[PATCH v4 3/3] powerpc: dts: turris1x.dts: Set lower priority for CPLD syscon-reboot

From: Pali Rohár
Date: Mon Dec 26 2022 - 06:58:36 EST


Due to CPLD firmware bugs, set CPLD syscon-reboot priority level to 64
(between rstcr and watchdog) to ensure that rstcr's global-utilities reset
method which is preferred stay as default one, and to ensure that CPLD
syscon-reboot is more preferred than watchdog reset method.

Fixes: 0531a4abd1c6 ("powerpc: dts: turris1x.dts: Add CPLD reboot node")
Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
---
arch/powerpc/boot/dts/turris1x.dts | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

diff --git a/arch/powerpc/boot/dts/turris1x.dts b/arch/powerpc/boot/dts/turris1x.dts
index e9cda34a140e..c9b619f6ed5c 100644
--- a/arch/powerpc/boot/dts/turris1x.dts
+++ b/arch/powerpc/boot/dts/turris1x.dts
@@ -367,11 +367,34 @@
};

reboot@d {
+ /*
+ * CPLD firmware which manages system reset and
+ * watchdog registers has bugs. It does not
+ * autoclear system reset register after change
+ * and watchdog ignores reset line on immediate
+ * succeeding reset cycle triggered by watchdog.
+ * These bugs have to be workarounded in U-Boot
+ * bootloader. So use system reset via syscon as
+ * a last resort because older U-Boot versions
+ * do not have workaround for watchdog.
+ *
+ * Reset method via rstcr's global-utilities
+ * (the preferred one) has priority level 128,
+ * watchdog has priority level 0 and default
+ * syscon-reboot priority level is 192.
+ *
+ * So define syscon-reboot with custom priority
+ * level 64 (between rstcr and watchdog) because
+ * rstcr should stay as default preferred reset
+ * method and reset via watchdog is more broken
+ * than system reset via syscon.
+ */
compatible = "syscon-reboot";
reg = <0x0d 0x01>;
offset = <0x0d>;
mask = <0x01>;
value = <0x01>;
+ priority = <64>;
};

led-controller@13 {
--
2.20.1