arch/nios2/cpu/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/types.h>
  31 #include <asm/io.h>
  32 #include <asm/ptrace.h>
  33 #include <common.h>
  34 #include <command.h>
  35 #include <watchdog.h>
  36 #ifdef CONFIG_STATUS_LED
  37 #include <status_led.h>
  38 #endif
  39
  40 #if defined(CONFIG_SYS_NIOS_TMRBASE) && !defined(CONFIG_SYS_NIOS_TMRIRQ)
  41 #error CONFIG_SYS_NIOS_TMRIRQ not defined (see documentation)
  42 #endif
  43
  44 /****************************************************************************/
  45
  46 struct  irq_action {
  47         interrupt_handler_t *handler;
  48         void *arg;
  49         int count;
  50 };
  51
  52 static struct irq_action vecs[32];
  53
  54 /*************************************************************************/
  55 volatile ulong timestamp = 0;
  56
  57 void reset_timer (void)
  58 {
  59         nios_timer_t *tmr =(nios_timer_t *)CONFIG_SYS_NIOS_TMRBASE;
  60
  61         /* From Embedded Peripherals Handbook:
  62          *
  63          * "When the hardware is configured with Writeable period
  64          * disabled, writing to one of the period_n registers causes
  65          * the counter to reset to the fixed Timeout Period specified
  66          * at system generation time."
  67          *
  68          * Here we force a reload to prevent early timeouts from
  69          * get_timer() when the interrupt period is greater than
  70          * than 1 msec.
  71          *
  72          * Simply write to periodl with its own value to force an
  73          * internal counter reload, THEN reset the timestamp.
  74          */
  75         writel (readl (&tmr->periodl), &tmr->periodl);
  76         timestamp = 0;
  77
  78         /* From Embedded Peripherals Handbook:
  79          *
  80          * "Writing to one of the period_n registers stops the internal
  81          * counter, except when the hardware is configured with Start/Stop
  82          * control bits off. If Start/Stop control bits is off, writing
  83          * either register does not stop the counter."
  84          *
  85          * In order to accomodate either configuration, the control
  86          * register is re-written. If the counter is stopped, it will
  87          * be restarted. If it is running, the write is essentially
  88          * a nop.
  89          */
  90         writel (NIOS_TIMER_ITO | NIOS_TIMER_CONT | NIOS_TIMER_START,
  91                         &tmr->control);
  92
  93 }
  94
  95 ulong get_timer (ulong base)
  96 {
  97         WATCHDOG_RESET ();
  98         return (timestamp - base);
  99 }
 100
 101 void set_timer (ulong t)
 102 {
 103         timestamp = t;
 104 }
 105
 106
 107 /* The board must handle this interrupt if a timer is not
 108  * provided.
 109  */
 110 #if defined(CONFIG_SYS_NIOS_TMRBASE)
 111 void tmr_isr (void *arg)
 112 {
 113         nios_timer_t *tmr = (nios_timer_t *)arg;
 114         /* Interrupt is cleared by writing anything to the
 115          * status register.
