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393 lines
9.5 KiB
393 lines
9.5 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Intel SpeedStep SMI driver. |
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* |
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* (C) 2003 Hiroshi Miura <[email protected]> |
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*/ |
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/********************************************************************* |
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* SPEEDSTEP - DEFINITIONS * |
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*********************************************************************/ |
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#define pr_fmt(fmt) "cpufreq: " fmt |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/init.h> |
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#include <linux/cpufreq.h> |
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#include <linux/delay.h> |
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#include <linux/io.h> |
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#include <asm/ist.h> |
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#include <asm/cpu_device_id.h> |
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#include "speedstep-lib.h" |
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/* speedstep system management interface port/command. |
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* |
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* These parameters are got from IST-SMI BIOS call. |
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* If user gives it, these are used. |
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* |
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*/ |
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static int smi_port; |
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static int smi_cmd; |
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static unsigned int smi_sig; |
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/* info about the processor */ |
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static enum speedstep_processor speedstep_processor; |
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/* |
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* There are only two frequency states for each processor. Values |
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* are in kHz for the time being. |
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*/ |
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static struct cpufreq_frequency_table speedstep_freqs[] = { |
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{0, SPEEDSTEP_HIGH, 0}, |
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{0, SPEEDSTEP_LOW, 0}, |
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{0, 0, CPUFREQ_TABLE_END}, |
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}; |
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#define GET_SPEEDSTEP_OWNER 0 |
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#define GET_SPEEDSTEP_STATE 1 |
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#define SET_SPEEDSTEP_STATE 2 |
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#define GET_SPEEDSTEP_FREQS 4 |
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/* how often shall the SMI call be tried if it failed, e.g. because |
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* of DMA activity going on? */ |
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#define SMI_TRIES 5 |
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/** |
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* speedstep_smi_ownership |
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*/ |
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static int speedstep_smi_ownership(void) |
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{ |
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u32 command, result, magic, dummy; |
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u32 function = GET_SPEEDSTEP_OWNER; |
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unsigned char magic_data[] = "Copyright (c) 1999 Intel Corporation"; |
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command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); |
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magic = virt_to_phys(magic_data); |
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pr_debug("trying to obtain ownership with command %x at port %x\n", |
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command, smi_port); |
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__asm__ __volatile__( |
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"push %%ebp\n" |
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"out %%al, (%%dx)\n" |
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"pop %%ebp\n" |
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: "=D" (result), |
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"=a" (dummy), "=b" (dummy), "=c" (dummy), "=d" (dummy), |
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"=S" (dummy) |
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: "a" (command), "b" (function), "c" (0), "d" (smi_port), |
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"D" (0), "S" (magic) |
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: "memory" |
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); |
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pr_debug("result is %x\n", result); |
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return result; |
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} |
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/** |
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* speedstep_smi_get_freqs - get SpeedStep preferred & current freq. |
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* @low: the low frequency value is placed here |
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* @high: the high frequency value is placed here |
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* |
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* Only available on later SpeedStep-enabled systems, returns false results or |
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* even hangs [cf. bugme.osdl.org # 1422] on earlier systems. Empirical testing |
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* shows that the latter occurs if !(ist_info.event & 0xFFFF). |
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*/ |
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static int speedstep_smi_get_freqs(unsigned int *low, unsigned int *high) |
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{ |
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u32 command, result = 0, edi, high_mhz, low_mhz, dummy; |
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u32 state = 0; |
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u32 function = GET_SPEEDSTEP_FREQS; |
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if (!(ist_info.event & 0xFFFF)) { |
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pr_debug("bug #1422 -- can't read freqs from BIOS\n"); |
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return -ENODEV; |
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} |
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command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); |
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pr_debug("trying to determine frequencies with command %x at port %x\n", |
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command, smi_port); |
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__asm__ __volatile__( |
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"push %%ebp\n" |
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"out %%al, (%%dx)\n" |
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"pop %%ebp" |
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: "=a" (result), |
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"=b" (high_mhz), |
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"=c" (low_mhz), |
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"=d" (state), "=D" (edi), "=S" (dummy) |
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: "a" (command), |
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"b" (function), |
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"c" (state), |
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"d" (smi_port), "S" (0), "D" (0) |
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); |
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pr_debug("result %x, low_freq %u, high_freq %u\n", |
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result, low_mhz, high_mhz); |
