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authorThomas Gleixner <tglx@linutronix.de>2019-06-23 15:24:01 +0200
committerThomas Gleixner <tglx@linutronix.de>2019-06-28 00:57:23 +0200
commitaf5a1dadf3fcf673906af1a1129b2b7528494ee5 (patch)
treebe1ada03a31b6772eb5688f61c9297dc76ca3abb /arch/x86/kernel/hpet.c
parent9e16e4933e48819a259b8967e72e5765349953b1 (diff)
x86/hpet: Add function to select a /dev/hpet channel
If CONFIG_HPET=y is enabled the x86 specific HPET code should reserve at least one channel for the /dev/hpet character device, so that not all channels are absorbed for per CPU clockevent devices. Create a function to assign HPET_MODE_DEVICE so the rework of the clockevents allocation code can utilize the mode information instead of reducing the number of evaluated channels by #ifdef hackery. The function is not yet used, but provided as a separate patch for ease of review. It will be used when the rework of the clockevent selection takes place. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Andi Kleen <andi.kleen@intel.com> Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com> Cc: Stephane Eranian <eranian@google.com> Cc: Ravi Shankar <ravi.v.shankar@intel.com> Link: https://lkml.kernel.org/r/20190623132436.002758910@linutronix.de
Diffstat (limited to 'arch/x86/kernel/hpet.c')
-rw-r--r--arch/x86/kernel/hpet.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 3a8ec363d569..640ff75cc523 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -228,8 +228,25 @@ static void __init hpet_reserve_platform_timers(void)
hpet_alloc(&hd);
}
+
+static void __init hpet_select_device_channel(void)
+{
+ int i;
+
+ for (i = 0; i < hpet_base.nr_channels; i++) {
+ struct hpet_channel *hc = hpet_base.channels + i;
+
+ /* Associate the first unused channel to /dev/hpet */
+ if (hc->mode == HPET_MODE_UNUSED) {
+ hc->mode = HPET_MODE_DEVICE;
+ return;
+ }
+ }
+}
+
#else
static inline void hpet_reserve_platform_timers(void) { }
+static inline void hpet_select_device_channel(void) {}
#endif
/* Common HPET functions */