Change in coreboot[master]: soc/intel/common/timer: Make TSC frequency calculation dynamically

[Patrick Georgi (Code Review)]

Patrick Georgi has submitted this change. ( https://review.coreboot.org/c/coreboot/+/35148 )

Change subject: soc/intel/common/timer: Make TSC frequency calculation dynamically
......................................................................

soc/intel/common/timer: Make TSC frequency calculation dynamically

tsc_freq_mhz() had a static table of Intel CPU families and crystal
clock, but it is possible to calculate the crystal clock speed dynamically,
and this is preferred over hardcoded table.

On SKL/KBL/CML CPUID.15h.ecx = nominal core crystal clock = 0 Hz
hence we had to use static table to calculate crystal clock.

Recommendation is to make use of CPUID.16h where crystal clock frequency
was not reported by CPUID.15h to calculate the crystal clock.

BUG=b:139798422, b:129839774
TEST=Able to build and boot KBL/CML/ICL.

Change-Id: If660a4b8d12e54b39252bce62bcc0ffcc967f5da
Signed-off-by: Subrata Banik 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/35148
Reviewed-by: Patrick Georgi 
Reviewed-by: V Sowmya 
Tested-by: build bot (Jenkins) 
---
D src/arch/x86/include/arch/intel-family.h
M src/soc/intel/common/block/timer/timer.c
2 files changed, 76 insertions(+), 117 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Patrick Georgi: Looks good to me, approved
  V Sowmya: Looks good to me, approved

