x86: disable hpet on shutdown

If HPET was enabled by pci quirks, we use i8253 as initial clockevent
because pci quirks doesn't run until pci is initialized.

The above means the kernel (or something) is assuming HPET legacy
replacement is disabled and can use i8253 at boot.

If we used kexec, it isn't true. So, this patch disables HPET legacy
replacement for kexec in machine_shutdown().

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

3 files changed, 22 insertions, 0 deletions

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 53303f2e5475..4a86ffd67ec5 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -446,6 +446,20 @@ static __init int hpet_late_init(void)
 }
 fs_initcall(hpet_late_init);
 
+void hpet_disable(void)
+{
+        if (is_hpet_capable()) {
+                unsigned long cfg = hpet_readl(HPET_CFG);
+
+                if (hpet_legacy_int_enabled) {
+                        cfg &= ~HPET_CFG_LEGACY;
+                        hpet_legacy_int_enabled = 0;
+                }
+                cfg &= ~HPET_CFG_ENABLE;
+                hpet_writel(cfg, HPET_CFG);
+        }
+}
+
 #ifdef CONFIG_HPET_EMULATE_RTC
 
 /* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET
diff --git a/arch/x86/kernel/reboot_32.c b/arch/x86/kernel/reboot_32.c
index 9e2269d00918..bb1a0f889c5e 100644
--- a/arch/x86/kernel/reboot_32.c
+++ b/arch/x86/kernel/reboot_32.c
@@ -11,6 +11,7 @@
 #include <linux/reboot.h>
 #include <asm/uaccess.h>
 #include <asm/apic.h>
+#include <asm/hpet.h>
 #include <asm/desc.h>
 #include "mach_reboot.h"
 #include <asm/reboot_fixups.h>
@@ -326,6 +327,9 @@ static void native_machine_shutdown(void)
 #ifdef CONFIG_X86_IO_APIC
         disable_IO_APIC();
 #endif
+#ifdef CONFIG_HPET_TIMER
+        hpet_disable();
+#endif
 }
 
 void __attribute__((weak)) mach_reboot_fixups(void)
diff --git a/arch/x86/kernel/reboot_64.c b/arch/x86/kernel/reboot_64.c
index 71b13c5f5817..53620a92a8fd 100644
--- a/arch/x86/kernel/reboot_64.c
+++ b/arch/x86/kernel/reboot_64.c
@@ -17,6 +17,7 @@
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/apic.h>
+#include <asm/hpet.h>
 #include <asm/gart.h>
 
 /*
@@ -113,6 +114,9 @@ void machine_shutdown(void)
 
         disable_IO_APIC();
 
+#ifdef CONFIG_HPET_TIMER
+        hpet_disable();
+#endif
         local_irq_restore(flags);
 
         pci_iommu_shutdown();