From: Dominik Brodowski <linux@dominikbrodowski.de>
To: davej@codemonkey.org.uk, cpufreq@www.linux.org.uk, akpm@osdl.org
Subject: [PATCH] fix up CPU detection in p4-clockmod
Date: Sat, 10 Jan 2004 16:12:48 +0100 [thread overview]
Message-ID: <20040110151248.GA7989@dominikbrodowski.de> (raw)
Too many users use the p4-clockmod cpufreq driver instead of the more
advanced speedstep-centrino, speedstep-ich or even acpi drivers. All of the
latter (usually) provide voltage scaling, while the p4-clockmod driver only
offers a variant of frequency scaling. So, warn users if they try out this
driver instead.
Also, instead of using a local copy, use the speedstep_lib infrastructure
for detecting the processor speed. Adding the Pentium-M get_frequency
function to that module only costs about 200 bytes in object size.
arch/i386/kernel/cpu/cpufreq/Kconfig | 10 ++--
arch/i386/kernel/cpu/cpufreq/p4-clockmod.c | 55 ++++++++-------------------
arch/i386/kernel/cpu/cpufreq/speedstep-lib.c | 23 +++++++++++
arch/i386/kernel/cpu/cpufreq/speedstep-lib.h | 6 ++
4 files changed, 52 insertions(+), 42 deletions(-)
diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/Kconfig linux/arch/i386/kernel/cpu/cpufreq/Kconfig
--- linux-original/arch/i386/kernel/cpu/cpufreq/Kconfig 2004-01-10 14:54:45.000000000 +0100
+++ linux/arch/i386/kernel/cpu/cpufreq/Kconfig 2004-01-10 15:25:20.000000000 +0100
@@ -145,11 +145,6 @@
If in doubt, say N.
-config X86_SPEEDSTEP_LIB
- tristate
- depends on (X86_SPEEDSTEP_ICH || X86_SPEEDSTEP_SMI)
- default (X86_SPEEDSTEP_ICH || X86_SPEEDSTEP_SMI)
-
config X86_P4_CLOCKMOD
tristate "Intel Pentium 4 clock modulation"
depends on CPU_FREQ_TABLE
@@ -161,6 +156,11 @@
If in doubt, say N.
+config X86_SPEEDSTEP_LIB
+ tristate
+ depends on (X86_SPEEDSTEP_ICH || X86_SPEEDSTEP_SMI || X86_P4_CLOCKMOD)
+ default (X86_SPEEDSTEP_ICH || X86_SPEEDSTEP_SMI || X86_P4_CLOCKMOD)
+
config X86_LONGRUN
tristate "Transmeta LongRun"
depends on CPU_FREQ
diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c linux/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c
--- linux-original/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c 2004-01-10 14:54:45.000000000 +0100
+++ linux/arch/i386/kernel/cpu/cpufreq/p4-clockmod.c 2004-01-10 15:41:06.785375544 +0100
@@ -33,6 +33,8 @@
#include <asm/msr.h>
#include <asm/timex.h>
+#include "speedstep-lib.h"
+
#define PFX "cpufreq: "
/*
@@ -174,51 +176,30 @@
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 == 0x06) && (c->x86_model == 0x09)) {
+ /* Pentium M */
+ printk(KERN_DEBUG PFX "Warning: Pentium M detected. The speedstep_centrino module\n");
+ printk(KERN_DEBUG PFX "offers voltage scaling in addition of frequency scaling. You\n");
+ printk(KERN_DEBUG PFX "should use that instead of p4-clockmod, if possible.\n");
+ return speedstep_get_processor_frequency(SPEEDSTEP_PROCESSOR_PM);
+ }
if (c->x86 != 0xF) {
- printk(KERN_DEBUG PFX "Unknown P4. Please send an e-mail to <linux@brodo.de>\n");
+ printk(KERN_DEBUG PFX "Unknown p4-clockmod-capable CPU. Please send an e-mail to <linux@brodo.de>\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 <linux@brodo.de>\n");
- printk(KERN_DEBUG PFX "P4 - MSR_EBC_FREQUENCY_ID: 0x%x 0x%x\n", msr_lo, msr_hi);
