linux v5.9-rc7. > > Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> > Acked-by: Julien Grall <jgrall@amazon.com> Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> Maybe a printk if reset was not successful ? Cheers Bertrand > CC: roman@zededa.com > --- > Changes in v3: > - fix typo in commit message > - dprintk -> printk > --- > xen/arch/arm/platforms/brcm-raspberry-pi.c | 61 ++++++++++++++++++++++ > 1 file changed, 61 insertions(+) > > diff --git a/xen/arch/arm/platforms/brcm-raspberry-pi.c b/xen/arch/arm/platforms/brcm-raspberry-pi.c > index f5ae58a7d5..811b40b1a6 100644 > --- a/xen/arch/arm/platforms/brcm-raspberry-pi.c > +++ b/xen/arch/arm/platforms/brcm-raspberry-pi.c > @@ -17,6 +17,10 @@ > * GNU General Public License for more details. > */ > > +#include <xen/delay.h> > +#include <xen/mm.h> > +#include <xen/vmap.h> > +#include <asm/io.h> > #include <asm/platform.h> > > static const char *const rpi4_dt_compat[] __initconst = > @@ -37,12 +41,69 @@ static const struct dt_device_match rpi4_blacklist_dev[] __initconst = > * The aux peripheral also shares a page with the aux UART. > */ > DT_MATCH_COMPATIBLE("brcm,bcm2835-aux"), > + /* Special device used for rebooting */ > + DT_MATCH_COMPATIBLE("brcm,bcm2835-pm"), > { /* sentinel */ }, > }; > > + > +#define PM_PASSWORD 0x5a000000 > +#define PM_RSTC 0x1c > +#define PM_WDOG 0x24 > +#define PM_RSTC_WRCFG_FULL_RESET 0x00000020 > +#define PM_RSTC_WRCFG_CLR 0xffffffcf > + > +static void __iomem *rpi4_map_watchdog(void) > +{ > + void __iomem *base; > + struct dt_device_node *node; > + paddr_t start, len; > + int ret; > + > + node = dt_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm"); > + if ( !node ) > + return NULL; > + > + ret = dt_device_get_address(node, 0, &start, &len); > + if ( ret ) > + { > + printk("Cannot read watchdog register address\n"); > + return NULL; > + } > + > + base = ioremap_nocache(start & PAGE_MASK, PAGE_SIZE); > + if ( !base ) > + { > + printk("Unable to map watchdog register!\n"); > + return NULL; > + } > + > + return base; > +} > + > +static void rpi4_reset(void) > +{ > + uint32_t val; > + void __iomem *base = rpi4_map_watchdog(); > + > + if ( !base ) > + return; > + > + /* use a timeout of 10 ticks (~150us) */ > + writel(10 | PM_PASSWORD, base + PM_WDOG); > + val = readl(base + PM_RSTC); > + val &= PM_RSTC_WRCFG_CLR; > + val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET; > + writel(val, base + PM_RSTC); > + > + /* No sleeping, possibly atomic. */ > + mdelay(1); > +} > + > PLATFORM_START(rpi4, "Raspberry Pi 4") > .compatible = rpi4_dt_compat, > .blacklist_dev = rpi4_blacklist_dev, > + .reset = rpi4_reset, > .dma_bitsize = 30, > PLATFORM_END > > -- > 2.17.1 > >
On Thu, 8 Oct 2020, Bertrand Marquis wrote: > > On 7 Oct 2020, at 23:38, Stefano Stabellini <sstabellini@kernel.org> wrote: > > > > The preferred method to reboot RPi4 is PSCI. If it is not available, > > touching the watchdog is required to be able to reboot the board. > > > > The implementation is based on > > drivers/watchdog/bcm2835_wdt.c:__bcm2835_restart in Linux v5.9-rc7. > > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> > > Acked-by: Julien Grall <jgrall@amazon.com> > > Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> > > Maybe a printk if reset was not successful ? That not quite platform specific but we could add a printk to xen/arch/arm/shutdown.c:machine_restart if we are still alive after 100ms. I'll commit this patch as is and maybe send another one for machine_restart. > > CC: roman@zededa.com > > --- > > Changes in v3: > > - fix typo in commit message > > - dprintk -> printk > > --- > > xen/arch/arm/platforms/brcm-raspberry-pi.c | 61 ++++++++++++++++++++++ > > 1 file changed, 61 insertions(+) > > > > diff --git a/xen/arch/arm/platforms/brcm-raspberry-pi.c b/xen/arch/arm/platforms/brcm-raspberry-pi.c > > index f5ae58a7d5..811b40b1a6 100644 > > --- a/xen/arch/arm/platforms/brcm-raspberry-pi.c > > +++ b/xen/arch/arm/platforms/brcm-raspberry-pi.c > > @@ -17,6 +17,10 @@ > > * GNU General Public License for more details. > > */ > > > > +#include <xen/delay.h> > > +#include <xen/mm.h> > > +#include <xen/vmap.h> > > +#include <asm/io.h> > > #include <asm/platform.h> > > > > static const char *const rpi4_dt_compat[] __initconst = > > @@ -37,12 +41,69 @@ static const