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timer.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2008 Maxime Bizon <mbizon@freebox.fr>
 */

#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/clk.h>
#include <bcm63xx_cpu.h>
#include <bcm63xx_io.h>
#include <bcm63xx_timer.h>
#include <bcm63xx_regs.h>

static DEFINE_SPINLOCK(timer_reg_lock);
static DEFINE_SPINLOCK(timer_data_lock);
static struct clk *periph_clk;

00024 static struct timer_data {
      void  (*cb)(void *);
      void  *data;
} timer_data[BCM63XX_TIMER_COUNT];

static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
      u32 stat;
      int i;

      spin_lock(&timer_reg_lock);
      stat = bcm_timer_readl(TIMER_IRQSTAT_REG);
      bcm_timer_writel(stat, TIMER_IRQSTAT_REG);
      spin_unlock(&timer_reg_lock);

      for (i = 0; i < BCM63XX_TIMER_COUNT; i++) {
            if (!(stat & TIMER_IRQSTAT_TIMER_CAUSE(i)))
                  continue;

            spin_lock(&timer_data_lock);
            if (!timer_data[i].cb) {
                  spin_unlock(&timer_data_lock);
                  continue;
            }

            timer_data[i].cb(timer_data[i].data);
            spin_unlock(&timer_data_lock);
      }

      return IRQ_HANDLED;
}

int bcm63xx_timer_enable(int id)
{
      u32 reg;
      unsigned long flags;

      if (id >= BCM63XX_TIMER_COUNT)
            return -EINVAL;

      spin_lock_irqsave(&timer_reg_lock, flags);

      reg = bcm_timer_readl(TIMER_CTLx_REG(id));
      reg |= TIMER_CTL_ENABLE_MASK;
      bcm_timer_writel(reg, TIMER_CTLx_REG(id));

      reg = bcm_timer_readl(TIMER_IRQSTAT_REG);
      reg |= TIMER_IRQSTAT_TIMER_IR_EN(id);
      bcm_timer_writel(reg, TIMER_IRQSTAT_REG);

      spin_unlock_irqrestore(&timer_reg_lock, flags);
      return 0;
}

EXPORT_SYMBOL(bcm63xx_timer_enable);

int bcm63xx_timer_disable(int id)
{
      u32 reg;
      unsigned long flags;

      if (id >= BCM63XX_TIMER_COUNT)
            return -EINVAL;

      spin_lock_irqsave(&timer_reg_lock, flags);

      reg = bcm_timer_readl(TIMER_CTLx_REG(id));
      reg &= ~TIMER_CTL_ENABLE_MASK;
      bcm_timer_writel(reg, TIMER_CTLx_REG(id));

      reg = bcm_timer_readl(TIMER_IRQSTAT_REG);
      reg &= ~TIMER_IRQSTAT_TIMER_IR_EN(id);
      bcm_timer_writel(reg, TIMER_IRQSTAT_REG);

      spin_unlock_irqrestore(&timer_reg_lock, flags);
      return 0;
}

EXPORT_SYMBOL(bcm63xx_timer_disable);

int bcm63xx_timer_register(int id, void (*callback)(void *data), void *data)
{
      unsigned long flags;
      int ret;

      if (id >= BCM63XX_TIMER_COUNT || !callback)
            return -EINVAL;

      ret = 0;
      spin_lock_irqsave(&timer_data_lock, flags);
      if (timer_data[id].cb) {
            ret = -EBUSY;
            goto out;
      }

      timer_data[id].cb = callback;
      timer_data[id].data = data;

out:
      spin_unlock_irqrestore(&timer_data_lock, flags);
      return ret;
}

EXPORT_SYMBOL(bcm63xx_timer_register);

void bcm63xx_timer_unregister(int id)
{
      unsigned long flags;

      if (id >= BCM63XX_TIMER_COUNT)
            return;

      spin_lock_irqsave(&timer_data_lock, flags);
      timer_data[id].cb = NULL;
      spin_unlock_irqrestore(&timer_data_lock, flags);
}

EXPORT_SYMBOL(bcm63xx_timer_unregister);

unsigned int bcm63xx_timer_countdown(unsigned int countdown_us)
{
      return (clk_get_rate(periph_clk) / (1000 * 1000)) * countdown_us;
}

EXPORT_SYMBOL(bcm63xx_timer_countdown);

int bcm63xx_timer_set(int id, int monotonic, unsigned int countdown_us)
{
      u32 reg, countdown;
      unsigned long flags;

      if (id >= BCM63XX_TIMER_COUNT)
            return -EINVAL;

      countdown = bcm63xx_timer_countdown(countdown_us);
      if (countdown & ~TIMER_CTL_COUNTDOWN_MASK)
            return -EINVAL;

      spin_lock_irqsave(&timer_reg_lock, flags);
      reg = bcm_timer_readl(TIMER_CTLx_REG(id));

      if (monotonic)
            reg &= ~TIMER_CTL_MONOTONIC_MASK;
      else
            reg |= TIMER_CTL_MONOTONIC_MASK;

      reg &= ~TIMER_CTL_COUNTDOWN_MASK;
      reg |= countdown;
      bcm_timer_writel(reg, TIMER_CTLx_REG(id));

      spin_unlock_irqrestore(&timer_reg_lock, flags);
      return 0;
}

EXPORT_SYMBOL(bcm63xx_timer_set);

int bcm63xx_timer_init(void)
{
      int ret, irq;
      u32 reg;

      reg = bcm_timer_readl(TIMER_IRQSTAT_REG);
      reg &= ~TIMER_IRQSTAT_TIMER0_IR_EN;
      reg &= ~TIMER_IRQSTAT_TIMER1_IR_EN;
      reg &= ~TIMER_IRQSTAT_TIMER2_IR_EN;
      bcm_timer_writel(reg, TIMER_IRQSTAT_REG);

      periph_clk = clk_get(NULL, "periph");
      if (IS_ERR(periph_clk))
            return -ENODEV;

      irq = bcm63xx_get_irq_number(IRQ_TIMER);
      ret = request_irq(irq, timer_interrupt, 0, "bcm63xx_timer", NULL);
      if (ret) {
            printk(KERN_ERR "bcm63xx_timer: failed to register irq\n");
            return ret;
      }

      return 0;
}

arch_initcall(bcm63xx_timer_init);

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