clear wakeup enable bit upon resuming from suspend
The FVP specific code that gets called after a cpu has been physically
powered on after having been turned off or suspended earlier does not
clear the PWRC.PWKUPR.WEN bit. Not doing so causes problems if: a cpu
is suspended, woken from suspend, powered down through a cpu_off call
& receives a spurious interrupt. Since the WEN bit is not cleared
after the cpu woke up from suspend, the spurious wakeup will power the
cpu on. Since the cpu_off call clears the jump address in the mailbox
this spurious wakeup will cause the cpu to crash.
This patch fixes this issue by clearing the WEN bit whenever a cpu is
powered up.
Change-Id: Ic91f5dffe1ed01d76bc7fc807acf0ecd3e38ce5b
diff --git a/plat/fvp/fvp_pm.c b/plat/fvp/fvp_pm.c
index fd92526..658a285 100644
--- a/plat/fvp/fvp_pm.c
+++ b/plat/fvp/fvp_pm.c
@@ -251,7 +251,7 @@
* Program the power controller to power this
* cpu off and enable wakeup interrupts.
*/
- fvp_pwrc_write_pwkupr(mpidr);
+ fvp_pwrc_set_wen(mpidr);
fvp_pwrc_write_ppoffr(mpidr);
}
break;
@@ -309,6 +309,12 @@
write_cpuectlr(ectlr);
}
+ /*
+ * Clear PWKUPR.WEN bit to ensure interrupts do not interfere
+ * with a cpu power down unless the bit is set again
+ */
+ fvp_pwrc_clr_wen(mpidr);
+
/* Zero the jump address in the mailbox for this cpu */
fvp_mboxes = (mailbox *) (TZDRAM_BASE + MBOX_OFF);
linear_id = platform_get_core_pos(mpidr);