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-rw-r--r--drivers/cpufreq/speedstep-lib.c479
1 files changed, 479 insertions, 0 deletions
diff --git a/drivers/cpufreq/speedstep-lib.c b/drivers/cpufreq/speedstep-lib.c
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index 0000000000..0b66df4ed5
--- /dev/null
+++ b/drivers/cpufreq/speedstep-lib.c
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+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
+ *
+ * Library for common functions for Intel SpeedStep v.1 and v.2 support
+ *
+ * BIG FAT DISCLAIMER: Work in progress code. Possibly *dangerous*
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+
+#include <asm/msr.h>
+#include <asm/tsc.h>
+#include "speedstep-lib.h"
+
+#define PFX "speedstep-lib: "
+
+#ifdef CONFIG_X86_SPEEDSTEP_RELAXED_CAP_CHECK
+static int relaxed_check;
+#else
+#define relaxed_check 0
+#endif
+
+/*********************************************************************
+ * GET PROCESSOR CORE SPEED IN KHZ *
+ *********************************************************************/
+
+static unsigned int pentium3_get_frequency(enum speedstep_processor processor)
+{
+ /* See table 14 of p3_ds.pdf and table 22 of 29834003.pdf */
+ static const struct {
+ unsigned int ratio; /* Frequency Multiplier (x10) */
+ u8 bitmap; /* power on configuration bits
+ [27, 25:22] (in MSR 0x2a) */
+ } msr_decode_mult[] = {
+ { 30, 0x01 },
+ { 35, 0x05 },
+ { 40, 0x02 },
+ { 45, 0x06 },
+ { 50, 0x00 },
+ { 55, 0x04 },
+ { 60, 0x0b },
+ { 65, 0x0f },
+ { 70, 0x09 },
+ { 75, 0x0d },
+ { 80, 0x0a },
+ { 85, 0x26 },
+ { 90, 0x20 },
+ { 100, 0x2b },
+ { 0, 0xff } /* error or unknown value */
+ };
+
+ /* PIII(-M) FSB settings: see table b1-b of 24547206.pdf */
+ static const struct {
+ unsigned int value; /* Front Side Bus speed in MHz */
+ u8 bitmap; /* power on configuration bits [18: 19]
+ (in MSR 0x2a) */
+ } msr_decode_fsb[] = {
+ { 66, 0x0 },
+ { 100, 0x2 },
+ { 133, 0x1 },
+ { 0, 0xff}
+ };
+
+ u32 msr_lo, msr_tmp;
+ int i = 0, j = 0;
+
+ /* read MSR 0x2a - we only need the low 32 bits */
+ rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp);
+ pr_debug("P3 - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", msr_lo, msr_tmp);
+ msr_tmp = msr_lo;
+
+ /* decode the FSB */
+ msr_tmp &= 0x00c0000;
+ msr_tmp >>= 18;
+ while (msr_tmp != msr_decode_fsb[i].bitmap) {
+ if (msr_decode_fsb[i].bitmap == 0xff)
+ return 0;
+ i++;
+ }
+
+ /* decode the multiplier */
+ if (processor == SPEEDSTEP_CPU_PIII_C_EARLY) {
+ pr_debug("workaround for early PIIIs\n");
+ msr_lo &= 0x03c00000;
+ } else
+ msr_lo &= 0x0bc00000;
+ msr_lo >>= 22;
+ while (msr_lo != msr_decode_mult[j].bitmap) {
+ if (msr_decode_mult[j].bitmap == 0xff)
+ return 0;
+ j++;
+ }
+
+ pr_debug("speed is %u\n",
+ (msr_decode_mult[j].ratio * msr_decode_fsb[i].value * 100));
+
+ return msr_decode_mult[j].ratio * msr_decode_fsb[i].value * 100;
+}
+
+
+static unsigned int pentiumM_get_frequency(void)
+{
+ u32 msr_lo, msr_tmp;
+
+ rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp);
