From: Thomas Gleixner Date: Thu, 11 Oct 2007 09:14:26 +0000 (+0200) Subject: x86_64: prepare shared kernel/hpet.c X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=3940abdf5e7f62bf47c4117f9201c121fbb0ab16;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git x86_64: prepare shared kernel/hpet.c Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- diff --git a/arch/x86_64/kernel/Makefile b/arch/x86_64/kernel/Makefile index fbaba5335b66..e717a324bd8a 100644 --- a/arch/x86_64/kernel/Makefile +++ b/arch/x86_64/kernel/Makefile @@ -8,7 +8,7 @@ obj-y := process.o signal.o entry.o traps_64.o irq.o \ ptrace.o time.o ioport.o ldt.o setup.o i8259_64.o sys_x86_64.o \ x8664_ksyms.o i387.o syscall.o vsyscall.o \ setup64.o bootflag.o e820.o reboot.o quirks.o i8237.o \ - pci-dma_64.o pci-nommu.o alternative.o hpet.o tsc.o bugs.o \ + pci-dma_64.o pci-nommu.o alternative.o hpet_64.o tsc.o bugs.o \ perfctr-watchdog.o obj-$(CONFIG_STACKTRACE) += stacktrace.o diff --git a/arch/x86_64/kernel/hpet.c b/arch/x86_64/kernel/hpet.c deleted file mode 100644 index e2d1b912e154..000000000000 --- a/arch/x86_64/kernel/hpet.c +++ /dev/null @@ -1,493 +0,0 @@ -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include -#include - -#define HPET_MASK 0xFFFFFFFF -#define HPET_SHIFT 22 - -/* FSEC = 10^-15 NSEC = 10^-9 */ -#define FSEC_PER_NSEC 1000000 - -int nohpet __initdata; - -unsigned long hpet_address; -unsigned long hpet_period; /* fsecs / HPET clock */ -unsigned long hpet_tick; /* HPET clocks / interrupt */ - -int hpet_use_timer; /* Use counter of hpet for time keeping, - * otherwise PIT - */ - -#ifdef CONFIG_HPET -static __init int late_hpet_init(void) -{ - struct hpet_data hd; - unsigned int ntimer; - - if (!hpet_address) - return 0; - - memset(&hd, 0, sizeof(hd)); - - ntimer = hpet_readl(HPET_ID); - ntimer = (ntimer & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT; - ntimer++; - - /* - * Register with driver. - * Timer0 and Timer1 is used by platform. - */ - hd.hd_phys_address = hpet_address; - hd.hd_address = (void __iomem *)fix_to_virt(FIX_HPET_BASE); - hd.hd_nirqs = ntimer; - hd.hd_flags = HPET_DATA_PLATFORM; - hpet_reserve_timer(&hd, 0); -#ifdef CONFIG_HPET_EMULATE_RTC - hpet_reserve_timer(&hd, 1); -#endif - hd.hd_irq[0] = HPET_LEGACY_8254; - hd.hd_irq[1] = HPET_LEGACY_RTC; - if (ntimer > 2) { - struct hpet *hpet; - struct hpet_timer *timer; - int i; - - hpet = (struct hpet *) fix_to_virt(FIX_HPET_BASE); - timer = &hpet->hpet_timers[2]; - for (i = 2; i < ntimer; timer++, i++) - hd.hd_irq[i] = (timer->hpet_config & - Tn_INT_ROUTE_CNF_MASK) >> - Tn_INT_ROUTE_CNF_SHIFT; - - } - - hpet_alloc(&hd); - return 0; -} -fs_initcall(late_hpet_init); -#endif - -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_CFG_LEGACY); - 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. - */ - if (hpet_use_timer) { - hpet_writel(HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_SETVAL | - 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; - } -/* - * Go! - */ - - cfg |= HPET_CFG_ENABLE; - hpet_writel(cfg, HPET_CFG); - - return 0; -} - -static cycle_t read_hpet(void) -{ - return (cycle_t)hpet_readl(HPET_COUNTER); -} - -static cycle_t __vsyscall_fn vread_hpet(void) -{ - return readl((void __iomem *)fix_to_virt(VSYSCALL_HPET) + 0xf0); -} - -struct clocksource clocksource_hpet = { - .name = "hpet", - .rating = 250, - .read = read_hpet, - .mask = (cycle_t)HPET_MASK, - .mult = 0, /* set below */ - .shift = HPET_SHIFT, - .flags = CLOCK_SOURCE_IS_CONTINUOUS, - .vread = vread_hpet, -}; - -int __init hpet_arch_init(void) -{ - unsigned int id; - u64 tmp; - - if (!hpet_address) - return -1; - set_fixmap_nocache(FIX_HPET_BASE, hpet_address); - __set_fixmap(VSYSCALL_HPET, 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)) - return -1; - - hpet_period = hpet_readl(HPET_PERIOD); - if (hpet_period < 100000 || hpet_period > 100000000) - return -1; - - hpet_tick = (FSEC_PER_TICK + hpet_period / 2) / hpet_period; - - hpet_use_timer = (id & HPET_ID_LEGSUP); - - /* - * hpet period is in femto seconds per cycle - * so we need to convert this to ns/cyc units - * aproximated by mult/2^shift - * - * fsec/cyc * 1nsec/1000000fsec = nsec/cyc = mult/2^shift - * fsec/cyc * 1ns/1000000fsec * 2^shift = mult - * fsec/cyc * 2^shift * 1nsec/1000000fsec = mult - * (fsec/cyc << shift)/1000000 = mult - * (hpet_period << shift)/FSEC_PER_NSEC = mult - */ - tmp = (u64)hpet_period << HPET_SHIFT; - do_div(tmp, FSEC_PER_NSEC); - clocksource_hpet.mult = (u32)tmp; - clocksource_register(&clocksource_hpet); - - return hpet_timer_stop_set_go(hpet_tick); -} - -int hpet_reenable(void) -{ - return hpet_timer_stop_set_go(hpet_tick); -} - -/* - * calibrate_tsc() calibrates the processor TSC in a very simple way, comparing - * it to the HPET timer of known frequency. - */ - -#define TICK_COUNT 100000000 -#define SMI_THRESHOLD 50000 -#define MAX_TRIES 5 - -/* - * Some platforms take periodic SMI interrupts with 5ms duration. Make sure none - * occurs between the reads of the hpet & TSC. - */ -static void __init read_hpet_tsc(int *hpet, int *tsc) -{ - int tsc1, tsc2, hpet1, i; - - for (i = 0; i < MAX_TRIES; i++) { - tsc1 = get_cycles_sync(); - hpet1 = hpet_readl(HPET_COUNTER); - tsc2 = get_cycles_sync(); - if ((tsc2 - tsc1) < SMI_THRESHOLD) - break; - } - *hpet = hpet1; - *tsc = tsc2; -} - -unsigned int __init hpet_calibrate_tsc(void) -{ - int tsc_start, hpet_start; - int tsc_now, hpet_now; - unsigned long flags; - - local_irq_save(flags); - - read_hpet_tsc(&hpet_start, &tsc_start); - - do { - local_irq_disable(); - read_hpet_tsc(&hpet_now, &tsc_now); - local_irq_restore(flags); - } while ((tsc_now - tsc_start) < TICK_COUNT && - (hpet_now - hpet_start) < TICK_COUNT); - - return (tsc_now - tsc_start) * 1000000000L - / ((hpet_now - hpet_start) * hpet_period / 1000); -} - -#ifdef CONFIG_HPET_EMULATE_RTC -/* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET - * is enabled, we support RTC interrupt functionality in software. - * RTC has 3 kinds of interrupts: - * 1) Update Interrupt - generate an interrupt, every sec, when RTC clock - * is updated - * 2) Alarm Interrupt - generate an interrupt at a specific time of day - * 3) Periodic Interrupt - generate periodic interrupt, with frequencies - * 2Hz-8192Hz (2Hz-64Hz for non-root user) (all freqs in powers of 2) - * (1) and (2) above are implemented using polling at a frequency of - * 64 Hz. The exact frequency is a tradeoff between accuracy and interrupt - * overhead. (DEFAULT_RTC_INT_FREQ) - * For (3), we use interrupts at 64Hz or user specified periodic - * frequency, whichever is higher. - */ -#include - -#define DEFAULT_RTC_INT_FREQ 64 -#define RTC_NUM_INTS 1 - -static unsigned long UIE_on; -static unsigned long prev_update_sec; - -static