HPET : Legacy Route replacement patch.

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HI,
This patch enables the legacy routing replacement capabilities of the HPET.

HPET spec is available at www.intel.com/technology/architecture/hpetspec.htm

Background : HPET is capable of replacing the IRQ0 (connected INT0
PIN) timer interrupt. The capability register (at offset 0 of HPET
base address) has a bit specifying if HPET chip is capbale of doing
this. OS can read the bit either from HW or ACPI table. (HPET ACPI
description table -> Event Timer block -> bit 15, page 30 of HPET
spec).  Ideally, I think BIOS should set the ACPI table than letting
the OS read H/W, which gives the BIOS a way to configure either legacy
or Legacy replacement modes.

But a number of bioses (both phoenix and AMI) are not working as
expected. So I have provided a command line parameter which overrides
the BIOS ACPI entry. So, irrespctive of the BIOS' HPET ACPI Descriptor
table settings, if the parameter hpet_lrr=[0,1] is specified, it takes
precedence.

It seems, some other chipsets (CK-804) has a timing problem, as a
result of which the machine hangs. In this case, I have passed the
parameter lpj=<approx bogomips value * 500> which solves this issue. I
am investigating into this further and would try fixing it.

Even though compile tested, on 2.6.19-XX I have not tested this patch.
I ran this on 2.6.16-rc5, which is the latest version that runs on my
machine (sunfire 4600).

Patch here...

Signed-off-by: Om Narasimhan <[email protected]>

----

arch/i386/kernel/acpi/boot.c |   13 +++++++++++++
arch/i386/kernel/time_hpet.c |    3 ++-
arch/x86_64/kernel/time.c    |   15 +++++++++++++--
include/asm-x86_64/hpet.h    |    1 +
include/linux/acpi.h         |    1 +
5 files changed, 30 insertions(+), 3 deletions(-)
arch/i386/kernel/acpi/boot.c |   13 +++++++++++++
arch/i386/kernel/time_hpet.c |    3 ++-
arch/x86_64/kernel/time.c    |   15 +++++++++++++--
include/asm-x86_64/hpet.h    |    1 +
include/linux/acpi.h         |    1 +
5 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index ab974ff..228d2b5 100644
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -82,6 +82,15 @@ EXPORtested  T_SYMBOL(acpi_strict);
acpi_interrupt_flags acpi_sci_flags __initdata;
int acpi_sci_override_gsi __initdata;
int acpi_skip_timer_override __initdata;
+int acpi_hpet_lrr;	/* the HPET Legacy routing replacement option
passed through ACPI Table */
+int hpet_lrr_force;	/* cmdlinetested  opt. for faulty bioses not
setting ACPI HPET entry right */
+
+static int hpet_lrr_setup (char *str)
+{
+	get_option(&str,&hpet_lrr_force);
+	return 1;
+}
+__setup ("hpet_lrr=", hpet_lrr_setup);

#ifdef CONFIG_X86_LOCAL_APIC
static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
@@ -669,6 +678,10 @@ #define HPET_RESOURCE_NAME_SIZE 9
			 "HPET %u", hpet_tbl->number);
		hpet_res->end = (1 * 1024) - 1;
	}
+	acpi_hpet_lrr = (hpet_tbl->id & ACPI_HPET_LRR_CAP) ? 1 : 0;
+	/* Print a message to warn about the bios BUG if HPET ACPI is not
correctly populated */
+	printk(KERN_INFO PREFIX "HPET id: %#x. ACPI LRR bit %s SET\n",
+			hpet_tbl->id, acpi_hpet_lrr ? "": "NOT");

