[CPUFREQ] Merge Jeremy's Centrino speedstep driver.

Documentation/cpu-freq/user-guide.txt

@@ -58,6 +58,7 @@ AMD mobile Athlon
 Cyrix Media GXm
 Intel mobile PIII [*] and Intel mobile PIII-M on certain chipsets
 Intel Pentium 4, Intel Xeon
+Intel Pentium M (Centrino)
 National Semiconductors Geode GX
 Transmeta Crusoe
 VIA Cyrix 3 / C3

arch/i386/kernel/cpu/cpufreq/Kconfig

@@ -104,13 +104,24 @@ config X86_SPEEDSTEP
 	depends on CPU_FREQ_TABLE
 	help
 	  This adds the CPUFreq driver for certain mobile Intel Pentium III
-	  (Coppermine), all mobile Intel Pentium III-M (Tulatin) and all
+	  (Coppermine), all mobile Intel Pentium III-M (Tualatin) and all
 	  mobile Intel Pentium 4 P4-Ms.
 
 	  For details, take a look at linux/Documentation/cpu-freq. 
 
 	  If in doubt, say N.
 
+config X86_SPEEDSTEP_CENTRINO
+	tristate "Intel Enhanced SpeedStep"
+	depends on CPU_FREQ_TABLE
+	help
+	  This adds the CPUFreq driver for Enhanced SpeedStep enabled
+	  mobile CPUs.  This means Intel Pentium M (Centrino) CPUs.
+	  
+	  For details, take a look at linux/Documentation/cpu-freq. 
+	  
+	  If in doubt, say N.
+
 config X86_P4_CLOCKMOD
 	tristate "Intel Pentium 4 clock modulation"
 	depends on CPU_FREQ_TABLE

arch/i386/kernel/cpu/cpufreq/Makefile

@@ -7,6 +7,7 @@ obj-$(CONFIG_ELAN_CPUFREQ)	+= elanfreq.o
 obj-$(CONFIG_X86_LONGRUN)	+= longrun.o  
 obj-$(CONFIG_X86_GX_SUSPMOD)    += gx-suspmod.o
 obj-$(CONFIG_X86_ACPI_CPUFREQ)	+= acpi.o
+obj-$(CONFIG_X86_SPEEDSTEP_CENTRINO) += speedstep-centrino.o
 
