Messages in this thread | | | Subject | Re: [PATCH v3 2/2] watchdog: Add Spreadtrum watchdog driver | From | Guenter Roeck <> | Date | Fri, 27 Oct 2017 06:42:11 -0700 |
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On 10/27/2017 12:54 AM, Eric Long wrote: > Hi Guenter, > > Thanks for you commonts. > > On Thu, Oct 26, 2017 at 10:23:40PM -0700, Guenter Roeck wrote: >> On 10/26/2017 07:28 PM, Eric Long wrote: >>> This patch adds the watchdog driver for Spreadtrum SC9860 platform. >>> >>> Signed-off-by: Eric Long <eric.long@spreadtrum.com> >>> --- >>> Change since v2: >>> - Rename all the macors, add SPRD tag at the head of the macro names. >>> - Rename SPRD_WDT_CLK as SPRD_WTC_CNT_STEP. >>> - Remove the code which check timeout value at the wrong place. >>> - Add min/max timeout value limit. >>> - Remove set WDOG_HW_RUNNING status at sprd_wdt_enable(). >>> - Add timeout/pretimeout judgment when set them. >>> - Support WATCHDOG_NOWAYOUT status. >>> >>> Changes since v1: >>> - Use pretimeout instead of own implementation. >>> - Fix timeout loop when loading timeout values. >>> - use the infrastructure to read and set "timeout-sec" property. >>> - Add conditions when start or stop watchdog. >>> - Change the position of enabling watchdog. >>> - Other optimization. >>> --- >>> drivers/watchdog/Kconfig | 8 + >>> drivers/watchdog/Makefile | 1 + >>> drivers/watchdog/sprd_wdt.c | 415 ++++++++++++++++++++++++++++++++++++++++++++ >>> 3 files changed, 424 insertions(+) >>> create mode 100644 drivers/watchdog/sprd_wdt.c >>> >>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig >>> index c722cbf..4a77e17 100644 >>> --- a/drivers/watchdog/Kconfig >>> +++ b/drivers/watchdog/Kconfig >>> @@ -787,6 +787,14 @@ config UNIPHIER_WATCHDOG >>> To compile this driver as a module, choose M here: the >>> module will be called uniphier_wdt. >>> +config SPRD_WATCHDOG >>> + tristate "Spreadtrum watchdog support" >>> + depends on ARCH_SPRD || COMPILE_TEST >>> + select WATCHDOG_CORE >>> + help >>> + Say Y here to include support watchdog timer embedded >>> + into the Spreadtrum system. >> >> Maybe better "supported by" instead of "embedded into". Or at least >> "embedded in". > > OK, I will fix it. > >>> + >>> # AVR32 Architecture >>> config AT32AP700X_WDT >>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile >>> index 56adf9f..187cca2 100644 >>> --- a/drivers/watchdog/Makefile >>> +++ b/drivers/watchdog/Makefile >>> @@ -87,6 +87,7 @@ obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o >>> obj-$(CONFIG_ZX2967_WATCHDOG) += zx2967_wdt.o >>> obj-$(CONFIG_STM32_WATCHDOG) += stm32_iwdg.o >>> obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o >>> +obj-$(CONFIG_SPRD_WATCHDOG) += sprd_wdt.o >>> # AVR32 Architecture >>> obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o >>> diff --git a/drivers/watchdog/sprd_wdt.c b/drivers/watchdog/sprd_wdt.c >>> new file mode 100644 >>> index 0000000..5fc3dde >>> --- /dev/null >>> +++ b/drivers/watchdog/sprd_wdt.c >>> @@ -0,0 +1,415 @@ >>> +/* >>> + * Spreadtrum watchdog driver >>> + * Copyright (C) 2017 Spreadtrum - http://www.spreadtrum.com >>> + * >>> + * This program is free software; you can redistribute it and/or >>> + * modify it under the terms of the GNU General Public License >>> + * version 2 as published by the Free Software Foundation. >>> + * >>> + * This program is distributed in the hope that it will be useful, but >>> + * WITHOUT ANY WARRANTY; without even the implied warranty of >>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU >>> + * General Public License for more details. >>> + */ >>> + >>> +#include <linux/bitops.h> >>> +#include <linux/clk.h> >>> +#include <linux/err.h> >>> +#include <linux/interrupt.h> >>> +#include <linux/io.h> >>> +#include <linux/kernel.h> >>> +#include <linux/module.h> >>> +#include <linux/of.h> >>> +#include <linux/of_address.h> >>> +#include <linux/platform_device.h> >>> +#include <linux/watchdog.h> >>> + >>> +#define SPRD_WDT_LOAD_LOW 0x0 >>> +#define SPRD_WDT_LOAD_HIGH 0x4 >>> +#define SPRD_WDT_CTRL 0x8 >>> +#define SPRD_WDT_INT_CLR 0xc >>> +#define SPRD_WDT_INT_RAW 0x10 >>> +#define SPRD_WDT_INT_MSK 0x14 >>> +#define SPRD_WDT_CNT_LOW 0x18 >>> +#define SPRD_WDT_CNT_HIGH 0x1c >>> +#define SPRD_WDT_LOCK 0x20 >>> +#define SPRD_WDT_IRQ_LOAD_LOW 0x2c >>> +#define SPRD_WDT_IRQ_LOAD_HIGH 0x30 >>> + >>> +/* WDT_CTRL */ >>> +#define SPRD_WDT_INT_EN_BIT BIT(0) >>> +#define SPRD_WDT_CNT_EN_BIT BIT(1) >>> +#define SPRD_WDT_NEW_VER_EN BIT(2) >>> +#define SPRD_WDT_RST_EN_BIT BIT(3) >>> + >>> +/* WDT_INT_CLR */ >>> +#define SPRD_WDT_INT_CLEAR_BIT BIT(0) >>> +#define SPRD_WDT_RST_CLEAR_BIT BIT(3) >>> + >>> +/* WDT_INT_RAW */ >>> +#define SPRD_WDT_INT_RAW_BIT BIT(0) >>> +#define SPRD_WDT_RST_RAW_BIT BIT(3) >>> +#define SPRD_WDT_LD_BUSY_BIT BIT(4) >>> + >>> +/* 1s equale to 32768 counter steps */ >> >> equal ? >> > > OK, I will fix it. > >>> +#define SPRD_WDT_CNT_STEP 32768 >>> + >>> +#define SPRD_WDT_UNLOCK_KEY 0xe551 >>> +#define SPRD_WDT_MIN_TIMROUT 3 >> >> TIMROUT ot TIMEOUT ? >> > > OK, I will fix it. > >>> +#define SPRD_WDT_MAX_TIMEOUT 60 >> >> Is that really the maximum supported timeout ? Seems a bit low. >> Shouldn't it be something like (U32_MAX / SPRD_WDT_CNT_STEP) ? >> > > It supports the max value like as U32_MAX/SPRD_WDT_CNT_STEP, > but it doesn't unnecessary to support so big value, if the system can not > response it in 60s, the watchdog could trigger timeout. > It is customary to provide the highest possible value here. No one is forced to set such high values. You are making a choice for others here. But, sure, if you insist; not worth arguing about.