#ifdef	CONFIG_X86_64
	vxtime.hpet_address = hpet_tbl->addr.addrl |
diff --git a/arch/i386/kernel/time_hpet.c b/arch/i386/kernel/time_hpet.c
index 1a2a979..01b2f67 100644
--- a/arch/i386/kernel/time_hpet.c
+++ b/arch/i386/kernel/time_hpet.c
@@ -94,7 +94,8 @@ static int hpet_timer_stop_set_go(unsign
 	 * Go!
 	 */
	cfg = hpet_readl(HPET_CFG);
-	if (hpet_use_timer)
+	/* Ideally the following should be &&(acpi_hpet_lrr || hpet_lrr_force) */
+	if (hpet_use_timer && hpet_lrr_force)
		cfg |= HPET_CFG_LEGACY;
	cfg |= HPET_CFG_ENABLE;
	hpet_writel(cfg, HPET_CFG);
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 1ba5a44..3417c0f 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -48,6 +48,8 @@ static void cpufreq_delayed_get(void);
#endif
extern void i8254_timer_resume(void);
extern int using_apic_timer;
+extern int acpi_hpet_lrr;
+extern int hpet_lrr_force;

static char *timename = NULL;

@@ -783,7 +785,10 @@ static int hpet_timer_stop_set_go(unsign
		    HPET_TN_32BIT, HPET_T0_CFG);
		hpet_writel(hpet_tick, HPET_T0_CMP); /* next interrupt */
		hpet_writel(hpet_tick, HPET_T0_CMP); /* period */
-		cfg |= HPET_CFG_LEGACY;
+		/* Ideally the following should be (acpi_hpet_lrr || hpet_lrr_force) */
+		if (hpet_lrr_force)
+			cfg |= HPET_CFG_LEGACY;
+
	}
/*
 * Go!
@@ -887,6 +892,7 @@ time_cpu_notifier(struct notifier_block

void __init time_init(void)
{
+	int timer_irq = 0;
	if (nohpet)
		vxtime.hpet_address = 0;

@@ -906,6 +912,10 @@ void __init time_init(void)
	  	tick_nsec = TICK_NSEC_HPET;
		cpu_khz = hpet_calibrate_tsc();
		timename = "HPET";
+		/* Ideally the following should be (acpi_hpet_lrr || hpet_lrr_force) */
+		if (hpet_lrr_force)
+			timer_irq = HPET_TIMER_LRR_IRQ;
+
#ifdef CONFIG_X86_PM_TIMER
	} else if (pmtmr_ioport && !vxtime.hpet_address) {
		vxtime_hz = PM_TIMER_FREQUENCY;
@@ -924,7 +934,8 @@ #endif
	vxtime.tsc_quot = (USEC_PER_MSEC << US_SCALE) / cpu_khz;
	vxtime.last_tsc = get_cycles_sync();
	set_cyc2ns_scale(cpu_khz);
-	setup_irq(0, &irq0);
+	printk (KERN_WARNING PREFIX "Registering Timer IRQ = %d\n", timer_irq);
+	setup_irq(timer_irq, &irq0);
	hotcpu_notifier(time_cpu_notifier, 0);
	time_cpu_notifier(NULL, CPU_ONLINE, (void *)(long)smp_processor_id());

diff --git a/include/asm-x86_64/hpet.h b/include/asm-x86_64/hpet.h
index b390984..2d18b39 100644
--- a/include/asm-x86_64/hpet.h
+++ b/include/asm-x86_64/hpet.h
@@ -37,6 +37,7 @@ #define HPET_CFG_ENABLE	0x001
#define HPET_CFG_LEGACY	0x002
#define	HPET_LEGACY_8254	2
#define	HPET_LEGACY_RTC		8
+#define	HPET_TIMER_LRR_IRQ	2

#define HPET_TN_LEVEL		0x0002
#define HPET_TN_ENABLE		0x0004
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 2b0c955..62dab08 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -220,6 +220,7 @@ enum acpi_interrupt_id {
};

