From 36d8593ec74dc04d3bd7c1c897a7b7cfbd0b0dc6 Mon Sep 17 00:00:00 2001 From: Russell King - ARM Linux Date: Sat, 19 Feb 2011 15:34:50 +0000 Subject: Make clocksource name const As nothing should be writing to the clocksource name string, make the clocksource name pointer const. Build-tested on ARM Versatile Express. Signed-off-by: Russell King Signed-off-by: John Stultz --- include/linux/clocksource.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index c37b21ad5a3b..94c1f38e922a 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -161,7 +161,7 @@ struct clocksource { /* * First part of structure is read mostly */ - char *name; + const char *name; struct list_head list; int rating; cycle_t (*read)(struct clocksource *cs); -- cgit v1.2.3 From b01cc1b0eae0dea19257b29347116505fbedf679 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Mon, 26 Apr 2010 19:03:05 -0700 Subject: x86: Convert remaining x86 clocksources to clocksource_register_hz/khz This converts the remaining x86 clocksources to use clocksource_register_hz/khz. CC: jacob.jun.pan@intel.com CC: Glauber Costa CC: Dimitri Sivanich CC: Rusty Russell CC: Jeremy Fitzhardinge CC: Chris McDermott CC: Thomas Gleixner Tested-by: Konrad Rzeszutek Wilk [xen] Signed-off-by: John Stultz --- arch/x86/kernel/apb_timer.c | 10 +--------- arch/x86/kernel/i8253.c | 6 +----- arch/x86/kernel/kvmclock.c | 6 +----- arch/x86/lguest/boot.c | 4 +--- arch/x86/platform/uv/uv_time.c | 6 +----- arch/x86/xen/time.c | 6 +----- drivers/clocksource/cyclone.c | 10 ++-------- 7 files changed, 8 insertions(+), 40 deletions(-) diff --git a/arch/x86/kernel/apb_timer.c b/arch/x86/kernel/apb_timer.c index 51ef31a89be9..29ebf5a3b192 100644 --- a/arch/x86/kernel/apb_timer.c +++ b/arch/x86/kernel/apb_timer.c @@ -177,7 +177,6 @@ static struct clocksource clocksource_apbt = { .rating = APBT_CLOCKSOURCE_RATING, .read = apbt_read_clocksource, .mask = APBT_MASK, - .shift = APBT_SHIFT, .flags = CLOCK_SOURCE_IS_CONTINUOUS, .resume = apbt_restart_clocksource, }; @@ -595,14 +594,7 @@ static int apbt_clocksource_register(void) if (t1 == apbt_read_clocksource(&clocksource_apbt)) panic("APBT counter not counting. APBT disabled\n"); - /* - * initialize and register APBT clocksource - * convert that to ns/clock cycle - * mult = (ns/c) * 2^APBT_SHIFT - */ - clocksource_apbt.mult = div_sc(MSEC_PER_SEC, - (unsigned long) apbt_freq, APBT_SHIFT); - clocksource_register(&clocksource_apbt); + clocksource_register_khz(&clocksource_apbt, (u32)apbt_freq*1000); return 0; } diff --git a/arch/x86/kernel/i8253.c b/arch/x86/kernel/i8253.c index 2dfd31597443..212fe6590aab 100644 --- a/arch/x86/kernel/i8253.c +++ b/arch/x86/kernel/i8253.c @@ -188,8 +188,6 @@ static struct clocksource pit_cs = { .rating = 110, .read = pit_read, .mask = CLOCKSOURCE_MASK(32), - .mult = 0, - .shift = 20, }; static int __init init_pit_clocksource(void) @@ -205,9 +203,7 @@ static int __init init_pit_clocksource(void) pit_ce.mode != CLOCK_EVT_MODE_PERIODIC) return 0; - pit_cs.mult = clocksource_hz2mult(CLOCK_TICK_RATE, pit_cs.shift); - - return clocksource_register(&pit_cs); + return clocksource_register_hz(&pit_cs, CLOCK_TICK_RATE); } arch_initcall(init_pit_clocksource); diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index f98d3eafe07a..6389a6bca11b 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -26,8 +26,6 @@ #include #include -#define KVM_SCALE 22 - static int kvmclock = 1; static int msr_kvm_system_time = MSR_KVM_SYSTEM_TIME; static int msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK; @@ -120,8 +118,6 @@ static struct clocksource kvm_clock = { .read = kvm_clock_get_cycles, .rating = 400, .mask = CLOCKSOURCE_MASK(64), - .mult = 1 << KVM_SCALE, - .shift = KVM_SCALE, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; @@ -203,7 +199,7 @@ void __init kvmclock_init(void) machine_ops.crash_shutdown = kvm_crash_shutdown; #endif kvm_get_preset_lpj(); - clocksource_register(&kvm_clock); + clocksource_register_hz(&kvm_clock, NSEC_PER_SEC); pv_info.paravirt_enabled = 1; pv_info.name = "KVM"; diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c index eba687f0cc0c..5b96fd95bdab 100644 --- a/arch/x86/lguest/boot.c +++ b/arch/x86/lguest/boot.c @@ -913,8 +913,6 @@ static struct clocksource lguest_clock = { .rating = 200, .read = lguest_clock_read, .mask = CLOCKSOURCE_MASK(64), - .mult = 1 << 22, - .shift = 22, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; @@ -997,7 +995,7 @@ static void lguest_time_init(void) /* Set up the timer interrupt (0) to go to our simple timer routine */ set_irq_handler(0, lguest_time_irq); - clocksource_register(&lguest_clock); + clocksource_register_hz(&lguest_clock, NSEC_PER_SEC); /* We can't set cpumask in the initializer: damn C limitations! Set it * here and register our timer device. */ diff --git a/arch/x86/platform/uv/uv_time.c b/arch/x86/platform/uv/uv_time.c index 9daf5d1af9f1..0eb90184515f 100644 --- a/arch/x86/platform/uv/uv_time.c +++ b/arch/x86/platform/uv/uv_time.c @@ -40,7 +40,6 @@ static struct clocksource clocksource_uv = { .rating = 400, .read = uv_read_rtc, .mask = (cycle_t)UVH_RTC_REAL_TIME_CLOCK_MASK, - .shift = 10, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; @@ -372,14 +371,11 @@ static __init int uv_rtc_setup_clock(void) if (!is_uv_system()) return -ENODEV; - clocksource_uv.mult = clocksource_hz2mult(sn_rtc_cycles_per_second, - clocksource_uv.shift); - /* If single blade, prefer tsc */ if (uv_num_possible_blades() == 1) clocksource_uv.rating = 250; - rc = clocksource_register(&clocksource_uv); + rc = clocksource_register_hz(&clocksource_uv, sn_rtc_cycles_per_second); if (rc) printk(KERN_INFO "UV RTC clocksource failed rc %d\n", rc); else diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c index 067759e3d6a5..04e11597a8c5 100644 --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -26,8 +26,6 @@ #include "xen-ops.h" -#define XEN_SHIFT 22 - /* Xen may fire a timer up to this many ns early */ #define TIMER_SLOP 100000 #define NS_PER_TICK (1000000000LL / HZ) @@ -211,8 +209,6 @@ static struct clocksource xen_clocksource __read_mostly = { .rating = 400, .read = xen_clocksource_get_cycles, .mask = ~0, - .mult = 1< Date: Mon, 26 Apr 2010 20:20:47 -0700 Subject: ia64: convert to clocksource_register_hz/khz This converts the ia64 clocksources to use clocksource_register_hz/khz CC: Tony Luck CC: Thomas Gleixner Tested-by: Tony Luck [clocksource_itc path] Signed-off-by: John Stultz --- arch/ia64/kernel/cyclone.c | 6 +----- arch/ia64/kernel/time.c | 9 ++------- arch/ia64/sn/kernel/sn2/timer.c | 6 +----- drivers/char/hpet.c | 6 +----- 4 files changed, 5 insertions(+), 22 deletions(-) diff --git a/arch/ia64/kernel/cyclone.c b/arch/ia64/kernel/cyclone.c index d52f1f78eff2..f64097b5118a 100644 --- a/arch/ia64/kernel/cyclone.c +++ b/arch/ia64/kernel/cyclone.c @@ -31,8 +31,6 @@ static struct clocksource clocksource_cyclone = { .rating = 300, .read = read_cyclone, .mask = (1LL << 40) - 1, - .mult = 0, /*to be caluclated*/ - .shift = 16, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; @@ -118,9 +116,7 @@ int __init init_cyclone_clock(void) /* initialize last tick */ cyclone_mc = cyclone_timer; clocksource_cyclone.fsys_mmio = cyclone_timer; - clocksource_cyclone.mult = clocksource_hz2mult(CYCLONE_TIMER_FREQ, - clocksource_cyclone.shift); - clocksource_register(&clocksource_cyclone); + clocksource_register_hz(&clocksource_cyclone, CYCLONE_TIMER_FREQ); return 0; } diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c index 9702fa92489e..41c40f0e4796 100644 --- a/arch/ia64/kernel/time.c +++ b/arch/ia64/kernel/time.c @@ -73,8 +73,6 @@ static struct clocksource clocksource_itc = { .rating = 350, .read = itc_get_cycles, .mask = CLOCKSOURCE_MASK(64), - .mult = 0, /*to be calculated*/ - .shift = 16, .flags = CLOCK_SOURCE_IS_CONTINUOUS, #ifdef CONFIG_PARAVIRT .resume = paravirt_clocksource_resume, @@ -374,11 +372,8 @@ ia64_init_itm (void) ia64_cpu_local_tick(); if (!itc_clocksource) { - /* Sort out mult/shift values: */ - clocksource_itc.mult = - clocksource_hz2mult(local_cpu_data->itc_freq, - clocksource_itc.shift); - clocksource_register(&clocksource_itc); + clocksource_register_hz(&clocksource_itc, + local_cpu_data->itc_freq); itc_clocksource = &clocksource_itc; } } diff --git a/arch/ia64/sn/kernel/sn2/timer.c b/arch/ia64/sn/kernel/sn2/timer.c index 21d6f09e3447..c34efda122e1 100644 --- a/arch/ia64/sn/kernel/sn2/timer.c +++ b/arch/ia64/sn/kernel/sn2/timer.c @@ -33,8 +33,6 @@ static struct clocksource clocksource_sn2 = { .rating = 450, .read = read_sn2, .mask = (1LL << 55) - 1, - .mult = 0, - .shift = 10, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; @@ -57,9 +55,7 @@ ia64_sn_udelay (unsigned long usecs) void __init sn_timer_init(void) { clocksource_sn2.fsys_mmio = RTC_COUNTER_ADDR; - clocksource_sn2.mult = clocksource_hz2mult(sn_rtc_cycles_per_second, - clocksource_sn2.shift); - clocksource_register(&clocksource_sn2); + clocksource_register_hz(&clocksource_sn2, sn_rtc_cycles_per_second); ia64_udelay = &ia64_sn_udelay; } diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c index 7066e801b9d3..051474c65b78 100644 --- a/drivers/char/hpet.c +++ b/drivers/char/hpet.c @@ -84,8 +84,6 @@ static struct clocksource clocksource_hpet = { .rating = 250, .read = read_hpet, .mask = CLOCKSOURCE_MASK(64), - .mult = 0, /* to be calculated */ - .shift = 10, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; static struct clocksource *hpet_clocksource; @@ -934,9 +932,7 @@ int hpet_alloc(struct hpet_data *hdp) if (!hpet_clocksource) { hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc; CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr); - clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq, - clocksource_hpet.shift); - clocksource_register(&clocksource_hpet); + clocksource_register_hz(&clocksource_hpet, hpetp->hp_tick_freq); hpetp->hp_clocksource = &clocksource_hpet; hpet_clocksource = &clocksource_hpet; } -- cgit v1.2.3 From b8f39f7dfe12d4c8402c493a24fbf1e21d086771 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Mon, 26 Apr 2010 20:22:23 -0700 Subject: microblaze: convert to clocksource_register_hz/khz This converts the microblaze clocksources to use clocksource_register_hz/khz CC: Michal Simek CC: Thomas Gleixner Tested-by: Michal Simek Signed-off-by: John Stultz --- arch/microblaze/kernel/timer.