[PATCH 2/3] watchdog: sama5d4_wdt: Refactor the driver
Balakrishnan Sambath
balakrishnan.s at microchip.com
Thu Feb 26 23:31:15 PST 2026
From: Andrei Simion <andrei.simion at microchip.com>
This patch cleans up and refactors the Atmel SAMA5D4 Watchdog Driver
to be more readable and to fixup Reset issue introduced
by commit 266da53c35fc ("watchdog: sama5d4: readout initial state").
Signed-off-by: Andrei Simion <andrei.simion at microchip.com>
[Use per-device WDDIS mask and sync MR shadow WDDIS state]
Signed-off-by: Balakrishnan Sambath <balakrishnan.s at microchip.com>
---
drivers/watchdog/sama5d4_wdt.c | 156 ++++++++++++++++-----------------
1 file changed, 77 insertions(+), 79 deletions(-)
diff --git a/drivers/watchdog/sama5d4_wdt.c b/drivers/watchdog/sama5d4_wdt.c
index 13e72918338a..b422d0bd75f9 100644
--- a/drivers/watchdog/sama5d4_wdt.c
+++ b/drivers/watchdog/sama5d4_wdt.c
@@ -24,44 +24,58 @@
#define WDT_DEFAULT_TIMEOUT MAX_WDT_TIMEOUT
#define WDT_SEC2TICKS(s) ((s) ? (((s) << 8) - 1) : 0)
struct sama5d4_wdt {
struct watchdog_device wdd;
void __iomem *reg_base;
u32 mr;
u32 ir;
+ u32 wddis_mask;
unsigned long last_ping;
bool need_irq;
- bool sam9x60_support;
+ bool is_modern_chip;
};
+static inline bool wdt_enabled(struct sama5d4_wdt *wdt, u32 mr)
+{
+ return !(mr & wdt->wddis_mask);
+}
+
static int wdt_timeout;
static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(wdt_timeout, int, 0);
MODULE_PARM_DESC(wdt_timeout,
"Watchdog timeout in seconds. (default = "
__MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout,
"Watchdog cannot be stopped once started (default="
__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
-#define wdt_enabled (!(wdt->mr & AT91_WDT_WDDIS))
#define wdt_read(wdt, field) \
readl_relaxed((wdt)->reg_base + (field))
/* 4 slow clock periods is 4/32768 = 122.07µs*/
#define WDT_DELAY usecs_to_jiffies(123)
+static bool check_is_modern_chip_by_compatible(struct device *dev)
+{
+ if (of_device_is_compatible(dev->of_node, "microchip,sam9x60-wdt") ||
+ of_device_is_compatible(dev->of_node, "microchip,sama7g5-wdt"))
+ return true;
+
+ return false;
+}
+
static void wdt_write(struct sama5d4_wdt *wdt, u32 field, u32 val)
{
/*
* WDT_CR and WDT_MR must not be modified within three slow clock
* periods following a restart of the watchdog performed by a write
* access in WDT_CR.
