arch/m68k/amiga/cia.c

   1 /*
   2  *  linux/arch/m68k/amiga/cia.c - CIA support
   3  *
   4  *  Copyright (C) 1996 Roman Zippel
   5  *
   6  *  The concept of some functions bases on the original Amiga OS function
   7  *
   8  * This file is subject to the terms and conditions of the GNU General Public
   9  * License.  See the file COPYING in the main directory of this archive
  10  * for more details.
  11  */
  12
  13 #include <linux/types.h>
  14 #include <linux/kernel.h>
  15 #include <linux/sched.h>
  16 #include <linux/errno.h>
  17 #include <linux/kernel_stat.h>
  18 #include <linux/init.h>
  19 #include <linux/seq_file.h>
  20 #include <linux/interrupt.h>
  21
  22 #include <asm/irq.h>
  23 #include <asm/amigahw.h>
  24 #include <asm/amigaints.h>
  25
  26 struct ciabase {
  27         volatile struct CIA *cia;
  28         unsigned char icr_mask, icr_data;
  29         unsigned short int_mask;
  30         int handler_irq, cia_irq, server_irq;
  31         char *name;
  32 } ciaa_base = {
  33         .cia            = &ciaa,
  34         .int_mask       = IF_PORTS,
  35         .handler_irq    = IRQ_AMIGA_PORTS,
  36         .cia_irq        = IRQ_AMIGA_CIAA,
  37         .name           = "CIAA"
  38 }, ciab_base = {
  39         .cia            = &ciab,
  40         .int_mask       = IF_EXTER,
  41         .handler_irq    = IRQ_AMIGA_EXTER,
  42         .cia_irq        = IRQ_AMIGA_CIAB,
  43         .name           = "CIAB"
  44 };
  45
  46 /*
  47  *  Cause or clear CIA interrupts, return old interrupt status.
  48  */
  49
  50 unsigned char cia_set_irq(struct ciabase *base, unsigned char mask)
  51 {
  52         unsigned char old;
  53
  54         old = (base->icr_data |= base->cia->icr);
  55         if (mask & CIA_ICR_SETCLR)
  56                 base->icr_data |= mask;
  57         else
  58                 base->icr_data &= ~mask;
  59         if (base->icr_data & base->icr_mask)
  60                 amiga_custom.intreq = IF_SETCLR | base->int_mask;
  61         return old & base->icr_mask;
  62 }
  63
  64 /*
  65  *  Enable or disable CIA interrupts, return old interrupt mask,
  66  */
  67
  68 unsigned char cia_able_irq(struct ciabase *base, unsigned char mask)
  69 {
  70         unsigned char old;
  71
  72         old = base->icr_mask;
  73         base->icr_data |= base->cia->icr;
  74         base->cia->icr = mask;
  75         if (mask & CIA_ICR_SETCLR)
  76                 base->icr_mask |= mask;
  77         else
  78                 base->icr_mask &= ~mask;
  79         base->icr_mask &= CIA_ICR_ALL;
  80         if (base->icr_data & base->icr_mask)
  81                 amiga_custom.intreq = IF_SETCLR | base->int_mask;
  82         return old;
  83 }
  84
  85 static irqreturn_t cia_handler(int irq, void *dev_id, struct pt_regs *fp)
  86 {
  87         struct ciabase *base = (struct ciabase *)dev_id;
  88         int mach_irq;
  89         unsigned char ints;
  90
  91         mach_irq = base->cia_irq;
  92         ints = cia_set_irq(base, CIA_ICR_ALL);
  93         amiga_custom.intreq = base->int_mask;
  94         for (; ints; mach_irq++, ints >>= 1) {
  95                 if (ints & 1)
  96                         m68k_handle_int(mach_irq, fp);
  97         }
  98         return IRQ_HANDLED;
  99 }
 100
 101 static void cia_enable_irq(unsigned int irq)
 102 {
 103         unsigned char mask;
 104
 105         if (irq >= IRQ_AMIGA_CIAB) {
 106                 mask = 1 << (irq - IRQ_AMIGA_CIAB);
 107                 cia_set_irq(&ciab_base, mask);
 108                 cia_able_irq(&ciab_base, CIA_ICR_SETCLR | mask);
 109         } else {
 110                 mask = 1 << (irq - IRQ_AMIGA_CIAA);
 111                 cia_set_irq(&ciaa_base, mask);
 112                 cia_able_irq(&ciaa_base, CIA_ICR_SETCLR | mask);
 113         }
 114 }
 115
 116 static void cia_disable_irq(unsigned int irq)
 117 {
 118         if (irq >= IRQ_AMIGA_CIAB)
 119                 cia_able_irq(&ciab_base, 1 << (irq - IRQ_AMIGA_CIAB));
 120         else
 121                 cia_able_irq(&ciaa_base, 1 << (irq - IRQ_AMIGA_CIAA));
 122 }
 123
 124 static struct irq_controller cia_irq_controller = {
 125         .name           = "cia",
 126         .lock           = SPIN_LOCK_UNLOCKED,
 127         .enable         = cia_enable_irq,
 128         .disable        = cia_disable_irq,
 129 };
 130
 131 /*
 132  * Override auto irq 2 & 6 and use them as general chain
 133  * for external interrupts, we link the CIA interrupt sources
 134  * into this chain.
 135  */
 136
 137 static void auto_enable_irq(unsigned int irq)
 138 {
 139         switch (irq) {
 140         case IRQ_AUTO_2:
 141                 amiga_custom.intena = IF_SETCLR | IF_PORTS;
 142                 break;
 143         case IRQ_AUTO_6:
 144                 amiga_custom.intena = IF_SETCLR | IF_EXTER;
 145                 break;
 146         }
 147 }
 148
 149 static void auto_disable_irq(unsigned int irq)
 150 {
 151         switch (irq) {
 152         case IRQ_AUTO_2:
 153                 amiga_custom.intena = IF_PORTS;
 154                 break;
 155         case IRQ_AUTO_6:
 156                 amiga_custom.intena = IF_EXTER;
 157                 break;
 158         }
 159 }
 160
 161 static struct irq_controller auto_irq_controller = {
 162         .name           = "auto",
 163         .lock           = SPIN_LOCK_UNLOCKED,
 164         .enable         = auto_enable_irq,
 165         .disable        = auto_disable_irq,
 166 };
 167
 168 void __init cia_init_IRQ(struct ciabase *base)
 169 {
 170         m68k_setup_irq_controller(&cia_irq_controller, base->cia_irq, CIA_IRQS);
 171
 172         /* clear any pending interrupt and turn off all interrupts */
 173         cia_set_irq(base, CIA_ICR_ALL);
 174         cia_able_irq(base, CIA_ICR_ALL);
 175
 176         /* override auto int and install CIA handler */
 177         m68k_setup_irq_controller(&auto_irq_controller, base->handler_irq, 1);
 178         m68k_irq_startup(base->handler_irq);
 179         request_irq(base->handler_irq, cia_handler, IRQF_SHARED, base->name, base);
 180 }