| Message ID | 20240618222403.464872-3-prabhakar.mahadev-lad.rj@bp.renesas.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add Watchdog Timer driver for Renesas RZ/V2H(P) SoC | expand |
Hi, Prabhakar, On 19.06.2024 01:24, Prabhakar wrote: > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> > > Add Watchdog Timer driver for RZ/V2H(P) SoC. > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> > --- > drivers/watchdog/Kconfig | 8 ++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/rzv2h_wdt.c | 248 +++++++++++++++++++++++++++++++++++ > 3 files changed, 257 insertions(+) > create mode 100644 drivers/watchdog/rzv2h_wdt.c > > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index 85eea38dbdf4..3f7bcc10ccc2 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -938,6 +938,14 @@ config RENESAS_RZG2LWDT > This driver adds watchdog support for the integrated watchdogs in the > Renesas RZ/G2L SoCs. These watchdogs can be used to reset a system. > > +config RENESAS_RZV2HWDT > + tristate "Renesas RZ/V2H(P) WDT Watchdog" > + depends on ARCH_RENESAS || COMPILE_TEST > + select WATCHDOG_CORE > + help > + This driver adds watchdog support for the integrated watchdogs in the > + Renesas RZ/V2H(P) SoCs. These watchdogs can be used to reset a system. > + > config ASPEED_WATCHDOG > tristate "Aspeed BMC watchdog support" > depends on ARCH_ASPEED || COMPILE_TEST > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index 2d1117564f5b..295909a1b3b9 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -86,6 +86,7 @@ obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o > obj-$(CONFIG_RENESAS_RZAWDT) += rza_wdt.o > obj-$(CONFIG_RENESAS_RZN1WDT) += rzn1_wdt.o > obj-$(CONFIG_RENESAS_RZG2LWDT) += rzg2l_wdt.o > +obj-$(CONFIG_RENESAS_RZV2HWDT) += rzv2h_wdt.o > obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o > obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o > obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o > diff --git a/drivers/watchdog/rzv2h_wdt.c b/drivers/watchdog/rzv2h_wdt.c > new file mode 100644 > index 000000000000..08f97b4bab7f > --- /dev/null > +++ b/drivers/watchdog/rzv2h_wdt.c > @@ -0,0 +1,248 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Renesas RZ/V2H(P) WDT Watchdog Driver > + * > + * Copyright (C) 2024 Renesas Electronics Corporation. > + */ > +#include <linux/bitops.h> > +#include <linux/clk.h> > +#include <linux/delay.h> > +#include <linux/io.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/platform_device.h> > +#include <linux/pm_runtime.h> > +#include <linux/reset.h> > +#include <linux/units.h> > +#include <linux/watchdog.h> > + > +#define WDTRR 0x00 /* RW, 8 */ > +#define WDTCR 0x02 /* RW, 16 */ > +#define WDTRCR 0x06 /* RW, 8 */ > + > +#define WDTCR_TOPS_1024 0x00 > +#define WDTCR_TOPS_16384 0x03 > + > +#define WDTCR_CKS_CLK_1 0x00 > +#define WDTCR_CKS_CLK_256 0x50 > + > +#define WDTCR_RPES_0 0x300 > +#define WDTCR_RPES_75 0x000 > + > +#define WDTCR_RPSS_25 0x00 > +#define WDTCR_RPSS_100 0x3000 > + > +#define WDTRCR_RSTIRQS BIT(7) > + > +#define CLOCK_DIV_BY_256 256 > + > +#define WDT_DEFAULT_TIMEOUT 60U > + > +static bool nowayout = WATCHDOG_NOWAYOUT; > +module_param(nowayout, bool, 0); > +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" > + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); > + > +struct rzv2h_wdt_priv { > + void __iomem *base; > + struct watchdog_device wdev; > + struct reset_control *rstc; You can keep the pointers first to save some