nvidia southbridges: don't touch 0x78 in LPC bridge with Fam10h

Based on the observations that AMD Fam10h with both Nvidia CK804 (Asus
KFSN4-DRE) and MCP55 (Sun Ultra 40 M2) need to avoid adjusting the LPC
bridge register 0x78 (particularly the 0x7b byte) to get to ramstage:
Assume that there's something about this register that adjusting it the
way we do for K8 is something that can/should be universally avoided on
all Fam10h systems with these chipsets.

Change-Id: I1eceeb20ecaefef4c61c11e19d1f5a59f91a0a2f
Signed-off-by: Jonathan A. Kollasch <jakllsch@kollasch.net>
Reviewed-on: http://review.coreboot.org/10984
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: Timothy Pearson <tpearson@raptorengineeringinc.com>

4 files changed, 37 insertions, 10 deletions

diff --git a/src/mainboard/asus/kfsn4-dre/romstage.c b/src/mainboard/asus/kfsn4-dre/romstage.c
index aa72021d8d..cf36a7265c 100644
--- a/src/mainboard/asus/kfsn4-dre/romstage.c
+++ b/src/mainboard/asus/kfsn4-dre/romstage.c
@@ -67,15 +67,6 @@ static inline int spd_read_byte(unsigned device, unsigned address)
 #include "resourcemap.c"
 #include "cpu/amd/quadcore/quadcore.c"
 
-/*
- * Avoid crash (complete with severe memory corruption!) during initial CAR boot
- * in ck804_early_setup_x().
- * Interestingly once the system is fully booted into Linux this can be set, but
- * not before!  Apparently something isn't initialized but the amount of effort
- * required to fix this is non-negligible and of unknown real-world benefit
- */
-#define CK804_SKIP_PCI_REG_78_INIT 1
-
 #define CK804_MB_SETUP \
 	RES_PORT_IO_8, SYSCTRL_IO_BASE + 0xc0+33, ~(0x0f),(0x04 | 0x01),	/* -ENOINFO Proprietary BIOS sets this register; "When in Rome..."*/
 
diff --git a/src/southbridge/nvidia/ck804/early_setup.c b/src/southbridge/nvidia/ck804/early_setup.c
index c0a8766ea5..9c0a7833e9 100644
--- a/src/southbridge/nvidia/ck804/early_setup.c
+++ b/src/southbridge/nvidia/ck804/early_setup.c
@@ -152,10 +152,24 @@ static void ck804_early_setup(void)
 	RES_PCI_IO, PCI_ADDR(CK804B_BUSN, CK804B_DEVN_BASE + 9, 0, 0x74), 0xffffffc0, 0x00000000,
 #endif
 
+#if IS_ENABLED(CONFIG_NORTHBRIDGE_AMD_AMDFAM10)
+	/*
+	 * Avoid crash (complete with severe memory corruption!) during initial CAR boot
+	 * in ck804_early_setup_x() on Fam10h systems by not touching 0x78.
+	 * Interestingly once the system is fully booted into Linux this can be set, but
+	 * not before!  Apparently something isn't initialized but the amount of effort
+	 * required to fix this is non-negligible and of unknown real-world benefit
+	 */
+#else
 	RES_PCI_IO, PCI_ADDR(0, CK804_DEVN_BASE + 1, 0, 0x78), 0xc0ffffff, 0x19000000,
+#endif
 	RES_PCI_IO, PCI_ADDR(0, CK804_DEVN_BASE + 1, 0, 0xe0), 0xfffffeff, 0x00000100,
 
 #if CONFIG_CK804_NUM > 1
+	/*
+	 * Avoid touching 0x78 for CONFIG_NORTHBRIDGE_AMD_AMDFAM10 for
+	 * non-primary chain too???
+	 */
 	RES_PCI_IO, PCI_ADDR(CK804B_BUSN, CK804B_DEVN_BASE + 1, 0, 0x78), 0xc0ffffff, 0x20000000,
 	RES_PCI_IO, PCI_ADDR(CK804B_BUSN, CK804B_DEVN_BASE + 1, 0, 0xe0), 0xfffffeff, 0x00000000,
 	RES_PCI_IO, PCI_ADDR(CK804B_BUSN, CK804B_DEVN_BASE + 1, 0, 0xe8), 0xffffff00, 0x000000ff,
diff --git a/src/southbridge/nvidia/ck804/early_setup_car.c b/src/southbridge/nvidia/ck804/early_setup_car.c
index 8065d20fdb..87fdbdd4d6 100644
--- a/src/southbridge/nvidia/ck804/early_setup_car.c
+++ b/src/southbridge/nvidia/ck804/early_setup_car.c
@@ -142,7 +142,15 @@ static void ck804_early_setup(unsigned ck804_num, unsigned *busn,
 		CK804_MB_SETUP
 #endif
 
