[PATCH] HPET reenabling after suspend-resume

[PATCH] HPET reenabling after suspend-resume

[Venkatesh Pallipadi]

hpet hardware seems to need a little prodding during resume for it to start 
sending the timer interupts again. Attached patch does it for both i386 
and x86_64.

Makefile change below: Right now suspend-resume ordering of system devices
depends on their order of linking. It is ugly. But, thats the way it works
currently. And we want timer device to resume before PIC.

Signed-off-by:: "Venkatesh Pallipadi" <venkatesh.pallipadi@intel.com>

--- linux-2.6.9//arch/i386/kernel/time.c.org	2004-10-20 17:25:34.000000000 -0700
+++ linux-2.6.9//arch/i386/kernel/time.c	2004-10-22 19:17:03.000000000 -0700
@@ -321,7 +321,7 @@ unsigned long get_cmos_time(void)
 
 static long clock_cmos_diff;
 
-static int time_suspend(struct sys_device *dev, u32 state)
+static int timer_suspend(struct sys_device *dev, u32 state)
 {
 	/*
 	 * Estimate time zone so that set_time can update the clock
@@ -331,10 +331,18 @@ static int time_suspend(struct sys_devic
 	return 0;
 }
 
-static int time_resume(struct sys_device *dev)
+static int timer_resume(struct sys_device *dev)
 {
 	unsigned long flags;
-	unsigned long sec = get_cmos_time() + clock_cmos_diff;
+	unsigned long sec;
+
+#ifdef CONFIG_HPET_TIMER
+	if (is_hpet_enabled()) {
+		hpet_reenable();
+	}
+#endif
+
+	sec = get_cmos_time() + clock_cmos_diff;
 	write_seqlock_irqsave(&xtime_lock, flags);
 	xtime.tv_sec = sec;
 	xtime.tv_nsec = 0;
@@ -342,24 +350,24 @@ static int time_resume(struct sys_device
 	return 0;
 }
 
-static struct sysdev_class pit_sysclass = {
-	.resume = time_resume,
-	.suspend = time_suspend,
-	set_kset_name("pit"),
+static struct sysdev_class timer_sysclass = {
+	.resume = timer_resume,
+	.suspend = timer_suspend,
+	set_kset_name("timer"),
 };
 
 
 /* XXX this driverfs stuff should probably go elsewhere later -john */
-static struct sys_device device_i8253 = {
+static struct sys_device device_timer = {
 	.id	= 0,
-	.cls	= &pit_sysclass,
+	.cls	= &timer_sysclass,
 };
 
 static int time_init_device(void)
 {
-	int error = sysdev_class_register(&pit_sysclass);
+	int error = sysdev_class_register(&timer_sysclass);
 	if (!error)
-		error = sysdev_register(&device_i8253);
+		error = sysdev_register(&device_timer);
 	return error;
 }
 
--- linux-2.6.9//arch/i386/kernel/time_hpet.c.org	2004-10-20 18:08:52.000000000 -0700
+++ linux-2.6.9//arch/i386/kernel/time_hpet.c	2004-10-22 19:18:21.000000000 -0700
@@ -60,13 +60,46 @@ void __init wait_hpet_tick(void)
 }
 #endif
 
