diff options
Diffstat (limited to '')
| -rw-r--r-- | drivers/cpufreq/speedstep-ich.c | 386 |
1 files changed, 386 insertions, 0 deletions
diff --git a/drivers/cpufreq/speedstep-ich.c b/drivers/cpufreq/speedstep-ich.c new file mode 100644 index 0000000000..f2076d72bf --- /dev/null +++ b/drivers/cpufreq/speedstep-ich.c @@ -0,0 +1,386 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * (C) 2001 Dave Jones, Arjan van de ven. + * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de> + * + * 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 * + *********************************************************************/ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#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)) { + pr_err("could not find speedstep register\n"); + return -ENODEV; + } + + pmbase &= 0xFFFFFFFE; + if (!pmbase) { + pr_err("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 + pr_err("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. + */ + 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. */ + BUG_ON(smp_call_function_single(cpu, get_freq_data, &speed, 1)); + + 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, topology_sibling_cpumask(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; + + policy->freq_table = speedstep_freqs; + + return 0; +} + + +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_MATCH_VENDOR_FAM_MODEL(INTEL, 6, 0x8, 0), + X86_MATCH_VENDOR_FAM_MODEL(INTEL, 6, 0xb, 0), + X86_MATCH_VENDOR_FAM_MODEL(INTEL, 15, 0x2, 0), + {} +}; + +/** + * 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); |