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
  21 #include <asm/io.h>
  22 #include <asm/system.h>
  23 #include <asm/bitops.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 *)(ADDR))
  29
  30 #define __get_IMR()     ({ __reg16(0xffc00004); })
  31 #define __set_IMR(M)    do { __reg16(0xffc00004) = (M); wmb(); } while(0)
  32 #define __get_IFR()     ({ __reg16(0xffc0000c); })
  33 #define __clr_IFR(M)    do { __reg16(0xffc0000c) = ~(M); wmb(); } while(0)
  34
  35
  36 /*
  37  * on-motherboard FPGA PIC operations
  38  */
  39 static void frv_fpga_mask(unsigned int irq)
  40 {
  41         uint16_t imr = __get_IMR();
  42
  43         imr |= 1 << (irq - IRQ_BASE_FPGA);
  44
  45         __set_IMR(imr);
  46 }
  47
  48 static void frv_fpga_ack(unsigned int irq)
  49 {
  50         __clr_IFR(1 << (irq - IRQ_BASE_FPGA));
  51 }
  52
  53 static void frv_fpga_mask_ack(unsigned int irq)
  54 {
  55         uint16_t imr = __get_IMR();
  56
  57         imr |= 1 << (irq - IRQ_BASE_FPGA);
  58         __set_IMR(imr);
  59
  60         __clr_IFR(1 << (irq - IRQ_BASE_FPGA));
  61 }
  62
  63 static void frv_fpga_unmask(unsigned int irq)
  64 {
  65         uint16_t imr = __get_IMR();
  66
  67         imr &= ~(1 << (irq - IRQ_BASE_FPGA));
  68
  69         __set_IMR(imr);
  70 }
  71
  72 static struct irq_chip frv_fpga_pic = {
  73         .name           = "mb93091",
  74         .ack            = frv_fpga_ack,
  75         .mask           = frv_fpga_mask,
  76         .mask_ack       = frv_fpga_mask_ack,
  77         .unmask         = frv_fpga_unmask,
  78 };
  79
  80 /*
  81  * FPGA PIC interrupt handler
  82  */
  83 static irqreturn_t fpga_interrupt(int irq, void *_mask)
  84 {
  85         uint16_t imr, mask = (unsigned long) _mask;
  86
  87         imr = __get_IMR();
  88         mask = mask & ~imr & __get_IFR();
  89
  90         /* poll all the triggered IRQs */
  91         while (mask) {
  92                 int irq;
  93
  94                 asm("scan %1,gr0,%0" : "=r"(irq) : "r"(mask));
  95                 irq = 31 - irq;
  96                 mask &= ~(1 << irq);
  97
  98                 generic_handle_irq(IRQ_BASE_FPGA + irq);
  99         }
 100
 101         return IRQ_HANDLED;
 102 }
 103
 104 /*
 105  * define an interrupt action for each FPGA PIC output
 106  * - use dev_id to indicate the FPGA PIC input to output mappings
 107  */
 108 static struct irqaction fpga_irq[4]  = {
 109         [0] = {
 110                 .handler        = fpga_interrupt,
 111                 .flags          = IRQF_DISABLED | IRQF_SHARED,
 112                 .mask           = CPU_MASK_NONE,
 113                 .name           = "fpga.0",
 114                 .dev_id         = (void *) 0x0028UL,
 115         },
 116         [1] = {
 117                 .handler        = fpga_interrupt,
 118                 .flags          = IRQF_DISABLED | IRQF_SHARED,
 119                 .mask           = CPU_MASK_NONE,
 120                 .name           = "fpga.1",
 121                 .dev_id         = (void *) 0x0050UL,
 122         },
 123         [2] = {
 124                 .handler        = fpga_interrupt,
 125                 .flags          = IRQF_DISABLED | IRQF_SHARED,
 126                 .mask           = CPU_MASK_NONE,
 127                 .name           = "fpga.2",
 128                 .dev_id         = (void *) 0x1c00UL,
 129         },
 130         [3] = {
 131                 .handler        = fpga_interrupt,
 132                 .flags          = IRQF_DISABLED | IRQF_SHARED,
 133                 .mask           = CPU_MASK_NONE,
 134                 .name           = "fpga.3",
 135                 .dev_id         = (void *) 0x6386UL,
 136         }
 137 };
 138
 139 /*
 140  * initialise the motherboard FPGA's PIC
 141  */
 142 void __init fpga_init(void)
 143 {
 144         int irq;
 145
 146         /* all PIC inputs are all set to be low-level driven, apart from the
 147          * NMI button (15) which is fixed at falling-edge
 148          */
 149         __set_IMR(0x7ffe);
 150         __clr_IFR(0x0000);
 151
 152         for (irq = IRQ_BASE_FPGA + 1; irq <= IRQ_BASE_FPGA + 14; irq++)
 153                 set_irq_chip_and_handler(irq, &frv_fpga_pic, handle_level_irq);
 154
 155         set_irq_chip_and_handler(IRQ_FPGA_NMI, &frv_fpga_pic, handle_edge_irq);
 156
 157         /* the FPGA drives the first four external IRQ inputs on the CPU PIC */
 158         setup_irq(IRQ_CPU_EXTERNAL0, &fpga_irq[0]);
 159         setup_irq(IRQ_CPU_EXTERNAL1, &fpga_irq[1]);
 160         setup_irq(IRQ_CPU_EXTERNAL2, &fpga_irq[2]);
 161         setup_irq(IRQ_CPU_EXTERNAL3, &fpga_irq[3]);
 162 }