unsigned long AIE_on; -static struct rtc_time alarm_time; - -static unsigned long PIE_on; -static unsigned long PIE_freq = DEFAULT_RTC_INT_FREQ; -static unsigned long PIE_count; - -static unsigned long hpet_rtc_int_freq; /* RTC interrupt frequency */ -static unsigned int hpet_t1_cmp; /* cached comparator register */ - -int is_hpet_enabled(void) -{ - return hpet_address != 0; -} - -/* - * Timer 1 for RTC, we do not use periodic interrupt feature, - * even if HPET supports periodic interrupts on Timer 1. - * The reason being, to set up a periodic interrupt in HPET, we need to - * stop the main counter. And if we do that everytime someone diables/enables - * RTC, we will have adverse effect on main kernel timer running on Timer 0. - * So, for the time being, simulate the periodic interrupt in software. - * - * hpet_rtc_timer_init() is called for the first time and during subsequent - * interuppts reinit happens through hpet_rtc_timer_reinit(). - */ -int hpet_rtc_timer_init(void) -{ - unsigned int cfg, cnt; - unsigned long flags; - - if (!is_hpet_enabled()) - return 0; - /* - * Set the counter 1 and enable the interrupts. - */ - if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ)) - hpet_rtc_int_freq = PIE_freq; - else - hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ; - - local_irq_save(flags); - - cnt = hpet_readl(HPET_COUNTER); - cnt += ((hpet_tick*HZ)/hpet_rtc_int_freq); - hpet_writel(cnt, HPET_T1_CMP); - hpet_t1_cmp = cnt; - - cfg = hpet_readl(HPET_T1_CFG); - cfg &= ~HPET_TN_PERIODIC; - cfg |= HPET_TN_ENABLE | HPET_TN_32BIT; - hpet_writel(cfg, HPET_T1_CFG); - - local_irq_restore(flags); - - return 1; -} - -static void hpet_rtc_timer_reinit(void) -{ - unsigned int cfg, cnt, ticks_per_int, lost_ints; - - if (unlikely(!(PIE_on | AIE_on | UIE_on))) { - cfg = hpet_readl(HPET_T1_CFG); - cfg &= ~HPET_TN_ENABLE; - hpet_writel(cfg, HPET_T1_CFG); - return; - } - - if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ)) - hpet_rtc_int_freq = PIE_freq; - else - hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ; - - /* It is more accurate to use the comparator value than current count.*/ - ticks_per_int = hpet_tick * HZ / hpet_rtc_int_freq; - hpet_t1_cmp += ticks_per_int; - hpet_writel(hpet_t1_cmp, HPET_T1_CMP); - - /* - * If the interrupt handler was delayed too long, the write above tries - * to schedule the next interrupt in the past and the hardware would - * not interrupt until the counter had wrapped around. - * So we have to check that the comparator wasn't set to a past time. - */ - cnt = hpet_readl(HPET_COUNTER); - if (unlikely((int)(cnt - hpet_t1_cmp) > 0)) { - lost_ints = (cnt - hpet_t1_cmp) / ticks_per_int + 1; - /* Make sure that, even with the time needed to execute - * this code, the next scheduled interrupt has been moved - * back to the future: */ - lost_ints++; - - hpet_t1_cmp += lost_ints * ticks_per_int; - hpet_writel(hpet_t1_cmp, HPET_T1_CMP); - - if (PIE_on) - PIE_count += lost_ints; - - if (printk_ratelimit()) - printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n", - hpet_rtc_int_freq); - } -} - -/* - * The functions below are called from rtc driver. - * Return 0 if HPET is not being used. - * Otherwise do the necessary changes and return 1. - */ -int hpet_mask_rtc_irq_bit(unsigned long bit_mask) -{ - if (!is_hpet_enabled()) - return 0; - - if (bit_mask & RTC_UIE) - UIE_on = 0; - if (bit_mask & RTC_PIE) - PIE_on = 0; - if (bit_mask & RTC_AIE) - AIE_on = 0; - - return 1; -} - -int hpet_set_rtc_irq_bit(unsigned long bit_mask) -{ - int timer_init_reqd = 0; - - if (!is_hpet_enabled()) - return 0; - - if (!