qemu: Implement PSCI_CPU_OFF.
This is based on the rpi implementation from
https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/2746.
Signed-off-by: Andrew Walbran <qwandor@google.com>
Change-Id: I5fe324fcd9d5e232091e01267ea12147c46bc9c1
diff --git a/plat/qemu/common/aarch64/plat_helpers.S b/plat/qemu/common/aarch64/plat_helpers.S
index 13a5ee4..dbcdc2d 100644
--- a/plat/qemu/common/aarch64/plat_helpers.S
+++ b/plat/qemu/common/aarch64/plat_helpers.S
@@ -70,6 +70,12 @@
poll_mailbox:
ldr x1, [x2, x0]
cbz x1, 1f
+
+ /* Clear the mailbox again ready for next time. */
+ mov x1, #PLAT_QEMU_HOLD_STATE_WAIT
+ str x1, [x2, x0]
+
+ /* Jump to the provided entrypoint. */
mov_imm x0, PLAT_QEMU_TRUSTED_MAILBOX_BASE
ldr x1, [x0]
br x1