+ pr_debug("PM - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n", msr_lo, msr_tmp);
+
+ /* see table B-2 of 24547212.pdf */
+ if (msr_lo & 0x00040000) {
+ printk(KERN_DEBUG PFX "PM - invalid FSB: 0x%x 0x%x\n",
+ msr_lo, msr_tmp);
+ return 0;
+ }
+
+ msr_tmp = (msr_lo >> 22) & 0x1f;
+ pr_debug("bits 22-26 are 0x%x, speed is %u\n",
+ msr_tmp, (msr_tmp * 100 * 1000));
+
+ return msr_tmp * 100 * 1000;
+}
+
+static unsigned int pentium_core_get_frequency(void)
+{
+ u32 fsb = 0;
+ u32 msr_lo, msr_tmp;
+ int ret;
+
+ rdmsr(MSR_FSB_FREQ, msr_lo, msr_tmp);
+ /* see table B-2 of 25366920.pdf */
+ switch (msr_lo & 0x07) {
+ case 5:
+ fsb = 100000;
+ break;
+ case 1:
+ fsb = 133333;
+ break;
+ case 3:
+ fsb = 166667;
+ break;
+ case 2:
+ fsb = 200000;
+ break;
+ case 0:
+ fsb = 266667;
+ break;
+ case 4:
+ fsb = 333333;
+ break;
+ default:
+ pr_err("PCORE - MSR_FSB_FREQ undefined value\n");
+ }
+
+ rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp);
+ pr_debug("PCORE - MSR_IA32_EBL_CR_POWERON: 0x%x 0x%x\n",
+ msr_lo, msr_tmp);
+
+ msr_tmp = (msr_lo >> 22) & 0x1f;
+ pr_debug("bits 22-26 are 0x%x, speed is %u\n",
+ msr_tmp, (msr_tmp * fsb));
+
+ ret = (msr_tmp * fsb);
+ return ret;
+}
+
+
+static unsigned int pentium4_get_frequency(void)
+{
+ struct cpuinfo_x86 *c = &boot_cpu_data;
+ u32 msr_lo, msr_hi, mult;
+ unsigned int fsb = 0;
+ unsigned int ret;
+ u8 fsb_code;
+
+ /* Pentium 4 Model 0 and 1 do not have the Core Clock Frequency
+ * to System Bus Frequency Ratio Field in the Processor Frequency
+ * Configuration Register of the MSR. Therefore the current
+ * frequency cannot be calculated and has to be measured.
+ */
+ if (c->x86_model < 2)
+ return cpu_khz;
+
+ rdmsr(0x2c, msr_lo, msr_hi);
+
+ pr_debug("P4 - MSR_EBC_FREQUENCY_ID: 0x%x 0x%x\n", msr_lo, msr_hi);
+
+ /* decode the FSB: see IA-32 Intel (C) Architecture Software
+ * Developer's Manual, Volume 3: System Prgramming Guide,
+ * revision #12 in Table B-1: MSRs in the Pentium 4 and
+ * Intel Xeon Processors, on page B-4 and B-5.
+ */
+ fsb_code = (msr_lo >> 16) & 0x7;
+ switch (fsb_code) {
+ case 0:
+ fsb = 100 * 1000;
+ break;
+ case 1:
+ fsb = 13333 * 10;
+ break;
+ case 2:
+ fsb = 200 * 1000;
+ break;
+ }
+
+ if (!fsb)
+ printk(KERN_DEBUG PFX "couldn't detect FSB speed. "
+ "Please send an e-mail to <linux@brodo.de>\n");
+
+ /* Multiplier. */
+ mult = msr_lo >> 24;
+
+ pr_debug("P4 - FSB %u kHz; Multiplier %u; Speed %u kHz\n",
+ fsb, mult, (fsb * mult));
+
+ ret = (fsb * mult);
+ return ret;
+}
+
+
+/* Warning: may get called from smp_call_function_single. */
+unsigned int speedstep_get_frequency(enum speedstep_processor processor)
+{
+ switch (processor) {
+ case SPEEDSTEP_CPU_PCORE:
+ return pentium_core_get_frequency();
+ case SPEEDSTEP_CPU_PM:
+ return pentiumM_get_frequency();
+ case SPEEDSTEP_CPU_P4D:
+ case SPEEDSTEP_CPU_P4M:
+ return pentium4_get_frequency();
+ case SPEEDSTEP_CPU_PIII_T:
+ case SPEEDSTEP_CPU_PIII_C:
+ case SPEEDSTEP_CPU_PIII_C_EARLY:
+ return pentium3_get_frequency(processor);
+ default:
+ return 0;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(speedstep_get_frequency);
