/* * processor_thermal.c - Passive cooling submodule of the ACPI processor driver * * Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com> * Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com> * Copyright (C) 2004 Dominik Brodowski <linux@brodo.de> * Copyright (C) 2004 Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> * - Added processor hotplug support * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or (at * your option) any later version. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License along * with this program; if not, write to the Free Software Foundation, Inc., * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/cpufreq.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/sysdev.h> #include <asm/uaccess.h> #include <acpi/acpi_bus.h> #include <acpi/processor.h> #include <acpi/acpi_drivers.h> #define PREFIX "ACPI: " #define ACPI_PROCESSOR_CLASS "processor" #define _COMPONENT ACPI_PROCESSOR_COMPONENT ACPI_MODULE_NAME("processor_thermal"); /* -------------------------------------------------------------------------- Limit Interface -------------------------------------------------------------------------- */ static int acpi_processor_apply_limit(struct acpi_processor *pr) { int result = 0; u16 px = 0; u16 tx = 0; if (!pr) return -EINVAL; if (!pr->flags.limit) return -ENODEV; if (pr->flags.throttling) { if (pr->limit.user.tx > tx) tx = pr->limit.user.tx; if (pr->limit.thermal.tx > tx) tx = pr->limit.thermal.tx; result = acpi_processor_set_throttling(pr, tx, false); if (result) goto end; } pr->limit.state.px = px; pr->limit.state.tx = tx; ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor [%d] limit set to (P%d:T%d)\n", pr->id, pr->limit.state.px, pr->limit.state.tx)); end: if (result) printk(KERN_ERR PREFIX "Unable to set limit\n"); return result; } #ifdef CONFIG_CPU_FREQ /* If a passive cooling situation is detected, primarily CPUfreq is used, as it * offers (in most cases) voltage scaling in addition to frequency scaling, and * thus a cubic (instead of linear) reduction of energy. Also, we allow for * _any_ cpufreq driver and not only the acpi-cpufreq driver. */ #define CPUFREQ_THERMAL_MIN_STEP 0 #define CPUFREQ_THERMAL_MAX_STEP 3 static DEFINE_PER_CPU(unsigned int, cpufreq_thermal_reduction_pctg); static unsigned int acpi_thermal_cpufreq_is_init = 0; static int cpu_has_cpufreq(unsigned int cpu) { struct cpufreq_policy policy; if (!acpi_thermal_cpufreq_is_init || cpufreq_get_policy(&policy, cpu)) return 0; return 1; } static int acpi_thermal_cpufreq_increase(unsigned int cpu) { if (!cpu_has_cpufreq(cpu)) return -ENODEV; if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) < CPUFREQ_THERMAL_MAX_STEP) { per_cpu(cpufreq_thermal_reduction_pctg, cpu)++; cpufreq_update_policy(cpu); return 0; } return -ERANGE; } static int acpi_thermal_cpufreq_decrease(unsigned int cpu) { if (!cpu_has_cpufreq(cpu)) return -ENODEV; if (per_cpu(cpufreq_thermal_reduction_pctg, cpu) > (CPUFREQ_THERMAL_MIN_STEP + 1)) per_cpu(cpufreq_thermal_reduction_pctg, cpu)--; else per_cpu(cpufreq_thermal_reduction_pctg, cpu) = 0; cpufreq_update_policy(cpu); /* We reached max freq again and can leave passive mode */ return !per_cpu(cpufreq_thermal_reduction_pctg, cpu); } static int acpi_thermal_cpufreq_notifier(struct notifier_block *nb, unsigned long event, void *data) { struct cpufreq_policy *policy = data; unsigned long max_freq = 0; if (event != CPUFREQ_ADJUST) goto out; max_freq = ( policy->cpuinfo.max_freq * (100 - per_cpu(cpufreq_thermal_reduction_pctg, policy->cpu) * 20) ) / 100; cpufreq_verify_within_limits(policy, 0, max_freq); out: return 0; } static