| Message ID | 20211130161809.64591-2-sven@svenpeter.dev |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2,1/2] dt-bindings: watchdog: Add Apple Watchdog | expand |
On 2021年12月1日 1:18:09 JST, Sven Peter <sven@svenpeter.dev> wrote: >Add support for the watchdog timer found in Apple SoCs. This driver is >also required to reboot these machines. > >Signed-off-by: Sven Peter <sven@svenpeter.dev> >--- >v1 -> v2: > - set the default timeout to 30s and call watchdog_init_timeout > to allow the device tree to override it > - set WDOG_HW_RUNNING if the watchdog is enabled at boot > - check that the clock rate is not zero > - use unsigned long instead of u32 for clk_rate > - use devm_add_action_or_reset instead of manually calling > clk_disable_unprepare > - explain the magic number in apple_wdt_restart > > MAINTAINERS | 1 + > drivers/watchdog/Kconfig | 12 ++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/apple_wdt.c | 226 +++++++++++++++++++++++++++++++++++ > 4 files changed, 240 insertions(+) > create mode 100644 drivers/watchdog/apple_wdt.c > >diff --git a/MAINTAINERS b/MAINTAINERS >index 859201bbd4e8..6190f0b40983 100644 >--- a/MAINTAINERS >+++ b/MAINTAINERS >@@ -1757,6 +1757,7 @@ F: drivers/i2c/busses/i2c-pasemi-platform.c > F: drivers/irqchip/irq-apple-aic.c > F: drivers/mailbox/apple-mailbox.c > F: drivers/pinctrl/pinctrl-apple-gpio.c >+F: drivers/watchdog/apple_wdt.c > F: include/dt-bindings/interrupt-controller/apple-aic.h > F: include/dt-bindings/pinctrl/apple.h > F: include/linux/apple-mailbox.h >diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig >index 9d222ba17ec6..170dec880c8f 100644 >--- a/drivers/watchdog/Kconfig >+++ b/drivers/watchdog/Kconfig >@@ -976,6 +976,18 @@ config MSC313E_WATCHDOG > To compile this driver as a module, choose M here: the > module will be called msc313e_wdt. > >+config APPLE_WATCHDOG >+ tristate "Apple SoC watchdog" >+ depends on ARCH_APPLE || COMPILE_TEST >+ select WATCHDOG_CORE >+ help >+ Say Y here to include support for the Watchdog found in Apple >+ SoCs such as the M1. Next to the common watchdog features this >+ driver is also required in order to reboot these SoCs. >+ >+ To compile this driver as a module, choose M here: the >+ module will be called apple_wdt. >+ > # X86 (i386 + ia64 + x86_64) Architecture > > config ACQUIRE_WDT >diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile >index 2ee97064145b..270a518bd8f3 100644 >--- a/drivers/watchdog/Makefile >+++ b/drivers/watchdog/Makefile >@@ -93,6 +93,7 @@ obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o > obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o > obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o > obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o >+obj-$(CONFIG_APPLE_WATCHDOG) += apple_wdt.o > > # X86 (i386 + ia64 + x86_64) Architecture > obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o >diff --git a/drivers/watchdog/apple_wdt.c b/drivers/watchdog/apple_wdt.c >new file mode 100644 >index 000000000000..76e5bedd50d1 >--- /dev/null >+++ b/drivers/watchdog/apple_wdt.c >@@ -0,0 +1,226 @@ >+// SPDX-License-Identifier: GPL-2.0-only OR MIT >+/* >+ * Apple SoC Watchdog driver >+ * >+ * Copyright (C) The Asahi Linux Contributors >+ */ >+ >+#include <linux/bits.h> >+#include <linux/clk.h> >+#include <linux/delay.h> >+#include <linux/io.h> >+#include <linux/kernel.h> >+#include <linux/limits.h> >+#include <linux/module.h> >+#include <linux/of.h> >+#include <linux/platform_device.h> >+#include <linux/watchdog.h> >+ >+/* >+ * Apple Watchdog MMIO registers >+ * >+ * This HW block has three separate watchdogs. WD0 resets the machine >+ * to recovery mode and is not very useful for us. WD1 and WD2 trigger a normal >+ * machine reset. WD0 additionally supports a configurable interrupt. >+ * This information can be used to implement pretimeout support at a later time. >+ * >+ * APPLE_WDT_WDx_CUR_TIME is a simple counter incremented for each tick of the >+ * reference clock. It can also be overwritten to any value. >+ * Whenever APPLE_WDT_CTRL_RESET_EN is set in APPLE_WDT_WDx_CTRL and >+ * APPLE_WDTx_WD1_CUR_TIME >= APPLE_WDTx_WD1_BITE_TIME the entire machine is >+ * reset. >+ * Whenever APPLE_WDT_CTRL_IRQ_EN is set and APPLE_WDTx_WD1_CUR_TIME >= >+ * APPLE_WDTx_WD1_BARK_TIME an interrupt is triggered and >+ * APPLE_WDT_CTRL_IRQ_STATUS is set. The interrupt can be cleared by writing >+ * 1 to APPLE_WDT_CTRL_IRQ_STATUS. >+ */ >+#define APPLE_WDT_WD0_CUR_TIME 0x00 >+#define APPLE_WDT_WD0_BITE_TIME 0x04 >+#define APPLE_WDT_WD0_BARK_TIME 0x08 >+#define APPLE_WDT_WD0_CTRL 0x0c >+ >+#define APPLE_WDT_WD1_CUR_TIME 0x10 >+#define APPLE_WDT_WD1_BITE_TIME 0x14 >+#define APPLE_WDT_WD1_CTRL 0x1c >+ >+#define APPLE_WDT_WD2_CUR_TIME 0x20 >+#define APPLE_WDT_WD2_BITE_TIME 0x24 >+#define APPLE_WDT_WD2_CTRL 0x2c >+ >+#define APPLE_WDT_CTRL_IRQ_EN BIT(0) >+#define APPLE_WDT_CTRL_IRQ_STATUS BIT(1) >+#define APPLE_WDT_CTRL_RESET_EN BIT(2) >+ >+#define APPLE_WDT_TIMEOUT_DEFAULT 30 >+ >+struct apple_wdt { >+ struct watchdog_device wdd; >+ void __iomem *regs; >+ unsigned long clk_rate; >+}; >+ >+static struct apple_wdt *to_apple_wdt(struct watchdog_device *wdd) >+{ >+ return container_of(wdd, struct apple_wdt, wdd); >+} >+ >+static int apple_wdt_start(struct watchdog_device *wdd) >+{ >+ struct apple_wdt *wdt = to_apple_wdt(wdd); >+ >+ writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >+ writel_relaxed(APPLE_WDT_CTRL_RESET_EN, wdt->regs + APPLE_WDT_WD1_CTRL); >+ >+ return 0; >+} >+ >+static int apple_wdt_stop(struct watchdog_device *wdd) >+{ >+ struct apple_wdt *wdt = to_apple_wdt(wdd); >+ >+ writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CTRL); >+ >+ return 0; >+} >+ >+static int apple_wdt_ping(struct watchdog_device *wdd) >+{ >+ struct apple_wdt *wdt = to_apple_wdt(wdd); >+ >+ writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >+ >+ return 0; >+} >+ >+static int apple_wdt_set_timeout(struct watchdog_device *wdd, unsigned int s) >+{ >+ struct apple_wdt *wdt = to_apple_wdt(wdd); >+ >+ writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >+ writel_relaxed(wdt->clk_rate * s, wdt->regs + APPLE_WDT_WD1_BITE_TIME); >+ >+ wdd->timeout = s; >+ >+ return 0; >+} >+ >+static unsigned int apple_wdt_get_timeleft(struct watchdog_device *wdd) >+{ >+ struct apple_wdt *wdt = to_apple_wdt(wdd); >+ u32 cur_time, reset_time; >+ >+ cur_time = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CUR_TIME); >+ reset_time = readl_relaxed(wdt->regs + APPLE_WDT_WD1_BITE_TIME); >+ >+ return (reset_time - cur_time) / wdt->clk_rate; >+} >+ >+static int apple_wdt_restart(struct watchdog_device *wdd, unsigned long mode, >+ void *cmd) >+{ >+ struct apple_wdt *wdt = to_apple_wdt(wdd); >+ >+ writel_relaxed(APPLE_WDT_CTRL_RESET_EN, wdt->regs + APPLE_WDT_WD1_CTRL); >+ writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_BITE_TIME); >+ writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >+ >+ /* >+ * Flush writes and then wait for the SoC to reset. Even though the >+ * reset is queued almost immediately experiments have shown that it >+ * can take up to ~20-25ms until the SoC is actually reset. Just wait >+ * 50ms here to be safe. >+ */ >+ (void)readl_relaxed(wdt->regs + APPLE_WDT_WD1_CUR_TIME); >+ mdelay(50); >+ >+ return 0; >+} >+ >+static void apple_wdt_clk_disable_unprepare(void *data) >+{ >+ clk_disable_unprepare(data); >+} >+ >+static struct watchdog_ops apple_wdt_ops = { >+ .owner = THIS_MODULE, >+ .start = apple_wdt_start, >+ .stop = apple_wdt_stop, >+ .ping = apple_wdt_ping, >+ .set_timeout = apple_wdt_set_timeout, >+ .get_timeleft = apple_wdt_get_timeleft, >+ .restart = apple_wdt_restart, >+}; >+ >+static struct watchdog_info apple_wdt_info = { >+ .identity = "Apple SoC Watchdog", >+ .