 ifdef CONFIG_X86_ACPI_CPUFREQ
   ifdef CONFIG_ACPI_DEBUG

arch/i386/kernel/cpu/cpufreq/speedstep-centrino.c

+/*
+ * cpufreq driver for Enhanced SpeedStep, as found in Intel's Pentium
+ * M (part of the Centrino chipset).
+ *
+ * Despite the "SpeedStep" in the name, this is almost entirely unlike
+ * traditional SpeedStep.
+ *
+ * Modelled on speedstep.c
+ *
+ * Copyright (C) 2003 Jeremy Fitzhardinge <jeremy@goop.org>
+ *
+ * WARNING WARNING WARNING
+ * 
+ * This driver manipulates the PERF_CTL MSR, which is only somewhat
+ * documented.  While it seems to work on my laptop, it has not been
+ * tested anywhere else, and it may not work for you, do strange
+ * things or simply crash.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/cpufreq.h>
+
+#include <asm/msr.h>
+#include <asm/processor.h>
+#include <asm/cpufeature.h>
+
+#define PFX		"speedstep-centrino: "
+#define MAINTAINER	"Jeremy Fitzhardinge <jeremy@goop.org>"
+
+#define CENTRINO_DEBUG
+
+#ifdef CENTRINO_DEBUG
+#define dprintk(msg...) printk(msg)
+#else
+#define dprintk(msg...) do { } while(0)
+#endif
+
+struct cpu_model
+{
+	const char	*model_name;
+	unsigned	max_freq; /* max clock in kHz */
+
+	struct cpufreq_frequency_table *op_points; /* clock/voltage pairs */
+};
+
+/* Operating points for current CPU */
+static const struct cpu_model *centrino_model;
+
+/* Computes the correct form for IA32_PERF_CTL MSR for a particular
+   frequency/voltage operating point; frequency in MHz, volts in mV.
+   This is stored as "index" in the structure. */
+#define OP(mhz, mv)							\
+	{								\
+		.frequency = (mhz) * 1000,				\
+		.index = (((mhz)/100) << 8) | ((mv - 700) / 16)		\
+	}
+
+/* 
+ * These voltage tables were derived from the Intel Pentium M
+ * datasheet, document 25261202.pdf, Table 5.  I have verified they
+ * are consistent with my IBM ThinkPad X31, which has a 1.3GHz Pentium
+ * M.
+ */
+
+/* Ultra Low Voltage Intel Pentium M processor 900MHz */
+static struct cpufreq_frequency_table op_900[] =
+{
+	OP(600,  844),
+	OP(800,  988),
+	OP(900, 1004),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+
+/* Low Voltage Intel Pentium M processor 1.10GHz */
+static struct cpufreq_frequency_table op_1100[] =
+{
+	OP( 600,  956),
+	OP( 800, 1020),
+	OP( 900, 1100),
+	OP(1000, 1164),
+	OP(1100, 1180),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+
+
+/* Low Voltage Intel Pentium M processor 1.20GHz */
+static struct cpufreq_frequency_table op_1200[] =
+{
+	OP( 600,  956),
+	OP( 800, 1004),
+	OP( 900, 1020),
+	OP(1000, 1100),
+	OP(1100, 1164),
+	OP(1200, 1180),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+
+/* Intel Pentium M processor 1.30GHz */
+static struct cpufreq_frequency_table op_1300[] = 
+{
+	OP( 600,  956),
+	OP( 800, 1260),
+	OP(1000, 1292),
+	OP(1200, 1356),
+	OP(1300, 1388),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+
+/* Intel Pentium M processor 1.40GHz */
+static struct cpufreq_frequency_table op_1400[] = 
+{
+	OP( 600,  956),
+	OP( 800, 1180),
+	OP(1000, 1308),
+	OP(1200, 1436),
+	OP(1400, 1484),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+
+/* Intel Pentium M processor 1.50GHz */
+static struct cpufreq_frequency_table op_1500[] = 
+{
+	OP( 600,  956),
+	OP( 800, 1116),
+	OP(1000, 1228),
+	OP(1200, 1356),
+	OP(1400, 1452),
+	OP(1500, 1484),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+
+/* Intel Pentium M processor 1.60GHz */
+static struct cpufreq_frequency_table op_1600[] = 
+{
+	OP( 600,  956),
+	OP( 800, 1036),
+	OP(1000, 1164),
+	OP(1200, 1276),
+	OP(1400, 1420),
