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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/acpi/processor_throttling.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/acpi/processor_throttling.c')
-rw-r--r-- | drivers/acpi/processor_throttling.c | 351 |
1 files changed, 351 insertions, 0 deletions
diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c new file mode 100644 index 0000000..be9f569 --- /dev/null +++ b/drivers/acpi/processor_throttling.c @@ -0,0 +1,351 @@ +/* + * processor_throttling.c - Throttling 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 <asm/io.h> +#include <asm/uaccess.h> + +#include <acpi/acpi_bus.h> +#include <acpi/processor.h> + +#define ACPI_PROCESSOR_COMPONENT 0x01000000 +#define ACPI_PROCESSOR_CLASS "processor" +#define ACPI_PROCESSOR_DRIVER_NAME "ACPI Processor Driver" +#define _COMPONENT ACPI_PROCESSOR_COMPONENT +ACPI_MODULE_NAME ("acpi_processor") + + +/* -------------------------------------------------------------------------- + Throttling Control + -------------------------------------------------------------------------- */ + +static int +acpi_processor_get_throttling ( + struct acpi_processor *pr) +{ + int state = 0; + u32 value = 0; + u32 duty_mask = 0; + u32 duty_value = 0; + + ACPI_FUNCTION_TRACE("acpi_processor_get_throttling"); + + if (!pr) + return_VALUE(-EINVAL); + + if (!pr->flags.throttling) + return_VALUE(-ENODEV); + + pr->throttling.state = 0; + + duty_mask = pr->throttling.state_count - 1; + + duty_mask <<= pr->throttling.duty_offset; + + local_irq_disable(); + + value = inl(pr->throttling.address); + + /* + * Compute the current throttling state when throttling is enabled + * (bit 4 is on). + */ + if (value & 0x10) { + duty_value = value & duty_mask; + duty_value >>= pr->throttling.duty_offset; + + if (duty_value) + state = pr->throttling.state_count-duty_value; + } + + pr->throttling.state = state; + + local_irq_enable(); + + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "Throttling state is T%d (%d%% throttling applied)\n", + state, pr->throttling.states[state].performance)); + + return_VALUE(0); +} + + +int acpi_processor_set_throttling ( + struct acpi_processor *pr, + int state) +{ + u32 value = 0; + u32 duty_mask = 0; + u32 duty_value = 0; + + ACPI_FUNCTION_TRACE("acpi_processor_set_throttling"); + + if (!pr) + return_VALUE(-EINVAL); + + if ((state < 0) || (state > (pr->throttling.state_count - 1))) + return_VALUE(-EINVAL); + + if (!pr->flags.throttling) + return_VALUE(-ENODEV); + + if (state == pr->throttling.state) + return_VALUE(0); + + /* + * Calculate the duty_value and duty_mask. + */ + if (state) { + duty_value = pr->throttling.state_count - state; + + duty_value <<= pr->throttling.duty_offset; + + /* Used to clear all duty_value bits */ + duty_mask = pr->throttling.state_count - 1; + + duty_mask <<= acpi_fadt.duty_offset; + duty_mask = ~duty_mask; + } + + local_irq_disable(); + + /* + * Disable throttling by writing a 0 to bit 4. Note that we must + * turn it off before you can change the duty_value. + */ + value = inl(pr->throttling.address); + if (value & 0x10) { + value &= 0xFFFFFFEF; + outl(value, pr->throttling.address); + } + + /* + * Write the new duty_value and then enable throttling. Note + * that a state value of 0 leaves throttling disabled. + */ + if (state) { + value &= duty_mask; + value |= duty_value; + outl(value, pr->throttling.address); + + value |= 0x00000010; + outl(value, pr->throttling.address); + } + + pr->throttling.state = state; + + local_irq_enable(); + + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "Throttling state set to T%d (%d%%)\n", state, + (pr->throttling.states[state].performance?pr->throttling.states[state].performance/10:0))); + + return_VALUE(0); +} + + +int +acpi_processor_get_throttling_info ( + struct acpi_processor *pr) +{ + int result = 0; + int step = 0; + int i = 0; + + ACPI_FUNCTION_TRACE("acpi_processor_get_throttling_info"); + + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "pblk_address[0x%08x] duty_offset[%d] duty_width[%d]\n", + pr->throttling.address, + pr->throttling.duty_offset, + pr->throttling.duty_width)); + + if (!pr) + return_VALUE(-EINVAL); + + /* TBD: Support ACPI 2.0 objects */ + + if (!pr->throttling.address) { + ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling register\n")); + return_VALUE(0); + } + else if (!pr->throttling.duty_width) { + ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No throttling states\n")); + return_VALUE(0); + } + /* TBD: Support duty_cycle values that span bit 4. */ + else if ((pr->throttling.duty_offset + + pr->throttling.duty_width) > 4) { + ACPI_DEBUG_PRINT((ACPI_DB_WARN, "duty_cycle spans bit 4\n")); + return_VALUE(0); + } + + /* + * PIIX4 Errata: We don't support throttling on the original PIIX4. + * This shouldn't be an issue as few (if any) mobile systems ever + * used this part. + */ + if (errata.piix4.throttle) { + ACPI_DEBUG_PRINT((ACPI_DB_INFO, + "Throttling not supported on PIIX4 A- or B-step\n")); + return_VALUE(0); + } + + pr->throttling.state_count = 1 << acpi_fadt.duty_width; + + /* + * Compute state values. Note that throttling displays a linear power/ + * performance relationship (at 50% performance the CPU will consume + * 50% power). Values are in 1/10th of a percent to preserve accuracy. + */ + + step = (1000 / pr->throttling.state_count); + + for (i=0; i<pr->throttling.state_count; i++) { + pr->throttling.states[i].performance = step * i; + pr->throttling.states[i].power = step * i; + } + + ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found %d throttling states\n", + pr->throttling.state_count)); + + pr->flags.throttling = 1; + + /* + * Disable throttling (if enabled). We'll let subsequent policy (e.g. + * thermal) decide to lower performance if it so chooses, but for now + * we'll crank up the speed. + */ + + result = acpi_processor_get_throttling(pr); + if (result) + goto end; + + if (pr->throttling.state) { + ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Disabling throttling (was T%d)\n", + pr->throttling.state)); + result = acpi_processor_set_throttling(pr, 0); + if (result) + goto end; + } + +end: + if (result) + pr->flags.throttling = 0; + + return_VALUE(result); +} + + +/* proc interface */ + +static int acpi_processor_throttling_seq_show(struct seq_file *seq, void *offset) +{ + struct acpi_processor *pr = (struct acpi_processor *)seq->private; + int i = 0; + int result = 0; + + ACPI_FUNCTION_TRACE("acpi_processor_throttling_seq_show"); + + if (!pr) + goto end; + + if (!(pr->throttling.state_count > 0)) { + seq_puts(seq, "<not supported>\n"); + goto end; + } + + result = acpi_processor_get_throttling(pr); + + if (result) { + seq_puts(seq, "Could not determine current throttling state.\n"); + goto end; + } + + seq_printf(seq, "state count: %d\n" + "active state: T%d\n", + pr->throttling.state_count, + pr->throttling.state); + + seq_puts(seq, "states:\n"); + for (i = 0; i < pr->throttling.state_count; i++) + seq_printf(seq, " %cT%d: %02d%%\n", + (i == pr->throttling.state?'*':' '), i, + (pr->throttling.states[i].performance?pr->throttling.states[i].performance/10:0)); + +end: + return_VALUE(0); +} + +static int acpi_processor_throttling_open_fs(struct inode *inode, struct file *file) +{ + return single_open(file, acpi_processor_throttling_seq_show, + PDE(inode)->data); +} + +ssize_t acpi_processor_write_throttling ( + struct file *file, + const char __user *buffer, + size_t count, + loff_t *data) +{ + int result = 0; + struct seq_file *m = (struct seq_file *)file->private_data; + struct acpi_processor *pr = (struct acpi_processor *)m->private; + char state_string[12] = {'\0'}; + + ACPI_FUNCTION_TRACE("acpi_processor_write_throttling"); + + if (!pr || (count > sizeof(state_string) - 1)) + return_VALUE(-EINVAL); + + if (copy_from_user(state_string, buffer, count)) + return_VALUE(-EFAULT); + + state_string[count] = '\0'; + + result = acpi_processor_set_throttling(pr, + simple_strtoul(state_string, NULL, 0)); + if (result) + return_VALUE(result); + + return_VALUE(count); +} + +struct file_operations acpi_processor_throttling_fops = { + .open = acpi_processor_throttling_open_fs, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; |