#include <linux/init.h>
#include <linux/timex.h>
#include <linux/smp.h>
+#include <linux/percpu.h>
unsigned long lpj_fine;
unsigned long preset_lpj;
return lpj;
}
+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)) __cpuinit calibrate_delay_is_known(void)
+{
+ return 0;
+}
+
void __cpuinit 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);
+ 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) "
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 "
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),