github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-09-22 04:34:03 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

watchdog: take all OF aliases into account when assigning id

Browse Source 
If some, but not all, watchdog devices have device tree aliases, those
without aliases might (depending on probe order) be assigned an id
which would otherwise be assigned to one of those with an alias.

This is problematic when for example watchdog0 is an alias for an
always-running gpio watchdog that userspace must handle, but the SOC's
watchdog device(s) get probed first and thus one of those become
/dev/watchdog0, and then at some point later, the gpio watchdog device
gets probed and becomes /dev/watchdog5.

Ensure that ids for devices without a device tree alias are allocated
from among those where no watchdogX alias exists.

Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20260714105356.2931450-1-linux@rasmusvillemoes.dk
[groeck: Use scnprintf() instead of snprintf() to make gcc happy]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Rasmus Villemoes 2026-07-14 12:53:56 +02:00 committed by Guenter Roeck
parent 5e845fe634
commit 19ff50d05f
1 changed files with 23 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
drivers/watchdog/watchdog_core.c
View File

@ -240,7 +240,9 @@ EXPORT_SYMBOL_GPL(watchdog_set_restart_priority);
static int ___watchdog_register_device(struct watchdog_device *wdd)
{
int ret, id = -1;
int ret, min_id, id = -1;
struct device_node *np;
char alias[16];
if (wdd == NULL || wdd->info == NULL || wdd->ops == NULL)
return -EINVAL;
@ -265,8 +267,26 @@ static int ___watchdog_register_device(struct watchdog_device *wdd)
GFP_KERNEL);
}
if (id < 0)
id = ida_alloc_max(&watchdog_ida, MAX_DOGS - 1, GFP_KERNEL);
/*
* Find an id which is not pre-assigned via a DT alias to some
* other, possibly not yet probed, watchdog device.
*/
if (id < 0) {
np = of_find_node_by_path("/aliases");
for (min_id = 0; ; min_id = id + 1) {
id = ida_alloc_range(&watchdog_ida, min_id, MAX_DOGS - 1,
GFP_KERNEL);
if (!np || id < 0)
break;
scnprintf(alias, sizeof(alias), "watchdog%d", id);
if (!of_get_property(np, alias, NULL))
break;
ida_free(&watchdog_ida, id);
}
of_node_put(np);
}
if (id < 0)
return id;