arch/m68k/mac/baboon.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Baboon Custom IC Management
   4  *
   5  * The Baboon custom IC controls the IDE, PCMCIA and media bay on the
   6  * PowerBook 190. It multiplexes multiple interrupt sources onto the
   7  * Nubus slot $C interrupt.
   8  */
   9
  10 #include <linux/types.h>
  11 #include <linux/kernel.h>
  12 #include <linux/irq.h>
  13
  14 #include <asm/macintosh.h>
  15 #include <asm/macints.h>
  16 #include <asm/mac_baboon.h>
  17
  18 int baboon_present;
  19 static volatile struct baboon *baboon;
  20
  21 /*
  22  * Baboon initialization.
  23  */
  24
  25 void __init baboon_init(void)
  26 {
  27         if (macintosh_config->ident != MAC_MODEL_PB190) {
  28                 baboon = NULL;
  29                 baboon_present = 0;
  30                 return;
  31         }
  32
  33         baboon = (struct baboon *) BABOON_BASE;
  34         baboon_present = 1;
  35
  36         pr_debug("Baboon detected at %p\n", baboon);
  37 }
  38
  39 /*
  40  * Baboon interrupt handler.
  41  * XXX how do you clear a pending IRQ? is it even necessary?
  42  */
  43
  44 static void baboon_irq(struct irq_desc *desc)
  45 {
  46         short events, irq_bit;
  47         int irq_num;
  48
  49         events = baboon->mb_ifr & 0x07;
  50         irq_num = IRQ_BABOON_0;
  51         irq_bit = 1;
  52         do {
  53                 if (events & irq_bit) {
  54                         events &= ~irq_bit;
  55                         generic_handle_irq(irq_num);
  56                 }
  57                 ++irq_num;
  58                 irq_bit <<= 1;
  59         } while (events);
  60 }
  61
  62 /*
  63  * Register the Baboon interrupt dispatcher on nubus slot $C.
  64  */
  65
  66 void __init baboon_register_interrupts(void)
  67 {
  68         irq_set_chained_handler(IRQ_NUBUS_C, baboon_irq);
  69 }
  70
  71 /*
  72  * The means for masking individual Baboon interrupts remains a mystery.
  73  * However, since we only use the IDE IRQ, we can just enable/disable all
  74  * Baboon interrupts. If/when we handle more than one Baboon IRQ, we must
  75  * either figure out how to mask them individually or else implement the
  76  * same workaround that's used for NuBus slots (see nubus_disabled and
  77  * via_nubus_irq_shutdown).
  78  */
  79
  80 void baboon_irq_enable(int irq)
  81 {
  82         mac_irq_enable(irq_get_irq_data(IRQ_NUBUS_C));
  83 }
  84
  85 void baboon_irq_disable(int irq)
  86 {
  87         mac_irq_disable(irq_get_irq_data(IRQ_NUBUS_C));
  88 }