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Message-ID: <8ba002ea-299c-2eaf-b1a7-d7d38a540152@starfivetech.com>
Date: Fri, 24 Feb 2023 15:42:51 +0800
From: Xingyu Wu <xingyu.wu@...rfivetech.com>
To: Guenter Roeck <linux@...ck-us.net>
CC: <linux-riscv@...ts.infradead.org>, <devicetree@...r.kernel.org>,
<linux-watchdog@...r.kernel.org>,
Wim Van Sebroeck <wim@...ux-watchdog.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Paul Walmsley <paul.walmsley@...ive.com>,
"Palmer Dabbelt" <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
"Philipp Zabel" <p.zabel@...gutronix.de>,
Samin Guo <samin.guo@...rfivetech.com>,
<linux-kernel@...r.kernel.org>, Conor Dooley <conor@...nel.org>
Subject: Re: [PATCH v3 2/2] drivers: watchdog: Add StarFive Watchdog driver
On 2023/2/24 2:23, Guenter Roeck wrote:
> On Mon, Feb 20, 2023 at 04:19:26PM +0800, Xingyu Wu wrote:
>> Add watchdog driver for the StarFive JH7110 SoC.
>>
>> Signed-off-by: Xingyu Wu <xingyu.wu@...rfivetech.com>
>> ---
>> MAINTAINERS | 7 +
>> drivers/watchdog/Kconfig | 9 +
>> drivers/watchdog/Makefile | 2 +
>> drivers/watchdog/starfive-wdt.c | 651 ++++++++++++++++++++++++++++++++
>> 4 files changed, 669 insertions(+)
>> create mode 100644 drivers/watchdog/starfive-wdt.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 135d93368d36..6cbcf08fa76a 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -19933,6 +19933,13 @@ F: Documentation/devicetree/bindings/reset/starfive,jh7100-reset.yaml
>> F: drivers/reset/reset-starfive-jh7100.c
>> F: include/dt-bindings/reset/starfive-jh7100.h
>>
>> +STARFIVE JH7110 WATCHDOG DRIVER
>> +M: Xingyu Wu <xingyu.wu@...rfivetech.com>
>> +M: Samin Guo <samin.guo@...rfivetech.com>
>> +S: Supported
>> +F: Documentation/devicetree/bindings/watchdog/starfive*
>> +F: drivers/watchdog/starfive-wdt.c
>> +
>> STATIC BRANCH/CALL
>> M: Peter Zijlstra <peterz@...radead.org>
>> M: Josh Poimboeuf <jpoimboe@...nel.org>
>> diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
>> index 0bc40b763b06..4608eb5c9501 100644
>> --- a/drivers/watchdog/Kconfig
>> +++ b/drivers/watchdog/Kconfig
>> @@ -2089,6 +2089,15 @@ config UML_WATCHDOG
>> tristate "UML watchdog"
>> depends on UML || COMPILE_TEST
>>
>> +config STARFIVE_WATCHDOG
>> + tristate "StarFive Watchdog support"
>> + depends on RISCV
>> + select WATCHDOG_CORE
>> + default SOC_STARFIVE
>> + help
>> + Say Y here to support the watchdog of StarFive JH7110 SoC.
>> + This driver can also be built as a module if choose M.
>> +
>> #
>> # ISA-based Watchdog Cards
>> #
>> diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
>> index 9cbf6580f16c..4c0bd377e92a 100644
>> --- a/drivers/watchdog/Makefile
>> +++ b/drivers/watchdog/Makefile
>> @@ -211,6 +211,8 @@ obj-$(CONFIG_WATCHDOG_SUN4V) += sun4v_wdt.o
>> # Xen
>> obj-$(CONFIG_XEN_WDT) += xen_wdt.o
>>
>> +obj-$(CONFIG_STARFIVE_WATCHDOG) += starfive-wdt.o
>> +
>> # Architecture Independent
>> obj-$(CONFIG_BD957XMUF_WATCHDOG) += bd9576_wdt.o
>> obj-$(CONFIG_DA9052_WATCHDOG) += da9052_wdt.o
>> diff --git a/drivers/watchdog/starfive-wdt.c b/drivers/watchdog/starfive-wdt.c
>> new file mode 100644
>> index 000000000000..dfbb80406076
>> --- /dev/null
>> +++ b/drivers/watchdog/starfive-wdt.c
>> @@ -0,0 +1,651 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Starfive Watchdog driver
>> + *
>> + * Copyright (C) 2022 StarFive Technology Co., Ltd.