padding, if any. > + unsigned long oscclk_rate; > +}; > + > +static u32 rzv2h_wdt_get_cycle_usec(struct rzv2h_wdt_priv *priv, > + unsigned long cycle, > + u16 wdttime) > +{ > + int clock_division_ratio; > + u64 timer_cycle_us; > + > + clock_division_ratio = CLOCK_DIV_BY_256; > + > + timer_cycle_us = clock_division_ratio * (wdttime + 1) * MICRO; > + > + return div64_ul(timer_cycle_us, cycle); > +} > + > +static int rzv2h_wdt_ping(struct watchdog_device *wdev) > +{ > + struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev); > + unsigned long delay; > + > + writeb(0x0, priv->base + WDTRR); > + writeb(0xFF, priv->base + WDTRR); > + > + /* > + * Refreshing the down-counter requires up to 4 cycles > + * of the signal for counting > + */ > + delay = 4 * rzv2h_wdt_get_cycle_usec(priv, priv->oscclk_rate, 0); > + udelay(delay); > + > + return 0; > +} > + > +static void rzv2h_wdt_setup(struct watchdog_device *wdev, u16 wdtcr) > +{ > + struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev); > + > + writew(wdtcr, priv->base + WDTCR); > + > + /* LSI needs RSTIRQS to be cleared */ > + writeb(readb(priv->base + WDTRCR) & ~WDTRCR_RSTIRQS, priv->base + WDTRCR); > +} > + > +static int rzv2h_wdt_start(struct watchdog_device *wdev) > +{ > + pm_runtime_get_sync(wdev->parent); You may consider using pm_runtime_resume_and_get() which takes care of failures from __pm_runtime_resume(), if any. > + > + /* > + * WDTCR > + * - CKS[7:4] - Clock Division Ratio Select - 0101b: oscclk/256 > + * - RPSS[13:12] - Window Start Position Select - 11b: 100% > + * - RPES[9:8] - Window End Position Select - 11b: 0% > + * - TOPS[1:0] - Timeout Period Select - 11b: 16384 cycles (3FFFh) > + */ > + rzv2h_wdt_setup(wdev, WDTCR_CKS_CLK_256 | WDTCR_RPSS_100 | > + WDTCR_RPES_0 | WDTCR_TOPS_16384); > + > + rzv2h_wdt_ping(wdev); > + > + return 0; > +} > + > +static int rzv2h_wdt_stop(struct watchdog_device *wdev) > +{ > + struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev); > + > + pm_runtime_put(wdev->parent); > + reset_control_reset(priv->rstc); > + > + return 0; > +} > + > +static const struct watchdog_info rzv2h_wdt_ident = { > + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, > + .identity = "Renesas RZ/V2H WDT Watchdog", > +}; > + > +static int rzv2h_wdt_restart(struct watchdog_device *wdev, > + unsigned long action, void *data) > +{ > + rzv2h_wdt_stop(wdev); Calling pm_runtime_put() though this function may lead to unbalanced runtime PM counter if the device is not used at this moment. I may be wrong though, I'm just reading the code, anyway (see below). > + > + pm_runtime_get_sync(wdev->parent); If compiled with LOCKDEP this should trigger an invalid wait context (see commit e4cf89596c1f ("watchdog: rzg2l_wdt: Fix 'BUG: Invalid wait context'") and maybe [2] for a possible fix (if it's considered ok). [2] https://lore.kernel.org/all/20240619120920.2703605-3-claudiu.beznea.uj@bp.renesas.com/ > + > + /* > + * WDTCR > + * - CKS[7:4] - Clock Division Ratio Select - 0000b: oscclk/1 > + * - RPSS[13:12] - Window Start Position Select - 00b: 25% > + * - RPES[9:8] - Window End Position Select - 00b: 75% > + * - TOPS[1:0] - Timeout Period Select - 00b: 1024 cycles (03FFh) > + */ > + rzv2h_wdt_setup(wdev, WDTCR_CKS_CLK_1 | WDTCR_RPSS_25 | > + WDTCR_RPES_75 | WDTCR_TOPS_1024); > + > + rzv2h_wdt_ping(wdev); > + > + return 0; > +} > + > +static const struct watchdog_ops rzv2h_wdt_ops = { > + .owner = THIS_MODULE, > + .start = rzv2h_wdt_start, > + .stop = rzv2h_wdt_stop, > + .ping = rzv2h_wdt_ping, > + .restart = rzv2h_wdt_restart, > +}; > + > +static void rzv2h_wdt_reset_assert(void *data) > +{ > + struct reset_control *rstc = data; > + > + reset_control_assert(rstc); > +} > + > +static int rzv2h_wdt_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct rzv2h_wdt_priv *priv; > + struct clk *oscclk; > + unsigned long rate; > + int ret; > + > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); > + if (!priv) > + return -ENOMEM; > + > + priv->base = devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(priv->base)) > + return PTR_ERR(priv->base); > + > + /* Get watchdog oscclk clock */ > + oscclk = clk_get(&pdev->dev, "oscclk"); > + if (IS_ERR(oscclk)) > + return dev_err_probe(&pdev->dev, PTR_ERR(oscclk), > + "no oscclk"); > + > + priv->oscclk_rate = clk_get_rate(oscclk); > + clk_put(oscclk); > + if (!priv->oscclk_rate) > + return dev_err_probe(&pdev->dev, -EINVAL, "oscclk rate is 0"); > + > + priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL); > + if (IS_ERR(priv->rstc)) > + return dev_err_probe(&pdev->dev, PTR_ERR(priv->rstc), > + "failed to get cpg reset"); > + > + ret = reset_control_deassert(priv->rstc); I don't see any reason why this signal is deasserted here and then assert->deassert in stop. This may leak some power when device is not used. Is this hardware limitation ? FYI, a similar approach was implemented in rzg2l_wdt and it has been proposed for changes in [1]. [1] https://lore.kernel.org/all/20240410134044.2138310-6-claudiu.beznea.uj@bp.renesas.com/ Thank you, Claudiu Beznea > + if (ret) > + return dev_err_probe(dev, ret, "failed to deassert"); > + ret = devm_add_action_or_reset(&pdev->dev, > + rzv2h_wdt_reset_assert, > + priv->rstc); > + if (ret < 0) > + return ret; > + > + rate = priv->oscclk_rate / 256; > + priv->wdev.max_hw_heartbeat_ms = (1000 * 16383) / rate; > + dev_dbg(dev, "max hw timeout of %dms\n", > + priv->wdev.max_hw_heartbeat_ms); > + > + priv->wdev.min_timeout = 1; > + priv->wdev.timeout = WDT_DEFAULT_TIMEOUT; > + priv->wdev.info = &rzv2h_wdt_ident; > + priv->wdev.ops = &rzv2h_wdt_ops; > + priv->wdev.parent = dev; > + watchdog_set_drvdata(&priv->wdev, priv); > + watchdog_set_nowayout(&priv->wdev, nowayout); > + watchdog_stop_on_unregister(&priv->wdev); > + > + ret = watchdog_init_timeout(&priv->wdev, 0, dev); > + if (ret) > + dev_warn(dev, "Specified timeout invalid, using default"); > + > + ret = devm_pm_runtime_enable(&pdev->dev); > + if (ret) > + return ret; > + > + return devm_watchdog_register_device(&pdev->dev, &priv->wdev); > +} > + > +static const struct of_device_id rzv2h_wdt_ids[] = { > + { .compatible = "renesas,r9a09g057-wdt", }, > + { /* sentinel */ } > +}; > +MODULE_DEVICE_TABLE(of, rzv2h_wdt_ids); > + > +static struct platform_driver rzv2h_wdt_driver = { > + .driver = { > + .name = "rzv2h_wdt", > + .of_match_table = rzv2h_wdt_ids, > + }, > + .probe = rzv2h_wdt_probe, > +}; > +module_platform_driver(rzv2h_wdt_driver); > +MODULE_AUTHOR("Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>"); > +MODULE_DESCRIPTION("Renesas RZ/V2H(P) WDT Watchdog Driver");
