diff options
Diffstat (limited to 'drivers/acpi/acpi_processor.c')
| -rw-r--r-- | drivers/acpi/acpi_processor.c | 42 |
1 files changed, 40 insertions, 2 deletions
diff --git a/drivers/acpi/acpi_processor.c b/drivers/acpi/acpi_processor.c index 6737b1cbf6d6..f9aa02cac6d1 100644 --- a/drivers/acpi/acpi_processor.c +++ b/drivers/acpi/acpi_processor.c @@ -15,6 +15,7 @@ #include <linux/kernel.h> #include <linux/module.h> #include <linux/pci.h> +#include <linux/platform_device.h> #include <acpi/processor.h> @@ -148,6 +149,34 @@ static int acpi_processor_errata(void) return result; } +/* Create a platform device to represent a CPU frequency control mechanism. */ +static void cpufreq_add_device(const char *name) +{ + struct platform_device *pdev; + + pdev = platform_device_register_simple(name, PLATFORM_DEVID_NONE, NULL, 0); + if (IS_ERR(pdev)) + pr_info("%s device creation failed: %ld\n", name, PTR_ERR(pdev)); +} + +#ifdef CONFIG_X86 +/* Check presence of Processor Clocking Control by searching for \_SB.PCCH. */ +static void __init acpi_pcc_cpufreq_init(void) +{ + acpi_status status; + acpi_handle handle; + + status = acpi_get_handle(NULL, "\\_SB", &handle); + if (ACPI_FAILURE(status)) + return; + + if (acpi_has_method(handle, "PCCH")) + cpufreq_add_device("pcc-cpufreq"); +} +#else +static void __init acpi_pcc_cpufreq_init(void) {} +#endif /* CONFIG_X86 */ + /* Initialization */ #ifdef CONFIG_ACPI_HOTPLUG_CPU int __weak acpi_map_cpu(acpi_handle handle, @@ -280,14 +309,22 @@ static int acpi_processor_get_info(struct acpi_device *device) dev_dbg(&device->dev, "Failed to get CPU physical ID.\n"); pr->id = acpi_map_cpuid(pr->phys_id, pr->acpi_id); - if (!cpu0_initialized && !acpi_has_cpu_in_madt()) { + if (!cpu0_initialized) { cpu0_initialized = 1; /* * Handle UP system running SMP kernel, with no CPU * entry in MADT */ - if (invalid_logical_cpuid(pr->id) && (num_online_cpus() == 1)) + if (!acpi_has_cpu_in_madt() && invalid_logical_cpuid(pr->id) && + (num_online_cpus() == 1)) pr->id = 0; + /* + * Check availability of Processor Performance Control by + * looking at the presence of the _PCT object under the first + * processor definition. + */ + if (acpi_has_method(pr->handle, "_PCT")) + cpufreq_add_device("acpi-cpufreq"); } /* @@ -686,6 +723,7 @@ void __init acpi_processor_init(void) acpi_processor_check_duplicates(); acpi_scan_add_handler_with_hotplug(&processor_handler, "processor"); acpi_scan_add_handler(&processor_container_handler); + acpi_pcc_cpufreq_init(); } #ifdef CONFIG_ACPI_PROCESSOR_CSTATE |