#define	ACPI_SPACE_MEM		0
+#define	ACPI_HPET_LRR_CAP	0x8000

struct acpi_gen_regaddr {
	u8  space_id;
diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index ab974ff..228d2b5 100644
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -82,6 +82,15 @@ EXPORtested  T_SYMBOL(acpi_strict);
acpi_interrupt_flags acpi_sci_flags __initdata;
int acpi_sci_override_gsi __initdata;
int acpi_skip_timer_override __initdata;
+int acpi_hpet_lrr;	/* the HPET Legacy routing replacement option
passed through ACPI Table */
+int hpet_lrr_force;	/* cmdlinetested  opt. for faulty bioses not
setting ACPI HPET entry right */
+
+static int hpet_lrr_setup (char *str)
+{
+	get_option(&str,&hpet_lrr_force);
+	return 1;
+}
+__setup ("hpet_lrr=", hpet_lrr_setup);

#ifdef CONFIG_X86_LOCAL_APIC
static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
@@ -669,6 +678,10 @@ #define HPET_RESOURCE_NAME_SIZE 9
			 "HPET %u", hpet_tbl->number);
		hpet_res->end = (1 * 1024) - 1;
	}
+	acpi_hpet_lrr = (hpet_tbl->id & ACPI_HPET_LRR_CAP) ? 1 : 0;
+	/* Print a message to warn about the bios BUG if HPET ACPI is not
correctly populated */
+	printk(KERN_INFO PREFIX "HPET id: %#x. ACPI LRR bit %s SET\n",
+			hpet_tbl->id, acpi_hpet_lrr ? "": "NOT");

#ifdef	CONFIG_X86_64
	vxtime.hpet_address = hpet_tbl->addr.addrl |
diff --git a/arch/i386/kernel/time_hpet.c b/arch/i386/kernel/time_hpet.c
index 1a2a979..01b2f67 100644
--- a/arch/i386/kernel/time_hpet.c
+++ b/arch/i386/kernel/time_hpet.c
@@ -94,7 +94,8 @@ static int hpet_timer_stop_set_go(unsign
 	 * Go!
 	 */
	cfg = hpet_readl(HPET_CFG);
-	if (hpet_use_timer)
+	/* Ideally the following should be &&(acpi_hpet_lrr || hpet_lrr_force) */
+	if (hpet_use_timer && hpet_lrr_force)
		cfg |= HPET_CFG_LEGACY;
	cfg |= HPET_CFG_ENABLE;
	hpet_writel(cfg, HPET_CFG);
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 1ba5a44..3417c0f 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -48,6 +48,8 @@ static void cpufreq_delayed_get(void);
#endif
extern void i8254_timer_resume(void);
extern int using_apic_timer;
+extern int acpi_hpet_lrr;
+extern int hpet_lrr_force;

static char *timename = NULL;

@@ -783,7 +785,10 @@ static int hpet_timer_stop_set_go(unsign
		    HPET_TN_32BIT, HPET_T0_CFG);
		hpet_writel(hpet_tick, HPET_T0_CMP); /* next interrupt */
		hpet_writel(hpet_tick, HPET_T0_CMP); /* period */
-		cfg |= HPET_CFG_LEGACY;
+		/* Ideally the following should be (acpi_hpet_lrr || hpet_lrr_force) */
+		if (hpet_lrr_force)
+			cfg |= HPET_CFG_LEGACY;
+
	}
/*
 * Go!
@@ -887,6 +892,7 @@ time_cpu_notifier(struct notifier_block

void __init time_init(void)
{
+	int timer_irq = 0;
	if (nohpet)
		vxtime.hpet_address = 0;

