arch/mips/kernel/cevt-sb1250.c

   1 /*
   2  * Copyright (C) 2000, 2001 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/irq.h>
  21 #include <linux/percpu.h>
  22 #include <linux/smp.h>
  23
  24 #include <asm/addrspace.h>
  25 #include <asm/io.h>
  26 #include <asm/time.h>
  27
  28 #include <asm/sibyte/sb1250.h>
  29 #include <asm/sibyte/sb1250_regs.h>
  30 #include <asm/sibyte/sb1250_int.h>
  31 #include <asm/sibyte/sb1250_scd.h>
  32
  33 #define IMR_IP2_VAL     K_INT_MAP_I0
  34 #define IMR_IP3_VAL     K_INT_MAP_I1
  35 #define IMR_IP4_VAL     K_INT_MAP_I2
  36
  37 /*
  38  * The general purpose timer ticks at 1MHz independent if
  39  * the rest of the system
  40  */
  41 static void sibyte_set_mode(enum clock_event_mode mode,
  42                            struct clock_event_device *evt)
  43 {
  44         unsigned int cpu = smp_processor_id();
  45         void __iomem *cfg, *init;
  46
  47         cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
  48         init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));
  49
  50         switch (mode) {
  51         case CLOCK_EVT_MODE_PERIODIC:
  52                 __raw_writeq(0, cfg);
  53                 __raw_writeq((V_SCD_TIMER_FREQ / HZ) - 1, init);
  54                 __raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
  55                              cfg);
  56                 break;
  57
  58         case CLOCK_EVT_MODE_ONESHOT:
  59                 /* Stop the timer until we actually program a shot */
  60         case CLOCK_EVT_MODE_SHUTDOWN:
  61                 __raw_writeq(0, cfg);
  62                 break;
  63
  64         case CLOCK_EVT_MODE_UNUSED:     /* shuddup gcc */
  65         case CLOCK_EVT_MODE_RESUME:
  66                 ;
  67         }
  68 }
  69
  70 static int sibyte_next_event(unsigned long delta, struct clock_event_device *cd)
  71 {
  72         unsigned int cpu = smp_processor_id();
  73         void __iomem *cfg, *init;
  74
  75         cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
  76         init = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_INIT));
  77
  78         __raw_writeq(0, cfg);
  79         __raw_writeq(delta - 1, init);
  80         __raw_writeq(M_SCD_TIMER_ENABLE, cfg);
  81
  82         return 0;
  83 }
  84
  85 static irqreturn_t sibyte_counter_handler(int irq, void *dev_id)
  86 {
  87         unsigned int cpu = smp_processor_id();
  88         struct clock_event_device *cd = dev_id;
  89         void __iomem *cfg;
  90         unsigned long tmode;
  91
  92         if (cd->mode == CLOCK_EVT_MODE_PERIODIC)
  93                 tmode = M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS;
  94         else
  95                 tmode = 0;
  96
  97         /* ACK interrupt */
  98         cfg = IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG));
  99         ____raw_writeq(tmode, cfg);
 100
 101         cd->event_handler(cd);
 102
 103         return IRQ_HANDLED;
 104 }
 105
 106 static DEFINE_PER_CPU(struct clock_event_device, sibyte_hpt_clockevent);
 107 static DEFINE_PER_CPU(struct irqaction, sibyte_hpt_irqaction);
 108 static DEFINE_PER_CPU(char [18], sibyte_hpt_name);
 109
 110 void sb1250_clockevent_init(void)
 111 {
 112         unsigned int cpu = smp_processor_id();
 113         unsigned int irq = K_INT_TIMER_0 + cpu;
 114         struct irqaction *action = &per_cpu(sibyte_hpt_irqaction, cpu);
 115         struct clock_event_device *cd = &per_cpu(sibyte_hpt_clockevent, cpu);
 116         unsigned char *name = per_cpu(sibyte_hpt_name, cpu);
 117
 118         /* Only have 4 general purpose timers, and we use last one as hpt */
 119         BUG_ON(cpu > 2);
 120
 121         sprintf(name, "sb1250-counter-%d", cpu);
 122         cd->name                = name;
 123         cd->features            = CLOCK_EVT_FEAT_PERIODIC |
 124                                   CLOCK_EVT_FEAT_ONESHOT;
 125         clockevent_set_clock(cd, V_SCD_TIMER_FREQ);
 126         cd->max_delta_ns        = clockevent_delta2ns(0x7fffff, cd);
 127         cd->min_delta_ns        = clockevent_delta2ns(2, cd);
 128         cd->rating              = 200;
 129         cd->irq                 = irq;
 130         cd->cpumask             = cpumask_of(cpu);
 131         cd->set_next_event      = sibyte_next_event;
 132         cd->set_mode            = sibyte_set_mode;
 133         clockevents_register_device(cd);
 134
 135         sb1250_mask_irq(cpu, irq);
 136
 137         /*
 138          * Map the timer interrupt to IP[4] of this cpu
 139          */
 140         __raw_writeq(IMR_IP4_VAL,
 141                      IOADDR(A_IMR_REGISTER(cpu, R_IMR_INTERRUPT_MAP_BASE) +
 142                             (irq << 3)));
 143
 144         sb1250_unmask_irq(cpu, irq);
 145
 146         action->handler = sibyte_counter_handler;
 147         action->flags   = IRQF_PERCPU | IRQF_TIMER;
 148         action->name    = name;
 149         action->dev_id  = cd;
 150
 151         irq_set_affinity(irq, cpumask_of(cpu));
 152         setup_irq(irq, action);
 153 }