 116          */
 117         writel (0, &tmr->status);
 118         timestamp += CONFIG_SYS_NIOS_TMRMS;
 119 #ifdef CONFIG_STATUS_LED
 120         status_led_tick(timestamp);
 121 #endif
 122 }
 123
 124 static void tmr_init (void)
 125 {
 126         nios_timer_t *tmr =(nios_timer_t *)CONFIG_SYS_NIOS_TMRBASE;
 127
 128         writel (0, &tmr->status);
 129         writel (0, &tmr->control);
 130         writel (NIOS_TIMER_STOP, &tmr->control);
 131
 132 #if defined(CONFIG_SYS_NIOS_TMRCNT)
 133         writel (CONFIG_SYS_NIOS_TMRCNT & 0xffff, &tmr->periodl);
 134         writel ((CONFIG_SYS_NIOS_TMRCNT >> 16) & 0xffff, &tmr->periodh);
 135 #endif
 136         writel (NIOS_TIMER_ITO | NIOS_TIMER_CONT | NIOS_TIMER_START,
 137                         &tmr->control);
 138         irq_install_handler (CONFIG_SYS_NIOS_TMRIRQ, tmr_isr, (void *)tmr);
 139 }
 140
 141 #endif /* CONFIG_SYS_NIOS_TMRBASE */
 142
 143 /*************************************************************************/
 144 int disable_interrupts (void)
 145 {
 146         int val = rdctl (CTL_STATUS);
 147         wrctl (CTL_STATUS, val & ~STATUS_IE);
 148         return (val & STATUS_IE);
 149 }
 150
 151 void enable_interrupts( void )
 152 {
 153         int val = rdctl (CTL_STATUS);
 154         wrctl (CTL_STATUS, val | STATUS_IE);
 155 }
 156
 157 void external_interrupt (struct pt_regs *regs)
 158 {
 159         unsigned irqs;
 160         struct irq_action *act;
 161
 162         /* Evaluate only irqs that are both enabled AND pending */
 163         irqs = rdctl (CTL_IENABLE) & rdctl (CTL_IPENDING);
 164         act = vecs;
 165
 166         /* Assume (as does the Nios2 HAL) that bit 0 is highest
 167          * priority. NOTE: There is ALWAYS a handler assigned
 168          * (the default if no other).
 169          */
 170         while (irqs) {
 171                 if (irqs & 1) {
 172                         act->handler (act->arg);
 173                         act->count++;
 174                 }
 175                 irqs >>=1;
 176                 act++;
 177         }
 178 }
 179
 180 static void def_hdlr (void *arg)
 181 {
 182         unsigned irqs = rdctl (CTL_IENABLE);
 183
 184         /* Disable the individual interrupt -- with gratuitous
 185          * warning.
 186          */
 187         irqs &= ~(1 << (int)arg);
 188         wrctl (CTL_IENABLE, irqs);
 189         printf ("WARNING: Disabling unhandled interrupt: %d\n",
 190                         (int)arg);
 191 }
 192
 193 /*************************************************************************/
 194 void irq_install_handler (int irq, interrupt_handler_t *hdlr, void *arg)
 195 {
 196
 197         int flag;
 198         struct irq_action *act;
 199         unsigned ena = rdctl (CTL_IENABLE);
 200
 201         if ((irq < 0) || (irq > 31))
 202                 return;
 203         act = &vecs[irq];
 204
 205         flag = disable_interrupts ();
 206         if (hdlr) {
 207                 act->handler = hdlr;
 208                 act->arg = arg;
 209                 ena |= (1 << irq);              /* enable */
 210         } else {
 211                 act->handler = def_hdlr;
 212                 act->arg = (void *)irq;
 213                 ena &= ~(1 << irq);             /* disable */
 214         }
 215         wrctl (CTL_IENABLE, ena);
 216         if (flag) enable_interrupts ();
 217 }
 218
 219
 220 int interrupt_init (void)
 221 {
 222         int i;
 223
 224         /* Assign the default handler to all */
 225         for (i = 0; i < 32; i++) {
 226                 vecs[i].handler = def_hdlr;
 227                 vecs[i].arg = (void *)i;
 228                 vecs[i].count = 0;
 229         }
 230
 231 #if defined(CONFIG_SYS_NIOS_TMRBASE)
 232         tmr_init ();
 233 #endif
 234
 235         enable_interrupts ();
 236         return (0);
 237 }
 238
 239
 240 /*************************************************************************/
 241 #if defined(CONFIG_CMD_IRQ)
 242 int do_irqinfo (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 243 {
 244         int i;
 245         struct irq_action *act = vecs;
 246
 247         printf ("\nInterrupt-Information:\n\n");
 248         printf ("Nr  Routine   Arg       Count\n");
 249         printf ("-----------------------------\n");
 250
 251         for (i=0; i<32; i++) {
 252                 if (act->handler != def_hdlr) {
 253                         printf ("%02d  %08lx  %08lx  %d\n",
 254                                 i,
 255                                 (ulong)act->handler,
 256                                 (ulong)act->arg,
 257                                 act->count);
 258                 }
 259                 act++;
 260         }
 261         printf ("\n");
 262
 263         return (0);
 264 }
 265 #endif