diff options
author | David Brownell <david-b@pacbell.net> | 2008-02-14 19:24:02 (GMT) |
---|---|---|
committer | Haavard Skinnemoen <haavard.skinnemoen@atmel.com> | 2008-04-20 00:40:08 (GMT) |
commit | e723ff666a5da8f7fda4e36ebfeafac2175a5c6e (patch) | |
tree | 53d2b1a0190795977ddccbda2085598d7ea14e43 /arch/avr32 | |
parent | 7e59128f31e0c57d52e86d57730d4c9281494dda (diff) | |
download | linux-fsl-qoriq-e723ff666a5da8f7fda4e36ebfeafac2175a5c6e.tar.xz |
avr32: Generic clockevents support
This combines three patches from David Brownell:
* avr32: tclib support
* avr32: simplify clocksources
* avr32: Turn count/compare into a oneshot clockevent device
Register both TC blocks (instead of just the first one) so that
the AT32/AT91 tclib code will pick them up (instead of just the
avr32-only PIT-style clocksource).
Rename the first one and its resources appropriately.
More cleanups to the cycle counter clocksource code
- Disable all the weak symbol magic; remove the AVR32-only TCB-based
clocksource code (source and header).
- Mark the __init code properly.
- Don't forget to report IRQF_TIMER.
- Make the system work properly with this clocksource, by preventing
use of the CPU "idle" sleep state in the idle loop when it's used.
Package the avr32 count/compare timekeeping support as a oneshot
clockevent device, so it supports NO_HZ and high res timers.
This means it also supports plugging in other clockevent devices
and clocksources.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Diffstat (limited to 'arch/avr32')
-rw-r--r-- | arch/avr32/Kconfig | 5 | ||||
-rw-r--r-- | arch/avr32/kernel/time.c | 209 | ||||
-rw-r--r-- | arch/avr32/mach-at32ap/Makefile | 1 | ||||
-rw-r--r-- | arch/avr32/mach-at32ap/at32ap700x.c | 33 | ||||
-rw-r--r-- | arch/avr32/mach-at32ap/time-tc.c | 218 |
5 files changed, 109 insertions, 357 deletions
diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig index 28e0caf..09ad799 100644 --- a/arch/avr32/Kconfig +++ b/arch/avr32/Kconfig @@ -47,6 +47,9 @@ config RWSEM_GENERIC_SPINLOCK config GENERIC_TIME def_bool y +config GENERIC_CLOCKEVENTS + def_bool y + config RWSEM_XCHGADD_ALGORITHM def_bool n @@ -70,6 +73,8 @@ source "init/Kconfig" menu "System Type and features" +source "kernel/time/Kconfig" + config SUBARCH_AVR32B bool config MMU diff --git a/arch/avr32/kernel/time.c b/arch/avr32/kernel/time.c index bf2f762..00a9862 100644 --- a/arch/avr32/kernel/time.c +++ b/arch/avr32/kernel/time.c @@ -1,16 +1,12 @@ /* * Copyright (C) 2004-2007 Atmel Corporation * - * Based on MIPS implementation arch/mips/kernel/time.c - * Copyright 2001 MontaVista Software Inc. - * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ - #include <linux/clk.h> -#include <linux/clocksource.h> +#include <linux/clockchips.h> #include <linux/time.h> #include <linux/module.h> #include <linux/interrupt.h> @@ -27,13 +23,10 @@ #include <asm/io.h> #include <asm/sections.h> -/* how many counter cycles in a jiffy? */ -static u32 cycles_per_jiffy; +#include <asm/arch/pm.h> -/* the count value for the next timer interrupt */ -static u32 expirelo; -cycle_t __weak read_cycle_count(void) +static cycle_t read_cycle_count(void) { return (cycle_t)sysreg_read(COUNT); } @@ -42,10 +35,11 @@ cycle_t __weak read_cycle_count(void) * The architectural cycle count registers are a fine clocksource unless * the system idle loop use sleep states like "idle": the CPU cycles * measured by COUNT (and COMPARE) don't happen during sleep states. + * Their duration also changes if cpufreq changes the CPU clock rate. * So we rate the clocksource using COUNT as very low quality. */ -struct clocksource __weak clocksource_avr32 = { - .name = "avr32", +static struct clocksource counter = { + .name = "avr32_counter", .rating = 50, .read = read_cycle_count, .mask = CLOCKSOURCE_MASK(32), @@ -53,152 +47,109 @@ struct clocksource __weak clocksource_avr32 = { .