1 files changed, 265 insertions, 0 deletions
diff --git a/arch/nios2/cpu/interrupts.c b/arch/nios2/cpu/interrupts.c
new file mode 100644
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--- /dev/null
+++ b/arch/nios2/cpu/interrupts.c
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+/*
+ * (C) Copyright 2000-2002
+ * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+ *
+ * (C) Copyright 2004, Psyent Corporation <www.psyent.com>
+ * Scott McNutt <smcnutt@psyent.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+
+#include <nios2.h>
+#include <nios2-io.h>
+#include <asm/types.h>
+#include <asm/io.h>
+#include <asm/ptrace.h>
+#include <common.h>
+#include <command.h>
+#include <watchdog.h>
+#ifdef CONFIG_STATUS_LED
+#include <status_led.h>
+#endif
+
+#if defined(CONFIG_SYS_NIOS_TMRBASE) && !defined(CONFIG_SYS_NIOS_TMRIRQ)
+#error CONFIG_SYS_NIOS_TMRIRQ not defined (see documentation)
+#endif
+
+/****************************************************************************/
+
+struct	irq_action {
+	interrupt_handler_t *handler;
+	void *arg;
+	int count;
+};
+
+static struct irq_action vecs[32];
+
+/*************************************************************************/
+volatile ulong timestamp = 0;
+
+void reset_timer (void)
+{
+	nios_timer_t *tmr =(nios_timer_t *)CONFIG_SYS_NIOS_TMRBASE;
+
+	/* From Embedded Peripherals Handbook:
+	 *
+	 * "When the hardware is configured with Writeable period
+	 * disabled, writing to one of the period_n registers causes
+	 * the counter to reset to the fixed Timeout Period specified
+	 * at system generation time."
+	 *
+	 * Here we force a reload to prevent early timeouts from
+	 * get_timer() when the interrupt period is greater than
+	 * than 1 msec.
+	 *
+	 * Simply write to periodl with its own value to force an
+	 * internal counter reload, THEN reset the timestamp.
+	 */
+	writel (readl (&tmr->periodl), &tmr->periodl);
+	timestamp = 0;
+
+	/* From Embedded Peripherals Handbook:
+	 *
+	 * "Writing to one of the period_n registers stops the internal
+	 * counter, except when the hardware is configured with Start/Stop
+	 * control bits off. If Start/Stop control bits is off, writing
+	 * either register does not stop the counter."
+	 *
+	 * In order to accomodate either configuration, the control
+	 * register is re-written. If the counter is stopped, it will
+	 * be restarted. If it is running, the write is essentially
+	 * a nop.
+	 */
+	writel (NIOS_TIMER_ITO | NIOS_TIMER_CONT | NIOS_TIMER_START,
+			&tmr->control);
+
+}
+
+ulong get_timer (ulong base)
+{
+	WATCHDOG_RESET ();
+	return (timestamp - base);
+}
+
+void set_timer (ulong t)
+{
+	timestamp = t;
+}
+
+
+/* The board must handle this interrupt if a timer is not
+ * provided.
+ */
+#if defined(CONFIG_SYS_NIOS_TMRBASE)
+void tmr_isr (void *arg)
+{
+	nios_timer_t *tmr = (nios_timer_t *)arg;
+	/* Interrupt is cleared by writing anything to the
+	 * status register.