+static int hpet_timer_stop_set_go(unsigned long tick)
+{
+	unsigned int cfg;
+
+	/*
+	 * Stop the timers and reset the main counter.
+	 */
+	cfg = hpet_readl(HPET_CFG);
+	cfg &= ~HPET_CFG_ENABLE;
+	hpet_writel(cfg, HPET_CFG);
+	hpet_writel(0, HPET_COUNTER);
+	hpet_writel(0, HPET_COUNTER + 4);
+
+	/*
+	 * Set up timer 0, as periodic with first interrupt to happen at
+	 * hpet_tick, and period also hpet_tick.
+	 */
+	cfg = hpet_readl(HPET_T0_CFG);
+	cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC |
+	       HPET_TN_SETVAL | HPET_TN_32BIT;
+	hpet_writel(cfg, HPET_T0_CFG);
+	hpet_writel(tick, HPET_T0_CMP);
+
+	/*
+ 	 * Go!
+ 	 */
+	cfg = hpet_readl(HPET_CFG);
+	cfg |= HPET_CFG_ENABLE | HPET_CFG_LEGACY;
+	hpet_writel(cfg, HPET_CFG);
+
+	return 0;
+}
+
 /*
  * Check whether HPET was found by ACPI boot parse. If yes setup HPET
  * counter 0 for kernel base timer.
  */
 int __init hpet_enable(void)
 {
-	unsigned int cfg, id;
+	unsigned int id;
 	unsigned long tick_fsec_low, tick_fsec_high; /* tick in femto sec */
 	unsigned long hpet_tick_rem;
 
@@ -108,31 +141,8 @@ int __init hpet_enable(void)
 	if (hpet_tick_rem > (hpet_period >> 1))
 		hpet_tick++; /* rounding the result */
 
-	/*
-	 * Stop the timers and reset the main counter.
-	 */
-	cfg = hpet_readl(HPET_CFG);
-	cfg &= ~HPET_CFG_ENABLE;
-	hpet_writel(cfg, HPET_CFG);
-	hpet_writel(0, HPET_COUNTER);
-	hpet_writel(0, HPET_COUNTER + 4);
-
-	/*
-	 * Set up timer 0, as periodic with first interrupt to happen at
-	 * hpet_tick, and period also hpet_tick.
-	 */
-	cfg = hpet_readl(HPET_T0_CFG);
-	cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC |
-	       HPET_TN_SETVAL | HPET_TN_32BIT;
-	hpet_writel(cfg, HPET_T0_CFG);
-	hpet_writel(hpet_tick, HPET_T0_CMP);
-
-	/*
- 	 * Go!
- 	 */
-	cfg = hpet_readl(HPET_CFG);
-	cfg |= HPET_CFG_ENABLE | HPET_CFG_LEGACY;
-	hpet_writel(cfg, HPET_CFG);
+	if (hpet_timer_stop_set_go(hpet_tick))
+		return -1;
 
 	use_hpet = 1;
 
@@ -185,6 +195,11 @@ int __init hpet_enable(void)
 	return 0;
 }
 
+int hpet_reenable(void)
+{
+	return hpet_timer_stop_set_go(hpet_tick);
+}
+
 int is_hpet_enabled(void)
 {
 	return use_hpet;
--- linux-2.6.9//include/asm-i386/hpet.h.org	2004-10-21 11:48:19.000000000 -0700
+++ linux-2.6.9//include/asm-i386/hpet.h	2004-10-22 19:17:03.000000000 -0700
@@ -96,6 +96,7 @@ extern unsigned long hpet_address;	/* hp
 
 extern int hpet_rtc_timer_init(void);
 extern int hpet_enable(void);
+extern int hpet_reenable(void);
 extern int is_hpet_enabled(void);
 extern int is_hpet_capable(void);
 extern int hpet_readl(unsigned long a);
--- linux-2.6.9//arch/i386/kernel/Makefile.org	2004-10-21 11:39:46.000000000 -0700
+++ linux-2.6.9//arch/i386/kernel/Makefile	2004-10-22 19:17:03.000000000 -0700
@@ -5,7 +5,7 @@
 extra-y := head.o init_task.o vmlinux.lds
 
 obj-y	:= process.o semaphore.o signal.o entry.o traps.o irq.o vm86.o \
-		ptrace.o i8259.o ioport.o ldt.o setup.o time.o sys_i386.o \
+		ptrace.o time.o ioport.o ldt.o setup.o i8259.o sys_i386.o \
 		pci-dma.o i386_ksyms.o i387.o dmi_scan.o bootflag.o \
 		doublefault.o
 