+
+
+/*********************************************************************
+ * DETECT SPEEDSTEP-CAPABLE PROCESSOR *
+ *********************************************************************/
+
+/* Keep in sync with the x86_cpu_id tables in the different modules */
+enum speedstep_processor speedstep_detect_processor(void)
+{
+ struct cpuinfo_x86 *c = &cpu_data(0);
+ u32 ebx, msr_lo, msr_hi;
+
+ pr_debug("x86: %x, model: %x\n", c->x86, c->x86_model);
+
+ if ((c->x86_vendor != X86_VENDOR_INTEL) ||
+ ((c->x86 != 6) && (c->x86 != 0xF)))
+ return 0;
+
+ if (c->x86 == 0xF) {
+ /* Intel Mobile Pentium 4-M
+ * or Intel Mobile Pentium 4 with 533 MHz FSB */
+ if (c->x86_model != 2)
+ return 0;
+
+ ebx = cpuid_ebx(0x00000001);
+ ebx &= 0x000000FF;
+
+ pr_debug("ebx value is %x, x86_stepping is %x\n", ebx, c->x86_stepping);
+
+ switch (c->x86_stepping) {
+ case 4:
+ /*
+ * B-stepping [M-P4-M]
+ * sample has ebx = 0x0f, production has 0x0e.
+ */
+ if ((ebx == 0x0e) || (ebx == 0x0f))
+ return SPEEDSTEP_CPU_P4M;
+ break;
+ case 7:
+ /*
+ * C-stepping [M-P4-M]
+ * needs to have ebx=0x0e, else it's a celeron:
+ * cf. 25130917.pdf / page 7, footnote 5 even
+ * though 25072120.pdf / page 7 doesn't say
+ * samples are only of B-stepping...
+ */
+ if (ebx == 0x0e)
+ return SPEEDSTEP_CPU_P4M;
+ break;
+ case 9:
+ /*
+ * D-stepping [M-P4-M or M-P4/533]
+ *
+ * this is totally strange: CPUID 0x0F29 is
+ * used by M-P4-M, M-P4/533 and(!) Celeron CPUs.
+ * The latter need to be sorted out as they don't
+ * support speedstep.
+ * Celerons with CPUID 0x0F29 may have either
+ * ebx=0x8 or 0xf -- 25130917.pdf doesn't say anything
+ * specific.
+ * M-P4-Ms may have either ebx=0xe or 0xf [see above]
+ * M-P4/533 have either ebx=0xe or 0xf. [25317607.pdf]
+ * also, M-P4M HTs have ebx=0x8, too
+ * For now, they are distinguished by the model_id
+ * string
+ */
+ if ((ebx == 0x0e) ||
+ (strstr(c->x86_model_id,
+ "Mobile Intel(R) Pentium(R) 4") != NULL))
+ return SPEEDSTEP_CPU_P4M;
+ break;
+ default:
+ break;
+ }
+ return 0;
+ }
+
+ switch (c->x86_model) {
+ case 0x0B: /* Intel PIII [Tualatin] */
+ /* cpuid_ebx(1) is 0x04 for desktop PIII,
+ * 0x06 for mobile PIII-M */
+ ebx = cpuid_ebx(0x00000001);
+ pr_debug("ebx is %x\n", ebx);
+
+ ebx &= 0x000000FF;
+
+ if (ebx != 0x06)
+ return 0;
+
+ /* So far all PIII-M processors support SpeedStep. See
+ * Intel's 24540640.pdf of June 2003
+ */
+ return SPEEDSTEP_CPU_PIII_T;
+
+ case 0x08: /* Intel PIII [Coppermine] */
+
+ /* all mobile PIII Coppermines have FSB 100 MHz
+ * ==> sort out a few desktop PIIIs. */
+ rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_hi);
+ pr_debug("Coppermine: MSR_IA32_EBL_CR_POWERON is 0x%x, 0x%x\n",
+ msr_lo, msr_hi);
+ msr_lo &= 0x00c0000;
+ if (msr_lo != 0x0080000)
+ return 0;
+
+ /*
+ * If the processor is a mobile version,
+ * platform ID has bit 50 set
+ * it has SpeedStep technology if either
+ * bit 56 or 57 is set
+ */
+ rdmsr(MSR_IA32_PLATFORM_ID, msr_lo, msr_hi);
+ pr_debug("Coppermine: MSR_IA32_PLATFORM ID is 0x%x, 0x%x\n",
+ msr_lo, msr_hi);