struct dt_device_match rpi4_blacklist_dev[] __initconst = > > * The aux peripheral also shares a page with the aux UART. > > */ > > DT_MATCH_COMPATIBLE("brcm,bcm2835-aux"), > > + /* Special device used for rebooting */ > > + DT_MATCH_COMPATIBLE("brcm,bcm2835-pm"), > > { /* sentinel */ }, > > }; > > > > + > > +#define PM_PASSWORD 0x5a000000 > > +#define PM_RSTC 0x1c > > +#define PM_WDOG 0x24 > > +#define PM_RSTC_WRCFG_FULL_RESET 0x00000020 > > +#define PM_RSTC_WRCFG_CLR 0xffffffcf > > + > > +static void __iomem *rpi4_map_watchdog(void) > > +{ > > + void __iomem *base; > > + struct dt_device_node *node; > > + paddr_t start, len; > > + int ret; > > + > > + node = dt_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm"); > > + if ( !node ) > > + return NULL; > > + > > + ret = dt_device_get_address(node, 0, &start, &len); > > + if ( ret ) > > + { > > + printk("Cannot read watchdog register address\n"); > > + return NULL; > > + } > > + > > + base = ioremap_nocache(start & PAGE_MASK, PAGE_SIZE); > > + if ( !base ) > > + { > > + printk("Unable to map watchdog register!\n"); > > + return NULL; > > + } > > + > > + return base; > > +} > > + > > +static void rpi4_reset(void) > > +{ > > + uint32_t val; > > + void __iomem *base = rpi4_map_watchdog(); > > + > > + if ( !base ) > > + return; > > + > > + /* use a timeout of 10 ticks (~150us) */ > > + writel(10 | PM_PASSWORD, base + PM_WDOG); > > + val = readl(base + PM_RSTC); > > + val &= PM_RSTC_WRCFG_CLR; > > + val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET; > > + writel(val, base + PM_RSTC); > > + > > + /* No sleeping, possibly atomic. */ > > + mdelay(1); > > +} > > + > > PLATFORM_START(rpi4, "Raspberry Pi 4") > > .compatible = rpi4_dt_compat, > > .blacklist_dev = rpi4_blacklist_dev, > > + .reset = rpi4_reset, > > .dma_bitsize = 30, > > PLATFORM_END > > > > -- > > 2.17.1 > > > > >
On Thu, Oct 8, 2020 at 12:58 AM Bertrand Marquis <Bertrand.Marquis@arm.com> wrote: > > > > > On 7 Oct 2020, at 23:38, Stefano Stabellini <sstabellini@kernel.org> wrote: > > > > The preferred method to reboot RPi4 is PSCI. If it is not available, > > touching the watchdog is required to be able to reboot the board. > > > > The implementation is based on > > drivers/watchdog/bcm2835_wdt.c:__bcm2835_restart in Linux v5.9-rc7. > > > > Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> > > Acked-by: Julien Grall <jgrall@amazon.com> > > Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> FWIW: Tested-by: Roman Shaposhnik <roman@zededa.com> Great to see it being merged -- one less custom patch for us to carry in EVE. Thanks, Roman.
> On 8 Oct 2020, at 19:27, Stefano Stabellini <sstabellini@kernel.org> wrote: > > On Thu, 8 Oct 2020, Bertrand Marquis wrote: >>> On 7 Oct 2020, at 23:38, Stefano Stabellini <sstabellini@kernel.org> wrote: >>> >>> The preferred method to reboot RPi4 is PSCI. If it is not available, >>> touching the watchdog is required to be able to reboot the board. >>> >>> The implementation is based on >>> drivers/watchdog/bcm2835_wdt.c:__bcm2835_restart in Linux v5.9-rc7. >>> >>> Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> >>> Acked-by: Julien Grall <jgrall@amazon.com> >> >> Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> >> >> Maybe a printk if reset was not successful ? > > That not quite platform specific but we could add a printk to > xen/arch/arm/shutdown.c:machine_restart if we are still alive after > 100ms. Even nicer :-) Definitely usefull to see something if for one reason reset/restart did not succeed for whatever reason. > > I'll commit this patch as is and maybe send another one for > machine_restart. Please tell me if you want me to handle that one (at the end I did request that so not really fare to ask you to do it:-) ). Cheers Bertrand
