summaryrefslogtreecommitdiffstats
path: root/drivers/cpufreq/speedstep-ich.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/cpufreq/speedstep-ich.c')
-rw-r--r--drivers/cpufreq/speedstep-ich.c448
1 files changed, 448 insertions, 0 deletions
diff --git a/drivers/cpufreq/speedstep-ich.c b/drivers/cpufreq/speedstep-ich.c
new file mode 100644
index 000000000000..a748ce782fee
--- /dev/null
+++ b/drivers/cpufreq/speedstep-ich.c
@@ -0,0 +1,448 @@
+/*
+ * (C) 2001 Dave Jones, Arjan van de ven.
+ * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
+ *
+ * Licensed under the terms of the GNU GPL License version 2.
+ * Based upon reverse engineered information, and on Intel documentation
+ * for chipsets ICH2-M and ICH3-M.
+ *
+ * Many thanks to Ducrot Bruno for finding and fixing the last
+ * "missing link" for ICH2-M/ICH3-M support, and to Thomas Winkler
+ * for extensive testing.
+ *
+ * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
+ */
+
+
+/*********************************************************************
+ * SPEEDSTEP - DEFINITIONS *
+ *********************************************************************/
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+#include <linux/pci.h>
+#include <linux/sched.h>
+
+#include "speedstep-lib.h"
+
+
+/* speedstep_chipset:
+ * It is necessary to know which chipset is used. As accesses to
+ * this device occur at various places in this module, we need a
+ * static struct pci_dev * pointing to that device.
+ */
+static struct pci_dev *speedstep_chipset_dev;
+
+
+/* speedstep_processor
+ */
+static enum speedstep_processor speedstep_processor;
+
+static u32 pmbase;
+
+/*
+ * There are only two frequency states for each processor. Values
+ * are in kHz for the time being.
+ */
+static struct cpufreq_frequency_table speedstep_freqs[] = {
+ {SPEEDSTEP_HIGH, 0},
+ {SPEEDSTEP_LOW, 0},
+ {0, CPUFREQ_TABLE_END},
+};
+
+
+/**
+ * speedstep_find_register - read the PMBASE address
+ *
+ * Returns: -ENODEV if no register could be found
+ */
+static int speedstep_find_register(void)
+{
+ if (!speedstep_chipset_dev)
+ return -ENODEV;
+
+ /* get PMBASE */
+ pci_read_config_dword(speedstep_chipset_dev, 0x40, &pmbase);
+ if (!(pmbase & 0x01)) {
+ printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
+ return -ENODEV;
+ }
+
+ pmbase &= 0xFFFFFFFE;
+ if (!pmbase) {
+ printk(KERN_ERR "speedstep-ich: could not find speedstep register\n");
+ return -ENODEV;
+ }
+
+ pr_debug("pmbase is 0x%x\n", pmbase);
+ return 0;
+}
+
+/**
+ * speedstep_set_state - set the SpeedStep state
+ * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH)
+ *
+ * Tries to change the SpeedStep state. Can be called from
+ * smp_call_function_single.
+ */
+static void speedstep_set_state(unsigned int state)
+{
+ u8 pm2_blk;
+ u8 value;
+ unsigned long flags;
+
+ if (state > 0x1)
+ return;
+
+ /* Disable IRQs */
+ local_irq_save(flags);
+
+ /* read state */
+ value = inb(pmbase + 0x50);
+
+ pr_debug("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
+
+ /* write new state */
+ value &= 0xFE;
+ value |= state;
+
+ pr_debug("writing 0x%x to pmbase 0x%x + 0x50\n", value, pmbase);
+
+ /* Disable bus master arbitration */
+ pm2_blk = inb(pmbase + 0x20);
+ pm2_blk |= 0x01;
+ outb(pm2_blk, (pmbase + 0x20));
+
+ /* Actual transition */
+ outb(value, (pmbase + 0x50));
+
+ /* Restore bus master arbitration */
+ pm2_blk &= 0xfe;
+ outb(pm2_blk, (pmbase + 0x20));
+
+ /* check if transition was successful */
+ value = inb(pmbase + 0x50);
+
+ /* Enable IRQs */
+ local_irq_restore(flags);
+
+ pr_debug("read at pmbase 0x%x + 0x50 returned 0x%x\n", pmbase, value);
+
+ if (state == (value & 0x1))
+ pr_debug("change to %u MHz succeeded\n",
+ speedstep_get_frequency(speedstep_processor) / 1000);
+ else
+ printk(KERN_ERR "cpufreq: change failed - I/O error\n");
+
+ return;
+}
+
+/* Wrapper for smp_call_function_single. */
+static void _speedstep_set_state(void *_state)
+{
+ speedstep_set_state(*(unsigned int *)_state);
+}
+
+/**
+ * speedstep_activate - activate SpeedStep control in the chipset
+ *
+ * Tries to activate the SpeedStep status and control registers.