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, >+}; >+ >+static int apple_wdt_probe(struct platform_device *pdev) >+{ >+ struct device *dev = &pdev->dev; >+ struct apple_wdt *wdt; >+ struct clk *clk; >+ u32 wdt_ctrl; >+ int ret; >+ >+ wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); >+ if (!wdt) >+ return -ENOMEM; >+ >+ wdt->regs = devm_platform_ioremap_resource(pdev, 0); >+ if (IS_ERR(wdt->regs)) >+ return PTR_ERR(wdt->regs); >+ >+ clk = devm_clk_get(dev, NULL); >+ if (IS_ERR(clk)) >+ return PTR_ERR(clk); >+ >+ ret = clk_prepare_enable(clk); >+ if (ret) >+ return ret; >+ >+ ret = devm_add_action_or_reset(dev, apple_wdt_clk_disable_unprepare, >+ clk); >+ if (ret) >+ return ret; >+ >+ wdt->clk_rate = clk_get_rate(clk); >+ if (!wdt->clk_rate) >+ return -EINVAL; >+ >+ wdt->wdd.ops = &apple_wdt_ops; >+ wdt->wdd.info = &apple_wdt_info; >+ wdt->wdd.max_timeout = U32_MAX / wdt->clk_rate; >+ wdt->wdd.timeout = APPLE_WDT_TIMEOUT_DEFAULT; >+ >+ wdt_ctrl = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CTRL); >+ if (wdt_ctrl & APPLE_WDT_CTRL_RESET_EN) >+ set_bit(WDOG_HW_RUNNING, &wdt->wdd.status); >+ >+ watchdog_init_timeout(&wdt->wdd, 0, dev); >+ apple_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout); >+ watchdog_stop_on_unregister(&wdt->wdd); >+ watchdog_set_restart_priority(&wdt->wdd, 128); >+ >+ return devm_watchdog_register_device(dev, &wdt->wdd); >+} >+ >+static const struct of_device_id apple_wdt_of_match[] = { >+ { .compatible = "apple,wdt" }, >+ {}, >+}; >+MODULE_DEVICE_TABLE(of, apple_wdt_of_match); >+ >+static struct platform_driver apple_wdt_driver = { >+ .driver = { >+ .name = "apple-watchdog", >+ .of_match_table = apple_wdt_of_match, >+ }, >+ .probe = apple_wdt_probe, >+}; >+module_platform_driver(apple_wdt_driver); >+ >+MODULE_DESCRIPTION("Apple SoC watchdog driver"); >+MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>"); >+MODULE_LICENSE("Dual MIT/GPL"); Reviewed-by: Hector Martin <marcan@marcan.st> Thanks, looks good! Any chance you can do a quick v3 with the MAINTAINERS changes split off? As usual, I'd rather make life easier for people merging upstream :)
On 01/12/2021 01.18, Sven Peter wrote: > Add support for the watchdog timer found in Apple SoCs. This driver is > also required to reboot these machines. > > Signed-off-by: Sven Peter <sven@svenpeter.dev> > --- <snip> Tested on j274 and j314s. Feel free to add: Tested-by: Hector Martin <marcan@marcan.st>
On 12/1/21 10:44 PM, Hector Martin "marcan" wrote: > > > On 2021年12月1日 1:18:09 JST, Sven Peter <sven@svenpeter.dev> wrote: >> Add support for the watchdog timer found in Apple SoCs. This driver is >> also required to reboot these machines. >> >> Signed-off-by: Sven Peter <sven@svenpeter.dev> >> --- >> v1 -> v2: >> - set the default timeout to 30s and call watchdog_init_timeout >> to allow the device tree to override it >> - set WDOG_HW_RUNNING if the watchdog is enabled at boot >> - check that the clock rate is not zero >> - use unsigned long instead of u32 for clk_rate >> - use devm_add_action_or_reset instead of manually calling >> clk_disable_unprepare >> - explain the magic number in apple_wdt_restart >> >> MAINTAINERS | 1 + >> drivers/watchdog/Kconfig | 12 ++ >> drivers/watchdog/Makefile | 1 + >> drivers/watchdog/apple_wdt.c | 226 +++++++++++++++++++++++++++++++++++ >> 4 files changed, 240 insertions(+) >> create mode 100644 drivers/watchdog/apple_wdt.c >> >> diff --git a/MAINTAINERS b/MAINTAINERS >> index 859201bbd4e8..6190f0b40983 100644 >> --- a/MAINTAINERS >> +++ b/MAINTAINERS >> @@ -1757,6 +1757,7 @@ F: drivers/i2c/busses/i2c-pasemi-platform.c >> F: drivers/irqchip/irq-apple-aic.c >> F: drivers/mailbox/apple-mailbox.c >> F: drivers/pinctrl/pinctrl-apple-gpio.c >> +F: drivers/watchdog/apple_wdt.c >> F: include/dt-bindings/interrupt-controller/apple-aic.h >> F: include/dt-bindings/pinctrl/apple.h >> F: include/linux/apple-mailbox.h >> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig >> index 9d222ba17ec6..170dec880c8f 100644 >> --- a/drivers/watchdog/Kconfig >> +++ b/drivers/watchdog/Kconfig >> @@ -976,6 +976,18 @@ config MSC313E_WATCHDOG >> To compile this driver as a module, choose M here: the >> module will be called msc313e_wdt. >> >> +config APPLE_WATCHDOG >> + tristate "Apple SoC watchdog" >> + depends on ARCH_APPLE || COMPILE_TEST >> + select WATCHDOG_CORE >> + help >> + Say Y here to include support for the Watchdog found in Apple >> + SoCs such as the M1. Next to the common watchdog features this >> + driver is also required in order to reboot these SoCs. >> + >> + To compile this driver as a module, choose M here: the >> + module will be called apple_wdt. >> + >> # X86 (i386 + ia64 + x86_64) Architecture >> >> config ACQUIRE_WDT >> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile >> index 2ee97064145b..270a518bd8f3 100644 >> --- a/drivers/watchdog/Makefile >> +++ b/drivers/watchdog/Makefile >> @@ -93,6 +93,7 @@ obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o >> obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o >> obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o >> obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o >> +obj-$(CONFIG_APPLE_WATCHDOG) += apple_wdt.o >> >> # X86 (i386 + ia64 + x86_64) Architecture >> obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o >> diff --git a/drivers/watchdog/apple_wdt.c b/drivers/watchdog/apple_wdt.c >> new file mode 100644 >> index 000000000000..76e5bedd50d1 >> --- /dev/null >> +++ b/drivers/watchdog/apple_wdt.c >> @@ -0,0 +1,226 @@ >> +// SPDX-License-Identifier: GPL-2.0-only OR MIT >> +/* >> + * Apple SoC Watchdog driver >> + * >> + * Copyright (C) The Asahi Linux Contributors >> + */ >> + >> +#include <linux/bits.h> >> +#include <linux/clk.h> >> +#include <linux/delay.h> >> +#include <linux/io.h> >> +#include <linux/kernel.h> >> +#include <linux/limits.h> >> +#include <linux/module.h> >> +#include <linux/of.h> >> +#include <linux/platform_device.h> >> +#include <linux/watchdog.h> >> + >> +/* >> + * Apple Watchdog MMIO registers >> + * >> + * This HW block has three separate watchdogs. WD0 resets the machine >> + * to recovery mode and is not very useful for us. WD1 and WD2 trigger a normal >> + * machine reset. WD0 additionally supports a configurable interrupt. >> + * This information can be used to implement pretimeout support at a later time. >> + * >> + * APPLE_WDT_WDx_CUR_TIME is a simple counter incremented for each tick of the >> + * reference clock. It can also be overwritten to any value. >> + * Whenever APPLE_WDT_CTRL_RESET_EN is set in APPLE_WDT_WDx_CTRL and >> + * APPLE_WDTx_WD1_CUR_TIME >= APPLE_WDTx_WD1_BITE_TIME the entire machine is >> + * reset. >> + * Whenever APPLE_WDT_CTRL_IRQ_EN is set and APPLE_WDTx_WD1_CUR_TIME >= >> + * APPLE_WDTx_WD1_BARK_TIME an interrupt is triggered and >> + * APPLE_WDT_CTRL_IRQ_STATUS is set. The interrupt can be cleared by writing >> + * 1 to APPLE_WDT_CTRL_IRQ_STATUS. >> + */ >> +#define APPLE_WDT_WD0_CUR_TIME 0x00 >> +#define APPLE_WDT_WD0_BITE_TIME 0x04 >> +#define APPLE_WDT_WD0_BARK_TIME 0x08 >> +#define APPLE_WDT_WD0_CTRL 0x0c >> + >> +#define APPLE_WDT_WD1_CUR_TIME 0x10 >> +#define APPLE_WDT_WD1_BITE_TIME 0x14 >> +#define APPLE_WDT_WD1_CTRL 0x1c >> + >> +#define APPLE_WDT_WD2_CUR_TIME 0x20 >> +#define APPLE_WDT_WD2_BITE_TIME 0x24 >> +#define APPLE_WDT_WD2_CTRL 0x2c >> + >> +#define APPLE_WDT_CTRL_IRQ_EN BIT(0) >> +#define APPLE_WDT_CTRL_IRQ_STATUS BIT(1) >> +#define APPLE_WDT_CTRL_RESET_EN BIT(2) >> + >> +#define APPLE_WDT_TIMEOUT_DEFAULT 30 >> + >> +struct apple_wdt { >> + struct watchdog_device wdd; >> + void __iomem *regs; >> + unsigned long clk_rate; >> +}; >> + >> +static struct apple_wdt *to_apple_wdt(struct watchdog_device *wdd) >> +{ >> + return container_of(wdd, struct apple_wdt, wdd); >> +} >> + >> +static