soc/amd/*: Make mtrr decision based on syscfg

The syscfg has to option to automatically mark the range between 4G and
TOM2, which contains DRAM, as WB. Making it generally not necessary to
allocate MTRRs for memory above 4G if no PCI BARs are placed up there.

Change-Id: Ifbacae28e272ab2f39f268ad034354a9c590d035
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64868
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>

src/soc/amd/cezanne/cpu.c

@@ -7,6 +7,7 @@
 #include <assert.h>
 #include <console/console.h>
 #include <cpu/amd/microcode.h>
+#include <cpu/amd/mtrr.h>
 #include <cpu/cpu.h>
 #include <cpu/x86/mp.h>
 #include <cpu/x86/mtrr.h>
@@ -31,7 +32,11 @@ _Static_assert(CONFIG_MAX_CPUS == 16, "Do not override MAX_CPUS. To reduce the n
  */
 static void pre_mp_init(void)
 {
-	x86_setup_mtrrs_with_detect_no_above_4gb();
+	const msr_t syscfg = rdmsr(SYSCFG_MSR);
+	if (syscfg.lo & SYSCFG_MSR_TOM2WB)
+		x86_setup_mtrrs_with_detect_no_above_4gb();
+	else
+		x86_setup_mtrrs_with_detect();
 	x86_mtrr_check();
 }
 

src/soc/amd/picasso/cpu.c

@@ -1,24 +1,25 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <acpi/acpi.h>
 #include <amdblocks/cpu.h>
 #include <amdblocks/mca.h>
 #include <amdblocks/reset.h>
 #include <amdblocks/smm.h>
 #include <assert.h>
-#include <cpu/cpu.h>
-#include <cpu/x86/mp.h>
-#include <cpu/x86/mtrr.h>
-#include <cpu/x86/msr.h>
-#include <cpu/x86/smm.h>
-#include <acpi/acpi.h>
-#include <device/device.h>
-#include <device/pci_ops.h>
-#include <soc/pci_devs.h>
-#include <soc/cpu.h>
-#include <soc/smi.h>
-#include <soc/iomap.h>
 #include <console/console.h>
 #include <cpu/amd/microcode.h>
+#include <cpu/amd/mtrr.h>
+#include <cpu/cpu.h>
+#include <cpu/x86/mp.h>
+#include <cpu/x86/msr.h>
+#include <cpu/x86/mtrr.h>
+#include <cpu/x86/smm.h>
+#include <device/device.h>
+#include <device/pci_ops.h>
+#include <soc/cpu.h>
+#include <soc/iomap.h>
+#include <soc/pci_devs.h>
+#include <soc/smi.h>
 #include <types.h>
 
 _Static_assert(CONFIG_MAX_CPUS == 8, "Do not override MAX_CPUS. To reduce the number of "
@@ -35,7 +36,11 @@ _Static_assert(CONFIG_MAX_CPUS == 8, "Do not override MAX_CPUS. To reduce the nu
  */
 static void pre_mp_init(void)
 {
-	x86_setup_mtrrs_with_detect_no_above_4gb();
+	const msr_t syscfg = rdmsr(SYSCFG_MSR);
+	if (syscfg.lo & SYSCFG_MSR_TOM2WB)
+		x86_setup_mtrrs_with_detect_no_above_4gb();
+	else
+		x86_setup_mtrrs_with_detect();
 	x86_mtrr_check();
 }
 

src/soc/amd/sabrina/cpu.c

@@ -9,6 +9,7 @@
 #include <assert.h>
 #include <console/console.h>
 #include <cpu/amd/microcode.h>
+#include <cpu/amd/mtrr.h>
 #include <cpu/cpu.h>
 #include <cpu/x86/mp.h>
 #include <cpu/x86/mtrr.h>
@@ -33,7 +34,11 @@ _Static_assert(CONFIG_MAX_CPUS == 8, "Do not override MAX_CPUS. To reduce the nu
  */
 static void pre_mp_init(void)
 {
-	x86_setup_mtrrs_with_detect_no_above_4gb();
+	const msr_t syscfg = rdmsr(SYSCFG_MSR);
+	if (syscfg.lo & SYSCFG_MSR_TOM2WB)
+		x86_setup_mtrrs_with_detect_no_above_4gb();
+	else
+		x86_setup_mtrrs_with_detect();
 	x86_mtrr_check();
 }
 

src/soc/amd/stoneyridge/cpu.c

@@ -3,20 +3,21 @@
 #include <amdblocks/mca.h>
 #include <amdblocks/reset.h>
 #include <amdblocks/smm.h>
+#include <console/console.h>
 #include <cpu/amd/msr.h>
+#include <cpu/amd/mtrr.h>
 #include <cpu/cpu.h>
 #include <cpu/x86/mp.h>
-#include <cpu/x86/mtrr.h>
 #include <cpu/x86/msr.h>
+#include <cpu/x86/mtrr.h>
 #include <cpu/x86/smm.h>
 #include <device/device.h>
 #include <device/pci_ops.h>
-#include <soc/pci_devs.h>
 #include <soc/cpu.h>
-#include <soc/northbridge.h>
-#include <soc/smi.h>
 #include <soc/iomap.h>
-#include <console/console.h>
+#include <soc/northbridge.h>
+#include <soc/pci_devs.h>
+#include <soc/smi.h>
 #include <types.h>
 
 /*
@@ -32,7 +33,11 @@
  */
 static void pre_mp_init(void)
 {
-	x86_setup_mtrrs_with_detect();
+	const msr_t syscfg = rdmsr(SYSCFG_MSR);
+	if (syscfg.lo & SYSCFG_MSR_TOM2WB)
+		x86_setup_mtrrs_with_detect_no_above_4gb();
+	else
+		x86_setup_mtrrs_with_detect();
 	x86_mtrr_check();
 }