Commit af5a1dad authored Jun 23, 2019 by Thomas Gleixner

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

parent 9e16e493

arch/x86/kernel/hpet.c

+17 −0

Original line number	Diff line number	Diff line
		@@ -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 */

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