Quelle  timer.c   Sprache: 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/init.h>
#include <linux/export.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_RAW_SPINLOCK(timer_reg_lock);
static DEFINE_RAW_SPINLOCK(timer_data_lock);
static struct clk *periph_clk;

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;

 raw_spin_lock(&timer_reg_lock);
 stat = bcm_timer_readl(TIMER_IRQSTAT_REG);
 bcm_timer_writel(stat, TIMER_IRQSTAT_REG);
 raw_spin_unlock(&timer_reg_lock);

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

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

  timer_data[i].cb(timer_data[i].data);
  raw_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;

 raw_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);

 raw_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;

 raw_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);

 raw_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;
 raw_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:
 raw_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;

 raw_spin_lock_irqsave(&timer_data_lock, flags);
 timer_data[id].cb = NULL;
 raw_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;

 raw_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));

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

EXPORT_SYMBOL(bcm63xx_timer_set);

static 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) {
  pr_err("%s: failed to register irq\n", __func__);
  return ret;
 }

 return 0;
}

arch_initcall(bcm63xx_timer_init);