soc/amd/stoneyridge: add and use mca_is_valid_bank & mca_get_bank_name

This patch changes the way how the not implemented MCA bank 3 gets
skipped. For the not implemented bank 3 the name gets set to NULL
resulting in mca_is_valid_bank returning false causing the bank to get
skipped. This is a preparation for commonizing the MCA(X) handing in the
soc/amd sub-tree.

Change-Id: I40d6a6752504d804c45b445fce7e763e80161211
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56277
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>

1 files changed, 18 insertions, 3 deletions

diff --git a/src/soc/amd/stoneyridge/mca.c b/src/soc/amd/stoneyridge/mca.c
index 50e7fdd6f3..bdb06ccfa2 100644
--- a/src/soc/amd/stoneyridge/mca.c
+++ b/src/soc/amd/stoneyridge/mca.c
@@ -139,18 +139,33 @@ static const char *const mca_bank_name[] = {
 	[0] = "Load-store unit",
 	[1] = "Instruction fetch unit",
 	[2] = "Combined unit",
-	[3] = "Reserved",
+	/* Bank 3 is reserved and not all corresponding MSRs are implemented in Family 15h.
+	   Accessing non-existing MSRs causes a general protection fault. */
+	[3] = NULL,
 	[4] = "Northbridge",
 	[5] = "Execution unit",
 	[6] = "Floating point unit"
 };
 
+static bool mca_is_valid_bank(unsigned int bank)
+{
+	return (bank < ARRAY_SIZE(mca_bank_name) && mca_bank_name[bank] != NULL);
+}
+
+static const char *mca_get_bank_name(unsigned int bank)
+{
+	if (mca_is_valid_bank(bank))
+		return mca_bank_name[bank];
+	else
+		return "";
+}
+
 static void mca_print_error(unsigned int bank)
 {
 	msr_t msr;
 
 	printk(BIOS_WARNING, "#MC Error: core %u, bank %u %s\n", initial_lapicid(), bank,
-		mca_bank_name[bank]);
+		mca_get_bank_name(bank));
 
 	msr = rdmsr(IA32_MC_STATUS(bank));
 	printk(BIOS_WARNING, "   MC%u_STATUS =   %08x_%08x\n", bank, msr.hi, msr.lo);
@@ -173,7 +188,7 @@ static void mca_check_all_banks(void)
 		return;
 
 	for (unsigned int i = 0 ; i < num_banks ; i++) {
-		if (i == 3) /* Reserved in Family 15h */
+		if (!mca_is_valid_bank(i))
 			continue;
 
 		mci.bank = i;