vserver 1.9.5.x5
[linux-2.6.git] / arch / i386 / kernel / cpu / cpufreq / speedstep-centrino.c
index f84f9af..07d5612 100644 (file)
@@ -10,7 +10,7 @@
  * 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
 #include <linux/init.h>
 #include <linux/cpufreq.h>
 #include <linux/config.h>
+#include <linux/delay.h>
+#include <linux/compiler.h>
+
+#ifdef CONFIG_X86_SPEEDSTEP_CENTRINO_ACPI
+#include <linux/acpi.h>
+#include <acpi/processor.h>
+#endif
 
 #include <asm/msr.h>
 #include <asm/processor.h>
 #include <asm/cpufeature.h>
 
+#include "speedstep-est-common.h"
+
 #define PFX            "speedstep-centrino: "
 #define MAINTAINER     "Jeremy Fitzhardinge <jeremy@goop.org>"
 
-/*#define CENTRINO_DEBUG*/
+#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "speedstep-centrino", msg)
 
-#ifdef CENTRINO_DEBUG
-#define dprintk(msg...) printk(msg)
-#else
-#define dprintk(msg...) do { } while(0)
-#endif
 
 struct cpu_id
 {
        __u8    x86;            /* CPU family */
-       __u8    x86_vendor;     /* CPU vendor */
        __u8    x86_model;      /* model */
        __u8    x86_mask;       /* stepping */
 };
 
-static const struct cpu_id cpu_id_banias = {
-       .x86_vendor = X86_VENDOR_INTEL,
-       .x86 = 6,
-       .x86_model = 9,
-       .x86_mask = 5,
+enum {
+       CPU_BANIAS,
+       CPU_DOTHAN_A1,
+       CPU_DOTHAN_A2,
+       CPU_DOTHAN_B0,
 };
 
-static const struct cpu_id cpu_id_dothan_a1 = {
-       .x86_vendor = X86_VENDOR_INTEL,
-       .x86 = 6,
-       .x86_model = 13,
-       .x86_mask = 1,
+static const struct cpu_id cpu_ids[] = {
+       [CPU_BANIAS]    = { 6,  9, 5 },
+       [CPU_DOTHAN_A1] = { 6, 13, 1 },
+       [CPU_DOTHAN_A2] = { 6, 13, 2 },
+       [CPU_DOTHAN_B0] = { 6, 13, 6 },
 };
+#define N_IDS  (sizeof(cpu_ids)/sizeof(cpu_ids[0]))
 
 struct cpu_model
 {
@@ -68,10 +72,13 @@ struct cpu_model
 
        struct cpufreq_frequency_table *op_points; /* clock/voltage pairs */
 };
-static int centrino_verify_cpu_id(struct cpuinfo_x86 *c, const struct cpu_id *x);
+static int centrino_verify_cpu_id(const struct cpuinfo_x86 *c, const struct cpu_id *x);
 
 /* Operating points for current CPU */
-static struct cpu_model *centrino_model;
+static struct cpu_model *centrino_model[NR_CPUS];
+static const struct cpu_id *centrino_cpu[NR_CPUS];
+
+static struct cpufreq_driver centrino_driver;
 
 #ifdef CONFIG_X86_SPEEDSTEP_CENTRINO_TABLE
 
@@ -84,7 +91,7 @@ static struct cpu_model *centrino_model;
                .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
@@ -103,9 +110,9 @@ static struct cpufreq_frequency_table banias_900[] =
 /* Ultra Low Voltage Intel Pentium M processor 1000MHz (Banias) */
 static struct cpufreq_frequency_table banias_1000[] =
 {
-       OP(600,  844),
-       OP(800,  972),
-       OP(900,  988),
+       OP(600,   844),
+       OP(800,   972),
+       OP(900,   988),
        OP(1000, 1004),
        { .frequency = CPUFREQ_TABLE_END }
 };
@@ -135,7 +142,7 @@ static struct cpufreq_frequency_table banias_1200[] =
 };
 
 /* Intel Pentium M processor 1.30GHz (Banias) */
-static struct cpufreq_frequency_table banias_1300[] = 
+static struct cpufreq_frequency_table banias_1300[] =
 {
        OP( 600,  956),
        OP( 800, 1260),
@@ -146,7 +153,7 @@ static struct cpufreq_frequency_table banias_1300[] =
 };
 