--- linux-2.6.9//arch/x86_64/kernel/time.c.org	2004-10-21 11:55:31.000000000 -0700
+++ linux-2.6.9//arch/x86_64/kernel/time.c	2004-10-22 19:18:41.000000000 -0700
@@ -723,31 +723,9 @@ static unsigned int __init pit_calibrate
 	return (end - start) / 50;
 }
 
-static int hpet_init(void)
+static int hpet_timer_stop_set_go(unsigned long tick)
 {
-	unsigned int cfg, id;
-
-	if (!vxtime.hpet_address)
-		return -1;
-	set_fixmap_nocache(FIX_HPET_BASE, vxtime.hpet_address);
-	__set_fixmap(VSYSCALL_HPET, vxtime.hpet_address, PAGE_KERNEL_VSYSCALL_NOCACHE);
-
-/*
- * Read the period, compute tick and quotient.
- */
-
-	id = hpet_readl(HPET_ID);
-
-	if (!(id & HPET_ID_VENDOR) || !(id & HPET_ID_NUMBER) ||
-	    !(id & HPET_ID_LEGSUP))
-		return -1;
-
-	hpet_period = hpet_readl(HPET_PERIOD);
-	if (hpet_period < 100000 || hpet_period > 100000000)
-		return -1;
-
-	hpet_tick = (1000000000L * (USEC_PER_SEC / HZ) + hpet_period / 2) /
-		hpet_period;
+	unsigned int cfg;
 
 /*
  * Stop the timers and reset the main counter.
@@ -779,6 +757,40 @@ static int hpet_init(void)
 	return 0;
 }
 
+static int hpet_init(void)
+{
+	unsigned int id;
+
+	if (!vxtime.hpet_address)
+		return -1;
+	set_fixmap_nocache(FIX_HPET_BASE, vxtime.hpet_address);
+	__set_fixmap(VSYSCALL_HPET, vxtime.hpet_address, PAGE_KERNEL_VSYSCALL_NOCACHE);
+
+/*
+ * Read the period, compute tick and quotient.
+ */
+
+	id = hpet_readl(HPET_ID);
+
+	if (!(id & HPET_ID_VENDOR) || !(id & HPET_ID_NUMBER) ||
+	    !(id & HPET_ID_LEGSUP))
+		return -1;
+
+	hpet_period = hpet_readl(HPET_PERIOD);
+	if (hpet_period < 100000 || hpet_period > 100000000)
+		return -1;
+
+	hpet_tick = (1000000000L * (USEC_PER_SEC / HZ) + hpet_period / 2) /
+		hpet_period;
+
+	return hpet_timer_stop_set_go(hpet_tick);
+}
+
+static int hpet_reenable(void)
+{
+	return hpet_timer_stop_set_go(hpet_tick);
+}
+
 void __init pit_init(void)
 {
 	unsigned long flags;
@@ -872,7 +884,7 @@ __setup("report_lost_ticks", time_setup)
 
 static long clock_cmos_diff;
 
-static int time_suspend(struct sys_device *dev, u32 state)
+static int timer_suspend(struct sys_device *dev, u32 state)
 {
 	/*
 	 * Estimate time zone so that set_time can update the clock
@@ -882,10 +894,15 @@ static int time_suspend(struct sys_devic
 	return 0;
 }
 
-static int time_resume(struct sys_device *dev)
+static int timer_resume(struct sys_device *dev)
 {
 	unsigned long flags;
-	unsigned long sec = get_cmos_time() + clock_cmos_diff;
+	unsigned long sec;
+
+	if (is_hpet_enabled())
+		hpet_reenable();
+
+	sec = get_cmos_time() + clock_cmos_diff;
 	write_seqlock_irqsave(&xtime_lock,flags);
 	xtime.tv_sec = sec;
 	xtime.tv_nsec = 0;
@@ -893,24 +910,24 @@ static int time_resume(struct sys_device
 	return 0;
 }
 
-static struct sysdev_class pit_sysclass = {
-	.resume = time_resume,
-	.suspend = time_suspend,
-	set_kset_name("pit"),
+static struct sysdev_class timer_sysclass = {
+	.resume = timer_resume,
+	.suspend = timer_suspend,
+	set_kset_name("timer"),
 };
 