Hi Claudiu, Thank you for the review. On Thu, Jun 20, 2024 at 8:40 AM claudiu beznea <claudiu.beznea@tuxon.dev> wrote: > > Hi, Prabhakar, > > On 19.06.2024 01:24, Prabhakar wrote: > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> > > > > Add Watchdog Timer driver for RZ/V2H(P) SoC. > > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> > > --- > > drivers/watchdog/Kconfig | 8 ++ > > drivers/watchdog/Makefile | 1 + > > drivers/watchdog/rzv2h_wdt.c | 248 +++++++++++++++++++++++++++++++++++ > > 3 files changed, 257 insertions(+) > > create mode 100644 drivers/watchdog/rzv2h_wdt.c > > > > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > > index 85eea38dbdf4..3f7bcc10ccc2 100644 > > --- a/drivers/watchdog/Kconfig > > +++ b/drivers/watchdog/Kconfig > > @@ -938,6 +938,14 @@ config RENESAS_RZG2LWDT > > This driver adds watchdog support for the integrated watchdogs in the > > Renesas RZ/G2L SoCs. These watchdogs can be used to reset a system. > > > > +config RENESAS_RZV2HWDT > > + tristate "Renesas RZ/V2H(P) WDT Watchdog" > > + depends on ARCH_RENESAS || COMPILE_TEST > > + select WATCHDOG_CORE > > + help > > + This driver adds watchdog support for the integrated watchdogs in the > > + Renesas RZ/V2H(P) SoCs. These watchdogs can be used to reset a system. > > + > > config ASPEED_WATCHDOG > > tristate "Aspeed BMC watchdog support" > > depends on ARCH_ASPEED || COMPILE_TEST > > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > > index 2d1117564f5b..295909a1b3b9 100644 > > --- a/drivers/watchdog/Makefile > > +++ b/drivers/watchdog/Makefile > > @@ -86,6 +86,7 @@ obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o > > obj-$(CONFIG_RENESAS_RZAWDT) += rza_wdt.o > > obj-$(CONFIG_RENESAS_RZN1WDT) += rzn1_wdt.o > > obj-$(CONFIG_RENESAS_RZG2LWDT) += rzg2l_wdt.o > > +obj-$(CONFIG_RENESAS_RZV2HWDT) += rzv2h_wdt.o > > obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o > > obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o > > obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o > > diff --git a/drivers/watchdog/rzv2h_wdt.c b/drivers/watchdog/rzv2h_wdt.c > > new file mode 100644 > > index 000000000000..08f97b4bab7f > > --- /dev/null > > +++ b/drivers/watchdog/rzv2h_wdt.c > > @@ -0,0 +1,248 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * Renesas RZ/V2H(P) WDT Watchdog Driver > > + * > > + * Copyright (C) 2024 Renesas Electronics Corporation. > > + */ > > +#include <linux/bitops.h> > > +#include <linux/clk.h> > > +#include <linux/delay.h> > > +#include <linux/io.h> > > +#include <linux/kernel.h> > > +#include <linux/module.h> > > +#include <linux/of.h> > > +#include <linux/platform_device.h> > > +#include <linux/pm_runtime.h> > > +#include <linux/reset.h> > > +#include <linux/units.h> > > +#include <linux/watchdog.h> > > + > > +#define WDTRR 0x00 /* RW, 8 */ > > +#define WDTCR 0x02 /* RW, 16 */ > > +#define WDTRCR 0x06 /* RW, 8 */ > > + > > +#define WDTCR_TOPS_1024 0x00 > > +#define WDTCR_TOPS_16384 0x03 > > + > > +#define WDTCR_CKS_CLK_1 0x00 > > +#define WDTCR_CKS_CLK_256 0x50 > > + > > +#define WDTCR_RPES_0 0x300 > > +#define WDTCR_RPES_75 0x000 > > + > > +#define WDTCR_RPSS_25 0x00 > > +#define WDTCR_RPSS_100 0x3000 > > + > > +#define WDTRCR_RSTIRQS BIT(7) > > + > > +#define CLOCK_DIV_BY_256 256 > > + > > +#define WDT_DEFAULT_TIMEOUT 60U > > + > > +static bool nowayout = WATCHDOG_NOWAYOUT; > > +module_param(nowayout, bool, 0); > > +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" > > + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); > > + > > +struct rzv2h_wdt_priv { > > + void __iomem *base; > > + struct watchdog_device wdev; > > + struct reset_control *rstc; > > You can keep the pointers first to save some padding, if any. > OK. > > + unsigned long oscclk_rate; > > +}; > > + > > +static u32 rzv2h_wdt_get_cycle_usec(struct