int apple_wdt_start(struct watchdog_device *wdd) >> +{ >> + struct apple_wdt *wdt = to_apple_wdt(wdd); >> + >> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >> + writel_relaxed(APPLE_WDT_CTRL_RESET_EN, wdt->regs + APPLE_WDT_WD1_CTRL); >> + >> + return 0; >> +} >> + >> +static int apple_wdt_stop(struct watchdog_device *wdd) >> +{ >> + struct apple_wdt *wdt = to_apple_wdt(wdd); >> + >> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CTRL); >> + >> + return 0; >> +} >> + >> +static int apple_wdt_ping(struct watchdog_device *wdd) >> +{ >> + struct apple_wdt *wdt = to_apple_wdt(wdd); >> + >> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >> + >> + return 0; >> +} >> + >> +static int apple_wdt_set_timeout(struct watchdog_device *wdd, unsigned int s) >> +{ >> + struct apple_wdt *wdt = to_apple_wdt(wdd); >> + >> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >> + writel_relaxed(wdt->clk_rate * s, wdt->regs + APPLE_WDT_WD1_BITE_TIME); >> + >> + wdd->timeout = s; >> + >> + return 0; >> +} >> + >> +static unsigned int apple_wdt_get_timeleft(struct watchdog_device *wdd) >> +{ >> + struct apple_wdt *wdt = to_apple_wdt(wdd); >> + u32 cur_time, reset_time; >> + >> + cur_time = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CUR_TIME); >> + reset_time = readl_relaxed(wdt->regs + APPLE_WDT_WD1_BITE_TIME); >> + >> + return (reset_time - cur_time) / wdt->clk_rate; >> +} >> + >> +static int apple_wdt_restart(struct watchdog_device *wdd, unsigned long mode, >> + void *cmd) >> +{ >> + struct apple_wdt *wdt = to_apple_wdt(wdd); >> + >> + writel_relaxed(APPLE_WDT_CTRL_RESET_EN, wdt->regs + APPLE_WDT_WD1_CTRL); >> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_BITE_TIME); >> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >> + >> + /* >> + * Flush writes and then wait for the SoC to reset. Even though the >> + * reset is queued almost immediately experiments have shown that it >> + * can take up to ~20-25ms until the SoC is actually reset. Just wait >> + * 50ms here to be safe. >> + */ >> + (void)readl_relaxed(wdt->regs + APPLE_WDT_WD1_CUR_TIME); >> + mdelay(50); >> + >> + return 0; >> +} >> + >> +static void apple_wdt_clk_disable_unprepare(void *data) >> +{ >> + clk_disable_unprepare(data); >> +} >> + >> +static struct watchdog_ops apple_wdt_ops = { >> + .owner = THIS_MODULE, >> + .start = apple_wdt_start, >> + .stop = apple_wdt_stop, >> + .ping = apple_wdt_ping, >> + .set_timeout = apple_wdt_set_timeout, >> + .get_timeleft = apple_wdt_get_timeleft, >> + .restart = apple_wdt_restart, >> +}; >> + >> +static struct watchdog_info apple_wdt_info = { >> + .identity = "Apple SoC Watchdog", >> + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, >> +}; >> + >> +static int apple_wdt_probe(struct platform_device *pdev) >> +{ >> + struct device *dev = &pdev->dev; >> + struct apple_wdt *wdt; >> + struct clk *clk; >> + u32 wdt_ctrl; >> + int ret; >> + >> + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); >> + if (!wdt) >> + return -ENOMEM; >> + >> + wdt->regs = devm_platform_ioremap_resource(pdev, 0); >> + if (IS_ERR(wdt->regs)) >> + return PTR_ERR(wdt->regs); >> + >> + clk = devm_clk_get(dev, NULL); >> + if (IS_ERR(clk)) >> + return PTR_ERR(clk); >> + >> + ret = clk_prepare_enable(clk); >> + if (ret) >> + return ret; >> + >> + ret = devm_add_action_or_reset(dev, apple_wdt_clk_disable_unprepare, >> + clk); >> + if (ret) >> + return ret; >> + >> + wdt->clk_rate = clk_get_rate(clk); >> + if (!wdt->clk_rate) >> + return -EINVAL; >> + >> + wdt->wdd.ops = &apple_wdt_ops; >> + wdt->wdd.info = &apple_wdt_info; >> + wdt->wdd.max_timeout = U32_MAX / wdt->clk_rate; >> + wdt->wdd.timeout = APPLE_WDT_TIMEOUT_DEFAULT; >> + >> + wdt_ctrl = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CTRL); >> + if (wdt_ctrl & APPLE_WDT_CTRL_RESET_EN) >> + set_bit(WDOG_HW_RUNNING, &wdt->wdd.status); >> + >> + watchdog_init_timeout(&wdt->wdd, 0, dev); >> + apple_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout); >> + watchdog_stop_on_unregister(&wdt->wdd); >> + watchdog_set_restart_priority(&wdt->wdd, 128); >> + >> + return devm_watchdog_register_device(dev, &wdt->wdd); >> +} >> + >> +static const struct of_device_id apple_wdt_of_match[] = { >> + { .compatible = "apple,wdt" }, >> + {}, >> +}; >> +MODULE_DEVICE_TABLE(of, apple_wdt_of_match); >> + >> +static struct platform_driver apple_wdt_driver = { >> + .driver = { >> + .name = "apple-watchdog", >> + .of_match_table = apple_wdt_of_match, >> + }, >> + .probe = apple_wdt_probe, >> +}; >> +module_platform_driver(apple_wdt_driver); >> + >> +MODULE_DESCRIPTION("Apple SoC watchdog driver"); >> +MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>"); >> +MODULE_LICENSE("Dual MIT/GPL"); > > Reviewed-by: Hector Martin <marcan@marcan.st> > > Thanks, looks good! Any chance you can do a quick v3 with the MAINTAINERS changes split off? As usual, I'd rather make life easier for people merging upstream :) > Usually I don't ask for such a split, and I don't recall that being an issue. So, from my perspective, that is not necessary. Guenter
On Tue, Nov 30, 2021 at 05:18:09PM +0100, Sven Peter wrote: > Add support for the watchdog timer found in Apple SoCs. This driver is > also required to reboot these machines. > > Signed-off-by: Sven Peter <sven@svenpeter.dev> Reviewed-by: Guenter Roeck <linux@roeck-us.net> > --- > v1 -> v2: > - set the default timeout to 30s and call watchdog_init_timeout > to allow the device tree to override it > - set WDOG_HW_RUNNING if the watchdog is enabled at boot > - check that the clock rate is not zero > - use unsigned long instead of u32 for clk_rate > - use devm_add_action_or_reset instead of manually calling > clk_disable_unprepare > - explain the magic number in apple_wdt_restart > > MAINTAINERS | 1 + > drivers/watchdog/Kconfig | 12 ++ > drivers/watchdog/Makefile | 1 + > drivers/watchdog/apple_wdt.c | 226 +++++++++++++++++++++++++++++++++++ > 4 files changed, 240 insertions(+) > create mode 100644 drivers/watchdog/apple_wdt.c > > diff --git a/MAINTAINERS b/MAINTAINERS > index 859201bbd4e8..6190f0b40983 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -1757,6 +1757,7 @@ F: drivers/i2c/busses/i2c-pasemi-platform.c > F: drivers/irqchip/irq-apple-aic.c > F: drivers/mailbox/apple-mailbox.c > F: drivers/pinctrl/pinctrl-apple-gpio.c > +F: drivers/watchdog/apple_wdt.c > F: include/dt-bindings/interrupt-controller/apple-aic.h > F: include/dt-bindings/pinctrl/apple.h > F: include/linux/apple-mailbox.h > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index 9d222ba17ec6..170dec880c8f 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -976,6 +976,18 @@ config MSC313E_WATCHDOG > To compile this driver as a module, choose M here: the > module will be called msc313e_wdt. > > +config APPLE_WATCHDOG > + tristate "Apple SoC watchdog" > + depends on ARCH_APPLE || COMPILE_TEST > + select WATCHDOG_CORE > + help > + Say Y here to include support for the Watchdog found in Apple > + SoCs such as the M1. Next to the common watchdog features this > + driver is also required in order to reboot these SoCs. > + > + To compile this driver as a module, choose M here: the > + module will be called apple_wdt. > + > # X86 (i386 + ia64 + x86_64) Architecture > > config ACQUIRE_WDT > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index 2ee97064145b..270a518bd8f3 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -93,6 +93,7 @@ obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o > obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o > obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o > obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o > +obj-$(CONFIG_APPLE_WATCHDOG) += apple_wdt.o > > # X86 (i386 + ia64 + x86_64) Architecture > obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o > diff --git a/drivers/watchdog/apple_wdt.c b/drivers/watchdog/apple_wdt.c > new file mode 100644 > index 000000000000..76e5bedd50d1 > --- /dev/null > +++ b/drivers/watchdog/apple_wdt.c > @@ -0,0 +1,226 @@ > +// SPDX-License-Identifier: GPL-2.0-only OR MIT > +/* > + * Apple SoC Watchdog driver > + * > + * Copyright (C) The Asahi Linux Contributors > + */ > + > +#include <linux/bits.h> > +#include <linux/clk.h> > +#include <linux/delay.h> > +#include <linux/io.h> > +#include <linux/kernel.h> > +#include <linux/limits.