board/MAI/AmigaOneG3SE/interrupts.c

   1 /*
   2  * (C) Copyright 2002
   3  * John W. Linville <linville@tuxdriver.com>
   4  *
   5  *    Copied and modified from original code by Josh Huber.  Original
   6  *    copyright notice preserved below.
   7  *
   8  * (C) Copyright 2001
   9  * Josh Huber <huber@mclx.com>, Mission Critical Linux, Inc.
  10  *
  11  * See file CREDITS for list of people who contributed to this
  12  * project.
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License as
  16  * published by the Free Software Foundation; either version 2 of
  17  * the License, or (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  27  * MA 02111-1307 USA
  28  */
  29
  30 /*
  31  * interrupts.c - just enough support for the decrementer/timer
  32  */
  33
  34 #include <common.h>
  35 #include <asm/processor.h>
  36 #include <command.h>
  37 #include "i8259.h"
  38
  39 #undef DEBUG
  40 #ifdef  DEBUG
  41 #define PRINTF(fmt,args...)     printf (fmt ,##args)
  42 #else
  43 #define PRINTF(fmt,args...)
  44 #endif
  45 #define NR_IRQS 16
  46
  47 void irq_alloc_init(void);
  48 long irq_alloc(long wanted);
  49
  50 /****************************************************************************/
  51
  52 unsigned decrementer_count;          /* count value for 1e6/HZ microseconds */
  53
  54 struct irq_action {
  55     interrupt_handler_t *handler;
  56     void *arg;
  57     ulong count;
  58 };
  59
  60 static struct irq_action irq_handlers[NR_IRQS];
  61
  62 /****************************************************************************/
  63
  64 static __inline__ unsigned long
  65 get_msr(void)
  66 {
  67         unsigned long msr;
  68
  69         asm volatile("mfmsr %0" : "=r" (msr) :);
  70         return msr;
  71 }
  72
  73 static __inline__ void
  74 set_msr(unsigned long msr)
  75 {
  76         asm volatile("mtmsr %0" : : "r" (msr));
  77 }
  78
  79 static __inline__ unsigned long
  80 get_dec(void)
  81 {
  82         unsigned long val;
  83
  84         asm volatile("mfdec %0" : "=r" (val) :);
  85         return val;
  86 }
  87
  88
  89 static __inline__ void
  90 set_dec(unsigned long val)
  91 {
  92         asm volatile("mtdec %0" : : "r" (val));
  93 }
  94
  95
  96 void
  97 enable_interrupts(void)
  98 {
  99     set_msr (get_msr() | MSR_EE);
 100 }
 101
 102 /* returns flag if MSR_EE was set before */
 103 int
 104 disable_interrupts(void)
 105 {
 106     ulong msr;
 107
 108     msr = get_msr();
 109     set_msr (msr & ~MSR_EE);
 110     return ((msr & MSR_EE) != 0);
 111 }
 112
 113 /****************************************************************************/
 114
 115 int interrupt_init (void)
 116 {
 117     extern void new_reset(void);
 118     extern void new_reset_end(void);
 119 #ifdef DEBUG
 120         puts("interrupt_init: setting decrementer_count\n");
 121 #endif
 122         decrementer_count = get_tbclk() / CONFIG_SYS_HZ;
 123
 124 #ifdef DEBUG
 125         puts("interrupt_init: setting actual decremter\n");
 126 #endif
 127         set_dec (get_tbclk() / CONFIG_SYS_HZ);
 128
 129 #ifdef DEBUG
 130         puts("interrupt_init: clearing external interrupt table\n");
 131 #endif
 132         /* clear external interrupt table here */
 133         memset(irq_handlers, 0, sizeof(irq_handlers));
 134
 135 #ifdef DEBUG
 136         puts("interrupt_init: initializing interrupt controller\n");
 137 #endif
 138         i8259_init();
 139
 140 #ifdef DEBUG
 141         puts("Copying reset trampoline\n");
 142 #endif