>> + */
>> +
>> +#include <linux/clk.h>
>> +#include <linux/iopoll.h>
>> +#include <linux/module.h>
>> +#include <linux/of_device.h>
>> +#include <linux/pm_runtime.h>
>> +#include <linux/reset.h>
>> +#include <linux/watchdog.h>
>> +
>> +/* JH7110 WatchDog register define */
>> +#define STARFIVE_WDT_JH7110_LOAD 0x000 /* RW: Watchdog load register */
>> +#define STARFIVE_WDT_JH7110_VALUE 0x004 /* RO: The current value for the watchdog counter */
>> +#define STARFIVE_WDT_JH7110_CONTROL 0x008 /*
>> + * RW:
>> + * [0]: reset enable;
>> + * [1]: int enable/wdt enable/reload counter;
>> + * [31:2]: reserve.
>
> reserved
Will fix.
>
>> + */
>> +#define STARFIVE_WDT_JH7110_INTCLR 0x00c /* WO: clear intterupt && reload the counter */
>> +#define STARFIVE_WDT_JH7110_RIS 0x010 /* RO: Raw interrupt status from the counter */
>> +#define STARFIVE_WDT_JH7110_IMS 0x014 /* RO: Enabled interrupt status from the counter */
>> +#define STARFIVE_WDT_JH7110_LOCK 0xc00 /*
>> + * RO: Enable write access to all other registers
>> + * by writing 0x1ACCE551.
>> + */
>
> "RO" contradicts itself against the rest of the comment. The register is
> written to, so it can't bew RO.
Change to 'RW'.
>
>> +
>> +/* WDOGCONTROL */
>> +#define STARFIVE_WDT_ENABLE 0x1
>> +#define STARFIVE_WDT_JH7110_EN_SHIFT 0
>> +#define STARFIVE_WDT_RESET_EN 0x1
>> +#define STARFIVE_WDT_JH7110_RESEN_SHIFT 1
>> +
>> +/* WDOGLOCK */
>> +#define STARFIVE_WDT_LOCKED BIT(0)
>> +#define STARFIVE_WDT_JH7110_UNLOCK_KEY 0x1acce551
>> +
>> +/* WDOGINTCLR */
>> +#define STARFIVE_WDT_INTCLR 0x1
>> +
>> +#define STARFIVE_WDT_MAXCNT 0xffffffff
>> +#define STARFIVE_WDT_DEFAULT_TIME (15)
>> +#define STARFIVE_WDT_DELAY_US 0
>> +#define STARFIVE_WDT_TIMEOUT_US 10000
>> +
>> +/* module parameter */
>> +#define STARFIVE_WDT_EARLY_ENA 0
>> +
>> +static bool nowayout = WATCHDOG_NOWAYOUT;
>> +static int heartbeat;
>> +static int early_enable = STARFIVE_WDT_EARLY_ENA;
>> +
>> +module_param(heartbeat, int, 0);
>> +module_param(early_enable, int, 0);
>> +module_param(nowayout, bool, 0);
>> +
>> +MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. (default="
>> + __MODULE_STRING(STARFIVE_WDT_DEFAULT_TIME) ")");
>> +MODULE_PARM_DESC(early_enable,
>> + "Watchdog is started at boot time if set to 1, default="
>> + __MODULE_STRING(STARFIVE_WDT_EARLY_ENA));
>> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
>> + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
>> +
>> +struct starfive_wdt_variant {
>> + u32 control;
>> + u32 load;
>> + u32 enable;
>> + u32 value;
>> + u32 int_clr;
>> + u32 unlock;
>> + u32 unlock_key;
>> + u32 irq_is_raise;
>> + u8 enrst_shift;
>> + u8 en_shift;
>> +};
>> +
>> +struct starfive_wdt {
>> + unsigned long freq;
>> + struct device *dev;
>> + struct watchdog_device wdt_device;
>> + struct clk *core_clk;
>> + struct clk *apb_clk;
