acpi-cpufreq: Add support for modern AMD CPUs

The programming model for P-states on modern AMD CPUs is very similar to
that of Intel and VIA. It makes sense to consolidate this support into one
driver rather than duplicating functionality between two of them. This
patch adds support for AMDs with hardware P-state control to acpi-cpufreq.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

2 files changed, 39 insertions, 7 deletions

diff --git a/drivers/cpufreq/Kconfig.x86 b/drivers/cpufreq/Kconfig.x86
index 78ff7ee48951..8d12e378a7ef 100644
--- a/drivers/cpufreq/Kconfig.x86
+++ b/drivers/cpufreq/Kconfig.x86
@@ -23,7 +23,8 @@ config X86_ACPI_CPUFREQ
         help
           This driver adds a CPUFreq driver which utilizes the ACPI
           Processor Performance States.
-          This driver also supports Intel Enhanced Speedstep.
+          This driver also supports Intel Enhanced Speedstep and newer
+          AMD CPUs.
 
           To compile this driver as a module, choose M here: the
           module will be called acpi-cpufreq.
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 56c6c6b4eb4d..067a61f06bb5 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -54,10 +54,12 @@ MODULE_LICENSE("GPL");
 enum {
         UNDEFINED_CAPABLE = 0,
         SYSTEM_INTEL_MSR_CAPABLE,
+        SYSTEM_AMD_MSR_CAPABLE,
         SYSTEM_IO_CAPABLE,
 };
 
 #define INTEL_MSR_RANGE         (0xffff)
+#define AMD_MSR_RANGE           (0x7)
 
 struct acpi_cpufreq_data {
         struct acpi_processor_performance *acpi_data;
@@ -82,6 +84,13 @@ static int check_est_cpu(unsigned int cpuid)
         return cpu_has(cpu, X86_FEATURE_EST);
 }
 
+static int check_amd_hwpstate_cpu(unsigned int cpuid)
+{
+        struct cpuinfo_x86 *cpu = &cpu_data(cpuid);
+
+        return cpu_has(cpu, X86_FEATURE_HW_PSTATE);
+}
+
 static unsigned extract_io(u32 value, struct acpi_cpufreq_data *data)
 {
         struct acpi_processor_performance *perf;
@@ -101,7 +110,11 @@ static unsigned extract_msr(u32 msr, struct acpi_cpufreq_data *data)
         int i;
         struct acpi_processor_performance *perf;
 
-        msr &= INTEL_MSR_RANGE;
+        if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
+                msr &= AMD_MSR_RANGE;
+        else
+                msr &= INTEL_MSR_RANGE;
+
         perf = data->acpi_data;
 
         for (i = 0; data->freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
@@ -115,6 +128,7 @@ static unsigned extract_freq(u32 val, struct acpi_cpufreq_data *data)
 {
         switch (data->cpu_feature) {
         case SYSTEM_INTEL_MSR_CAPABLE:
+        case SYSTEM_AMD_MSR_CAPABLE:
                 return extract_msr(val, data);
         case SYSTEM_IO_CAPABLE:
                 return extract_io(val, data);
@@ -150,6 +164,7 @@ static void do_drv_read(void *_cmd)
 
         switch (cmd->type) {
         case SYSTEM_INTEL_MSR_CAPABLE:
+        case SYSTEM_AMD_MSR_CAPABLE:
                 rdmsr(cmd->addr.msr.reg, cmd->val, h);
                 break;
         case SYSTEM_IO_CAPABLE:
@@ -174,6 +189,9 @@ static void do_drv_write(void *_cmd)
                 lo = (lo & ~INTEL_MSR_RANGE) | (cmd->val & INTEL_MSR_RANGE);
                 wrmsr(cmd->addr.msr.reg, lo, hi);
                 break;
+        case SYSTEM_AMD_MSR_CAPABLE:
+                wrmsr(cmd->addr.msr.reg, cmd->val, 0);
+                break;
         case SYSTEM_IO_CAPABLE:
                 acpi_os_write_port((acpi_io_address)cmd->addr.io.port,
                                 cmd->val,
@@ -217,6 +235,10 @@ static u32 get_cur_val(const struct cpumask *mask)
                 cmd.type = SYSTEM_INTEL_MSR_CAPABLE;
                 cmd.addr.msr.reg = MSR_IA32_PERF_STATUS;
                 break;
+        case SYSTEM_AMD_MSR_CAPABLE:
+                cmd.type = SYSTEM_AMD_MSR_CAPABLE;
+                cmd.addr.msr.reg = MSR_AMD_PERF_STATUS;
+                break;
         case SYSTEM_IO_CAPABLE:
                 cmd.type = SYSTEM_IO_CAPABLE;
                 perf = per_cpu(acfreq_data, cpumask_first(mask))->acpi_data;
@@ -326,6 +348,11 @@ static int acpi_cpufreq_target(struct cpufreq_policy *policy,
                 cmd.addr.msr.reg = MSR_IA32_PERF_CTL;
                 cmd.val = (u32) perf->states[next_perf_state].control;
                 break;
+        case SYSTEM_AMD_MSR_CAPABLE:
+                cmd.type = SYSTEM_AMD_MSR_CAPABLE;
+                cmd.addr.msr.reg = MSR_AMD_PERF_CTL;
+                cmd.val = (u32) perf->states[next_perf_state].control;
+                break;
         case SYSTEM_IO_CAPABLE:
                 cmd.type = SYSTEM_IO_CAPABLE;
                 cmd.addr.io.port = perf->control_register.address;
@@ -580,12 +607,16 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
                 break;
         case ACPI_ADR_SPACE_FIXED_HARDWARE:
                 pr_debug("HARDWARE addr space\n");
-                if (!check_est_cpu(cpu)) {
-                        result = -ENODEV;
-                        goto err_unreg;
+                if (check_est_cpu(cpu)) {
+                        data->cpu_feature = SYSTEM_INTEL_MSR_CAPABLE;
+                        break;
                 }
-                data->cpu_feature = SYSTEM_INTEL_MSR_CAPABLE;
-                break;
+                if (check_amd_hwpstate_cpu(cpu)) {
+                        data->cpu_feature = SYSTEM_AMD_MSR_CAPABLE;
+                        break;
+                }
+                result = -ENODEV;
+                goto err_unreg;
         default:
                 pr_debug("Unknown addr space %d\n",
                         (u32) (perf->control_register.space_id));