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authorLinus Torvalds <torvalds@linux-foundation.org>2012-01-11 19:13:40 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-11 19:13:40 -0800
commit9fc5c3e3237e02a94f41cd1d2b4291593d29791d (patch)
treec8823725b10bd4d36e9311ea392dfdecb4db7974 /init
parent541048a1d31399ccdda27346a37eae4a2ad55186 (diff)
parent7c9c3a1e5fc8728e948b8fa3cbcfcfb86db3afda (diff)
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Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/intel config: Fix the APB_TIMER selection x86/mrst: Add additional debug prints for pb_keys x86/intel config: Revamp configuration to allow for Moorestown and Medfield x86/intel/scu/ipc: Match the changes in the x86 configuration x86/apb: Fix configuration constraints x86: Fix INTEL_MID silly x86/Kconfig: Cyclone-timer depends on x86-summit x86: Reduce clock calibration time during slave cpu startup x86/config: Revamp configuration for MID devices x86/sfi: Kill the IRQ as id hack
Diffstat (limited to 'init')
-rw-r--r--init/calibrate.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/init/calibrate.c b/init/calibrate.c
index 24df7976816..5f117ca9e06 100644
--- a/init/calibrate.c
+++ b/init/calibrate.c
@@ -246,6 +246,19 @@ recalibrate:
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;
@@ -265,6 +278,8 @@ 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 "