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/platform_device.h> > +#include <linux/watchdog.h> > + > +/* > + * Apple Watchdog MMIO registers > + * > + * This HW block has three separate watchdogs. WD0 resets the machine > + * to recovery mode and is not very useful for us. WD1 and WD2 trigger a normal > + * machine reset. WD0 additionally supports a configurable interrupt. > + * This information can be used to implement pretimeout support at a later time. > + * > + * APPLE_WDT_WDx_CUR_TIME is a simple counter incremented for each tick of the > + * reference clock. It can also be overwritten to any value. > + * Whenever APPLE_WDT_CTRL_RESET_EN is set in APPLE_WDT_WDx_CTRL and > + * APPLE_WDTx_WD1_CUR_TIME >= APPLE_WDTx_WD1_BITE_TIME the entire machine is > + * reset. > + * Whenever APPLE_WDT_CTRL_IRQ_EN is set and APPLE_WDTx_WD1_CUR_TIME >= > + * APPLE_WDTx_WD1_BARK_TIME an interrupt is triggered and > + * APPLE_WDT_CTRL_IRQ_STATUS is set. The interrupt can be cleared by writing > + * 1 to APPLE_WDT_CTRL_IRQ_STATUS. > + */ > +#define APPLE_WDT_WD0_CUR_TIME 0x00 > +#define APPLE_WDT_WD0_BITE_TIME 0x04 > +#define APPLE_WDT_WD0_BARK_TIME 0x08 > +#define APPLE_WDT_WD0_CTRL 0x0c > + > +#define APPLE_WDT_WD1_CUR_TIME 0x10 > +#define APPLE_WDT_WD1_BITE_TIME 0x14 > +#define APPLE_WDT_WD1_CTRL 0x1c > + > +#define APPLE_WDT_WD2_CUR_TIME 0x20 > +#define APPLE_WDT_WD2_BITE_TIME 0x24 > +#define APPLE_WDT_WD2_CTRL 0x2c > + > +#define APPLE_WDT_CTRL_IRQ_EN BIT(0) > +#define APPLE_WDT_CTRL_IRQ_STATUS BIT(1) > +#define APPLE_WDT_CTRL_RESET_EN BIT(2) > + > +#define APPLE_WDT_TIMEOUT_DEFAULT 30 > + > +struct apple_wdt { > + struct watchdog_device wdd; > + void __iomem *regs; > + unsigned long clk_rate; > +}; > + > +static struct apple_wdt *to_apple_wdt(struct watchdog_device *wdd) > +{ > + return container_of(wdd, struct apple_wdt, wdd); > +} > + > +static int apple_wdt_start(struct watchdog_device *wdd) > +{ > + struct apple_wdt *wdt = to_apple_wdt(wdd); > + > + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); > + writel_relaxed(APPLE_WDT_CTRL_RESET_EN, wdt->regs + APPLE_WDT_WD1_CTRL); > + > + return 0; > +} > + > +static int apple_wdt_stop(struct watchdog_device *wdd) > +{ > + struct apple_wdt *wdt = to_apple_wdt(wdd); > + > + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CTRL); > + > + return 0; > +} > + > +static int apple_wdt_ping(struct watchdog_device *wdd) > +{ > + struct apple_wdt *wdt = to_apple_wdt(wdd); > + > + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); > + > + return 0; > +} > + > +static int apple_wdt_set_timeout(struct watchdog_device *wdd, unsigned int s) > +{ > + struct apple_wdt *wdt = to_apple_wdt(wdd); > + > + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); > + writel_relaxed(wdt->clk_rate * s, wdt->regs + APPLE_WDT_WD1_BITE_TIME); > + > + wdd->timeout = s; > + > + return 0; > +} > + > +static unsigned int apple_wdt_get_timeleft(struct watchdog_device *wdd) > +{ > + struct apple_wdt *wdt = to_apple_wdt(wdd); > + u32 cur_time, reset_time; > + > + cur_time = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CUR_TIME); > + reset_time = readl_relaxed(wdt->regs + APPLE_WDT_WD1_BITE_TIME); > + > + return (reset_time - cur_time) / wdt->clk_rate; > +} > + > +static int apple_wdt_restart(struct watchdog_device *wdd, unsigned long mode, > + void *cmd) > +{ > + struct apple_wdt *wdt = to_apple_wdt(wdd); > + > + writel_relaxed(APPLE_WDT_CTRL_RESET_EN, wdt->regs + APPLE_WDT_WD1_CTRL); > + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_BITE_TIME); > + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); > + > + /* > + * Flush writes and then wait for the SoC to reset. Even though the > + * reset is queued almost immediately experiments have shown that it > + * can take up to ~20-25ms until the SoC is actually reset. Just wait > + * 50ms here to be safe. > + */ > + (void)readl_relaxed(wdt->regs + APPLE_WDT_WD1_CUR_TIME); > + mdelay(50); > + > + return 0; > +} > + > +static void apple_wdt_clk_disable_unprepare(void *data) > +{ > + clk_disable_unprepare(data); > +} > + > +static struct watchdog_ops apple_wdt_ops = { > + .owner = THIS_MODULE, > + .start = apple_wdt_start, > + .stop = apple_wdt_stop, > + .ping = apple_wdt_ping, > + .set_timeout = apple_wdt_set_timeout, > + .get_timeleft = apple_wdt_get_timeleft, > + .restart = apple_wdt_restart, > +}; > + > +static struct watchdog_info apple_wdt_info = { > + .identity = "Apple SoC Watchdog", > + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, > +}; > + > +static int apple_wdt_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct apple_wdt *wdt; > + struct clk *clk; > + u32 wdt_ctrl; > + int ret; > + > + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); > + if (!wdt) > + return -ENOMEM; > + > + wdt->regs = devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(wdt->regs)) > + return PTR_ERR(wdt->regs); > + > + clk = devm_clk_get(dev, NULL); > + if (IS_ERR(clk)) > + return PTR_ERR(clk); > + > + ret = clk_prepare_enable(clk); > + if (ret) > + return ret; > + > + ret = devm_add_action_or_reset(dev, apple_wdt_clk_disable_unprepare, > + clk); > + if (ret) > + return ret; > + > + wdt->clk_rate = clk_get_rate(clk); > + if (!wdt->clk_rate) > + return -EINVAL; > + > + wdt->wdd.ops = &apple_wdt_ops; > + wdt->wdd.info = &apple_wdt_info; > + wdt->wdd.max_timeout = U32_MAX / wdt->clk_rate; > + wdt->wdd.timeout = APPLE_WDT_TIMEOUT_DEFAULT; > + > + wdt_ctrl = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CTRL); > + if (wdt_ctrl & APPLE_WDT_CTRL_RESET_EN) > + set_bit(WDOG_HW_RUNNING, &wdt->wdd.status); > + > + watchdog_init_timeout(&wdt->wdd, 0, dev); > + apple_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout); > + watchdog_stop_on_unregister(&wdt->wdd); > + watchdog_set_restart_priority(&wdt->wdd, 128); > + > + return devm_watchdog_register_device(dev, &wdt->wdd); > +} > + > +static const struct of_device_id apple_wdt_of_match[] = { > + { .compatible = "apple,wdt" }, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, apple_wdt_of_match); > + > +static struct platform_driver apple_wdt_driver = { > + .driver = { > + .name = "apple-watchdog", > + .of_match_table = apple_wdt_of_match, > + }, > + .probe = apple_wdt_probe, > +}; > +module_platform_driver(apple_wdt_driver); > + > +MODULE_DESCRIPTION("Apple SoC watchdog driver"); > +MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>"); > +MODULE_LICENSE("Dual MIT/GPL"); > -- > 2.25.1 >
