Re: [PATCH] BCM2711 reboot fix

["Evgeny Beysembaev" <evgeny@xxxxxxxxxxxxxxxx>]

According to the commit b334c1afad17 ("ARM: dts: bcm2711: Use proper compatible in PM/Watchdog node")
in Linux kernel, the `compatible` string for the watchdog peripheral in the DTS has been modified from
`brcm,bcm2835-pm` to `brcm,bcm2711-pm`, which caused `rpi4_map_watchdog()` function to fail,
leading to inability to reboot the system under Xen hypervisor.

Signed-off-by: Evgeny Beysembaev <evgeny@xxxxxxxxxxxxxxxx>
---
xen/arch/arm/platforms/brcm-raspberry-pi.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/xen/arch/arm/platforms/brcm-raspberry-pi.c b/xen/arch/arm/platforms/brcm-raspberry-pi.c
index 811b40b1a6..74fca7ecc5 100644
--- a/xen/arch/arm/platforms/brcm-raspberry-pi.c
+++ b/xen/arch/arm/platforms/brcm-raspberry-pi.c
@@ -60,9 +60,12 @@ static void __iomem *rpi4_map_watchdog(void)
    paddr_t start, len;
    int ret;

-    node = dt_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm");
-    if ( !node )
-        return NULL;
+    node = dt_find_compatible_node(NULL, NULL, "brcm,bcm2711-pm");
+    if ( !node ) {
+        node = dt_find_compatible_node(NULL, NULL, "brcm,bcm2835-pm");
+        if ( !node )
+            return NULL;
+    }

    ret = dt_device_get_address(node, 0, &start, &len);
    if ( ret )
--  
2.47.2

On Friday, May 30, 2025 at 11:40:23 pm +03:00, Julien Grall <julien@xxxxxxx> wrote:

Hi Evgeny,

Thank you for the patch. Let me start with the process,

patches are submitted inline rather than in attachment.

git-send-email commmand can do that for you.

Now regarding the patch. I understand that newer kernel

will use the new compatible. But I would assume there is

still some device-tree out using the old property. So I

think Xen needs to check both compatible.

Lastly, for the future,when mentioning we commit, we tend to use a smaller

hash (12 digits) followed by the commit title. In your case,

it would be:

b334c1afad17 ("ARM: dts: bcm2711: Use proper compatible in PM/Watchdog node").

Cheers,

--

Julien Grall