[PATCH v4 07/10] watchdog: wdt-uclass.c: handle all DM watchdogs in watchdog_reset()

Rasmus Villemoes
2021-08-02T15:02:22Z

A board can have and make use of more than one watchdog device, say
one built into the SOC and an external gpio-petted one. Having
wdt-uclass only handle the first is both a little arbitrary and
unexpected.

So change initr_watchdog() so we visit (probe) all DM watchdog
devices, and call the init_watchdog_dev helper for each.

Similarly let watchdog_reset() loop over the whole uclass - each
having their own ratelimiting metadata, and a separate "is this device
running" flag.

This gets rid of the watchdog_dev member of struct global_data. We
do, however, still need the GD_FLG_WDT_READY set in
initr_watchdog(). This is because watchdog_reset() can get called
before DM is ready, and I don't think we can call uclass_get() that
early.

The current code just returns 0 if "getting" the first device fails -
that can of course happen because there are no devices, but it could
also happen if its ->probe call failed. In keeping with that, continue
with the handling of the remaining devices even if one fails to
probe. This is also why we cannot use uclass_probe_all().

If desired, it's possible to later add a per-device "u-boot,autostart"
boolean property, so that one can do CONFIG_WATCHDOG_AUTOSTART
per-device.

Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
---
drivers/watchdog/wdt-uclass.c | 56 ++++++++++++++++++++-----------
include/asm-generic/global_data.h | 6 ----
2 files changed, 36 insertions(+), 26 deletions(-)

diff --git a/drivers/watchdog/wdt-uclass.c b/drivers/watchdog/wdt-uclass.c
index 358fc68e27..0ce8b3a425 100644
--- a/drivers/watchdog/wdt-uclass.c
+++ b/drivers/watchdog/wdt-uclass.c
@@ -61,20 +61,24 @@ static void init_watchdog_dev(struct udevice *dev)

int initr_watchdog(void)
{
- /*
- * Init watchdog: This will call the probe function of the
- * watchdog driver, enabling the use of the device
- */
- if (uclass_get_device_by_seq(UCLASS_WDT, 0,
- (struct udevice **)&gd->watchdog_dev)) {
- debug("WDT: Not found by seq!\n");
- if (uclass_get_device(UCLASS_WDT, 0,
- (struct udevice **)&gd->watchdog_dev)) {
- printf("WDT: Not found!\n");
- return 0;
+ struct udevice *dev;
+ struct uclass *uc;
+ int ret;
+
+ ret = uclass_get(UCLASS_WDT, &uc);
+ if (ret) {
+ log_debug("Error getting UCLASS_WDT: %d\n", ret);
+ return 0;
+ }
+
+ uclass_foreach_dev(dev, uc) {
+ ret = device_probe(dev);
+ if (ret) {
+ log_debug("Error probing %s: %d\n", dev->name, ret);
+ continue;
}
+ init_watchdog_dev(dev);
}
- init_watchdog_dev(gd->watchdog_dev);

gd->flags |= GD_FLG_WDT_READY;
return 0;
@@ -157,22 +161,34 @@ void watchdog_reset(void)
{
struct wdt_priv *priv;
struct udevice *dev;
+ struct uclass *uc;
ulong now;

/* Exit if GD is not ready or watchdog is not initialized yet */
if (!gd || !(gd->flags & GD_FLG_WDT_READY))
return;

- dev = gd->watchdog_dev;
- priv = dev_get_uclass_priv(dev);
- if (!priv->running)
+ if (uclass_get(UCLASS_WDT, &uc))
return;

- /* Do not reset the watchdog too often */
- now = get_timer(0);
- if (time_after_eq(now, priv->next_reset)) {
- priv->next_reset = now + priv->reset_period;
- wdt_reset(dev);
+ /*
+ * All devices bound to the wdt uclass should have been probed
+ * in initr_watchdog(). But just in case something went wrong,
+ * check device_active() before accessing the uclass private
+ * data.
+ */
+ uclass_foreach_dev(dev, uc) {
+ if (!device_active(dev))
+ continue;
+ priv = dev_get_uclass_priv(dev);
+ if (!priv->running)
+ continue;
+ /* Do not reset the watchdog too often */
+ now = get_timer(0);
+ if (time_after_eq(now, priv->next_reset)) {
+ priv->next_reset = now + priv->reset_period;
+ wdt_reset(dev);
+ }
}
}
#endif
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index e55070303f..28d749538c 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -447,12 +447,6 @@ struct global_data {
*/
fdt_addr_t translation_offset;
#endif
-#if CONFIG_IS_ENABLED(WDT)
- /**
- * @watchdog_dev: watchdog device
- */
- struct udevice *watchdog_dev;
-#endif
#ifdef CONFIG_GENERATE_ACPI_TABLE
/**
* @acpi_ctx: ACPI context pointer
--
2.31.1