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/arch/microblaze/kernel/timer.c b/arch/microblaze/kernel/timer.c index a5aa33db1df3..68ec7d1e8439 100644 --- a/arch/microblaze/kernel/timer.c +++ b/arch/microblaze/kernel/timer.c @@ -217,16 +217,12 @@ static struct clocksource clocksource_microblaze = { .rating = 300, .read = microblaze_read, .mask = CLOCKSOURCE_MASK(32), - .shift = 8, /* I can shift it */ .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; static int __init microblaze_clocksource_init(void) { - clocksource_microblaze.mult = - clocksource_hz2mult(timer_clock_freq, - clocksource_microblaze.shift); - if (clocksource_register(&clocksource_microblaze)) + if (clocksource_register_hz(&clocksource_microblaze, timer_clock_freq)) panic("failed to register clocksource"); /* stop timer1 */ -- cgit v1.2.3 From 7861434fe9b5c9dad1bbb1f674cded95950e778e Mon Sep 17 00:00:00 2001 From: John Stultz Date: Tue, 19 Oct 2010 17:49:07 -0700 Subject: alpha: convert to clocksource_register_hz Converts alpha to use clocksource_register_hz. CC: Richard Henderson CC: Ivan Kokshaysky CC: Matt Turner CC: Thomas Gleixner Signed-off-by: John Stultz --- arch/alpha/kernel/time.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/alpha/kernel/time.c b/arch/alpha/kernel/time.c index c1f3e7cb82a4..33b81108dc83 100644 --- a/arch/alpha/kernel/time.c +++ b/arch/alpha/kernel/time.c @@ -378,8 +378,7 @@ static struct clocksource clocksource_rpcc = { static inline void register_rpcc_clocksource(long cycle_freq) { - clocksource_calc_mult_shift(&clocksource_rpcc, cycle_freq, 4); - clocksource_register(&clocksource_rpcc); + clocksource_register_hz(&clocksource_rpcc, cycle_freq); } #else /* !CONFIG_SMP */ static inline void register_rpcc_clocksource(long cycle_freq) -- cgit v1.2.3 From 39280742efb00ab61ad62486c737fdd3e980c30f Mon Sep 17 00:00:00 2001 From: John Stultz Date: Mon, 26 Apr 2010 20:24:37 -0700 Subject: sparc: convert to clocksource_register_hz/khz This converts the sparc clocksources to use clocksource_register_hz/khz CC: "David S. Miller" CC: Thomas Gleixner Signed-off-by: John Stultz --- arch/sparc/kernel/time_64.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/arch/sparc/kernel/time_64.c b/arch/sparc/kernel/time_64.c index 3bc9c9979b92..58aa27b29984 100644 --- a/arch/sparc/kernel/time_64.c +++ b/arch/sparc/kernel/time_64.c @@ -816,14 +816,12 @@ void __init time_init(void) clocksource_hz2mult(freq, SPARC64_NSEC_PER_CYC_SHIFT); clocksource_tick.name = tick_ops->name; - clocksource_calc_mult_shift(&clocksource_tick, freq, 4); clocksource_tick.read = clocksource_tick_read; + clocksource_register_hz(&clocksource_tick, freq); printk("clocksource: mult[%x] shift[%d]\n", clocksource_tick.mult, clocksource_tick.shift); - clocksource_register(&clocksource_tick); - sparc64_clockevent.name = tick_ops->name; clockevents_calc_mult_shift(&sparc64_clockevent, freq, 4); -- cgit v1.2.3 From 75c4fd8c7862f37eeae5c80f33bbe4dce97571d4 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Mon, 26 Apr 2010 20:23:11 -0700 Subject: mips: convert to clocksource_register_hz/khz This converts the mips clocksources to use clocksource_register_hz/khz CC: Ralf Baechle CC: Thomas Gleixner Signed-off-by: John Stultz --- arch/mips/alchemy/common/time.c | 3 +-- arch/mips/cavium-octeon/csrc-octeon.c | 3 +-- arch/mips/include/asm/time.h | 6 ----- arch/mips/jz4740/time.c | 3 +-- arch/mips/kernel/cevt-txx9.c | 3 +-- arch/mips/kernel/csrc-bcm1480.c | 3 +-- arch/mips/kernel/csrc-ioasic.c | 4 +-- arch/mips/kernel/csrc-powertv.c | 35 +++---------------------- arch/mips/kernel/csrc-r4k.c | 4 +-- arch/mips/kernel/csrc-sb1250.c | 3 +-- arch/mips/kernel/i8253.c | 5 +--- arch/mips/loongson/common/cs5536/cs5536_mfgpt.c | 5 +--- arch/mips/sgi-ip27/ip27-timer.c | 3 +-- 13 files changed, 14 insertions(+), 66 deletions(-) diff --git a/arch/mips/alchemy/common/time.c b/arch/mips/alchemy/common/time.c index 2aecb2fdf982..d5da6adbf634 100644 --- a/arch/mips/alchemy/common/time.c +++ b/arch/mips/alchemy/common/time.c @@ -141,8 +141,7 @@ static int __init alchemy_time_init(unsigned int m2int) goto cntr_err; /* register counter1 clocksource and event device */ - clocksource_set_clock(&au1x_counter1_clocksource, 32768); - clocksource_register(&au1x_counter1_clocksource); + clocksource_register_hz(&au1x_counter1_clocksource, 32768); cd->shift = 32; cd->mult = div_sc(32768, NSEC_PER_SEC, cd->shift); diff --git a/arch/mips/cavium-octeon/csrc-octeon.c b/arch/mips/cavium-octeon/csrc-octeon.c index 26bf71130bf8..29d56afbb02d 100644 --- a/arch/mips/cavium-octeon/csrc-octeon.c +++ b/arch/mips/cavium-octeon/csrc-octeon.c @@ -105,8 +105,7 @@ unsigned long long notrace sched_clock(void) void __init plat_time_init(void) { clocksource_mips.rating = 300; - clocksource_set_clock(&clocksource_mips, octeon_get_clock_rate()); - clocksource_register(&clocksource_mips); + clocksource_register_hz(&clocksource_mips, octeon_get_clock_rate()); } static u64 octeon_udelay_factor; diff --git a/arch/mips/include/asm/time.h b/arch/mips/include/asm/time.h index c7f1bfef1574..bc14447e69b5 100644 --- a/arch/mips/include/asm/time.h +++ b/arch/mips/include/asm/time.h @@ -84,12 +84,6 @@ static inline int init_mips_clocksource(void) #endif } -static inline void clocksource_set_clock(struct clocksource *cs, - unsigned int clock) -{ - clocksource_calc_mult_shift(cs, clock, 4); -} - static inline void clockevent_set_clock(struct clock_event_device *cd, unsigned int clock) { diff --git a/arch/mips/jz4740/time.c b/arch/mips/jz4740/time.c index fe01678d94fd..03dfd4e0da4e 100644 --- a/arch/mips/jz4740/time.c +++ b/arch/mips/jz4740/time.c @@ -121,8 +121,7 @@ void __init plat_time_init(void) clockevents_register_device(&jz4740_clockevent); - clocksource_set_clock(&jz4740_clocksource, clk_rate); - ret = clocksource_register(&jz4740_clocksource); + ret = clocksource_register_hz(&jz4740_clocksource, clk_rate); if (ret) printk(KERN_ERR "Failed to register clocksource: %d\n", ret); diff --git a/arch/mips/kernel/cevt-txx9.c b/arch/mips/kernel/cevt-txx9.c index 0b7377361e22..f0ab92a1b057 100644 --- a/arch/mips/kernel/cevt-txx9.c +++ b/arch/mips/kernel/cevt-txx9.c @@ -51,8 +51,7 @@ void __init txx9_clocksource_init(unsigned long baseaddr, { struct txx9_tmr_reg __iomem *tmrptr; - clocksource_set_clock(&txx9_clocksource.cs, TIMER_CLK(imbusclk)); - clocksource_register(&txx9_clocksource.cs); + clocksource_register_hz(&txx9_clocksource.cs, TIMER_CLK(imbusclk)); tmrptr = ioremap(baseaddr, sizeof(struct txx9_tmr_reg)); __raw_writel(TCR_BASE, &tmrptr->tcr); diff --git a/arch/mips/kernel/csrc-bcm1480.c b/arch/mips/kernel/csrc-bcm1480.c index 51489f8a825e..f96f99c794a3 100644 --- a/arch/mips/kernel/csrc-bcm1480.c +++ b/arch/mips/kernel/csrc-bcm1480.c @@ -49,6 +49,5 @@ void __init sb1480_clocksource_init(void) plldiv = G_BCM1480_SYS_PLL_DIV(__raw_readq(IOADDR(A_SCD_SYSTEM_CFG))); zbbus = ((plldiv >> 1) * 50000000) + ((plldiv & 1) * 25000000); - clocksource_set_clock(cs, zbbus); - clocksource_register(cs); + clocksource_register_hz(cs, zbbus); } diff --git a/arch/mips/kernel/csrc-ioasic.c b/arch/mips/kernel/csrc-ioasic.c index 23da108506b0..46bd7fa98d6c 100644 --- a/arch/mips/kernel/csrc-ioasic.c +++ b/arch/mips/kernel/csrc-ioasic.c @@ -59,7 +59,5 @@ void __init dec_ioasic_clocksource_init(void) printk(KERN_INFO "I/O ASIC clock frequency %dHz\n", freq); clocksource_dec.rating = 200 + freq / 10000000; - clocksource_set_clock(&clocksource_dec, freq); - - clocksource_register(&clocksource_dec); + clocksource_register_hz(&clocksource_dec, freq); } diff --git a/arch/mips/kernel/csrc-powertv.c b/arch/mips/kernel/csrc-powertv.c index a27c16c8690e..2e7c5232da8d 100644 --- a/arch/mips/kernel/csrc-powertv.c +++ b/arch/mips/kernel/csrc-powertv.c @@ -78,9 +78,7 @@ static void __init powertv_c0_hpt_clocksource_init(void) clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000; - clocksource_set_clock(&clocksource_mips, mips_hpt_frequency); - - clocksource_register(&clocksource_mips); + clocksource_register_hz(&clocksource_mips, mips_hpt_frequency); } /** @@ -130,43 +128,16 @@ static struct clocksource clocksource_tim_c = { /** * powertv_tim_c_clocksource_init - set up a clock source for the TIM_C clock * - * The hard part here is coming up with a constant k and shift s such that - * the 48-bit TIM_C value multiplied by k doesn't overflow and that value, - * when shifted right by s, yields the corresponding number of nanoseconds. * We know that TIM_C counts at 27 MHz/8, so each cycle corresponds to - * 1 / (27,000,000/8) seconds. Multiply that by a billion and you get the - * number of nanoseconds. Since the TIM_C value has 48 bits and the math is - * done in 64 bits, avoiding an overflow means that k must be less than - * 64 - 48 = 16 bits. + * 1 / (27,000,000/8) seconds. */ static void __init powertv_tim_c_clocksource_init(void) { - int prescale; - unsigned long dividend; - unsigned long k; - int s; - const int max_k_bits = (64 - 48) - 1; - const unsigned long billion = 1000000000; const unsigned long counts_per_second = 27000000 / 8; - prescale = BITS_PER_LONG - ilog2(billion) - 1; - dividend = billion << prescale; - k = dividend / counts_per_second; - s = ilog2(k) - max_k_bits; - - if (s < 0) - s = prescale; - - else { - k >>= s; - s += prescale; - } - - clocksource_tim_c.mult = k; - clocksource_tim_c.shift = s; clocksource_tim_c.rating = 200; - clocksource_register(&clocksource_tim_c); + clocksource_register_hz(&clocksource_tim_c, counts_per_second); tim_c = (struct tim_c *) asic_reg_addr(tim_ch); } diff --git a/arch/mips/kernel/csrc-r4k.c b/arch/mips/kernel/csrc-r4k.c index e95a3cd48eea..decd1fa38d55 100644 --- a/arch/mips/kernel/csrc-r4k.c +++ b/arch/mips/kernel/csrc-r4k.c @@ -30,9 +30,7 @@ int __init init_r4k_clocksource(void) /* Calculate a somewhat reasonable rating value */ clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000; - clocksource_set_clock(&clocksource_mips, mips_hpt_frequency); - - clocksource_register(&clocksource_mips); + clocksource_register_hz(&clocksource_mips, mips_hpt_frequency); return 0; } diff --git a/arch/mips/kernel/csrc-sb1250.c b/arch/mips/kernel/csrc-sb1250.c index d14d3d1907fa..e9606d907685 100644 --- a/arch/mips/kernel/csrc-sb1250.c +++ b/arch/mips/kernel/csrc-sb1250.c @@ -65,6 +65,5 @@ void __init sb1250_clocksource_init(void) IOADDR(A_SCD_TIMER_REGISTER(SB1250_HPT_NUM, R_SCD_TIMER_CFG))); - clocksource_set_clock(cs, V_SCD_TIMER_FREQ); - clocksource_register(cs); + clocksource_register_hz(cs, V_SCD_TIMER_FREQ); } diff --git a/arch/mips/kernel/i8253.c b/arch/mips/kernel/i8253.c index 2392a7a296d4..9fadd17888d9 100644 --- a/arch/mips/kernel/i8253.c +++ b/arch/mips/kernel/i8253.c @@ -196,8 +196,6 @@ static struct clocksource clocksource_pit = { .rating = 110, .read = pit_read, .mask = CLOCKSOURCE_MASK(32), - .mult = 0, - .shift = 20, }; static int __init init_pit_clocksource(void) @@ -205,7 +203,6 @@ static int __init init_pit_clocksource(void) if (num_possible_cpus() > 1) /* PIT does not scale! */ return 0; - clocksource_pit.mult = clocksource_hz2mult(CLOCK_TICK_RATE, 20); - return clocksource_register(&clocksource_pit); + return clocksource_register_hz(&clocksource_pit, CLOCK_TICK_RATE); } arch_initcall(init_pit_clocksource); diff --git a/arch/mips/loongson/common/cs5536/cs5536_mfgpt.c b/arch/mips/loongson/common/cs5536/cs5536_mfgpt.c index 8c807c965199..0cb1b9760e34 100644 --- a/arch/mips/loongson/common/cs5536/cs5536_mfgpt.c +++ b/arch/mips/loongson/common/cs5536/cs5536_mfgpt.c @@ -201,8 +201,6 @@ static struct clocksource clocksource_mfgpt = { .rating = 120, /* Functional for real use, but not desired */ .read = mfgpt_read, .mask = CLOCKSOURCE_MASK(32), - .mult = 0, - .shift = 22, }; int __init init_mfgpt_clocksource(void) @@ -210,8 +208,7 @@ int __init init_mfgpt_clocksource(void) if (num_possible_cpus() > 1) /* MFGPT does not scale! */ return 0; - clocksource_mfgpt.mult = clocksource_hz2mult(MFGPT_TICK_RATE, 22); - return clocksource_register(&clocksource_mfgpt); + return clocksource_register_hz(&clocksource_mfgpt, MFGPT_TICK_RATE); } arch_initcall(init_mfgpt_clocksource); diff --git a/arch/mips/sgi-ip27/ip27-timer.c b/arch/mips/sgi-ip27/ip27-timer.c index d6802d6d1f82..3cac88382d4c 100644 --- a/arch/mips/sgi-ip27/ip27-timer.c +++ b/arch/mips/sgi-ip27/ip27-timer.c @@ -177,8 +177,7 @@ static void __init hub_rt_clocksource_init(void) { struct clocksource *cs = &hub_rt_clocksource; - clocksource_set_clock(cs, CYCLES_PER_SEC); - clocksource_register(cs); + clocksource_register_hz(cs, CYCLES_PER_SEC); } void __init plat_time_init(void) -- cgit v1.2.3 From a1c57e0fec53defe745e64417eacdbd3618c3e66 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Mon, 26 Apr 2010 20:20:07 -0700 Subject: blackfin: convert to clocksource_register_hz This converts the blackfin clocksource to use clocksource_register_hz. CC: Mike Frysinger CC: Thomas Gleixner Signed-off-by: John Stultz --- arch/blackfin/kernel/time-ts.c | 35 ++--------------------------------- 1 file changed, 2 insertions(+), 33 deletions(-) diff --git a/arch/blackfin/kernel/time-ts.c b/arch/blackfin/kernel/time-ts.c index 8c9a43daf80f..4a013714500b 100644 --- a/arch/blackfin/kernel/time-ts.c +++ b/arch/blackfin/kernel/time-ts.c @@ -23,29 +23,6 @@ #include #include -/* Accelerators for sched_clock() - * convert from cycles(64bits) => nanoseconds (64bits) - * basic equation: - * ns = cycles / (freq / ns_per_sec) - * ns = cycles * (ns_per_sec / freq) - * ns = cycles * (10^9 / (cpu_khz * 10^3)) - * ns = cycles * (10^6 / cpu_khz) - * - * Then we use scaling math (suggested by george@mvista.com) to get: - * ns = cycles * (10^6 * SC / cpu_khz) / SC - * ns = cycles * cyc2ns_scale / SC - * - * And since SC is a constant power of two, we can convert the div - * into a shift. - * - * We can use khz divisor instead of mhz to keep a better precision, since - * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits. - * (mathieu.desnoyers@polymtl.ca) - * - * -johnstul@us.ibm.com "math is hard, lets go shopping!" - */ - -#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */ #if defined(CONFIG_CYCLES_CLOCKSOURCE) @@ -63,7 +40,6 @@ static struct clocksource bfin_cs_cycles = { .rating = 400, .read = bfin_read_cycles, .mask = CLOCKSOURCE_MASK(64), - .shift = CYC2NS_SCALE_FACTOR, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; @@ -75,10 +51,7 @@ static inline unsigned long long bfin_cs_cycles_sched_clock(void) static int __init bfin_cs_cycles_init(void) { - bfin_cs_cycles.mult = \ - clocksource_hz2mult(get_cclk(), bfin_cs_cycles.shift); - - if (clocksource_register(&bfin_cs_cycles)) + if (clocksource_register_hz(&bfin_cs_cycles, get_cclk())) panic("failed to register clocksource"); return 0; @@ -111,7 +84,6 @@ static struct clocksource bfin_cs_gptimer0 = { .rating = 350, .read = bfin_read_gptimer0, .mask = CLOCKSOURCE_MASK(32), - .shift = CYC2NS_SCALE_FACTOR, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; @@ -125,10 +97,7 @@ static int __init bfin_cs_gptimer0_init(void) { setup_gptimer0(); - bfin_cs_gptimer0.mult = \ - clocksource_hz2mult(get_sclk(), bfin_cs_gptimer0.shift); - - if (clocksource_register(&bfin_cs_gptimer0)) + if (clocksource_register_hz(&bfin_cs_gptimer0, get_sclk())) panic("failed to register clocksource"); return 0; -- cgit v1.2.3 From 89c0b8e2520e12d69dafc663dfbd39f8180438ea Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 8 May 2011 18:47:58 +0100 Subject: clocksource: add common i8253 PIT clocksource This is based upon both arch/arm/mach-footbridge/isa-timer.c and arch/x86/kernel/i8253.c. Acked-by: John Stultz Acked-by: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Ralf