On 02/12/2021 23.36, Guenter Roeck wrote: > On 12/1/21 10:44 PM, Hector Martin "marcan" wrote: >> >> >> On 2021年12月1日 1:18:09 JST, Sven Peter <sven@svenpeter.dev> wrote: >>> Add support for the watchdog timer found in Apple SoCs. This driver is >>> also required to reboot these machines. >>> >>> Signed-off-by: Sven Peter <sven@svenpeter.dev> >>> --- >>> v1 -> v2: >>> - set the default timeout to 30s and call watchdog_init_timeout >>> to allow the device tree to override it >>> - set WDOG_HW_RUNNING if the watchdog is enabled at boot >>> - check that the clock rate is not zero >>> - use unsigned long instead of u32 for clk_rate >>> - use devm_add_action_or_reset instead of manually calling >>> clk_disable_unprepare >>> - explain the magic number in apple_wdt_restart >>> >>> MAINTAINERS | 1 + >>> drivers/watchdog/Kconfig | 12 ++ >>> drivers/watchdog/Makefile | 1 + >>> drivers/watchdog/apple_wdt.c | 226 +++++++++++++++++++++++++++++++++++ >>> 4 files changed, 240 insertions(+) >>> create mode 100644 drivers/watchdog/apple_wdt.c >>> >>> diff --git a/MAINTAINERS b/MAINTAINERS >>> index 859201bbd4e8..6190f0b40983 100644 >>> --- a/MAINTAINERS >>> +++ b/MAINTAINERS >>> @@ -1757,6 +1757,7 @@ F: drivers/i2c/busses/i2c-pasemi-platform.c >>> F: drivers/irqchip/irq-apple-aic.c >>> F: drivers/mailbox/apple-mailbox.c >>> F: drivers/pinctrl/pinctrl-apple-gpio.c >>> +F: drivers/watchdog/apple_wdt.c >>> F: include/dt-bindings/interrupt-controller/apple-aic.h >>> F: include/dt-bindings/pinctrl/apple.h >>> F: include/linux/apple-mailbox.h >>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig >>> index 9d222ba17ec6..170dec880c8f 100644 >>> --- a/drivers/watchdog/Kconfig >>> +++ b/drivers/watchdog/Kconfig >>> @@ -976,6 +976,18 @@ config MSC313E_WATCHDOG >>> To compile this driver as a module, choose M here: the >>> module will be called msc313e_wdt. >>> >>> +config APPLE_WATCHDOG >>> + tristate "Apple SoC watchdog" >>> + depends on ARCH_APPLE || COMPILE_TEST >>> + select WATCHDOG_CORE >>> + help >>> + Say Y here to include support for the Watchdog found in Apple >>> + SoCs such as the M1. Next to the common watchdog features this >>> + driver is also required in order to reboot these SoCs. >>> + >>> + To compile this driver as a module, choose M here: the >>> + module will be called apple_wdt. >>> + >>> # X86 (i386 + ia64 + x86_64) Architecture >>> >>> config ACQUIRE_WDT >>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile >>> index 2ee97064145b..270a518bd8f3 100644 >>> --- a/drivers/watchdog/Makefile >>> +++ b/drivers/watchdog/Makefile >>> @@ -93,6 +93,7 @@ obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o >>> obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o >>> obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o >>> obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o >>> +obj-$(CONFIG_APPLE_WATCHDOG) += apple_wdt.o >>> >>> # X86 (i386 + ia64 + x86_64) Architecture >>> obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o >>> diff --git a/drivers/watchdog/apple_wdt.c b/drivers/watchdog/apple_wdt.c >>> new file mode 100644 >>> index 000000000000..76e5bedd50d1 >>> --- /dev/null >>> +++ b/drivers/watchdog/apple_wdt.c >>> @@ -0,0 +1,226 @@ >>> +// SPDX-License-Identifier: GPL-2.0-only OR MIT >>> +/* >>> + * Apple SoC Watchdog driver >>> + * >>> + * Copyright (C) The Asahi Linux Contributors >>> + */ >>> + >>> +#include <linux/bits.h> >>> +#include <linux/clk.h> >>> +#include <linux/delay.h> >>> +#include <linux/io.h> >>> +#include <linux/kernel.h> >>> +#include <linux/limits.h> >>> +#include <linux/module.h> >>> +#include <linux/of.h> >>> +#include <linux/platform_device.h> >>> +#include <linux/watchdog.h> >>> + >>> +/* >>> + * Apple Watchdog MMIO registers >>> + * >>> + * This HW block has three separate watchdogs. WD0 resets the machine >>> + * to recovery mode and is not very useful for us. WD1 and WD2 trigger a normal >>> + * machine reset. WD0 additionally supports a configurable interrupt. >>> + * This information can be used to implement pretimeout support at a later time. >>> + * >>> + * APPLE_WDT_WDx_CUR_TIME is a simple counter incremented for each tick of the >>> + * reference clock. It can also be overwritten to any value. >>> + * Whenever APPLE_WDT_CTRL_RESET_EN is set in APPLE_WDT_WDx_CTRL and >>> + * APPLE_WDTx_WD1_CUR_TIME >= APPLE_WDTx_WD1_BITE_TIME the entire machine is >>> + * reset. >>> + * Whenever APPLE_WDT_CTRL_IRQ_EN is set and APPLE_WDTx_WD1_CUR_TIME >= >>> + * APPLE_WDTx_WD1_BARK_TIME an interrupt is triggered and >>> + * APPLE_WDT_CTRL_IRQ_STATUS is set. The interrupt can be cleared by writing >>> + * 1 to APPLE_WDT_CTRL_IRQ_STATUS. >>> + */ >>> +#define APPLE_WDT_WD0_CUR_TIME 0x00 >>> +#define APPLE_WDT_WD0_BITE_TIME 0x04 >>> +#define APPLE_WDT_WD0_BARK_TIME 0x08 >>> +#define APPLE_WDT_WD0_CTRL 0x0c >>> + >>> +#define APPLE_WDT_WD1_CUR_TIME 0x10 >>> +#define APPLE_WDT_WD1_BITE_TIME 0x14 >>> +#define APPLE_WDT_WD1_CTRL 0x1c >>> + >>> +#define APPLE_WDT_WD2_CUR_TIME 0x20 >>> +#define APPLE_WDT_WD2_BITE_TIME 0x24 >>> +#define APPLE_WDT_WD2_CTRL 0x2c >>> + >>> +#define APPLE_WDT_CTRL_IRQ_EN BIT(0) >>> +#define APPLE_WDT_CTRL_IRQ_STATUS BIT(1) >>> +#define APPLE_WDT_CTRL_RESET_EN BIT(2) >>> + >>> +#define APPLE_WDT_TIMEOUT_DEFAULT 30 >>> + >>> +struct apple_wdt { >>> + struct watchdog_device wdd; >>> + void __iomem *regs; >>> + unsigned long clk_rate; >>> +}; >>> + >>> +static struct apple_wdt *to_apple_wdt(struct watchdog_device *wdd) >>> +{ >>> + return container_of(wdd, struct apple_wdt, wdd); >>> +} >>> + >>> +static int apple_wdt_start(struct watchdog_device *wdd) >>> +{ >>> + struct apple_wdt *wdt = to_apple_wdt(wdd); >>> + >>> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >>> + writel_relaxed(APPLE_WDT_CTRL_RESET_EN, wdt->regs + APPLE_WDT_WD1_CTRL); >>> + >>> + return 0; >>> +} >>> + >>> +static int apple_wdt_stop(struct watchdog_device *wdd) >>> +{ >>> + struct apple_wdt *wdt = to_apple_wdt(wdd); >>> + >>> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CTRL); >>> + >>> + return 0; >>> +} >>> + >>> +static int apple_wdt_ping(struct watchdog_device *wdd) >>> +{ >>> + struct apple_wdt *wdt = to_apple_wdt(wdd); >>> + >>> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >>> + >>> + return 0; >>> +} >>> + >>> +static int apple_wdt_set_timeout(struct watchdog_device *wdd, unsigned int s) >>> +{ >>> + struct apple_wdt *wdt = to_apple_wdt(wdd); >>> + >>> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >>> + writel_relaxed(wdt->clk_rate * s, wdt->regs + APPLE_WDT_WD1_BITE_TIME); >>> + >>> + wdd->timeout = s; >>> + >>> + return 0; >>> +} >>> + >>> +static unsigned int apple_wdt_get_timeleft(struct watchdog_device *wdd) >>> +{ >>> + struct apple_wdt *wdt = to_apple_wdt(wdd); >>> + u32 cur_time, reset_time; >>> + >>> + cur_time = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CUR_TIME); >>> + reset_time = readl_relaxed(wdt->regs + APPLE_WDT_WD1_BITE_TIME); >>> + >>> + return (reset_time - cur_time) / wdt->clk_rate; >>> +} >>> + >>> +static int apple_wdt_restart(struct watchdog_device *wdd, unsigned long mode, >>> + void *cmd) >>> +{ >>> + struct apple_wdt *wdt = to_apple_wdt(wdd); >>> + >>> + writel_relaxed(APPLE_WDT_CTRL_RESET_EN, wdt->regs + APPLE_WDT_WD1_CTRL); >>> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_BITE_TIME); >>> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >>> + >>> + /* >>> + * Flush writes and then wait for the SoC to reset. Even though the >>> + * reset is queued almost immediately experiments have shown that it >>> + * can take up to ~20-25ms until the SoC is actually reset. Just wait >>> + * 50ms here to be safe. >>> + */ >>> + (void)readl_relaxed(wdt->regs + APPLE_WDT_WD1_CUR_TIME); >>> + mdelay(50); >>> + >>> + return 0; >>> +} >>> + >>> +static void apple_wdt_clk_disable_unprepare(void *data) >>> +{ >>> + clk_disable_unprepare(data); >>> +} >>> + >>> +static struct watchdog_ops apple_wdt_ops = { >>> + .owner = THIS_MODULE, >>> + .start = apple_wdt_start, >>> + .stop = apple_wdt_stop, >>> + .ping = apple_wdt_ping, >>> + .set_timeout = apple_wdt_set_timeout, >>> + .get_timeleft = apple_wdt_get_timeleft, >>> + .restart = apple_wdt_restart, >>> +}; >>> + >>> +static struct watchdog_info apple_wdt_info = { >>> + .identity = "Apple SoC Watchdog", >>> + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, >>> +}; >>> + >>> +static int apple_wdt_probe(struct platform_device *pdev) >>> +{ >>> + struct device *dev = &pdev->dev; >>> + struct apple_wdt *wdt; >>> + struct clk *clk; >>> + u32 wdt_ctrl; >>> + int