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