>> + struct reset_control *rsts;
>> + const struct starfive_wdt_variant *drv_data;
>> + u32 count; /*count of timeout*/
>> + u32 reload; /*restore the count*/
>> + void __iomem *base;
>> + spinlock_t lock; /* spinlock for register handling */
>> +};
>> +
>> +/* Register bias in JH7110 */
>> +static const struct starfive_wdt_variant drv_data_jh7110 = {
>> + .control = STARFIVE_WDT_JH7110_CONTROL,
>> + .load = STARFIVE_WDT_JH7110_LOAD,
>> + .enable = STARFIVE_WDT_JH7110_CONTROL,
>> + .value = STARFIVE_WDT_JH7110_VALUE,
>> + .int_clr = STARFIVE_WDT_JH7110_INTCLR,
>> + .unlock = STARFIVE_WDT_JH7110_LOCK,
>> + .unlock_key = STARFIVE_WDT_JH7110_UNLOCK_KEY,
>> + .irq_is_raise = STARFIVE_WDT_JH7110_IMS,
>> + .enrst_shift = STARFIVE_WDT_JH7110_RESEN_SHIFT,
>> + .en_shift = STARFIVE_WDT_JH7110_EN_SHIFT,
>> +};
>> +
>> +static const struct of_device_id starfive_wdt_match[] = {
>> + { .compatible = "starfive,jh7110-wdt", .data = &drv_data_jh7110 },
>> + {}
>> +};
>> +MODULE_DEVICE_TABLE(of, starfive_wdt_match);
>> +
>> +static const struct platform_device_id starfive_wdt_ids[] = {
>> + {
>> + .name = "starfive-jh7110-wdt",
>> + .driver_data = (unsigned long)&drv_data_jh7110,
>> + },
>> + {}
>> +};
>> +MODULE_DEVICE_TABLE(platform, starfive_wdt_ids);
>> +
>> +static int starfive_wdt_get_clock_rate(struct starfive_wdt *wdt)
>> +{
>> + wdt->freq = clk_get_rate(wdt->core_clk);
>> + /* The clock rate should not be 0.*/
>
> This is obvious and not worth a comment.
Will drop.
>
>> + if (wdt->freq)
>> + return 0;
>> +
>> + dev_err(wdt->dev, "get clock rate failed.\n");
>> + return -ENOENT;
>
> Error handling should come first
>
> if (!wdt->freq) {
> dev_err(wdt->dev, "get clock rate failed.\n");
> return -EINVAL;
> }
> return 0;
>
> This is not "No such file or directory" (yes, I see that other drivers
> do that, but that doesn't make it better). Use -EINVAL instead.
Will fix.
>
>> +}
>> +
>> +static int starfive_wdt_get_clock(struct starfive_wdt *wdt)
>> +{
>> + wdt->apb_clk = devm_clk_get(wdt->dev, "apb");
>> + if (IS_ERR(wdt->apb_clk)) {
>> + dev_err(wdt->dev, "failed to get apb clock.\n");
>> + return PTR_ERR(wdt->apb_clk);
>> + }
>> +
>> + wdt->core_clk = devm_clk_get(wdt->dev, "core");
>> + if (IS_ERR(wdt->core_clk)) {
>> + dev_err(wdt->dev, "failed to get core clock.\n");
>> + return PTR_ERR(wdt->core_clk);
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static int starfive_wdt_reset_init(struct starfive_wdt *wdt)
>> +{
>> + int ret = 0;
>> +
>> + wdt->rsts = devm_reset_control_array_get_exclusive(wdt->dev);
>> + if (IS_ERR(wdt->rsts)) {
>> + dev_err(wdt->dev, "failed to get rsts error.\n");
>
> I don't think this message is understandable. "failed to get reset
> control", maybe. Also, the call may return -EPROBE_DEFER,
> which should not generate an error message. Either drop the message
> or use dev_err_probe().