rzv2h_wdt_priv *priv, > > + unsigned long cycle, > > + u16 wdttime) > > +{ > > + int clock_division_ratio; > > + u64 timer_cycle_us; > > + > > + clock_division_ratio = CLOCK_DIV_BY_256; > > + > > + timer_cycle_us = clock_division_ratio * (wdttime + 1) * MICRO; > > + > > + return div64_ul(timer_cycle_us, cycle); > > +} > > + > > +static int rzv2h_wdt_ping(struct watchdog_device *wdev) > > +{ > > + struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev); > > + unsigned long delay; > > + > > + writeb(0x0, priv->base + WDTRR); > > + writeb(0xFF, priv->base + WDTRR); > > + > > + /* > > + * Refreshing the down-counter requires up to 4 cycles > > + * of the signal for counting > > + */ > > + delay = 4 * rzv2h_wdt_get_cycle_usec(priv, priv->oscclk_rate, 0); > > + udelay(delay); > > + > > + return 0; > > +} > > + > > +static void rzv2h_wdt_setup(struct watchdog_device *wdev, u16 wdtcr) > > +{ > > + struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev); > > + > > + writew(wdtcr, priv->base + WDTCR); > > + > > + /* LSI needs RSTIRQS to be cleared */ > > + writeb(readb(priv->base + WDTRCR) & ~WDTRCR_RSTIRQS, priv->base + WDTRCR); > > +} > > + > > +static int rzv2h_wdt_start(struct watchdog_device *wdev) > > +{ > > + pm_runtime_get_sync(wdev->parent); > > You may consider using pm_runtime_resume_and_get() which takes care of > failures from __pm_runtime_resume(), if any. > OK. > > + > > + /* > > + * WDTCR > > + * - CKS[7:4] - Clock Division Ratio Select - 0101b: oscclk/256 > > + * - RPSS[13:12] - Window Start Position Select - 11b: 100% > > + * - RPES[9:8] - Window End Position Select - 11b: 0% > > + * - TOPS[1:0] - Timeout Period Select - 11b: 16384 cycles (3FFFh) > > + */ > > + rzv2h_wdt_setup(wdev, WDTCR_CKS_CLK_256 | WDTCR_RPSS_100 | > > + WDTCR_RPES_0 | WDTCR_TOPS_16384); > > + > > + rzv2h_wdt_ping(wdev); > > + > > + return 0; > > +} > > + > > +static int rzv2h_wdt_stop(struct watchdog_device *wdev) > > +{ > > + struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev); > > + > > + pm_runtime_put(wdev->parent); > > + reset_control_reset(priv->rstc); > > + > > + return 0; > > +} > > + > > +static const struct watchdog_info rzv2h_wdt_ident = { > > + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, > > + .identity = "Renesas RZ/V2H WDT Watchdog", > > +}; > > + > > +static int rzv2h_wdt_restart(struct watchdog_device *wdev, > > + unsigned long action, void *data) > > +{ > > + rzv2h_wdt_stop(wdev); > > Calling pm_runtime_put() though this function may lead to unbalanced > runtime PM counter if the device is not used at this moment. I may be wrong > though, I'm just reading the code, anyway (see below). > Agreed, I have added a check now to call stop only if WDT is active. > > + > > + pm_runtime_get_sync(wdev->parent); > > If compiled with LOCKDEP this should trigger an invalid wait context > (see commit e4cf89596c1f ("watchdog: rzg2l_wdt: Fix 'BUG: Invalid wait > context'") and maybe [2] for a possible fix (if it's considered ok). > I finally managed to replicate the issue and now replaced it with the clk_enable() api to turn ON the clocks. Cheers, Prabhakar
