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 000000000000..be9f569d39d3
--- /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,
+};