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authorDavid Brownell <david-b@pacbell.net>2008-02-14 11:24:02 -0800
committerHaavard Skinnemoen <haavard.skinnemoen@atmel.com>2008-04-19 20:40:08 -0400
commite723ff666a5da8f7fda4e36ebfeafac2175a5c6e (patch)
tree53d2b1a0190795977ddccbda2085598d7ea14e43 /arch/avr32
parent7e59128f31e0c57d52e86d57730d4c9281494dda (diff)
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/Kconfig5
-rw-r--r--arch/avr32/kernel/time.c209
-rw-r--r--arch/avr32/mach-at32ap/Makefile1
-rw-r--r--arch/avr32/mach-at32ap/at32ap700x.c33
-rw-r--r--arch/avr32/mach-at32ap/time-tc.c218
5 files changed, 109 insertions, 357 deletions
diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig
index 28e0caf4156c..09ad7995080c 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 bf2f762e6a47..00a9862380ff 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 83cab2abb6c3..e89009439e4a 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 6302bfd58514..22c302ad9b3f 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 10265863c982..000000000000
--- 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;
-}