1 files changed, 286 insertions, 0 deletions
diff --git a/drivers/cpufreq/p4-clockmod.c b/drivers/cpufreq/p4-clockmod.c
new file mode 100644
index 000000000..529cfd921
--- /dev/null
+++ b/drivers/cpufreq/p4-clockmod.c
@@ -0,0 +1,286 @@
+/*
+ *	Pentium 4/Xeon CPU on demand clock modulation/speed scaling
+ *	(C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
+ *	(C) 2002 Zwane Mwaikambo <zwane@commfireservices.com>
+ *	(C) 2002 Arjan van de Ven <arjanv@redhat.com>
+ *	(C) 2002 Tora T. Engstad
+ *	All Rights Reserved
+ *
+ *	This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ *
+ *      The author(s) of this software shall not be held liable for damages
+ *      of any nature resulting due to the use of this software. This
+ *      software is provided AS-IS with no warranties.
+ *
+ *	Date		Errata			Description
+ *	20020525	N44, O17	12.5% or 25% DC causes lockup
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/cpufreq.h>
+#include <linux/cpumask.h>
+#include <linux/timex.h>
+
+#include <asm/processor.h>
+#include <asm/msr.h>
+#include <asm/timer.h>
+#include <asm/cpu_device_id.h>
+
+#include "speedstep-lib.h"
+
+#define PFX	"p4-clockmod: "
+
+/*
+ * Duty Cycle (3bits), note DC_DISABLE is not specified in
+ * intel docs i just use it to mean disable
+ */
+enum {
+	DC_RESV, DC_DFLT, DC_25PT, DC_38PT, DC_50PT,
+	DC_64PT, DC_75PT, DC_88PT, DC_DISABLE
+};
+
+#define DC_ENTRIES	8
+
+
+static int has_N44_O17_errata[NR_CPUS];
+static unsigned int stock_freq;
+static struct cpufreq_driver p4clockmod_driver;
+static unsigned int cpufreq_p4_get(unsigned int cpu);
+
+static int cpufreq_p4_setdc(unsigned int cpu, unsigned int newstate)
+{
+	u32 l, h;
+
+	if ((newstate > DC_DISABLE) || (newstate == DC_RESV))
+		return -EINVAL;
+
+	rdmsr_on_cpu(cpu, MSR_IA32_THERM_STATUS, &l, &h);
+
+	if (l & 0x01)
+		pr_debug("CPU#%d currently thermal throttled\n", cpu);
+
+	if (has_N44_O17_errata[cpu] &&
+	    (newstate == DC_25PT || newstate == DC_DFLT))
+		newstate = DC_38PT;
+
+	rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
+	if (newstate == DC_DISABLE) {
+		pr_debug("CPU#%d disabling modulation\n", cpu);
+		wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l & ~(1<<4), h);
+	} else {
+		pr_debug("CPU#%d setting duty cycle to %d%%\n",
+			cpu, ((125 * newstate) / 10));
+		/* bits 63 - 5	: reserved
+		 * bit  4	: enable/disable
+		 * bits 3-1	: duty cycle
+		 * bit  0	: reserved
+		 */
+		l = (l & ~14);
+		l = l | (1<<4) | ((newstate & 0x7)<<1);
+		wrmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, l, h);
+	}
+
+	return 0;
+}
+
+
+static struct cpufreq_frequency_table p4clockmod_table[] = {
+	{0, DC_RESV, CPUFREQ_ENTRY_INVALID},
+	{0, DC_DFLT, 0},
+	{0, DC_25PT, 0},
+	{0, DC_38PT, 0},
+	{0, DC_50PT, 0},
+	{0, DC_64PT, 0},
+	{0, DC_75PT, 0},
+	{0, DC_88PT, 0},
+	{0, DC_DISABLE, 0},
+	{0, DC_RESV, CPUFREQ_TABLE_END},
+};
+
+
+static int cpufreq_p4_target(struct cpufreq_policy *policy, unsigned int index)
+{
+	int i;
+
+	/* run on each logical CPU,
+	 * see section 13.15.3 of IA32 Intel Architecture Software
+	 * Developer's Manual, Volume 3
+	 */
+	for_each_cpu(i, policy->cpus)
+		cpufreq_p4_setdc(i, p4clockmod_table[index].driver_data);
+
+	return 0;
+}
+
+
+static unsigned int cpufreq_p4_get_frequency(struct cpuinfo_x86 *c)
+{
+	if (c->x86 == 0x06) {
+		if (cpu_has(c, X86_FEATURE_EST))
+			printk_once(KERN_WARNING PFX "Warning: EST-capable "
+			       "CPU detected. The acpi-cpufreq module offers "
+			       "voltage scaling in addition to frequency "
+			       "scaling. You should use that instead of "
+			       "p4-clockmod, if possible.\n");
+		switch (c->x86_model) {
+		case 0x0E: /* Core */
+		case 0x0F: /* Core Duo */
+		case 0x16: /* Celeron Core */
+		case 0x1C: /* Atom */
+			p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