diff --git a/src/arch/x86/include/arch/intel-family.h b/src/arch/x86/include/arch/intel-family.h
deleted file mode 100644
index 43eb0e6..0000000
--- a/src/arch/x86/include/arch/intel-family.h
+++ /dev/null
@@ -1,86 +0,0 @@
-/*
- * This file is part of the coreboot project.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; version 2 of the License.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- */
-
-#ifndef ARCH_INTEL_FAMILY_H
-#define ARCH_INTEL_FAMILY_H
-
-#define CPU_MODEL_INTEL_CORE_YONAH	0x0E
-
-#define CPU_MODEL_INTEL_CORE2_MEROM	0x0F
-#define CPU_MODEL_INTEL_CORE2_MEROM_L	0x16
-#define CPU_MODEL_INTEL_CORE2_PENRYN	0x17
-#define CPU_MODEL_INTEL_CORE2_DUNNINGTON	0x1D
-
-#define CPU_MODEL_INTEL_NEHALEM		0x1E
-/* Auburndale / Havendale */
-#define CPU_MODEL_INTEL_NEHALEM_G		0x1F
-#define CPU_MODEL_INTEL_NEHALEM_EP	0x1A
-#define CPU_MODEL_INTEL_NEHALEM_EX	0x2E
-
-#define CPU_MODEL_INTEL_WESTMERE		0x25
-#define CPU_MODEL_INTEL_WESTMERE_EP	0x2C
-#define CPU_MODEL_INTEL_WESTMERE_EX	0x2F
-
-#define CPU_MODEL_INTEL_SANDYBRIDGE	0x2A
-#define CPU_MODEL_INTEL_SANDYBRIDGE_X	0x2D
-#define CPU_MODEL_INTEL_IVYBRIDGE		0x3A
-#define CPU_MODEL_INTEL_IVYBRIDGE_X	0x3E
-
-#define CPU_MODEL_INTEL_HASWELL_CORE	0x3C
-#define CPU_MODEL_INTEL_HASWELL_X		0x3F
-#define CPU_MODEL_INTEL_HASWELL_ULT	0x45
-#define CPU_MODEL_INTEL_HASWELL_GT3E	0x46
-
-#define CPU_MODEL_INTEL_BROADWELL_CORE	0x3D
-#define CPU_MODEL_INTEL_BROADWELL_GT3E	0x47
-#define CPU_MODEL_INTEL_BROADWELL_X	0x4F
-#define CPU_MODEL_INTEL_BROADWELL_XEON_D	0x56
-
-#define CPU_MODEL_INTEL_SKYLAKE_MOBILE	0x4E
-#define CPU_MODEL_INTEL_SKYLAKE_DESKTOP	0x5E
-#define CPU_MODEL_INTEL_SKYLAKE_X		0x55
-#define CPU_MODEL_INTEL_KABYLAKE_MOBILE	0x8E
-#define CPU_MODEL_INTEL_KABYLAKE_DESKTOP	0x9E
-#define CPU_MODEL_INTEL_CANNONLAKE_MOBILE	0x66
-#define CPU_MODEL_INTEL_ICELAKE_MOBILE	0x7E
-
-/* "Small Core" Processors (Atom) */
-
-#define CPU_MODEL_INTEL_ATOM_PINEVIEW	0x1C
-#define CPU_MODEL_INTEL_ATOM_LINCROFT	0x26
-#define CPU_MODEL_INTEL_ATOM_PENWELL	0x27
-#define CPU_MODEL_INTEL_ATOM_CLOVERVIEW	0x35
-#define CPU_MODEL_INTEL_ATOM_CEDARVIEW	0x36
-/* BayTrail/BYT / Valleyview */
-#define CPU_MODEL_INTEL_ATOM_SILVERMONT1	0x37
-/* Avaton/Rangely */
-#define CPU_MODEL_INTEL_ATOM_SILVERMONT2	0x4D
-/* CherryTrail / Braswell */
-#define CPU_MODEL_INTEL_ATOM_AIRMONT	0x4C
-/* Tangier */
-#define CPU_MODEL_INTEL_ATOM_MERRIFIELD	0x4A
-/* Anniedale */
-#define CPU_MODEL_INTEL_ATOM_MOOREFIELD	0x5A
-#define CPU_MODEL_INTEL_ATOM_GOLDMONT	0x5C
-/* Goldmont Microserver */
-#define CPU_MODEL_INTEL_ATOM_DENVERTON	0x5F
-#define CPU_MODEL_INTEL_ATOM_GEMINI_LAKE	0x7A
-
-/* Xeon Phi */
-
-/* Knights Landing */
-#define CPU_MODEL_INTEL_XEON_PHI_KNL	0x57
-/* Knights Mill */
-#define CPU_MODEL_INTEL_XEON_PHI_KNM	0x85
-
-#endif /* ARCH_INTEL_FAMILY_H */
diff --git a/src/soc/intel/common/block/timer/timer.c b/src/soc/intel/common/block/timer/timer.c
index e60ac4d..8fde541 100644
--- a/src/soc/intel/common/block/timer/timer.c
+++ b/src/soc/intel/common/block/timer/timer.c
@@ -14,12 +14,14 @@
  */

#include <arch/cpu.h>
-#include <arch/intel-family.h>
 #include <cpu/cpu.h>
 #include <cpu/x86/msr.h>
 #include <cpu/x86/tsc.h>
 #include <intelblocks/msr.h>

+/* Goldmont Microserver */
+#define CPU_MODEL_INTEL_ATOM_DENVERTON 0x5F
+
 static int get_processor_model(void)
 {
    struct cpuinfo_x86 c;
@@ -29,8 +31,31 @@
    return c.x86_model;
 }

+static unsigned int get_max_cpuid_func(void)
+{
+	return cpuid_eax(0);
+}
+
+static unsigned long get_hardcoded_crystal_freq(void)
+{
+	unsigned int core_crystal_nominal_freq_khz;
+
+	/*
+	 * Denverton SoCs don't report crystal clock, and also don't support
+	 * CPUID.0x16, so hardcode the 25MHz crystal clock.
+	 */
+	switch (get_processor_model()) {
+	case CPU_MODEL_INTEL_ATOM_DENVERTON:
+		core_crystal_nominal_freq_khz = 25000;
+		break;
+	}
+
+	return core_crystal_nominal_freq_khz;
+}
+
 /*
- * Nominal TSC frequency = "core crystal clock frequency" * EBX/EAX
+ * Nominal TSC frequency = "core crystal clock frequency" *
+ *                               CPUID_15h.EBX/CPUID_15h.EAX
  *
  * Time Stamp Counter
  * CPUID Initial EAX value = 0x15
@@ -42,41 +67,61 @@
  * core crystal clock in Hz.
  * EDX Bit 31-0 : Reserved = 0
  *
- * Refer to Intel SDM Jan 2019 Vol 3B Section 18.7.3
  */
-unsigned long tsc_freq_mhz(void)
+static unsigned long calculate_tsc_freq_from_core_crystal(void)
 {
    unsigned int core_crystal_nominal_freq_khz;
-	struct cpuid_result cpuidr;
+	struct cpuid_result cpuidr_15h;

