From c86c7fbc829e27e2a4093f98ded9fbd75e515adb Mon Sep 17 00:00:00 2001
From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Date: Mon, 3 Dec 2007 17:17:10 +0100
Subject: [PATCH] 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>
---
 arch/x86/kernel/hpet.c      | 14 ++++++++++++++
 arch/x86/kernel/reboot_32.c |  4 ++++
 arch/x86/kernel/reboot_64.c |  4 ++++
 include/asm-x86/hpet.h      |  1 +
 4 files changed, 23 insertions(+)

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 53303f2e54..4a86ffd67e 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 9e2269d009..bb1a0f889c 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 71b13c5f58..53620a92a8 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();
diff --git a/include/asm-x86/hpet.h b/include/asm-x86/hpet.h
index b1f3c1ea55..ad8d6e7587 100644
--- a/include/asm-x86/hpet.h
+++ b/include/asm-x86/hpet.h
@@ -61,6 +61,7 @@ extern unsigned long force_hpet_address;
 extern int hpet_force_user;
 extern int is_hpet_enabled(void);
 extern int hpet_enable(void);
+extern void hpet_disable(void);
 extern unsigned long hpet_readl(unsigned long a);
 extern void force_hpet_resume(void);
 
-- 
2.39.5