Thanks you for reminding me. I will drop this.
So is the devm_clk_get() and also drop the error message?
>
>> + ret = PTR_ERR(wdt->rsts);
>> + } else {
>> + ret = reset_control_deassert(wdt->rsts);
>> + if (ret)
>> + dev_err(wdt->dev, "failed to deassert rsts.\n");
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static u32 starfive_wdt_ticks_to_sec(struct starfive_wdt *wdt, u32 ticks)
>> +{
>> + return DIV_ROUND_CLOSEST(ticks, wdt->freq);
>> +}
>> +
>> +/*
>> + * Write unlock-key to unlock. Write other value to lock. When lock bit is 1,
>> + * external accesses to other watchdog registers are ignored.
>> + */
>> +static bool starfive_wdt_is_locked(struct starfive_wdt *wdt)
>> +{
>> + u32 val;
>> +
>> + val = readl(wdt->base + wdt->drv_data->unlock);
>> + return !!(val & STARFIVE_WDT_LOCKED);
>> +}
>> +
>> +static void starfive_wdt_unlock(struct starfive_wdt *wdt)
>> +{
>> + if (starfive_wdt_is_locked(wdt))
>> + writel(wdt->drv_data->unlock_key,
>> + wdt->base + wdt->drv_data->unlock);
>> +}
>> +
>> +static void starfive_wdt_lock(struct starfive_wdt *wdt)
>> +{
>> + if (!starfive_wdt_is_locked(wdt))
>> + writel(~wdt->drv_data->unlock_key,
>> + wdt->base + wdt->drv_data->unlock);
>> +}
>> +
>> +/* enable watchdog interrupt to reset/reboot */
>> +static void starfive_wdt_enable_reset(struct starfive_wdt *wdt)
>> +{
>> + u32 val;
>> +
>> + val = readl(wdt->base + wdt->drv_data->control);
>> + val |= STARFIVE_WDT_RESET_EN << wdt->drv_data->enrst_shift;
>> + writel(val, wdt->base + wdt->drv_data->control);
>> +}
>> +
>> +/* disable watchdog interrupt to reset/reboot */
>> +static void starfive_wdt_disable_reset(struct starfive_wdt *wdt)
>> +{
>> + u32 val;
>> +
>> + val = readl(wdt->base + wdt->drv_data->control);
>> + val &= ~(STARFIVE_WDT_RESET_EN << wdt->drv_data->enrst_shift);
>> + writel(val, wdt->base + wdt->drv_data->control);
>> +}
>> +
>> +/* interrupt status whether has been raised from the counter */
>> +static bool starfive_wdt_raise_irq_status(struct starfive_wdt *wdt)
>> +{
>> + return !!readl(wdt->base + wdt->drv_data->irq_is_raise);
>> +}
>> +
>> +/* clear interrupt signal before initialization or reload */
>> +static void starfive_wdt_int_clr(struct starfive_wdt *wdt)
>> +{
>> + writel(STARFIVE_WDT_INTCLR, wdt->base + wdt->drv_data->int_clr);
>> +}
>> +
>> +static inline void starfive_wdt_set_count(struct starfive_wdt *wdt, u32 val)
>> +{
>> + writel(val, wdt->base + wdt->drv_data->load);
>> +}
>> +