*/
while (time_before(jiffies, wdt->last_ping + WDT_DELAY))
usleep_range(30, 125);
@@ -71,322 +85,306 @@ static void wdt_write(struct sama5d4_wdt *wdt, u32 field, u32 val)
static void wdt_write_nosleep(struct sama5d4_wdt *wdt, u32 field, u32 val)
{
if (time_before(jiffies, wdt->last_ping + WDT_DELAY))
udelay(123);
writel_relaxed(val, wdt->reg_base + field);
wdt->last_ping = jiffies;
}
-static int sama5d4_wdt_start(struct watchdog_device *wdd)
+static int wdt_start(struct watchdog_device *wdd)
{
struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
- if (wdt->sam9x60_support) {
- writel_relaxed(wdt->ir, wdt->reg_base + AT91_SAM9X60_IER);
- wdt->mr &= ~AT91_SAM9X60_WDDIS;
- } else {
- wdt->mr &= ~AT91_WDT_WDDIS;
- }
+ if (wdt->is_modern_chip)
+ writel_relaxed(wdt->ir, wdt->reg_base + AT91_WDT_IER);
+ wdt->mr &= ~wdt->wddis_mask;
wdt_write(wdt, AT91_WDT_MR, wdt->mr);
return 0;
}
-static int sama5d4_wdt_stop(struct watchdog_device *wdd)
+static int wdt_stop(struct watchdog_device *wdd)
{
struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
- if (wdt->sam9x60_support) {
- writel_relaxed(wdt->ir, wdt->reg_base + AT91_SAM9X60_IDR);
- wdt->mr |= AT91_SAM9X60_WDDIS;
- } else {
- wdt->mr |= AT91_WDT_WDDIS;
- }
+ if (wdt->is_modern_chip)
+ writel_relaxed(wdt->ir, wdt->reg_base + AT91_WDT_IDR);
+ wdt->mr |= wdt->wddis_mask;
wdt_write(wdt, AT91_WDT_MR, wdt->mr);
return 0;
}
-static int sama5d4_wdt_ping(struct watchdog_device *wdd)
+static int wdt_ping(struct watchdog_device *wdd)
{
struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
wdt_write(wdt, AT91_WDT_CR, AT91_WDT_KEY | AT91_WDT_WDRSTT);
return 0;
}
-static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd,
- unsigned int timeout)
+static int wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int timeout)
{
struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
u32 value = WDT_SEC2TICKS(timeout);
- if (wdt->sam9x60_support) {
- wdt_write(wdt, AT91_SAM9X60_WLR,
- AT91_SAM9X60_SET_COUNTER(value));
+ if (wdt->is_modern_chip) {
+ wdt_write(wdt, AT91_WDT_WLR,
+ AT91_WDT_SET_COUNTER(value));
wdd->timeout = timeout;
return 0;
}
wdt->mr &= ~AT91_WDT_WDV;
wdt->mr |= AT91_WDT_SET_WDV(value);
/*
* WDDIS has to be 0 when updating WDD/WDV. The datasheet states: When
* setting the WDDIS bit, and while it is set, the fields WDV and WDD
* must not be modified.
* If the watchdog is enabled, then the timeout can be updated. Else,
* wait that the user enables it.
*/
- if (wdt_enabled)
- wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~AT91_WDT_WDDIS);
+ if (wdt_enabled(wdt, wdt->mr))
+ wdt_write(wdt, AT91_WDT_MR, wdt->mr & ~wdt->wddis_mask);
wdd->timeout = timeout;
return 0;
}
static const struct watchdog_info sama5d4_wdt_info = {
.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
.identity = "Atmel SAMA5D4 Watchdog",
};
static const struct watchdog_ops sama5d4_wdt_ops = {
.owner = THIS_MODULE,
- .start = sama5d4_wdt_start,
- .stop = sama5d4_wdt_stop,
- .ping = sama5d4_wdt_ping,
- .set_timeout = sama5d4_wdt_set_timeout,
+ .start = wdt_start,
+ .stop = wdt_stop,
+ .ping = wdt_ping,
+ .set_timeout = wdt_set_timeout,
};
-static irqreturn_t sama5d4_wdt_irq_handler(int irq, void *dev_id)
+static irqreturn_t wdt_irq_handler(int irq, void *dev_id)
{
struct sama5d4_wdt *wdt = platform_get_drvdata(dev_id);
u32 reg;
- if (wdt->sam9x60_support)
- reg = wdt_read(wdt, AT91_SAM9X60_ISR);
+ if (wdt->is_modern_chip)
+ reg = wdt_read(wdt, AT91_WDT_ISR);
else
reg = wdt_read(wdt, AT91_WDT_SR);
if (reg) {
pr_crit("Atmel Watchdog Software Reset\n");
emergency_restart();
pr_crit("Reboot didn't succeed\n");
}
return IRQ_HANDLED;
}
-static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt)
+static int of_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt)
{
const char *tmp;
- if (wdt->sam9x60_support)
- wdt->mr = AT91_SAM9X60_WDDIS;
- else
- wdt->mr = AT91_WDT_WDDIS;
+ wdt->mr = wdt->wddis_mask;
if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
!strcmp(tmp, "software"))
wdt->need_irq = true;
if (of_property_read_bool(np, "atmel,idle-halt"))
wdt->mr |= AT91_WDT_WDIDLEHLT;
if (of_property_read_bool(np, "atmel,dbg-halt"))
wdt->mr |= AT91_WDT_WDDBGHLT;
return 0;
}
-static int sama5d4_wdt_init(struct sama5d4_wdt *wdt)
+static int wdt_init(struct sama5d4_wdt *wdt)
{
+ struct watchdog_device *wdd = &wdt->wdd;
u32 reg, val;
val = WDT_SEC2TICKS(WDT_DEFAULT_TIMEOUT);
+
/*
* When booting and resuming, the bootloader may have changed the
* watchdog configuration.