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; -irqreturn_t __weak timer_interrupt(int irq, void *dev_id); - -struct irqaction timer_irqaction = { - .handler = timer_interrupt, - .flags = IRQF_DISABLED, - .name = "timer", -}; - -static void avr32_timer_ack(void) -{ - u32 count; - - /* Ack this timer interrupt and set the next one */ - expirelo += cycles_per_jiffy; - /* setting COMPARE to 0 stops the COUNT-COMPARE */ - if (expirelo == 0) { - sysreg_write(COMPARE, expirelo + 1); - } else { - sysreg_write(COMPARE, expirelo); - } - - /* Check to see if we have missed any timer interrupts */ - count = sysreg_read(COUNT); - if ((count - expirelo) < 0x7fffffff) { - expirelo = count + cycles_per_jiffy; - sysreg_write(COMPARE, expirelo); - } -} - -int __weak avr32_hpt_init(void) +static irqreturn_t timer_interrupt(int irq, void *dev_id) { - int ret; - unsigned long mult, shift, count_hz; - - count_hz = clk_get_rate(boot_cpu_data.clk); - shift = clocksource_avr32.shift; - mult = clocksource_hz2mult(count_hz, shift); - clocksource_avr32.mult = mult; + struct clock_event_device *evdev = dev_id; - { - u64 tmp; + /* + * Disable the interrupt until the clockevent subsystem + * reprograms it. + */ + sysreg_write(COMPARE, 0); - tmp = TICK_NSEC; - tmp <<= shift; - tmp += mult / 2; - do_div(tmp, mult); + evdev->event_handler(evdev); + return IRQ_HANDLED; +} - cycles_per_jiffy = tmp; - } +static struct irqaction timer_irqaction = { + .handler = timer_interrupt, + .flags = IRQF_TIMER | IRQF_DISABLED, + .name = "avr32_comparator", +}; - ret = setup_irq(0, &timer_irqaction); - if (ret) { - pr_debug("timer: could not request IRQ 0: %d\n", ret); - return -ENODEV; - } +static int comparator_next_event(unsigned long delta, + struct clock_event_device *evdev) +{ + unsigned long flags; - printk(KERN_INFO "timer: AT32AP COUNT-COMPARE at irq 0, " - "%lu.%03lu MHz\n", - ((count_hz + 500) / 1000) / 1000, - ((count_hz + 500) / 1000) % 1000); + raw_local_irq_save(flags); - return 0; -} + /* The time to read COUNT then update COMPARE must be less + * than the min_delta_ns value for this clockevent source. + */ + sysreg_write(COMPARE, (sysreg_read(COUNT) + delta) ? : 1); -/* - * Taken from MIPS c0_hpt_timer_init(). - * - * The reason COUNT is written twice is probably to make sure we don't get any - * timer interrupts while we are messing with the counter. - */ -int __weak avr32_hpt_start(void) -{ - u32 count = sysreg_read(COUNT); - expirelo = (count / cycles_per_jiffy + 1) * cycles_per_jiffy; - sysreg_write(COUNT, expirelo - cycles_per_jiffy); - sysreg_write(COMPARE, expirelo); - sysreg_write(COUNT, count); + raw_local_irq_restore(flags); return 0; } -/* - * local_timer_interrupt() does profiling and process accounting on a - * per-CPU basis. - * - * In UP mode, it is invoked from the (global) timer_interrupt. - */ -void local_timer_interrupt(int irq, void *dev_id) +static void comparator_mode(enum clock_event_mode mode, + struct