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 85eea38dbdf4..3f7bcc10ccc2 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -938,6 +938,14 @@ config RENESAS_RZG2LWDT This driver adds watchdog support for the integrated watchdogs in the Renesas RZ/G2L SoCs. These watchdogs can be used to reset a system. +config RENESAS_RZV2HWDT + tristate "Renesas RZ/V2H(P) WDT Watchdog" + depends on ARCH_RENESAS || COMPILE_TEST + select WATCHDOG_CORE + help + This driver adds watchdog support for the integrated watchdogs in the + Renesas RZ/V2H(P) SoCs. These watchdogs can be used to reset a system. + config ASPEED_WATCHDOG tristate "Aspeed BMC watchdog support" depends on ARCH_ASPEED || COMPILE_TEST diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index 2d1117564f5b..295909a1b3b9 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -86,6 +86,7 @@ obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o obj-$(CONFIG_RENESAS_RZAWDT) += rza_wdt.o obj-$(CONFIG_RENESAS_RZN1WDT) += rzn1_wdt.o obj-$(CONFIG_RENESAS_RZG2LWDT) += rzg2l_wdt.o +obj-$(CONFIG_RENESAS_RZV2HWDT) += rzv2h_wdt.o obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o diff --git a/drivers/watchdog/rzv2h_wdt.c b/drivers/watchdog/rzv2h_wdt.c new file mode 100644 index 000000000000..08f97b4bab7f --- /dev/null +++ b/drivers/watchdog/rzv2h_wdt.c @@ -0,0 +1,248 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Renesas RZ/V2H(P) WDT Watchdog Driver + * + * Copyright (C) 2024 Renesas Electronics Corporation. + */ +#include <linux/bitops.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/reset.h> +#include <linux/units.h> +#include <linux/watchdog.h> + +#define WDTRR 0x00 /* RW, 8 */ +#define WDTCR 0x02 /* RW, 16 */ +#define WDTRCR 0x06 /* RW, 8 */ + +#define WDTCR_TOPS_1024 0x00 +#define WDTCR_TOPS_16384 0x03 + +#define WDTCR_CKS_CLK_1 0x00 +#define WDTCR_CKS_CLK_256 0x50 + +#define WDTCR_RPES_0 0x300 +#define WDTCR_RPES_75 0x000 + +#define WDTCR_RPSS_25 0x00 +#define WDTCR_RPSS_100 0x3000 + +#define WDTRCR_RSTIRQS BIT(7) + +#define CLOCK_DIV_BY_256 256 + +#define WDT_DEFAULT_TIMEOUT 60U + +static bool nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +struct rzv2h_wdt_priv { + void __iomem *base; + struct watchdog_device wdev; + struct reset_control *rstc; + unsigned long oscclk_rate; +}; + +static u32 rzv2h_wdt_get_cycle_usec(struct rzv2h_wdt_priv *priv, + unsigned long cycle, + u16 wdttime) +{ + int clock_division_ratio; + u64 timer_cycle_us; + + clock_division_ratio = CLOCK_DIV_BY_256; + + timer_cycle_us = clock_division_ratio * (wdttime + 1) * MICRO; + + return div64_ul(timer_cycle_us, cycle); +} + +static int rzv2h_wdt_ping(struct watchdog_device *wdev) +{ + struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev); + unsigned long delay; + + writeb(0x0, priv->base + WDTRR); + writeb(0xFF, priv->base + WDTRR); + + /* + * Refreshing the down-counter requires up to 4 cycles + * of the signal for counting + */ + delay = 4 * rzv2h_wdt_get_cycle_usec(priv, priv->oscclk_rate, 0); + udelay(delay); + + return 0; +} + +static void rzv2h_wdt_setup(struct watchdog_device *wdev, u16 wdtcr) +{ + struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev); + + writew(wdtcr, priv->base + WDTCR); + + /* LSI needs RSTIRQS to be cleared */ + writeb(readb(priv->base + WDTRCR) & ~WDTRCR_RSTIRQS, priv->base + WDTRCR); +} + +static int rzv2h_wdt_start(struct watchdog_device *wdev) +{ + pm_runtime_get_sync(wdev->parent); + + /* + * WDTCR + * - CKS[7:4] - Clock Division Ratio Select - 0101b: oscclk/256 + * - RPSS[13:12] - Window Start Position Select - 11b: 100% + * - RPES[9:8] - Window End Position Select - 11b: 0% + * - TOPS[1:0] - Timeout Period Select - 11b: 16384 cycles (3FFFh) + */ + rzv2h_wdt_setup(wdev, WDTCR_CKS_CLK_256 | WDTCR_RPSS_100 | + WDTCR_RPES_0 | WDTCR_TOPS_16384); + + rzv2h_wdt_ping(wdev); + + return 