x86/intel: Add quirk to disable HPET for the Baytrail platform

HPET on current Baytrail platform has accuracy problem to be
used as reliable clocksource/clockevent, so add a early quirk to
disable it.

Signed-off-by: Feng Tang <feng.tang@intel.com>
Cc: Clemens Ladisch <clemens@ladisch.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1398327498-13163-2-git-send-email-feng.tang@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/early-quirks.c

@@ -17,6 +17,7 @@
 #include <asm/dma.h>
 #include <asm/io_apic.h>
 #include <asm/apic.h>
+#include <asm/hpet.h>
 #include <asm/iommu.h>
 #include <asm/gart.h>
 #include <asm/irq_remapping.h>
@@ -530,6 +531,15 @@ static void __init intel_graphics_stolen(int num, int slot, int func)
 	}
 }
 
+static void __init force_disable_hpet(int num, int slot, int func)
+{
+#ifdef CONFIG_HPET_TIMER
+	boot_hpet_disable = 1;
+	pr_info("x86/hpet: Will disable the HPET for this platform because it's not reliable\n");
+#endif
+}
+
+
 #define QFLAG_APPLY_ONCE 	0x1
 #define QFLAG_APPLIED		0x2
 #define QFLAG_DONE		(QFLAG_APPLY_ONCE|QFLAG_APPLIED)
@@ -567,6 +577,12 @@ static struct chipset early_qrk[] __initdata = {
 	  PCI_BASE_CLASS_BRIDGE, 0, intel_remapping_check },
 	{ PCI_VENDOR_ID_INTEL, PCI_ANY_ID, PCI_CLASS_DISPLAY_VGA, PCI_ANY_ID,
 	  QFLAG_APPLY_ONCE, intel_graphics_stolen },
+	/*
+	 * HPET on current version of Baytrail platform has accuracy
+	 * problems, disable it for now:
+	 */
+	{ PCI_VENDOR_ID_INTEL, 0x0f00,
+		PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, force_disable_hpet},
 	{}
 };