(PIE_on | AIE_on | UIE_on)) - timer_init_reqd = 1; - - if (bit_mask & RTC_UIE) { - UIE_on = 1; - } - if (bit_mask & RTC_PIE) { - PIE_on = 1; - PIE_count = 0; - } - if (bit_mask & RTC_AIE) { - AIE_on = 1; - } - - if (timer_init_reqd) - hpet_rtc_timer_init(); - - return 1; -} - -int hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec) -{ - if (!is_hpet_enabled()) - return 0; - - alarm_time.tm_hour = hrs; - alarm_time.tm_min = min; - alarm_time.tm_sec = sec; - - return 1; -} - -int hpet_set_periodic_freq(unsigned long freq) -{ - if (!is_hpet_enabled()) - return 0; - - PIE_freq = freq; - PIE_count = 0; - - return 1; -} - -int hpet_rtc_dropped_irq(void) -{ - if (!is_hpet_enabled()) - return 0; - - return 1; -} - -irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id) -{ - struct rtc_time curr_time; - unsigned long rtc_int_flag = 0; - int call_rtc_interrupt = 0; - - hpet_rtc_timer_reinit(); - - if (UIE_on | AIE_on) { - rtc_get_rtc_time(&curr_time); - } - if (UIE_on) { - if (curr_time.tm_sec != prev_update_sec) { - /* Set update int info, call real rtc int routine */ - call_rtc_interrupt = 1; - rtc_int_flag = RTC_UF; - prev_update_sec = curr_time.tm_sec; - } - } - if (PIE_on) { - PIE_count++; - if (PIE_count >= hpet_rtc_int_freq/PIE_freq) { - /* Set periodic int info, call real rtc int routine */ - call_rtc_interrupt = 1; - rtc_int_flag |= RTC_PF; - PIE_count = 0; - } - } - if (AIE_on) { - if ((curr_time.tm_sec == alarm_time.tm_sec) && - (curr_time.tm_min == alarm_time.tm_min) && - (curr_time.tm_hour == alarm_time.tm_hour)) { - /* Set alarm int info, call real rtc int routine */ - call_rtc_interrupt = 1; - rtc_int_flag |= RTC_AF; - } - } - if (call_rtc_interrupt) { - rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8)); - rtc_interrupt(rtc_int_flag, dev_id); - } - return IRQ_HANDLED; -} -#endif - -static int __init nohpet_setup(char *s) -{ - nohpet = 1; - return 1; -} - -__setup("nohpet", nohpet_setup); diff --git a/arch/x86_64/kernel/hpet_64.c b/arch/x86_64/kernel/hpet_64.c new file mode 100644 index 000000000000..e2d1b912e154 --- /dev/null +++ b/arch/x86_64/kernel/hpet_64.c @@ -0,0 +1,493 @@ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define HPET_MASK 0xFFFFFFFF +#define HPET_SHIFT 22 + +/* FSEC = 10^-15 NSEC = 10^-9 */ +#define FSEC_PER_NSEC 1000000 + +int nohpet __initdata; + +unsigned long hpet_address; +unsigned long hpet_period; /* fsecs / HPET clock */ +unsigned long hpet_tick; /* HPET clocks / interrupt */ + +int hpet_use_timer; /* Use counter of hpet for time keeping, + * otherwise PIT + */ + +#ifdef CONFIG_HPET +static __init int late_hpet_init(void) +{ + struct hpet_data hd; + unsigned int ntimer; + + if (!hpet_address) + return 0; + + memset(&hd, 0, sizeof(hd)); + + ntimer = hpet_readl(HPET_ID); + ntimer = (ntimer & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT; + ntimer++; + + /* + * Register with driver. + * Timer0 and Timer1 is used by platform. + */ + hd.hd_phys_address = hpet_address; + hd.hd_address = (void __iomem *)fix_to_virt(FIX_HPET_BASE); + hd.hd_nirqs = ntimer; + hd.hd_flags = HPET_DATA_PLATFORM; + hpet_reserve_timer(&hd, 0); +#ifdef