+	OP(1600, 1484),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+
+/* Intel Pentium M processor 1.70GHz */
+static struct cpufreq_frequency_table op_1700[] =
+{
+	OP( 600,  956),
+	OP( 800, 1004),
+	OP(1000, 1116),
+	OP(1200, 1228),
+	OP(1400, 1308),
+	OP(1700, 1484),
+	{ .frequency = CPUFREQ_TABLE_END }
+};
+#undef OP
+
+#define CPU(max)	\
+	{ "Intel(R) Pentium(R) M processor " #max "MHz", (max)*1000, op_##max }
+
+/* CPU models, their operating frequency range, and freq/voltage
+   operating points */
+static const struct cpu_model models[] = 
+{
+	CPU( 900),
+	CPU(1100),
+	CPU(1200),
+	CPU(1300),
+	CPU(1400),
+	CPU(1500),
+	CPU(1600),
+	CPU(1700),
+	{ 0, }
+};
+#undef CPU
+
+/* Extract clock in kHz from PERF_CTL value */
+static unsigned extract_clock(unsigned msr)
+{
+	msr = (msr >> 8) & 0xff;
+	return msr * 100000;
+}
+
+/* Return the current CPU frequency in kHz */
+static unsigned get_cur_freq(void)
+{
+	unsigned l, h;
+
+	rdmsr(MSR_IA32_PERF_STATUS, l, h);
+	return extract_clock(l);
+}
+
+static int centrino_cpu_init(struct cpufreq_policy *policy)
+{
+	unsigned freq;
+
+	if (policy->cpu != 0 || centrino_model == NULL)
+		return -ENODEV;
+
+	freq = get_cur_freq();
+
+	policy->policy = (freq == centrino_model->max_freq) ? 
+		CPUFREQ_POLICY_PERFORMANCE : 
+		CPUFREQ_POLICY_POWERSAVE;
+	policy->cpuinfo.transition_latency = 10; /* 10uS transition latency */
+	policy->cur = freq;
+
+	dprintk(KERN_INFO PFX "centrino_cpu_init: policy=%d cur=%dkHz\n",
+		policy->policy, policy->cur);
+	
+	return cpufreq_frequency_table_cpuinfo(policy, centrino_model->op_points);
+}
+
+/**
+ * centrino_verify - verifies a new CPUFreq policy
+ * @freq: new policy
+ *
+ * Limit must be within this model's frequency range at least one
+ * border included.
+ */
+static int centrino_verify (struct cpufreq_policy *policy)
+{
+	return cpufreq_frequency_table_verify(policy, centrino_model->op_points);
+}
+
+/**
+ * centrino_setpolicy - set a new CPUFreq policy
+ * @policy: new policy
+ *
+ * Sets a new CPUFreq policy.
+ */
+static int centrino_target (struct cpufreq_policy *policy,
+			    unsigned int target_freq,
+			    unsigned int relation)
+{
+	unsigned int    newstate = 0;
+	unsigned int	msr, oldmsr, h;
+	struct cpufreq_freqs	freqs;
+
+	if (centrino_model == NULL)
+		return -ENODEV;
+
+	if (cpufreq_frequency_table_target(policy, centrino_model->op_points, target_freq,
+					   relation, &newstate))
+		return -EINVAL;
+
+	msr = centrino_model->op_points[newstate].index;
+	rdmsr(MSR_IA32_PERF_CTL, oldmsr, h);
+
+	if (msr == (oldmsr & 0xffff))
+		return 0;
+
+	/* Hm, old frequency can either be the last value we put in
+	   PERF_CTL, or whatever it is now. The trouble is that TM2
+	   can change it behind our back, which means we never get to
+	   see the speed change.  Reading back the current speed would
+	   tell us something happened, but it may leave the things on
+	   the notifier chain confused; we therefore stick to using
+	   the last programmed speed rather than the current speed for
+	   "old". 
+
+	   TODO: work out how the TCC interrupts work, and try to
+	   catch the CPU changing things under us.
+	*/
+	freqs.cpu = 0;
+	freqs.old = extract_clock(oldmsr);
+	freqs.new = extract_clock(msr);
+	
+	dprintk(KERN_INFO PFX "target=%dkHz old=%d new=%d msr=%04x\n",
+		target_freq, freqs.old, freqs.new, msr);
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);	
+
+	/* all but 16 LSB are "reserved", so treat them with
+	   care */
+	oldmsr &= ~0xffff;
+	msr &= 0xffff;
+	oldmsr |= msr;
+	