+			return speedstep_get_frequency(SPEEDSTEP_CPU_PCORE);
+		case 0x0D: /* Pentium M (Dothan) */
+			p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
+			/* fall through */
+		case 0x09: /* Pentium M (Banias) */
+			return speedstep_get_frequency(SPEEDSTEP_CPU_PM);
+		}
+	}
+
+	if (c->x86 != 0xF)
+		return 0;
+
+	/* on P-4s, the TSC runs with constant frequency independent whether
+	 * throttling is active or not. */
+	p4clockmod_driver.flags |= CPUFREQ_CONST_LOOPS;
+
+	if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4M) {
+		printk(KERN_WARNING PFX "Warning: Pentium 4-M detected. "
+		       "The speedstep-ich or acpi cpufreq modules offer "
+		       "voltage scaling in addition of frequency scaling. "
+		       "You should use either one instead of p4-clockmod, "
+		       "if possible.\n");
+		return speedstep_get_frequency(SPEEDSTEP_CPU_P4M);
+	}
+
+	return speedstep_get_frequency(SPEEDSTEP_CPU_P4D);
+}
+
+
+
+static int cpufreq_p4_cpu_init(struct cpufreq_policy *policy)
+{
+	struct cpuinfo_x86 *c = &cpu_data(policy->cpu);
+	int cpuid = 0;
+	unsigned int i;
+
+#ifdef CONFIG_SMP
+	cpumask_copy(policy->cpus, cpu_sibling_mask(policy->cpu));
+#endif
+
+	/* Errata workaround */
+	cpuid = (c->x86 << 8) | (c->x86_model << 4) | c->x86_mask;
+	switch (cpuid) {
+	case 0x0f07:
+	case 0x0f0a:
+	case 0x0f11:
+	case 0x0f12:
+		has_N44_O17_errata[policy->cpu] = 1;
+		pr_debug("has errata -- disabling low frequencies\n");
+	}
+
+	if (speedstep_detect_processor() == SPEEDSTEP_CPU_P4D &&
+	    c->x86_model < 2) {
+		/* switch to maximum frequency and measure result */
+		cpufreq_p4_setdc(policy->cpu, DC_DISABLE);
+		recalibrate_cpu_khz();
+	}
+	/* 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++) {
+		if ((i < 2) && (has_N44_O17_errata[policy->cpu]))
+			p4clockmod_table[i].frequency = CPUFREQ_ENTRY_INVALID;
+		else
+			p4clockmod_table[i].frequency = (stock_freq * i)/8;
+	}
+
+	/* cpuinfo and default policy values */
+
+	/* the transition latency is set to be 1 higher than the maximum
+	 * transition latency of the ondemand governor */
+	policy->cpuinfo.transition_latency = 10000001;
+
+	return cpufreq_table_validate_and_show(policy, &p4clockmod_table[0]);
+}
+
+
+static unsigned int cpufreq_p4_get(unsigned int cpu)
+{
+	u32 l, h;
+
+	rdmsr_on_cpu(cpu, MSR_IA32_THERM_CONTROL, &l, &h);
+
+	if (l & 0x10) {
+		l = l >> 1;
+		l &= 0x7;
+	} else
+		l = DC_DISABLE;
+
+	if (l != DC_DISABLE)
+		return stock_freq * l / 8;
+
+	return stock_freq;
+}
+
+static struct cpufreq_driver p4clockmod_driver = {
+	.verify		= cpufreq_generic_frequency_table_verify,
+	.target_index	= cpufreq_p4_target,
+	.init		= cpufreq_p4_cpu_init,
+	.get		= cpufreq_p4_get,
+	.name		= "p4-clockmod",
+	.attr		= cpufreq_generic_attr,
+};
+
+static const struct x86_cpu_id cpufreq_p4_id[] = {
+	{ X86_VENDOR_INTEL, X86_FAMILY_ANY, X86_MODEL_ANY, X86_FEATURE_ACC },
+	{}
+};
+
+/*
+ * Intentionally no MODULE_DEVICE_TABLE here: this driver should not
+ * be auto loaded.  Please don't add one.
+ */
+
+static int __init cpufreq_p4_init(void)
+{
+	int ret;
+
+	/*
+	 * THERM_CONTROL is architectural for IA32 now, so
+	 * we can rely on the capability checks
+	 */
+	if (!x86_match_cpu(cpufreq_p4_id) || !boot_cpu_has(X86_FEATURE_ACPI))
+		return -ENODEV;
+
+	ret = cpufreq_register_driver(&p4clockmod_driver);
+	if (!ret)
+		printk(KERN_INFO PFX "P4/Xeon(TM) CPU On-Demand Clock "
+				"Modulation available\n");
+
+	return ret;
+}
+
+
+static void __exit cpufreq_p4_exit(void)
+{
+	cpufreq_unregister_driver(&p4clockmod_driver);
+}
+
+
+MODULE_AUTHOR("Zwane Mwaikambo <zwane@commfireservices.com>");
+MODULE_DESCRIPTION("cpufreq driver for Pentium(TM) 4/Xeon(TM)");
+MODULE_LICENSE("GPL");
+
+late_initcall(cpufreq_p4_init);
+module_exit(cpufreq_p4_exit);