clock_event_device *evdev) { - if (current->pid) - profile_tick(CPU_PROFILING); - update_process_times(user_mode(get_irq_regs())); + switch (mode) { + case CLOCK_EVT_MODE_ONESHOT: + pr_debug("%s: start\n", evdev->name); + /* FALLTHROUGH */ + case CLOCK_EVT_MODE_RESUME: + cpu_disable_idle_sleep(); + break; + case CLOCK_EVT_MODE_UNUSED: + case CLOCK_EVT_MODE_SHUTDOWN: + sysreg_write(COMPARE, 0); + pr_debug("%s: stop\n", evdev->name); + cpu_enable_idle_sleep(); + break; + default: + BUG(); + } } -irqreturn_t __weak timer_interrupt(int irq, void *dev_id) -{ - /* ack timer interrupt and try to set next interrupt */ - avr32_timer_ack(); - - /* - * Call the generic timer interrupt handler - */ - write_seqlock(&xtime_lock); - do_timer(1); - write_sequnlock(&xtime_lock); - - /* - * In UP mode, we call local_timer_interrupt() to do profiling - * and process accounting. - * - * SMP is not supported yet. - */ - local_timer_interrupt(irq, dev_id); - - return IRQ_HANDLED; -} +static struct clock_event_device comparator = { + .name = "avr32_comparator", + .features = CLOCK_EVT_FEAT_ONESHOT, + .shift = 16, + .rating = 50, + .cpumask = CPU_MASK_CPU0, + .set_next_event = comparator_next_event, + .set_mode = comparator_mode, +}; void __init time_init(void) { + unsigned long counter_hz; int ret; - /* - * Make sure we don't get any COMPARE interrupts before we can - * handle them. - */ - sysreg_write(COMPARE, 0); - xtime.tv_sec = mktime(2007, 1, 1, 0, 0, 0); xtime.tv_nsec = 0; set_normalized_timespec(&wall_to_monotonic, -xtime.tv_sec, -xtime.tv_nsec); - ret = avr32_hpt_init(); - if (ret) { - pr_debug("timer: failed setup: %d\n", ret); - return; - } + /* figure rate for counter */ + counter_hz = clk_get_rate(boot_cpu_data.clk); + counter.mult = clocksource_hz2mult(counter_hz, counter.shift); - ret = clocksource_register(&clocksource_avr32); + ret = clocksource_register(&counter); if (ret) pr_debug("timer: could not register clocksource: %d\n", ret); - ret = avr32_hpt_start(); - if (ret) { - pr_debug("timer: failed starting: %d\n", ret); - return; + /* setup COMPARE clockevent */ + comparator.mult = div_sc(counter_hz, NSEC_PER_SEC, comparator.shift); + comparator.max_delta_ns = clockevent_delta2ns((u32)~0, &comparator); + comparator.min_delta_ns = clockevent_delta2ns(50, &comparator) + 1; + + sysreg_write(COMPARE, 0); + timer_irqaction.dev_id = &comparator; + + ret = setup_irq(0, &timer_irqaction); + if (ret) + pr_debug("timer: could not request IRQ 0: %d\n", ret); + else { + clockevents_register_device(&comparator); + + pr_info("%s: irq 0, %lu.%03lu MHz\n", comparator.name, + ((counter_hz + 500) / 1000) / 1000, + ((counter_hz + 500) / 1000) % 1000); } } diff --git a/arch/avr32/mach-at32ap/Makefile b/arch/avr32/mach-at32ap/Makefile index 83cab2a..e890094 100644 --- a/arch/avr32/mach-at32ap/Makefile +++ b/arch/avr32/mach-at32ap/Makefile @@ -1,4 +1,3 @@ obj-y += at32ap.o clock.o intc.o extint.o pio.o hsmc.o obj-$(CONFIG_CPU_AT32AP700X) += at32ap700x.o pm-at32ap700x.o -obj-$(CONFIG_CPU_AT32AP700X) += time-tc.o obj-$(CONFIG_CPU_FREQ_AT32AP) += cpufreq.o diff --git a/arch/avr32/mach-at32ap/at32ap700x.c b/arch/avr32/mach-at32ap/at32ap700x.c index 6302bfd..22c302a 100644 --- a/arch/avr32/mach-at32ap/at32ap700x.c +++ b/arch/avr32/mach-at32ap/at32ap700x.c @@ -606,19 +606,32 @@ static inline void set_ebi_sfr_bits(u32 mask) } /* -------------------------------------------------------------------- - * System