[CPUFREQ] e_powersaver: Check BIOS limit for CPU frequency
Call ACPI function to get BIOS limit for CPU frequency.
Fail if processor would like to run at higher frequency.
Allow user to ignore BIOS limit.
eps: Detected VIA Model D C7-M
eps: Current voltage = 1084mV
eps: Current multiplier = 16
eps: Highest voltage = 1084mV
eps: Highest multiplier = 16
eps: Lowest voltage = 844mV
eps: Lowest multiplier = 4
eps: ACPI limit 1.60GHz
Signed-off-by: Rafał Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>
diff --git a/drivers/cpufreq/e_powersaver.c b/drivers/cpufreq/e_powersaver.c
index 84661c5..2882d40 100644
--- a/drivers/cpufreq/e_powersaver.c
+++ b/drivers/cpufreq/e_powersaver.c
@@ -19,6 +19,11 @@
#include <asm/msr.h>
#include <asm/tsc.h>
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+#include <linux/acpi.h>
+#include <acpi/processor.h>
+#endif
+
#define EPS_BRAND_C7M 0
#define EPS_BRAND_C7 1
#define EPS_BRAND_EDEN 2
@@ -27,6 +32,9 @@
struct eps_cpu_data {
u32 fsb;
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+ u32 bios_limit;
+#endif
struct cpufreq_frequency_table freq_table[];
};
@@ -36,6 +44,46 @@
static int freq_failsafe_off;
static int voltage_failsafe_off;
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+static int ignore_acpi_limit;
+
+static struct acpi_processor_performance *eps_acpi_cpu_perf;
+
+/* Minimum necessary to get acpi_processor_get_bios_limit() working */
+static int eps_acpi_init(void)
+{
+ eps_acpi_cpu_perf = kzalloc(sizeof(struct acpi_processor_performance),
+ GFP_KERNEL);
+ if (!eps_acpi_cpu_perf)
+ return -ENOMEM;
+
+ if (!zalloc_cpumask_var(&eps_acpi_cpu_perf->shared_cpu_map,
+ GFP_KERNEL)) {
+ kfree(eps_acpi_cpu_perf);
+ eps_acpi_cpu_perf = NULL;
+ return -ENOMEM;
+ }
+
+ if (acpi_processor_register_performance(eps_acpi_cpu_perf, 0)) {
+ free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
+ kfree(eps_acpi_cpu_perf);
+ eps_acpi_cpu_perf = NULL;
+ return -EIO;
+ }
+ return 0;
+}
+
+static int eps_acpi_exit(struct cpufreq_policy *policy)
+{
+ if (eps_acpi_cpu_perf) {
+ acpi_processor_unregister_performance(eps_acpi_cpu_perf, 0);
+ free_cpumask_var(eps_acpi_cpu_perf->shared_cpu_map);
+ kfree(eps_acpi_cpu_perf);
+ eps_acpi_cpu_perf = NULL;
+ }
+ return 0;
+}
+#endif
static unsigned int eps_get(unsigned int cpu)
{
@@ -168,6 +216,9 @@
int k, step, voltage;
int ret;
int states;
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+ unsigned int limit;
+#endif
if (policy->cpu != 0)
return -ENODEV;
@@ -271,6 +322,24 @@
/* Calc FSB speed */
fsb = cpu_khz / current_multiplier;
+
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+ /* Check for ACPI processor speed limit */
+ if (!ignore_acpi_limit && !eps_acpi_init()) {
+ if (!acpi_processor_get_bios_limit(policy->cpu, &limit)) {
+ printk(KERN_INFO "eps: ACPI limit %u.%uGHz\n",
+ limit/1000000,
+ (limit%1000000)/10000);
+ eps_acpi_exit(policy);
+ /* Check if max_multiplier is in BIOS limits */
+ if (limit && max_multiplier * fsb > limit) {
+ printk(KERN_INFO "eps: Aborting.\n");
+ return -EINVAL;
+ }
+ }
+ }
+#endif
+
/* Calc number of p-states supported */
if (brand == EPS_BRAND_C7M)
states = max_multiplier - min_multiplier + 1;
@@ -287,6 +356,9 @@
/* Copy basic values */
centaur->fsb = fsb;
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+ centaur->bios_limit = limit;
+#endif
/* Fill frequency and MSR value table */
f_table = ¢aur->freq_table[0];
@@ -377,6 +449,10 @@
MODULE_PARM_DESC(freq_failsafe_off, "Disable current vs max frequency check");
module_param(voltage_failsafe_off, int, 0644);
MODULE_PARM_DESC(voltage_failsafe_off, "Disable current vs max voltage check");
+#if defined CONFIG_ACPI_PROCESSOR || defined CONFIG_ACPI_PROCESSOR_MODULE
+module_param(ignore_acpi_limit, int, 0644);
+MODULE_PARM_DESC(ignore_acpi_limit, "Don't check ACPI's processor speed limit");
+#endif
MODULE_AUTHOR("Rafal Bilski <rafalbilski@interia.pl>");
MODULE_DESCRIPTION("Enhanced PowerSaver driver for VIA C7 CPU's.");