[Skiboot] [PATCH] mbox: Sanitize interrupts registers

[Benjamin Herrenschmidt]

If some status interrupts are left unmasked by a previous
firmware run (either HostBoot or some other version of skiboot),
we fail to clear them and end up with a runaway SerIRQ.

Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
---

Let's merge that now. It will be obsoleted by the v2 protocol
implementation but we want a fix out ASAP.

 hw/lpc-mbox.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/hw/lpc-mbox.c b/hw/lpc-mbox.c
index fd107fb..21e6eee 100644
--- a/hw/lpc-mbox.c
+++ b/hw/lpc-mbox.c
@@ -200,11 +200,18 @@ static struct lpc_client mbox_lpc_client = {
 
 static bool mbox_init_hw(void)
 {
-	/*
-	 * Turns out there isn't anything to do.
-	 * It might be a good idea to santise the registers though.
-	 * TODO
+	/* Disable all status interrupts except attentions */
+	bmc_mbox_outb(0x00, MBOX_HOST_INT_EN_0);
+	bmc_mbox_outb(MBOX_STATUS_ATTN, MBOX_HOST_INT_EN_1);
+
+	/* Cleanup host interrupt and status */
+	bmc_mbox_outb(MBOX_CTRL_INT_STATUS, MBOX_HOST_CTRL);
+
+	/* Disable host control interrupt for now (will be
+	 * re-enabled when needed). Clear BMC interrupts
 	 */
+	bmc_mbox_outb(MBOX_CTRL_INT_MASK, MBOX_BMC_CTRL);
+
 	return true;
 }