CONFIG_HPET_EMULATE_RTC + hpet_reserve_timer(&hd, 1); +#endif + hd.hd_irq[0] = HPET_LEGACY_8254; + hd.hd_irq[1] = HPET_LEGACY_RTC; + if (ntimer > 2) { + struct hpet *hpet; + struct hpet_timer *timer; + int i; + + hpet = (struct hpet *) fix_to_virt(FIX_HPET_BASE); + timer = &hpet->hpet_timers[2]; + for (i = 2; i < ntimer; timer++, i++) + hd.hd_irq[i] = (timer->hpet_config & + Tn_INT_ROUTE_CNF_MASK) >> + Tn_INT_ROUTE_CNF_SHIFT; + + } + + hpet_alloc(&hd); + return 0; +} +fs_initcall(late_hpet_init); +#endif + +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_CFG_LEGACY); + 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. + */ + if (hpet_use_timer) { + hpet_writel(HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_SETVAL | + 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; + } +/* + * Go! + */ + + cfg |= HPET_CFG_ENABLE; + hpet_writel(cfg, HPET_CFG); + + return 0; +} + +static cycle_t read_hpet(void) +{ + return (cycle_t)hpet_readl(HPET_COUNTER); +} + +static cycle_t __vsyscall_fn vread_hpet(void) +{ + return readl((void __iomem *)fix_to_virt(VSYSCALL_HPET) + 0xf0); +} + +struct clocksource clocksource_hpet = { + .name = "hpet", + .rating = 250, + .read = read_hpet, + .mask = (cycle_t)HPET_MASK, + .mult = 0, /* set below */ + .shift = HPET_SHIFT, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .vread = vread_hpet, +}; + +int __init hpet_arch_init(void) +{ + unsigned int id; + u64 tmp; + + if (!hpet_address) + return -1; + set_fixmap_nocache(FIX_HPET_BASE, hpet_address); + __set_fixmap(VSYSCALL_HPET, 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)) + return -1; + + hpet_period = hpet_readl(HPET_PERIOD); + if (hpet_period < 100000 || hpet_period > 100000000) + return -1; + + hpet_tick = (FSEC_PER_TICK + hpet_period / 2) / hpet_period; + + hpet_use_timer = (id & HPET_ID_LEGSUP); + + /* + * hpet period is in femto seconds per cycle + * so we need to convert this to ns/cyc units + * aproximated by mult/2^shift + * + * fsec/cyc * 1nsec/1000000fsec = nsec/cyc = mult/2^shift + * fsec/cyc * 1ns/1000000fsec * 2^shift = mult + * fsec/cyc * 2^shift * 1nsec/1000000fsec = mult + * (fsec/cyc << shift)/1000000 = mult + * (hpet_period << shift)/FSEC_PER_NSEC = mult + */ + tmp = (u64)hpet_period << HPET_SHIFT; + do_div(tmp, FSEC_PER_NSEC); + clocksource_hpet.mult = (u32)tmp; + clocksource_register(&clocksource_hpet); + + return hpet_timer_stop_set_go(hpet_tick); +} + +int hpet_reenable(void) +{ + return hpet_timer_stop_set_go(hpet_tick); +} + +/* + * calibrate_tsc() calibrates the processor TSC in a very simple way, comparing + * it to the HPET timer of known frequency. + */ + +#define TICK_COUNT 100000000 +#define SMI_THRESHOLD 50000 +#define MAX_TRIES 5 + +/* + * Some platforms take periodic SMI interrupts with 5ms duration. Make sure none + * occurs between the reads of the hpet & TSC. + */ +static void __init read_hpet_tsc(int *hpet, int *tsc) +{ + int tsc1, tsc2, hpet1, i; + + for (i = 0; i < MAX_TRIES; i++) { + tsc1 = get_cycles_sync(); + hpet1 = hpet_readl(HPET_COUNTER); + tsc2 = get_cycles_sync(); + if ((tsc2 - tsc1) < SMI_THRESHOLD) + break; + } + *hpet = hpet1; + *tsc = tsc2; +} + +unsigned int __init hpet_calibrate_tsc(void) +{ + int tsc_start, hpet_start; + int tsc_now, hpet_now; + unsigned long flags; + + local_irq_save(flags); + + read_hpet_tsc(&hpet_start, &tsc_start); + + do { + local_irq_disable(); + read_hpet_tsc(&hpet_now, &tsc_now); + local_irq_restore(flags); + } while ((tsc_now - tsc_start) < TICK_COUNT && + (hpet_now - hpet_start) < TICK_COUNT); + + return (tsc_now - tsc_start) * 1000000000L + / ((hpet_now - hpet_start) * hpet_period / 1000); +} + +#ifdef CONFIG_HPET_EMULATE_RTC +/* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET + * is enabled, we support RTC interrupt functionality in software. + * RTC has 3 kinds of interrupts: + * 1) Update Interrupt - generate an interrupt, every sec, when RTC clock + * is updated + * 2) Alarm Interrupt - generate an interrupt at a specific time of day + * 3) Periodic Interrupt - generate periodic interrupt, with frequencies + * 2Hz-8192Hz (2Hz-64Hz for non-root user) (all freqs in powers of 2) + * (1) and (2) above are implemented using polling at a frequency of + * 64 Hz. The exact frequency is a tradeoff between accuracy and interrupt + * overhead. (DEFAULT_RTC_INT_FREQ) + * For (3), we use interrupts at 64Hz or user specified periodic + * frequency, whichever is higher. + */ +#include + +#define DEFAULT_RTC_INT_FREQ 64 +#define RTC_NUM_INTS 1 + +static unsigned long UIE_on; +static unsigned long prev_update_sec; + +static unsigned long AIE_on; +static struct rtc_time alarm_time; + +static unsigned long PIE_on; +static unsigned long PIE_freq = DEFAULT_RTC_INT_FREQ; +static unsigned long PIE_count; + +static unsigned long hpet_rtc_int_freq; /* RTC interrupt frequency */ +static unsigned int hpet_t1_cmp; /* cached comparator register */ + +int is_hpet_enabled(void) +{ + return hpet_address != 0; +} + +/* + * Timer 1 for RTC, we do not use periodic interrupt feature, + * even if HPET supports periodic interrupts on Timer 1. + * The reason being, to set up a periodic interrupt in HPET, we need to + * stop the main counter. And if we do that everytime someone diables/enables + * RTC, we will have adverse effect on main kernel timer running on Timer 0. + * So, for the time being, simulate the periodic interrupt in software. + * + * hpet_rtc_timer_init() is called for the first time and during subsequent + * interuppts reinit happens through hpet_rtc_timer_reinit(). + */ +int hpet_rtc_timer_init(void) +{ + unsigned int cfg, cnt; + unsigned long flags; + + if (!is_hpet_enabled()) + return 0; + /* + * Set the counter 1 and enable the interrupts. + */ + if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ)) + hpet_rtc_int_freq = PIE_freq; + else + hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ; + + local_irq_save(flags); + + cnt = hpet_readl(HPET_COUNTER); + cnt += ((hpet_tick*HZ)/hpet_rtc_int_freq); + hpet_writel(cnt, HPET_T1_CMP); + hpet_t1_cmp = cnt; + + cfg = hpet_readl(HPET_T1_CFG); + cfg &= ~HPET_TN_PERIODIC; + cfg |= HPET_TN_ENABLE | HPET_TN_32BIT; + hpet_writel(cfg, HPET_T1_CFG); + + local_irq_restore(flags); + + return 1; +} + +static void hpet_rtc_timer_reinit(void) +{ + unsigned int cfg, cnt, ticks_per_int, lost_ints; + + if (unlikely(!(PIE_on | AIE_on | UIE_on))) { + cfg = hpet_readl(HPET_T1_CFG); + cfg &= ~HPET_TN_ENABLE; + hpet_writel(cfg, HPET_T1_CFG); + return; + } + + if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ)) + hpet_rtc_int_freq = PIE_freq; + else + hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ; + + /* It is more accurate to use the comparator value than current count.