arch/m68k/mac/psc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *      Apple Peripheral System Controller (PSC)
   4  *
   5  *      The PSC is used on the AV Macs to control IO functions not handled
   6  *      by the VIAs (Ethernet, DSP, SCC).
   7  *
   8  * TO DO:
   9  *
  10  * Try to figure out what's going on in pIFR5 and pIFR6. There seem to be
  11  * persisant interrupt conditions in those registers and I have no idea what
  12  * they are. Granted it doesn't affect since we're not enabling any interrupts
  13  * on those levels at the moment, but it would be nice to know. I have a feeling
  14  * they aren't actually interrupt lines but data lines (to the DSP?)
  15  */
  16
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/mm.h>
  20 #include <linux/delay.h>
  21 #include <linux/init.h>
  22 #include <linux/irq.h>
  23
  24 #include <asm/traps.h>
  25 #include <asm/macintosh.h>
  26 #include <asm/macints.h>
  27 #include <asm/mac_psc.h>
  28
  29 #include "mac.h"
  30
  31 #define DEBUG_PSC
  32
  33 volatile __u8 *psc;
  34 EXPORT_SYMBOL_GPL(psc);
  35
  36 /*
  37  * Debugging dump, used in various places to see what's going on.
  38  */
  39
  40 static void psc_debug_dump(void)
  41 {
  42         int     i;
  43
  44         if (!psc)
  45                 return;
  46
  47         for (i = 0x30 ; i < 0x70 ; i += 0x10) {
  48                 printk(KERN_DEBUG "PSC #%d:  IFR = 0x%02X IER = 0x%02X\n",
  49                         i >> 4,
  50                         (int) psc_read_byte(pIFRbase + i),
  51                         (int) psc_read_byte(pIERbase + i));
  52         }
  53 }
  54
  55 /*
  56  * Try to kill all DMA channels on the PSC. Not sure how this his
  57  * supposed to work; this is code lifted from macmace.c and then
  58  * expanded to cover what I think are the other 7 channels.
  59  */
  60
  61 static __init void psc_dma_die_die_die(void)
  62 {
  63         int i;
  64
  65         for (i = 0 ; i < 9 ; i++) {
  66                 psc_write_word(PSC_CTL_BASE + (i << 4), 0x8800);
  67                 psc_write_word(PSC_CTL_BASE + (i << 4), 0x1000);
  68                 psc_write_word(PSC_CMD_BASE + (i << 5), 0x1100);
  69                 psc_write_word(PSC_CMD_BASE + (i << 5) + 0x10, 0x1100);
  70         }
  71 }
  72
  73 /*
  74  * Initialize the PSC. For now this just involves shutting down all
  75  * interrupt sources using the IERs.
  76  */
  77
  78 void __init psc_init(void)
  79 {
  80         int i;
  81
  82         if (macintosh_config->ident != MAC_MODEL_C660
  83          && macintosh_config->ident != MAC_MODEL_Q840)
  84         {
  85                 psc = NULL;
  86                 return;
  87         }
  88
  89         /*
  90          * The PSC is always at the same spot, but using psc
  91          * keeps things consistent with the psc_xxxx functions.
  92          */
  93
  94         psc = (void *) PSC_BASE;
  95
  96         pr_debug("PSC detected at %p\n", psc);
  97
  98         psc_dma_die_die_die();
  99
 100 #ifdef DEBUG_PSC
 101         psc_debug_dump();
 102 #endif
 103         /*
 104          * Mask and clear all possible interrupts
 105          */
 106
 107         for (i = 0x30 ; i < 0x70 ; i += 0x10) {
 108                 psc_write_byte(pIERbase + i, 0x0F);
 109                 psc_write_byte(pIFRbase + i, 0x0F);
 110         }
 111 }
 112
 113 /*
 114  * PSC interrupt handler. It's a lot like the VIA interrupt handler.
 115  */
 116
 117 static void psc_irq(struct irq_desc *desc)
 118 {
 119         unsigned int offset = (unsigned int)irq_desc_get_handler_data(desc);
 120         unsigned int irq = irq_desc_get_irq(desc);
 121         int pIFR        = pIFRbase + offset;
 122         int pIER        = pIERbase + offset;
 123         int irq_num;
 124         unsigned char irq_bit, events;
 125
 126         events = psc_read_byte(pIFR) & psc_read_byte(pIER) & 0xF;
 127         if (!events)
 128                 return;
 129
 130         irq_num = irq << 3;
 131         irq_bit = 1;
 132         do {
 133                 if (events & irq_bit) {
 134                         psc_write_byte(pIFR, irq_bit);
 135                         generic_handle_irq(irq_num);
 136                 }
 137                 irq_num++;
 138                 irq_bit <<= 1;
 139         } while (events >= irq_bit);
 140 }
 141
 142 /*
 143  * Register the PSC interrupt dispatchers for autovector interrupts 3-6.
 144  */
 145
 146 void __init psc_register_interrupts(void)
 147 {
 148         irq_set_chained_handler_and_data(IRQ_AUTO_3, psc_irq, (void *)0x30);
 149         irq_set_chained_handler_and_data(IRQ_AUTO_4, psc_irq, (void *)0x40);
 150         irq_set_chained_handler_and_data(IRQ_AUTO_5, psc_irq, (void *)0x50);
 151         irq_set_chained_handler_and_data(IRQ_AUTO_6, psc_irq, (void *)0x60);
 152 }
 153
 154 void psc_irq_enable(int irq) {
 155         int irq_src     = IRQ_SRC(irq);
 156         int irq_idx     = IRQ_IDX(irq);
 157         int pIER        = pIERbase + (irq_src << 4);
 158
 159         psc_write_byte(pIER, (1 << irq_idx) | 0x80);
 160 }
 161
 162 void psc_irq_disable(int irq) {
 163         int irq_src     = IRQ_SRC(irq);
 164         int irq_idx     = IRQ_IDX(irq);
 165         int pIER        = pIERbase + (irq_src << 4);
 166
 167         psc_write_byte(pIER, 1 << irq_idx);
 168 }