arch/m68k/mac/psc.c

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