+
+#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.