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/* abort if results are obviously incorrect... */ |
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if ((high_mhz + low_mhz) < 600) |
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return -EINVAL; |
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*high = high_mhz * 1000; |
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*low = low_mhz * 1000; |
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return result; |
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} |
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/** |
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* speedstep_set_state - set the SpeedStep state |
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* @state: new processor frequency state (SPEEDSTEP_LOW or SPEEDSTEP_HIGH) |
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* |
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*/ |
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static void speedstep_set_state(unsigned int state) |
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{ |
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unsigned int result = 0, command, new_state, dummy; |
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unsigned long flags; |
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unsigned int function = SET_SPEEDSTEP_STATE; |
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unsigned int retry = 0; |
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if (state > 0x1) |
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return; |
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/* Disable IRQs */ |
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preempt_disable(); |
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local_irq_save(flags); |
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command = (smi_sig & 0xffffff00) | (smi_cmd & 0xff); |
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pr_debug("trying to set frequency to state %u " |
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"with command %x at port %x\n", |
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state, command, smi_port); |
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do { |
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if (retry) { |
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/* |
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* We need to enable interrupts, otherwise the blockage |
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* won't resolve. |
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* |
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* We disable preemption so that other processes don't |
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* run. If other processes were running, they could |
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* submit more DMA requests, making the blockage worse. |
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*/ |
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pr_debug("retry %u, previous result %u, waiting...\n", |
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retry, result); |
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local_irq_enable(); |
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mdelay(retry * 50); |
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local_irq_disable(); |
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} |
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retry++; |
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__asm__ __volatile__( |
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"push %%ebp\n" |
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"out %%al, (%%dx)\n" |
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"pop %%ebp" |
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: "=b" (new_state), "=D" (result), |
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"=c" (dummy), "=a" (dummy), |
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"=d" (dummy), "=S" (dummy) |
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: "a" (command), "b" (function), "c" (state), |
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"d" (smi_port), "S" (0), "D" (0) |
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); |
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} while ((new_state != state) && (retry <= SMI_TRIES)); |
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/* enable IRQs */ |
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local_irq_restore(flags); |
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preempt_enable(); |
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if (new_state == state) |
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pr_debug("change to %u MHz succeeded after %u tries " |
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"with result %u\n", |
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(speedstep_freqs[new_state].frequency / 1000), |
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retry, result); |
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else |
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pr_err("change to state %u failed with new_state %u and result %u\n", |
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state, new_state, result); |
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return; |
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} |
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/** |
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* speedstep_target - set a new CPUFreq policy |
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* @policy: new policy |
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* @index: index of new freq |
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* |
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* Sets a new CPUFreq policy/freq. |
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*/ |
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static int speedstep_target(struct cpufreq_policy *policy, unsigned int index) |
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{ |
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speedstep_set_state(index); |
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return 0; |
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} |
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static int speedstep_cpu_init(struct cpufreq_policy *policy) |
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{ |
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int result; |
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unsigned int *low, *high; |
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/* capability check */ |
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if (policy->cpu != 0) |
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return -ENODEV; |
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result = speedstep_smi_ownership(); |
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if (result) { |
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pr_debug("fails in acquiring ownership of a SMI interface.\n"); |
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return -EINVAL; |
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} |
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/* detect low and high frequency */ |
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low = &speedstep_freqs[SPEEDSTEP_LOW].frequency; |
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high = &speedstep_freqs[SPEEDSTEP_HIGH].frequency; |
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result = speedstep_smi_get_freqs(low, high); |
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if (result) { |
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/* fall back to speedstep_lib.c dection mechanism: |
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* try both states out */ |
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pr_debug("could not detect low and high frequencies " |
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"by SMI call.\n"); |
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result = speedstep_get_freqs(speedstep_processor, |
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low, high, |
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NULL, |
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&speedstep_set_state); |
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if (result) { |
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pr_debug("could not detect two different speeds" |
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" -- aborting.\n"); |
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return result; |
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} else |
