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authorIngo Molnar <mingo@kernel.org>2012-04-13 09:50:21 +0200
committerIngo Molnar <mingo@kernel.org>2012-04-13 09:50:21 +0200
commit659c36fcda403013a01b85da07cf2d9711e6d6c7 (patch)
treeece2e7d0e2c19ea5a3d0ec172ad0b81a8a19021d /arch/arm/mach-ebsa110/core.c
parent9521d830b6341d1887dcfc2aebde23fbfa5f1473 (diff)
parent5a7ed29c7572d00a75e8c4529e30c5ac2ef82271 (diff)
Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core
Fixes and improvements for perf/core: . Overhaul the tools/ makefiles, gluing them to the top level Makefile, from Borislav Petkov. . Move the UI files from tools/perf/util/ui/ to tools/perf/ui/. Also move the GTK+ browser to tools/perf/ui/gtk/, from Namhyung Kim. . Only fallback to sw cycles counter on ENOENT for the hw cycles, from Robert Richter . Trivial fixes from Robert Richter . Handle the autogenerated bison/flex files better, from Namhyung and Jiri Olsa. . Navigate jump instructions in the annotate browser, just press enter or ->, still needs support for a jump navigation history, i.e. to go back. . Search string in the annotate browser: same keys as vim: / forward n next backward/forward ? backward . Clarify number of events/samples in the report header, from Ashay Rane Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/arm/mach-ebsa110/core.c')
-rw-r--r--arch/arm/mach-ebsa110/core.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/arm/mach-ebsa110/core.c b/arch/arm/mach-ebsa110/core.c
index 294aad07f7a..804c9122b7b 100644
--- a/arch/arm/mach-ebsa110/core.c
+++ b/arch/arm/mach-ebsa110/core.c
@@ -271,8 +271,33 @@ static struct platform_device *ebsa110_devices[] = {
&am79c961_device,
};
+/*
+ * EBSA110 idling methodology:
+ *
+ * We can not execute the "wait for interrupt" instruction since that
+ * will stop our MCLK signal (which provides the clock for the glue
+ * logic, and therefore the timer interrupt).
+ *
+ * Instead, we spin, polling the IRQ_STAT register for the occurrence
+ * of any interrupt with core clock down to the memory clock.
+ */
+static void ebsa110_idle(void)
+{
+ const char *irq_stat = (char *)0xff000000;
+
+ /* disable clock switching */
+ asm volatile ("mcr p15, 0, ip, c15, c2, 2" : : : "cc");
+
+ /* wait for an interrupt to occur */
+ while (!*irq_stat);
+
+ /* enable clock switching */
+ asm volatile ("mcr p15, 0, ip, c15, c1, 2" : : : "cc");
+}
+
static int __init ebsa110_init(void)
{
+ arm_pm_idle = ebsa110_idle;
return platform_add_devices(ebsa110_devices, ARRAY_SIZE(ebsa110_devices));
}