@@ -906,6 +912,10 @@ void __init time_init(void)
	  	tick_nsec = TICK_NSEC_HPET;
		cpu_khz = hpet_calibrate_tsc();
		timename = "HPET";
+		/* Ideally the following should be (acpi_hpet_lrr || hpet_lrr_force) */
+		if (hpet_lrr_force)
+			timer_irq = HPET_TIMER_LRR_IRQ;
+
#ifdef CONFIG_X86_PM_TIMER
	} else if (pmtmr_ioport && !vxtime.hpet_address) {
		vxtime_hz = PM_TIMER_FREQUENCY;
@@ -924,7 +934,8 @@ #endif
	vxtime.tsc_quot = (USEC_PER_MSEC << US_SCALE) / cpu_khz;
	vxtime.last_tsc = get_cycles_sync();
	set_cyc2ns_scale(cpu_khz);
-	setup_irq(0, &irq0);
+	printk (KERN_WARNING PREFIX "Registering Timer IRQ = %d\n", timer_irq);
+	setup_irq(timer_irq, &irq0);
	hotcpu_notifier(time_cpu_notifier, 0);
	time_cpu_notifier(NULL, CPU_ONLINE, (void *)(long)smp_processor_id());

diff --git a/include/asm-x86_64/hpet.h b/include/asm-x86_64/hpet.h
index b390984..2d18b39 100644
--- a/include/asm-x86_64/hpet.h
+++ b/include/asm-x86_64/hpet.h
@@ -37,6 +37,7 @@ #define HPET_CFG_ENABLE	0x001
#define HPET_CFG_LEGACY	0x002
#define	HPET_LEGACY_8254	2
#define	HPET_LEGACY_RTC		8
+#define	HPET_TIMER_LRR_IRQ	2

#define HPET_TN_LEVEL		0x0002
#define HPET_TN_ENABLE		0x0004
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 2b0c955..62dab08 100644
--- a/include/linux/acpi.h arch/i386/kernel/acpi/boot.c |   13 +++++++++++++
arch/i386/kernel/time_hpet.c |    3 ++-
arch/x86_64/kernel/time.c    |   15 +++++++++++++--
include/asm-x86_64/hpet.h    |    1 +
include/linux/acpi.h         |    1 +
5 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index ab974ff..228d2b5 100644
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -82,6 +82,15 @@ EXPORtested  T_SYMBOL(acpi_strict);
acpi_interrupt_flags acpi_sci_flags __initdata;
int acpi_sci_override_gsi __initdata;
int acpi_skip_timer_override __initdata;
+int acpi_hpet_lrr;	/* the HPET Legacy routing replacement option
passed through ACPI Table */
+int hpet_lrr_force;	/* cmdlinetested  opt. for faulty bioses not
setting ACPI HPET entry right */
+
+static int hpet_lrr_setup (char *str)
+{
+	get_option(&str,&hpet_lrr_force);
+	return 1;
+}
+__setup ("hpet_lrr=", hpet_lrr_setup);

#ifdef CONFIG_X86_LOCAL_APIC
static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE;
@@ -669,6 +678,10 @@ #define HPET_RESOURCE_NAME_SIZE 9
			 "HPET %u", hpet_tbl->number);
		hpet_res->end = (1 * 1024) - 1;
	}
+	acpi_hpet_lrr = (hpet_tbl->id & ACPI_HPET_LRR_CAP) ? 1 : 0;
+	/* Print a message to warn about the bios BUG if HPET ACPI is not
correctly populated */
+	printk(KERN_INFO PREFIX "HPET id: %#x. ACPI LRR bit %s SET\n",
+			hpet_tbl->id, acpi_hpet_lrr ? "": "NOT");

#ifdef	CONFIG_X86_64
	vxtime.hpet_address = hpet_tbl->addr.addrl |
diff --git a/arch/i386/kernel/time_hpet.c b/arch/i386/kernel/time_hpet.c
index 1a2a979..01b2f67 100644
--- a/arch/i386/kernel/time_hpet.c
+++ b/arch/i386/kernel/time_hpet.c
@@ -94,7 +94,8 @@ static int hpet_timer_stop_set_go(unsign
 	 * Go!
 	 */
	cfg = hpet_readl(HPET_CFG);
-	if (hpet_use_timer)
+	/* Ideally the following should be &&(acpi_hpet_lrr || hpet_lrr_force) */
+	if (hpet_use_timer && hpet_lrr_force)
		cfg |= HPET_CFG_LEGACY;
	cfg |= HPET_CFG_ENABLE;
	hpet_writel(cfg, HPET_CFG);
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 1ba5a44..3417c0f 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -48,6 +48,8 @@ static void cpufreq_delayed_get(void);
#endif
extern void i8254_timer_resume(void);
extern int using_apic_timer;
+extern int acpi_hpet_lrr;
+extern int hpet_lrr_force;