+ if (speedstep_detect_processor() == SPEEDSTEP_PROCESSOR_P4M) {
+ printk(KERN_DEBUG PFX "Warning: Pentium 4-M detected. The speedstep-ich or acpi cpufreq \n");
+ printk(KERN_DEBUG PFX "modules offers voltage scaling in addition of frequency scaling. You\n");
+ printk(KERN_DEBUG PFX "should use either one instead of p4-clockmod, if possible.\n");
+ return speedstep_get_processor_frequency(SPEEDSTEP_PROCESSOR_P4M);
}
- /* Multiplier. */
- mult = msr_lo >> 24;
-
- return (fsb * mult);
+ return speedstep_get_processor_frequency(SPEEDSTEP_PROCESSOR_P4D);
}
@@ -315,6 +296,6 @@
MODULE_DESCRIPTION ("cpufreq driver for Pentium(TM) 4/Xeon(TM)");
MODULE_LICENSE ("GPL");
-module_init(cpufreq_p4_init);
+late_initcall(cpufreq_p4_init);
module_exit(cpufreq_p4_exit);
diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c linux/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c
--- linux-original/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c 2004-01-10 14:54:45.000000000 +0100
+++ linux/arch/i386/kernel/cpu/cpufreq/speedstep-lib.c 2004-01-10 15:38:57.991955120 +0100
@@ -104,6 +104,26 @@
}
+static unsigned int pentiumM_get_frequency(void)
+{
+ u32 msr_lo, msr_tmp;
+
+ rdmsr(MSR_IA32_EBL_CR_POWERON, msr_lo, msr_tmp);
+ dprintk(KERN_DEBUG "speedstep-lib: 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 "speedstep-lib: PM - invalid FSB: 0x%x 0x%x\n", msr_lo, msr_tmp);
+ return 0;
+ }
+
+ msr_tmp = (msr_lo >> 22) & 0x1f;
+ dprintk(KERN_DEBUG "speedstep-lib: bits 22-26 are 0x%x\n", msr_tmp);
+
+ return (msr_tmp * 100 * 10000);
+}
+
+
static unsigned int pentium4_get_frequency(void)
{
struct cpuinfo_x86 *c = &boot_cpu_data;
@@ -151,6 +171,9 @@
unsigned int speedstep_get_processor_frequency(unsigned int processor)
{
switch (processor) {
+ case SPEEDSTEP_PROCESSOR_PM:
+ return pentiumM_get_frequency();
+ case SPEEDSTEP_PROCESSOR_P4D:
case SPEEDSTEP_PROCESSOR_P4M:
return pentium4_get_frequency();
case SPEEDSTEP_PROCESSOR_PIII_T:
diff -ruN linux-original/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h linux/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h
--- linux-original/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h 2004-01-10 14:54:45.000000000 +0100
+++ linux/arch/i386/kernel/cpu/cpufreq/speedstep-lib.h 2004-01-10 15:26:23.000000000 +0100
@@ -17,6 +17,12 @@
#define SPEEDSTEP_PROCESSOR_PIII_T 0x00000003 /* Tualatin core */
#define SPEEDSTEP_PROCESSOR_P4M 0x00000004 /* P4-M */
+/* the following processors are not speedstep-capable and are not auto-detected
+ * in speedstep_detect_processor(). However, their speed can be detected using
+ * the speedstep_get_processor_frequency() call. */
+#define SPEEDSTEP_PROCESSOR_PM 0xFFFFFF03 /* Pentium M */
+#define SPEEDSTEP_PROCESSOR_P4D 0xFFFFFF04 /* desktop P4 */
+
/* speedstep states -- only two of them */
#define SPEEDSTEP_HIGH 0x00000000
next reply other threads:[~2004-01-10 15:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-01-10 15:12 Dominik Brodowski [this message]
2004-01-10 15:50 ` [PATCH] fix up CPU detection in p4-clockmod Dave Jones
2004-01-10 16:19 ` Dominik Brodowski
2004-01-10 22:19 ` Andrew Morton
2004-01-11 11:33 ` Dominik Brodowski
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