>>> + >>> +#define SPRD_WDT_CNT_HIGH_VALUE 16 >> >> Maybe name it "SPRD_WDT_CNT_HIGH_SHIFT". It is not really a value, >> it is a shift. >> > > Yes, you are right, _SHIFT will be better. > >>> +#define SPRD_WDT_LOW_VALUE_MASK GENMASK(15, 0) >>> +#define SPRD_WDT_CNT_VALUE_MAX GENMASK(31, 0) >> >> Does this mask serve a useful purpose ? >> > > OK, I will remove it, thanks! > >>> +#define SPRD_WDT_LOAD_TIMEOUT 1000 >>> + >>> +struct sprd_wdt { >>> + void __iomem *base; >>> + struct watchdog_device wdd; >>> + struct clk *enable; >>> + struct clk *rtc_enable; >>> + unsigned int irq; >>> +}; >>> + >>> +static inline struct sprd_wdt *to_sprd_wdt(struct watchdog_device *wdd) >>> +{ >>> + return container_of(wdd, struct sprd_wdt, wdd); >>> +} >>> + >>> +static inline void sprd_wdt_lock(void __iomem *addr) >>> +{ >>> + writel_relaxed(0x0, addr + SPRD_WDT_LOCK); >>> +} >>> + >>> +static inline void sprd_wdt_unlock(void __iomem *addr) >>> +{ >>> + writel_relaxed(SPRD_WDT_UNLOCK_KEY, addr + SPRD_WDT_LOCK); >>> +} >>> + >>> +static inline bool sprd_wdt_is_running(struct sprd_wdt *wdt) >>> +{ >>> + u32 val; >>> + >>> + val = readl_relaxed(wdt->base + SPRD_WDT_CTRL); >>> + return val & SPRD_WDT_NEW_VER_EN; >>> +} >>> + >>> +static irqreturn_t sprd_wdt_isr(int irq, void *dev_id) >>> +{ >>> + struct sprd_wdt *wdt = (struct sprd_wdt *)dev_id; >>> + >>> + sprd_wdt_unlock(wdt->base); >>> + writel_relaxed(SPRD_WDT_INT_CLEAR_BIT, wdt->base + SPRD_WDT_INT_CLR); >>> + sprd_wdt_lock(wdt->base); >>> + watchdog_notify_pretimeout(&wdt->wdd); >>> + return IRQ_HANDLED; >>> +} >>> + >>> +static u32 sprd_wdt_get_cnt_value(struct sprd_wdt *wdt) >>> +{ >>> + u32 val; >>> + >>> + val = readl_relaxed(wdt->base + SPRD_WDT_CNT_HIGH) << >>> + SPRD_WDT_CNT_HIGH_VALUE; >>> + val |= readl_relaxed(wdt->base + SPRD_WDT_CNT_LOW) & >>> + SPRD_WDT_LOW_VALUE_MASK; >>> + >>> + return val; >>> +} >>> + >>> +static int sprd_wdt_load_value(struct sprd_wdt *wdt, u32 timeout, >>> + u32 pretimeout) >>> +{ >>> + u32 val, delay_cnt = 0; >>> + u32 tmr_step = timeout * SPRD_WDT_CNT_STEP; >>> + u32 prtmr_step = pretimeout * SPRD_WDT_CNT_STEP; >>> + >>> + sprd_wdt_unlock(wdt->base); >>> + writel_relaxed((tmr_step >> SPRD_WDT_CNT_HIGH_VALUE) & >>> + SPRD_WDT_LOW_VALUE_MASK, wdt->base + SPRD_WDT_LOAD_HIGH); >>> + writel_relaxed((tmr_step & SPRD_WDT_LOW_VALUE_MASK), >>> + wdt->base + SPRD_WDT_LOAD_LOW); >>> + writel_relaxed((prtmr_step >> SPRD_WDT_CNT_HIGH_VALUE) & >>> + SPRD_WDT_LOW_VALUE_MASK, >>> + wdt->base + SPRD_WDT_IRQ_LOAD_HIGH); >>> + writel_relaxed(prtmr_step & SPRD_WDT_LOW_VALUE_MASK, >>> + wdt->base + SPRD_WDT_IRQ_LOAD_LOW); >>> + sprd_wdt_lock(wdt->base); >>> + >>> + /* >>> + * Waiting the load value operation done, >>> + * it needs two or three RTC clock cycles. >>> + */ >>> + do { >>> + val = readl_relaxed(wdt->base + SPRD_WDT_INT_RAW); >>> + if (!