struct notifier_block acpi_thermal_cpufreq_notifier_block = { .notifier_call = acpi_thermal_cpufreq_notifier, }; static int cpufreq_get_max_state(unsigned int cpu) { if (!cpu_has_cpufreq(cpu)) return 0; return CPUFREQ_THERMAL_MAX_STEP; } static int cpufreq_get_cur_state(unsigned int cpu) { if (!cpu_has_cpufreq(cpu)) return 0; return per_cpu(cpufreq_thermal_reduction_pctg, cpu); } static int cpufreq_set_cur_state(unsigned int cpu, int state) { if (!cpu_has_cpufreq(cpu)) return 0; per_cpu(cpufreq_thermal_reduction_pctg, cpu) = state; cpufreq_update_policy(cpu); return 0; } void acpi_thermal_cpufreq_init(void) { int i; for (i = 0; i < nr_cpu_ids; i++) if (cpu_present(i)) per_cpu(cpufreq_thermal_reduction_pctg, i) = 0; i = cpufreq_register_notifier(&acpi_thermal_cpufreq_notifier_block, CPUFREQ_POLICY_NOTIFIER); if (!i) acpi_thermal_cpufreq_is_init = 1; } void acpi_thermal_cpufreq_exit(void) { if (acpi_thermal_cpufreq_is_init) cpufreq_unregister_notifier (&acpi_thermal_cpufreq_notifier_block, CPUFREQ_POLICY_NOTIFIER); acpi_thermal_cpufreq_is_init = 0; } #else /* ! CONFIG_CPU_FREQ */ static int cpufreq_get_max_state(unsigned int cpu) { return 0; } static int cpufreq_get_cur_state(unsigned int cpu) { return 0; } static int cpufreq_set_cur_state(unsigned int cpu, int state) { return 0; } static int acpi_thermal_cpufreq_increase(unsigned int cpu) { return -ENODEV; } static int acpi_thermal_cpufreq_decrease(unsigned int cpu) { return -ENODEV; } #endif int acpi_processor_set_thermal_limit(acpi_handle handle, int type) { int result = 0; struct acpi_processor *pr = NULL; struct acpi_device *device = NULL; int tx = 0, max_tx_px = 0; if ((type < ACPI_PROCESSOR_LIMIT_NONE) || (type > ACPI_PROCESSOR_LIMIT_DECREMENT)) return -EINVAL; result = acpi_bus_get_device(handle, &device); if (result) return result; pr = acpi_driver_data(device); if (!pr) return -ENODEV; /* Thermal limits are always relative to the current Px/Tx state. */ if (pr->flags.throttling) pr->limit.thermal.tx = pr->throttling.state; /* * Our default policy is to only use throttling at the lowest * performance state. */ tx = pr->limit.thermal.tx; switch (type) { case ACPI_PROCESSOR_LIMIT_NONE: do { result = acpi_thermal_cpufreq_decrease(pr->id); } while (!result); tx = 0; break; case ACPI_PROCESSOR_LIMIT_INCREMENT: /* if going up: P-states first, T-states later */ result = acpi_thermal_cpufreq_increase(pr->id); if (!result) goto end; else if (result == -ERANGE) ACPI_DEBUG_PRINT((ACPI_DB_INFO, "At maximum performance state\n")); if (pr->flags.throttling) { if (tx == (pr->throttling.state_count - 1)) ACPI_DEBUG_PRINT((ACPI_DB_INFO, "At maximum throttling state\n")); else tx++; } break; case ACPI_PROCESSOR_LIMIT_DECREMENT: /* if going down: T-states first, P-states later */ if (pr->flags.throttling) { if (tx == 0) { max_tx_px = 1; ACPI_DEBUG_PRINT((ACPI_DB_INFO, "At minimum throttling state\n")); } else { tx--; goto end; } } result = acpi_thermal_cpufreq_decrease(pr->id); if (result) { /* * We only could get -ERANGE, 1 or 0. * In the first two cases we reached max freq again. */ ACPI_DEBUG_PRINT((ACPI_DB_INFO, "At minimum performance state\n")); max_tx_px = 1; } else max_tx_px = 0; break; } end: if (pr->flags.throttling) { pr->limit.thermal.px = 0; pr->limit.thermal.tx = tx; result = acpi_processor_apply_limit(pr); if (result) printk(KERN_ERR PREFIX "Unable to set thermal limit\n"); ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Thermal limit now (P%d:T%d)\n", pr->limit.thermal.px, pr->limit.thermal.tx)); } else result = 0; if (max_tx_px) return 1; else return result; } int acpi_processor_get_limit_info(struct