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- /*
- * (C) Copyright 2002
- * John W. Linville <linville@tuxdriver.com>
- *
- * Copied and modified from original code by Josh Huber. Original
- * copyright notice preserved below.
- *
- * (C) Copyright 2001
- * Josh Huber <huber@mclx.com>, Mission Critical Linux, Inc.
- *
- * 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
- */
- /*
- * interrupts.c - just enough support for the decrementer/timer
- */
- #include <common.h>
- #include <asm/processor.h>
- #include <command.h>
- #include "i8259.h"
- #undef DEBUG
- #ifdef DEBUG
- #define PRINTF(fmt,args...) printf (fmt ,##args)
- #else
- #define PRINTF(fmt,args...)
- #endif
- #define NR_IRQS 16
- void irq_alloc_init(void);
- long irq_alloc(long wanted);
- /****************************************************************************/
- unsigned decrementer_count; /* count value for 1e6/HZ microseconds */
- struct irq_action {
- interrupt_handler_t *handler;
- void *arg;
- ulong count;
- };
- static struct irq_action irq_handlers[NR_IRQS];
- /****************************************************************************/
- static __inline__ unsigned long
- get_msr(void)
- {
- unsigned long msr;
- asm volatile("mfmsr %0" : "=r" (msr) :);
- return msr;
- }
- static __inline__ void
- set_msr(unsigned long msr)
- {
- asm volatile("mtmsr %0" : : "r" (msr));
- }
- static __inline__ unsigned long
- get_dec(void)
- {
- unsigned long val;
- asm volatile("mfdec %0" : "=r" (val) :);
- return val;
- }
- static __inline__ void
- set_dec(unsigned long val)
- {
- asm volatile("mtdec %0" : : "r" (val));
- }
- void
- enable_interrupts(void)
- {
- set_msr (get_msr() | MSR_EE);
- }
- /* returns flag if MSR_EE was set before */
- int
- disable_interrupts(void)
- {
- ulong msr;
- msr = get_msr();
- set_msr (msr & ~MSR_EE);
- return ((msr & MSR_EE) != 0);
- }
- /****************************************************************************/
- int interrupt_init (void)
- {
- extern void new_reset(void);
- extern void new_reset_end(void);
- #ifdef DEBUG
- puts("interrupt_init: setting decrementer_count\n");
- #endif
- decrementer_count = get_tbclk() / CONFIG_SYS_HZ;
- #ifdef DEBUG
- puts("interrupt_init: setting actual decremter\n");
- #endif
- set_dec (get_tbclk() / CONFIG_SYS_HZ);
- #ifdef DEBUG
- puts("interrupt_init: clearing external interrupt table\n");
- #endif
- /* clear external interrupt table here */
- memset(irq_handlers, 0, sizeof(irq_handlers));
- #ifdef DEBUG
- puts("interrupt_init: initializing interrupt controller\n");
- #endif
- i8259_init();
- #ifdef DEBUG
- puts("Copying reset trampoline\n");
- #endif
- /* WARNING: Assmues that the first megabyte is CACHEINHIBIT! */
- memcpy((void *)0x100, new_reset, new_reset_end - new_reset);
- #ifdef DEBUG
- PRINTF("interrupt_init: enabling interrupts (msr = %08x)\n",
- get_msr());
- #endif
- set_msr (get_msr() | MSR_EE);
- #ifdef DEBUG
- PRINTF("interrupt_init: done. (msr = %08x)\n", get_msr());
- #endif
- }
- /****************************************************************************/
- /*
- * Handle external interrupts
- */
- void
- external_interrupt(struct pt_regs *regs)
- {
- extern int i8259_irq(void);
- int irq, unmask = 1;
- irq = i8259_irq(); /*i8259_get_irq(regs); */
- /* printf("irq = %d, handler at %p ack=%d\n", irq, irq_handlers[irq].handler, *(volatile unsigned char *)0xFEF00000); */
- i8259_mask_and_ack(irq);
- if (irq_handlers[irq].handler != NULL)
- (*irq_handlers[irq].handler)(irq_handlers[irq].arg);
- else {
- PRINTF ("\nBogus External Interrupt IRQ %d\n", irq);
- /*
- * turn off the bogus interrupt, otherwise it
- * might repeat forever
- */
- unmask = 0;
- }
- if (unmask) i8259_unmask_irq(irq);
- }
- volatile ulong timestamp = 0;
- /*
- * timer_interrupt - gets called when the decrementer overflows,
- * with interrupts disabled.
- * Trivial implementation - no need to be really accurate.
- */
- void
- timer_interrupt(struct pt_regs *regs)
- {
- set_dec(decrementer_count);
- timestamp++;
- }
- /****************************************************************************/
- void
- reset_timer(void)
- {
- timestamp = 0;
- }
- ulong
- get_timer(ulong base)
- {
- return (timestamp - base);
- }
- void
- set_timer(ulong t)
- {
- timestamp = t;
- }
- /****************************************************************************/
- /*
- * Install and free a interrupt handler.
- */
- void
- irq_install_handler(int irq, interrupt_handler_t *handler, void *arg)
- {
- if (irq < 0 || irq >= NR_IRQS) {
- PRINTF("irq_install_handler: bad irq number %d\n", irq);
- return;
- }
- if (irq_handlers[irq].handler != NULL)
- PRINTF("irq_install_handler: 0x%08lx replacing 0x%08lx\n",
- (ulong)handler, (ulong)irq_handlers[irq].handler);
- irq_handlers[irq].handler = handler;
- irq_handlers[irq].arg = arg;
- i8259_unmask_irq(irq);
- }
- void
- irq_free_handler(int irq)
- {
- if (irq < 0 || irq >= NR_IRQS) {
- PRINTF("irq_free_handler: bad irq number %d\n", irq);
- return;
- }
- i8259_mask_irq(irq);
- irq_handlers[irq].handler = NULL;
- irq_handlers[irq].arg = NULL;
- }
- /****************************************************************************/
- void
- do_irqinfo(cmd_tbl_t *cmdtp, bd_t *bd, int flag, int argc, char *argv[])
- {
- puts("IRQ related functions are unimplemented currently.\n");
- }
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