| Message ID | 1518457475-4480-13-git-send-email-fabrizio.castro@bp.renesas.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Mon, Feb 12, 2018 at 05:44:21PM +0000, Fabrizio Castro wrote: > Due to commits: > * "ARM: shmobile: Add watchdog support", > * "ARM: shmobile: rcar-gen2: Add watchdog support", and > * "soc: renesas: rcar-rst: Enable watchdog as reset trigger for Gen2", > we now have everything we needed for the watchdog to work on Gen2 and > RZ/G1. > > This commit adds "renesas,rcar-gen2-wdt" as compatible string for R-Car > Gen2 and RZ/G1, and since on those platforms the rwdt clock needs to be > always ON, when suspending to RAM we need to explicitly disable the > counting by clearing TME from RWTCSRA. > > Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com> > Signed-off-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> > --- > v4->v5: > * various improvements suggested by Wolfram > > drivers/watchdog/renesas_wdt.c | 27 ++++++++++++++++++++++----- > 1 file changed, 22 insertions(+), 5 deletions(-) > > diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c > index 831ef83..e972b7b 100644 > --- a/drivers/watchdog/renesas_wdt.c > +++ b/drivers/watchdog/renesas_wdt.c > @@ -203,13 +203,29 @@ static int rwdt_remove(struct platform_device *pdev) > return 0; > } > > -/* > - * This driver does also fit for R-Car Gen2 (r8a779[0-4]) WDT. However, for SMP > - * to work there, one also needs a RESET (RST) driver which does not exist yet > - * due to HW issues. This needs to be solved before adding compatibles here. > - */ > +static int __maybe_unused rwdt_suspend(struct device *dev) > +{ > + struct rwdt_priv *priv = dev_get_drvdata(dev); > + > + if (watchdog_active(&priv->wdev)) > + rwdt_write(priv, priv->cks, RWTCSRA); > + return 0; > +} > + > +static int __maybe_unused rwdt_resume(struct device *dev) > +{ > + struct rwdt_priv *priv = dev_get_drvdata(dev); > + > + if (watchdog_active(&priv->wdev)) > + rwdt_write(priv, priv->cks | RWTCSRA_TME, RWTCSRA); > + return 0; > +} > + > +static SIMPLE_DEV_PM_OPS(rwdt_pm_ops, rwdt_suspend, rwdt_resume); > + > static const struct of_device_id rwdt_ids[] = { > { .compatible = "renesas,rcar-gen3-wdt", }, > + { .compatible = "renesas,rcar-gen2-wdt", }, > { /* sentinel */ } > }; > MODULE_DEVICE_TABLE(of, rwdt_ids); > @@ -218,6 +234,7 @@ static struct platform_driver rwdt_driver = { > .driver = { > .name = "renesas_wdt", > .of_match_table = rwdt_ids, > + .pm = &rwdt_pm_ops, > }, > .probe = rwdt_probe, > .remove = rwdt_remove, > -- > 2.7.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-clk" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Feb 12, 2018 at 05:44:21PM +0000, Fabrizio Castro wrote: > Due to commits: > * "ARM: shmobile: Add watchdog support", > * "ARM: shmobile: rcar-gen2: Add watchdog support", and > * "soc: renesas: rcar-rst: Enable watchdog as reset trigger for Gen2", > we now have everything we needed for the watchdog to work on Gen2 and > RZ/G1. > > This commit adds "renesas,rcar-gen2-wdt" as compatible string for R-Car > Gen2 and RZ/G1, and since on those platforms the rwdt clock needs to be > always ON, when suspending to RAM we need to explicitly disable the > counting by clearing TME from RWTCSRA. > > Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com> > Signed-off-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com> > --- > v4->v5: > * various improvements suggested by Wolfram > Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Hi Fabrizio, On Mon, Feb 12, 2018 at 6:44 PM, Fabrizio Castro <fabrizio.castro@bp.renesas.com> wrote: > Due to commits: > * "ARM: shmobile: Add watchdog support", > * "ARM: shmobile: rcar-gen2: Add watchdog support", and > * "soc: renesas: rcar-rst: Enable watchdog as reset trigger for Gen2", > we now have everything we