diff options
Diffstat (limited to 'arch/arm/mach-at91/at91sam926x_time.c')
| -rw-r--r-- | arch/arm/mach-at91/at91sam926x_time.c | 294 |
1 files changed, 0 insertions, 294 deletions
diff --git a/arch/arm/mach-at91/at91sam926x_time.c b/arch/arm/mach-at91/at91sam926x_time.c deleted file mode 100644 index 0a9e2fc8f796..000000000000 --- a/arch/arm/mach-at91/at91sam926x_time.c +++ /dev/null @@ -1,294 +0,0 @@ -/* - * at91sam926x_time.c - Periodic Interval Timer (PIT) for at91sam926x - * - * Copyright (C) 2005-2006 M. Amine SAYA, ATMEL Rousset, France - * Revision 2005 M. Nicolas Diremdjian, ATMEL Rousset, France - * Converted to ClockSource/ClockEvents by David Brownell. - * - * 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/interrupt.h> -#include <linux/irq.h> -#include <linux/kernel.h> -#include <linux/clk.h> -#include <linux/clockchips.h> -#include <linux/of.h> -#include <linux/of_address.h> -#include <linux/of_irq.h> - -#include <asm/mach/time.h> -#include <mach/hardware.h> - -#define AT91_PIT_MR 0x00 /* Mode Register */ -#define AT91_PIT_PITIEN (1 << 25) /* Timer Interrupt Enable */ -#define AT91_PIT_PITEN (1 << 24) /* Timer Enabled */ -#define AT91_PIT_PIV (0xfffff) /* Periodic Interval Value */ - -#define AT91_PIT_SR 0x04 /* Status Register */ -#define AT91_PIT_PITS (1 << 0) /* Timer Status */ - -#define AT91_PIT_PIVR 0x08 /* Periodic Interval Value Register */ -#define AT91_PIT_PIIR 0x0c /* Periodic Interval Image Register */ -#define AT91_PIT_PICNT (0xfff << 20) /* Interval Counter */ -#define AT91_PIT_CPIV (0xfffff) /* Inverval Value */ - -#define PIT_CPIV(x) ((x) & AT91_PIT_CPIV) -#define PIT_PICNT(x) (((x) & AT91_PIT_PICNT) >> 20) - -static u32 pit_cycle; /* write-once */ -static u32 pit_cnt; /* access only w/system irq blocked */ -static void __iomem *pit_base_addr __read_mostly; -static struct clk *mck; - -static inline unsigned int pit_read(unsigned int reg_offset) -{ - return __raw_readl(pit_base_addr + reg_offset); -} - -static inline void pit_write(unsigned int reg_offset, unsigned long value) -{ - __raw_writel(value, pit_base_addr + reg_offset); -} - -/* - * Clocksource: just a monotonic counter of MCK/16 cycles. - * We don't care whether or not PIT irqs are enabled. - */ -static cycle_t read_pit_clk(struct clocksource *cs) -{ - unsigned long flags; - u32 elapsed; - u32 t; - - raw_local_irq_save(flags); - elapsed = pit_cnt; - t = pit_read(AT91_PIT_PIIR); - raw_local_irq_restore(flags); - - elapsed += PIT_PICNT(t) * pit_cycle; - elapsed += PIT_CPIV(t); - return elapsed; -} - -static struct clocksource pit_clk = { - .name = "pit", - .rating = 175, - .read = read_pit_clk, - .flags = CLOCK_SOURCE_IS_CONTINUOUS, -}; - - -/* - * Clockevent device: interrupts every 1/HZ (== pit_cycles * MCK/16) - */ -static void -pit_clkevt_mode(enum clock_event_mode mode, struct clock_event_device *dev) -{ - switch (mode) { - case CLOCK_EVT_MODE_PERIODIC: - /* update clocksource counter */ - pit_cnt += pit_cycle * PIT_PICNT(pit_read(AT91_PIT_PIVR)); - pit_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN - | AT91_PIT_PITIEN); - break; - case CLOCK_EVT_MODE_ONESHOT: - BUG(); - /* FALLTHROUGH */ - case CLOCK_EVT_MODE_SHUTDOWN: - case CLOCK_EVT_MODE_UNUSED: - /* disable irq, leaving the clocksource active */ - pit_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN); - break; - case CLOCK_EVT_MODE_RESUME: - break; - } -} - -static void at91sam926x_pit_suspend(struct clock_event_device *cedev) -{ - /* Disable timer */ - pit_write(AT91_PIT_MR, 0); -} - -static void at91sam926x_pit_reset(void) -{ - /* Disable timer and irqs */ - pit_write(AT91_PIT_MR, 0); - - /* Clear any pending interrupts, wait for PIT to stop counting */ - while (PIT_CPIV(pit_read(AT91_PIT_PIVR)) != 0) - cpu_relax(); - - /* Start PIT but don't enable IRQ */ - pit_write(AT91_PIT_MR, (pit_cycle - 