diff options
Diffstat (limited to 'init/calibrate.c')
| -rw-r--r-- | init/calibrate.c | 38 |
1 files changed, 33 insertions, 5 deletions
diff --git a/init/calibrate.c b/init/calibrate.c index aae2f40fea4..520702db9ac 100644 --- a/init/calibrate.c +++ b/init/calibrate.c @@ -9,6 +9,7 @@ #include <linux/init.h> #include <linux/timex.h> #include <linux/smp.h> +#include <linux/percpu.h> unsigned long lpj_fine; unsigned long preset_lpj; @@ -30,7 +31,7 @@ __setup("lpj=", lpj_setup); #define DELAY_CALIBRATION_TICKS ((HZ < 100) ? 1 : (HZ/100)) #define MAX_DIRECT_CALIBRATION_RETRIES 5 -static unsigned long __cpuinit calibrate_delay_direct(void) +static unsigned long calibrate_delay_direct(void) { unsigned long pre_start, start, post_start; unsigned long pre_end, end, post_end; @@ -165,7 +166,10 @@ static unsigned long __cpuinit calibrate_delay_direct(void) return 0; } #else -static unsigned long __cpuinit calibrate_delay_direct(void) {return 0;} +static unsigned long calibrate_delay_direct(void) +{ + return 0; +} #endif /* @@ -179,7 +183,7 @@ static unsigned long __cpuinit calibrate_delay_direct(void) {return 0;} */ #define LPS_PREC 8 -static unsigned long __cpuinit calibrate_delay_converge(void) +static unsigned long calibrate_delay_converge(void) { /* First stage - slowly accelerate to find initial bounds */ unsigned long lpj, lpj_base, ticks, loopadd, loopadd_base, chop_limit; @@ -243,12 +247,33 @@ recalibrate: return lpj; } -void __cpuinit calibrate_delay(void) +static DEFINE_PER_CPU(unsigned long, cpu_loops_per_jiffy) = { 0 }; + +/* + * Check if cpu calibration delay is already known. For example, + * some processors with multi-core sockets may have all cores + * with the same calibration delay. + * + * Architectures should override this function if a faster calibration + * method is available. + */ +unsigned long __attribute__((weak)) calibrate_delay_is_known(void) +{ + return 0; +} + +void calibrate_delay(void) { unsigned long lpj; static bool printed; + int this_cpu = smp_processor_id(); - if (preset_lpj) { + if (per_cpu(cpu_loops_per_jiffy, this_cpu)) { + lpj = per_cpu(cpu_loops_per_jiffy, this_cpu); + if (!printed) + pr_info("Calibrating delay loop (skipped) " + "already calibrated this CPU"); + } else if (preset_lpj) { lpj = preset_lpj; if (!printed) pr_info("Calibrating delay loop (skipped) " @@ -257,6 +282,8 @@ void __cpuinit calibrate_delay(void) lpj = lpj_fine; pr_info("Calibrating delay loop (skipped), " "value calculated using timer frequency.. "); + } else if ((lpj = calibrate_delay_is_known())) { + ; } else if ((lpj = calibrate_delay_direct()) != 0) { if (!printed) pr_info("Calibrating delay using timer " @@ -266,6 +293,7 @@ void __cpuinit calibrate_delay(void) pr_info("Calibrating delay loop... "); lpj = calibrate_delay_converge(); } + per_cpu(cpu_loops_per_jiffy, this_cpu) = lpj; if (!printed) pr_cont("%lu.%02lu BogoMIPS (lpj=%lu)\n", lpj/(500000/HZ), |