needed for the watchdog to work on Gen2 and > RZ/G1. > > This commit adds "renesas,rcar-gen2-wdt" as compatible string for R-Car > Gen2 and RZ/G1, and since on those platforms the rwdt clock needs to be > always ON, when suspending to RAM we need to explicitly disable the > counting by clearing TME from RWTCSRA. > > Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com> > Signed-off-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com> Thanks for your patch! I verified this works on R-Car Gen2, so Reviewed-and-Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Still, more comments below... > --- a/drivers/watchdog/renesas_wdt.c > +++ b/drivers/watchdog/renesas_wdt.c > @@ -203,13 +203,29 @@ static int rwdt_remove(struct platform_device *pdev) > return 0; > } > > -/* > - * This driver does also fit for R-Car Gen2 (r8a779[0-4]) WDT. However, for SMP > - * to work there, one also needs a RESET (RST) driver which does not exist yet > - * due to HW issues. This needs to be solved before adding compatibles here. > - */ > +static int __maybe_unused rwdt_suspend(struct device *dev) > +{ > + struct rwdt_priv *priv = dev_get_drvdata(dev); > + > + if (watchdog_active(&priv->wdev)) > + rwdt_write(priv, priv->cks, RWTCSRA); > + return 0; > +} > + > +static int __maybe_unused rwdt_resume(struct device *dev) > +{ > + struct rwdt_priv *priv = dev_get_drvdata(dev); > + > + if (watchdog_active(&priv->wdev)) > + rwdt_write(priv, priv->cks | RWTCSRA_TME, RWTCSRA); Writing to this register is not sufficient on R-Car Gen3, where PSCI suspend powers down the whole SoC. Hence all WDT register content is lost, causing the watchdog timeout never to trigger. Note that this issue is pre-existing, and not caused by your patch. This can be fixed by replacing the RWTCSRA register writes in the suspend/resume handlers by calls to rwdt_stop() resp. rwdt_start(), like is done in the BSP in commit e406980763f18f38 ("watchdog: renesas-wdt: Support the suspend/resume"). Note that this would cause a small change in behavior on R-Car Gen2, where the timeout would be reset on resume, instead of continuing where stopped before. I don't think that hurts, though. Since I was always a bit uncomfortable with this patch doing two things at once (1. suspend/resume, 2. "renesas,rcar-gen2-wdt" matching), I think it would be better to take the patch from the BSP first, and add support for "renesas,rcar-gen2-wdt" in a subsequent patch. Does the above make sense? Do you agree? Thanks! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-clk" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Geert, thank you for your feedback! > Subject: Re: [PATCH v5 12/26] watchdog: renesas_wdt: Add R-Car Gen2 support > > Hi Fabrizio, > > On Mon, Feb 12, 2018 at 6:44 PM, Fabrizio Castro > <fabrizio.castro@bp.renesas.com> wrote: > > Due to commits: > > * "ARM: shmobile: Add watchdog support", > > * "ARM: shmobile: rcar-gen2: Add watchdog support", and > > * "soc: renesas: rcar-rst: Enable watchdog as reset trigger for Gen2", > > we now have everything we needed for the watchdog to work on Gen2 and > > RZ/G1. > > > > This commit adds "renesas,rcar-gen2-wdt" as compatible string for R-Car > > Gen2 and RZ/G1, and since on those platforms the rwdt clock needs to be > > always ON, when suspending to RAM we need to explicitly disable the > > counting by clearing TME from RWTCSRA. > > > > Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com> > > Signed-off-by: Ramesh Shanmugasundaram <ramesh.shanmugasundaram@bp.renesas.com> > > Thanks for your patch! > > I verified this works on R-Car Gen2, so > Reviewed-and-Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> > > Still, more comments below... > > > --- a/drivers/watchdog/renesas_wdt.c > > +++ b/drivers/watchdog/renesas_wdt.c > > @@ -203,13 +203,29 @@ static int rwdt_remove(struct platform_device *pdev) > > return 0; > > } > > > > -/* > > - * This driver does also fit for R-Car Gen2 (r8a779[0-4]) WDT. However, for SMP > > - * to work there, one also needs a RESET (RST) driver which does not exist yet > > - * due to HW issues. This needs to be solved before adding compatibles here. > > - */ > > +static int __maybe_unused rwdt_suspend(struct device *dev) > > +{ > > + struct rwdt_priv *priv = dev_get_drvdata(dev); > > + > > + if (watchdog_active(&priv->wdev)) > > + rwdt_write(priv, priv->cks, RWTCSRA); > > + return 0; > > +} > > + > > +static int __maybe_unused rwdt_resume(struct device *dev) > > +{ > > + struct rwdt_priv *priv = dev_get_drvdata(dev); > > + > > + if (watchdog_active(&priv->wdev)) > > + rwdt_write(priv, priv->cks | RWTCSRA_TME, RWTCSRA); > > Writing to this register is not sufficient on R-Car Gen3, where PSCI > suspend powers down the whole SoC. Hence all WDT register content is lost, > causing the watchdog timeout never to trigger. > Note that this issue is pre-existing, and not caused by your patch. > > This can be fixed by replacing the RWTCSRA register writes in the > suspend/resume handlers by calls to rwdt_stop() resp. rwdt_start(), like is > done in the BSP in commit e406980763f18f38 ("watchdog: renesas-wdt: Support > the suspend/resume"). Note that this would cause a small change in behavior > on R-Car Gen2, where the timeout would be reset on resume, instead of > continuing where stopped before. I don't think that hurts, though. I see, well I believe we can make both of us happy by addressing Gen3 problems and preserving the original behaviour from Gen2. I am going to send a new series to address this shortly. > > Since I was always a bit uncomfortable with this patch doing two things at > once (1. suspend/resume, 2. "renesas,rcar-gen2-wdt" matching), I think it > would be better to take the patch from the BSP first, and add support for > "renesas,rcar-gen2-wdt" in a subsequent patch. I agree, I'll split the patch and submit suspend/resume first, Gen2 compatibility next. Thanks, Fab > > Does the above make sense? > Do you agree? > > Thanks! > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds Renesas Electronics Europe Ltd, Dukes Meadow, Millboard Road, Bourne End, Buckinghamshire, SL8 5FH, UK. Registered in England & Wales under Registered No. 04586709.
diff --git a/drivers/watchdog/renesas_wdt.c b/drivers/watchdog/renesas_wdt.c index 831ef83..e972b7b 100644 --- a/drivers/watchdog/renesas_wdt.c +++ b/drivers/watchdog/renesas_wdt.c @@ -203,13 +203,29 @@ static int rwdt_remove(struct platform_device *pdev) return 0; } -/* - * This driver does also fit for R-Car Gen2 (r8a779[0-4]) WDT. However, for SMP - * to work there, one also needs a RESET (RST) driver which does not exist yet - * due to HW issues. This needs to be solved before adding compatibles here. - */ +static int __maybe_unused rwdt_suspend(struct device *dev) +{ + struct rwdt_priv *priv = dev_get_drvdata(dev); + + if (watchdog_active(&priv->wdev)) + rwdt_write(priv, priv->cks, RWTCSRA); + return 0; +} + +static int __maybe_unused rwdt_resume(struct device *dev) +{ + struct rwdt_priv *priv = dev_get_drvdata(dev); + + if (watchdog_active(&priv->wdev)) + rwdt_write(priv, priv->cks | RWTCSRA_TME, RWTCSRA); + return 0; +} + +static SIMPLE_DEV_PM_OPS(rwdt_pm_ops, rwdt_suspend, rwdt_resume); + static const struct of_device_id rwdt_ids[] = { { .compatible = "renesas,rcar-gen3-wdt", }, + { .compatible = "renesas,rcar-gen2-wdt", }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, rwdt_ids); @@ -218,6 +234,7 @@ static struct platform_driver rwdt_driver = { .driver = { .name = "renesas_wdt", .of_match_table = rwdt_ids, + .pm = &rwdt_pm_ops, }, .probe = rwdt_probe, .remove = rwdt_remove,