Baechle Signed-off-by: Russell King --- drivers/Kconfig | 3 ++ drivers/clocksource/Kconfig | 2 + drivers/clocksource/Makefile | 1 + drivers/clocksource/i8253.c | 88 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 94 insertions(+) create mode 100644 drivers/clocksource/Kconfig create mode 100644 drivers/clocksource/i8253.c diff --git a/drivers/Kconfig b/drivers/Kconfig index 177c7d156933..557a469c7aa6 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -119,4 +119,7 @@ source "drivers/platform/Kconfig" source "drivers/clk/Kconfig" source "drivers/hwspinlock/Kconfig" + +source "drivers/clocksource/Kconfig" + endmenu diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig new file mode 100644 index 000000000000..110aeeb52f9a --- /dev/null +++ b/drivers/clocksource/Kconfig @@ -0,0 +1,2 @@ +config CLKSRC_I8253 + bool diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index be61ece6330b..cfb6383b543a 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -6,3 +6,4 @@ obj-$(CONFIG_CS5535_CLOCK_EVENT_SRC) += cs5535-clockevt.o obj-$(CONFIG_SH_TIMER_CMT) += sh_cmt.o obj-$(CONFIG_SH_TIMER_MTU2) += sh_mtu2.o obj-$(CONFIG_SH_TIMER_TMU) += sh_tmu.o +obj-$(CONFIG_CLKSRC_I8253) += i8253.o diff --git a/drivers/clocksource/i8253.c b/drivers/clocksource/i8253.c new file mode 100644 index 000000000000..225c1761b372 --- /dev/null +++ b/drivers/clocksource/i8253.c @@ -0,0 +1,88 @@ +/* + * i8253 PIT clocksource + */ +#include +#include +#include +#include +#include + +#include + +/* + * Since the PIT overflows every tick, its not very useful + * to just read by itself. So use jiffies to emulate a free + * running counter: + */ +static cycle_t i8253_read(struct clocksource *cs) +{ + static int old_count; + static u32 old_jifs; + unsigned long flags; + int count; + u32 jifs; + + raw_spin_lock_irqsave(&i8253_lock, flags); + /* + * Although our caller may have the read side of xtime_lock, + * this is now a seqlock, and we are cheating in this routine + * by having side effects on state that we cannot undo if + * there is a collision on the seqlock and our caller has to + * retry. (Namely, old_jifs and old_count.) So we must treat + * jiffies as volatile despite the lock. We read jiffies + * before latching the timer count to guarantee that although + * the jiffies value might be older than the count (that is, + * the counter may underflow between the last point where + * jiffies was incremented and the point where we latch the + * count), it cannot be newer. + */ + jifs = jiffies; + outb_pit(0x00, PIT_MODE); /* latch the count ASAP */ + count = inb_pit(PIT_CH0); /* read the latched count */ + count |= inb_pit(PIT_CH0) << 8; + + /* VIA686a test code... reset the latch if count > max + 1 */ + if (count > LATCH) { + outb_pit(0x34, PIT_MODE); + outb_pit(PIT_LATCH & 0xff, PIT_CH0); + outb_pit(PIT_LATCH >> 8, PIT_CH0); + count = PIT_LATCH - 1; + } + + /* + * It's possible for count to appear to go the wrong way for a + * couple of reasons: + * + * 1. The timer counter underflows, but we haven't handled the + * resulting interrupt and incremented jiffies yet. + * 2. Hardware problem with the timer, not giving us continuous time, + * the counter does small "jumps" upwards on some Pentium systems, + * (see c't 95/10 page 335 for Neptun bug.) + * + * Previous attempts to handle these cases intelligently were + * buggy, so we just do the simple thing now. + */ + if (count > old_count && jifs == old_jifs) + count = old_count; + + old_count = count; + old_jifs = jifs; + + raw_spin_unlock_irqrestore(&i8253_lock, flags); + + count = (PIT_LATCH - 1) - count; + + return (cycle_t)(jifs * PIT_LATCH) + count; +} + +static struct clocksource i8253_cs = { + .name = "pit", + .rating = 110, + .read = i8253_read, + .mask = CLOCKSOURCE_MASK(32), +}; + +int __init clocksource_i8253_init(void) +{ + return clocksource_register_hz(&i8253_cs, PIT_TICK_RATE); +} -- cgit v1.2.3 From 8c414ff3f4dcdde228c6a668385218290d73a265 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 8 May 2011 18:50:20 +0100 Subject: clocksource: convert footbridge to generic i8253 clocksource Convert the footbridge isa-timer code to use generic i8253 clocksource. Acked-by: John Stultz Acked-by: Thomas Gleixner Signed-off-by: Russell King --- arch/arm/include/asm/i8253.h | 15 ++++++++++++ arch/arm/mach-footbridge/Kconfig | 2 ++ arch/arm/mach-footbridge/isa-timer.c | 45 ++++-------------------------------- include/linux/clocksource.h | 2 ++ 4 files changed, 23 insertions(+), 41 deletions(-) create mode 100644 arch/arm/include/asm/i8253.h diff --git a/arch/arm/include/asm/i8253.h b/arch/arm/include/asm/i8253.h new file mode 100644 index 000000000000..70656b69d5ce --- /dev/null +++ b/arch/arm/include/asm/i8253.h @@ -0,0 +1,15 @@ +#ifndef __ASMARM_I8253_H +#define __ASMARM_I8253_H + +/* i8253A PIT registers */ +#define PIT_MODE 0x43 +#define PIT_CH0 0x40 + +#define PIT_LATCH ((PIT_TICK_RATE + HZ / 2) / HZ) + +extern raw_spinlock_t i8253_lock; + +#define outb_pit outb_p +#define inb_pit inb_p + +#endif diff --git a/arch/arm/mach-footbridge/Kconfig b/arch/arm/mach-footbridge/Kconfig index bdd257921cfb..46adca068f2c 100644 --- a/arch/arm/mach-footbridge/Kconfig +++ b/arch/arm/mach-footbridge/Kconfig @@ -4,6 +4,7 @@ menu "Footbridge Implementations" config ARCH_CATS bool "CATS" + select CLKSRC_I8253 select FOOTBRIDGE_HOST select ISA select ISA_DMA @@ -59,6 +60,7 @@ config ARCH_EBSA285_HOST config ARCH_NETWINDER bool "NetWinder" + select CLKSRC_I8253 select FOOTBRIDGE_HOST select ISA select ISA_DMA diff --git a/arch/arm/mach-footbridge/isa-timer.c b/arch/arm/mach-footbridge/isa-timer.c index 441c6ce0d555..7020f1a3feca 100644 --- a/arch/arm/mach-footbridge/isa-timer.c +++ b/arch/arm/mach-footbridge/isa-timer.c @@ -10,53 +10,16 @@ #include #include #include +#include #include #include - +#include #include #include "common.h" -#define PIT_MODE 0x43 -#define PIT_CH0 0x40 - -#define PIT_LATCH ((PIT_TICK_RATE + HZ / 2) / HZ) - -static cycle_t pit_read(struct clocksource *cs) -{ - unsigned long flags; - static int old_count; - static u32 old_jifs; - int count; - u32 jifs; - - raw_local_irq_save(flags); - - jifs = jiffies; - outb_p(0x00, PIT_MODE); /* latch the count */ - count = inb_p(PIT_CH0); /* read the latched count */ - count |= inb_p(PIT_CH0) << 8; - - if (count > old_count && jifs == old_jifs) - count = old_count; - - old_count = count; - old_jifs = jifs; - - raw_local_irq_restore(flags); - - count = (PIT_LATCH - 1) - count; - - return (cycle_t)(jifs * PIT_LATCH) + count; -} - -static struct clocksource pit_cs = { - .name = "pit", - .rating = 110, - .read = pit_read, - .mask = CLOCKSOURCE_MASK(32), -}; +DEFINE_RAW_SPINLOCK(i8253_lock); static void pit_set_mode(enum clock_event_mode mode, struct clock_event_device *evt) @@ -121,7 +84,7 @@ static void __init isa_timer_init(void) pit_ce.max_delta_ns = clockevent_delta2ns(0x7fff, &pit_ce); pit_ce.min_delta_ns = clockevent_delta2ns(0x000f, &pit_ce); - clocksource_register_hz(&pit_cs, PIT_TICK_RATE); + clocksource_i8253_init(); setup_irq(pit_ce.irq, &pit_timer_irq); clockevents_register_device(&pit_ce); diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index c37b21ad5a3b..f13469b3df86 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -341,4 +341,6 @@ static inline void update_vsyscall_tz(void) extern void timekeeping_notify(struct clocksource *clock); +extern int clocksource_i8253_init(void); + #endif /* _LINUX_CLOCKSOURCE_H */ -- cgit v1.2.3 From 82491451dd25a3abe8496ddbd04ddb3f77d285c2 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 8 May 2011 18:55:19 +0100 Subject: clocksource: convert x86 to generic i8253 clocksource Convert x86 i8253 clocksource code to use generic i8253 clocksource. Acked-by: John Stultz Acked-by: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Ingo Molnar Signed-off-by: Russell King --- arch/x86/Kconfig | 1 + arch/x86/include/asm/i8253.h | 2 ++ arch/x86/kernel/i8253.c | 79 +------------------------------------------- 3 files changed, 4 insertions(+), 78 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index cc6c53a95bfd..01115d54c5be 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -8,6 +8,7 @@ config 64BIT config X86_32 def_bool !64BIT + select CLKSRC_I8253 config X86_64 def_bool 64BIT diff --git a/arch/x86/include/asm/i8253.h b/arch/x86/include/asm/i8253.h index fc1f579fb965..65aaa91d5850 100644 --- a/arch/x86/include/asm/i8253.h +++ b/arch/x86/include/asm/i8253.h @@ -6,6 +6,8 @@ #define PIT_CH0 0x40 #define PIT_CH2 0x42 +#define PIT_LATCH LATCH + extern raw_spinlock_t i8253_lock; extern struct clock_event_device *global_clock_event; diff --git a/arch/x86/kernel/i8253.c b/arch/x86/kernel/i8253.c index 2dfd31597443..b904dfbf6dbc 100644 --- a/arch/x86/kernel/i8253.c +++ b/arch/x86/kernel/i8253.c @@ -117,81 +117,6 @@ void __init setup_pit_timer(void) } #ifndef CONFIG_X86_64 -/* - * Since the PIT overflows every tick, its not very useful - * to just read by itself. So use jiffies to emulate a free - * running counter: - */ -static cycle_t pit_read(struct clocksource *cs) -{ - static int old_count; - static u32 old_jifs; - unsigned long flags; - int count; - u32 jifs; - - raw_spin_lock_irqsave(&i8253_lock, flags); - /* - * Although our caller may have the read side of xtime_lock, - * this is now a seqlock, and we are cheating in this routine - * by having side effects on state that we cannot undo if - * there is a collision on the seqlock and our caller has to - * retry. (Namely, old_jifs and old_count.) So we must treat - * jiffies as volatile despite the lock. We read jiffies - * before latching the timer count to guarantee that although - * the jiffies value might be older than the count (that is, - * the counter may underflow between the last point where - * jiffies was incremented and the point where we latch the - * count), it cannot be newer. - */ - jifs = jiffies; - outb_pit(0x00, PIT_MODE); /* latch the count ASAP */ - count = inb_pit(PIT_CH0); /* read the latched count */ - count |= inb_pit(PIT_CH0) << 8; - - /* VIA686a test code... reset the latch if count > max + 1 */ - if (count > LATCH) { - outb_pit(0x34, PIT_MODE); - outb_pit(LATCH & 0xff, PIT_CH0); - outb_pit(LATCH >> 8, PIT_CH0); - count = LATCH - 1; - } - - /* - * It's possible for count to appear to go the wrong way for a - * couple of reasons: - * - * 1. The timer counter underflows, but we haven't