+ if ((msr_hi & (1<<18)) &&
+ (relaxed_check ? 1 : (msr_hi & (3<<24)))) {
+ if (c->x86_stepping == 0x01) {
+ pr_debug("early PIII version\n");
+ return SPEEDSTEP_CPU_PIII_C_EARLY;
+ } else
+ return SPEEDSTEP_CPU_PIII_C;
+ }
+ fallthrough;
+ default:
+ return 0;
+ }
+}
+EXPORT_SYMBOL_GPL(speedstep_detect_processor);
+
+
+/*********************************************************************
+ * DETECT SPEEDSTEP SPEEDS *
+ *********************************************************************/
+
+unsigned int speedstep_get_freqs(enum speedstep_processor processor,
+ unsigned int *low_speed,
+ unsigned int *high_speed,
+ unsigned int *transition_latency,
+ void (*set_state) (unsigned int state))
+{
+ unsigned int prev_speed;
+ unsigned int ret = 0;
+ unsigned long flags;
+ ktime_t tv1, tv2;
+
+ if ((!processor) || (!low_speed) || (!high_speed) || (!set_state))
+ return -EINVAL;
+
+ pr_debug("trying to determine both speeds\n");
+
+ /* get current speed */
+ prev_speed = speedstep_get_frequency(processor);
+ if (!prev_speed)
+ return -EIO;
+
+ pr_debug("previous speed is %u\n", prev_speed);
+
+ preempt_disable();
+ local_irq_save(flags);
+
+ /* switch to low state */
+ set_state(SPEEDSTEP_LOW);
+ *low_speed = speedstep_get_frequency(processor);
+ if (!*low_speed) {
+ ret = -EIO;
+ goto out;
+ }
+
+ pr_debug("low speed is %u\n", *low_speed);
+
+ /* start latency measurement */
+ if (transition_latency)
+ tv1 = ktime_get();
+
+ /* switch to high state */
+ set_state(SPEEDSTEP_HIGH);
+
+ /* end latency measurement */
+ if (transition_latency)
+ tv2 = ktime_get();
+
+ *high_speed = speedstep_get_frequency(processor);
+ if (!*high_speed) {
+ ret = -EIO;
+ goto out;
+ }
+
+ pr_debug("high speed is %u\n", *high_speed);
+
+ if (*low_speed == *high_speed) {
+ ret = -ENODEV;
+ goto out;
+ }
+
+ /* switch to previous state, if necessary */
+ if (*high_speed != prev_speed)
+ set_state(SPEEDSTEP_LOW);
+
+ if (transition_latency) {
+ *transition_latency = ktime_to_us(ktime_sub(tv2, tv1));
+ pr_debug("transition latency is %u uSec\n", *transition_latency);
+
+ /* convert uSec to nSec and add 20% for safety reasons */
+ *transition_latency *= 1200;
+
+ /* check if the latency measurement is too high or too low
+ * and set it to a safe value (500uSec) in that case
+ */
+ if (*transition_latency > 10000000 ||
+ *transition_latency < 50000) {
+ pr_warn("frequency transition measured seems out of range (%u nSec), falling back to a safe one of %u nSec\n",
+ *transition_latency, 500000);
+ *transition_latency = 500000;
+ }
+ }
+
+out:
+ local_irq_restore(flags);
+ preempt_enable();
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(speedstep_get_freqs);
+
+#ifdef CONFIG_X86_SPEEDSTEP_RELAXED_CAP_CHECK
+module_param(relaxed_check, int, 0444);
+MODULE_PARM_DESC(relaxed_check,
+ "Don't do all checks for speedstep capability.");
+#endif
+
+MODULE_AUTHOR("Dominik Brodowski <linux@brodo.de>");
+MODULE_DESCRIPTION("Library for Intel SpeedStep 1 or 2 cpufreq drivers.");
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 14:18:12 +0000