/* * Intel SpeedStep SMI driver. * * (C) 2003 Hiroshi Miura <miura@da-cha.org> * * Licensed under the terms of the GNU GPL License version 2. * */ /********************************************************************* * SPEEDSTEP - DEFINITIONS * *********************************************************************/ #include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/init.h> #include <linux/cpufreq.h> #include <linux/delay.h> #include <linux/io.h> #include <asm/ist.h> #include <asm/cpu_device_id.h> #include "speedstep-lib.h" /* speedstep system management interface port/command. * * These parameters are got from IST-SMI BIOS call. * If user gives it, these are used. * */ static int smi_port; static int smi_cmd; static unsigned int smi_sig; /* info about the processor */ static enum speedstep_processor speedstep_processor; /* * 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}, }; #define GET_SPEEDSTEP_OWNER 0 #define GET_SPEEDSTEP_STATE 1 #define SET_SPEEDSTEP_STATE 2 #define GET_SPEEDSTEP_FREQS 4 /* how often shall the SMI call be tried if it failed, e.g. because * of DMA activity going on? */ #define SMI_TRIES 5 /** * speedstep_smi_ownership */ static int speedstep_smi_ownership(void) { u32 command, result, magic, dummy; u32 function = GET_SPEEDSTEP_OWNER; unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation"; command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); magic = virt_to_phys(magic_data); pr_debug("trying to obtain ownership with command %x at port %x\n", command, smi_port); __asm__ __volatile__( "push %%ebp\n" "out %%al, (%%dx)\n" "pop %%ebp\n" : "=D" (result), "=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy), "=S" (dummy) : "a" (command), "b" (function), "c" (0), "d" (smi_port), "D" (0), "S" (magic) : "memory" ); pr_debug("result is %x\n", result); return result; } /** * speedstep_smi_get_freqs - get SpeedStep preferred & current freq. * @low: the low frequency value is placed here * @high: the high frequency value is placed here * * Only available on later SpeedStep-enabled systems, returns false results or * even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing * shows that the latter occurs if !(ist_info.event & 0xFFFF). */ static int speedstep_smi_get_freqs(unsigned int *low, unsigned int *high) { u32 command, result = 0, edi, high_mhz, low_mhz, dummy; u32 state = 0; u32 function = GET_SPEEDSTEP_FREQS; if (!(ist_info.event & 0xFFFF)) { pr_debug("bug #1422 -- can't read freqs from BIOS\n"); return -ENODEV; } command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); pr_debug("trying to determine frequencies with command %x at port %x\n", command, smi_port); __asm__ __volatile__( "push %%ebp\n" "out %%al, (%%dx)\n" "pop %%ebp" : "=a" (result), "=b" (high_mhz), "=c" (low_mhz), "=d" (state), "=D" (edi), "=S" (dummy) : "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0), "D" (0) ); pr_debug("result %x, low_freq %u, high_freq %u\n", result, low_mhz, high_mhz); /* abort if results are obviously incorrect... */ if ((high_mhz + low_mhz) < 600) return -EINVAL; *high = high_mhz * 1000; *low = low_mhz * 1000; return result; } /** * speedstep_set_state - set the SpeedStep state * @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH) * */ static void speedstep_set_state(unsigned int state) { unsigned int result = 0, command, new_state, dummy; unsigned long flags; unsigned int function = SET_SPEEDSTEP_STATE; unsigned int retry = 0; if (state > 0x1) return; /* Disable IRQs */ preempt_disable(); local_irq_save(flags); command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); pr_debug("trying to set frequency to state %u " "with command %x at port %x\n", state, command, smi_port); do { if (retry) { /* * We need to enable interrupts, otherwise the blockage * won't resolve. * * We disable preemption so that other processes don't * run. If other processes were running, they could * submit more DMA requests, making the blockage worse. */ pr_debug("retry %u, previous result %u, waiting...