*/ + ticks_per_int = hpet_tick * HZ / hpet_rtc_int_freq; + hpet_t1_cmp += ticks_per_int; + hpet_writel(hpet_t1_cmp, HPET_T1_CMP); + + /* + * If the interrupt handler was delayed too long, the write above tries + * to schedule the next interrupt in the past and the hardware would + * not interrupt until the counter had wrapped around. + * So we have to check that the comparator wasn't set to a past time. + */ + cnt = hpet_readl(HPET_COUNTER); + if (unlikely((int)(cnt - hpet_t1_cmp) > 0)) { + lost_ints = (cnt - hpet_t1_cmp) / ticks_per_int + 1; + /* Make sure that, even with the time needed to execute + * this code, the next scheduled interrupt has been moved + * back to the future: */ + lost_ints++; + + hpet_t1_cmp += lost_ints * ticks_per_int; + hpet_writel(hpet_t1_cmp, HPET_T1_CMP); + + if (PIE_on) + PIE_count += lost_ints; + + if (printk_ratelimit()) + printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n", + hpet_rtc_int_freq); + } +} + +/* + * The functions below are called from rtc driver. + * Return 0 if HPET is not being used. + * Otherwise do the necessary changes and return 1. + */ +int hpet_mask_rtc_irq_bit(unsigned long bit_mask) +{ + if (!is_hpet_enabled()) + return 0; + + if (bit_mask & RTC_UIE) + UIE_on = 0; + if (bit_mask & RTC_PIE) + PIE_on = 0; + if (bit_mask & RTC_AIE) + AIE_on = 0; + + return 1; +} + +int hpet_set_rtc_irq_bit(unsigned long bit_mask) +{ + int timer_init_reqd = 0; + + if (!is_hpet_enabled()) + return 0; + + if (!(PIE_on | AIE_on | UIE_on)) + timer_init_reqd = 1; + + if (bit_mask & RTC_UIE) { + UIE_on = 1; + } + if (bit_mask & RTC_PIE) { + PIE_on = 1; + PIE_count = 0; + } + if (bit_mask & RTC_AIE) { + AIE_on = 1; + } + + if (timer_init_reqd) + hpet_rtc_timer_init(); + + return 1; +} + +int hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec) +{ + if (!is_hpet_enabled()) + return 0; + + alarm_time.tm_hour = hrs; + alarm_time.tm_min = min; + alarm_time.tm_sec = sec; + + return 1; +} + +int hpet_set_periodic_freq(unsigned long freq) +{ + if (!is_hpet_enabled()) + return 0; + + PIE_freq = freq; + PIE_count = 0; + + return 1; +} + +int hpet_rtc_dropped_irq(void) +{ + if (!is_hpet_enabled()) + return 0; + + return 1; +} + +irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id) +{ + struct rtc_time curr_time; + unsigned long rtc_int_flag = 0; + int call_rtc_interrupt = 0; + + hpet_rtc_timer_reinit(); + + if (UIE_on | AIE_on) { + rtc_get_rtc_time(&curr_time); + } + if (UIE_on) { + if (curr_time.tm_sec != prev_update_sec) { + /* Set update int info, call real rtc int routine */ + call_rtc_interrupt = 1; + rtc_int_flag = RTC_UF; + prev_update_sec = curr_time.tm_sec; + } + } + if (PIE_on) { + PIE_count++; + if (PIE_count >= hpet_rtc_int_freq/PIE_freq) { + /* Set periodic int info, call real rtc int routine */ + call_rtc_interrupt = 1; + rtc_int_flag |= RTC_PF; + PIE_count = 0; + } + } + if (AIE_on) { + if ((curr_time.tm_sec == alarm_time.tm_sec) && + (curr_time.tm_min == alarm_time.tm_min) && + (curr_time.tm_hour == alarm_time.tm_hour)) { + /* Set alarm int info, call real rtc int routine */ + call_rtc_interrupt = 1; + rtc_int_flag |= RTC_AF; + } + } + if (call_rtc_interrupt) { + rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8)); + rtc_interrupt(rtc_int_flag, dev_id); + } + return IRQ_HANDLED; +} +#endif + +static int __init nohpet_setup(char *s) +{ + nohpet = 1; + return 1; +} + +__setup("nohpet", nohpet_setup);