- * If the watchdog is already running, we can safely update it.
- * Else, we have to disable it properly.
+ * If the watchdog is not running, we need to disable it properly.
+ * Otherwise, we can safely update it.
*/
- if (!wdt_enabled) {
- reg = wdt_read(wdt, AT91_WDT_MR);
- if (wdt->sam9x60_support && (!(reg & AT91_SAM9X60_WDDIS)))
- wdt_write_nosleep(wdt, AT91_WDT_MR,
- reg | AT91_SAM9X60_WDDIS);
- else if (!wdt->sam9x60_support &&
- (!(reg & AT91_WDT_WDDIS)))
- wdt_write_nosleep(wdt, AT91_WDT_MR,
- reg | AT91_WDT_WDDIS);
+ reg = wdt_read(wdt, AT91_WDT_MR);
+ if (wdt_enabled(wdt, reg)) {
+ wdt->mr &= ~wdt->wddis_mask;
+ set_bit(WDOG_HW_RUNNING, &wdd->status);
+ } else {
+ wdt->mr |= wdt->wddis_mask;
}
- if (wdt->sam9x60_support) {
+ if (wdt->is_modern_chip) {
if (wdt->need_irq)
- wdt->ir = AT91_SAM9X60_PERINT;
+ wdt->ir = AT91_WDT_PERINT;
else
- wdt->mr |= AT91_SAM9X60_PERIODRST;
+ wdt->mr |= AT91_WDT_PERIODRST;
- wdt_write(wdt, AT91_SAM9X60_IER, wdt->ir);
- wdt_write(wdt, AT91_SAM9X60_WLR, AT91_SAM9X60_SET_COUNTER(val));
+ wdt_write(wdt, AT91_WDT_IER, wdt->ir);
+ wdt_write(wdt, AT91_WDT_WLR, AT91_WDT_SET_COUNTER(val));
} else {
wdt->mr |= AT91_WDT_SET_WDD(WDT_SEC2TICKS(MAX_WDT_TIMEOUT));
wdt->mr |= AT91_WDT_SET_WDV(val);
if (wdt->need_irq)
wdt->mr |= AT91_WDT_WDFIEN;
else
wdt->mr |= AT91_WDT_WDRSTEN;
}
wdt_write_nosleep(wdt, AT91_WDT_MR, wdt->mr);
return 0;
}
-static int sama5d4_wdt_probe(struct platform_device *pdev)
+static int wdt_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct watchdog_device *wdd;
struct sama5d4_wdt *wdt;
void __iomem *regs;
u32 irq = 0;
- u32 reg;
int ret;
wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);
if (!wdt)
return -ENOMEM;
wdd = &wdt->wdd;
wdd->timeout = WDT_DEFAULT_TIMEOUT;
wdd->info = &sama5d4_wdt_info;
wdd->ops = &sama5d4_wdt_ops;
wdd->min_timeout = MIN_WDT_TIMEOUT;
wdd->max_timeout = MAX_WDT_TIMEOUT;
wdt->last_ping = jiffies;
-
- if (of_device_is_compatible(dev->of_node, "microchip,sam9x60-wdt") ||
- of_device_is_compatible(dev->of_node, "microchip,sama7g5-wdt"))
- wdt->sam9x60_support = true;
+ wdt->is_modern_chip = check_is_modern_chip_by_compatible(dev);
+ if (wdt->is_modern_chip)
+ wdt->wddis_mask = AT91_WDT_WDDIS_MODERN;
+ else
+ wdt->wddis_mask = AT91_WDT_WDDIS_LEGACY;
watchdog_set_drvdata(wdd, wdt);
regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(regs))
return PTR_ERR(regs);
wdt->reg_base = regs;
- ret = of_sama5d4_wdt_init(dev->of_node, wdt);
+ ret = of_wdt_init(dev->of_node, wdt);
if (ret)
return ret;
if (wdt->need_irq) {
irq = irq_of_parse_and_map(dev->of_node, 0);
if (!irq) {
dev_warn(dev, "failed to get IRQ from DT\n");