 143         /* WARNING: Assmues that the first megabyte is CACHEINHIBIT! */
 144         memcpy((void *)0x100, new_reset, new_reset_end - new_reset);
 145
 146 #ifdef DEBUG
 147         PRINTF("interrupt_init: enabling interrupts (msr = %08x)\n",
 148                 get_msr());
 149 #endif
 150         set_msr (get_msr() | MSR_EE);
 151
 152 #ifdef DEBUG
 153         PRINTF("interrupt_init: done. (msr = %08x)\n", get_msr());
 154 #endif
 155
 156 }
 157
 158 /****************************************************************************/
 159
 160 /*
 161  * Handle external interrupts
 162  */
 163 void
 164 external_interrupt(struct pt_regs *regs)
 165 {
 166     extern int i8259_irq(void);
 167
 168         int irq, unmask = 1;
 169
 170         irq = i8259_irq(); /*i8259_get_irq(regs); */
 171 /*      printf("irq = %d, handler at %p ack=%d\n", irq, irq_handlers[irq].handler, *(volatile unsigned char *)0xFEF00000); */
 172         i8259_mask_and_ack(irq);
 173
 174         if (irq_handlers[irq].handler != NULL)
 175                 (*irq_handlers[irq].handler)(irq_handlers[irq].arg);
 176         else {
 177                 PRINTF ("\nBogus External Interrupt IRQ %d\n", irq);
 178                 /*
 179                 * turn off the bogus interrupt, otherwise it
 180                 * might repeat forever
 181                 */
 182                 unmask = 0;
 183         }
 184
 185         if (unmask) i8259_unmask_irq(irq);
 186 }
 187
 188 volatile ulong timestamp = 0;
 189
 190 /*
 191  * timer_interrupt - gets called when the decrementer overflows,
 192  * with interrupts disabled.
 193  * Trivial implementation - no need to be really accurate.
 194  */
 195 void
 196 timer_interrupt(struct pt_regs *regs)
 197 {
 198         set_dec(decrementer_count);
 199         timestamp++;
 200 }
 201
 202 /****************************************************************************/
 203
 204 void
 205 reset_timer(void)
 206 {
 207         timestamp = 0;
 208 }
 209
 210 ulong
 211 get_timer(ulong base)
 212 {
 213         return (timestamp - base);
 214 }
 215
 216 void
 217 set_timer(ulong t)
 218 {
 219         timestamp = t;
 220 }
 221
 222 /****************************************************************************/
 223
 224 /*
 225  * Install and free a interrupt handler.
 226  */
 227
 228 void
 229 irq_install_handler(int irq, interrupt_handler_t *handler, void *arg)
 230 {
 231         if (irq < 0 || irq >= NR_IRQS) {
 232                 PRINTF("irq_install_handler: bad irq number %d\n", irq);
 233                 return;
 234         }
 235
 236         if (irq_handlers[irq].handler != NULL)
 237                 PRINTF("irq_install_handler: 0x%08lx replacing 0x%08lx\n",
 238                        (ulong)handler, (ulong)irq_handlers[irq].handler);
 239
 240         irq_handlers[irq].handler = handler;
 241         irq_handlers[irq].arg     = arg;
 242
 243         i8259_unmask_irq(irq);
 244 }
 245
 246 void
 247 irq_free_handler(int irq)
 248 {
 249         if (irq < 0 || irq >= NR_IRQS) {
 250                 PRINTF("irq_free_handler: bad irq number %d\n", irq);
 251                 return;
 252         }
 253
 254         i8259_mask_irq(irq);
 255
 256         irq_handlers[irq].handler = NULL;
 257         irq_handlers[irq].arg     = NULL;
 258 }
 259
 260 /****************************************************************************/
 261
 262 void
 263 do_irqinfo(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[])
 264 {
 265         puts("IRQ related functions are unimplemented currently.\n");
 266 }