(val & SPRD_WDT_LD_BUSY_BIT)) >>> + break; >>> + >>> + cpu_relax(); >>> + } while (delay_cnt++ < SPRD_WDT_LOAD_TIMEOUT); >>> + >>> + if (delay_cnt >= SPRD_WDT_LOAD_TIMEOUT) >>> + return -EBUSY; >>> + return 0; >>> +} >>> + >>> +static int sprd_wdt_enable(struct sprd_wdt *wdt) >>> +{ >>> + u32 val; >>> + int ret; >>> + >>> + ret = clk_prepare_enable(wdt->enable); >>> + if (ret) >>> + return ret; >>> + ret = clk_prepare_enable(wdt->rtc_enable); >>> + if (ret) >>> + return ret; >>> + >>> + sprd_wdt_unlock(wdt->base); >>> + val = readl_relaxed(wdt->base + SPRD_WDT_CTRL); >>> + val |= SPRD_WDT_NEW_VER_EN; >>> + writel_relaxed(val, wdt->base + SPRD_WDT_CTRL); >>> + sprd_wdt_lock(wdt->base); >>> + return 0; >>> +} >>> + >>> +static void sprd_wdt_disable(struct sprd_wdt *wdt) >>> +{ >>> + sprd_wdt_unlock(wdt->base); >>> + writel_relaxed(0x0, wdt->base + SPRD_WDT_CTRL); >>> + sprd_wdt_lock(wdt->base); >>> + >>> + clk_disable_unprepare(wdt->rtc_enable); >>> + clk_disable_unprepare(wdt->enable); >>> +} >>> + >>> +static int sprd_wdt_start(struct watchdog_device *wdd) >>> +{ >>> + struct sprd_wdt *wdt = to_sprd_wdt(wdd); >>> + u32 val; >>> + int ret; >>> + >>> + ret = sprd_wdt_load_value(wdt, wdd->timeout, wdd->pretimeout); >>> + if (ret) >>> + return ret; >>> + >>> + sprd_wdt_unlock(wdt->base); >>> + val = readl_relaxed(wdt->base + SPRD_WDT_CTRL); >>> + val |= SPRD_WDT_CNT_EN_BIT | SPRD_WDT_INT_EN_BIT | SPRD_WDT_RST_EN_BIT; >>> + writel_relaxed(val, wdt->base + SPRD_WDT_CTRL); >>> + sprd_wdt_lock(wdt->base); >>> + set_bit(WDOG_HW_RUNNING, &wdd->status); >>> + >>> + return 0; >>> +} >>> + >>> +static int sprd_wdt_stop(struct watchdog_device *wdd) >>> +{ >>> + struct sprd_wdt *wdt = to_sprd_wdt(wdd); >>> + u32 val; >>> + >>> + sprd_wdt_unlock(wdt->base); >>> + val = readl_relaxed(wdt->base + SPRD_WDT_CTRL); >>> + val &= ~(SPRD_WDT_CNT_EN_BIT | SPRD_WDT_RST_EN_BIT | >>> + SPRD_WDT_INT_EN_BIT); >>> + writel_relaxed(val, wdt->base + SPRD_WDT_CTRL); >>> + sprd_wdt_lock(wdt->base); >>> + return 0; >>> +} >>> + >>> +static int sprd_wdt_set_timeout(struct watchdog_device *wdd, >>> + u32 timeout) >>> +{ >>> + struct sprd_wdt *wdt = to_sprd_wdt(wdd); >>> + >>> + if (timeout == wdd->timeout) >>> + return 0; >>> + >>> + wdd->timeout = timeout; >>> + >>> + return sprd_wdt_load_value(wdt, timeout, wdd->pretimeout); >>> +} >>> + >>> +static int sprd_wdt_set_pretimeout(struct watchdog_device *wdd, >>> + u32 new_pretimeout) >>> +{ >>> + struct sprd_wdt *wdt = to_sprd_wdt(wdd); >>> + >>> + if (new_pretimeout == wdd->pretimeout) >>> + return 0; >> >> This is inconsistent. pretimeout == 0 is accepted until it is set >> to a non-zero value once, then 0 is no longer accepted. pretimeout==0 >> should reflect "pretimeout disabled". If that is not possible you >> need to set some non-0 default value in the probe function. >> > > I understand your opinion, I will fix it. > >>> + if (new_pretimeout <= wdd->min_timeout) >>> + return -EINVAL; >> >> Why is pretimeout == wdd->min_timeout invalid ? >> > > OK, you are right, it should be pretimeout < min_timeout. > >>> + >>> + wdd->pretimeout = new_pretimeout; >>> + >>> + return sprd_wdt_load_value(wdt, wdd->timeout, new_pretimeout); >>> +} >>> + >>> +static u32 sprd_wdt_get_timeleft(struct watchdog_device *wdd) >>> +{ >>> + struct sprd_wdt *wdt = to_sprd_wdt(wdd); >>> + u32 val; >>> + >>> + val = sprd_wdt_get_cnt_value(wdt); >>> + val = val / SPRD_WDT_CNT_STEP; >>> + >>> + return