1 files changed, 44 insertions, 2 deletions

diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index e67e94b0ec14..3464580ac3ca 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -181,6 +181,49 @@ static void cppc_cpufreq_stop_cpu(struct cpufreq_policy *policy)
                                 cpu->perf_caps.lowest_perf, cpu_num, ret);
 }
 
+/*
+ * The PCC subspace describes the rate at which platform can accept commands
+ * on the shared PCC channel (including READs which do not count towards freq
+ * trasition requests), so ideally we need to use the PCC values as a fallback
+ * if we don't have a platform specific transition_delay_us
+ */
+#ifdef CONFIG_ARM64
+#include <asm/cputype.h>
+
+static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
+{
+        unsigned long implementor = read_cpuid_implementor();
+        unsigned long part_num = read_cpuid_part_number();
+        unsigned int delay_us = 0;
+
+        switch (implementor) {
+        case ARM_CPU_IMP_QCOM:
+                switch (part_num) {
+                case QCOM_CPU_PART_FALKOR_V1:
+                case QCOM_CPU_PART_FALKOR:
+                        delay_us = 10000;
+                        break;
+                default:
+                        delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
+                        break;
+                }
+                break;
+        default:
+                delay_us = cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
+                break;
+        }
+
+        return delay_us;
+}
+
+#else
+
+static unsigned int cppc_cpufreq_get_transition_delay_us(int cpu)
+{
+        return cppc_get_transition_latency(cpu) / NSEC_PER_USEC;
+}
+#endif
+
 static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
 {
         struct cppc_cpudata *cpu;
@@ -217,8 +260,7 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
         policy->cpuinfo.min_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.lowest_perf);
         policy->cpuinfo.max_freq = cppc_cpufreq_perf_to_khz(cpu, cpu->perf_caps.highest_perf);
 
-        policy->transition_delay_us = cppc_get_transition_latency(cpu_num) /
-                NSEC_PER_USEC;
+        policy->transition_delay_us = cppc_cpufreq_get_transition_delay_us(cpu_num);
         policy->shared_type = cpu->shared_type;
 
         if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY) {