From 11269ff506888a06b19c8c7a3297114f30673973 Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Tue, 4 Sep 2012 08:28:08 +0000 Subject: acpi-cpufreq: Add compatibility for legacy AMD cpb sysfs knob The powernow-k8 driver supported a sysfs knob called "cpb", which was instantiated per CPU, but actually acted globally for the whole system. To keep some compatibility with this feature, we re-introduce this behavior here, but: a) only enable it on AMD CPUs and b) protect it with a Kconfig switch I'd like to consider this feature obsolete. Lets keep it around for some kernel versions and then phase it out. Signed-off-by: Andre Przywara Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/acpi-cpufreq.c | 46 ++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 44 insertions(+), 2 deletions(-) (limited to 'drivers/cpufreq/acpi-cpufreq.c') diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c index dffa7af1db71..0d048f6a2b23 100644 --- a/drivers/cpufreq/acpi-cpufreq.c +++ b/drivers/cpufreq/acpi-cpufreq.c @@ -133,8 +133,7 @@ static void boost_set_msrs(bool enable, const struct cpumask *cpumask) wrmsr_on_cpus(cpumask, msr_addr, msrs); } -static ssize_t store_global_boost(struct kobject *kobj, struct attribute *attr, - const char *buf, size_t count) +static ssize_t _store_boost(const char *buf, size_t count) { int ret; unsigned long val = 0; @@ -161,6 +160,12 @@ static ssize_t store_global_boost(struct kobject *kobj, struct attribute *attr, return count; } +static ssize_t store_global_boost(struct kobject *kobj, struct attribute *attr, + const char *buf, size_t count) +{ + return _store_boost(buf, count); +} + static ssize_t show_global_boost(struct kobject *kobj, struct attribute *attr, char *buf) { @@ -171,6 +176,21 @@ static struct global_attr global_boost = __ATTR(boost, 0644, show_global_boost, store_global_boost); +#ifdef CONFIG_X86_ACPI_CPUFREQ_CPB +static ssize_t store_cpb(struct cpufreq_policy *policy, const char *buf, + size_t count) +{ + return _store_boost(buf, count); +} + +static ssize_t show_cpb(struct cpufreq_policy *policy, char *buf) +{ + return sprintf(buf, "%u\n", boost_enabled); +} + +static struct freq_attr cpb = __ATTR(cpb, 0644, show_cpb, store_cpb); +#endif + static int check_est_cpu(unsigned int cpuid) { struct cpuinfo_x86 *cpu = &cpu_data(cpuid); @@ -889,6 +909,7 @@ static int acpi_cpufreq_resume(struct cpufreq_policy *policy) static struct freq_attr *acpi_cpufreq_attr[] = { &cpufreq_freq_attr_scaling_available_freqs, + NULL, /* this is a placeholder for cpb, do not remove */ NULL, }; @@ -960,6 +981,27 @@ static int __init acpi_cpufreq_init(void) if (ret) return ret; +#ifdef CONFIG_X86_ACPI_CPUFREQ_CPB + /* this is a sysfs file with a strange name and an even stranger + * semantic - per CPU instantiation, but system global effect. + * Lets enable it only on AMD CPUs for compatibility reasons and + * only if configured. This is considered legacy code, which + * will probably be removed at some point in the future. + */ + if (check_amd_hwpstate_cpu(0)) { + struct freq_attr **iter; + + pr_debug("adding sysfs entry for cpb\n"); + + for (iter = acpi_cpufreq_attr; *iter != NULL; iter++) + ; + + /* make sure there is a terminator behind it */ + if (iter[1] == NULL) + *iter = &cpb; + } +#endif + ret = cpufreq_register_driver(&acpi_cpufreq_driver); if (ret) free_acpi_perf_data(); -- cgit v1.2.3