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  */
  38 static 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
  46 static void frv_fpga_ack(unsigned int irq)
  47 {
  48         __clr_IFR(1 << (irq - IRQ_BASE_FPGA));
  49 }
  50
  51 static 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
  61 static 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
  70 static 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  */
  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_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  */
 107 static 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  */
 119 void __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 }