+ * Returns -EINVAL on an unsupported chipset, and zero on success.
+ */
+static int speedstep_activate(void)
+{
+ u16 value = 0;
+
+ if (!speedstep_chipset_dev)
+ return -EINVAL;
+
+ pci_read_config_word(speedstep_chipset_dev, 0x00A0, &value);
+ if (!(value & 0x08)) {
+ value |= 0x08;
+ pr_debug("activating SpeedStep (TM) registers\n");
+ pci_write_config_word(speedstep_chipset_dev, 0x00A0, value);
+ }
+
+ return 0;
+}
+
+
+/**
+ * speedstep_detect_chipset - detect the Southbridge which contains SpeedStep logic
+ *
+ * Detects ICH2-M, ICH3-M and ICH4-M so far. The pci_dev points to
+ * the LPC bridge / PM module which contains all power-management
+ * functions. Returns the SPEEDSTEP_CHIPSET_-number for the detected
+ * chipset, or zero on failure.
+ */
+static unsigned int speedstep_detect_chipset(void)
+{
+ speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+ PCI_DEVICE_ID_INTEL_82801DB_12,
+ PCI_ANY_ID, PCI_ANY_ID,
+ NULL);
+ if (speedstep_chipset_dev)
+ return 4; /* 4-M */
+
+ speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+ PCI_DEVICE_ID_INTEL_82801CA_12,
+ PCI_ANY_ID, PCI_ANY_ID,
+ NULL);
+ if (speedstep_chipset_dev)
+ return 3; /* 3-M */
+
+
+ speedstep_chipset_dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+ PCI_DEVICE_ID_INTEL_82801BA_10,
+ PCI_ANY_ID, PCI_ANY_ID,
+ NULL);
+ if (speedstep_chipset_dev) {
+ /* speedstep.c causes lockups on Dell Inspirons 8000 and
+ * 8100 which use a pretty old revision of the 82815
+ * host brige. Abort on these systems.
+ */
+ static struct pci_dev *hostbridge;
+
+ hostbridge = pci_get_subsys(PCI_VENDOR_ID_INTEL,
+ PCI_DEVICE_ID_INTEL_82815_MC,
+ PCI_ANY_ID, PCI_ANY_ID,
+ NULL);
+
+ if (!hostbridge)
+ return 2; /* 2-M */
+
+ if (hostbridge->revision < 5) {
+ pr_debug("hostbridge does not support speedstep\n");
+ speedstep_chipset_dev = NULL;
+ pci_dev_put(hostbridge);
+ return 0;
+ }
+
+ pci_dev_put(hostbridge);
+ return 2; /* 2-M */
+ }
+
+ return 0;
+}
+
+static void get_freq_data(void *_speed)
+{
+ unsigned int *speed = _speed;
+
+ *speed = speedstep_get_frequency(speedstep_processor);
+}
+
+static unsigned int speedstep_get(unsigned int cpu)
+{
+ unsigned int speed;
+
+ /* You're supposed to ensure CPU is online. */
+ if (smp_call_function_single(cpu, get_freq_data, &speed, 1) != 0)
+ BUG();
+
+ pr_debug("detected %u kHz as current frequency\n", speed);
+ return speed;
+}
+
+/**
+ * speedstep_target - set a new CPUFreq policy
+ * @policy: new policy
+ * @target_freq: the target frequency
+ * @relation: how that frequency relates to achieved frequency
+ * (CPUFREQ_RELATION_L or CPUFREQ_RELATION_H)
+ *
+ * Sets a new CPUFreq policy.
+ */
+static int speedstep_target(struct cpufreq_policy *policy,
+ unsigned int target_freq,
+ unsigned int relation)
+{
+ unsigned int newstate = 0, policy_cpu;
+ struct cpufreq_freqs freqs;
+ int i;
+
+ if (cpufreq_frequency_table_target(policy, &speedstep_freqs[0],
+ target_freq, relation, &newstate))
+ return -EINVAL;
+
+ policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
+ freqs.old = speedstep_get(policy_cpu);
+ freqs.new = speedstep_freqs[newstate].frequency;
+ freqs.cpu = policy->cpu;
+
+ pr_debug("transiting from %u to %u kHz\n", freqs.old, freqs.new);
+
+ /* no transition necessary */
+ if (freqs.old == freqs.new)
+ return 0;
+
+ for_each_cpu(i, policy->cpus) {
+ freqs.cpu = i;
+ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+ }
+
+ smp_call_function_single(policy_cpu, _speedstep_set_state, &newstate,
+ true);
+
+ for_each_cpu(i, policy->cpus) {
+ freqs.cpu = i;
+ cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+ }
+
+ return 0;
+}
+
+
+/**
+ * speedstep_verify - verifies a new CPUFreq policy
+ * @policy: new policy
+ *
+ * Limit must be within speedstep_low_freq and speedstep_high_freq, with
+ * at least one border included.
