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12ad6316bec56c66f829f3ba034b2cd632ac4ac6
linux/debian/patches/patchset-pf/amd-pstate/0027-cpufreq-amd-pstate-Rework-CPPC-enabling.patch
Konstantin Demin 12ad6316be release 6.14.1
2025-04-07 13:34:51 +03:00

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From bbb0d5ec2d1d757fc7b71086f505113845cc2aab Mon Sep 17 00:00:00 2001
From: Mario Limonciello <mario.limonciello@amd.com>
Date: Wed, 26 Feb 2025 01:49:32 -0600
Subject: cpufreq/amd-pstate: Rework CPPC enabling
The CPPC enable register is configured as "write once". That is
any future writes don't actually do anything.
Because of this, all the cleanup paths that currently exist for
CPPC disable are non-effective.
Rework CPPC enable to only enable after all the CAP registers have
been read to avoid enabling CPPC on CPUs with invalid _CPC or
unpopulated MSRs.
As the register is write once, remove all cleanup paths as well.
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
---
drivers/cpufreq/amd-pstate.c | 179 +++++++----------------------------
1 file changed, 35 insertions(+), 144 deletions(-)
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -85,7 +85,6 @@ static struct cpufreq_driver *current_ps
static struct cpufreq_driver amd_pstate_driver;
static struct cpufreq_driver amd_pstate_epp_driver;
static int cppc_state = AMD_PSTATE_UNDEFINED;
-static bool cppc_enabled;
static bool amd_pstate_prefcore = true;
static struct quirk_entry *quirks;
@@ -371,89 +370,21 @@ static int shmem_set_epp(struct cpufreq_
return ret;
}
-static int amd_pstate_set_energy_pref_index(struct cpufreq_policy *policy,
- int pref_index)
+static inline int msr_cppc_enable(struct cpufreq_policy *policy)
{
- struct amd_cpudata *cpudata = policy->driver_data;
- u8 epp;
-
- if (!pref_index)
- epp = cpudata->epp_default;
- else
- epp = epp_values[pref_index];
-
- if (epp > 0 && cpudata->policy == CPUFREQ_POLICY_PERFORMANCE) {
- pr_debug("EPP cannot be set under performance policy\n");
- return -EBUSY;
- }
-
- return amd_pstate_set_epp(policy, epp);
-}
-
-static inline int msr_cppc_enable(bool enable)
-{
- int ret, cpu;
- unsigned long logical_proc_id_mask = 0;
-
- /*
- * MSR_AMD_CPPC_ENABLE is write-once, once set it cannot be cleared.
- */
- if (!enable)
- return 0;
-
- if (enable == cppc_enabled)
- return 0;
-
- for_each_present_cpu(cpu) {
- unsigned long logical_id = topology_logical_package_id(cpu);
-
- if (test_bit(logical_id, &logical_proc_id_mask))
- continue;
-
- set_bit(logical_id, &logical_proc_id_mask);
-
- ret = wrmsrl_safe_on_cpu(cpu, MSR_AMD_CPPC_ENABLE,
- enable);
- if (ret)
- return ret;
- }
-
- cppc_enabled = enable;
- return 0;
+ return wrmsrl_safe_on_cpu(policy->cpu, MSR_AMD_CPPC_ENABLE, 1);
}
-static int shmem_cppc_enable(bool enable)
+static int shmem_cppc_enable(struct cpufreq_policy *policy)
{
- int cpu, ret = 0;
- struct cppc_perf_ctrls perf_ctrls;
-
- if (enable == cppc_enabled)
- return 0;
-
- for_each_present_cpu(cpu) {
- ret = cppc_set_enable(cpu, enable);
- if (ret)
- return ret;
-
- /* Enable autonomous mode for EPP */
- if (cppc_state == AMD_PSTATE_ACTIVE) {
- /* Set desired perf as zero to allow EPP firmware control */
- perf_ctrls.desired_perf = 0;
- ret = cppc_set_perf(cpu, &perf_ctrls);
- if (ret)
- return ret;
- }
- }
-
- cppc_enabled = enable;
- return ret;
+ return cppc_set_enable(policy->cpu, 1);
}
DEFINE_STATIC_CALL(amd_pstate_cppc_enable, msr_cppc_enable);
-static inline int amd_pstate_cppc_enable(bool enable)
+static inline int amd_pstate_cppc_enable(struct cpufreq_policy *policy)
{
- return static_call(amd_pstate_cppc_enable)(enable);
+ return static_call(amd_pstate_cppc_enable)(policy);
}
static int msr_init_perf(struct amd_cpudata *cpudata)
@@ -1063,6 +994,10 @@ static int amd_pstate_cpu_init(struct cp
cpudata->nominal_freq,
perf.highest_perf);
+ ret = amd_pstate_cppc_enable(policy);
+ if (ret)
+ goto free_cpudata1;
+
policy->boost_enabled = READ_ONCE(cpudata->boost_supported);
/* It will be updated by governor */
@@ -1110,28 +1045,6 @@ static void amd_pstate_cpu_exit(struct c
kfree(cpudata);
}
-static int amd_pstate_cpu_resume(struct cpufreq_policy *policy)
-{
- int ret;
-
- ret = amd_pstate_cppc_enable(true);
- if (ret)
- pr_err("failed to enable amd-pstate during resume, return %d\n", ret);
-
- return ret;
-}
-
-static int amd_pstate_cpu_suspend(struct cpufreq_policy *policy)
-{
- int ret;
-