+	wrmsr(MSR_IA32_PERF_CTL, oldmsr, h);
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+	return 0;
+}
+
+static struct cpufreq_driver centrino_driver = {
+	.name		= "centrino", /* should be speedstep-centrino, 
+					 but there's a 16 char limit */
+	.init		= centrino_cpu_init,
+	.verify 	= centrino_verify,
+	.target 	= centrino_target,
+	.owner		= THIS_MODULE,
+};
+
+
+/**
+ * centrino_init - initializes the Enhanced SpeedStep CPUFreq driver
+ *
+ * Initializes the Enhanced SpeedStep support. Returns -ENODEV on
+ * unsupported devices, -ENOENT if there's no voltage table for this
+ * particular CPU model, -EINVAL on problems during initiatization,
+ * and zero on success.
+ *
+ * This is quite picky.  Not only does the CPU have to advertise the
+ * "est" flag in the cpuid capability flags, we look for a specific
+ * CPU model and stepping, and we need to have the exact model name in
+ * our voltage tables.  That is, be paranoid about not releasing
+ * someone's valuable magic smoke.
+ */
+static int __init centrino_init(void)
+{
+	struct cpuinfo_x86 *cpu = cpu_data;
+	const struct cpu_model *model;
+	unsigned l, h;
+
+	if (!cpu_has(cpu, X86_FEATURE_EST))
+		return -ENODEV;
+
+	/* Only Intel Pentium M stepping 5 for now - add new CPUs as
+	   they appear after making sure they use PERF_CTL in the same
+	   way. */
+	if (cpu->x86_vendor != X86_VENDOR_INTEL ||
+	    cpu->x86        != 6 ||
+	    cpu->x86_model  != 9 ||
+	    cpu->x86_mask   != 5) {
+		printk(KERN_INFO PFX "found unsupported CPU with Enhanced SpeedStep: "
+		       "send /proc/cpuinfo to " MAINTAINER "\n");
+		return -ENODEV;
+	}
+
+	/* Check to see if Enhanced SpeedStep is enabled, and try to
+	   enable it if not. */
+	rdmsr(MSR_IA32_MISC_ENABLE, l, h);
+		
+	if (!(l & (1<<16))) {
+		l |= (1<<16);
+		wrmsr(MSR_IA32_MISC_ENABLE, l, h);
+		
+		/* check to see if it stuck */
+		rdmsr(MSR_IA32_MISC_ENABLE, l, h);
+		if (!(l & (1<<16))) {
+			printk(KERN_INFO PFX "couldn't enable Enhanced SpeedStep\n");
+			return -ENODEV;
+		}
+	}
+
+	for(model = models; model->model_name != NULL; model++)
+		if (strcmp(cpu->x86_model_id, model->model_name) == 0)
+			break;
+	if (model->model_name == NULL) {
+		printk(KERN_INFO PFX "no support for CPU model \"%s\": "
+		       "send /proc/cpuinfo to " MAINTAINER "\n",
+		       cpu->x86_model_id);
+		return -ENOENT;
+	}
+
+	centrino_model = model;
+		
+	printk(KERN_INFO PFX "found \"%s\": max frequency: %dkHz\n",
+	       model->model_name, model->max_freq);
+
+	return cpufreq_register_driver(&centrino_driver);
+}
+
+static void __exit centrino_exit(void)
+{
+	cpufreq_unregister_driver(&centrino_driver);
+}
+
+MODULE_AUTHOR ("Jeremy Fitzhardinge <jeremy@goop.org>");
+MODULE_DESCRIPTION ("Enhanced SpeedStep driver for Intel Pentium M processors.");
+MODULE_LICENSE ("GPL");
+
+module_init(centrino_init);
+module_exit(centrino_exit);

include/asm-i386/cpufeature.h

@@ -70,6 +70,7 @@
 #define X86_FEATURE_P4		(3*32+ 7) /* P4 */
 
 /* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */
+#define X86_FEATURE_EST		(4*32+ 7) /* Enhanced SpeedStep */
 
 /* VIA/Cyrix/Centaur-defined CPU features, CPUID level 0xC0000001, word 5 */
 #define X86_FEATURE_XSTORE	(5*32+ 2) /* on-CPU RNG present (xstore insn) */

include/asm-i386/msr.h

@@ -77,6 +77,9 @@
 #define MSR_P6_EVNTSEL0			0x186
 #define MSR_P6_EVNTSEL1			0x187
 
+#define MSR_IA32_PERF_STATUS		0x198
+#define MSR_IA32_PERF_CTL		0x199
+
 #define MSR_IA32_THERM_CONTROL		0x19a
 #define MSR_IA32_THERM_INTERRUPT	0x19b
 #define MSR_IA32_THERM_STATUS		0x19c