>> +static inline u32 starfive_wdt_get_count(struct starfive_wdt *wdt)
>> +{
>> + return readl(wdt->base + wdt->drv_data->value);
>> +}
>> +
>> +/* enable watchdog */
>> +static inline void starfive_wdt_enable(struct starfive_wdt *wdt)
>> +{
>> + u32 val;
>> +
>> + val = readl(wdt->base + wdt->drv_data->enable);
>> + val |= STARFIVE_WDT_ENABLE << wdt->drv_data->en_shift;
>> + writel(val, wdt->base + wdt->drv_data->enable);
>> +}
>> +
>> +/* disable watchdog */
>> +static inline void starfive_wdt_disable(struct starfive_wdt *wdt)
>> +{
>> + u32 val;
>> +
>> + val = readl(wdt->base + wdt->drv_data->enable);
>> + val &= ~(STARFIVE_WDT_ENABLE << wdt->drv_data->en_shift);
>> + writel(val, wdt->base + wdt->drv_data->enable);
>> +}
>> +
>> +static inline void starfive_wdt_set_reload_count(struct starfive_wdt *wdt, u32 count)
>> +{
>> + starfive_wdt_set_count(wdt, count);
>> + /* need enable controller to reload counter */
>> + starfive_wdt_enable(wdt);
>> +}
>> +
>> +static unsigned int starfive_wdt_max_timeout(struct starfive_wdt *wdt)
>> +{
>> + return DIV_ROUND_UP(STARFIVE_WDT_MAXCNT, (wdt->freq / 2)) - 1;
>> +}
>> +
>> +static unsigned int starfive_wdt_get_timeleft(struct watchdog_device *wdd)
>> +{
>> + struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
>> + u32 count;
>> +
>> + starfive_wdt_unlock(wdt);
>> + /*
>> + * Because set half count value,
>> + * timeleft value should add the count value before first timeout.
>> + */
>> + count = starfive_wdt_get_count(wdt);
>> + if (!starfive_wdt_raise_irq_status(wdt))
>> + count += wdt->count;
>> +
>> + starfive_wdt_lock(wdt);
>> +
>> + return starfive_wdt_ticks_to_sec(wdt, count);
>> +}
>> +
>> +static int starfive_wdt_keepalive(struct watchdog_device *wdd)
>> +{
>> + struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
>> +
>> + spin_lock(&wdt->lock);
>> +
>> + starfive_wdt_unlock(wdt);
>> + starfive_wdt_int_clr(wdt);
>> + starfive_wdt_set_reload_count(wdt, wdt->count);
>> + starfive_wdt_lock(wdt);
>> +
>> + spin_unlock(&wdt->lock);
>> +
>> + return 0;
>> +}
>> +
>> +static int starfive_wdt_stop(struct watchdog_device *wdd)
>> +{
>> + struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
>> +
>> + spin_lock(&wdt->lock);
>> +
>> + starfive_wdt_unlock(wdt);
>> + starfive_wdt_disable_reset(wdt);
>
> Is that necessary ? The watchdog is going to be stopped, after all.
It doesn't seem necessary. Drop this. And drop this entire function
because no one use it.