 
 /* XXX this driverfs stuff should probably go elsewhere later -john */
-static struct sys_device device_i8253 = {
+static struct sys_device device_timer = {
 	.id	= 0,
-	.cls	= &pit_sysclass,
+	.cls	= &timer_sysclass,
 };
 
 static int time_init_device(void)
 {
-	int error = sysdev_class_register(&pit_sysclass);
+	int error = sysdev_class_register(&timer_sysclass);
 	if (!error)
-		error = sysdev_register(&device_i8253);
+		error = sysdev_register(&device_timer);
 	return error;
 }
 
--- linux-2.6.9//arch/x86_64/kernel/Makefile.org	2004-10-21 11:58:56.000000000 -0700
+++ linux-2.6.9//arch/x86_64/kernel/Makefile	2004-10-22 19:17:03.000000000 -0700
@@ -5,7 +5,7 @@
 extra-y 	:= head.o head64.o init_task.o vmlinux.lds
 EXTRA_AFLAGS	:= -traditional
 obj-y	:= process.o semaphore.o signal.o entry.o traps.o irq.o \
-		ptrace.o i8259.o ioport.o ldt.o setup.o time.o sys_x86_64.o \
+		ptrace.o time.o ioport.o ldt.o setup.o i8259.o sys_x86_64.o \
 		x8664_ksyms.o i387.o syscall.o vsyscall.o \
 		setup64.o bootflag.o e820.o reboot.o warmreboot.o
 obj-y += mce.o

Re: [PATCH] HPET reenabling after suspend-resume

[Andi Kleen]

On Fri, Oct 22, 2004 at 05:26:59PM -0700, Venkatesh Pallipadi wrote:
> 
> hpet hardware seems to need a little prodding during resume for it to start 
> sending the timer interupts again. Attached patch does it for both i386 
> and x86_64.

Hmm, what HPET hardware? It must have worked on some machines already,
otherwise suspend/resume would have never worked on many AMD x86-64 
machines. 


Anyways, looks good.

-Andi

RE: [PATCH] HPET reenabling after suspend-resume

[Pallipadi, Venkatesh]

>-----Original Message-----
>From: Andi Kleen [mailto:ak@suse.de] 
>Sent: Friday, October 22, 2004 6:07 PM
>To: Pallipadi, Venkatesh
>Cc: akpm@osdl.org; linux-kernel@vger.kernel.org; ak@suse.de; 
>pavel@ucw.cz
>Subject: Re: [PATCH] HPET reenabling after suspend-resume
>
>On Fri, Oct 22, 2004 at 05:26:59PM -0700, Venkatesh Pallipadi wrote:
>> 
>> hpet hardware seems to need a little prodding during resume 
>for it to start 
>> sending the timer interupts again. Attached patch does it 
>for both i386 
>> and x86_64.
>
>Hmm, what HPET hardware? It must have worked on some machines already,
>otherwise suspend/resume would have never worked on many AMD x86-64 
>machines. 
>

That's interesting.... 
I ran into this issue where resume was hanging at 8259_resume 
code as the HPET was not counting. That was on an ICH4 based Pentium-M
box.

I will try it on come ICH5 based hardware and see whether it is really 
Required, for both i386 and x86-64, on a wider range of systems.

Thanks,
venki

Re: [PATCH] HPET reenabling after suspend-resume

[Pavel Machek]

Hi!

> >> hpet hardware seems to need a little prodding during resume 
> >for it to start 
> >> sending the timer interupts again. Attached patch does it 
> >for both i386 
> >> and x86_64.
> >
> >Hmm, what HPET hardware? It must have worked on some machines already,
> >otherwise suspend/resume would have never worked on many AMD x86-64 
> >machines. 

Well, swsusp could work by accident and S3 is was not getting too much
testing...

Patch is quite long, but looks ok to me.
								Pavel
-- 
People were complaining that M$ turns users into beta-testers...
...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl!