summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--drivers/cpufreq/cppc_cpufreq.c53
1 files changed, 49 insertions, 4 deletions
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 8882b8e2ecd0..6debc189a9c9 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -19,10 +19,19 @@
#include <linux/delay.h>
#include <linux/cpu.h>
#include <linux/cpufreq.h>
+#include <linux/dmi.h>
#include <linux/vmalloc.h>
+#include <asm/unaligned.h>
+
#include <acpi/cppc_acpi.h>
+/* Minimum struct length needed for the DMI processor entry we want */
+#define DMI_ENTRY_PROCESSOR_MIN_LENGTH 48
+
+/* Offest in the DMI processor structure for the max frequency */
+#define DMI_PROCESSOR_MAX_SPEED 0x14
+
/*
* These structs contain information parsed from per CPU
* ACPI _CPC structures.
@@ -32,6 +41,39 @@
*/
static struct cpudata **all_cpu_data;
+/* Capture the max KHz from DMI */
+static u64 cppc_dmi_max_khz;
+
+/* Callback function used to retrieve the max frequency from DMI */
+static void cppc_find_dmi_mhz(const struct dmi_header *dm, void *private)
+{
+ const u8 *dmi_data = (const u8 *)dm;
+ u16 *mhz = (u16 *)private;
+
+ if (dm->type == DMI_ENTRY_PROCESSOR &&
+ dm->length >= DMI_ENTRY_PROCESSOR_MIN_LENGTH) {
+ u16 val = (u16)get_unaligned((const u16 *)
+ (dmi_data + DMI_PROCESSOR_MAX_SPEED));
+ *mhz = val > *mhz ? val : *mhz;
+ }
+}
+
+/* Look up the max frequency in DMI */
+static u64 cppc_get_dmi_max_khz(void)
+{
+ u16 mhz = 0;
+
+ dmi_walk(cppc_find_dmi_mhz, &mhz);
+
+ /*
+ * Real stupid fallback value, just in case there is no
+ * actual value set.
+ */
+ mhz = mhz ? mhz : 1;
+
+ return (1000 * mhz);
+}
+
static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
@@ -42,7 +84,7 @@ static int cppc_cpufreq_set_target(struct cpufreq_policy *policy,
cpu = all_cpu_data[policy->cpu];
- cpu->perf_ctrls.desired_perf = target_freq;
+ cpu->perf_ctrls.desired_perf = target_freq * policy->max / cppc_dmi_max_khz;
freqs.old = policy->cur;
freqs.new = target_freq;
@@ -94,8 +136,10 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
return ret;
}
- policy->min = cpu->perf_caps.lowest_perf;
- policy->max = cpu->perf_caps.highest_perf;
+ cppc_dmi_max_khz = cppc_get_dmi_max_khz();
+
+ policy->min = cpu->perf_caps.lowest_perf * cppc_dmi_max_khz / cpu->perf_caps.highest_perf;
+ policy->max = cppc_dmi_max_khz;
policy->cpuinfo.min_freq = policy->min;
policy->cpuinfo.max_freq = policy->max;
policy->shared_type = cpu->shared_type;
@@ -112,7 +156,8 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
cpu->cur_policy = policy;
/* Set policy->cur to max now. The governors will adjust later. */
- policy->cur = cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
+ policy->cur = cppc_dmi_max_khz;
+ cpu->perf_ctrls.desired_perf = cpu->perf_caps.highest_perf;
ret = cppc_set_perf(cpu_num, &cpu->perf_ctrls);
if (ret)