1) | AT91_PIT_PITEN); -} - -static void at91sam926x_pit_resume(struct clock_event_device *cedev) -{ - at91sam926x_pit_reset(); -} - -static struct clock_event_device pit_clkevt = { - .name = "pit", - .features = CLOCK_EVT_FEAT_PERIODIC, - .shift = 32, - .rating = 100, - .set_mode = pit_clkevt_mode, - .suspend = at91sam926x_pit_suspend, - .resume = at91sam926x_pit_resume, -}; - - -/* - * IRQ handler for the timer. - */ -static irqreturn_t at91sam926x_pit_interrupt(int irq, void *dev_id) -{ - /* - * irqs should be disabled here, but as the irq is shared they are only - * guaranteed to be off if the timer irq is registered first. - */ - WARN_ON_ONCE(!irqs_disabled()); - - /* The PIT interrupt may be disabled, and is shared */ - if ((pit_clkevt.mode == CLOCK_EVT_MODE_PERIODIC) - && (pit_read(AT91_PIT_SR) & AT91_PIT_PITS)) { - unsigned nr_ticks; - - /* Get number of ticks performed before irq, and ack it */ - nr_ticks = PIT_PICNT(pit_read(AT91_PIT_PIVR)); - do { - pit_cnt += pit_cycle; - pit_clkevt.event_handler(&pit_clkevt); - nr_ticks--; - } while (nr_ticks); - - return IRQ_HANDLED; - } - - return IRQ_NONE; -} - -static struct irqaction at91sam926x_pit_irq = { - .name = "at91_tick", - .flags = IRQF_SHARED | IRQF_TIMER | IRQF_IRQPOLL, - .handler = at91sam926x_pit_interrupt, - .irq = NR_IRQS_LEGACY + AT91_ID_SYS, -}; - -#ifdef CONFIG_OF -static struct of_device_id pit_timer_ids[] = { - { .compatible = "atmel,at91sam9260-pit" }, - { /* sentinel */ } -}; - -static int __init of_at91sam926x_pit_init(void) -{ - struct device_node *np; - int ret; - - np = of_find_matching_node(NULL, pit_timer_ids); - if (!np) - goto err; - - pit_base_addr = of_iomap(np, 0); - if (!pit_base_addr) - goto node_err; - - mck = of_clk_get(np, 0); - - /* Get the interrupts property */ - ret = irq_of_parse_and_map(np, 0); - if (!ret) { - pr_crit("AT91: PIT: Unable to get IRQ from DT\n"); - if (!IS_ERR(mck)) - clk_put(mck); - goto ioremap_err; - } - at91sam926x_pit_irq.irq = ret; - - of_node_put(np); - - return 0; - -ioremap_err: - iounmap(pit_base_addr); -node_err: - of_node_put(np); -err: - return -EINVAL; -} -#else -static int __init of_at91sam926x_pit_init(void) -{ - return -EINVAL; -} -#endif - -/* - * Set up both clocksource and clockevent support. - */ -void __init at91sam926x_pit_init(void) -{ - unsigned long pit_rate; - unsigned bits; - int ret; - - mck = ERR_PTR(-ENOENT); - - /* For device tree enabled device: initialize here */ - of_at91sam926x_pit_init(); - - /* - * Use our actual MCK to figure out how many MCK/16 ticks per - * 1/HZ period (instead of a compile-time constant LATCH). - */ - if (IS_ERR(mck)) - mck = clk_get(NULL, "mck"); - - if (IS_ERR(mck)) - panic("AT91: PIT: Unable to get mck clk\n"); - pit_rate = clk_get_rate(mck) / 16; - pit_cycle = (pit_rate + HZ/2) / HZ; - WARN_ON(((pit_cycle - 1) & ~AT91_PIT_PIV) != 0); - - /* Initialize and enable the timer */ - at91sam926x_pit_reset(); - - /* - * Register clocksource. The high order bits of PIV are unused, - * so this isn't a 32-bit counter unless we get clockevent irqs. - */ - bits = 12 /* PICNT */ + ilog2(pit_cycle) /* PIV */; - pit_clk.mask = CLOCKSOURCE_MASK(bits); - clocksource_register_hz(&pit_clk, pit_rate); - - /* Set up irq handler */ - ret = setup_irq(at91sam926x_pit_irq.irq, &at91sam926x_pit_irq); - if (ret) - pr_crit("AT91: PIT: Unable to setup IRQ\n"); - - /* Set up and register clockevents */ - pit_clkevt.mult = div_sc(pit_rate, NSEC_PER_SEC, pit_clkevt.shift); - pit_clkevt.cpumask = cpumask_of(0); - clockevents_register_device(&pit_clkevt); -} - -void __init at91sam926x_ioremap_pit(u32 addr) -{ -#if defined(CONFIG_OF) - struct device_node *np = - of_find_matching_node(NULL, pit_timer_ids); - - if (np) { - of_node_put(np); - return; - } -#endif - pit_base_addr = ioremap(addr, 16); - - if (!pit_base_addr) - panic("Impossible to ioremap PIT\n"); -} |