soc/amd/common/block/cpu/tsc/tsc_freq: use get_pstate_core_freq

Use get_pstate_core_freq instead of open-coding the calculations in
tsc_freq_mhz. In the case of the CPU frequency divider being 0,
get_pstate_core_freq will return 0; in this case that shouldn't happen,
TSC_DEFAULT_FREQ_MHZ will be used as frequency, since for the TSC
frequency it's better to err on the end of the expected frequency being
too high which will cause longer than expected delays instead of too
short delays.

Now that the code is using get_pstate_core_freq, this code is valid for
Glinda too, so also remove the comment on the
SOC_AMD_COMMON_BLOCK_TSC_FAM17H_19H option being selected in the Glinda
Kconfig. This Kconfig option will be renamed in a follow-up patch.

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I01168834d4018c92f44782eda0c65b1aa392030d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74013
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Martin Roth <martin.roth@amd.corp-partner.google.com>

2 files changed, 8 insertions, 15 deletions

diff --git a/src/soc/amd/common/block/cpu/tsc/tsc_freq.c b/src/soc/amd/common/block/cpu/tsc/tsc_freq.c
index fbbf399731..f177b77673 100644
--- a/src/soc/amd/common/block/cpu/tsc/tsc_freq.c
+++ b/src/soc/amd/common/block/cpu/tsc/tsc_freq.c
@@ -1,9 +1,11 @@
 /* SPDX-License-Identifier: GPL-2.0-or-later */
 
+#include <amdblocks/cpu.h>
 #include <cpu/x86/msr.h>
 #include <cpu/amd/msr.h>
 #include <cpu/x86/tsc.h>
 #include <console/console.h>
+#include <soc/msr.h>
 
 static unsigned long mhz;
 
@@ -13,31 +15,22 @@ static unsigned long mhz;
 
 unsigned long tsc_freq_mhz(void)
 {
-	msr_t msr;
-	uint8_t cpufid;
-	uint8_t cpudid;
+	union pstate_msr pstate_reg;
 	uint8_t high_state;
 
 	if (mhz)
 		return mhz;
 
 	high_state = rdmsr(PS_LIM_REG).lo & 0x7;
-	msr = rdmsr(PSTATE_MSR(high_state));
-	if (!(msr.hi & 0x80000000))
+	pstate_reg.raw = rdmsr(PSTATE_MSR(high_state)).raw;
+	if (!pstate_reg.pstate_en)
 		die("Unknown error: cannot determine P-state 0\n");
 
-	cpufid = (msr.lo & 0xff);
-	cpudid = (msr.lo & 0x3f00) >> 8;
+	mhz = get_pstate_core_freq(pstate_reg);
 
-	/* normally core frequency is calculated as (fid * 25) / (did / 8) */
-	if (!cpudid) {
+	if (!mhz) {
 		mhz = TSC_DEFAULT_FREQ_MHZ;
 		printk(BIOS_ERR, "Invalid divisor, set TSC frequency to %ldMHz\n", mhz);
-	} else if ((cpudid >= 8) && (cpudid <= 0x30)) {
-		mhz = (200 * cpufid) / cpudid;
-	} else {
-		mhz = 25 * cpufid;
-		printk(BIOS_ERR, "Invalid frequency divisor 0x%x, assume 1\n", cpudid);
 	}
 
 	return mhz;
diff --git a/src/soc/amd/glinda/Kconfig b/src/soc/amd/glinda/Kconfig
index c68ee47b00..ac46395480 100644
--- a/src/soc/amd/glinda/Kconfig
+++ b/src/soc/amd/glinda/Kconfig
@@ -71,7 +71,7 @@ config SOC_AMD_GLINDA
 	select SOC_AMD_COMMON_BLOCK_SMU_SX_ENTRY	# TODO: Check if this is still correct
 	select SOC_AMD_COMMON_BLOCK_SPI			# TODO: Check if this is still correct
 	select SOC_AMD_COMMON_BLOCK_SVI3
-	select SOC_AMD_COMMON_BLOCK_TSC_FAM17H_19H	# FIXME: This is likely incompatible
+	select SOC_AMD_COMMON_BLOCK_TSC_FAM17H_19H
 	select SOC_AMD_COMMON_BLOCK_UART		# TODO: Check if this is still correct
 	select SOC_AMD_COMMON_BLOCK_UCODE		# TODO: Check if this is still correct
 	select SOC_AMD_COMMON_FSP_CCX_CPPC_HOB		# TODO: Check if this is still correct