wdt->need_irq = false;
}
}
if (wdt->need_irq) {
- ret = devm_request_irq(dev, irq, sama5d4_wdt_irq_handler,
+ ret = devm_request_irq(dev, irq, wdt_irq_handler,
IRQF_SHARED | IRQF_IRQPOLL |
IRQF_NO_SUSPEND, pdev->name, pdev);
if (ret) {
dev_err(dev, "cannot register interrupt handler\n");
return ret;
}
}
watchdog_init_timeout(wdd, wdt_timeout, dev);
- reg = wdt_read(wdt, AT91_WDT_MR);
- if (!(reg & AT91_WDT_WDDIS)) {
- wdt->mr &= ~AT91_WDT_WDDIS;
- set_bit(WDOG_HW_RUNNING, &wdd->status);
- }
-
- ret = sama5d4_wdt_init(wdt);
+ ret = wdt_init(wdt);
if (ret)
return ret;
watchdog_set_nowayout(wdd, nowayout);
watchdog_stop_on_unregister(wdd);
ret = devm_watchdog_register_device(dev, wdd);
if (ret)
return ret;
platform_set_drvdata(pdev, wdt);
dev_info(dev, "initialized (timeout = %d sec, nowayout = %d)\n",
wdd->timeout, nowayout);
return 0;
}
-static const struct of_device_id sama5d4_wdt_of_match[] = {
+static const struct of_device_id wdt_of_match[] = {
{
.compatible = "atmel,sama5d4-wdt",
},
{
.compatible = "microchip,sam9x60-wdt",
},
{
.compatible = "microchip,sama7g5-wdt",
},
{ }
};
-MODULE_DEVICE_TABLE(of, sama5d4_wdt_of_match);
+MODULE_DEVICE_TABLE(of, wdt_of_match);
-static int sama5d4_wdt_suspend_late(struct device *dev)
+static int wdt_suspend_late(struct device *dev)
{
struct sama5d4_wdt *wdt = dev_get_drvdata(dev);
if (watchdog_active(&wdt->wdd))
- sama5d4_wdt_stop(&wdt->wdd);
+ wdt_stop(&wdt->wdd);
return 0;
}
-static int sama5d4_wdt_resume_early(struct device *dev)
+static int wdt_resume_early(struct device *dev)
{
struct sama5d4_wdt *wdt = dev_get_drvdata(dev);
/*
* FIXME: writing MR also pings the watchdog which may not be desired.
* This should only be done when the registers are lost on suspend but
* there is no way to get this information right now.
*/
- sama5d4_wdt_init(wdt);
+ wdt_init(wdt);
if (watchdog_active(&wdt->wdd))
- sama5d4_wdt_start(&wdt->wdd);
+ wdt_start(&wdt->wdd);
return 0;
}
static const struct dev_pm_ops sama5d4_wdt_pm_ops = {
- LATE_SYSTEM_SLEEP_PM_OPS(sama5d4_wdt_suspend_late,
- sama5d4_wdt_resume_early)
+ LATE_SYSTEM_SLEEP_PM_OPS(wdt_suspend_late,
+ wdt_resume_early)
};
static struct platform_driver sama5d4_wdt_driver = {
- .probe = sama5d4_wdt_probe,
+ .probe = wdt_probe,
.driver = {
.name = "sama5d4_wdt",
.pm = pm_sleep_ptr(&sama5d4_wdt_pm_ops),
- .of_match_table = sama5d4_wdt_of_match,
+ .of_match_table = wdt_of_match,
}
};
module_platform_driver(sama5d4_wdt_driver);
MODULE_AUTHOR("Atmel Corporation");
MODULE_DESCRIPTION("Atmel SAMA5D4 Watchdog Timer driver");
MODULE_LICENSE("GPL v2");
--
2.34.1
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