0; +} + +static int rzv2h_wdt_stop(struct watchdog_device *wdev) +{ + struct rzv2h_wdt_priv *priv = watchdog_get_drvdata(wdev); + + pm_runtime_put(wdev->parent); + reset_control_reset(priv->rstc); + + return 0; +} + +static const struct watchdog_info rzv2h_wdt_ident = { + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, + .identity = "Renesas RZ/V2H WDT Watchdog", +}; + +static int rzv2h_wdt_restart(struct watchdog_device *wdev, + unsigned long action, void *data) +{ + rzv2h_wdt_stop(wdev); + + pm_runtime_get_sync(wdev->parent); + + /* + * WDTCR + * - CKS[7:4] - Clock Division Ratio Select - 0000b: oscclk/1 + * - RPSS[13:12] - Window Start Position Select - 00b: 25% + * - RPES[9:8] - Window End Position Select - 00b: 75% + * - TOPS[1:0] - Timeout Period Select - 00b: 1024 cycles (03FFh) + */ + rzv2h_wdt_setup(wdev, WDTCR_CKS_CLK_1 | WDTCR_RPSS_25 | + WDTCR_RPES_75 | WDTCR_TOPS_1024); + + rzv2h_wdt_ping(wdev); + + return 0; +} + +static const struct watchdog_ops rzv2h_wdt_ops = { + .owner = THIS_MODULE, + .start = rzv2h_wdt_start, + .stop = rzv2h_wdt_stop, + .ping = rzv2h_wdt_ping, + .restart = rzv2h_wdt_restart, +}; + +static void rzv2h_wdt_reset_assert(void *data) +{ + struct reset_control *rstc = data; + + reset_control_assert(rstc); +} + +static int rzv2h_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct rzv2h_wdt_priv *priv; + struct clk *oscclk; + unsigned long rate; + int ret; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + /* Get watchdog oscclk clock */ + oscclk = clk_get(&pdev->dev, "oscclk"); + if (IS_ERR(oscclk)) + return dev_err_probe(&pdev->dev, PTR_ERR(oscclk), + "no oscclk"); + + priv->oscclk_rate = clk_get_rate(oscclk); + clk_put(oscclk); + if (!priv->oscclk_rate) + return dev_err_probe(&pdev->dev, -EINVAL, "oscclk rate is 0"); + + priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL); + if (IS_ERR(priv->rstc)) + return dev_err_probe(&pdev->dev, PTR_ERR(priv->rstc), + "failed to get cpg reset"); + + ret = reset_control_deassert(priv->rstc); + if (ret) + return dev_err_probe(dev, ret, "failed to deassert"); + ret = devm_add_action_or_reset(&pdev->dev, + rzv2h_wdt_reset_assert, + priv->rstc); + if (ret < 0) + return ret; + + rate = priv->oscclk_rate / 256; + priv->wdev.max_hw_heartbeat_ms = (1000 * 16383) / rate; + dev_dbg(dev, "max hw timeout of %dms\n", + priv->wdev.max_hw_heartbeat_ms); + + priv->wdev.min_timeout = 1; + priv->wdev.timeout = WDT_DEFAULT_TIMEOUT; + priv->wdev.info = &rzv2h_wdt_ident; + priv->wdev.ops = &rzv2h_wdt_ops; + priv->wdev.parent = dev; + watchdog_set_drvdata(&priv->wdev, priv); + watchdog_set_nowayout(&priv->wdev, nowayout); + watchdog_stop_on_unregister(&priv->wdev); + + ret = watchdog_init_timeout(&priv->wdev, 0, dev); + if (ret) + dev_warn(dev, "Specified timeout invalid, using default"); + + ret = devm_pm_runtime_enable(&pdev->dev); + if (ret) + return ret; + + return devm_watchdog_register_device(&pdev->dev, &priv->wdev); +} + +static const struct of_device_id rzv2h_wdt_ids[] = { + { .compatible = "renesas,r9a09g057-wdt", }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, rzv2h_wdt_ids); + +static struct platform_driver rzv2h_wdt_driver = { + .driver = { + .name = "rzv2h_wdt", + .of_match_table = rzv2h_wdt_ids, + }, + .probe = rzv2h_wdt_probe, +}; +module_platform_driver(rzv2h_wdt_driver); +MODULE_AUTHOR("Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>"); +MODULE_DESCRIPTION("Renesas RZ/V2H(P) WDT Watchdog Driver");