val; >>> +} >>> + >>> +static const struct watchdog_ops sprd_wdt_ops = { >>> + .owner = THIS_MODULE, >>> + .start = sprd_wdt_start, >>> + .stop = sprd_wdt_stop, >>> + .set_timeout = sprd_wdt_set_timeout, >>> + .set_pretimeout = sprd_wdt_set_pretimeout, >>> + .get_timeleft = sprd_wdt_get_timeleft, >> >> Just wondering - no heartbeat function ? Having to load the timer >> values for each heartbeat is expensive. >> > > Unfortunately, this watchdog has not RELOAD register. > >>> +}; >>> + >>> +static const struct watchdog_info sprd_wdt_info = { >>> + .options = WDIOF_SETTIMEOUT | >>> + WDIOF_PRETIMEOUT | >>> + WDIOF_MAGICCLOSE | >>> + WDIOF_KEEPALIVEPING, >>> + .identity = "Spreadtrum Watchdog Timer", >>> +}; >>> + >>> +static int sprd_wdt_probe(struct platform_device *pdev) >>> +{ >>> + struct resource *wdt_res; >>> + struct sprd_wdt *wdt; >>> + int ret; >>> + >>> + wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL); >>> + if (!wdt) >>> + return -ENOMEM; >>> + >>> + wdt_res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >>> + if (!wdt_res) { >>> + dev_err(&pdev->dev, "failed to memory resource\n"); >>> + return -ENOMEM; >>> + } >> >> Unnecessary error check and message. devm_ioremap_resource() >> returns an error if res is NULL. >> > > OK, I will fix it. > >>> + >>> + wdt->base = devm_ioremap_resource(&pdev->dev, wdt_res); >>> + if (IS_ERR(wdt->base)) >> >> Move the error message to here. >> >>> + return PTR_ERR(wdt->base); >>> + >>> + wdt->enable = devm_clk_get(&pdev->dev, "enable"); >>> + if (IS_ERR(wdt->enable)) { >>> + dev_err(&pdev->dev, "can't get the enable clock\n"); >>> + return PTR_ERR(wdt->enable); >>> + } >>> + >>> + wdt->rtc_enable = devm_clk_get(&pdev->dev, "rtc_enable"); >>> + if (IS_ERR(wdt->rtc_enable)) { >>> + dev_err(&pdev->dev, "can't get the rtc enable clock\n"); >>> + return PTR_ERR(wdt->rtc_enable); >>> + } >>> + >>> + wdt->irq = platform_get_irq(pdev, 0); >>> + if (wdt->irq < 0) { >>> + dev_err(&pdev->dev, "failed to get IRQ resource\n"); >>> + return wdt->irq; >>> + } >>> + >>> + ret = devm_request_irq(&pdev->dev, wdt->irq, sprd_wdt_isr, >>> + IRQF_NO_SUSPEND, "sprd-wdt", (void *)wdt); >>> + if (ret) { >>> + dev_err(&pdev->dev, "failed to register irq\n"); >>> + return ret; >>> + } >>> + >>> + wdt->wdd.info = &sprd_wdt_info; >>> + wdt->wdd.ops = &sprd_wdt_ops; >>> + wdt->wdd.parent = &pdev->dev; >>> + wdt->wdd.min_timeout = SPRD_WDT_MIN_TIMROUT; >>> + wdt->wdd.max_timeout = SPRD_WDT_MAX_TIMEOUT; >>> + >> You might want to set wdt->wdd.timeout to a default value. >> > > OK, I will set a default timeout value in case of no timeout-sec in device-tree. > >>> + ret = sprd_wdt_enable(wdt); >>> + if (ret) { >>> + dev_err(&pdev->dev, "failed to enable wdt\n"); >>> + return ret; >>> + } >>> + >> >> This needs a matching sprd_wdt_disable() call in the remove function. >> Best way to handle this would be to add devm_add_action() here. >> > > If add devm_add_action(), it will be called in the remove function, > but this is not our expect, if someone remove this module, we want it just timeout. >
But that leaves the watchdog enabled even if it was stopped (no call to sprd_wdt_disable()).
