arch/mips/bcm63xx/timer.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2008 Maxime Bizon <mbizon@freebox.fr>
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/err.h>
  11 #include <linux/module.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/clk.h>
  15 #include <bcm63xx_cpu.h>
  16 #include <bcm63xx_io.h>
  17 #include <bcm63xx_timer.h>
  18 #include <bcm63xx_regs.h>
  19
  20 static DEFINE_SPINLOCK(timer_reg_lock);
  21 static DEFINE_SPINLOCK(timer_data_lock);
  22 static struct clk *periph_clk;
  23
  24 static struct timer_data {
  25         void    (*cb)(void *);
  26         void    *data;
  27 } timer_data[BCM63XX_TIMER_COUNT];
  28
  29 static irqreturn_t timer_interrupt(int irq, void *dev_id)
  30 {
  31         u32 stat;
  32         int i;
  33
  34         spin_lock(&timer_reg_lock);
  35         stat = bcm_timer_readl(TIMER_IRQSTAT_REG);
  36         bcm_timer_writel(stat, TIMER_IRQSTAT_REG);
  37         spin_unlock(&timer_reg_lock);
  38
  39         for (i = 0; i < BCM63XX_TIMER_COUNT; i++) {
  40                 if (!(stat & TIMER_IRQSTAT_TIMER_CAUSE(i)))
  41                         continue;
  42
  43                 spin_lock(&timer_data_lock);
  44                 if (!timer_data[i].cb) {
  45                         spin_unlock(&timer_data_lock);
  46                         continue;
  47                 }
  48
  49                 timer_data[i].cb(timer_data[i].data);
  50                 spin_unlock(&timer_data_lock);
  51         }
  52
  53         return IRQ_HANDLED;
  54 }
  55
  56 int bcm63xx_timer_enable(int id)
  57 {
  58         u32 reg;
  59         unsigned long flags;
  60
  61         if (id >= BCM63XX_TIMER_COUNT)
  62                 return -EINVAL;
  63
  64         spin_lock_irqsave(&timer_reg_lock, flags);
  65
  66         reg = bcm_timer_readl(TIMER_CTLx_REG(id));
  67         reg |= TIMER_CTL_ENABLE_MASK;
  68         bcm_timer_writel(reg, TIMER_CTLx_REG(id));
  69
  70         reg = bcm_timer_readl(TIMER_IRQSTAT_REG);
  71         reg |= TIMER_IRQSTAT_TIMER_IR_EN(id);
  72         bcm_timer_writel(reg, TIMER_IRQSTAT_REG);
  73
  74         spin_unlock_irqrestore(&timer_reg_lock, flags);
  75         return 0;
  76 }
  77
  78 EXPORT_SYMBOL(bcm63xx_timer_enable);
  79
  80 int bcm63xx_timer_disable(int id)
  81 {
  82         u32 reg;
  83         unsigned long flags;
  84
  85         if (id >= BCM63XX_TIMER_COUNT)
  86                 return -EINVAL;
  87
  88         spin_lock_irqsave(&timer_reg_lock, flags);
  89
  90         reg = bcm_timer_readl(TIMER_CTLx_REG(id));
  91         reg &= ~TIMER_CTL_ENABLE_MASK;
  92         bcm_timer_writel(reg, TIMER_CTLx_REG(id));
  93
  94         reg = bcm_timer_readl(TIMER_IRQSTAT_REG);
  95         reg &= ~TIMER_IRQSTAT_TIMER_IR_EN(id);
  96         bcm_timer_writel(reg, TIMER_IRQSTAT_REG);
  97
  98         spin_unlock_irqrestore(&timer_reg_lock, flags);
  99         return 0;
 100 }
 101
 102 EXPORT_SYMBOL(bcm63xx_timer_disable);
 103
 104 int bcm63xx_timer_register(int id, void (*callback)(void *data), void *data)
 105 {
 106         unsigned long flags;
 107         int ret;
 108
 109         if (id >= BCM63XX_TIMER_COUNT || !callback)
 110                 return -EINVAL;
 111
 112         ret = 0;
 113         spin_lock_irqsave(&timer_data_lock, flags);
 114         if (timer_data[id].cb) {
 115                 ret = -EBUSY;
 116                 goto out;
 117         }
 118
 119         timer_data[id].cb = callback;
 120         timer_data[id].data = data;
 121
 122 out:
 123         spin_unlock_irqrestore(&timer_data_lock, flags);
 124         return ret;
 125 }
 126
 127 EXPORT_SYMBOL(bcm63xx_timer_register);
 128
 129 void bcm63xx_timer_unregister(int id)
 130 {
 131         unsigned long flags;
 132
 133         if (id >= BCM63XX_TIMER_COUNT)
 134                 return;
 135
 136         spin_lock_irqsave(&timer_data_lock, flags);
 137         timer_data[id].cb = NULL;
 138         spin_unlock_irqrestore(&timer_data_lock, flags);
 139 }
 140
 141 EXPORT_SYMBOL(bcm63xx_timer_unregister);
 142
 143 unsigned int bcm63xx_timer_countdown(unsigned int countdown_us)
 144 {
 145         return (clk_get_rate(periph_clk) / (1000 * 1000)) * countdown_us;
 146 }
 147
 148 EXPORT_SYMBOL(bcm63xx_timer_countdown);
 149
 150 int bcm63xx_timer_set(int id, int monotonic, unsigned int countdown_us)
 151 {
 152         u32 reg, countdown;
 153         unsigned long flags;
 154
 155         if (id >= BCM63XX_TIMER_COUNT)
 156                 return -EINVAL;
 157
 158         countdown = bcm63xx_timer_countdown(countdown_us);
 159         if (countdown & ~TIMER_CTL_COUNTDOWN_MASK)
 160                 return -EINVAL;
 161
 162         spin_lock_irqsave(&timer_reg_lock, flags);
 163         reg = bcm_timer_readl(TIMER_CTLx_REG(id));
 164
 165         if (monotonic)
 166                 reg &= ~TIMER_CTL_MONOTONIC_MASK;
 167         else
 168                 reg |= TIMER_CTL_MONOTONIC_MASK;
 169
 170         reg &= ~TIMER_CTL_COUNTDOWN_MASK;
 171         reg |= countdown;
 172         bcm_timer_writel(reg, TIMER_CTLx_REG(id));
 173
 174         spin_unlock_irqrestore(&timer_reg_lock, flags);
 175         return 0;
 176 }
 177
 178 EXPORT_SYMBOL(bcm63xx_timer_set);
 179
 180 int bcm63xx_timer_init(void)
 181 {
 182         int ret, irq;
 183         u32 reg;
 184
 185         reg = bcm_timer_readl(TIMER_IRQSTAT_REG);
 186         reg &= ~TIMER_IRQSTAT_TIMER0_IR_EN;
 187         reg &= ~TIMER_IRQSTAT_TIMER1_IR_EN;
 188         reg &= ~TIMER_IRQSTAT_TIMER2_IR_EN;
 189         bcm_timer_writel(reg, TIMER_IRQSTAT_REG);
 190
 191         periph_clk = clk_get(NULL, "periph");
 192         if (IS_ERR(periph_clk))
 193                 return -ENODEV;
 194
 195         irq = bcm63xx_get_irq_number(IRQ_TIMER);
 196         ret = request_irq(irq, timer_interrupt, 0, "bcm63xx_timer", NULL);
 197         if (ret) {
 198                 printk(KERN_ERR "bcm63xx_timer: failed to register irq\n");
 199                 return ret;
 200         }
 201
 202         return 0;
 203 }
 204
 205 arch_initcall(bcm63xx_timer_init);