\n", retry, result); local_irq_enable(); mdelay(retry * 50); local_irq_disable(); } retry++; __asm__ __volatile__( "push %%ebp\n" "out %%al, (%%dx)\n" "pop %%ebp" : "=b" (new_state), "=D" (result), "=c" (dummy), "=a" (dummy), "=d" (dummy), "=S" (dummy) : "a" (command), "b" (function), "c" (state), "d" (smi_port), "S" (0), "D" (0) ); } while ((new_state != state) && (retry <= SMI_TRIES)); /* enable IRQs */ local_irq_restore(flags); preempt_enable(); if (new_state == state) pr_debug("change to %u MHz succeeded after %u tries " "with result %u\n", (speedstep_freqs[new_state].frequency / 1000), retry, result); else printk(KERN_ERR "cpufreq: change to state %u " "failed with new_state %u and result %u\n", state, new_state, result); return; } /** * speedstep_target - set a new CPUFreq policy * @policy: new policy * @index: index of new freq * * Sets a new CPUFreq policy/freq. */ static int speedstep_target(struct cpufreq_policy *policy, unsigned int index) { speedstep_set_state(index); return 0; } static int speedstep_cpu_init(struct cpufreq_policy *policy) { int result; unsigned int *low, *high; /* capability check */ if (policy->cpu != 0) return -ENODEV; result = speedstep_smi_ownership(); if (result) { pr_debug("fails in acquiring ownership of a SMI interface.\n"); return -EINVAL; } /* detect low and high frequency */ low = &speedstep_freqs[SPEEDSTEP_LOW].frequency; high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency; result = speedstep_smi_get_freqs(low, high); if (result) { /* fall back to speedstep_lib.c dection mechanism: * try both states out */ pr_debug("could not detect low and high frequencies " "by SMI call.\n"); result = speedstep_get_freqs(speedstep_processor, low, high, NULL, &speedstep_set_state); if (result) { pr_debug("could not detect two different speeds" " -- aborting.\n"); return result; } else pr_debug("workaround worked.\n"); } policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; return cpufreq_table_validate_and_show(policy, speedstep_freqs); } static unsigned int speedstep_get(unsigned int cpu) { if (cpu) return -ENODEV; return speedstep_get_frequency(speedstep_processor); } static int speedstep_resume(struct cpufreq_policy *policy) { int result = speedstep_smi_ownership(); if (result) pr_debug("fails in re-acquiring ownership of a SMI interface.\n"); return result; } static struct cpufreq_driver speedstep_driver = { .name = "speedstep-smi", .verify = cpufreq_generic_frequency_table_verify, .target_index = speedstep_target, .init = speedstep_cpu_init, .get = speedstep_get, .resume = speedstep_resume, .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 /* Not auto loaded currently */ MODULE_DEVICE_TABLE(x86cpu, ss_smi_ids); #endif /** * speedstep_init - initializes the SpeedStep CPUFreq driver * * Initializes the SpeedStep support. Returns -ENODEV on unsupported * BIOS, -EINVAL on problems during initiatization, and zero on * success. */ static int __init speedstep_init(void) { if (!x86_match_cpu(ss_smi_ids)) return -ENODEV; speedstep_processor = speedstep_detect_processor(); switch (speedstep_processor) { case SPEEDSTEP_CPU_PIII_T: case SPEEDSTEP_CPU_PIII_C: case SPEEDSTEP_CPU_PIII_C_EARLY: break; default: speedstep_processor = 0; } if (!speedstep_processor) { pr_debug("No supported Intel CPU detected.\n"); return -ENODEV; } pr_debug("signature:0x%.8x, command:0x%.8x, " "event:0x%.8x, perf_level:0x%.8x.\n", ist_info.signature, ist_info.command, ist_info.event, ist_info.perf_level); /* Error if no IST-SMI BIOS or no PARM sig= 'ISGE' aka 'Intel Speedstep Gate E' */ if ((ist_info.signature != 0x47534943) && ( (smi_port == 0) || (smi_cmd == 0))) return -ENODEV; if (smi_sig == 1) smi_sig = 0x47534943; else smi_sig = ist_info.signature; /* setup smi_port from MODLULE_PARM or BIOS */ if ((smi_port > 0xff) || (smi_port < 0)) return -EINVAL; else if (smi_port == 0) smi_port = ist_info.command & 0xff; if ((smi_cmd > 0xff) || (smi_cmd < 0)) return -EINVAL; else if (smi_cmd == 0) smi_cmd = (ist_info.command >> 16) & 0xff; return cpufreq_register_driver(&speedstep_driver); } /** * speedstep_exit - unregisters SpeedStep support * * Unregisters SpeedStep support. */ static void __exit speedstep_exit(void) { cpufreq_unregister_driver(&speedstep_driver); } module_param(smi_port, int, 0444); module_param(smi_cmd, int, 0444); module_param(smi_sig, uint, 0444); MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value " "-- Intel's default setting is 0xb2"); MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value " "-- Intel's default setting is 0x82"); MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the " "SMI interface."); MODULE_AUTHOR("Hiroshi Miura"); MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface."); MODULE_LICENSE("GPL"); module_init(speedstep_init); module_exit(speedstep_exit);