From b98103a5597b87211a1c74077b06faeac554bedc Mon Sep 17 00:00:00 2001 From: Andreas Herrmann Date: Sat, 21 Feb 2009 00:09:47 +0100 Subject: [PATCH 1/3] x86: hpet: print HPET registers during setup (if hpet=verbose is used) Signed-off-by: Andreas Herrmann Cc: Mark Hounschell Cc: Borislav Petkov Signed-off-by: Ingo Molnar --- Documentation/kernel-parameters.txt | 4 ++- arch/x86/kernel/hpet.c | 45 +++++++++++++++++++++++++++++ 2 files changed, 48 insertions(+), 1 deletion(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index b182626739ea..01379a822646 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -492,10 +492,12 @@ and is between 256 and 4096 characters. It is defined in the file Default: 64 hpet= [X86-32,HPET] option to control HPET usage - Format: { enable (default) | disable | force } + Format: { enable (default) | disable | force | + verbose } disable: disable HPET and use PIT instead force: allow force enabled of undocumented chips (ICH4, VIA, nVidia) + verbose: show contents of HPET registers during setup com20020= [HW,NET] ARCnet - COM20020 chipset Format: diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index a00545fe5cdd..1d86ca3c1f97 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -80,6 +80,7 @@ static inline void hpet_clear_mapping(void) */ static int boot_hpet_disable; int hpet_force_user; +static int hpet_verbose; static int __init hpet_setup(char *str) { @@ -88,6 +89,8 @@ static int __init hpet_setup(char *str) boot_hpet_disable = 1; if (!strncmp("force", str, 5)) hpet_force_user = 1; + if (!strncmp("verbose", str, 7)) + hpet_verbose = 1; } return 1; } @@ -119,6 +122,43 @@ int is_hpet_enabled(void) } EXPORT_SYMBOL_GPL(is_hpet_enabled); +static void _hpet_print_config(const char *function, int line) +{ + u32 i, timers, l, h; + printk(KERN_INFO "hpet: %s(%d):\n", function, line); + l = hpet_readl(HPET_ID); + h = hpet_readl(HPET_PERIOD); + timers = ((l & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1; + printk(KERN_INFO "hpet: ID: 0x%x, PERIOD: 0x%x\n", l, h); + l = hpet_readl(HPET_CFG); + h = hpet_readl(HPET_STATUS); + printk(KERN_INFO "hpet: CFG: 0x%x, STATUS: 0x%x\n", l, h); + l = hpet_readl(HPET_COUNTER); + h = hpet_readl(HPET_COUNTER+4); + printk(KERN_INFO "hpet: COUNTER_l: 0x%x, COUNTER_h: 0x%x\n", l, h); + + for (i = 0; i < timers; i++) { + l = hpet_readl(HPET_Tn_CFG(i)); + h = hpet_readl(HPET_Tn_CFG(i)+4); + printk(KERN_INFO "hpet: T%d: CFG_l: 0x%x, CFG_h: 0x%x\n", + i, l, h); + l = hpet_readl(HPET_Tn_CMP(i)); + h = hpet_readl(HPET_Tn_CMP(i)+4); + printk(KERN_INFO "hpet: T%d: CMP_l: 0x%x, CMP_h: 0x%x\n", + i, l, h); + l = hpet_readl(HPET_Tn_ROUTE(i)); + h = hpet_readl(HPET_Tn_ROUTE(i)+4); + printk(KERN_INFO "hpet: T%d ROUTE_l: 0x%x, ROUTE_h: 0x%x\n", + i, l, h); + } +} + +#define hpet_print_config() \ +do { \ + if (hpet_verbose) \ + _hpet_print_config(__FUNCTION__, __LINE__); \ +} while (0) + /* * When the hpet driver (/dev/hpet) is enabled, we need to reserve * timer 0 and timer 1 in case of RTC emulation. @@ -282,6 +322,7 @@ static void hpet_set_mode(enum clock_event_mode mode, hpet_writel(cmp, HPET_Tn_CMP(timer)); udelay(1); hpet_writel((unsigned long) delta, HPET_Tn_CMP(timer)); + hpet_print_config(); break; case CLOCK_EVT_MODE_ONESHOT: @@ -308,6 +349,7 @@ static void hpet_set_mode(enum clock_event_mode mode, irq_set_affinity(hdev->irq, cpumask_of(hdev->cpu)); enable_irq(hdev->irq); } + hpet_print_config(); break; } } @@ -526,6 +568,7 @@ static void hpet_msi_capability_lookup(unsigned int start_timer) num_timers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT); num_timers++; /* Value read out starts from 0 */ + hpet_print_config(); hpet_devs = kzalloc(sizeof(struct hpet_dev) * num_timers, GFP_KERNEL); if (!hpet_devs) @@ -793,6 +836,7 @@ int __init hpet_enable(void) * information and the number of channels */ id = hpet_readl(HPET_ID); + hpet_print_config(); #ifdef CONFIG_HPET_EMULATE_RTC /* @@ -845,6 +889,7 @@ static __init int hpet_late_init(void) return -ENODEV; hpet_reserve_platform_timers(hpet_readl(HPET_ID)); + hpet_print_config(); for_each_online_cpu(cpu) { hpet_cpuhp_notify(NULL, CPU_ONLINE, (void *)(long)cpu); From 8d6f0c8214928f7c5083dd54ecb69c5d615b516e Mon Sep 17 00:00:00 2001 From: Andreas Herrmann Date: Sat, 21 Feb 2009 00:10:44 +0100 Subject: [PATCH 2/3] x86: hpet: provide separate functions to stop and start the counter By splitting up existing hpet_start_counter function. Signed-off-by: Andreas Herrmann Cc: Mark Hounschell Cc: Borislav Petkov Signed-off-by: Ingo Molnar --- arch/x86/kernel/hpet.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index 1d86ca3c1f97..7ae1f1e8b9b7 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -231,27 +231,37 @@ static struct clock_event_device hpet_clockevent = { .rating = 50, }; -static void hpet_start_counter(void) +static void hpet_stop_counter(void) { unsigned long 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); +} + +static void hpet_start_counter(void) +{ + unsigned long cfg = hpet_readl(HPET_CFG); cfg |= HPET_CFG_ENABLE; hpet_writel(cfg, HPET_CFG); } +static void hpet_restart_counter(void) +{ + hpet_stop_counter(); + hpet_start_counter(); +} + static void hpet_resume_device(void) { force_hpet_resume(); } -static void hpet_restart_counter(void) +static void hpet_resume_counter(void) { hpet_resume_device(); - hpet_start_counter(); + hpet_restart_counter(); } static void hpet_enable_legacy_int(void) @@ -738,7 +748,7 @@ static struct clocksource clocksource_hpet = { .mask = HPET_MASK, .shift = HPET_SHIFT, .flags = CLOCK_SOURCE_IS_CONTINUOUS, - .resume = hpet_restart_counter, + .resume = hpet_resume_counter, #ifdef CONFIG_X86_64 .vread = vread_hpet, #endif @@ -750,7 +760,7 @@ static int hpet_clocksource_register(void) cycle_t t1; /* Start the counter */ - hpet_start_counter(); + hpet_restart_counter(); /* Verify whether hpet counter works */ t1 = read_hpet(); From c23e253e67c9d8a91a0ffa33c1f571a17f0a2403 Mon Sep 17 00:00:00 2001 From: Andreas Herrmann Date: Sat, 21 Feb 2009 00:16:35 +0100 Subject: [PATCH 3/3] x86: hpet: stop HPET_COUNTER when programming periodic mode Impact: fix system hang on some systems operating with HZ_1000 On a system that stalled with HZ_1000, the first value written to T0_CMP (when the main counter was not stopped) did not trigger an interrupt. Instead after the main counter wrapped around (after several minutes) an interrupt was triggered and afterwards the periodic interrupt took effect. This can be fixed by implementing HPET spec recommendation for programming the periodic mode (i.e. stopping the main counter). Signed-off-by: Andreas Herrmann Cc: Mark Hounschell Cc: Borislav Petkov Signed-off-by: Ingo Molnar --- arch/x86/kernel/hpet.c | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c index 7ae1f1e8b9b7..648b3a2a3a44 100644 --- a/arch/x86/kernel/hpet.c +++ b/arch/x86/kernel/hpet.c @@ -309,29 +309,22 @@ static int hpet_setup_msi_irq(unsigned int irq); static void hpet_set_mode(enum clock_event_mode mode, struct clock_event_device *evt, int timer) { - unsigned long cfg, cmp, now; + unsigned long cfg; uint64_t delta; switch (mode) { case CLOCK_EVT_MODE_PERIODIC: + hpet_stop_counter(); delta = ((uint64_t)(NSEC_PER_SEC/HZ)) * evt->mult; delta >>= evt->shift; - now = hpet_readl(HPET_COUNTER); - cmp = now + (unsigned long) delta; cfg = hpet_readl(HPET_Tn_CFG(timer)); /* Make sure we use edge triggered interrupts */ cfg &= ~HPET_TN_LEVEL; cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_SETVAL | HPET_TN_32BIT; hpet_writel(cfg, HPET_Tn_CFG(timer)); - /* - * The first write after writing TN_SETVAL to the - * config register sets the counter value, the second - * write sets the period. - */ - hpet_writel(cmp, HPET_Tn_CMP(timer)); - udelay(1); hpet_writel((unsigned long) delta, HPET_Tn_CMP(timer)); + hpet_start_counter(); hpet_print_config(); break;