soc/amd/cezanne: add ACPI CPPC support for AMD

This leverages the existing Collaborative Processor Performance Control
(CPPC) support and adds CPPC init for AMD/Cezanne.

BUG=b:185814875
TEST=under Linux/ChromeOS, acpidump ssdt2, find expected CPPC entries

Signed-off-by: Julian Schroeder <julianmarcusschroeder@gmail.com>
Change-Id: I94172f40c7fa4b7b89237fd382448e598da00fbb
Reviewed-on: https://review.coreboot.org/c/coreboot/+/56188
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>

5 files changed, 215 insertions, 0 deletions

diff --git a/src/soc/amd/cezanne/Makefile.inc b/src/soc/amd/cezanne/Makefile.inc
index d68a6b6290..478eeccac3 100644
--- a/src/soc/amd/cezanne/Makefile.inc
+++ b/src/soc/amd/cezanne/Makefile.inc
@@ -32,6 +32,8 @@ romstage-y	+= uart.c
 
 ramstage-y	+= i2c.c
 ramstage-y	+= acpi.c
+ramstage-y	+= cppc.c
+
 ramstage-y	+= agesa_acpi.c
 ramstage-y	+= chip.c
 ramstage-y	+= cpu.c
diff --git a/src/soc/amd/cezanne/acpi.c b/src/soc/amd/cezanne/acpi.c
index 6e2ae9ca0f..3b3a88befe 100644
--- a/src/soc/amd/cezanne/acpi.c
+++ b/src/soc/amd/cezanne/acpi.c
@@ -19,6 +19,7 @@
 #include <soc/msr.h>
 #include <types.h>
 #include "chip.h"
+#include <soc/cppc.h>
 
 unsigned long acpi_fill_madt(unsigned long current)
 {
@@ -358,6 +359,8 @@ void generate_cpu_entries(const struct device *device)
 		acpigen_write_CSD_package(cpu / threads_per_core, threads_per_core,
 					  CSD_HW_ALL, 0);
 
+		generate_cppc_entries(cpu);
+
 		acpigen_pop_len();
 	}
 
diff --git a/src/soc/amd/cezanne/cppc.c b/src/soc/amd/cezanne/cppc.c
new file mode 100644
index 0000000000..79292a4153
--- /dev/null
+++ b/src/soc/amd/cezanne/cppc.c
@@ -0,0 +1,180 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <acpi/acpi_pm.h>
+#include <acpi/acpigen.h>
+#include <arch/cpu.h>
+#include <soc/cppc.h>
+#include <soc/msr.h>
+
+/*
+ * version 2 is expected to be the typical use case.
+ * For now this function 'punts' on version 3 and just
+ * populates the additional fields with 'unsupported'.
+ */
+void cpu_init_cppc_config(struct cppc_config *config, u32 version)
+{
+	acpi_addr_t msr = {
+		.space_id   = ACPI_ADDRESS_SPACE_FIXED,
+		.bit_width  = 8,
+		.bit_offset = 0,
+		.access_size = ACPI_ACCESS_SIZE_QWORD_ACCESS,
+		.addrl      = 0,
+		.addrh      = 0,
+	};
+	static const acpi_addr_t unsupported = {
+		.space_id   = ACPI_ADDRESS_SPACE_MEMORY,
+		.bit_width  = 0,
+		.bit_offset = 0,
+		.access_size = ACPI_ACCESS_SIZE_UNDEFINED,
+		.addrl      = 0,
+		.addrh      = 0,
+	};
+
+	config->version = version;
+
+	/*
+	 * Highest Performance:
+	 */
+	msr.addrl = MSR_CPPC_CAPABILITY_1;
+	msr.bit_offset = SHIFT_CPPC_CAPABILITY_1_HIGHEST_PERF;
+	config->regs[CPPC_HIGHEST_PERF] = msr;
+
+	/*
+	 * Lowest Nonlinear Performance -> Most Efficient Performance:
+	 */
+	msr.bit_offset = SHIFT_CPPC_CAPABILITY_1_LOW_NON_LIN_PERF;
+	config->regs[CPPC_LOWEST_NONL_PERF] = msr;
+
+	/*
+	 * Lowest Performance:
+	 */
+	msr.bit_offset = SHIFT_CPPC_CAPABILITY_1_LOWEST_PERF;
+	config->regs[CPPC_LOWEST_PERF] = msr;
+
+	/*
+	 * Guaranteed Performance Register:
+	 */
+	config->regs[CPPC_GUARANTEED_PERF] = unsupported;
+
+	/*
+	 * Nominal Performance -> Maximum Non-Turbo Ratio:
+	 */
+	msr.bit_offset = SHIFT_CPPC_CAPABILITY_1_NOMINAL_PERF;
+	config->regs[CPPC_NOMINAL_PERF] = msr;
+
+	/*
+	 * Desired Performance Register:
+	 */
+	msr.addrl = MSR_CPPC_REQUEST;
+	msr.bit_offset = SHIFT_CPPC_REQUEST_DES_PERF;
+	config->regs[CPPC_DESIRED_PERF] = msr;
+
+	/*
+	 * Minimum Performance Register:
+	 */
+	msr.bit_offset = SHIFT_CPPC_REQUEST_MIN_PERF;
+	config->regs[CPPC_MIN_PERF] = msr;
+
+	/*
+	 * Maximum Performance Register:
+	 */
+	msr.bit_offset = SHIFT_CPPC_REQUEST_MAX_PERF;
+	config->regs[CPPC_MAX_PERF] = msr;
+
+	/*
+	 * Performance Reduction Tolerance Register:
+	 */
+	config->regs[CPPC_PERF_REDUCE_TOLERANCE] = unsupported;
+
+	/*
+	 * Time Window Register:
+	 */
+	config->regs[CPPC_TIME_WINDOW] = unsupported;
+
+	/*
+	 * Counter Wraparound Time:
+	 */
+	config->regs[CPPC_COUNTER_WRAP] = unsupported;
+
+	/*
+	 * Reference Performance Counter Register:
+	 */
+	msr.addrl = MSR_MAX_PERFORMANCE_FREQUENCY_CLOCK_COUNT;
+	msr.bit_width = 64;
+	msr.bit_offset = 0;
+	config->regs[CPPC_REF_PERF_COUNTER] = msr;
+
+	/*
+	 * Delivered Performance Counter Register:
+	 */
+	msr.addrl = MSR_ACTUAL_PERFORMANCE_FREQUENCY_CLOCK_COUNT;
+	config->regs[CPPC_DELIVERED_PERF_COUNTER] = msr;
+
+	/*
+	 * Performance Limited Register:
+	 */
+	msr.bit_width = 1;
+	msr.addrl = MSR_CPPC_STATUS;
+	msr.bit_offset = 1;
+	config->regs[CPPC_PERF_LIMITED] = msr;
+
+	/*
+	 * CPPC Enable Register:
+	 */
+	msr.addrl = MSR_CPPC_ENABLE;
+	msr.bit_offset = 0;
+	config->regs[CPPC_ENABLE] = msr;
+
+	if (version >= 2) {
+		/* Autonomous Selection Enable is populated below */
+
+		/*
+		 * Autonomous Activity Window Register
+		 */
+		config->regs[CPPC_AUTO_ACTIVITY_WINDOW] = unsupported;
+
+		/*
+		 * Autonomous Energy Performance Preference Register
+		 */
+		msr.addrl = MSR_CPPC_REQUEST;
+		msr.bit_width = 8;
+		msr.bit_offset = SHIFT_CPPC_REQUEST_ENERGY_PERF_PREF;
+		config->regs[CPPC_PERF_PREF] = msr;
+
+		/* Reference Performance */
+		config->regs[CPPC_REF_PERF] = unsupported;
+
+		if (version >= 3) {
+			/* Lowest Frequency */
+			config->regs[CPPC_LOWEST_FREQ] = unsupported;
+			/* Nominal Frequency */
+			config->regs[CPPC_NOMINAL_FREQ] = unsupported;
+		}
+
+		/*
+		 * Autonomous Selection Enable = 1
+		 * This field is actually the first addition in version 2 but
+		 * it's so unlike the others I'm populating it last.
+		 */
+		msr.space_id    = ACPI_ADDRESS_SPACE_MEMORY;
+		msr.bit_width   = 32;
+		msr.bit_offset  = 0;
+		msr.access_size = ACPI_ACCESS_SIZE_UNDEFINED;
+		msr.addrl       = 1;
+		config->regs[CPPC_AUTO_SELECT] = unsupported;
+	}
+}
+
+
+void generate_cppc_entries(unsigned int core_id)
+{
+	/* Generate GCPC package in first logical core */
+	if (core_id == 0) {
+		struct cppc_config cppc_config;
+		cpu_init_cppc_config(&cppc_config, CPPC_VERSION_3);
+		acpigen_write_CPPC_package(&cppc_config);
+	}
+
+	/* Write _CPC entry for each logical core */
+	acpigen_write_CPPC_method();
+}
diff --git a/src/soc/amd/cezanne/include/soc/cppc.h b/src/soc/amd/cezanne/include/soc/cppc.h
new file mode 100644
index 0000000000..60a5efd334
--- /dev/null
+++ b/src/soc/amd/cezanne/include/soc/cppc.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef _CPU_AMD_COMMON_H
+#define _CPU_AMD_COMMON_H
+
+#include <types.h>
+
+struct cppc_config;
+void cpu_init_cppc_config(struct cppc_config *config, u32 version);
+void generate_cppc_entries(unsigned int core_id);
+
+#endif
diff --git a/src/soc/amd/cezanne/include/soc/msr.h b/src/soc/amd/cezanne/include/soc/msr.h
index cc1f77e35b..ca2992a121 100644
--- a/src/soc/amd/cezanne/include/soc/msr.h
+++ b/src/soc/amd/cezanne/include/soc/msr.h
@@ -21,4 +21,22 @@
 #define PSTATE_DEF_LO_FREQ_MUL_MASK	(0xFF << PSTATE_DEF_LO_FREQ_MUL_SHIFT)
 #define PSTATE_DEF_LO_CORE_FREQ_BASE	25
 
+#define MSR_CPPC_CAPABILITY_1				0xc00102b0
+#define SHIFT_CPPC_CAPABILITY_1_HIGHEST_PERF		24
+#define SHIFT_CPPC_CAPABILITY_1_NOMINAL_PERF		16
+#define SHIFT_CPPC_CAPABILITY_1_LOW_NON_LIN_PERF	8
+#define SHIFT_CPPC_CAPABILITY_1_LOWEST_PERF		0
+
+#define MSR_CPPC_ENABLE				0xc00102b1
+#define MSR_CPPC_REQUEST			0xc00102b3
+#define SHIFT_CPPC_REQUEST_ENERGY_PERF_PREF	24
+#define SHIFT_CPPC_REQUEST_DES_PERF		16
+#define SHIFT_CPPC_REQUEST_MIN_PERF		8
+#define SHIFT_CPPC_REQUEST_MAX_PERF		0
+
+#define MSR_CPPC_STATUS		0xc00102b4
+
+#define MSR_MAX_PERFORMANCE_FREQUENCY_CLOCK_COUNT	0xe7
+#define MSR_ACTUAL_PERFORMANCE_FREQUENCY_CLOCK_COUNT	0xe8
+
 #endif /* AMD_CEZANNE_MSR_H */