From 0889c3401c4b2c2c9359fdfe06a7169f8b9b4bc4 Mon Sep 17 00:00:00 2001
From: Vladimir 'phcoder' Serbinenko <phcoder@gmail.com>
Date: Sun, 23 Jan 2011 21:56:00 +0100
Subject: [PATCH] Explicitly enable MSR mailbox

---
 grub-core/boot/mips/yeeloong/fwstart.S | 4 ++++
 include/grub/cs5536.h                  | 8 +++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/grub-core/boot/mips/yeeloong/fwstart.S b/grub-core/boot/mips/yeeloong/fwstart.S
index 144c76ac6..184aff5d2 100644
--- a/grub-core/boot/mips/yeeloong/fwstart.S
+++ b/grub-core/boot/mips/yeeloong/fwstart.S
@@ -66,6 +66,10 @@ retry_cs5536:
 	 move $a0, $t4
 
 	/* Initialise SMBus controller.  */
+	lui $t0, %hi(GRUB_MACHINE_PCI_CONFSPACE)
+	li  $t1, GRUB_CS5536_MSR_MAILBOX_CONFIG_ENABLED
+	sw  $t1, (%lo(GRUB_MACHINE_PCI_CONFSPACE) + GRUB_CS5536_MSR_MAILBOX_CONFIG) ($t0)
+	
 	/* Set GPIO LBAR.  */
 	lui $a0, %hi(GRUB_CS5536_MSR_GPIO_BAR)
 	addiu $a0, $a0, %lo(GRUB_CS5536_MSR_GPIO_BAR)
diff --git a/include/grub/cs5536.h b/include/grub/cs5536.h
index cd17e11fc..de0d6df7e 100644
--- a/include/grub/cs5536.h
+++ b/include/grub/cs5536.h
@@ -26,9 +26,11 @@
 #endif
 
 #define GRUB_CS5536_PCIID 0x208f1022
-#define GRUB_CS5536_MSR_MAILBOX_ADDR  0xf4
-#define GRUB_CS5536_MSR_MAILBOX_DATA0 0xf8
-#define GRUB_CS5536_MSR_MAILBOX_DATA1 0xfc
+#define GRUB_CS5536_MSR_MAILBOX_CONFIG_ENABLED        0x1
+#define GRUB_CS5536_MSR_MAILBOX_CONFIG 0xf0
+#define GRUB_CS5536_MSR_MAILBOX_ADDR   0xf4
+#define GRUB_CS5536_MSR_MAILBOX_DATA0  0xf8
+#define GRUB_CS5536_MSR_MAILBOX_DATA1  0xfc
 #define GRUB_CS5536_MSR_IRQ_MAP_BAR 0x80000008
 #define GRUB_CS5536_MSR_SMB_BAR 0x8000000b