arch/arm/mach-aaec2000/core.c

   1 /*
   2  *  linux/arch/arm/mach-aaec2000/core.c
   3  *
   4  *  Code common to all AAEC-2000 machines
   5  *
   6  *  Copyright (c) 2005 Nicolas Bellido Y Ortega
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License version 2 as
  10  *  published by the Free Software Foundation.
  11  */
  12 #include <linux/config.h>
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/list.h>
  17 #include <linux/errno.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/timex.h>
  20 #include <linux/signal.h>
  21
  22 #include <asm/hardware.h>
  23 #include <asm/irq.h>
  24
  25 #include <asm/mach/irq.h>
  26 #include <asm/mach/time.h>
  27 #include <asm/mach/map.h>
  28
  29 /*
  30  * Common I/O mapping:
  31  *
  32  * Static virtual address mappings are as follow:
  33  *
  34  * 0xf8000000-0xf8001ffff: Devices connected to APB bus
  35  * 0xf8002000-0xf8003ffff: Devices connected to AHB bus
  36  *
  37  * Below 0xe8000000 is reserved for vm allocation.
  38  *
  39  * The machine specific code must provide the extra mapping beside the
  40  * default mapping provided here.
  41  */
  42 static struct map_desc standard_io_desc[] __initdata = {
  43  /* virtual         physical       length           type */
  44   { VIO_APB_BASE,   PIO_APB_BASE,  IO_APB_LENGTH,   MT_DEVICE },
  45   { VIO_AHB_BASE,   PIO_AHB_BASE,  IO_AHB_LENGTH,   MT_DEVICE }
  46 };
  47
  48 void __init aaec2000_map_io(void)
  49 {
  50         iotable_init(standard_io_desc, ARRAY_SIZE(standard_io_desc));
  51 }
  52
  53 /*
  54  * Interrupt handling routines
  55  */
  56 static void aaec2000_int_ack(unsigned int irq)
  57 {
  58         IRQ_INTSR = 1 << irq;
  59 }
  60
  61 static void aaec2000_int_mask(unsigned int irq)
  62 {
  63         IRQ_INTENC |= (1 << irq);
  64 }
  65
  66 static void aaec2000_int_unmask(unsigned int irq)
  67 {
  68         IRQ_INTENS |= (1 << irq);
  69 }
  70
  71 static struct irqchip aaec2000_irq_chip = {
  72         .ack    = aaec2000_int_ack,
  73         .mask   = aaec2000_int_mask,
  74         .unmask = aaec2000_int_unmask,
  75 };
  76
  77 void __init aaec2000_init_irq(void)
  78 {
  79         unsigned int i;
  80
  81         for (i = 0; i < NR_IRQS; i++) {
  82                 set_irq_handler(i, do_level_IRQ);
  83                 set_irq_chip(i, &aaec2000_irq_chip);
  84                 set_irq_flags(i, IRQF_VALID);
  85         }
  86
  87         /* Disable all interrupts */
  88         IRQ_INTENC = 0xffffffff;
  89
  90         /* Clear any pending interrupts */
  91         IRQ_INTSR = IRQ_INTSR;
  92 }
  93
  94 /*
  95  * Time keeping
  96  */
  97 /* IRQs are disabled before entering here from do_gettimeofday() */
  98 static unsigned long aaec2000_gettimeoffset(void)
  99 {
 100         unsigned long ticks_to_match, elapsed, usec;
 101
 102         /* Get ticks before next timer match */
 103         ticks_to_match = TIMER1_LOAD - TIMER1_VAL;
 104
 105         /* We need elapsed ticks since last match */
 106         elapsed = LATCH - ticks_to_match;
 107
 108         /* Now, convert them to usec */
 109         usec = (unsigned long)(elapsed * (tick_nsec / 1000))/LATCH;
 110
 111         return usec;
 112 }
 113
 114 /* We enter here with IRQs enabled */
 115 static irqreturn_t
 116 aaec2000_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 117 {
 118         /* TODO: Check timer accuracy */
 119         write_seqlock(&xtime_lock);
 120
 121         timer_tick(regs);
 122         TIMER1_CLEAR = 1;
 123
 124         write_sequnlock(&xtime_lock);
 125
 126         return IRQ_HANDLED;
 127 }
 128
 129 static struct irqaction aaec2000_timer_irq = {
 130         .name           = "AAEC-2000 Timer Tick",
 131         .flags          = SA_INTERRUPT | SA_TIMER,
 132         .handler        = aaec2000_timer_interrupt,
 133 };
 134
 135 static void __init aaec2000_timer_init(void)
 136 {
 137         /* Disable timer 1 */
 138         TIMER1_CTRL = 0;
 139
 140         /* We have somehow to generate a 100Hz clock.
 141          * We then use the 508KHz timer in periodic mode.
 142          */
 143         TIMER1_LOAD = LATCH;
 144         TIMER1_CLEAR = 1; /* Clear interrupt */
 145
 146         setup_irq(INT_TMR1_OFL, &aaec2000_timer_irq);
 147
 148         TIMER1_CTRL = TIMER_CTRL_ENABLE |
 149                         TIMER_CTRL_PERIODIC |
 150                         TIMER_CTRL_CLKSEL_508K;
 151 }
 152
 153 struct sys_timer aaec2000_timer = {
 154         .init           = aaec2000_timer_init,
 155         .offset         = aaec2000_gettimeoffset,
 156 };
 157