ret; >>> + >>> + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); >>> + if (!wdt) >>> + return -ENOMEM; >>> + >>> + wdt->regs = devm_platform_ioremap_resource(pdev, 0); >>> + if (IS_ERR(wdt->regs)) >>> + return PTR_ERR(wdt->regs); >>> + >>> + clk = devm_clk_get(dev, NULL); >>> + if (IS_ERR(clk)) >>> + return PTR_ERR(clk); >>> + >>> + ret = clk_prepare_enable(clk); >>> + if (ret) >>> + return ret; >>> + >>> + ret = devm_add_action_or_reset(dev, apple_wdt_clk_disable_unprepare, >>> + clk); >>> + if (ret) >>> + return ret; >>> + >>> + wdt->clk_rate = clk_get_rate(clk); >>> + if (!wdt->clk_rate) >>> + return -EINVAL; >>> + >>> + wdt->wdd.ops = &apple_wdt_ops; >>> + wdt->wdd.info = &apple_wdt_info; >>> + wdt->wdd.max_timeout = U32_MAX / wdt->clk_rate; >>> + wdt->wdd.timeout = APPLE_WDT_TIMEOUT_DEFAULT; >>> + >>> + wdt_ctrl = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CTRL); >>> + if (wdt_ctrl & APPLE_WDT_CTRL_RESET_EN) >>> + set_bit(WDOG_HW_RUNNING, &wdt->wdd.status); >>> + >>> + watchdog_init_timeout(&wdt->wdd, 0, dev); >>> + apple_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout); >>> + watchdog_stop_on_unregister(&wdt->wdd); >>> + watchdog_set_restart_priority(&wdt->wdd, 128); >>> + >>> + return devm_watchdog_register_device(dev, &wdt->wdd); >>> +} >>> + >>> +static const struct of_device_id apple_wdt_of_match[] = { >>> + { .compatible = "apple,wdt" }, >>> + {}, >>> +}; >>> +MODULE_DEVICE_TABLE(of, apple_wdt_of_match); >>> + >>> +static struct platform_driver apple_wdt_driver = { >>> + .driver = { >>> + .name = "apple-watchdog", >>> + .of_match_table = apple_wdt_of_match, >>> + }, >>> + .probe = apple_wdt_probe, >>> +}; >>> +module_platform_driver(apple_wdt_driver); >>> + >>> +MODULE_DESCRIPTION("Apple SoC watchdog driver"); >>> +MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>"); >>> +MODULE_LICENSE("Dual MIT/GPL"); >> >> Reviewed-by: Hector Martin <marcan@marcan.st> >> >> Thanks, looks good! Any chance you can do a quick v3 with the MAINTAINERS changes split off? As usual, I'd rather make life easier for people merging upstream :) >> > > Usually I don't ask for such a split, and I don't recall that being an issue. > So, from my perspective, that is not necessary. We're upstreaming a bunch of things in parallel that touch the same MAINTAINERS section, and if each of those goes through subsystem trees, they all end up creating a pile of conflicts when merged. This has already happened a few times (I got a ping from linux-next about it the other day). To make life easier for upstream mergers, we prefer to split off MAINTAINERS changes. Then instead of going through the subsystem tree, I can push those up through the SoC tree, making sure to resolve any conflicts/ordering issues. Then everyone upstream of us is happy :-)
On 12/3/21 5:50 AM, Hector Martin wrote: > On 02/12/2021 23.36, Guenter Roeck wrote: >> On 12/1/21 10:44 PM, Hector Martin "marcan" wrote: >>> >>> >>> On 2021年12月1日 1:18:09 JST, Sven Peter <sven@svenpeter.dev> wrote: >>>> Add support for the watchdog timer found in Apple SoCs. This driver is >>>> also required to reboot these machines. >>>> >>>> Signed-off-by: Sven Peter <sven@svenpeter.dev> >>>> --- >>>> v1 -> v2: >>>> - set the default timeout to 30s and call watchdog_init_timeout >>>> to allow the device tree to override it >>>> - set WDOG_HW_RUNNING if the watchdog is enabled at boot >>>> - check that the clock rate is not zero >>>> - use unsigned long instead of u32 for clk_rate >>>> - use devm_add_action_or_reset instead of manually calling >>>> clk_disable_unprepare >>>> - explain the magic number in apple_wdt_restart >>>> >>>> MAINTAINERS | 1 + >>>> drivers/watchdog/Kconfig | 12 ++ >>>> drivers/watchdog/Makefile | 1 + >>>> drivers/watchdog/apple_wdt.c | 226 +++++++++++++++++++++++++++++++++++ >>>> 4 files changed, 240 insertions(+) >>>> create mode 100644 drivers/watchdog/apple_wdt.c >>>> >>>> diff --git a/MAINTAINERS b/MAINTAINERS >>>> index 859201bbd4e8..6190f0b40983 100644 >>>> --- a/MAINTAINERS >>>> +++ b/MAINTAINERS >>>> @@ -1757,6 +1757,7 @@ F: drivers/i2c/busses/i2c-pasemi-platform.c >>>> F: drivers/irqchip/irq-apple-aic.c >>>> F: drivers/mailbox/apple-mailbox.c >>>> F: drivers/pinctrl/pinctrl-apple-gpio.c >>>> +F: drivers/watchdog/apple_wdt.c >>>> F: include/dt-bindings/interrupt-controller/apple-aic.h >>>> F: include/dt-bindings/pinctrl/apple.h >>>> F: include/linux/apple-mailbox.h >>>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig >>>> index 9d222ba17ec6..170dec880c8f 100644 >>>> --- a/drivers/watchdog/Kconfig >>>> +++ b/drivers/watchdog/Kconfig >>>> @@ -976,6 +976,18 @@ config MSC313E_WATCHDOG >>>> To compile this driver as a module, choose M here: the >>>> module will be called msc313e_wdt. >>>> >>>> +config APPLE_WATCHDOG >>>> + tristate "Apple SoC watchdog" >>>> + depends on ARCH_APPLE || COMPILE_TEST >>>> + select WATCHDOG_CORE >>>> + help >>>> + Say Y here to include support for the Watchdog found in Apple >>>> + SoCs such as the M1. Next to the common watchdog features this >>>> + driver is also required in order to reboot these SoCs. >>>> + >>>> + To compile this driver as a module, choose M here: the >>>> + module will be called apple_wdt. >>>> + >>>> # X86 (i386 + ia64 + x86_64) Architecture >>>> >>>> config ACQUIRE_WDT >>>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile >>>> index 2ee97064145b..270a518bd8f3 100644 >>>> --- a/drivers/watchdog/Makefile >>>> +++ b/drivers/watchdog/Makefile >>>> @@ -93,6 +93,7 @@ obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o >>>> obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o >>>> obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o >>>> obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o >>>> +obj-$(CONFIG_APPLE_WATCHDOG) += apple_wdt.o >>>> >>>> # X86 (i386 + ia64 + x86_64) Architecture >>>> obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o >>>> diff --git a/drivers/watchdog/apple_wdt.c b/drivers/watchdog/apple_wdt.c >>>> new file mode 100644 >>>> index 000000000000..76e5bedd50d1 >>>> --- /dev/null >>>> +++ b/drivers/watchdog/apple_wdt.c >>>> @@ -0,0 +1,226 @@ >>>> +// SPDX-License-Identifier: GPL-2.0-only OR MIT >>>> +/* >>>> + * Apple SoC Watchdog driver >>>> + * >>>> + * Copyright (C) The Asahi Linux Contributors >>>> + */ >>>> + >>>> +#include <linux/bits.h> >>>> +#include <linux/clk.h> >>>> +#include <linux/delay.h> >>>> +#include <linux/io.h> >>>> +#include <linux/kernel.h> >>>> +#include <linux/limits.h> >>>> +#include <linux/module.h> >>>> +#include <linux/of.h> >>>> +#include <linux/platform_device.h> >>>> +#include <linux/watchdog.h> >>>> + >>>> +/* >>>> + * Apple Watchdog MMIO registers >>>> + * >>>> + * This HW block has three separate watchdogs. WD0 resets the machine >>>> + * to recovery mode and is not very useful for us. WD1 and WD2 trigger a normal >>>> + * machine reset. WD0 additionally supports a configurable interrupt. >>>> + * This information can be used to implement pretimeout support at a later time. >>>> + * >>>> + * APPLE_WDT_WDx_CUR_TIME is a simple counter incremented for each tick of the >>>> + * reference clock. It can also be overwritten to any value. >>>> + * Whenever APPLE_WDT_CTRL_RESET_EN is set in APPLE_WDT_WDx_CTRL and >>>> + * APPLE_WDTx_WD1_CUR_TIME >= APPLE_WDTx_WD1_BITE_TIME the entire machine is >>>> + * reset. >>>> + * Whenever APPLE_WDT_CTRL_IRQ_EN is set and APPLE_WDTx_WD1_CUR_TIME >= >>>> + * APPLE_WDTx_WD1_BARK_TIME an interrupt is triggered and >>>> + * APPLE_WDT_CTRL_IRQ_STATUS is set. The interrupt can be cleared by writing >>>> + * 1 to APPLE_WDT_CTRL_IRQ_STATUS. >>>> + */ >>>> +#define APPLE_WDT_WD0_CUR_TIME 0x00 >>>> +#define APPLE_WDT_WD0_BITE_TIME 0x04 >>>> +#define APPLE_WDT_WD0_BARK_TIME 0x08 >>>> +#define APPLE_WDT_WD0_CTRL 