-#ifndef CK804_SKIP_PCI_REG_78_INIT
+#if IS_ENABLED(CONFIG_NORTHBRIDGE_AMD_AMDFAM10)
+		/*
+		 * Avoid crash (complete with severe memory corruption!) during initial CAR boot
+		 * in ck804_early_setup_x() on Fam10h systems by not touching 0x78.
+		 * Interestingly once the system is fully booted into Linux this can be set, but
+		 * not before!  Apparently something isn't initialized but the amount of effort
+		 * required to fix this is non-negligible and of unknown real-world benefit
+		 */
+#else
 		RES_PCI_IO, PCI_ADDR(0, 1, 0, 0x78), 0xc0ffffff, 0x19000000,
 #endif
 		RES_PCI_IO, PCI_ADDR(0, 1, 0, 0xe0), 0xfffffeff, 0x00000100,
@@ -239,6 +247,10 @@ static void ck804_early_setup(unsigned ck804_num, unsigned *busn,
 		RES_PCI_IO, PCI_ADDR(0, 9, 0, 0x4c), 0xfe00ffff, 0x00440000,
 		RES_PCI_IO, PCI_ADDR(0, 9, 0, 0x74), 0xffffffc0, 0x00000000,
 
+		/*
+		 * Avoid touching 0x78 for CONFIG_NORTHBRIDGE_AMD_AMDFAM10 for
+		 * non-primary chains too???
+		 */
 		RES_PCI_IO, PCI_ADDR(0, 1, 0, 0x78), 0xc0ffffff, 0x20000000,
 		RES_PCI_IO, PCI_ADDR(0, 1, 0, 0xe0), 0xfffffeff, 0x00000000,
 		RES_PCI_IO, PCI_ADDR(0, 1, 0, 0xe8), 0xffffff00, 0x000000ff,
diff --git a/src/southbridge/nvidia/mcp55/early_setup_car.c b/src/southbridge/nvidia/mcp55/early_setup_car.c
index 4970a4cf9a..d919610900 100644
--- a/src/southbridge/nvidia/mcp55/early_setup_car.c
+++ b/src/southbridge/nvidia/mcp55/early_setup_car.c
@@ -242,7 +242,17 @@ static void mcp55_early_setup(unsigned mcp55_num, unsigned *busn,
 	RES_PCI_IO, PCI_ADDR(0, 6, 0, 0x74), 0xFFFFFFC0, 0x00000000,
 	RES_PCI_IO, PCI_ADDR(0, 6, 0, 0xC0), 0x00000000, 0xCB8410DE,
 	RES_PCI_IO, PCI_ADDR(0, 6, 0, 0xC4), 0xFFFFFFF8, 0x00000007,
+#if IS_ENABLED(CONFIG_NORTHBRIDGE_AMD_AMDFAM10)
+	/*
+	 * Avoid crash (complete with severe memory corruption!) during initial CAR boot
+	 * in mcp55_early_setup_x() on Fam10h systems by not touching 0x78.
+	 * Interestingly once the system is fully booted into Linux this can be set, but
+	 * not before!  Apparently something isn't initialized but the amount of effort
+	 * required to fix this is non-negligible and of unknown real-world benefit
+	 */
+#else
 	RES_PCI_IO, PCI_ADDR(0, 1, 0, 0x78), 0xC0FFFFFF, 0x19000000,
+#endif
 
 #if CONFIG_MCP55_USE_AZA
 	RES_PCI_IO, PCI_ADDR(0, 6, 1, 0x40), 0x00000000, 0xCB8410DE,