cpufreq/amd-pstate: Fix scaling_min_freq and scaling_max_freq update

When amd_pstate is running, writing to scaling_min_freq and
scaling_max_freq has no effect. These values are only passed to the
policy level, but not to the platform level. This means that the
platform does not know about the frequency limits set by the user.

To fix this, update the min_perf and max_perf values at the platform
level whenever the user changes the scaling_min_freq and scaling_max_freq
values.

Fixes: ffa5096a7c33 ("cpufreq: amd-pstate: implement Pstate EPP support for the AMD processors")
Acked-by: Huang Rui <[e-mail]>
Signed-off-by: Wyes Karny <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/cpufreq/amd-pstate.c

···
 		highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);
 
 	WRITE_ONCE(cpudata->highest_perf, highest_perf);
-
+	WRITE_ONCE(cpudata->max_limit_perf, highest_perf);
 	WRITE_ONCE(cpudata->nominal_perf, AMD_CPPC_NOMINAL_PERF(cap1));
 	WRITE_ONCE(cpudata->lowest_nonlinear_perf, AMD_CPPC_LOWNONLIN_PERF(cap1));
 	WRITE_ONCE(cpudata->lowest_perf, AMD_CPPC_LOWEST_PERF(cap1));
-
+	WRITE_ONCE(cpudata->min_limit_perf, AMD_CPPC_LOWEST_PERF(cap1));
 	return 0;
 }
 
···
 		highest_perf = cppc_perf.highest_perf;
 
 	WRITE_ONCE(cpudata->highest_perf, highest_perf);
-
+	WRITE_ONCE(cpudata->max_limit_perf, highest_perf);
 	WRITE_ONCE(cpudata->nominal_perf, cppc_perf.nominal_perf);
 	WRITE_ONCE(cpudata->lowest_nonlinear_perf,
 		   cppc_perf.lowest_nonlinear_perf);
 	WRITE_ONCE(cpudata->lowest_perf, cppc_perf.lowest_perf);
+	WRITE_ONCE(cpudata->min_limit_perf, cppc_perf.lowest_perf);
 
 	if (cppc_state == AMD_PSTATE_ACTIVE)
 		return 0;
···
 	u64 prev = READ_ONCE(cpudata->cppc_req_cached);
 	u64 value = prev;
 
+	min_perf = clamp_t(unsigned long, min_perf, cpudata->min_limit_perf,
+			cpudata->max_limit_perf);
+	max_perf = clamp_t(unsigned long, max_perf, cpudata->min_limit_perf,
+			cpudata->max_limit_perf);
 	des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf);
 
 	if ((cppc_state == AMD_PSTATE_GUIDED) && (gov_flags & CPUFREQ_GOV_DYNAMIC_SWITCHING)) {
···
 	return 0;
 }
 
+static int amd_pstate_update_min_max_limit(struct cpufreq_policy *policy)
+{
+	u32 max_limit_perf, min_limit_perf;
+	struct amd_cpudata *cpudata = policy->driver_data;
+
+	max_limit_perf = div_u64(policy->max * cpudata->highest_perf, cpudata->max_freq);
+	min_limit_perf = div_u64(policy->min * cpudata->highest_perf, cpudata->max_freq);
+
+	WRITE_ONCE(cpudata->max_limit_perf, max_limit_perf);
+	WRITE_ONCE(cpudata->min_limit_perf, min_limit_perf);
+	WRITE_ONCE(cpudata->max_limit_freq, policy->max);
+	WRITE_ONCE(cpudata->min_limit_freq, policy->min);
+
+	return 0;
+}
+
 static int amd_pstate_update_freq(struct cpufreq_policy *policy,
 				  unsigned int target_freq, bool fast_switch)
 {
···
 
 	if (!cpudata->max_freq)
 		return -ENODEV;
+
+	if (policy->min != cpudata->min_limit_freq || policy->max != cpudata->max_limit_freq)
+		amd_pstate_update_min_max_limit(policy);
 
 	cap_perf = READ_ONCE(cpudata->highest_perf);
 	min_perf = READ_ONCE(cpudata->lowest_perf);
···
 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 	struct amd_cpudata *cpudata = policy->driver_data;
 	unsigned int target_freq;
+
+	if (policy->min != cpudata->min_limit_freq || policy->max != cpudata->max_limit_freq)
+		amd_pstate_update_min_max_limit(policy);
+
 
 	cap_perf = READ_ONCE(cpudata->highest_perf);
 	lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf);
···
 	/* Initial processor data capability frequencies */
 	cpudata->max_freq = max_freq;
 	cpudata->min_freq = min_freq;
+	cpudata->max_limit_freq = max_freq;
+	cpudata->min_limit_freq = min_freq;
 	cpudata->nominal_freq = nominal_freq;
 	cpudata->lowest_nonlinear_freq = lowest_nonlinear_freq;
 
···
 	return 0;
 }
 
-static void amd_pstate_epp_init(unsigned int cpu)
+static void amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
 {
-	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 	struct amd_cpudata *cpudata = policy->driver_data;
-	u32 max_perf, min_perf;
+	u32 max_perf, min_perf, min_limit_perf, max_limit_perf;
 	u64 value;
 	s16 epp;
 
 	max_perf = READ_ONCE(cpudata->highest_perf);
 	min_perf = READ_ONCE(cpudata->lowest_perf);
+	max_limit_perf = div_u64(policy->max * cpudata->highest_perf, cpudata->max_freq);
+	min_limit_perf = div_u64(policy->min * cpudata->highest_perf, cpudata->max_freq);
+
+	max_perf = clamp_t(unsigned long, max_perf, cpudata->min_limit_perf,
+			cpudata->max_limit_perf);
+	min_perf = clamp_t(unsigned long, min_perf, cpudata->min_limit_perf,
+			cpudata->max_limit_perf);
+
+	WRITE_ONCE(cpudata->max_limit_perf, max_limit_perf);
+	WRITE_ONCE(cpudata->min_limit_perf, min_limit_perf);
 
 	value = READ_ONCE(cpudata->cppc_req_cached);
 
···
 	value &= ~AMD_CPPC_DES_PERF(~0L);
 	value |= AMD_CPPC_DES_PERF(0);
 
-	if (cpudata->epp_policy == cpudata->policy)
-		goto skip_epp;
-
 	cpudata->epp_policy = cpudata->policy;
 
 	/* Get BIOS pre-defined epp value */
···
 		 * This return value can only be negative for shared_memory
 		 * systems where EPP register read/write not supported.
 		 */
-		goto skip_epp;
+		return;
 	}
 
 	if (cpudata->policy == CPUFREQ_POLICY_PERFORMANCE)
···
 
 	WRITE_ONCE(cpudata->cppc_req_cached, value);
 	amd_pstate_set_epp(cpudata, epp);
-skip_epp:
-	cpufreq_cpu_put(policy);
 }
 
 static int amd_pstate_epp_set_policy(struct cpufreq_policy *policy)
···
 
 	cpudata->policy = policy->policy;
 
-	amd_pstate_epp_init(policy->cpu);
+	amd_pstate_epp_update_limit(policy);
 
 	return 0;
 }

include/linux/amd-pstate.h

···
 	u32	nominal_perf;
 	u32	lowest_nonlinear_perf;
 	u32	lowest_perf;
+	u32     min_limit_perf;
+	u32     max_limit_perf;
+	u32     min_limit_freq;
+	u32     max_limit_freq;
 
 	u32	max_freq;
 	u32	min_freq;