Timer/Counter (TC) + * Timer/Counter (TC) * -------------------------------------------------------------------- */ -static struct resource at32_systc0_resource[] = { + +static struct resource at32_tcb0_resource[] = { PBMEM(0xfff00c00), IRQ(22), }; -struct platform_device at32_systc0_device = { - .name = "systc", +static struct platform_device at32_tcb0_device = { + .name = "atmel_tcb", .id = 0, - .resource = at32_systc0_resource, - .num_resources = ARRAY_SIZE(at32_systc0_resource), + .resource = at32_tcb0_resource, + .num_resources = ARRAY_SIZE(at32_tcb0_resource), +}; +DEV_CLK(t0_clk, at32_tcb0, pbb, 3); + +static struct resource at32_tcb1_resource[] = { + PBMEM(0xfff01000), + IRQ(23), +}; +static struct platform_device at32_tcb1_device = { + .name = "atmel_tcb", + .id = 1, + .resource = at32_tcb1_resource, + .num_resources = ARRAY_SIZE(at32_tcb1_resource), }; -DEV_CLK(pclk, at32_systc0, pbb, 3); +DEV_CLK(t0_clk, at32_tcb1, pbb, 4); /* -------------------------------------------------------------------- * PIO @@ -670,7 +683,8 @@ void __init at32_add_system_devices(void) platform_device_register(&pdc_device); platform_device_register(&dmaca0_device); - platform_device_register(&at32_systc0_device); + platform_device_register(&at32_tcb0_device); + platform_device_register(&at32_tcb1_device); platform_device_register(&pio0_device); platform_device_register(&pio1_device); @@ -1737,7 +1751,8 @@ struct clk *at32_clock_list[] = { &pio2_mck, &pio3_mck, &pio4_mck, - &at32_systc0_pclk, + &at32_tcb0_t0_clk, + &at32_tcb1_t0_clk, &atmel_usart0_usart, &atmel_usart1_usart, &atmel_usart2_usart, diff --git a/arch/avr32/mach-at32ap/time-tc.c b/arch/avr32/mach-at32ap/time-tc.c deleted file mode 100644 index 1026586..0000000 --- a/arch/avr32/mach-at32ap/time-tc.c +++ /dev/null @@ -1,218 +0,0 @@ -/* - * Copyright (C) 2004-2007 Atmel Corporation - * - * Based on MIPS implementation arch/mips/kernel/time.c - * Copyright 2001 MontaVista Software Inc. - * - * This program is free software; you can redistribute it and/or modify - * it under the terms of the GNU General Public License version 2 as - * published by the Free Software Foundation. - */ - -#include <linux/clk.h> -#include <linux/clocksource.h> -#include <linux/time.h> -#include <linux/module.h> -#include <linux/interrupt.h> -#include <linux/irq.h> -#include <linux/kernel_stat.h> -#include <linux/errno.h> -#include <linux/init.h> -#include <linux/profile.h> -#include <linux/sysdev.h> -#include <linux/err.h> - -#include <asm/div64.h> -#include <asm/sysreg.h> -#include <asm/io.h> -#include <asm/sections.h> - -#include <asm/arch/time.h> - -/* how many counter cycles in a jiffy? */ -static u32 cycles_per_jiffy; - -/* the count value for the next timer interrupt */ -static u32 expirelo; - -/* the I/O registers of the TC module */ -static void __iomem *ioregs; - -cycle_t read_cycle_count(void) -{ - return (cycle_t)timer_read(ioregs, 0, CV); -} - -struct clocksource clocksource_avr32 = { - .name = "avr32", - .rating = 342, - .read = read_cycle_count, - .mask = CLOCKSOURCE_MASK(16), - .shift = 16, - .flags = CLOCK_SOURCE_IS_CONTINUOUS, -}; - -static void avr32_timer_ack(void) -{ - u16 count = expirelo; - - /* Ack this timer interrupt and set the next one, use a u16 - * variable so it will wrap around correctly */ - count += cycles_per_jiffy; - expirelo = count; - timer_write(ioregs, 0, RC, expirelo); - - /* Check