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pr_debug("workaround worked.\n"); |
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} |
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policy->freq_table = speedstep_freqs; |
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return 0; |
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} |
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static unsigned int speedstep_get(unsigned int cpu) |
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{ |
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if (cpu) |
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return -ENODEV; |
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return speedstep_get_frequency(speedstep_processor); |
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} |
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static int speedstep_resume(struct cpufreq_policy *policy) |
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{ |
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int result = speedstep_smi_ownership(); |
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if (result) |
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pr_debug("fails in re-acquiring ownership of a SMI interface.\n"); |
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return result; |
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} |
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static struct cpufreq_driver speedstep_driver = { |
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.name = "speedstep-smi", |
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.flags = CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING, |
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.verify = cpufreq_generic_frequency_table_verify, |
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.target_index = speedstep_target, |
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.init = speedstep_cpu_init, |
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.get = speedstep_get, |
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.resume = speedstep_resume, |
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.attr = cpufreq_generic_attr, |
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}; |
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static const struct x86_cpu_id ss_smi_ids[] = { |
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X86_MATCH_VENDOR_FAM_MODEL(INTEL, 6, 0x8, 0), |
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X86_MATCH_VENDOR_FAM_MODEL(INTEL, 6, 0xb, 0), |
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X86_MATCH_VENDOR_FAM_MODEL(INTEL, 15, 0x2, 0), |
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{} |
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}; |
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/** |
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* speedstep_init - initializes the SpeedStep CPUFreq driver |
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* |
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* Initializes the SpeedStep support. Returns -ENODEV on unsupported |
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* BIOS, -EINVAL on problems during initiatization, and zero on |
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* success. |
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*/ |
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static int __init speedstep_init(void) |
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{ |
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if (!x86_match_cpu(ss_smi_ids)) |
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return -ENODEV; |
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speedstep_processor = speedstep_detect_processor(); |
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switch (speedstep_processor) { |
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case SPEEDSTEP_CPU_PIII_T: |
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case SPEEDSTEP_CPU_PIII_C: |
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case SPEEDSTEP_CPU_PIII_C_EARLY: |
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break; |
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default: |
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speedstep_processor = 0; |
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} |
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if (!speedstep_processor) { |
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pr_debug("No supported Intel CPU detected.\n"); |
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return -ENODEV; |
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} |
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pr_debug("signature:0x%.8x, command:0x%.8x, " |
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"event:0x%.8x, perf_level:0x%.8x.\n", |
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ist_info.signature, ist_info.command, |
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ist_info.event, ist_info.perf_level); |
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/* Error if no IST-SMI BIOS or no PARM |
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sig= 'ISGE' aka 'Intel Speedstep Gate E' */ |
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if ((ist_info.signature != 0x47534943) && ( |
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(smi_port == 0) || (smi_cmd == 0))) |
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return -ENODEV; |
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if (smi_sig == 1) |
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smi_sig = 0x47534943; |
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else |
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smi_sig = ist_info.signature; |
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/* setup smi_port from MODLULE_PARM or BIOS */ |
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if ((smi_port > 0xff) || (smi_port < 0)) |
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return -EINVAL; |
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else if (smi_port == 0) |
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smi_port = ist_info.command & 0xff; |
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if ((smi_cmd > 0xff) || (smi_cmd < 0)) |
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return -EINVAL; |
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else if (smi_cmd == 0) |
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smi_cmd = (ist_info.command >> 16) & 0xff; |
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return cpufreq_register_driver(&speedstep_driver); |
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} |
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/** |
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* speedstep_exit - unregisters SpeedStep support |
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* |
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* Unregisters SpeedStep support. |
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*/ |
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static void __exit speedstep_exit(void) |
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{ |
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cpufreq_unregister_driver(&speedstep_driver); |
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} |
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module_param_hw(smi_port, int, ioport, 0444); |
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module_param(smi_cmd, int, 0444); |
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module_param(smi_sig, uint, 0444); |
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MODULE_PARM_DESC(smi_port, "Override the BIOS-given IST port with this value " |
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"-- Intel's default setting is 0xb2"); |
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MODULE_PARM_DESC(smi_cmd, "Override the BIOS-given IST command with this value " |
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"-- Intel's default setting is 0x82"); |
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MODULE_PARM_DESC(smi_sig, "Set to 1 to fake the IST signature when using the " |
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"SMI interface."); |
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MODULE_AUTHOR("Hiroshi Miura"); |
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MODULE_DESCRIPTION("Speedstep driver for IST applet SMI interface."); |
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MODULE_LICENSE("GPL"); |
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module_init(speedstep_init); |
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module_exit(speedstep_exit);
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