-	/* CPUID 15H TSC/Crystal ratio, plus optionally Crystal Hz */
-	cpuidr = cpuid(0x15);
-
-	if (!cpuidr.ebx || !cpuidr.eax)
+	if (get_max_cpuid_func() < 0x15)
    	return 0;

-	core_crystal_nominal_freq_khz = cpuidr.ecx / 1000;
+	/* CPUID 15H TSC/Crystal ratio, plus optionally Crystal Hz */
+	cpuidr_15h = cpuid(0x15);

-	if (!core_crystal_nominal_freq_khz) {
-		switch (get_processor_model()) {
-		case CPU_MODEL_INTEL_SKYLAKE_MOBILE:
-		case CPU_MODEL_INTEL_SKYLAKE_DESKTOP:
-		case CPU_MODEL_INTEL_KABYLAKE_MOBILE:
-		case CPU_MODEL_INTEL_KABYLAKE_DESKTOP:
-		case CPU_MODEL_INTEL_CANNONLAKE_MOBILE:
-		case CPU_MODEL_INTEL_ICELAKE_MOBILE:
-			core_crystal_nominal_freq_khz = 24000;
-			break;
-		case CPU_MODEL_INTEL_ATOM_DENVERTON:
-			core_crystal_nominal_freq_khz = 25000;
-			break;
-		case CPU_MODEL_INTEL_ATOM_GOLDMONT:
-		case CPU_MODEL_INTEL_ATOM_GEMINI_LAKE:
-			core_crystal_nominal_freq_khz = 19200;
-			break;
-		}
-	}
+	if (!cpuidr_15h.ebx || !cpuidr_15h.eax)
+		return 0;

-	return (core_crystal_nominal_freq_khz * cpuidr.ebx / cpuidr.eax) /
-			1000;
+	core_crystal_nominal_freq_khz = cpuidr_15h.ecx / 1000;
+
+	if (!core_crystal_nominal_freq_khz)
+		core_crystal_nominal_freq_khz = get_hardcoded_crystal_freq();
+
+	return (core_crystal_nominal_freq_khz * cpuidr_15h.ebx /
+			cpuidr_15h.eax) / 1000;
+}
+
+/*
+ * Processor Frequency Information
+ * CPUID Initial EAX value = 0x16
+ * EAX Bit 31-0 : An unsigned integer which has the processor base frequency
+ * information
+ * EBX Bit 31-0 : An unsigned integer which has maximum frequency information
+ * ECX Bit 31-0 : An unsigned integer which has bus frequency information
+ * EDX Bit 31-0 : Reserved = 0
+ *
+ * Refer to Intel SDM Jan 2019 Vol 3B Section 18.7.3
+ */
+static unsigned long get_freq_from_cpuid16h(void)
+{
+	if (get_max_cpuid_func() < 0x16)
+		return 0;
+
+	return cpuid_eax(0x16);
+}
+
+unsigned long tsc_freq_mhz(void)
+{
+	unsigned long tsc_freq;
+
+	tsc_freq = calculate_tsc_freq_from_core_crystal();
+
+	if (tsc_freq)
+		return tsc_freq;
+
+	/*
+	 * Some Intel SoCs like Skylake, Kabylake and Cometlake don't report
+	 * the crystal clock, in that case return bus frequency using CPUID.16h
+	 */
+	return get_freq_from_cpuid16h();
 }