>
>> + starfive_wdt_int_clr(wdt);
>> + starfive_wdt_disable(wdt);
>> + starfive_wdt_lock(wdt);
>> +
>> + spin_unlock(&wdt->lock);
>> +
>> + return 0;
>> +}
>> +
>> +static int starfive_wdt_pm_stop(struct watchdog_device *wdd)
>> +{
>> + struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
>> +
>> + starfive_wdt_stop(wdd);
>> + pm_runtime_put_sync(wdt->dev);
>> +
>> + return 0;
>> +}
>> +
>> +static int starfive_wdt_start(struct watchdog_device *wdd)
>> +{
>> + struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
>> +
>> + spin_lock(&wdt->lock);
>> + starfive_wdt_unlock(wdt);
>> + /* disable watchdog, to be safe */
>> + starfive_wdt_disable(wdt);
>> +
>> + starfive_wdt_enable_reset(wdt);
>> + starfive_wdt_int_clr(wdt);
>> + starfive_wdt_set_count(wdt, wdt->count);
>> + starfive_wdt_enable(wdt);
>> +
>> + starfive_wdt_lock(wdt);
>> + spin_unlock(&wdt->lock);
>> +
>> + return 0;
>> +}
>> +
>> +static int starfive_wdt_pm_start(struct watchdog_device *wdd)
>> +{
>> + struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
>> +
>> + pm_runtime_get_sync(wdt->dev);
>> +
>> + return starfive_wdt_start(wdd);
>> +}
>> +
>> +static int starfive_wdt_set_timeout(struct watchdog_device *wdd,
>> + unsigned int timeout)
>> +{
>> + struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
>> + unsigned long freq = wdt->freq;
>> +
>> + spin_lock(&wdt->lock);
>> +
>> + /*
>> + * This watchdog takes twice timeouts to reset.
>> + * In order to reduce time to reset, should set half count value.
>> + */
>> + wdt->count = timeout * freq / 2;
>> + wdd->timeout = timeout;
>> +
>> + starfive_wdt_unlock(wdt);
>> + starfive_wdt_disable(wdt);
>> + starfive_wdt_set_reload_count(wdt, wdt->count);
>> + starfive_wdt_enable(wdt);
>> + starfive_wdt_lock(wdt);
>> +
>> + spin_unlock(&wdt->lock);
>> +
>> + return 0;
>> +}
>> +
>> +#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
>> +
>> +static const struct watchdog_info starfive_wdt_ident = {
>> + .options = OPTIONS,
>> + .identity = "StarFive Watchdog",
>> +};
>> +
>> +static const struct watchdog_ops starfive_wdt_ops = {
>> + .owner = THIS_MODULE,
>> + .start = starfive_wdt_pm_start,
>> + .stop = starfive_wdt_pm_stop,
>> + .ping = starfive_wdt_keepalive,
>> + .set_timeout = starfive_wdt_set_timeout,
>> + .get_timeleft = starfive_wdt_get_timeleft,
>> +};
>> +
>> +static const struct watchdog_device starfive_wdd = {
>> + .info = &starfive_wdt_ident,
>> + .ops = &starfive_wdt_ops,
>> + .timeout = STARFIVE_WDT_DEFAULT_TIME,
>> +};
>> +
>> +static inline const struct starfive_wdt_variant *
>> +starfive_wdt_get_drv_data(struct platform_device *pdev)
>> +{
>> + const struct starfive_wdt_variant *variant;
>> +
>> + variant = of_device_get_match_data(&pdev->dev);
>> + if (!variant) {
>> + /* Device matched by platform_device_id */
>> + variant = (struct starfive_wdt_variant *)
>> + platform_get_device_id(pdev)->driver_data;
>> + }
>> +
>> + return variant;
>> +}
>> +
>> +static int starfive_wdt_probe(struct platform_device *pdev)
>> +{
>> + struct device *dev = &pdev->dev;
>> + struct starfive_wdt *wdt;
>> + int ret;
>> +
>> + wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
>> + if (!wdt)
>> + return -ENOMEM;
>> +
>> + wdt->dev = dev;
>> + spin_lock_init(&wdt->lock);
>> + wdt->wdt_device = starfive_wdd;
>> +
>> + wdt->drv_data = starfive_wdt_get_drv_data(pdev);
>> +
>> + /* get the memory region for the watchdog timer */
