diff options
| -rw-r--r-- | drivers/cpufreq/cppc_cpufreq.c | 53 |
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) |