Relying on NOWAYOUT would be a better option here. Again, you are making a choice for the user.
>>> + watchdog_set_nowayout(&wdt->wdd, WATCHDOG_NOWAYOUT); >>> + watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev); >>> + >>> + ret = watchdog_register_device(&wdt->wdd); >> >> Unfortunately this doesn't work. It leaves interrupts enabled >> after the watchdog device is removed in sprd_wdt_remove(), >> but the driver will be gone. I would suggest to use >> devm_watchdog_register_device() and reorder calls to request >> the interrupt after registering the watchdog device. Then you >> can drop the remove function entirely. >> > > Yes, you are right, I understand your opinion, and it is very important, > devm_watchdog_register_device() is better. Thanks. > >>> + if (ret) { >>> + sprd_wdt_disable(wdt); >>> + dev_err(&pdev->dev, "failed to register watchdog\n"); >>> + return ret; >>> + } >>> + platform_set_drvdata(pdev, wdt); >>> + >>> + return 0; >>> +} >>> + >>> +static int sprd_wdt_remove(struct platform_device *pdev) >>> +{ >>> + struct sprd_wdt *wdt = platform_get_drvdata(pdev); >>> + >>> + watchdog_unregister_device(&wdt->wdd); >>> + >>> + if (sprd_wdt_is_running(wdt)) >>> + dev_crit(&pdev->dev, "Device removed: Expect reboot!\n"); >>> + return 0; >>> +} >>> + >>> +static int __maybe_unused sprd_wdt_pm_suspend(struct device *dev) >>> +{ >>> + struct watchdog_device *wdd = dev_get_drvdata(dev); >>> + struct sprd_wdt *wdt = dev_get_drvdata(dev); >>> + >>> + if (watchdog_active(wdd)) { >>> + sprd_wdt_stop(&wdt->wdd); >>> + sprd_wdt_disable(wdt); >> >> Are you sure you only want to disable the clocks if the watchdog was active ? >> That seems to be a bit inconsistent. >> > > This watchdog is in always on power domain, if system suspend, it needs to > disable it, or it will timeout. > That is not what I asked. I asked why it isn't
if (watchdog_active(wdd)) sprd_wdt_stop(&wdt->wdd);
sprd_wdt_disable(wdt);
instead.
>>> + } >>> + >>> + return 0; >>> +} >>> + >>> +static int __maybe_unused sprd_wdt_pm_resume(struct device *dev) >>> +{ >>> + struct watchdog_device *wdd = dev_get_drvdata(dev); >>> + struct sprd_wdt *wdt = dev_get_drvdata(dev); >>> + int ret; >>> + >>> + if (watchdog_active(wdd)) { >>> + ret = sprd_wdt_enable(wdt); >>> + if (ret) >>> + return ret; >>> + ret = sprd_wdt_start(&wdt->wdd); >>> + if (ret) { >>> + sprd_wdt_disable(wdt); >>> + return ret; >>> + } >> >> This can leave the system in an inconsistent state. Sometimes the wdt may be >> disabled, sometimes not. >> > > If watchdog enable failed, it means there is something wrong in this system. >
True.
Guenter
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