handled the - * resulting interrupt and incremented jiffies yet. - * 2. Hardware problem with the timer, not giving us continuous time, - * the counter does small "jumps" upwards on some Pentium systems, - * (see c't 95/10 page 335 for Neptun bug.) - * - * Previous attempts to handle these cases intelligently were - * buggy, so we just do the simple thing now. - */ - if (count > old_count && jifs == old_jifs) - count = old_count; - - old_count = count; - old_jifs = jifs; - - raw_spin_unlock_irqrestore(&i8253_lock, flags); - - count = (LATCH - 1) - count; - - return (cycle_t)(jifs * LATCH) + count; -} - -static struct clocksource pit_cs = { - .name = "pit", - .rating = 110, - .read = pit_read, - .mask = CLOCKSOURCE_MASK(32), - .mult = 0, - .shift = 20, -}; - static int __init init_pit_clocksource(void) { /* @@ -205,9 +130,7 @@ static int __init init_pit_clocksource(void) pit_ce.mode != CLOCK_EVT_MODE_PERIODIC) return 0; - pit_cs.mult = clocksource_hz2mult(CLOCK_TICK_RATE, pit_cs.shift); - - return clocksource_register(&pit_cs); + return clocksource_i8253_init(); } arch_initcall(init_pit_clocksource); -- cgit v1.2.3 From 798778b8653f64b7b2162ac70eca10367cff6ce8 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 8 May 2011 19:03:03 +0100 Subject: clocksource: convert mips to generic i8253 clocksource Convert MIPS i8253 clocksource code to use generic i8253 clocksource. Acked-by: John Stultz Acked-by: Thomas Gleixner Cc: Ralf Baechle Signed-off-by: Russell King --- arch/mips/Kconfig | 1 + arch/mips/include/asm/i8253.h | 5 +++ arch/mips/kernel/i8253.c | 78 +------------------------------------------ 3 files changed, 7 insertions(+), 77 deletions(-) diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 8e256cc5dcd9..f7f6419e4c84 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -2339,6 +2339,7 @@ config MMU config I8253 bool + select CLKSRC_I8253 select MIPS_EXTERNAL_TIMER config ZONE_DMA32 diff --git a/arch/mips/include/asm/i8253.h b/arch/mips/include/asm/i8253.h index 48bb82372994..9ad011366f73 100644 --- a/arch/mips/include/asm/i8253.h +++ b/arch/mips/include/asm/i8253.h @@ -12,8 +12,13 @@ #define PIT_CH0 0x40 #define PIT_CH2 0x42 +#define PIT_LATCH LATCH + extern raw_spinlock_t i8253_lock; extern void setup_pit_timer(void); +#define inb_pit inb_p +#define outb_pit outb_p + #endif /* __ASM_I8253_H */ diff --git a/arch/mips/kernel/i8253.c b/arch/mips/kernel/i8253.c index 2392a7a296d4..391221b6a6aa 100644 --- a/arch/mips/kernel/i8253.c +++ b/arch/mips/kernel/i8253.c @@ -125,87 +125,11 @@ void __init setup_pit_timer(void) setup_irq(0, &irq0); } -/* - * Since the PIT overflows every tick, its not very useful - * to just read by itself. So use jiffies to emulate a free - * running counter: - */ -static cycle_t pit_read(struct clocksource *cs) -{ - unsigned long flags; - int count; - u32 jifs; - static int old_count; - static u32 old_jifs; - - raw_spin_lock_irqsave(&i8253_lock, flags); - /* - * Although our caller may have the read side of xtime_lock, - * this is now a seqlock, and we are cheating in this routine - * by having side effects on state that we cannot undo if - * there is a collision on the seqlock and our caller has to - * retry. (Namely, old_jifs and old_count.) So we must treat - * jiffies as volatile despite the lock. We read jiffies - * before latching the timer count to guarantee that although - * the jiffies value might be older than the count (that is, - * the counter may underflow between the last point where - * jiffies was incremented and the point where we latch the - * count), it cannot be newer. - */ - jifs = jiffies; - outb_p(0x00, PIT_MODE); /* latch the count ASAP */ - count = inb_p(PIT_CH0); /* read the latched count */ - count |= inb_p(PIT_CH0) << 8; - - /* VIA686a test code... reset the latch if count > max + 1 */ - if (count > LATCH) { - outb_p(0x34, PIT_MODE); - outb_p(LATCH & 0xff, PIT_CH0); - outb(LATCH >> 8, PIT_CH0); - count = LATCH - 1; - } - - /* - * It's possible for count to appear to go the wrong way for a - * couple of reasons: - * - * 1. The timer counter underflows, but we haven't handled the - * resulting interrupt and incremented jiffies yet. - * 2. Hardware problem with the timer, not giving us continuous time, - * the counter does small "jumps" upwards on some Pentium systems, - * (see c't 95/10 page 335 for Neptun bug.) - * - * Previous attempts to handle these cases intelligently were - * buggy, so we just do the simple thing now. - */ - if (count > old_count && jifs == old_jifs) { - count = old_count; - } - old_count = count; - old_jifs = jifs; - - raw_spin_unlock_irqrestore(&i8253_lock, flags); - - count = (LATCH - 1) - count; - - return (cycle_t)(jifs * LATCH) + count; -} - -static struct clocksource clocksource_pit = { - .name = "pit", - .rating = 110, - .read = pit_read, - .mask = CLOCKSOURCE_MASK(32), - .mult = 0, - .shift = 20, -}; - static int __init init_pit_clocksource(void) { if (num_possible_cpus() > 1) /* PIT does not scale! */ return 0; - clocksource_pit.mult = clocksource_hz2mult(CLOCK_TICK_RATE, 20); - return clocksource_register(&clocksource_pit); + return clocksource_i8253_init(); } arch_initcall(init_pit_clocksource); -- cgit v1.2.3