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Date: Fri, 2 Dec 2022 07:08:07 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: "xingu.wu" <xingyu.wu@...rfivetech.com>,
linux-riscv@...ts.infradead.org, devicetree@...r.kernel.org,
linux-watchdog@...r.kernel.org,
Wim Van Sebroeck <wim@...ux-watchdog.org>
Cc: Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.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
Subject: Re: [PATCH v1 2/3] drivers: watchdog: Add StarFive Watchdog driver
On 12/2/22 01:39, xingu.wu wrote:
> From: Xingyu Wu <xingyu.wu@...rfivetech.com>
>
> Add watchdog driver for the StarFive JH7110 SoC.
>
> Signed-off-by: Xingyu Wu <xingyu.wu@...rfivetech.com>
> ---
> MAINTAINERS | 7 +
> drivers/watchdog/Kconfig | 11 +
> drivers/watchdog/Makefile | 3 +
> drivers/watchdog/starfive-wdt.c | 854 ++++++++++++++++++++++++++++++++
> 4 files changed, 875 insertions(+)
> create mode 100644 drivers/watchdog/starfive-wdt.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a70c1d0f303e..133214dd2f60 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -19623,6 +19623,13 @@ F: Documentation/devicetree/bindings/reset/starfive,jh7100-reset.yaml
> F: drivers/reset/starfive/
> F: include/dt-bindings/reset/starfive*
>
> +STARFIVE 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 b64bc49c7f30..658fc9fef4fa 100644
> --- a/drivers/watchdog/Kconfig
> +++ b/drivers/watchdog/Kconfig
> @@ -2082,6 +2082,17 @@ config UML_WATCHDOG
> tristate "UML watchdog"
> depends on UML || COMPILE_TEST
>
> +# RISCV Architecture
> +
> +config STARFIVE_WATCHDOG
> + tristate "StarFive Watchdog support"
> + depends on RISCV
> + select WATCHDOG_CORE
> + default SOC_STARFIVE
> + help
> + Say Y here to support the StarFive watchdog. 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 d41e5f830ae7..9c22f1a43d5c 100644
> --- a/drivers/watchdog/Makefile
> +++ b/drivers/watchdog/Makefile
> @@ -210,6 +210,9 @@ obj-$(CONFIG_WATCHDOG_SUN4V) += sun4v_wdt.o
> # Xen
> obj-$(CONFIG_XEN_WDT) += xen_wdt.o
>
> +# RISCV Architecture
> +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..dcb6e693ba6c
> --- /dev/null
> +++ b/drivers/watchdog/starfive-wdt.c
> @@ -0,0 +1,854 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Starfive Watchdog driver
> + *
> + * Copyright (C) 2022 StarFive Technology Co., Ltd.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/iopoll.h>
> +#include <linux/module.h>
> +#include <linux/moduleparam.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/reset.h>
> +#include <linux/reset-controller.h>
> +#include <linux/slab.h>
> +#include <linux/timer.h>
> +#include <linux/types.h>
> +#include <linux/uaccess.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]: res.
> + */
> +#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.
> + */
> +#define STARFIVE_WDT_JH7110_ITCR 0xf00 /*
> + * RW: When set HIGH,
> + * places the Watchdog into integraeion test mode.\\intetration
> + */
> +#define STARFIVE_WDT_JH7110_ITOP 0xf04 /*
> + * WO: [0] WDOGRES value Integration Test Mode.
> + * Value output on WDOGRES when in
> + * Integration Test Mode.
> + * [1] Integration Test WDOGINT value.
> + * Value output on WDOGINT when in
> + * Integration Test Mode.
> + */
> +
> +#define STARFIVE_WDT_JH7110_UNLOCK_KEY 0x1acce551
> +#define STARFIVE_WDT_JH7110_RESEN_SHIFT 1
> +#define STARFIVE_WDT_JH7110_EN_SHIFT 0
> +#define STARFIVE_WDT_JH7110_INT_EN_SHIFT STARFIVE_WDT_JH7110_EN_SHIFT
> +
> +/* WDOGCONTROL */
> +#define STARFIVE_WDT_INT_EN 0x0
> +#define STARFIVE_WDT_INT_DIS BIT(0)
> +#define STARFIVE_WDT_RESET_EN 0x1
> +
> +/* WDOGLOCK */
> +#define STARFIVE_WDT_LOCKED BIT(0)
> +
> +#define STARFIVE_WDT_INTCLR 0x1
> +#define STARFIVE_WDT_ENABLE 0x1
> +#define STARFIVE_WDT_ATBOOT 0x0
> +#define STARFIVE_WDT_MAXCNT 0xffffffff
> +
> +#define STARFIVE_WDT_DEFAULT_TIME (15)
> +#define STARFIVE_WDT_DELAY_US 0
> +#define STARFIVE_WDT_TIMEOUT_US 10000
> +
> +static bool nowayout = WATCHDOG_NOWAYOUT;
> +static int tmr_margin;
> +static int tmr_atboot = STARFIVE_WDT_ATBOOT;
> +static int soft_noboot;
> +
> +module_param(tmr_margin, int, 0);
> +module_param(tmr_atboot, int, 0);
> +module_param(nowayout, bool, 0);
> +module_param(soft_noboot, int, 0);
> +
> +MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. (default="
> + __MODULE_STRING(STARFIVE_WDT_DEFAULT_TIME) ")");
> +MODULE_PARM_DESC(tmr_atboot,
> + "Watchdog is started at boot time if set to 1, default="
> + __MODULE_STRING(STARFIVE_WDT_ATBOOT));
> +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
> + __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> +MODULE_PARM_DESC(soft_noboot,
> + "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default 0)");
> +
> +struct starfive_wdt_variant_t {
> + u32 unlock_key;
> + u8 enrst_shift;
> + u8 en_shift;
> + u8 intclr_check;
> + u8 intclr_ava_shift;
> +};
> +
> +struct starfive_wdt_variant {
> + u32 control;
> + u32 load;
> + u32 enable;
> + u32 reload;
> + u32 value;
> + u32 int_clr;
> + u32 int_mask;
> + u32 unlock;
> + u32 enter_irq_status;
> + struct starfive_wdt_variant_t *variant;
> +};
> +
> +struct starfive_wdt {
> + u64 freq;
clk_get_rate() returns unsigned long. Why would u64 be needed here ?
> + 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 */
> +
> + int irq;
> +};
> +
> +#ifdef CONFIG_OF
> +static struct starfive_wdt_variant_t jh7110_variant = {
> + .unlock_key = STARFIVE_WDT_JH7110_UNLOCK_KEY,
> + .enrst_shift = STARFIVE_WDT_JH7110_RESEN_SHIFT,
> + .en_shift = STARFIVE_WDT_JH7110_EN_SHIFT,
> +};
> +
> +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,
> + .enter_irq_status = STARFIVE_WDT_JH7110_IMS,
> + .variant = &jh7110_variant,
> +};
> +
If there is no specific reason for all that complexity, drop it and introduce
it if/when necessary.
> +static const struct of_device_id starfive_wdt_match[] = {
> + { .compatible = "starfive,jh7110-wdt", .data = &drv_data_jh7110 },
> + {}
> +};
> +MODULE_DEVICE_TABLE(of, starfive_wdt_match);
> +#endif
> +
> +static const struct platform_device_id starfive_wdt_ids[] = {
> + {
> + .name = "starfive-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)
> +{
> + int ret;
> + u32 freq;
> +
> + if (!IS_ERR(wdt->core_clk)) {
> + wdt->freq = clk_get_rate(wdt->core_clk);
> + return 0;
> + }
> + dev_dbg(wdt->dev, "get rate failed, need clock-frequency define in dts.\n");
> +
> + /* Next we try to get clock-frequency from dts.*/
> + ret = of_property_read_u32(wdt->dev->of_node, "clock-frequency", &freq);
> + if (!ret) {
> + wdt->freq = (u64)freq;
Unnecessary typecast.
> + return 0;
> + }
> + dev_err(wdt->dev, "get clock-frequency failed\n");
> +
> + return -ENOENT;
> +}
I have never seen this kind of code before. Why would it be needed ?
> +
> +static int starfive_wdt_enable_clock(struct starfive_wdt *wdt)
> +{
> + int ret = 0;
> +
> + wdt->apb_clk = devm_clk_get(wdt->dev, "apb_clk");
> + if (!IS_ERR(wdt->apb_clk)) {
> + ret = clk_prepare_enable(wdt->apb_clk);
> + if (ret) {
> + dev_err(wdt->dev, "failed to enable apb_clk.\n");
> + goto err;
> + }
> + } else {
> + dev_err(wdt->dev, "failed to get apb_clk.\n");
> + ret = PTR_ERR(wdt->apb_clk);
> + goto err;
> + }
Why not use devm_clk_get_enabled() ?
> +
> + wdt->core_clk = devm_clk_get(wdt->dev, "core_clk");
> + if (!IS_ERR(wdt->core_clk)) {
> + ret = clk_prepare_enable(wdt->core_clk);
> + if (ret) {
> + dev_err(wdt->dev, "failed to enable core_clk.\n");
> + goto err;
> + }
> + } else {
> + dev_err(wdt->dev, "failed to get core_clk.\n");
> + ret = PTR_ERR(wdt->core_clk);
> + goto err;
> + }
> +
> + return 0;
> +
> +err:
> + return ret;
Unnecessary. Return directly.
> +}
> +
> +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)) {
> + ret = reset_control_deassert(wdt->rsts);
> + if (ret) {
> + dev_err(wdt->dev, "failed to deassert rsts.\n");
> + goto err;
> + }
> + } else {
> + dev_err(wdt->dev, "failed to get rsts error.\n");
failed ... error is redundant. Drop "errror".
> + ret = PTR_ERR(wdt->rsts);
> + goto err;
> + }
> +
> + return 0;
> +
> +err:
> + return ret;
Unnecessary. Return directly.
> +}
> +
> +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 int starfive_wdt_is_locked(struct starfive_wdt *wdt)
bool ?
> +{
> + 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->variant->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->variant->unlock_key,
> + wdt->base + wdt->drv_data->unlock);
> +}
> +
> +/* enable watchdog interrupt */
> +static inline void starfive_wdt_int_enable(struct starfive_wdt *wdt)
> +{
> + u32 val;
> +
> + if (wdt->drv_data->int_mask) {
> + val = readl(wdt->base + wdt->drv_data->int_mask);
> + val &= ~STARFIVE_WDT_INT_DIS;
> + writel(val, wdt->base + wdt->drv_data->int_mask);
> + }
> +}
> +
> +/* disable watchdog interrupt */
> +static inline void starfive_wdt_int_disable(struct starfive_wdt *wdt)
> +{
> + u32 val;
> +
> + if (wdt->drv_data->int_mask) {
> + val = readl(wdt->base + wdt->drv_data->int_mask);
> + val |= STARFIVE_WDT_INT_DIS;
> + writel(val, wdt->base + wdt->drv_data->int_mask);
> + }
> +}
> +
> +/* enable watchdog interrupt to reset */
> +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->variant->enrst_shift;
> + writel(val, wdt->base + wdt->drv_data->control);
> +}
> +
> +/* disable watchdog interrupt to reset */
> +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->variant->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->enter_irq_status);
> +}
> +
> +static void starfive_wdt_int_clr(struct starfive_wdt *wdt)
> +{
> + void __iomem *addr;
> + u8 clr_check;
> + u8 clr_ava_shift;
> + u32 value;
> + int ret = 0;
> +
> + addr = wdt->base + wdt->drv_data->int_clr;
> + clr_ava_shift = wdt->drv_data->variant->intclr_ava_shift;
> + clr_check = wdt->drv_data->variant->intclr_check;
> + if (clr_check) {
> + /* waiting interrupt can be to clearing */
> + value = readl(addr);
> + ret = readl_poll_timeout_atomic(addr, value,
> + !(value & BIT(clr_ava_shift)),
> + STARFIVE_WDT_DELAY_US, STARFIVE_WDT_TIMEOUT_US);
> + }
> +
> + if (!ret)
> + writel(STARFIVE_WDT_INTCLR, addr);
> +
> + if (starfive_wdt_raise_irq_status(wdt))
> + enable_irq(wdt->irq);
> +}
> +
> +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);
> +}
> +
> +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->variant->en_shift;
> + writel(val, wdt->base + wdt->drv_data->enable);
> +}
> +
> +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->variant->en_shift);
> + writel(val, wdt->base + wdt->drv_data->enable);
> +}
> +
> +static inline void starfive_wdt_set_relod_count(struct starfive_wdt *wdt, u32 count)
> +{
> + writel(count, wdt->base + wdt->drv_data->load);
> + if (wdt->drv_data->reload)
> + writel(0x1, wdt->base + wdt->drv_data->reload);
> + else
> + /* jh7110 need enable controller to reload counter */
> + starfive_wdt_enable(wdt);
> +}
> +
> +static void starfive_wdt_mask_and_disable_reset(struct starfive_wdt *wdt, bool mask)
> +{
> + starfive_wdt_unlock(wdt);
> +
> + if (mask)
> + starfive_wdt_disable_reset(wdt);
> + else
> + starfive_wdt_enable_reset(wdt);
> +
> + starfive_wdt_lock(wdt);
> +}
> +
> +static unsigned int starfive_wdt_max_timeout(struct starfive_wdt *wdt)
> +{
> + return DIV_ROUND_UP(STARFIVE_WDT_MAXCNT, wdt->freq) - 1;
> +}
> +
> +static unsigned int starfive_wdt_get_timeleft(struct watchdog_device *wdd)
> +{
> + struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
> + u32 count;
> + u32 irq_status;
> +
> + starfive_wdt_unlock(wdt);
> + /*
> + * Because set half count value,
> + * timeleft value should add the count value before first timeout.
> + */
> + irq_status = starfive_wdt_raise_irq_status(wdt) ? 1 : 0;
> + count = starfive_wdt_get_count(wdt) + (1 - irq_status) * 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_relod_count(wdt, wdt->count);
> + starfive_wdt_lock(wdt);
> +
> + spin_unlock(&wdt->lock);
> +
> + return 0;
> +}
> +
> +static irqreturn_t starfive_wdt_interrupt_handler(int irq, void *data)
> +{
> + /*
> + * We don't clear the IRQ status. It's supposed to be done by the
> + * following ping operations.
> + */
> + struct platform_device *pdev = data;
> + struct starfive_wdt *wdt = platform_get_drvdata(pdev);
> +
> + /* Disable the IRQ and avoid re-entry interrupt. */
> + disable_irq_nosync(wdt->irq);
> +
> + return IRQ_HANDLED;
> +}
What is the purpose of this interrupt ? It doesn't add any value
as implemented.
> +
> +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_int_disable(wdt);
> + 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(wdt->dev);
> +
> + return 0;
> +}
> +
> +static int starfive_wdt_start(struct watchdog_device *wdd)
> +{
> + struct starfive_wdt *wdt = watchdog_get_drvdata(wdd);
> +
> + pm_runtime_get_sync(wdt->dev);
> +
> + spin_lock(&wdt->lock);
> +
> + starfive_wdt_unlock(wdt);
> +
> + if (soft_noboot)
> + starfive_wdt_disable_reset(wdt);
> + else
> + starfive_wdt_enable_reset(wdt);
> +
> + starfive_wdt_int_clr(wdt);
> + starfive_wdt_set_count(wdt, wdt->count);
> + starfive_wdt_int_enable(wdt);
> + starfive_wdt_enable(wdt);
> +
> + starfive_wdt_lock(wdt);
> +
> + spin_unlock(&wdt->lock);
> +
> + return 0;
> +}
> +
> +static int starfive_wdt_restart(struct watchdog_device *wdd, unsigned long action,
> + void *data)
> +{
> + 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);
> +
> + if (soft_noboot)
> + starfive_wdt_disable_reset(wdt);
> + else
> + starfive_wdt_enable_reset(wdt);
> +
> + /* put initial values into count and data */
> + starfive_wdt_set_count(wdt, wdt->count);
This is supposed to reset the system. Why write wdt->count
instead of 0 or 1 ?
> +
> + /* set the watchdog to go and reset... */
> + starfive_wdt_int_clr(wdt);
> + starfive_wdt_int_enable(wdt);
> + starfive_wdt_enable(wdt);
> +
> + starfive_wdt_lock(wdt);
> + spin_unlock(&wdt->lock);
> +
> + return 0;
> +}
> +
> +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;
> + unsigned int count;
> +
> + spin_lock(&wdt->lock);
> +
> + if (timeout < 1)
> + return -EINVAL;
Can not happen if configured properly, ie if min_timeout is set *which it is).
> +
> + /*
> + * This watchdog takes twice timeouts to reset.
> + * In order to reduce time to reset, should set half count value.
> + */
> + count = timeout * freq / 2;
> +
> + if (count > STARFIVE_WDT_MAXCNT) {
> + dev_warn(wdt->dev, "timeout %d too big,use the MAX-timeout set.\n",
> + timeout);
> + timeout = starfive_wdt_max_timeout(wdt);
> + count = timeout * freq;
> + }
> +
> + dev_info(wdt->dev, "Heartbeat: timeout=%d, count/2=%d (%08x)\n",
> + timeout, count, count);
> +
> + starfive_wdt_unlock(wdt);
> + starfive_wdt_disable(wdt);
> + starfive_wdt_set_relod_count(wdt, count);
> + starfive_wdt_enable(wdt);
> + starfive_wdt_lock(wdt);
> +
> + wdt->count = count;
> + wdd->timeout = timeout;
> +
> + spin_unlock(&wdt->lock);
> +
> + return 0;
> +}
> +
> +#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
> +
> +static const struct watchdog_info starfive_wdt_ident = {
> + .options = OPTIONS,
> + .firmware_version = 0,
> + .identity = "StarFive Watchdog",
> +};
> +
> +static const struct watchdog_ops starfive_wdt_ops = {
> + .owner = THIS_MODULE,
> + .start = starfive_wdt_start,
> + .stop = starfive_wdt_pm_stop,
> + .ping = starfive_wdt_keepalive,
> + .set_timeout = starfive_wdt_set_timeout,
> + .restart = starfive_wdt_restart,
> + .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 started = 0;
> + int ret;
> +
> + pm_runtime_enable(dev);
> +
> + 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);
> +
> + wdt->irq = platform_get_irq(pdev, 0);
> + if (wdt->irq < 0) {
> + dev_err(dev, "can not find irq.\n");
> + return wdt->irq;
> + }
> +
> + /* 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);
> + goto err;
> + }
> +
> + ret = starfive_wdt_enable_clock(wdt);
> + if (ret)
> + goto err;
> +
> + starfive_wdt_get_clock_rate(wdt);
> +
This can fail, leaving the clock rate uninitialized.
> + ret = starfive_wdt_reset_init(wdt);
> + if (ret)
> + goto err;
> +
> + wdt->wdt_device.min_timeout = 1;
> + wdt->wdt_device.max_timeout = starfive_wdt_max_timeout(wdt);
> +
> + watchdog_set_drvdata(&wdt->wdt_device, wdt);
> +
> + /*
> + * see if we can actually set the requested timer margin,
> + * and if not, try the default value.
> + */
> + watchdog_init_timeout(&wdt->wdt_device, tmr_margin, dev);
> +
> + ret = starfive_wdt_set_timeout(&wdt->wdt_device,
> + wdt->wdt_device.timeout);
> + if (ret) {
> + dev_err(dev, "tmr_margin value out of range, default %d used\n",
> + STARFIVE_WDT_DEFAULT_TIME);
> + starfive_wdt_set_timeout(&wdt->wdt_device,
> + STARFIVE_WDT_DEFAULT_TIME);
> + }
> +
> + ret = devm_request_irq(dev, wdt->irq, starfive_wdt_interrupt_handler, 0,
> + pdev->name, pdev);
> + if (ret != 0) {
> + dev_err(dev, "failed to install irq (%d)\n", ret);
> + goto err;
> + }
> +
That interrupt seems pointless.
> + watchdog_set_nowayout(&wdt->wdt_device, nowayout);
> + watchdog_set_restart_priority(&wdt->wdt_device, 128);
> +
> + wdt->wdt_device.parent = dev;
> +
> + ret = watchdog_register_device(&wdt->wdt_device);
> + if (ret)
> + goto err;
> +
> + starfive_wdt_mask_and_disable_reset(wdt, false);
> +
> + if (tmr_atboot && started == 0) {
> + starfive_wdt_start(&wdt->wdt_device);
> + } else if (!tmr_atboot) {
> + /*
> + *if we're not enabling the watchdog, then ensure it is
> + * disabled if it has been left running from the bootloader
> + * or other source.
> + */
> + starfive_wdt_stop(&wdt->wdt_device);
> + }
This should be done before registering the watdhdog, and the watchdog core
should be informed if the watchdog is running.
> +
> +#ifdef CONFIG_PM
> + clk_disable_unprepare(wdt->core_clk);
> + clk_disable_unprepare(wdt->apb_clk);
> +#endif
> +
> + platform_set_drvdata(pdev, wdt);
> +
> + return 0;
> +
> +err:
> + return ret;
This is never acceptable. Return directly.
> +}
> +
> +static int starfive_wdt_remove(struct platform_device *dev)
> +{
> + struct starfive_wdt *wdt = platform_get_drvdata(dev);
> +
> + starfive_wdt_mask_and_disable_reset(wdt, true);
> + watchdog_unregister_device(&wdt->wdt_device);
> +
> + clk_disable_unprepare(wdt->core_clk);
> + clk_disable_unprepare(wdt->apb_clk);
> + pm_runtime_disable(wdt->dev);
This is potentially unbalanced. I would suggest to use
watchdog_stop_on_unregister().
> +
> + return 0;
> +}
> +
> +static void starfive_wdt_shutdown(struct platform_device *dev)
> +{
> + struct starfive_wdt *wdt = platform_get_drvdata(dev);
> +
> + starfive_wdt_mask_and_disable_reset(wdt, true);
> +
> + starfive_wdt_pm_stop(&wdt->wdt_device);
Use watchdog_stop_on_reboot().
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int starfive_wdt_suspend(struct device *dev)
> +{
> + int ret;
> + struct starfive_wdt *wdt = dev_get_drvdata(dev);
> +
> + starfive_wdt_unlock(wdt);
> +
> + /* Save watchdog state, and turn it off. */
> + wdt->reload = starfive_wdt_get_count(wdt);
> +
> + starfive_wdt_mask_and_disable_reset(wdt, true);
> +
> + /* Note that WTCNT doesn't need to be saved. */
> + starfive_wdt_stop(&wdt->wdt_device);
> + pm_runtime_force_suspend(dev);
> +
> + starfive_wdt_lock(wdt);
> +
> + return 0;
> +}
> +
> +static int starfive_wdt_resume(struct device *dev)
> +{
> + int ret;
> + struct starfive_wdt *wdt = dev_get_drvdata(dev);
> +
> + starfive_wdt_unlock(wdt);
> +
> + pm_runtime_force_resume(dev);
> +
> + /* Restore watchdog state. */
> + starfive_wdt_set_relod_count(wdt, wdt->reload);
> +
> + starfive_wdt_restart(&wdt->wdt_device, 0, NULL);
> +
> + starfive_wdt_mask_and_disable_reset(wdt, false);
> +
> + starfive_wdt_lock(wdt);
> +
> + return 0;
> +}
> +#endif /* CONFIG_PM_SLEEP */
> +
> +#ifdef CONFIG_PM
> +static int starfive_wdt_runtime_suspend(struct device *dev)
> +{
> + struct starfive_wdt *wdt = dev_get_drvdata(dev);
> +
> + clk_disable_unprepare(wdt->apb_clk);
> + clk_disable_unprepare(wdt->core_clk);
> +
> + return 0;
> +}
> +
> +static int starfive_wdt_runtime_resume(struct device *dev)
> +{
> + struct starfive_wdt *wdt = dev_get_drvdata(dev);
> + int ret;
> +
> + ret = clk_prepare_enable(wdt->apb_clk);
> + if (ret) {
> + dev_err(wdt->dev, "failed to enable apb_clk.\n");
> + goto err;
> + }
> +
> + ret = clk_prepare_enable(wdt->core_clk);
> + if (ret) {
> + dev_err(wdt->dev, "failed to enable core_clk.\n");
> + goto err;
> + }
> +
> + return 0;
> +
> +err:
> + return ret;
> +}
> +#endif /* CONFIG_PM */
> +
> +static const struct dev_pm_ops starfive_wdt_pm_ops = {
> + SET_RUNTIME_PM_OPS(starfive_wdt_runtime_suspend, starfive_wdt_runtime_resume, NULL)
> + SET_SYSTEM_SLEEP_PM_OPS(starfive_wdt_suspend, starfive_wdt_resume)
> +};
> +
> +static struct platform_driver starfive_wdt_driver = {
> + .probe = starfive_wdt_probe,
> + .remove = starfive_wdt_remove,
> + .shutdown = starfive_wdt_shutdown,
> + .id_table = starfive_wdt_ids,
> + .driver = {
> + .name = "starfive-wdt",
> + .pm = &starfive_wdt_pm_ops,
> + .of_match_table = of_match_ptr(starfive_wdt_match),
> + },
> +};
> +
> +module_platform_driver(starfive_wdt_driver);
> +
> +MODULE_AUTHOR("Xingyu Wu <xingyu.wu@...rfivetech.com>");
> +MODULE_AUTHOR("Samin Guo <samin.guo@...rfivetech.com>");
> +MODULE_DESCRIPTION("StarFive Watchdog Device Driver");
> +MODULE_LICENSE("GPL v2");
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