0x0c >>>> + >>>> +#define APPLE_WDT_WD1_CUR_TIME 0x10 >>>> +#define APPLE_WDT_WD1_BITE_TIME 0x14 >>>> +#define APPLE_WDT_WD1_CTRL 0x1c >>>> + >>>> +#define APPLE_WDT_WD2_CUR_TIME 0x20 >>>> +#define APPLE_WDT_WD2_BITE_TIME 0x24 >>>> +#define APPLE_WDT_WD2_CTRL 0x2c >>>> + >>>> +#define APPLE_WDT_CTRL_IRQ_EN BIT(0) >>>> +#define APPLE_WDT_CTRL_IRQ_STATUS BIT(1) >>>> +#define APPLE_WDT_CTRL_RESET_EN BIT(2) >>>> + >>>> +#define APPLE_WDT_TIMEOUT_DEFAULT 30 >>>> + >>>> +struct apple_wdt { >>>> + struct watchdog_device wdd; >>>> + void __iomem *regs; >>>> + unsigned long clk_rate; >>>> +}; >>>> + >>>> +static struct apple_wdt *to_apple_wdt(struct watchdog_device *wdd) >>>> +{ >>>> + return container_of(wdd, struct apple_wdt, wdd); >>>> +} >>>> + >>>> +static int apple_wdt_start(struct watchdog_device *wdd) >>>> +{ >>>> + struct apple_wdt *wdt = to_apple_wdt(wdd); >>>> + >>>> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >>>> + writel_relaxed(APPLE_WDT_CTRL_RESET_EN, wdt->regs + APPLE_WDT_WD1_CTRL); >>>> + >>>> + return 0; >>>> +} >>>> + >>>> +static int apple_wdt_stop(struct watchdog_device *wdd) >>>> +{ >>>> + struct apple_wdt *wdt = to_apple_wdt(wdd); >>>> + >>>> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CTRL); >>>> + >>>> + return 0; >>>> +} >>>> + >>>> +static int apple_wdt_ping(struct watchdog_device *wdd) >>>> +{ >>>> + struct apple_wdt *wdt = to_apple_wdt(wdd); >>>> + >>>> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >>>> + >>>> + return 0; >>>> +} >>>> + >>>> +static int apple_wdt_set_timeout(struct watchdog_device *wdd, unsigned int s) >>>> +{ >>>> + struct apple_wdt *wdt = to_apple_wdt(wdd); >>>> + >>>> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >>>> + writel_relaxed(wdt->clk_rate * s, wdt->regs + APPLE_WDT_WD1_BITE_TIME); >>>> + >>>> + wdd->timeout = s; >>>> + >>>> + return 0; >>>> +} >>>> + >>>> +static unsigned int apple_wdt_get_timeleft(struct watchdog_device *wdd) >>>> +{ >>>> + struct apple_wdt *wdt = to_apple_wdt(wdd); >>>> + u32 cur_time, reset_time; >>>> + >>>> + cur_time = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CUR_TIME); >>>> + reset_time = readl_relaxed(wdt->regs + APPLE_WDT_WD1_BITE_TIME); >>>> + >>>> + return (reset_time - cur_time) / wdt->clk_rate; >>>> +} >>>> + >>>> +static int apple_wdt_restart(struct watchdog_device *wdd, unsigned long mode, >>>> + void *cmd) >>>> +{ >>>> + struct apple_wdt *wdt = to_apple_wdt(wdd); >>>> + >>>> + writel_relaxed(APPLE_WDT_CTRL_RESET_EN, wdt->regs + APPLE_WDT_WD1_CTRL); >>>> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_BITE_TIME); >>>> + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); >>>> + >>>> + /* >>>> + * Flush writes and then wait for the SoC to reset. Even though the >>>> + * reset is queued almost immediately experiments have shown that it >>>> + * can take up to ~20-25ms until the SoC is actually reset. Just wait >>>> + * 50ms here to be safe. >>>> + */ >>>> + (void)readl_relaxed(wdt->regs + APPLE_WDT_WD1_CUR_TIME); >>>> + mdelay(50); >>>> + >>>> + return 0; >>>> +} >>>> + >>>> +static void apple_wdt_clk_disable_unprepare(void *data) >>>> +{ >>>> + clk_disable_unprepare(data); >>>> +} >>>> + >>>> +static struct watchdog_ops apple_wdt_ops = { >>>> + .owner = THIS_MODULE, >>>> + .start = apple_wdt_start, >>>> + .stop = apple_wdt_stop, >>>> + .ping = apple_wdt_ping, >>>> + .set_timeout = apple_wdt_set_timeout, >>>> + .get_timeleft = apple_wdt_get_timeleft, >>>> + .restart = apple_wdt_restart, >>>> +}; >>>> + >>>> +static struct watchdog_info apple_wdt_info = { >>>> + .identity = "Apple SoC Watchdog", >>>> + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, >>>> +}; >>>> + >>>> +static int apple_wdt_probe(struct platform_device *pdev) >>>> +{ >>>> + struct device *dev = &pdev->dev; >>>> + struct apple_wdt *wdt; >>>> + struct clk *clk; >>>> + u32 wdt_ctrl; >>>> + int ret; >>>> + >>>> + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); >>>> + if (!wdt) >>>> + return -ENOMEM; >>>> + >>>> + wdt->regs = devm_platform_ioremap_resource(pdev, 0); >>>> + if (IS_ERR(wdt->regs)) >>>> + return PTR_ERR(wdt->regs); >>>> + >>>> + clk = devm_clk_get(dev, NULL); >>>> + if (IS_ERR(clk)) >>>> + return PTR_ERR(clk); >>>> + >>>> + ret = clk_prepare_enable(clk); >>>> + if (ret) >>>> + return ret; >>>> + >>>> + ret = devm_add_action_or_reset(dev, apple_wdt_clk_disable_unprepare, >>>> + clk); >>>> + if (ret) >>>> + return ret; >>>> + >>>> + wdt->clk_rate = clk_get_rate(clk); >>>> + if (!wdt->clk_rate) >>>> + return -EINVAL; >>>> + >>>> + wdt->wdd.ops = &apple_wdt_ops; >>>> + wdt->wdd.info = &apple_wdt_info; >>>> + wdt->wdd.max_timeout = U32_MAX / wdt->clk_rate; >>>> + wdt->wdd.timeout = APPLE_WDT_TIMEOUT_DEFAULT; >>>> + >>>> + wdt_ctrl = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CTRL); >>>> + if (wdt_ctrl & APPLE_WDT_CTRL_RESET_EN) >>>> + set_bit(WDOG_HW_RUNNING, &wdt->wdd.status); >>>> + >>>> + watchdog_init_timeout(&wdt->wdd, 0, dev); >>>> + apple_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout); >>>> + watchdog_stop_on_unregister(&wdt->wdd); >>>> + watchdog_set_restart_priority(&wdt->wdd, 128); >>>> + >>>> + return devm_watchdog_register_device(dev, &wdt->wdd); >>>> +} >>>> + >>>> +static const struct of_device_id apple_wdt_of_match[] = { >>>> + { .compatible = "apple,wdt" }, >>>> + {}, >>>> +}; >>>> +MODULE_DEVICE_TABLE(of, apple_wdt_of_match); >>>> + >>>> +static struct platform_driver apple_wdt_driver = { >>>> + .driver = { >>>> + .name = "apple-watchdog", >>>> + .of_match_table = apple_wdt_of_match, >>>> + }, >>>> + .probe = apple_wdt_probe, >>>> +}; >>>> +module_platform_driver(apple_wdt_driver); >>>> + >>>> +MODULE_DESCRIPTION("Apple SoC watchdog driver"); >>>> +MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>"); >>>> +MODULE_LICENSE("Dual MIT/GPL"); >>> >>> Reviewed-by: Hector Martin <marcan@marcan.st> >>> >>> Thanks, looks good! Any chance you can do a quick v3 with the MAINTAINERS changes split off? As usual, I'd rather make life easier for people merging upstream :) >>> >> >> Usually I don't ask for such a split, and I don't recall that being an issue. >> So, from my perspective, that is not necessary. > > We're upstreaming a bunch of things in parallel that touch the same MAINTAINERS section, and if each of those goes through subsystem trees, they all end up creating a pile of conflicts when merged. This has already happened a few times (I got a ping from linux-next about it the other day). > > To make life easier for upstream mergers, we prefer to split off MAINTAINERS changes. Then instead of going through the subsystem tree, I can push those up through the SoC tree, making sure to resolve any conflicts/ordering issues. Then everyone upstream of us is happy :-) > Ok, makes sense. Thanks, Guenter