to see if we have missed any timer interrupts */ - count = timer_read(ioregs, 0, CV); - if ((count - expirelo) < 0x7fff) { - expirelo = count + cycles_per_jiffy; - timer_write(ioregs, 0, RC, expirelo); - } -} - -u32 avr32_hpt_read(void) -{ - return timer_read(ioregs, 0, CV); -} - -static int avr32_timer_calc_div_and_set_jiffies(struct clk *pclk) -{ - unsigned int cycles_max = (clocksource_avr32.mask + 1) / 2; - unsigned int divs[] = { 4, 8, 16, 32 }; - int divs_size = ARRAY_SIZE(divs); - int i = 0; - unsigned long count_hz; - unsigned long shift; - unsigned long mult; - int clock_div = -1; - u64 tmp; - - shift = clocksource_avr32.shift; - - do { - count_hz = clk_get_rate(pclk) / divs[i]; - mult = clocksource_hz2mult(count_hz, shift); - clocksource_avr32.mult = mult; - - tmp = TICK_NSEC; - tmp <<= shift; - tmp += mult / 2; - do_div(tmp, mult); - - cycles_per_jiffy = tmp; - } while (cycles_per_jiffy > cycles_max && ++i < divs_size); - - clock_div = i + 1; - - if (clock_div > divs_size) { - pr_debug("timer: could not calculate clock divider\n"); - return -EFAULT; - } - - /* Set the clock divider */ - timer_write(ioregs, 0, CMR, TIMER_BF(CMR_TCCLKS, clock_div)); - - return 0; -} - -int avr32_hpt_init(unsigned int count) -{ - struct resource *regs; - struct clk *pclk; - int irq = -1; - int ret = 0; - - ret = -ENXIO; - - irq = platform_get_irq(&at32_systc0_device, 0); - if (irq < 0) { - pr_debug("timer: could not get irq\n"); - goto out_error; - } - - pclk = clk_get(&at32_systc0_device.dev, "pclk"); - if (IS_ERR(pclk)) { - pr_debug("timer: could not get clk: %ld\n", PTR_ERR(pclk)); - goto out_error; - } - clk_enable(pclk); - - regs = platform_get_resource(&at32_systc0_device, IORESOURCE_MEM, 0); - if (!regs) { - pr_debug("timer: could not get resource\n"); - goto out_error_clk; - } - - ioregs = ioremap(regs->start, regs->end - regs->start + 1); - if (!ioregs) { - pr_debug("timer: could not get ioregs\n"); - goto out_error_clk; - } - - ret = avr32_timer_calc_div_and_set_jiffies(pclk); - if (ret) - goto out_error_io; - - ret = setup_irq(irq, &timer_irqaction); - if (ret) { - pr_debug("timer: could not request irq %d: %d\n", - irq, ret); - goto out_error_io; - } - - expirelo = (timer_read(ioregs, 0, CV) / cycles_per_jiffy + 1) - * cycles_per_jiffy; - - /* Enable clock and interrupts on RC compare */ - timer_write(ioregs, 0, CCR, TIMER_BIT(CCR_CLKEN)); - timer_write(ioregs, 0, IER, TIMER_BIT(IER_CPCS)); - /* Set cycles to first interrupt */ - timer_write(ioregs, 0, RC, expirelo); - - printk(KERN_INFO "timer: AT32AP system timer/counter at 0x%p irq %d\n", - ioregs, irq); - - return 0; - -out_error_io: - iounmap(ioregs); -out_error_clk: - clk_put(pclk); -out_error: - return ret; -} - -int avr32_hpt_start(void) -{ - timer_write(ioregs, 0, CCR, TIMER_BIT(CCR_SWTRG)); - return 0; -} - -irqreturn_t timer_interrupt(int irq, void *dev_id) -{ - unsigned int sr = timer_read(ioregs, 0, SR); - - if (sr & TIMER_BIT(SR_CPCS)) { - /* ack timer interrupt and try to set next interrupt */ - avr32_timer_ack(); - - /* - * Call the generic timer interrupt handler - */ - write_seqlock(&xtime_lock); - do_timer(1); - write_sequnlock(&xtime_lock); - - /* - * In UP mode, we call local_timer_interrupt() to do profiling - * and process accounting. - * - * SMP is not supported yet. - */ - local_timer_interrupt(irq, dev_id); - - return IRQ_HANDLED; - } - - return IRQ_NONE; -} |