cpu/nios2/interrupts.c

   1 /*
   2  * (C) Copyright 2000-2002
   3  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
   4  *
   5  * (C) Copyright 2004, Psyent Corporation <www.psyent.com>
   6  * Scott McNutt <smcnutt@psyent.com>
   7  *
   8  * See file CREDITS for list of people who contributed to this
   9  * project.
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License as
  13  * published by the Free Software Foundation; either version 2 of
  14  * the License, or (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program; if not, write to the Free Software
  23  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  24  * MA 02111-1307 USA
  25  */
  26
  27
  28 #include <nios2.h>
  29 #include <nios2-io.h>
  30 #include <asm/ptrace.h>
  31 #include <common.h>
  32 #include <command.h>
  33 #include <watchdog.h>
  34 #ifdef CONFIG_STATUS_LED
  35 #include <status_led.h>
  36 #endif
  37
  38 #if defined(CFG_NIOS_TMRBASE) && !defined(CFG_NIOS_TMRIRQ)
  39 #error CFG_NIOS_TMRIRQ not defined (see documentation)
  40 #endif
  41
  42 /****************************************************************************/
  43
  44 struct  irq_action {
  45         interrupt_handler_t *handler;
  46         void *arg;
  47         int count;
  48 };
  49
  50 static struct irq_action vecs[32];
  51
  52 /*************************************************************************/
  53 volatile ulong timestamp = 0;
  54
  55 void reset_timer (void)
  56 {
  57         timestamp = 0;
  58 }
  59
  60 ulong get_timer (ulong base)
  61 {
  62         WATCHDOG_RESET ();
  63         return (timestamp - base);
  64 }
  65
  66 void set_timer (ulong t)
  67 {
  68         timestamp = t;
  69 }
  70
  71
  72 /* The board must handle this interrupt if a timer is not
  73  * provided.
  74  */
  75 #if defined(CFG_NIOS_TMRBASE)
  76 void tmr_isr (void *arg)
  77 {
  78         nios_timer_t *tmr = (nios_timer_t *)arg;
  79         /* Interrupt is cleared by writing anything to the
  80          * status register.
  81          */
  82         tmr->status = 0;
  83         timestamp += CFG_NIOS_TMRMS;
  84 #ifdef CONFIG_STATUS_LED
  85         status_led_tick(timestamp);
  86 #endif
  87 }
  88
  89 static void tmr_init (void)
  90 {
  91         nios_timer_t *tmr =(nios_timer_t *)CACHE_BYPASS(CFG_NIOS_TMRBASE);
  92
  93         tmr->control &= ~(NIOS_TIMER_START | NIOS_TIMER_ITO);
  94         tmr->control |= NIOS_TIMER_STOP;
  95 #if defined(CFG_NIOS_TMRCNT)
  96         tmr->periodl = CFG_NIOS_TMRCNT & 0xffff;
  97         tmr->periodh = (CFG_NIOS_TMRCNT >> 16) & 0xffff;
  98 #endif
  99         tmr->control |= ( NIOS_TIMER_ITO |
 100                           NIOS_TIMER_CONT |
 101                           NIOS_TIMER_START );
 102         irq_install_handler (CFG_NIOS_TMRIRQ, tmr_isr, (void *)tmr);
 103 }
 104
 105 #endif /* CFG_NIOS_TMRBASE */
 106
 107 /*************************************************************************/
 108 int disable_interrupts (void)
 109 {
 110         int val = rdctl (CTL_STATUS);
 111         wrctl (CTL_STATUS, val & ~STATUS_IE);
 112         return (val & STATUS_IE);
 113 }
 114
 115 void enable_interrupts( void )
 116 {
 117         int val = rdctl (CTL_STATUS);
 118         wrctl (CTL_STATUS, val | STATUS_IE);
 119 }
 120
 121 void external_interrupt (struct pt_regs *regs)
 122 {
 123         unsigned irqs;
 124         struct irq_action *act;
 125
 126         /* Evaluate only irqs that are both enabled AND pending */
 127         irqs = rdctl (CTL_IENABLE) & rdctl (CTL_IPENDING);
 128         act = vecs;
 129
 130         /* Assume (as does the Nios2 HAL) that bit 0 is highest
 131          * priority. NOTE: There is ALWAYS a handler assigned
 132          * (the default if no other).
 133          */
 134         while (irqs) {
 135                 if (irqs & 1) {
 136                         act->handler (act->arg);
 137                         act->count++;
 138                 }
 139                 irqs >>=1;
 140                 act++;
 141         }
 142 }
 143
 144 static void def_hdlr (void *arg)
 145 {
 146         unsigned irqs = rdctl (CTL_IENABLE);
 147
 148         /* Disable the individual interrupt -- with gratuitous
 149          * warning.
 150          */
 151         irqs &= ~(1 << (int)arg);
 152         wrctl (CTL_IENABLE, irqs);
 153         printf ("WARNING: Disabling unhandled interrupt: %d\n",
 154                         (int)arg);
 155 }
 156
 157 /*************************************************************************/
 158 void irq_install_handler (int irq, interrupt_handler_t *hdlr, void *arg)
 159 {
 160
 161         int flag;
 162         struct irq_action *act;
 163         unsigned ena = rdctl (CTL_IENABLE);
 164
 165         if ((irq < 0) || (irq > 31))
 166                 return;
 167         act = &vecs[irq];
 168
 169         flag = disable_interrupts ();
 170         if (hdlr) {
 171                 act->handler = hdlr;
 172                 act->arg = arg;
 173                 ena |= (1 << irq);              /* enable */
 174         } else {
 175                 act->handler = def_hdlr;
 176                 act->arg = (void *)irq;
 177                 ena &= ~(1 << irq);             /* disable */
 178         }
 179         wrctl (CTL_IENABLE, ena);
 180         if (flag) enable_interrupts ();
 181 }
 182
 183
 184 int interrupt_init (void)
 185 {
 186         int i;
 187
 188         /* Assign the default handler to all */
 189         for (i = 0; i < 32; i++) {
 190                 vecs[i].handler = def_hdlr;
 191                 vecs[i].arg = (void *)i;
 192                 vecs[i].count = 0;
 193         }
 194
 195 #if defined(CFG_NIOS_TMRBASE)
 196         tmr_init ();
 197 #endif
 198
 199         enable_interrupts ();
 200         return (0);
 201 }
 202
 203
 204 /*************************************************************************/
 205 #if (CONFIG_COMMANDS & CFG_CMD_IRQ)
 206 int do_irqinfo (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 207 {
 208         int i;
 209         struct irq_action *act = vecs;
 210
 211         printf ("\nInterrupt-Information:\n\n");
 212         printf ("Nr  Routine   Arg       Count\n");
 213         printf ("-----------------------------\n");
 214
 215         for (i=0; i<32; i++) {
 216                 if (act->handler != def_hdlr) {
 217                         printf ("%02d  %08lx  %08lx  %d\n",
 218                                 i,
 219                                 (ulong)act->handler,
 220                                 (ulong)act->arg,
 221                                 act->count);
 222                 }
 223                 act++;
 224         }
 225         printf ("\n");
 226
 227         return (0);
 228 }
 229 #endif  /* CONFIG_COMMANDS & CFG_CMD_IRQ */