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/delay.h>
  24 #include <asm/irq.h>
  25 #include <asm/irc-regs.h>
  26
  27 #define __reg16(ADDR) (*(volatile unsigned short *)(__region_CS2 + (ADDR)))
  28
  29 #define __get_IMR()     ({ __reg16(0x0a); })
  30 #define __set_IMR(M)    do { __reg16(0x0a) = (M);  wmb(); } while(0)
  31 #define __get_IFR()     ({ __reg16(0x02); })
  32 #define __clr_IFR(M)    do { __reg16(0x02) = ~(M); wmb(); } while(0)
  33
  34 /*
  35  * off-CPU FPGA PIC operations
  36  */
  37 static void frv_fpga_mask(struct irq_data *d)
  38 {
  39         uint16_t imr = __get_IMR();
  40
  41         imr |= 1 << (d->irq - IRQ_BASE_FPGA);
  42         __set_IMR(imr);
  43 }
  44
  45 static void frv_fpga_ack(struct irq_data *d)
  46 {
  47         __clr_IFR(1 << (d->irq - IRQ_BASE_FPGA));
  48 }
  49
  50 static void frv_fpga_mask_ack(struct irq_data *d)
  51 {
  52         uint16_t imr = __get_IMR();
  53
  54         imr |= 1 << (d->irq - IRQ_BASE_FPGA);
  55         __set_IMR(imr);
  56
  57         __clr_IFR(1 << (d->irq - IRQ_BASE_FPGA));
  58 }
  59
  60 static void frv_fpga_unmask(struct irq_data *d)
  61 {
  62         uint16_t imr = __get_IMR();
  63
  64         imr &= ~(1 << (d->irq - IRQ_BASE_FPGA));
  65
  66         __set_IMR(imr);
  67 }
  68
  69 static struct irq_chip frv_fpga_pic = {
  70         .name           = "mb93093",
  71         .irq_ack        = frv_fpga_ack,
  72         .irq_mask       = frv_fpga_mask,
  73         .irq_mask_ack   = frv_fpga_mask_ack,
  74         .irq_unmask     = frv_fpga_unmask,
  75 };
  76
  77 /*
  78  * FPGA PIC interrupt handler
  79  */
  80 static irqreturn_t fpga_interrupt(int irq, void *_mask)
  81 {
  82         uint16_t imr, mask = (unsigned long) _mask;
  83
  84         imr = __get_IMR();
  85         mask = mask & ~imr & __get_IFR();
  86
  87         /* poll all the triggered IRQs */
  88         while (mask) {
  89                 int irq;
  90
  91                 asm("scan %1,gr0,%0" : "=r"(irq) : "r"(mask));
  92                 irq = 31 - irq;
  93                 mask &= ~(1 << irq);
  94
  95                 generic_handle_irq(IRQ_BASE_FPGA + irq);
  96         }
  97
  98         return IRQ_HANDLED;
  99 }
 100
 101 /*
 102  * define an interrupt action for each FPGA PIC output
 103  * - use dev_id to indicate the FPGA PIC input to output mappings
 104  */
 105 static struct irqaction fpga_irq[1]  = {
 106         [0] = {
 107                 .handler        = fpga_interrupt,
 108                 .flags          = IRQF_DISABLED,
 109                 .name           = "fpga.0",
 110                 .dev_id         = (void *) 0x0700UL,
 111         }
 112 };
 113
 114 /*
 115  * initialise the motherboard FPGA's PIC
 116  */
 117 void __init fpga_init(void)
 118 {
 119         int irq;
 120
 121         /* all PIC inputs are all set to be edge triggered */
 122         __set_IMR(0x0700);
 123         __clr_IFR(0x0000);
 124
 125         for (irq = IRQ_BASE_FPGA + 8; irq <= IRQ_BASE_FPGA + 10; irq++)
 126                 irq_set_chip_and_handler(irq, &frv_fpga_pic, handle_edge_irq);
 127
 128         /* the FPGA drives external IRQ input #2 on the CPU PIC */
 129         setup_irq(IRQ_CPU_EXTERNAL2, &fpga_irq[0]);
 130 }