 /* Intel Pentium M processor 1.40GHz (Banias) */
-static struct cpufreq_frequency_table banias_1400[] = 
+static struct cpufreq_frequency_table banias_1400[] =
 {
        OP( 600,  956),
        OP( 800, 1180),
@@ -157,7 +164,7 @@ static struct cpufreq_frequency_table banias_1400[] =
 };
 
 /* Intel Pentium M processor 1.50GHz (Banias) */
-static struct cpufreq_frequency_table banias_1500[] = 
+static struct cpufreq_frequency_table banias_1500[] =
 {
        OP( 600,  956),
        OP( 800, 1116),
@@ -169,7 +176,7 @@ static struct cpufreq_frequency_table banias_1500[] =
 };
 
 /* Intel Pentium M processor 1.60GHz (Banias) */
-static struct cpufreq_frequency_table banias_1600[] = 
+static struct cpufreq_frequency_table banias_1600[] =
 {
        OP( 600,  956),
        OP( 800, 1036),
@@ -199,13 +206,13 @@ static struct cpufreq_frequency_table banias_1700[] =
        .max_freq       = (max)*1000,   \
        .op_points      = banias_##max, \
 }
-#define BANIAS(max)    _BANIAS(&cpu_id_banias, max, #max)
+#define BANIAS(max)    _BANIAS(&cpu_ids[CPU_BANIAS], max, #max)
 
 /* CPU models, their operating frequency range, and freq/voltage
    operating points */
-static struct cpu_model models[] = 
+static struct cpu_model models[] =
 {
-       _BANIAS(&cpu_id_banias, 900, " 900"),
+       _BANIAS(&cpu_ids[CPU_BANIAS], 900, " 900"),
        BANIAS(1000),
        BANIAS(1100),
        BANIAS(1200),
@@ -214,7 +221,13 @@ static struct cpu_model models[] =
        BANIAS(1500),
        BANIAS(1600),
        BANIAS(1700),
-       { 0, }
+
+       /* NULL model_name is a wildcard */
+       { &cpu_ids[CPU_DOTHAN_A1], NULL, 0, NULL },
+       { &cpu_ids[CPU_DOTHAN_A2], NULL, 0, NULL },
+       { &cpu_ids[CPU_DOTHAN_B0], NULL, 0, NULL },
+
+       { NULL, }
 };
 #undef _BANIAS
 #undef BANIAS
@@ -224,20 +237,33 @@ static int centrino_cpu_init_table(struct cpufreq_policy *policy)
        struct cpuinfo_x86 *cpu = &cpu_data[policy->cpu];
        struct cpu_model *model;
 
-       for(model = models; model->model_name != NULL; model++)
-               if ((strcmp(cpu->x86_model_id, model->model_name) == 0) &&
-                   (!centrino_verify_cpu_id(cpu, model->cpu_id)))
+       for(model = models; model->cpu_id != NULL; model++)
+               if (centrino_verify_cpu_id(cpu, model->cpu_id) &&
+                   (model->model_name == NULL ||
+                    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\": "
+
+       if (model->cpu_id == NULL) {
+               /* No match at all */
+               dprintk(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",
+       if (model->op_points == NULL) {
+               /* Matched a non-match */
+               dprintk(KERN_INFO PFX "no table support for CPU model \"%s\": \n",
+                      cpu->x86_model_id);
+#ifndef CONFIG_X86_SPEEDSTEP_CENTRINO_ACPI
+               dprintk(KERN_INFO PFX "try compiling with CONFIG_X86_SPEEDSTEP_CENTRINO_ACPI enabled\n");
+#endif
+               return -ENOENT;
+       }
+
+       centrino_model[policy->cpu] = model;
+
+       dprintk("found \"%s\": max frequency: %dkHz\n",
               model->model_name, model->max_freq);
 
        return 0;
@@ -247,32 +273,74 @@ static int centrino_cpu_init_table(struct cpufreq_policy *policy)
 static inline int centrino_cpu_init_table(struct cpufreq_policy *policy) { return -ENODEV; }
 #endif /* CONFIG_X86_SPEEDSTEP_CENTRINO_TABLE */
 
-static int centrino_verify_cpu_id(struct cpuinfo_x86 *c, const struct cpu_id *x)
+static int centrino_verify_cpu_id(const struct cpuinfo_x86 *c, const struct cpu_id *x)
 {
        if ((c->x86 == x->x86) &&
-           (c->x86_vendor == x->x86_vendor) &&
            (c->x86_model == x->x86_model) &&
            (c->x86_mask == x->x86_mask))
-               return 0;
-       return -ENODEV;
+               return 1;
+       return 0;
 }
 