>> + wdt->base = devm_platform_ioremap_resource(pdev, 0);
>> + if (IS_ERR(wdt->base)) {
>> + ret = PTR_ERR(wdt->base);
>> + return ret;
>> + }
>> +
>> + platform_set_drvdata(pdev, wdt);
>> + pm_runtime_enable(wdt->dev);
>> +
>> + ret = starfive_wdt_get_clock(wdt);
>> + if (ret)
>> + return ret;
>> +
>> + if (pm_runtime_enabled(wdt->dev)) {
>> + ret = pm_runtime_get_sync(wdt->dev);
>> + if (ret < 0)
>> + return ret;
>> + } else {
>> + /* runtime PM is disabled but clocks need to be enabled */
>> + ret = clk_prepare_enable(wdt->apb_clk);
>> + if (ret) {
>> + dev_err(wdt->dev, "failed to enable apb_clk.\n");
>> + return ret;
>> + }
>> + ret = clk_prepare_enable(wdt->core_clk);
>> + if (ret) {
>> + dev_err(wdt->dev, "failed to enable core_clk.\n");
>> + goto err_apb_clk_disable;
>> + }
>> + }
>> +
>> + ret = starfive_wdt_get_clock_rate(wdt);
>> + if (ret)
>> + goto err_clk_disable;
>> +
>> + ret = starfive_wdt_reset_init(wdt);
>> + if (ret)
>> + goto err_clk_disable;
>> +
>> + wdt->wdt_device.min_timeout = 1;
>> + wdt->wdt_device.max_timeout = starfive_wdt_max_timeout(wdt);
>
> wdt->wdt_device.timeout = STARFIVE_WDT_DEFAULT_TIME;
>
> should be set here. Otherwise the warning below would always be seen
> if the module parameter is not set.
>
>> +
>> + watchdog_set_drvdata(&wdt->wdt_device, wdt);
>> +
>> + /*
>> + * see if we can actually set the requested heartbeat,
>> + * and if not, try the default value.
>> + */
>> + watchdog_init_timeout(&wdt->wdt_device, heartbeat, dev);
>> + if (wdt->wdt_device.timeout == 0 ||
>
> If wdt->wdt_device.timeout is pre-initialized, it will never be 0 here.
>
>> + wdt->wdt_device.timeout > wdt->wdt_device.max_timeout) {
>
> That won't happen because watchdog_init_timeout() validates it and does
> not update the value if it is out of range.
>
>> + dev_warn(dev, "heartbeat value out of range, default %d used\n",
>> + STARFIVE_WDT_DEFAULT_TIME);
>> + wdt->wdt_device.timeout = STARFIVE_WDT_DEFAULT_TIME;
>
> And this is then unnecessary. wdt->wdt_device.timeout will always be
> valid if it was pre-initialized.
It is changed to be this at beginning of the driver:
static int heartbeat = STARFIVE_WDT_DEFAULT_TIME;
and it is changed to be this here:
ret = watchdog_init_timeout(&wdt->wdt_device, heartbeat, dev);
if (ret)
return ret;
Would that be better?
>
>> + }
>> + starfive_wdt_set_timeout(&wdt->wdt_device, wdt->wdt_device.timeout);
>> +
>> + watchdog_set_nowayout(&wdt->wdt_device, nowayout);
>> + watchdog_stop_on_reboot(&wdt->wdt_device);
>> + watchdog_stop_on_unregister(&wdt->wdt_device);
>> +
>> + wdt->wdt_device.parent = dev;
>> +
>> + ret = watchdog_register_device(&wdt->wdt_device);
>> + if (ret)
>> + goto err_clk_disable;
>> +
>> + if (early_enable) {
>> + starfive_wdt_start(&wdt->wdt_device);
>> + set_bit(WDOG_HW_RUNNING, &wdt->wdt_device.status);
>
> Is it correct to call pm_runtime_put_sync() below if the watchdog
> is running ? Doesn't that stop the clock ?
Add a check of 'early_enable' to pm_runtime_put_sync() or
move it after starfive_wdt_stop() immediately.
>
>> + } else {
>> + starfive_wdt_stop(&wdt->wdt_device);
>> + }
>
> Wrong order. This has to be done _before_ the watchdog device is registered
> to make sure that the watchdog core knows about WDOG_HW_RUNNING.
So move this before watchdog_register_device().
Best regards,
Xingyu Wu
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