From f162ed116075cc88f447e069807338ce7513a974 Mon Sep 17 00:00:00 2001 From: Dave Jones Date: Mon, 5 Jan 2004 18:31:40 +0000 Subject: [PATCH] [CPUFREQ] Detect CPU speed without relying on cpu_khz --- arch/i386/kernel/cpu/cpufreq/p4-clockmod.c | 66 +++++++++++++++++----- 1 file changed, 53 insertions(+), 13 deletions(-) diff --git a/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c b/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c index da3e11035e3a0..06cb5d7b4ba16 100644 --- a/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c +++ b/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c @@ -48,8 +48,7 @@ enum { static int has_N44_O17_errata[NR_CPUS]; -static int stock_freq; - +static unsigned int stock_freq; static int cpufreq_p4_setdc(unsigned int cpu, unsigned int newstate) { @@ -175,6 +174,54 @@ static int cpufreq_p4_verify(struct cpufreq_policy *policy) return cpufreq_frequency_table_verify(policy, &p4clockmod_table[0]); } +/* copied from speedstep_lib, made SMP-compatible */ +static unsigned int cpufreq_p4_get_frequency(struct cpuinfo_x86 *c) +{ + u32 msr_lo, msr_hi, mult; + unsigned int fsb = 0; + + if (c->x86 != 0xF) { + printk(KERN_DEBUG PFX "Unknown P4. Please send an e-mail to \n"); + return 0; + } + + rdmsr(0x2c, msr_lo, msr_hi); + + /* printk(KERN_DEBUG PFX "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. + */ + if (c->x86_model < 2) + fsb = 100 * 1000; + else { + u8 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 \n"); + printk(KERN_DEBUG PFX "P4 - MSR_EBC_FREQUENCY_ID: 0x%x 0x%x\n", msr_lo, msr_hi); + } + + /* Multiplier. */ + mult = msr_lo >> 24; + + return (fsb * mult); +} + + static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy) { @@ -192,15 +239,10 @@ static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy) has_N44_O17_errata[policy->cpu] = 1; } - /* get frequency */ - if (!stock_freq) { - if (cpu_khz) - stock_freq = cpu_khz; - else { - printk(KERN_INFO PFX "unknown core frequency - please use module parameter 'stock_freq'\n"); - return -EINVAL; - } - } + /* get max frequency */ + stock_freq = cpufreq_p4_get_frequency(c); + if (!stock_freq) + return -EINVAL; /* table init */ for (i=1; (p4clockmod_table[i].frequency != CPUFREQ_TABLE_END); i++) { @@ -269,8 +311,6 @@ static void __exit cpufreq_p4_exit(void) } -MODULE_PARM(stock_freq, "i"); - MODULE_AUTHOR ("Zwane Mwaikambo "); MODULE_DESCRIPTION ("cpufreq driver for Pentium(TM) 4/Xeon(TM)"); MODULE_LICENSE ("GPL"); -- 2.53.0