-/* Extract clock in kHz from PERF_CTL value */
-static unsigned extract_clock(unsigned msr)
+/* To be called only after centrino_model is initialized */
+static unsigned extract_clock(unsigned msr, unsigned int cpu, int failsafe)
 {
-       msr = (msr >> 8) & 0xff;
-       return msr * 100000;
+       int i;
+
+       /*
+        * Extract clock in kHz from PERF_CTL value
+        * for centrino, as some DSDTs are buggy.
+        * Ideally, this can be done using the acpi_data structure.
+        */
+       if ((centrino_cpu[cpu] == &cpu_ids[CPU_BANIAS]) ||
+           (centrino_cpu[cpu] == &cpu_ids[CPU_DOTHAN_A1]) ||
+           (centrino_cpu[cpu] == &cpu_ids[CPU_DOTHAN_B0])) {
+               msr = (msr >> 8) & 0xff;
+               return msr * 100000;
+       }
+
+       if ((!centrino_model[cpu]) || (!centrino_model[cpu]->op_points))
+               return 0;
+
+       msr &= 0xffff;
+       for (i=0;centrino_model[cpu]->op_points[i].frequency != CPUFREQ_TABLE_END; i++) {
+               if (msr == centrino_model[cpu]->op_points[i].index)
+                       return centrino_model[cpu]->op_points[i].frequency;
+       }
+       if (failsafe)
+               return centrino_model[cpu]->op_points[i-1].frequency;
+       else
+               return 0;
 }
 
 /* Return the current CPU frequency in kHz */
 static unsigned int get_cur_freq(unsigned int cpu)
 {
        unsigned l, h;
-       if (cpu)
+       unsigned clock_freq;
+       cpumask_t saved_mask;
+
+       saved_mask = current->cpus_allowed;
+       set_cpus_allowed(current, cpumask_of_cpu(cpu));
+       if (smp_processor_id() != cpu)
                return 0;
 
        rdmsr(MSR_IA32_PERF_STATUS, l, h);
-       return extract_clock(l);
+       clock_freq = extract_clock(l, cpu, 0);
+
+       if (unlikely(clock_freq == 0)) {
+               /*
+                * On some CPUs, we can see transient MSR values (which are
+                * not present in _PSS), while CPU is doing some automatic
+                * P-state transition (like TM2). Get the last freq set 
+                * in PERF_CTL.
+                */
+               rdmsr(MSR_IA32_PERF_CTL, l, h);
+               clock_freq = extract_clock(l, cpu, 1);
+       }
+
+       set_cpus_allowed(current, saved_mask);
+       return clock_freq;
 }
 
 
@@ -280,13 +348,8 @@ static unsigned int get_cur_freq(unsigned int cpu)
 
 static struct acpi_processor_performance p;
 
-#include <linux/acpi.h>
-#include <acpi/processor.h>
-
-#define ACPI_PDC_CAPABILITY_ENHANCED_SPEEDSTEP 0x1
-
 /*
- * centrino_cpu_init_acpi - register with ACPI P-States library 
+ * centrino_cpu_init_acpi - register with ACPI P-States library
  *
  * Register with the ACPI P-States library (part of drivers/acpi/processor.c)
  * in order to determine correct frequency and voltage pairings by reading
@@ -296,90 +359,121 @@ static int centrino_cpu_init_acpi(struct cpufreq_policy *policy)
 {
        union acpi_object               arg0 = {ACPI_TYPE_BUFFER};
        u32                             arg0_buf[3];
-       struct acpi_object_list         arg_list = {1, &arg0};
+       struct acpi_object_list         arg_list = {1, &arg0};
        unsigned long                   cur_freq;
        int                             result = 0, i;
+       unsigned int                    cpu = policy->cpu;
 
        /* _PDC settings */
-        arg0.buffer.length = 12;
-        arg0.buffer.pointer = (u8 *) arg0_buf;
-        arg0_buf[0] = ACPI_PDC_REVISION_ID;
-        arg0_buf[1] = 1;
-        arg0_buf[2] = ACPI_PDC_CAPABILITY_ENHANCED_SPEEDSTEP;
+       arg0.buffer.length = 12;
+       arg0.buffer.pointer = (u8 *) arg0_buf;
+       arg0_buf[0] = ACPI_PDC_REVISION_ID;
+       arg0_buf[1] = 1;
+       arg0_buf[2] = ACPI_PDC_EST_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_MSR;
 
        p.pdc = &arg_list;
 
