arch/frv/kernel/irq-mb93091.c

   1 /* irq-mb93091.c: MB93091 FPGA interrupt handling
   2  *
   3  * Copyright (C) 2003 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/delay.h>
  24 #include <asm/irq.h>
  25 #include <asm/irc-regs.h>
  26
  27 #define __reg16(ADDR) (*(volatile unsigned short *)(ADDR))
  28
  29 #define __get_IMR()     ({ __reg16(0xffc00004); })
  30 #define __set_IMR(M)    do { __reg16(0xffc00004) = (M); wmb(); } while(0)
  31 #define __get_IFR()     ({ __reg16(0xffc0000c); })
  32 #define __clr_IFR(M)    do { __reg16(0xffc0000c) = ~(M); wmb(); } while(0)
  33
  34
  35 /*
  36  * on-motherboard FPGA PIC operations
  37  */
  38 static void frv_fpga_mask(struct irq_data *d)
  39 {
  40         uint16_t imr = __get_IMR();
  41
  42         imr |= 1 << (d->irq - IRQ_BASE_FPGA);
  43
  44         __set_IMR(imr);
  45 }
  46
  47 static void frv_fpga_ack(struct irq_data *d)
  48 {
  49         __clr_IFR(1 << (d->irq - IRQ_BASE_FPGA));
  50 }
  51
  52 static void frv_fpga_mask_ack(struct irq_data *d)
  53 {
  54         uint16_t imr = __get_IMR();
  55
  56         imr |= 1 << (d->irq - IRQ_BASE_FPGA);
  57         __set_IMR(imr);
  58
  59         __clr_IFR(1 << (d->irq - IRQ_BASE_FPGA));
  60 }
  61
  62 static void frv_fpga_unmask(struct irq_data *d)
  63 {
  64         uint16_t imr = __get_IMR();
  65
  66         imr &= ~(1 << (d->irq - IRQ_BASE_FPGA));
  67
  68         __set_IMR(imr);
  69 }
  70
  71 static struct irq_chip frv_fpga_pic = {
  72         .name           = "mb93091",
  73         .irq_ack        = frv_fpga_ack,
  74         .irq_mask       = frv_fpga_mask,
  75         .irq_mask_ack   = frv_fpga_mask_ack,
  76         .irq_unmask     = frv_fpga_unmask,
  77 };
  78
  79 /*
  80  * FPGA PIC interrupt handler
  81  */
  82 static 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_handle_irq(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  */
 107 static struct irqaction fpga_irq[4]  = {
 108         [0] = {
 109                 .handler        = fpga_interrupt,
 110                 .flags          = IRQF_SHARED,
 111                 .name           = "fpga.0",
 112                 .dev_id         = (void *) 0x0028UL,
 113         },
 114         [1] = {
 115                 .handler        = fpga_interrupt,
 116                 .flags          = IRQF_SHARED,
 117                 .name           = "fpga.1",
 118                 .dev_id         = (void *) 0x0050UL,
 119         },
 120         [2] = {
 121                 .handler        = fpga_interrupt,
 122                 .flags          = IRQF_SHARED,
 123                 .name           = "fpga.2",
 124                 .dev_id         = (void *) 0x1c00UL,
 125         },
 126         [3] = {
 127                 .handler        = fpga_interrupt,
 128                 .flags          = IRQF_SHARED,
 129                 .name           = "fpga.3",
 130                 .dev_id         = (void *) 0x6386UL,
 131         }
 132 };
 133
 134 /*
 135  * initialise the motherboard FPGA's PIC
 136  */
 137 void __init fpga_init(void)
 138 {
 139         int irq;
 140
 141         /* all PIC inputs are all set to be low-level driven, apart from the
 142          * NMI button (15) which is fixed at falling-edge
 143          */
 144         __set_IMR(0x7ffe);
 145         __clr_IFR(0x0000);
 146
 147         for (irq = IRQ_BASE_FPGA + 1; irq <= IRQ_BASE_FPGA + 14; irq++)
 148                 irq_set_chip_and_handler(irq, &frv_fpga_pic, handle_level_irq);
 149
 150         irq_set_chip_and_handler(IRQ_FPGA_NMI, &frv_fpga_pic, handle_edge_irq);
 151
 152         /* the FPGA drives the first four external IRQ inputs on the CPU PIC */
 153         setup_irq(IRQ_CPU_EXTERNAL0, &fpga_irq[0]);
 154         setup_irq(IRQ_CPU_EXTERNAL1, &fpga_irq[1]);
 155         setup_irq(IRQ_CPU_EXTERNAL2, &fpga_irq[2]);
 156         setup_irq(IRQ_CPU_EXTERNAL3, &fpga_irq[3]);
 157 }