cpufreq: amd-pstate: Add a kernel config option to set default mode

Users are having more success with amd-pstate since the introduction
of EPP and Guided modes.  To expose the driver to more users by default
introduce a kernel configuration option for setting the default mode.

Users can use an integer to map out which default mode they want to use
in lieu of a kernel command line option.

This will default to EPP, but only if:
 1) The CPU supports an MSR.
 2) The system profile is identified
 3) The system profile is identified as a non-server by the FADT.

Link: https://gitlab.freedesktop.org/hadess/power-profiles-daemon/-/merge_requests/121
Acked-by: Huang Rui <ray.huang@amd.com>
Reviewed-by: Gautham R. Shenoy <gautham.shenoy@amd.com>
Co-developed-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Perry Yuan <perry.yuan@amd.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/Kconfig.x86 b/drivers/cpufreq/Kconfig.x86
index 00476e94db9059d69cf890906d18c67eacb5dd2a..438c9e75a04dc83d8b75f359935dfb1b021af9a0 100644 (file)
--- a/drivers/cpufreq/Kconfig.x86
+++ b/drivers/cpufreq/Kconfig.x86
@@ -51,6 +51,23 @@ config X86_AMD_PSTATE
 
          If in doubt, say N.
 
+config X86_AMD_PSTATE_DEFAULT_MODE
+       int "AMD Processor P-State default mode"
+       depends on X86_AMD_PSTATE
+       default 3 if X86_AMD_PSTATE
+       range 1 4
+       help
+         Select the default mode the amd-pstate driver will use on
+         supported hardware.
+         The value set has the following meanings:
+               1 -> Disabled
+               2 -> Passive
+               3 -> Active (EPP)
+               4 -> Guided
+
+         For details, take a look at:
+         <file:Documentation/admin-guide/pm/amd-pstate.rst>.
+
 config X86_AMD_PSTATE_UT
        tristate "selftest for AMD Processor P-State driver"
        depends on X86 && ACPI_PROCESSOR

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 3546d7db614daaad776bff475fb61223be976189..81fba0dcbee9904afc610a0aa7bffe9ebba6760e 100644 (file)
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -62,7 +62,7 @@
 static struct cpufreq_driver *current_pstate_driver;
 static struct cpufreq_driver amd_pstate_driver;
 static struct cpufreq_driver amd_pstate_epp_driver;
-static int cppc_state = AMD_PSTATE_DISABLE;
+static int cppc_state = AMD_PSTATE_UNDEFINED;
 static bool cppc_enabled;
 
 /*
@@ -1410,6 +1410,25 @@ static struct cpufreq_driver amd_pstate_epp_driver = {
        .attr           = amd_pstate_epp_attr,
 };
 
+static int __init amd_pstate_set_driver(int mode_idx)
+{
+       if (mode_idx >= AMD_PSTATE_DISABLE && mode_idx < AMD_PSTATE_MAX) {
+               cppc_state = mode_idx;
+               if (cppc_state == AMD_PSTATE_DISABLE)
+                       pr_info("driver is explicitly disabled\n");
+
+               if (cppc_state == AMD_PSTATE_ACTIVE)
+                       current_pstate_driver = &amd_pstate_epp_driver;
+
+               if (cppc_state == AMD_PSTATE_PASSIVE || cppc_state == AMD_PSTATE_GUIDED)
+                       current_pstate_driver = &amd_pstate_driver;
+
+               return 0;
+       }
+
+       return -EINVAL;
+}
+
 static int __init amd_pstate_init(void)
 {
        struct device *dev_root;
@@ -1417,15 +1436,6 @@ static int __init amd_pstate_init(void)
 
        if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
                return -ENODEV;
-       /*
-        * by default the pstate driver is disabled to load
-        * enable the amd_pstate passive mode driver explicitly
-        * with amd_pstate=passive or other modes in kernel command line
-        */
-       if (cppc_state == AMD_PSTATE_DISABLE) {
-               pr_info("driver load is disabled, boot with specific mode to enable this\n");
-               return -ENODEV;
-       }
 
        if (!acpi_cpc_valid()) {
                pr_warn_once("the _CPC object is not present in SBIOS or ACPI disabled\n");
@@ -1436,6 +1446,33 @@ static int __init amd_pstate_init(void)
        if (cpufreq_get_current_driver())
                return -EEXIST;
 