        /* register with ACPI core */
-        if (acpi_processor_register_performance(&p, 0))
-                return -EIO;
+       if (acpi_processor_register_performance(&p, cpu)) {
+               dprintk(KERN_INFO PFX "obtaining ACPI data failed\n");
+               return -EIO;
+       }
 
        /* verify the acpi_data */
        if (p.state_count <= 1) {
-                printk(KERN_DEBUG "No P-States\n");
-                result = -ENODEV;
-                goto err_unreg;
-       }
+               dprintk("No P-States\n");
+               result = -ENODEV;
+               goto err_unreg;
+       }
 
        if ((p.control_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) ||
            (p.status_register.space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)) {
-               printk(KERN_DEBUG "Invalid control/status registers\n");
+               dprintk("Invalid control/status registers (%x - %x)\n",
+                       p.control_register.space_id, p.status_register.space_id);
                result = -EIO;
                goto err_unreg;
        }
 
        for (i=0; i<p.state_count; i++) {
                if (p.states[i].control != p.states[i].status) {
-                       printk(KERN_DEBUG "Different control and status values\n");
+                       dprintk("Different control (%x) and status values (%x)\n",
+                               p.states[i].control, p.states[i].status);
                        result = -EINVAL;
                        goto err_unreg;
                }
 
                if (!p.states[i].core_frequency) {
-                       printk(KERN_DEBUG "Zero core frequency\n");
+                       dprintk("Zero core frequency for state %u\n", i);
                        result = -EINVAL;
                        goto err_unreg;
                }
 
-               if (extract_clock(p.states[i].control) != 
-                   (p.states[i].core_frequency * 1000)) {
-                       printk(KERN_DEBUG "Invalid encoded frequency\n");
-                       result = -EINVAL;
-                       goto err_unreg;
+               if (p.states[i].core_frequency > p.states[0].core_frequency) {
+                       dprintk("P%u has larger frequency (%u) than P0 (%u), skipping\n", i,
+                               p.states[i].core_frequency, p.states[0].core_frequency);
+                       p.states[i].core_frequency = 0;
+                       continue;
                }
        }
 
-       centrino_model = kmalloc(sizeof(struct cpu_model), GFP_KERNEL);
-       if (!centrino_model) {
+       centrino_model[cpu] = kmalloc(sizeof(struct cpu_model), GFP_KERNEL);
+       if (!centrino_model[cpu]) {
                result = -ENOMEM;
                goto err_unreg;
        }
-       memset(centrino_model, 0, sizeof(struct cpu_model));
+       memset(centrino_model[cpu], 0, sizeof(struct cpu_model));
 
-       centrino_model->model_name=NULL;
-       centrino_model->max_freq = p.states[0].core_frequency * 1000;
-       centrino_model->op_points =  kmalloc(sizeof(struct cpufreq_frequency_table) * 
+       centrino_model[cpu]->model_name=NULL;
+       centrino_model[cpu]->max_freq = p.states[0].core_frequency * 1000;
+       centrino_model[cpu]->op_points =  kmalloc(sizeof(struct cpufreq_frequency_table) *
                                             (p.state_count + 1), GFP_KERNEL);
-        if (!centrino_model->op_points) {
+        if (!centrino_model[cpu]->op_points) {
                 result = -ENOMEM;
                 goto err_kfree;
         }
 
-       cur_freq = get_cur_freq(0);
-
         for (i=0; i<p.state_count; i++) {
-               centrino_model->op_points[i].index = p.states[i].control;
-               centrino_model->op_points[i].frequency = p.states[i].core_frequency * 1000;
-               if (cur_freq == centrino_model->op_points[i].frequency)
+               centrino_model[cpu]->op_points[i].index = p.states[i].control;
+               centrino_model[cpu]->op_points[i].frequency = p.states[i].core_frequency * 1000;
+               dprintk("adding state %i with frequency %u and control value %04x\n", 
+                       i, centrino_model[cpu]->op_points[i].frequency, centrino_model[cpu]->op_points[i].index);
+       }
+       centrino_model[cpu]->op_points[p.state_count].frequency = CPUFREQ_TABLE_END;
+
+       cur_freq = get_cur_freq(cpu);
+
+       for (i=0; i<p.state_count; i++) {
+               if (!p.states[i].core_frequency) {
+                       dprintk("skipping state %u\n", i);
+                       centrino_model[cpu]->op_points[i].frequency = CPUFREQ_ENTRY_INVALID;
+                       continue;
+               }
+               
+               if (extract_clock(centrino_model[cpu]->op_points[i].index, cpu, 0) !=
+                   (centrino_model[cpu]->op_points[i].frequency)) {
+                       dprintk("Invalid encoded frequency (%u vs. %u)\n",
+                               extract_clock(centrino_model[cpu]->op_points[i].index, cpu, 0),
+                               centrino_model[cpu]->op_points[i].frequency);
+                       result = -EINVAL;
+                       goto err_kfree_all;
+               }
+
+               if (cur_freq == centrino_model[cpu]->op_points[i].frequency)
                        p.state = i;
        }
-       centrino_model->op_points[p.state_count].frequency = CPUFREQ_TABLE_END;
+
+       /* notify BIOS that we exist */
+       acpi_processor_notify_smm(THIS_MODULE);
 