static char *timename = NULL;

@@ -783,7 +785,10 @@ static int hpet_timer_stop_set_go(unsign
		    HPET_TN_32BIT, HPET_T0_CFG);
		hpet_writel(hpet_tick, HPET_T0_CMP); /* next interrupt */
		hpet_writel(hpet_tick, HPET_T0_CMP); /* period */
-		cfg |= HPET_CFG_LEGACY;
+		/* Ideally the following should be (acpi_hpet_lrr || hpet_lrr_force) */
+		if (hpet_lrr_force)
+			cfg |= HPET_CFG_LEGACY;
+
	}
/*
 * Go!
@@ -887,6 +892,7 @@ time_cpu_notifier(struct notifier_block

void __init time_init(void)
{
+	int timer_irq = 0;
	if (nohpet)
		vxtime.hpet_address = 0;

@@ -906,6 +912,10 @@ void __init time_init(void)
	  	tick_nsec = TICK_NSEC_HPET;
		cpu_khz = hpet_calibrate_tsc();
		timename = "HPET";
+		/* Ideally the following should be (acpi_hpet_lrr || hpet_lrr_force) */
+		if (hpet_lrr_force)
+			timer_irq = HPET_TIMER_LRR_IRQ;
+
#ifdef CONFIG_X86_PM_TIMER
	} else if (pmtmr_ioport && !vxtime.hpet_address) {
		vxtime_hz = PM_TIMER_FREQUENCY;
@@ -924,7 +934,8 @@ #endif
	vxtime.tsc_quot = (USEC_PER_MSEC << US_SCALE) / cpu_khz;
	vxtime.last_tsc = get_cycles_sync();
	set_cyc2ns_scale(cpu_khz);
-	setup_irq(0, &irq0);
+	printk (KERN_WARNING PREFIX "Registering Timer IRQ = %d\n", timer_irq);
+	setup_irq(timer_irq, &irq0);
	hotcpu_notifier(time_cpu_notifier, 0);
	time_cpu_notifier(NULL, CPU_ONLINE, (void *)(long)smp_processor_id());

diff --git a/include/asm-x86_64/hpet.h b/include/asm-x86_64/hpet.h
index b390984..2d18b39 100644
--- a/include/asm-x86_64/hpet.h
+++ b/include/asm-x86_64/hpet.h
@@ -37,6 +37,7 @@ #define HPET_CFG_ENABLE	0x001
#define HPET_CFG_LEGACY	0x002
#define	HPET_LEGACY_8254	2
#define	HPET_LEGACY_RTC		8
+#define	HPET_TIMER_LRR_IRQ	2

#define HPET_TN_LEVEL		0x0002
#define HPET_TN_ENABLE		0x0004
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index 2b0c955..62dab08 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -220,6 +220,7 @@ enum acpi_interrupt_id {
};

#define	ACPI_SPACE_MEM		0
+#define	ACPI_HPET_LRR_CAP	0x8000

struct acpi_gen_regaddr {
	u8  space_id;
+++ b/include/linux/acpi.h
@@ -220,6 +220,7 @@ enum acpi_interrupt_id {
};

#define	ACPI_SPACE_MEM		0
+#define	ACPI_HPET_LRR_CAP	0x8000

struct acpi_gen_regaddr {
	u8  space_id;
-
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