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.l...@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. > >+ > >+#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. > >+ 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. > >+ } > >+ > >+ 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. > >+ } > >+ > >+ return 0; > >+} > >+ > >+static const struct dev_pm_ops sprd_wdt_pm_ops = { > >+ SET_SYSTEM_SLEEP_PM_OPS(sprd_wdt_pm_suspend, > >+ sprd_wdt_pm_resume) > >+}; > >+ > >+static const struct of_device_id sprd_wdt_match_table[] = { > >+ { .compatible = "sprd,sp9860-wdt", }, > >+ {}, > >+}; > >+MODULE_DEVICE_TABLE(of, sprd_wdt_match_table); > >+ > >+static struct platform_driver sprd_watchdog_driver = { > >+ .probe = sprd_wdt_probe, > >+ .remove = sprd_wdt_remove, > >+ .driver = { > >+ .name = "sprd-wdt", > >+ .of_match_table = sprd_wdt_match_table, > >+ .pm = &sprd_wdt_pm_ops, > >+ }, > >+}; > >+module_platform_driver(sprd_watchdog_driver); > >+ > >+MODULE_AUTHOR("Eric Long <eric.l...@spreadtrum.com>"); > >+MODULE_DESCRIPTION("Spreadtrum Watchdog Timer Controller Driver"); > >+MODULE_LICENSE("GPL v2"); > > >