        return 0;
 
+ err_kfree_all:
+       kfree(centrino_model[cpu]->op_points);
  err_kfree:
-       kfree(centrino_model);
+       kfree(centrino_model[cpu]);
  err_unreg:
-       acpi_processor_unregister_performance(&p, 0);
+       acpi_processor_unregister_performance(&p, cpu);
+       dprintk(KERN_INFO PFX "invalid ACPI data\n");
        return (result);
 }
 #else
@@ -392,21 +486,34 @@ static int centrino_cpu_init(struct cpufreq_policy *policy)
        unsigned freq;
        unsigned l, h;
        int ret;
+       int i;
 
-       if (policy->cpu != 0)
+       /* Only Intel makes Enhanced Speedstep-capable CPUs */
+       if (cpu->x86_vendor != X86_VENDOR_INTEL || !cpu_has(cpu, X86_FEATURE_EST))
                return -ENODEV;
 
-       if (!cpu_has(cpu, X86_FEATURE_EST))
-               return -ENODEV;
+       for (i = 0; i < N_IDS; i++)
+               if (centrino_verify_cpu_id(cpu, &cpu_ids[i]))
+                       break;
 
-       if ((centrino_verify_cpu_id(cpu, &cpu_id_banias)) &&
-           (centrino_verify_cpu_id(cpu, &cpu_id_dothan_a1))) {
-               printk(KERN_INFO PFX "found unsupported CPU with Enhanced SpeedStep: "
-                      "send /proc/cpuinfo to " MAINTAINER "\n");
-               return -ENODEV;
+       if (i != N_IDS)
+               centrino_cpu[policy->cpu] = &cpu_ids[i];
+
+       if (is_const_loops_cpu(policy->cpu)) {
+               centrino_driver.flags |= CPUFREQ_CONST_LOOPS;
        }
 
        if (centrino_cpu_init_acpi(policy)) {
+               if (policy->cpu != 0)
+                       return -ENODEV;
+
+               if (!centrino_cpu[policy->cpu]) {
+                       dprintk(KERN_INFO PFX "found unsupported CPU with "
+                       "Enhanced SpeedStep: send /proc/cpuinfo to "
+                       MAINTAINER "\n");
+                       return -ENODEV;
+               }
+
                if (centrino_cpu_init_table(policy)) {
                        return -ENODEV;
                }
@@ -415,11 +522,12 @@ static int centrino_cpu_init(struct cpufreq_policy *policy)
        /* 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);
+               dprintk("trying to enable Enhanced SpeedStep (%x)\n", l);
                wrmsr(MSR_IA32_MISC_ENABLE, l, h);
-               
+
                /* check to see if it stuck */
                rdmsr(MSR_IA32_MISC_ENABLE, l, h);
                if (!(l & (1<<16))) {
@@ -428,40 +536,42 @@ static int centrino_cpu_init(struct cpufreq_policy *policy)
                }
        }
 
-       freq = get_cur_freq(0);
+       freq = get_cur_freq(policy->cpu);
 
        policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
        policy->cpuinfo.transition_latency = 10000; /* 10uS transition latency */
        policy->cur = freq;
 
-       dprintk(KERN_INFO PFX "centrino_cpu_init: policy=%d cur=%dkHz\n",
-               policy->policy, policy->cur);
-       
-       ret = cpufreq_frequency_table_cpuinfo(policy, centrino_model->op_points);
+       dprintk("centrino_cpu_init: cur=%dkHz\n", policy->cur);
+
+       ret = cpufreq_frequency_table_cpuinfo(policy, centrino_model[policy->cpu]->op_points);
        if (ret)
                return (ret);
 