+	 */
+	writel (0, &tmr->status);
+	timestamp += CONFIG_SYS_NIOS_TMRMS;
+#ifdef CONFIG_STATUS_LED
+	status_led_tick(timestamp);
+#endif
+}
+
+static void tmr_init (void)
+{
+	nios_timer_t *tmr =(nios_timer_t *)CONFIG_SYS_NIOS_TMRBASE;
+
+	writel (0, &tmr->status);
+	writel (0, &tmr->control);
+	writel (NIOS_TIMER_STOP, &tmr->control);
+
+#if defined(CONFIG_SYS_NIOS_TMRCNT)
+	writel (CONFIG_SYS_NIOS_TMRCNT & 0xffff, &tmr->periodl);
+	writel ((CONFIG_SYS_NIOS_TMRCNT >> 16) & 0xffff, &tmr->periodh);
+#endif
+	writel (NIOS_TIMER_ITO | NIOS_TIMER_CONT | NIOS_TIMER_START,
+			&tmr->control);
+	irq_install_handler (CONFIG_SYS_NIOS_TMRIRQ, tmr_isr, (void *)tmr);
+}
+
+#endif /* CONFIG_SYS_NIOS_TMRBASE */
+
+/*************************************************************************/
+int disable_interrupts (void)
+{
+	int val = rdctl (CTL_STATUS);
+	wrctl (CTL_STATUS, val & ~STATUS_IE);
+	return (val & STATUS_IE);
+}
+
+void enable_interrupts( void )
+{
+	int val = rdctl (CTL_STATUS);
+	wrctl (CTL_STATUS, val | STATUS_IE);
+}
+
+void external_interrupt (struct pt_regs *regs)
+{
+	unsigned irqs;
+	struct irq_action *act;
+
+	/* Evaluate only irqs that are both enabled AND pending */
+	irqs = rdctl (CTL_IENABLE) & rdctl (CTL_IPENDING);
+	act = vecs;
+
+	/* Assume (as does the Nios2 HAL) that bit 0 is highest
+	 * priority. NOTE: There is ALWAYS a handler assigned
+	 * (the default if no other).
+	 */
+	while (irqs) {
+		if (irqs & 1) {
+			act->handler (act->arg);
+			act->count++;
+		}
+		irqs >>=1;
+		act++;
+	}
+}
+
+static void def_hdlr (void *arg)
+{
+	unsigned irqs = rdctl (CTL_IENABLE);
+
+	/* Disable the individual interrupt -- with gratuitous
+	 * warning.
+	 */
+	irqs &= ~(1 << (int)arg);
+	wrctl (CTL_IENABLE, irqs);
+	printf ("WARNING: Disabling unhandled interrupt: %d\n",
+			(int)arg);
+}
+
+/*************************************************************************/
+void irq_install_handler (int irq, interrupt_handler_t *hdlr, void *arg)
+{
+
+	int flag;
+	struct irq_action *act;
+	unsigned ena = rdctl (CTL_IENABLE);
+
+	if ((irq < 0) || (irq > 31))
+		return;
+	act = &vecs[irq];
+
+	flag = disable_interrupts ();
+	if (hdlr) {
+		act->handler = hdlr;
+		act->arg = arg;
+		ena |= (1 << irq);		/* enable */
+	} else {
+		act->handler = def_hdlr;
+		act->arg = (void *)irq;
+		ena &= ~(1 << irq);		/* disable */
+	}
+	wrctl (CTL_IENABLE, ena);
+	if (flag) enable_interrupts ();
+}
+
+
+int interrupt_init (void)
+{
+	int i;
+
+	/* Assign the default handler to all */
+	for (i = 0; i < 32; i++) {
+		vecs[i].handler = def_hdlr;
+		vecs[i].arg = (void *)i;
+		vecs[i].count = 0;
+	}
+
+#if defined(CONFIG_SYS_NIOS_TMRBASE)
+	tmr_init ();
+#endif
+
+	enable_interrupts ();
+	return (0);
+}
+
+
+/*************************************************************************/
+#if defined(CONFIG_CMD_IRQ)
+int do_irqinfo (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+	int i;
+	struct irq_action *act = vecs;
+
+	printf ("\nInterrupt-Information:\n\n");
+	printf ("Nr  Routine   Arg       Count\n");
+	printf ("-----------------------------\n");
+
+	for (i=0; i<32; i++) {
+		if (act->handler != def_hdlr) {
+			printf ("%02d  %08lx  %08lx  %d\n",
+				i,
+				(ulong)act->handler,
+				(ulong)act->arg,
+				act->count);
+		}
+		act++;
+	}
+	printf ("\n");
+
+	return (0);
+}
+#endif