- ret = amd_pstate_cppc_enable(false);
- if (ret)
- pr_err("failed to disable amd-pstate during suspend, return %d\n", ret);
-
- return ret;
-}
-
/* Sysfs attributes */
/*
@@ -1223,8 +1136,10 @@ static ssize_t show_energy_performance_a
static ssize_t store_energy_performance_preference(
struct cpufreq_policy *policy, const char *buf, size_t count)
{
+ struct amd_cpudata *cpudata = policy->driver_data;
char str_preference[21];
ssize_t ret;
+ u8 epp;
ret = sscanf(buf, "%20s", str_preference);
if (ret != 1)
@@ -1234,7 +1149,17 @@ static ssize_t store_energy_performance_
if (ret < 0)
return -EINVAL;
- ret = amd_pstate_set_energy_pref_index(policy, ret);
+ if (!ret)
+ epp = cpudata->epp_default;
+ else
+ epp = epp_values[ret];
+
+ if (epp > 0 && policy->policy == CPUFREQ_POLICY_PERFORMANCE) {
+ pr_debug("EPP cannot be set under performance policy\n");
+ return -EBUSY;
+ }
+
+ ret = amd_pstate_set_epp(policy, epp);
return ret ? ret : count;
}
@@ -1267,7 +1192,6 @@ static ssize_t show_energy_performance_p
static void amd_pstate_driver_cleanup(void)
{
- amd_pstate_cppc_enable(false);
cppc_state = AMD_PSTATE_DISABLE;
current_pstate_driver = NULL;
}
@@ -1301,14 +1225,6 @@ static int amd_pstate_register_driver(in
cppc_state = mode;
- ret = amd_pstate_cppc_enable(true);
- if (ret) {
- pr_err("failed to enable cppc during amd-pstate driver registration, return %d\n",
- ret);
- amd_pstate_driver_cleanup();
- return ret;
- }
-
/* at least one CPU supports CPB */
current_pstate_driver->boost_enabled = cpu_feature_enabled(X86_FEATURE_CPB);
@@ -1548,11 +1464,15 @@ static int amd_pstate_epp_cpu_init(struc
policy->cpuinfo.max_freq = policy->max = perf_to_freq(perf,
cpudata->nominal_freq,
perf.highest_perf);
+ policy->driver_data = cpudata;
+
+ ret = amd_pstate_cppc_enable(policy);
+ if (ret)
+ goto free_cpudata1;
/* It will be updated by governor */
policy->cur = policy->cpuinfo.min_freq;
- policy->driver_data = cpudata;
policy->boost_enabled = READ_ONCE(cpudata->boost_supported);
@@ -1644,31 +1564,11 @@ static int amd_pstate_epp_set_policy(str
return 0;
}
-static int amd_pstate_epp_reenable(struct cpufreq_policy *policy)
-{
- int ret;
-
- ret = amd_pstate_cppc_enable(true);
- if (ret)
- pr_err("failed to enable amd pstate during resume, return %d\n", ret);
-
-
- return amd_pstate_epp_update_limit(policy);
-}
-
static int amd_pstate_epp_cpu_online(struct cpufreq_policy *policy)
{
- struct amd_cpudata *cpudata = policy->driver_data;
- int ret;
-
- pr_debug("AMD CPU Core %d going online\n", cpudata->cpu);
+ pr_debug("AMD CPU Core %d going online\n", policy->cpu);
- ret = amd_pstate_epp_reenable(policy);
- if (ret)
- return ret;
- cpudata->suspended = false;
-
- return 0;
+ return amd_pstate_cppc_enable(policy);
}
static int amd_pstate_epp_cpu_offline(struct cpufreq_policy *policy)
@@ -1686,11 +1586,6 @@ static int amd_pstate_epp_cpu_offline(st
static int amd_pstate_epp_suspend(struct cpufreq_policy *policy)
{
struct amd_cpudata *cpudata = policy->driver_data;
- int ret;
-
- /* avoid suspending when EPP is not enabled */
- if (cppc_state != AMD_PSTATE_ACTIVE)
- return 0;
/* invalidate to ensure it's rewritten during resume */
cpudata->cppc_req_cached = 0;
@@ -1698,11 +1593,6 @@ static int amd_pstate_epp_suspend(struct
/* set this flag to avoid setting core offline*/
cpudata->suspended = true;
- /* disable CPPC in lowlevel firmware */
- ret = amd_pstate_cppc_enable(false);
- if (ret)
- pr_err("failed to suspend, return %d\n", ret);
-
return 0;
}
@@ -1711,8 +1601,12 @@ static int amd_pstate_epp_resume(struct
struct amd_cpudata *cpudata = policy->driver_data;
if (cpudata->suspended) {
+ int ret;
+
/* enable amd pstate from suspend state*/
- amd_pstate_epp_reenable(policy);
+ ret = amd_pstate_epp_update_limit(policy);
+ if (ret)
+ return ret;
cpudata->suspended = false;
}
@@ -1727,8 +1621,6 @@ static struct cpufreq_driver amd_pstate_
.fast_switch = amd_pstate_fast_switch,
.init = amd_pstate_cpu_init,
.exit = amd_pstate_cpu_exit,
- .suspend = amd_pstate_cpu_suspend,
- .resume = amd_pstate_cpu_resume,
.set_boost = amd_pstate_set_boost,
.update_limits = amd_pstate_update_limits,
.name = "amd-pstate",
@@ -1895,7 +1787,6 @@ static int __init amd_pstate_init(void)
global_attr_free:
cpufreq_unregister_driver(current_pstate_driver);
- amd_pstate_cppc_enable(false);
return ret;
}
device_initcall(amd_pstate_init);
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