-       cpufreq_frequency_table_get_attr(centrino_model->op_points, policy->cpu);
+       cpufreq_frequency_table_get_attr(centrino_model[policy->cpu]->op_points, policy->cpu);
 
        return 0;
 }
 
 static int centrino_cpu_exit(struct cpufreq_policy *policy)
 {
-       if (!centrino_model)
+       unsigned int cpu = policy->cpu;
+
+       if (!centrino_model[cpu])
                return -ENODEV;
 
-       cpufreq_frequency_table_put_attr(policy->cpu);
+       cpufreq_frequency_table_put_attr(cpu);
 
 #ifdef CONFIG_X86_SPEEDSTEP_CENTRINO_ACPI
-       if (!centrino_model->model_name) {
-               acpi_processor_unregister_performance(&p, 0);
-               kfree(centrino_model->op_points);
-               kfree(centrino_model);
+       if (!centrino_model[cpu]->model_name) {
+               dprintk("unregistering and freeing ACPI data\n");
+               acpi_processor_unregister_performance(&p, cpu);
+               kfree(centrino_model[cpu]->op_points);
+               kfree(centrino_model[cpu]);
        }
 #endif
 
-       centrino_model = NULL;
+       centrino_model[cpu] = NULL;
 
        return 0;
 }
@@ -475,7 +585,7 @@ static int centrino_cpu_exit(struct cpufreq_policy *policy)
  */
 static int centrino_verify (struct cpufreq_policy *policy)
 {
-       return cpufreq_frequency_table_verify(policy, centrino_model->op_points);
+       return cpufreq_frequency_table_verify(policy, centrino_model[policy->cpu]->op_points);
 }
 
 /**
@@ -491,54 +601,63 @@ static int centrino_target (struct cpufreq_policy *policy,
                            unsigned int relation)
 {
        unsigned int    newstate = 0;
-       unsigned int    msr, oldmsr, h;
+       unsigned int    msr, oldmsr, h, cpu = policy->cpu;
        struct cpufreq_freqs    freqs;
+       cpumask_t               saved_mask;
+       int                     retval;
 
-       if (centrino_model == NULL)
+       if (centrino_model[cpu] == NULL)
                return -ENODEV;
 
-       if (cpufreq_frequency_table_target(policy, centrino_model->op_points, target_freq,
-                                          relation, &newstate))
-               return -EINVAL;
+       /*
+        * Support for SMP systems.
+        * Make sure we are running on the CPU that wants to change frequency
+        */
+       saved_mask = current->cpus_allowed;
+       set_cpus_allowed(current, policy->cpus);
+       if (!cpu_isset(smp_processor_id(), policy->cpus)) {
+               dprintk("couldn't limit to CPUs in this domain\n");
+               return(-EAGAIN);
+       }
 
-       msr = centrino_model->op_points[newstate].index;
+       if (cpufreq_frequency_table_target(policy, centrino_model[cpu]->op_points, target_freq,
+                                          relation, &newstate)) {
+               retval = -EINVAL;
+               goto migrate_end;
+       }
+
+       msr = centrino_model[cpu]->op_points[newstate].index;
        rdmsr(MSR_IA32_PERF_CTL, oldmsr, h);
 
-       if (msr == (oldmsr & 0xffff))
-               return 0;
+       if (msr == (oldmsr & 0xffff)) {
+               retval = 0;
+               dprintk("no change needed - msr was and needs to be %x\n", oldmsr);
+               goto migrate_end;
+       }
+
+       freqs.cpu = cpu;
+       freqs.old = extract_clock(oldmsr, cpu, 0);
+       freqs.new = extract_clock(msr, cpu, 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",
+       dprintk("target=%dkHz old=%d new=%d msr=%04x\n",
                target_freq, freqs.old, freqs.new, msr);
 
-       cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);   
+       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;
+       retval = 0;
+migrate_end:
+       set_cpus_allowed(current, saved_mask);
+       return (retval);
 }
 
 static struct freq_attr* centrino_attr[] = {
@@ -547,12 +666,12 @@ static struct freq_attr* centrino_attr[] = {
 };
 
 static struct cpufreq_driver centrino_driver = {
-       .name           = "centrino", /* should be speedstep-centrino, 
+       .name           = "centrino", /* should be speedstep-centrino,
                                         but there's a 16 char limit */
        .init           = centrino_cpu_init,
        .exit           = centrino_cpu_exit,
-       .verify         = centrino_verify,
-       .target         = centrino_target,
+       .verify         = centrino_verify,
+       .target         = centrino_target,
        .get            = get_cur_freq,
        .attr           = centrino_attr,
        .owner          = THIS_MODULE,