LXR linux/arch/frv/kernel/irq-mb93093.c

   1/* irq-mb93093.c: MB93093 FPGA interrupt handling
   2 *
   3 * Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
   4 * Written by David Howells (dhowells@redhat.com)
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version
   9 * 2 of the License, or (at your option) any later version.
  10 */
  11
  12#include <linux/ptrace.h>
  13#include <linux/errno.h>
  14#include <linux/signal.h>
  15#include <linux/sched.h>
  16#include <linux/ioport.h>
  17#include <linux/interrupt.h>
  18#include <linux/init.h>
  19#include <linux/irq.h>
  20#include <linux/bitops.h>
  21
  22#include <asm/io.h>
  23#include <asm/system.h>
  24#include <asm/delay.h>
  25#include <asm/irq.h>
  26#include <asm/irc-regs.h>
  27
  28#define __reg16(ADDR) (*(volatile unsigned short *)(__region_CS2 + (ADDR)))
  29
  30#define __get_IMR()     ({ __reg16(0x0a); })
  31#define __set_IMR(M)    do { __reg16(0x0a) = (M);  wmb(); } while(0)
  32#define __get_IFR()     ({ __reg16(0x02); })
  33#define __clr_IFR(M)    do { __reg16(0x02) = ~(M); wmb(); } while(0)
  34
  35/*
  36 * off-CPU FPGA PIC operations
  37 */
  38static void frv_fpga_mask(unsigned int irq)
  39{
  40        uint16_t imr = __get_IMR();
  41
  42        imr |= 1 << (irq - IRQ_BASE_FPGA);
  43        __set_IMR(imr);
  44}
  45
  46static void frv_fpga_ack(unsigned int irq)
  47{
  48        __clr_IFR(1 << (irq - IRQ_BASE_FPGA));
  49}
  50
  51static void frv_fpga_mask_ack(unsigned int irq)
  52{
  53        uint16_t imr = __get_IMR();
  54
  55        imr |= 1 << (irq - IRQ_BASE_FPGA);
  56        __set_IMR(imr);
  57
  58        __clr_IFR(1 << (irq - IRQ_BASE_FPGA));
  59}
  60
  61static void frv_fpga_unmask(unsigned int irq)
  62{
  63        uint16_t imr = __get_IMR();
  64
  65        imr &= ~(1 << (irq - IRQ_BASE_FPGA));
  66
  67        __set_IMR(imr);
  68}
  69
  70static struct irq_chip frv_fpga_pic = {
  71        .name           = "mb93093",
  72        .ack            = frv_fpga_ack,
  73        .mask           = frv_fpga_mask,
  74        .mask_ack       = frv_fpga_mask_ack,
  75        .unmask         = frv_fpga_unmask,
  76        .end            = frv_fpga_end,
  77};
  78
  79/*
  80 * FPGA PIC interrupt handler
  81 */
  82static irqreturn_t fpga_interrupt(int irq, void *_mask)
  83{
  84        uint16_t imr, mask = (unsigned long) _mask;
  85
  86        imr = __get_IMR();
  87        mask = mask & ~imr & __get_IFR();
  88
  89        /* poll all the triggered IRQs */
  90        while (mask) {
  91                int irq;
  92
  93                asm("scan %1,gr0,%0" : "=r"(irq) : "r"(mask));
  94                irq = 31 - irq;
  95                mask &= ~(1 << irq);
  96
  97                generic_irq_handle(IRQ_BASE_FPGA + irq);
  98        }
  99
 100        return IRQ_HANDLED;
 101}
 102
 103/*
 104 * define an interrupt action for each FPGA PIC output
 105 * - use dev_id to indicate the FPGA PIC input to output mappings
 106 */
 107static struct irqaction fpga_irq[1]  = {
 108        [0] = {
 109                .handler        = fpga_interrupt,
 110                .flags          = IRQF_DISABLED,
 111                .name           = "fpga.0",
 112                .dev_id         = (void *) 0x0700UL,
 113        }
 114};
 115
 116/*
 117 * initialise the motherboard FPGA's PIC
 118 */
 119void __init fpga_init(void)
 120{
 121        int irq;
 122
 123        /* all PIC inputs are all set to be edge triggered */
 124        __set_IMR(0x0700);
 125        __clr_IFR(0x0000);
 126
 127        for (irq = IRQ_BASE_FPGA + 8; irq <= IRQ_BASE_FPGA + 10; irq++)
 128                set_irq_chip_and_handler(irq, &frv_fpga_pic, handle_edge_irq);
 129
 130        /* the FPGA drives external IRQ input #2 on the CPU PIC */
 131        setup_irq(IRQ_CPU_EXTERNAL2, &fpga_irq[0]);
 132}
 133