--- /dev/null
+/*
+ * (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 <asm/cpu_device_id.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[] = {
+ {0, SPEEDSTEP_HIGH, 0},
+ {0, SPEEDSTEP_LOW, 0},
+ {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 bridge. 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
+ * @index: index of target frequency
+ *
+ * Sets a new CPUFreq policy.
+ */
+static int speedstep_target(struct cpufreq_policy *policy, unsigned int index)
+{
+ unsigned int policy_cpu;
+
+ policy_cpu = cpumask_any_and(policy->cpus, cpu_online_mask);
+
+ smp_call_function_single(policy_cpu, _speedstep_set_state, &index,
+ true);
+
+ return 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)
+{
+ unsigned int policy_cpu;
+ 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;
+
+ return cpufreq_table_validate_and_show(policy, speedstep_freqs);
+}
+
+
+static struct cpufreq_driver speedstep_driver = {
+ .name = "speedstep-ich",
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = speedstep_target,
+ .init = speedstep_cpu_init,
+ .get = speedstep_get,
+ .attr = cpufreq_generic_attr,
+};
+
+static const struct x86_cpu_id ss_smi_ids[] = {
+ { X86_VENDOR_INTEL, 6, 0xb, },
+ { X86_VENDOR_INTEL, 6, 0x8, },
+ { X86_VENDOR_INTEL, 15, 2 },
+ {}
+};
+#if 0
+/* Autoload or not? Do not for now. */
+MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids);
+#endif
+
+/**
+ * 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)
+{
+ if (!x86_match_cpu(ss_smi_ids))
+ return -ENODEV;
+
+ /* 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, 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);
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