+ */
+static int speedstep_verify(struct cpufreq_policy *policy)
+{
+ return cpufreq_frequency_table_verify(policy, &speedstep_freqs[0]);
+}
+
+struct get_freqs {
+ struct cpufreq_policy *policy;
+ int ret;
+};
+
+static void get_freqs_on_cpu(void *_get_freqs)
+{
+ struct get_freqs *get_freqs = _get_freqs;
+
+ get_freqs->ret =
+ speedstep_get_freqs(speedstep_processor,
+ &speedstep_freqs[SPEEDSTEP_LOW].frequency,
+ &speedstep_freqs[SPEEDSTEP_HIGH].frequency,
+ &get_freqs->policy->cpuinfo.transition_latency,
+ &speedstep_set_state);
+}
+
+static int speedstep_cpu_init(struct cpufreq_policy *policy)
+{
+ int result;
+ unsigned int policy_cpu, speed;
+ struct get_freqs gf;
+
+ /* only run on CPU to be set, or on its sibling */
+#ifdef CONFIG_SMP
+ cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
+#endif
+ policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
+
+ /* detect low and high frequency and transition latency */
+ gf.policy = policy;
+ smp_call_function_single(policy_cpu, get_freqs_on_cpu, &gf, 1);
+ if (gf.ret)
+ return gf.ret;
+
+ /* get current speed setting */
+ speed = speedstep_get(policy_cpu);
+ if (!speed)
+ return -EIO;
+
+ pr_debug("currently at %s speed setting - %i MHz\n",
+ (speed == speedstep_freqs[SPEEDSTEP_LOW].frequency)
+ ? "low" : "high",
+ (speed / 1000));
+
+ /* cpuinfo and default policy values */
+ policy->cur = speed;
+
+ result = cpufreq_frequency_table_cpuinfo(policy, speedstep_freqs);
+ if (result)
+ return result;
+
+ cpufreq_frequency_table_get_attr(speedstep_freqs, policy->cpu);
+
+ return 0;
+}
+
+
+static int speedstep_cpu_exit(struct cpufreq_policy *policy)
+{
+ cpufreq_frequency_table_put_attr(policy->cpu);
+ return 0;
+}
+
+static struct freq_attr *speedstep_attr[] = {
+ &cpufreq_freq_attr_scaling_available_freqs,
+ NULL,
+};
+
+
+static struct cpufreq_driver speedstep_driver = {
+ .name = "speedstep-ich",
+ .verify = speedstep_verify,
+ .target = speedstep_target,
+ .init = speedstep_cpu_init,
+ .exit = speedstep_cpu_exit,
+ .get = speedstep_get,
+ .owner = THIS_MODULE,
+ .attr = speedstep_attr,
+};
+
+
+/**
+ * speedstep_init - initializes the SpeedStep CPUFreq driver
+ *
+ * Initializes the SpeedStep support. Returns -ENODEV on unsupported
+ * devices, -EINVAL on problems during initiatization, and zero on
+ * success.
+ */
+static int __init speedstep_init(void)
+{
+ /* detect processor */
+ speedstep_processor = speedstep_detect_processor();
+ if (!speedstep_processor) {
+ pr_debug("Intel(R) SpeedStep(TM) capable processor "
+ "not found\n");
+ return -ENODEV;
+ }
+
+ /* detect chipset */
+ if (!speedstep_detect_chipset()) {
+ pr_debug("Intel(R) SpeedStep(TM) for this chipset not "
+ "(yet) available.\n");
+ return -ENODEV;
+ }
+
+ /* activate speedstep support */
+ if (speedstep_activate()) {
+ pci_dev_put(speedstep_chipset_dev);
+ return -EINVAL;
+ }
+
+ if (speedstep_find_register())
+ return -ENODEV;
+
+ return cpufreq_register_driver(&speedstep_driver);
+}
+
+
+/**
+ * speedstep_exit - unregisters SpeedStep support
+ *
+ * Unregisters SpeedStep support.
+ */
+static void __exit speedstep_exit(void)
+{
+ pci_dev_put(speedstep_chipset_dev);
+ cpufreq_unregister_driver(&speedstep_driver);
+}
+
+
+MODULE_AUTHOR("Dave Jones <davej@redhat.com>, "
+ "Dominik Brodowski <linux@brodo.de>");
+MODULE_DESCRIPTION("Speedstep driver for Intel mobile processors on chipsets "
+ "with ICH-M southbridges.");
+MODULE_LICENSE("GPL");
+
+module_init(speedstep_init);
+module_exit(speedstep_exit);