acpi_processor *pr) { if (!pr) return -EINVAL; if (pr->flags.throttling) pr->flags.limit = 1; return 0; } /* thermal coolign device callbacks */ static int acpi_processor_max_state(struct acpi_processor *pr) { int max_state = 0; /* * There exists four states according to * cpufreq_thermal_reduction_ptg. 0, 1, 2, 3 */ max_state += cpufreq_get_max_state(pr->id); if (pr->flags.throttling) max_state += (pr->throttling.state_count -1); return max_state; } static int processor_get_max_state(struct thermal_cooling_device *cdev, unsigned long *state) { struct acpi_device *device = cdev->devdata; struct acpi_processor *pr = acpi_driver_data(device); if (!device || !pr) return -EINVAL; *state = acpi_processor_max_state(pr); return 0; } static int processor_get_cur_state(struct thermal_cooling_device *cdev, unsigned long *cur_state) { struct acpi_device *device = cdev->devdata; struct acpi_processor *pr = acpi_driver_data(device); if (!device || !pr) return -EINVAL; *cur_state = cpufreq_get_cur_state(pr->id); if (pr->flags.throttling) *cur_state += pr->throttling.state; return 0; } static int processor_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state) { struct acpi_device *device = cdev->devdata; struct acpi_processor *pr = acpi_driver_data(device); int result = 0; int max_pstate; if (!device || !pr) return -EINVAL; max_pstate = cpufreq_get_max_state(pr->id); if (state > acpi_processor_max_state(pr)) return -EINVAL; if (state <= max_pstate) { if (pr->flags.throttling && pr->throttling.state) result = acpi_processor_set_throttling(pr, 0, false); cpufreq_set_cur_state(pr->id, state); } else { cpufreq_set_cur_state(pr->id, max_pstate); result = acpi_processor_set_throttling(pr, state - max_pstate, false); } return result; } struct thermal_cooling_device_ops processor_cooling_ops = { .get_max_state = processor_get_max_state, .get_cur_state = processor_get_cur_state, .set_cur_state = processor_set_cur_state, }; /* /proc interface */ #ifdef CONFIG_ACPI_PROCFS static int acpi_processor_limit_seq_show(struct seq_file *seq, void *offset) { struct acpi_processor *pr = (struct acpi_processor *)seq->private; if (!pr) goto end; if (!pr->flags.limit) { seq_puts(seq, "<not supported>\n"); goto end; } seq_printf(seq, "active limit: P%d:T%d\n" "user limit: P%d:T%d\n" "thermal limit: P%d:T%d\n", pr->limit.state.px, pr->limit.state.tx, pr->limit.user.px, pr->limit.user.tx, pr->limit.thermal.px, pr->limit.thermal.tx); end: return 0; } static int acpi_processor_limit_open_fs(struct inode *inode, struct file *file) { return single_open(file, acpi_processor_limit_seq_show, PDE(inode)->data); } static ssize_t acpi_processor_write_limit(struct file * file, const char __user * buffer, size_t count, loff_t * data) { int result = 0; struct seq_file *m = file->private_data; struct acpi_processor *pr = m->private; char limit_string[25] = { '\0' }; int px = 0; int tx = 0; if (!pr || (count > sizeof(limit_string) - 1)) { return -EINVAL; } if (copy_from_user(limit_string, buffer, count)) { return -EFAULT; } limit_string[count] = '\0'; if (sscanf(limit_string, "%d:%d", &px, &tx) != 2) { printk(KERN_ERR PREFIX "Invalid data format\n"); return -EINVAL; } if (pr->flags.throttling) { if ((tx < 0) || (tx > (pr->throttling.state_count - 1))) { printk(KERN_ERR PREFIX "Invalid tx\n"); return -EINVAL; } pr->limit.user.tx = tx; } result = acpi_processor_apply_limit(pr); return count; } const struct file_operations acpi_processor_limit_fops = { .owner = THIS_MODULE, .open = acpi_processor_limit_open_fs, .read = seq_read, .write = acpi_processor_write_limit, .llseek = seq_lseek, .release = single_release, }; #endif