LXR linux/arch/mips/kernel/cevt-bcm1480.c

   1/*
   2 * Copyright (C) 2000,2001,2004 Broadcom Corporation
   3 *
   4 * This program is free software; you can redistribute it and/or
   5 * modify it under the terms of the GNU General Public License
   6 * as published by the Free Software Foundation; either version 2
   7 * of the License, or (at your option) any later version.
   8 *
   9 * This program is distributed in the hope that it will be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write to the Free Software
  16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17 */
  18#include <linux/clockchips.h>
  19#include <linux/interrupt.h>
  20#include <linux/percpu.h>
  21#include <linux/smp.h>
  22#include <linux/irq.h>
  23
  24#include <asm/addrspace.h>
  25#include <asm/io.h>
  26#include <asm/time.h>
  27
  28#include <asm/sibyte/bcm1480_regs.h>
  29#include <asm/sibyte/sb1250_regs.h>
  30#include <asm/sibyte/bcm1480_int.h>
  31#include <asm/sibyte/bcm1480_scd.h>
  32
  33#include <asm/sibyte/sb1250.h>
  34
  35#define IMR_IP2_VAL     K_BCM1480_INT_MAP_I0
  36#define IMR_IP3_VAL     K_BCM1480_INT_MAP_I1
  37#define IMR_IP4_VAL     K_BCM1480_INT_MAP_I2
  38
  39/*
  40 * The general purpose timer ticks at 1MHz independent if
  41 * the rest of the system
  42 */
  43static void sibyte_set_mode(enum clock_event_mode mode,
  44                           struct clock_event_device *evt)
  45{
  46        unsigned int cpu = smp_processor_id();
  47        void __iomem *cfg, *init;
  48
  49        cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
  50        init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));
  51
  52        switch (mode) {
  53        case CLOCK_EVT_MODE_PERIODIC:
  54                __raw_writeq(0, cfg);
  55                __raw_writeq((V_SCD_TIMER_FREQ / HZ) - 1, init);
  56                __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
  57                             cfg);
  58                break;
  59
  60        case CLOCK_EVT_MODE_ONESHOT:
  61                /* Stop the timer until we actually program a shot */
  62        case CLOCK_EVT_MODE_SHUTDOWN:
  63                __raw_writeq(0, cfg);
  64                break;
  65
  66        case CLOCK_EVT_MODE_UNUSED:     /* shuddup gcc */
  67        case CLOCK_EVT_MODE_RESUME:
  68                ;
  69        }
  70}
  71
  72static int sibyte_next_event(unsigned long delta, struct clock_event_device *cd)
  73{
  74        unsigned int cpu = smp_processor_id();
  75        void __iomem *cfg, *init;
  76
  77        cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
  78        init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));
  79
  80        __raw_writeq(0, cfg);
  81        __raw_writeq(delta - 1, init);
  82        __raw_writeq(M_SCD_TIMER_ENABLE, cfg);
  83
  84        return 0;
  85}
  86
  87static irqreturn_t sibyte_counter_handler(int irq, void *dev_id)
  88{
  89        unsigned int cpu = smp_processor_id();
  90        struct clock_event_device *cd = dev_id;
  91        void __iomem *cfg;
  92        unsigned long tmode;
  93
  94        if (cd->mode == CLOCK_EVT_MODE_PERIODIC)
  95                tmode = M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS;
  96        else
  97                tmode = 0;
  98
  99        /* ACK interrupt */
 100        cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
 101        ____raw_writeq(tmode, cfg);
 102
 103        cd->event_handler(cd);
 104
 105        return IRQ_HANDLED;
 106}
 107
 108static DEFINE_PER_CPU(struct clock_event_device, sibyte_hpt_clockevent);
 109static DEFINE_PER_CPU(struct irqaction, sibyte_hpt_irqaction);
 110static DEFINE_PER_CPU(char [18], sibyte_hpt_name);
 111
 112void sb1480_clockevent_init(void)
 113{
 114        unsigned int cpu = smp_processor_id();
 115        unsigned int irq = K_BCM1480_INT_TIMER_0 + cpu;
 116        struct irqaction *action = &per_cpu(sibyte_hpt_irqaction, cpu);
 117        struct clock_event_device *cd = &per_cpu(sibyte_hpt_clockevent, cpu);
 118        unsigned char *name = per_cpu(sibyte_hpt_name, cpu);
 119
 120        BUG_ON(cpu > 3);        /* Only have 4 general purpose timers */
 121
 122        sprintf(name, "bcm1480-counter-%d", cpu);
 123        cd->name                = name;
 124        cd->features            = CLOCK_EVT_FEAT_PERIODIC |
 125                                  CLOCK_EVT_FEAT_ONESHOT;
 126        clockevent_set_clock(cd, V_SCD_TIMER_FREQ);
 127        cd->max_delta_ns        = clockevent_delta2ns(0x7fffff, cd);
 128        cd->min_delta_ns        = clockevent_delta2ns(2, cd);
 129        cd->rating              = 200;
 130        cd->irq                 = irq;
 131        cd->cpumask             = cpumask_of(cpu);
 132        cd->set_next_event      = sibyte_next_event;
 133        cd->set_mode            = sibyte_set_mode;
 134        clockevents_register_device(cd);
 135
 136        bcm1480_mask_irq(cpu, irq);
 137
 138        /*
 139         * Map the timer interrupt to IP[4] of this cpu
 140         */
 141        __raw_writeq(IMR_IP4_VAL,
 142                     IOADDR(A_BCM1480_IMR_REGISTER(cpu,
 143                        R_BCM1480_IMR_INTERRUPT_MAP_BASE_H) + (irq << 3)));
 144
 145        bcm1480_unmask_irq(cpu, irq);
 146
 147        action->handler = sibyte_counter_handler;
 148        action->flags   = IRQF_PERCPU | IRQF_TIMER;
 149        action->name    = name;
 150        action->dev_id  = cd;
 151
 152        irq_set_affinity(irq, cpumask_of(cpu));
 153        setup_irq(irq, action);
 154}
 155