1 files changed, 32 insertions, 28 deletions

diff --git a/init/calibrate.c b/init/calibrate.c
index ecb3822d4f70..7963e3fc51d9 100644
--- a/init/calibrate.c
+++ b/init/calibrate.c
@@ -8,7 +8,9 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/timex.h>
+#include <linux/smp.h>
 
+unsigned long lpj_fine;
 unsigned long preset_lpj;
 static int __init lpj_setup(char *str)
 {
@@ -33,9 +35,9 @@ static unsigned long __cpuinit calibrate_delay_direct(void)
         unsigned long pre_start, start, post_start;
         unsigned long pre_end, end, post_end;
         unsigned long start_jiffies;
-        unsigned long tsc_rate_min, tsc_rate_max;
-        unsigned long good_tsc_sum = 0;
-        unsigned long good_tsc_count = 0;
+        unsigned long timer_rate_min, timer_rate_max;
+        unsigned long good_timer_sum = 0;
+        unsigned long good_timer_count = 0;
         int i;
 
         if (read_current_timer(&pre_start) < 0 )
@@ -79,22 +81,24 @@ static unsigned long __cpuinit calibrate_delay_direct(void)
                 }
                 read_current_timer(&post_end);
 
-                tsc_rate_max = (post_end - pre_start) / DELAY_CALIBRATION_TICKS;
-                tsc_rate_min = (pre_end - post_start) / DELAY_CALIBRATION_TICKS;
+                timer_rate_max = (post_end - pre_start) /
+                                        DELAY_CALIBRATION_TICKS;
+                timer_rate_min = (pre_end - post_start) /
+                                        DELAY_CALIBRATION_TICKS;
 
                 /*
-                 * If the upper limit and lower limit of the tsc_rate is
+                 * If the upper limit and lower limit of the timer_rate is
                  * >= 12.5% apart, redo calibration.
                  */
                 if (pre_start != 0 && pre_end != 0 &&
-                    (tsc_rate_max - tsc_rate_min) < (tsc_rate_max >> 3)) {
-                        good_tsc_count++;
-                        good_tsc_sum += tsc_rate_max;
+                    (timer_rate_max - timer_rate_min) < (timer_rate_max >> 3)) {
+                        good_timer_count++;
+                        good_timer_sum += timer_rate_max;
                 }
         }
 
-        if (good_tsc_count)
-                return (good_tsc_sum/good_tsc_count);
+        if (good_timer_count)
+                return (good_timer_sum/good_timer_count);
 
         printk(KERN_WARNING "calibrate_delay_direct() failed to get a good "
                "estimate for loops_per_jiffy.\nProbably due to long platform interrupts. Consider using \"lpj=\" boot option.\n");
@@ -108,6 +112,10 @@ static unsigned long __cpuinit calibrate_delay_direct(void) {return 0;}
  * This is the number of bits of precision for the loops_per_jiffy.  Each
  * bit takes on average 1.5/HZ seconds.  This (like the original) is a little
  * better than 1%
+ * For the boot cpu we can skip the delay calibration and assign it a value
+ * calculated based on the timer frequency.
+ * For the rest of the CPUs we cannot assume that the timer frequency is same as
+ * the cpu frequency, hence do the calibration for those.
  */
 #define LPS_PREC 8
 
@@ -118,20 +126,20 @@ void __cpuinit calibrate_delay(void)
 
         if (preset_lpj) {
                 loops_per_jiffy = preset_lpj;
-                printk("Calibrating delay loop (skipped)... "
-                        "%lu.%02lu BogoMIPS preset\n",
-                        loops_per_jiffy/(500000/HZ),
-                        (loops_per_jiffy/(5000/HZ)) % 100);
+                printk(KERN_INFO
+                        "Calibrating delay loop (skipped) preset value.. ");
+        } else if ((smp_processor_id() == 0) && lpj_fine) {
+                loops_per_jiffy = lpj_fine;
+                printk(KERN_INFO
+                        "Calibrating delay loop (skipped), "
+                        "value calculated using timer frequency.. ");
         } else if ((loops_per_jiffy = calibrate_delay_direct()) != 0) {
-                printk("Calibrating delay using timer specific routine.. ");
-                printk("%lu.%02lu BogoMIPS (lpj=%lu)\n",
-                        loops_per_jiffy/(500000/HZ),
-                        (loops_per_jiffy/(5000/HZ)) % 100,
-                        loops_per_jiffy);
+                printk(KERN_INFO
+                        "Calibrating delay using timer specific routine.. ");
         } else {
                 loops_per_jiffy = (1<<12);
 
-                printk(KERN_DEBUG "Calibrating delay loop... ");
+                printk(KERN_INFO "Calibrating delay loop... ");
                 while ((loops_per_jiffy <<= 1) != 0) {
                         /* wait for "start of" clock tick */
                         ticks = jiffies;
@@ -161,12 +169,8 @@ void __cpuinit calibrate_delay(void)
                         if (jiffies != ticks)   /* longer than 1 tick */
                                 loops_per_jiffy &= ~loopbit;
                 }
-
-                /* Round the value and print it */
-                printk("%lu.%02lu BogoMIPS (lpj=%lu)\n",
-                        loops_per_jiffy/(500000/HZ),
-                        (loops_per_jiffy/(5000/HZ)) % 100,
-                        loops_per_jiffy);
         }
-
+        printk(KERN_INFO "%lu.%02lu BogoMIPS (lpj=%lu)\n",
+                        loops_per_jiffy/(500000/HZ),
+                        (loops_per_jiffy/(5000/HZ)) % 100, loops_per_jiffy);
 }