diff --git a/MAINTAINERS b/MAINTAINERS index 859201bbd4e8..6190f0b40983 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -1757,6 +1757,7 @@ F: drivers/i2c/busses/i2c-pasemi-platform.c F: drivers/irqchip/irq-apple-aic.c F: drivers/mailbox/apple-mailbox.c F: drivers/pinctrl/pinctrl-apple-gpio.c +F: drivers/watchdog/apple_wdt.c F: include/dt-bindings/interrupt-controller/apple-aic.h F: include/dt-bindings/pinctrl/apple.h F: include/linux/apple-mailbox.h diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index 9d222ba17ec6..170dec880c8f 100644 --- a/drivers/watchdog/Kconfig +++ b/drivers/watchdog/Kconfig @@ -976,6 +976,18 @@ config MSC313E_WATCHDOG To compile this driver as a module, choose M here: the module will be called msc313e_wdt. +config APPLE_WATCHDOG + tristate "Apple SoC watchdog" + depends on ARCH_APPLE || COMPILE_TEST + select WATCHDOG_CORE + help + Say Y here to include support for the Watchdog found in Apple + SoCs such as the M1. Next to the common watchdog features this + driver is also required in order to reboot these SoCs. + + To compile this driver as a module, choose M here: the + module will be called apple_wdt. + # X86 (i386 + ia64 + x86_64) Architecture config ACQUIRE_WDT diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile index 2ee97064145b..270a518bd8f3 100644 --- a/drivers/watchdog/Makefile +++ b/drivers/watchdog/Makefile @@ -93,6 +93,7 @@ obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o +obj-$(CONFIG_APPLE_WATCHDOG) += apple_wdt.o # X86 (i386 + ia64 + x86_64) Architecture obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o diff --git a/drivers/watchdog/apple_wdt.c b/drivers/watchdog/apple_wdt.c new file mode 100644 index 000000000000..76e5bedd50d1 --- /dev/null +++ b/drivers/watchdog/apple_wdt.c @@ -0,0 +1,226 @@ +// SPDX-License-Identifier: GPL-2.0-only OR MIT +/* + * Apple SoC Watchdog driver + * + * Copyright (C) The Asahi Linux Contributors + */ + +#include <linux/bits.h> +#include <linux/clk.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/limits.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/watchdog.h> + +/* + * Apple Watchdog MMIO registers + * + * This HW block has three separate watchdogs. WD0 resets the machine + * to recovery mode and is not very useful for us. WD1 and WD2 trigger a normal + * machine reset. WD0 additionally supports a configurable interrupt. + * This information can be used to implement pretimeout support at a later time. + * + * APPLE_WDT_WDx_CUR_TIME is a simple counter incremented for each tick of the + * reference clock. It can also be overwritten to any value. + * Whenever APPLE_WDT_CTRL_RESET_EN is set in APPLE_WDT_WDx_CTRL and + * APPLE_WDTx_WD1_CUR_TIME >= APPLE_WDTx_WD1_BITE_TIME the entire machine is + * reset. + * Whenever APPLE_WDT_CTRL_IRQ_EN is set and APPLE_WDTx_WD1_CUR_TIME >= + * APPLE_WDTx_WD1_BARK_TIME an interrupt is triggered and + * APPLE_WDT_CTRL_IRQ_STATUS is set. The interrupt can be cleared by writing + * 1 to APPLE_WDT_CTRL_IRQ_STATUS. + */ +#define APPLE_WDT_WD0_CUR_TIME 0x00 +#define APPLE_WDT_WD0_BITE_TIME 0x04 +#define APPLE_WDT_WD0_BARK_TIME 0x08 +#define APPLE_WDT_WD0_CTRL 0x0c + +#define APPLE_WDT_WD1_CUR_TIME 0x10 +#define APPLE_WDT_WD1_BITE_TIME 0x14 +#define APPLE_WDT_WD1_CTRL 0x1c + +#define APPLE_WDT_WD2_CUR_TIME 0x20 +#define APPLE_WDT_WD2_BITE_TIME 0x24 +#define APPLE_WDT_WD2_CTRL 0x2c + +#define APPLE_WDT_CTRL_IRQ_EN BIT(0) +#define APPLE_WDT_CTRL_IRQ_STATUS BIT(1) +#define APPLE_WDT_CTRL_RESET_EN BIT(2) + +#define APPLE_WDT_TIMEOUT_DEFAULT 30 + +struct apple_wdt { + struct watchdog_device wdd; + void __iomem *regs; + unsigned long clk_rate; +}; + +static struct apple_wdt *to_apple_wdt(struct watchdog_device *wdd) +{ + return container_of(wdd, struct apple_wdt, wdd); +} + +static int apple_wdt_start(struct watchdog_device *wdd) +{ + struct apple_wdt *wdt = to_apple_wdt(wdd); + + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); + writel_relaxed(APPLE_WDT_CTRL_RESET_EN, wdt->regs + APPLE_WDT_WD1_CTRL); + + return 0; +} + +static int apple_wdt_stop(struct watchdog_device *wdd) +{ + struct apple_wdt *wdt = to_apple_wdt(wdd); + + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CTRL); + + return 0; +} + +static int apple_wdt_ping(struct watchdog_device *wdd) +{ + struct apple_wdt *wdt = to_apple_wdt(wdd); + + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); + + return 0; +} + +static int apple_wdt_set_timeout(struct watchdog_device *wdd, unsigned int s) +{ + struct apple_wdt *wdt = to_apple_wdt(wdd); + + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); + writel_relaxed(wdt->clk_rate * s, wdt->regs + APPLE_WDT_WD1_BITE_TIME); + + wdd->timeout = s; + + return 0; +} + +static unsigned int apple_wdt_get_timeleft(struct watchdog_device *wdd) +{ + struct apple_wdt *wdt = to_apple_wdt(wdd); + u32 cur_time, reset_time; + + cur_time = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CUR_TIME); + reset_time = readl_relaxed(wdt->regs + APPLE_WDT_WD1_BITE_TIME); + + return (reset_time - cur_time) / wdt->clk_rate; +} + +static int apple_wdt_restart(struct watchdog_device *wdd, unsigned long mode, + void *cmd) +{ + struct apple_wdt *wdt = to_apple_wdt(wdd); + + writel_relaxed(APPLE_WDT_CTRL_RESET_EN, wdt->regs + APPLE_WDT_WD1_CTRL); + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_BITE_TIME); + writel_relaxed(0, wdt->regs + APPLE_WDT_WD1_CUR_TIME); + + /* + * Flush writes and then wait for the SoC to reset. Even though the + * reset is queued almost immediately experiments have shown that it + * can take up to ~20-25ms until the SoC is actually reset. Just wait + * 50ms here to be safe. + */ + (void)readl_relaxed(wdt->regs + APPLE_WDT_WD1_CUR_TIME); + mdelay(50); + + return 0; +} + +static void apple_wdt_clk_disable_unprepare(void *data) +{ + clk_disable_unprepare(data); +} + +static struct watchdog_ops apple_wdt_ops = { + .owner = THIS_MODULE, + .start = apple_wdt_start, + .stop = apple_wdt_stop, + .ping = apple_wdt_ping, + .set_timeout = apple_wdt_set_timeout, + .get_timeleft = apple_wdt_get_timeleft, + .restart = apple_wdt_restart, +}; + +static struct watchdog_info apple_wdt_info = { + .identity = "Apple SoC Watchdog", + .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT, +}; + +static int apple_wdt_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct apple_wdt *wdt; + struct clk *clk; + u32 wdt_ctrl; + int ret; + + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL); + if (!wdt) + return -ENOMEM; + + wdt->regs = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(wdt->regs)) + return PTR_ERR(wdt->regs); + + clk = devm_clk_get(dev, NULL); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + ret = clk_prepare_enable(clk); + if (ret) + return ret; + + ret = devm_add_action_or_reset(dev, apple_wdt_clk_disable_unprepare, + clk); + if (ret) + return ret; + + wdt->clk_rate = clk_get_rate(clk); + if (!wdt->clk_rate) + return -EINVAL; + + wdt->wdd.ops = &apple_wdt_ops; + wdt->wdd.info = &apple_wdt_info; + wdt->wdd.max_timeout = U32_MAX / wdt->clk_rate; + wdt->wdd.timeout = APPLE_WDT_TIMEOUT_DEFAULT; + + wdt_ctrl = readl_relaxed(wdt->regs + APPLE_WDT_WD1_CTRL); + if (wdt_ctrl & APPLE_WDT_CTRL_RESET_EN) + set_bit(WDOG_HW_RUNNING, &wdt->wdd.status); + + watchdog_init_timeout(&wdt->wdd, 0, dev); + apple_wdt_set_timeout(&wdt->wdd, wdt->wdd.timeout); + watchdog_stop_on_unregister(&wdt->wdd); + watchdog_set_restart_priority(&wdt->wdd, 128); + + return devm_watchdog_register_device(dev, &wdt->wdd); +} + +static const struct of_device_id apple_wdt_of_match[] = { + { .compatible = "apple,wdt" }, + {}, +}; +MODULE_DEVICE_TABLE(of, apple_wdt_of_match); + +static struct platform_driver apple_wdt_driver = { + .driver = { + .name = "apple-watchdog", + .of_match_table = apple_wdt_of_match, + }, + .probe = apple_wdt_probe, +}; +module_platform_driver(apple_wdt_driver); + +MODULE_DESCRIPTION("Apple SoC watchdog driver"); +MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>"); +MODULE_LICENSE("Dual MIT/GPL");
Add support for the watchdog timer found in Apple SoCs. This driver is also required to reboot these machines. Signed-off-by: Sven Peter <sven@svenpeter.dev> --- v1 -> v2: - set the default timeout to 30s and call watchdog_init_timeout to allow the device tree to override it - set WDOG_HW_RUNNING if the watchdog is enabled at boot - check that the clock rate is not zero - use unsigned long instead of u32 for clk_rate - use devm_add_action_or_reset instead of manually calling clk_disable_unprepare - explain the magic number in apple_wdt_restart MAINTAINERS | 1 + drivers/watchdog/Kconfig | 12 ++ drivers/watchdog/Makefile | 1 + drivers/watchdog/apple_wdt.c | 226 +++++++++++++++++++++++++++++++++++ 4 files changed, 240 insertions(+) create mode 100644 drivers/watchdog/apple_wdt.c