[PATCH] bios: mtrr: print out actual default type of MTRR

[Ivan Hu]

Print out default type of MTRR instead of using "Most probably Uncached".
Also modify to get default type from MSR once, avoiding to get default type each
time we check cahch type.

Signed-off-by: Ivan Hu <ivan.hu at canonical.com>
---
 src/bios/mtrr/mtrr.c | 79 +++++++++++++++++++++++++++++++++-------------------
 1 file changed, 50 insertions(+), 29 deletions(-)

diff --git a/src/bios/mtrr/mtrr.c b/src/bios/mtrr/mtrr.c
index 7d29c2b..6386b6e 100644
--- a/src/bios/mtrr/mtrr.c
+++ b/src/bios/mtrr/mtrr.c
@@ -51,6 +51,8 @@ static fwts_cpuinfo_x86 *fwts_cpuinfo;
 
 #define MTRR_DEF_TYPE_MSR	0x2FF
 
+static	uint64_t mtrr_default;
+
 struct mtrr_entry {
 	uint8_t  reg;
 	uint64_t start;
@@ -74,8 +76,21 @@ static char *cache_to_string(int type)
 		strcat(str," Write-Through");
 	if (type & WRITE_PROTECT)
 		strcat(str," Write-Protect");
-	if (type & DEFAULT)
-		strcat(str," Default (Most probably Uncached)");
+	if (type & DEFAULT) {
+		strcat(str," Default");
+		if (mtrr_default & UNCACHED)
+			strcat(str," (Uncached)");
+		if (mtrr_default & WRITE_BACK)
+			strcat(str," (Write-Back)");
+		if (mtrr_default & WRITE_COMBINING)
+			strcat(str," (Write-Combining)");
+		if (mtrr_default & WRITE_THROUGH)
+			strcat(str," (Write-Through)");
+		if (mtrr_default & WRITE_PROTECT)
+			strcat(str," (Write-Protect)");
+		if (mtrr_default & UNKNOWN)
+			strcat(str," (Unknown)");
+	}
 	if (type & UNKNOWN)
 		strcat(str," Unknown");
 	return str;
@@ -167,12 +182,38 @@ static int get_mtrrs(void)
 	return FWTS_OK;
 }
 
+static int get_default_mtrr(void) {
+	if (fwts_cpu_readmsr(0, MTRR_DEF_TYPE_MSR, &mtrr_default) == FWTS_OK) {
+		switch (mtrr_default & 0xFF) {
+			case 0:
+				mtrr_default = UNCACHED;
+				break;
+			case 1:
+				mtrr_default = WRITE_COMBINING;
+				break;
+			case 4:
+				mtrr_default = WRITE_THROUGH;
+				break;
+			case 5:
+				mtrr_default = WRITE_PROTECT;
+				break;
+			case 6:
+				mtrr_default = WRITE_BACK;
+				break;
+			default:
+				mtrr_default = UNKNOWN;
+				break;
+		}
+		return FWTS_OK;
+	}
+	return FWTS_ERROR;
+}
+
 static int cache_types(uint64_t start, uint64_t end)
 {
 	fwts_list_link *item;
 	struct mtrr_entry *entry;
 	int type = 0;
-	uint64_t mtrr_default = UNCACHED;
 
 	fwts_list_foreach(item, mtrr_list) {
 		entry = fwts_list_data(struct mtrr_entry*, item);
@@ -202,32 +243,9 @@ restart:
 	if (start != end)
 		type |= DEFAULT;
 
-	if (fwts_cpu_readmsr(0, MTRR_DEF_TYPE_MSR, &mtrr_default) == FWTS_OK) {
-		switch (mtrr_default & 0xFF) {
-			case 0:
-				mtrr_default = UNCACHED;
-				break;
-			case 1:
-				mtrr_default = WRITE_COMBINING;
-				break;
-			case 4:
-				mtrr_default = WRITE_THROUGH;
-				break;
-			case 5:
-				mtrr_default = WRITE_PROTECT;
-				break;
-			case 6:
-				mtrr_default = WRITE_BACK;
-				break;
-			default:
-				mtrr_default = UNKNOWN;
-				break;
-		}
-
-		if ((type & DEFAULT) && mtrr_default != UNCACHED) {
-			type &= ~DEFAULT;
-			type |= mtrr_default;
-		}
+	if ((type & DEFAULT) && mtrr_default != UNCACHED) {
+		type &= ~DEFAULT;
+		type |= mtrr_default;
 	}
 
 	return type;
@@ -390,6 +408,9 @@ static int validate_iomem(fwts_framework *fw)
 	if ((file = fopen("/proc/iomem", "r")) == NULL)
 		return FWTS_ERROR;
 
+	if (get_default_mtrr() != FWTS_OK)
+		mtrr_default = UNKNOWN;
+
 	while (!feof(file)) {
 		uint64_t start;
 		uint64_t end;
-- 
2.7.4