+       switch (cppc_state) {
+       case AMD_PSTATE_UNDEFINED:
+               /* Disable on the following configs by default:
+                * 1. Undefined platforms
+                * 2. Server platforms
+                * 3. Shared memory designs
+                */
+               if (amd_pstate_acpi_pm_profile_undefined() ||
+                   amd_pstate_acpi_pm_profile_server() ||
+                   !boot_cpu_has(X86_FEATURE_CPPC)) {
+                       pr_info("driver load is disabled, boot with specific mode to enable this\n");
+                       return -ENODEV;
+               }
+               ret = amd_pstate_set_driver(CONFIG_X86_AMD_PSTATE_DEFAULT_MODE);
+               if (ret)
+                       return ret;
+               break;
+       case AMD_PSTATE_DISABLE:
+               return -ENODEV;
+       case AMD_PSTATE_PASSIVE:
+       case AMD_PSTATE_ACTIVE:
+       case AMD_PSTATE_GUIDED:
+               break;
+       default:
+               return -EINVAL;
+       }
+
        /* capability check */
        if (boot_cpu_has(X86_FEATURE_CPPC)) {
                pr_debug("AMD CPPC MSR based functionality is supported\n");
@@ -1488,21 +1525,7 @@ static int __init amd_pstate_param(char *str)
        size = strlen(str);
        mode_idx = get_mode_idx_from_str(str, size);
 
-       if (mode_idx >= AMD_PSTATE_DISABLE && mode_idx < AMD_PSTATE_MAX) {
-               cppc_state = mode_idx;
-               if (cppc_state == AMD_PSTATE_DISABLE)
-                       pr_info("driver is explicitly disabled\n");
-
-               if (cppc_state == AMD_PSTATE_ACTIVE)
-                       current_pstate_driver = &amd_pstate_epp_driver;
-
-               if (cppc_state == AMD_PSTATE_PASSIVE || cppc_state == AMD_PSTATE_GUIDED)
-                       current_pstate_driver = &amd_pstate_driver;
-
-               return 0;
-       }
-
-       return -EINVAL;
+       return amd_pstate_set_driver(mode_idx);
 }
 early_param("amd_pstate", amd_pstate_param);
 

diff --git a/include/linux/amd-pstate.h b/include/linux/amd-pstate.h
index c10ebf8c42e6b98feb8c152ab7b00f7c9783a9b3..446394f84606470e90892371d457dd9aad134663 100644 (file)
--- a/include/linux/amd-pstate.h
+++ b/include/linux/amd-pstate.h
@@ -94,7 +94,8 @@ struct amd_cpudata {
  * enum amd_pstate_mode - driver working mode of amd pstate
  */
 enum amd_pstate_mode {
-       AMD_PSTATE_DISABLE = 0,
+       AMD_PSTATE_UNDEFINED = 0,
+       AMD_PSTATE_DISABLE,
        AMD_PSTATE_PASSIVE,
        AMD_PSTATE_ACTIVE,
        AMD_PSTATE_GUIDED,
@@ -102,6 +103,7 @@ enum amd_pstate_mode {
 };
 
 static const char * const amd_pstate_mode_string[] = {
+       [AMD_PSTATE_UNDEFINED]   = "undefined",
        [AMD_PSTATE_DISABLE]     = "disable",
        [AMD_PSTATE_PASSIVE]     = "passive",
        [AMD_PSTATE_ACTIVE]      = "active",