[CPUFREQ] powernow-k7: fix MHz rounding issue with perflib

[linux-2.6-omap-h63xx.git] / arch / i386 / kernel / cpu / cpufreq / powernow-k7.c

diff --git a/arch/i386/kernel/cpu/cpufreq/powernow-k7.c b/arch/i386/kernel/cpu/cpufreq/powernow-k7.c
index 694d4793bf6ae5f1aaf1bddae150e958f572fecf..ca3e1d341889dfc00964fd2d052e13d9108d8562 100644 (file)
--- a/arch/i386/kernel/cpu/cpufreq/powernow-k7.c
+++ b/arch/i386/kernel/cpu/cpufreq/powernow-k7.c
@@ -12,7 +12,6 @@
  * - We disable half multipliers if ACPI is used on A0 stepping CPUs.
  */
 
-#include <linux/config.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
@@ -69,7 +68,7 @@ union powernow_acpi_control_t {
 
 #ifdef CONFIG_CPU_FREQ_DEBUG
 /* divide by 1000 to get VCore voltage in V. */
-static int mobile_vid_table[32] = {
+static const int mobile_vid_table[32] = {
     2000, 1950, 1900, 1850, 1800, 1750, 1700, 1650,
     1600, 1550, 1500, 1450, 1400, 1350, 1300, 0,
     1275, 1250, 1225, 1200, 1175, 1150, 1125, 1100,
@@ -78,7 +77,7 @@ static int mobile_vid_table[32] = {
 #endif
 
 /* divide by 10 to get FID. */
-static int fid_codes[32] = {
+static const int fid_codes[32] = {
     110, 115, 120, 125, 50, 55, 60, 65,
     70, 75, 80, 85, 90, 95, 100, 105,
     30, 190, 40, 200, 130, 135, 140, 210,
@@ -342,15 +341,17 @@ static int powernow_acpi_init(void)
        pc.val = (unsigned long) acpi_processor_perf->states[0].control;
        for (i = 0; i < number_scales; i++) {
                u8 fid, vid;
-               unsigned int speed;
+               struct acpi_processor_px *state =
+                       &acpi_processor_perf->states[i];
+               unsigned int speed, speed_mhz;
 
-               pc.val = (unsigned long) acpi_processor_perf->states[i].control;
+               pc.val = (unsigned long) state->control;
                dprintk ("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
                         i,
-                        (u32) acpi_processor_perf->states[i].core_frequency,
-                        (u32) acpi_processor_perf->states[i].power,
-                        (u32) acpi_processor_perf->states[i].transition_latency,
-                        (u32) acpi_processor_perf->states[i].control,
+                        (u32) state->core_frequency,
+                        (u32) state->power,
+                        (u32) state->transition_latency,
+                        (u32) state->control,
                         pc.bits.sgtc);
 
                vid = pc.bits.vid;
@@ -361,6 +362,18 @@ static int powernow_acpi_init(void)
                powernow_table[i].index |= (vid << 8); /* upper 8 bits */
 
                speed = powernow_table[i].frequency;
+               speed_mhz = speed / 1000;
+
+               /* processor_perflib will multiply the MHz value by 1000 to
+                * get a KHz value (e.g. 1266000). However, powernow-k7 works
+                * with true KHz values (e.g. 1266768). To ensure that all
+                * powernow frequencies are available, we must ensure that
+                * ACPI doesn't restrict them, so we round up the MHz value
+                * to ensure that perflib's computed KHz value is greater than
+                * or equal to powernow's KHz value.
+                */
+               if (speed % 1000 > 0)
+                       speed_mhz++;
 
                if ((fid_codes[fid] % 10)==5) {
                        if (have_a0 == 1)
@@ -369,10 +382,16 @@ static int powernow_acpi_init(void)
 
                dprintk ("   FID: 0x%x (%d.%dx [%dMHz])  "
                         "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
-                        fid_codes[fid] % 10, speed/1000, vid,
+                        fid_codes[fid] % 10, speed_mhz, vid,
                         mobile_vid_table[vid]/1000,
                         mobile_vid_table[vid]%1000);
 
+               if (state->core_frequency != speed_mhz) {
+                       state->core_frequency = speed_mhz;
+                       dprintk("   Corrected ACPI frequency to %d\n",
+                               speed_mhz);
+               }
+
                if (latency < pc.bits.sgtc)
                        latency = pc.bits.sgtc;
 
@@ -603,7 +622,7 @@ static int __init powernow_cpu_init (struct cpufreq_policy *policy)
                        result = powernow_acpi_init();
                        if (result) {
                                printk (KERN_INFO PFX "ACPI and legacy methods failed\n");
-                               printk (KERN_INFO PFX "See http://www.codemonkey.org.uk/projects/cpufreq/powernow-k7.shtml\n");
+                               printk (KERN_INFO PFX "See http://www.codemonkey.org.uk/projects/cpufreq/powernow-k7.html\n");
                        }
                } else {
                        /* SGTC use the bus clock as timer */