arch/arm/mach-s3c/bast-irq.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 //
   3 // Copyright 2003-2005 Simtec Electronics
   4 //   Ben Dooks <ben@simtec.co.uk>
   5 //
   6 // http://www.simtec.co.uk/products/EB2410ITX/
   7
   8 #include <linux/init.h>
   9 #include <linux/module.h>
  10 #include <linux/ioport.h>
  11 #include <linux/device.h>
  12 #include <linux/io.h>
  13
  14 #include <asm/irq.h>
  15 #include <asm/mach-types.h>
  16 #include <asm/mach/irq.h>
  17
  18 #include "regs-irq.h"
  19 #include <mach/irqs.h>
  20
  21 #include "bast.h"
  22
  23 #define irqdbf(x...)
  24 #define irqdbf2(x...)
  25
  26 /* handle PC104 ISA interrupts from the system CPLD */
  27
  28 /* table of ISA irq nos to the relevant mask... zero means
  29  * the irq is not implemented
  30 */
  31 static const unsigned char bast_pc104_irqmasks[] = {
  32         0,   /* 0 */
  33         0,   /* 1 */
  34         0,   /* 2 */
  35         1,   /* 3 */
  36         0,   /* 4 */
  37         2,   /* 5 */
  38         0,   /* 6 */
  39         4,   /* 7 */
  40         0,   /* 8 */
  41         0,   /* 9 */
  42         8,   /* 10 */
  43         0,   /* 11 */
  44         0,   /* 12 */
  45         0,   /* 13 */
  46         0,   /* 14 */
  47         0,   /* 15 */
  48 };
  49
  50 static const unsigned char bast_pc104_irqs[] = { 3, 5, 7, 10 };
  51
  52 static void
  53 bast_pc104_mask(struct irq_data *data)
  54 {
  55         unsigned long temp;
  56
  57         temp = __raw_readb(BAST_VA_PC104_IRQMASK);
  58         temp &= ~bast_pc104_irqmasks[data->irq];
  59         __raw_writeb(temp, BAST_VA_PC104_IRQMASK);
  60 }
  61
  62 static void
  63 bast_pc104_maskack(struct irq_data *data)
  64 {
  65         struct irq_desc *desc = irq_to_desc(BAST_IRQ_ISA);
  66
  67         bast_pc104_mask(data);
  68         desc->irq_data.chip->irq_ack(&desc->irq_data);
  69 }
  70
  71 static void
  72 bast_pc104_unmask(struct irq_data *data)
  73 {
  74         unsigned long temp;
  75
  76         temp = __raw_readb(BAST_VA_PC104_IRQMASK);
  77         temp |= bast_pc104_irqmasks[data->irq];
  78         __raw_writeb(temp, BAST_VA_PC104_IRQMASK);
  79 }
  80
  81 static struct irq_chip  bast_pc104_chip = {
  82         .irq_mask       = bast_pc104_mask,
  83         .irq_unmask     = bast_pc104_unmask,
  84         .irq_ack        = bast_pc104_maskack
  85 };
  86
  87 static void bast_irq_pc104_demux(struct irq_desc *desc)
  88 {
  89         unsigned int stat;
  90         unsigned int irqno;
  91         int i;
  92
  93         stat = __raw_readb(BAST_VA_PC104_IRQREQ) & 0xf;
  94
  95         if (unlikely(stat == 0)) {
  96                 /* ack if we get an irq with nothing (ie, startup) */
  97                 desc->irq_data.chip->irq_ack(&desc->irq_data);
  98         } else {
  99                 /* handle the IRQ */
 100
 101                 for (i = 0; stat != 0; i++, stat >>= 1) {
 102                         if (stat & 1) {
 103                                 irqno = bast_pc104_irqs[i];
 104                                 generic_handle_irq(irqno);
 105                         }
 106                 }
 107         }
 108 }
 109
 110 static __init int bast_irq_init(void)
 111 {
 112         unsigned int i;
 113
 114         if (machine_is_bast()) {
 115                 printk(KERN_INFO "BAST PC104 IRQ routing, Copyright 2005 Simtec Electronics\n");
 116
 117                 /* zap all the IRQs */
 118
 119                 __raw_writeb(0x0, BAST_VA_PC104_IRQMASK);
 120
 121                 irq_set_chained_handler(BAST_IRQ_ISA, bast_irq_pc104_demux);
 122
 123                 /* register our IRQs */
 124
 125                 for (i = 0; i < 4; i++) {
 126                         unsigned int irqno = bast_pc104_irqs[i];
 127
 128                         irq_set_chip_and_handler(irqno, &bast_pc104_chip,
 129                                                  handle_level_irq);
 130                         irq_clear_status_flags(irqno, IRQ_NOREQUEST);
 131                 }
 132         }
 133
 134         return 0;
 135 }
 136
 137 arch_initcall(bast_irq_init);