On Fri, 9 Oct 2020, Bertrand Marquis wrote: > > On 8 Oct 2020, at 19:27, Stefano Stabellini <sstabellini@kernel.org> wrote: > > > > On Thu, 8 Oct 2020, Bertrand Marquis wrote: > >>> On 7 Oct 2020, at 23:38, Stefano Stabellini <sstabellini@kernel.org> wrote: > >>> > >>> The preferred method to reboot RPi4 is PSCI. If it is not available, > >>> touching the watchdog is required to be able to reboot the board. > >>> > >>> The implementation is based on > >>> drivers/watchdog/bcm2835_wdt.c:__bcm2835_restart in Linux v5.9-rc7. > >>> > >>> Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> > >>> Acked-by: Julien Grall <jgrall@amazon.com> > >> > >> Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> > >> > >> Maybe a printk if reset was not successful ? > > > > That not quite platform specific but we could add a printk to > > xen/arch/arm/shutdown.c:machine_restart if we are still alive after > > 100ms. > > Even nicer :-) > Definitely usefull to see something if for one reason reset/restart did > not succeed for whatever reason. > > > > > I'll commit this patch as is and maybe send another one for > > machine_restart. > > Please tell me if you want me to handle that one (at the end I did request > that so not really fare to ask you to do it:-) ). Since you are volunteering, yes please :-)
Hi Stefano, > On 9 Oct 2020, at 17:33, Stefano Stabellini <sstabellini@kernel.org> wrote: > > On Fri, 9 Oct 2020, Bertrand Marquis wrote: >>> On 8 Oct 2020, at 19:27, Stefano Stabellini <sstabellini@kernel.org> wrote: >>> >>> On Thu, 8 Oct 2020, Bertrand Marquis wrote: >>>>> On 7 Oct 2020, at 23:38, Stefano Stabellini <sstabellini@kernel.org> wrote: >>>>> >>>>> The preferred method to reboot RPi4 is PSCI. If it is not available, >>>>> touching the watchdog is required to be able to reboot the board. >>>>> >>>>> The implementation is based on >>>>> drivers/watchdog/bcm2835_wdt.c:__bcm2835_restart in Linux v5.9-rc7. >>>>> >>>>> Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com> >>>>> Acked-by: Julien Grall <jgrall@amazon.com> >>>> >>>> Reviewed-by: Bertrand Marquis <bertrand.marquis@arm.com> >>>> >>>> Maybe a printk if reset was not successful ? >>> >>> That not quite platform specific but we could add a printk to >>> xen/arch/arm/shutdown.c:machine_restart if we are still alive after >>> 100ms. >> >> Even nicer :-) >> Definitely usefull to see something if for one reason reset/restart did >> not succeed for whatever reason. >> >>> >>> I'll commit this patch as is and maybe send another one for >>> machine_restart. >> >> Please tell me if you want me to handle that one (at the end I did request >> that so not really fare to ask you to do it:-) ). > > Since you are volunteering, yes please :-) Fare enough I will add this to my small fixes list :-) Cheers Bertrand
diff --git a/xen/arch/arm/platforms/brcm-raspberry-pi.c b/xen/arch/arm/platforms/brcm-raspberry-pi.c index f5ae58a7d5..811b40b1a6 100644 --- a/xen/arch/arm/platforms/brcm-raspberry-pi.c +++ b/xen/arch/arm/platforms/brcm-raspberry-pi.c @@ -17,6 +17,10 @@ * GNU General Public License for more details. */ +#include <xen/delay.h> +#include <xen/mm.h> +#include <xen/vmap.h> +#include <asm/io.h> #include <asm/platform.h> static const char *const rpi4_dt_compat[] __initconst = @@ -37,12 +41,69 @@ static const struct dt_device_match rpi4_blacklist_dev[] __initconst = * The aux peripheral also shares a page with the aux UART. */ DT_MATCH_COMPATIBLE("brcm,bcm2835-aux"), + /* Special device used for rebooting */ + DT_MATCH_COMPATIBLE("brcm,bcm2835-pm"), { /* sentinel */ }, }; + +#define PM_PASSWORD 0x5a000000 +#define PM_RSTC 0x1c +#define PM_WDOG 0x24 +#define PM_RSTC_WRCFG_FULL_RESET 0x00000020 +#define PM_RSTC_WRCFG_CLR 0xffffffcf + +static void __iomem *rpi4_map_watchdog(void) +{ + void __iomem *base; + struct dt_device_node *node; + paddr_t start, len; + int ret; + + node = dt_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm"); + if ( !node ) + return NULL; + + ret = dt_device_get_address(node, 0, &start, &len); + if ( ret ) + { + printk("Cannot read watchdog register address\n"); + return NULL; + } + + base = ioremap_nocache(start & PAGE_MASK, PAGE_SIZE); + if ( !base ) + { + printk("Unable to map watchdog register!\n"); + return NULL; + } + + return base; +} + +static void rpi4_reset(void) +{ + uint32_t val; + void __iomem *base = rpi4_map_watchdog(); + + if ( !base ) + return; + + /* use a timeout of 10 ticks (~150us) */ + writel(10 | PM_PASSWORD, base + PM_WDOG); + val = readl(base + PM_RSTC); + val &= PM_RSTC_WRCFG_CLR; + val |= PM_PASSWORD | PM_RSTC_WRCFG_FULL_RESET; + writel(val, base + PM_RSTC); + + /* No sleeping, possibly atomic. */ + mdelay(1); +} + PLATFORM_START(rpi4, "Raspberry Pi 4") .compatible = rpi4_dt_compat, .blacklist_dev = rpi4_blacklist_dev, + .reset = rpi4_reset, .dma_bitsize = 30, PLATFORM_END