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("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         printk("Killing all PSC DMA channels...");
  63         for (i = 0 ; i < 9 ; i++) {
  64                 psc_write_word(PSC_CTL_BASE + (i << 4), 0x8800);
  65                 psc_write_word(PSC_CTL_BASE + (i << 4), 0x1000);
  66                 psc_write_word(PSC_CMD_BASE + (i << 5), 0x1100);
  67                 psc_write_word(PSC_CMD_BASE + (i << 5) + 0x10, 0x1100);
  68         }
  69         printk("done!\n");
  70 }
  71
  72 /*
  73  * Initialize the PSC. For now this just involves shutting down all
  74  * interrupt sources using the IERs.
  75  */
  76
  77 void __init psc_init(void)
  78 {
  79         int i;
  80
  81         if (macintosh_config->ident != MAC_MODEL_C660
  82          && macintosh_config->ident != MAC_MODEL_Q840)
  83         {
  84                 psc = NULL;
  85                 return;
  86         }
  87
  88         /*
  89          * The PSC is always at the same spot, but using psc
  90          * keeps things consistent with the psc_xxxx functions.
  91          */
  92
  93         psc = (void *) PSC_BASE;
  94
  95         printk("PSC detected at %p\n", psc);
  96
  97         psc_dma_die_die_die();
  98
  99 #ifdef DEBUG_PSC
 100         psc_debug_dump();
 101 #endif
 102         /*
 103          * Mask and clear all possible interrupts
 104          */
 105
 106         for (i = 0x30 ; i < 0x70 ; i += 0x10) {
 107                 psc_write_byte(pIERbase + i, 0x0F);
 108                 psc_write_byte(pIFRbase + i, 0x0F);
 109         }
 110 }
 111
 112 /*
 113  * PSC interrupt handler. It's a lot like the VIA interrupt handler.
 114  */
 115
 116 static void psc_irq(struct irq_desc *desc)
 117 {
 118         unsigned int offset = (unsigned int)irq_desc_get_handler_data(desc);
 119         unsigned int irq = irq_desc_get_irq(desc);
 120         int pIFR        = pIFRbase + offset;
 121         int pIER        = pIERbase + offset;
 122         int irq_num;
 123         unsigned char irq_bit, events;
 124
 125         events = psc_read_byte(pIFR) & psc_read_byte(pIER) & 0xF;
 126         if (!events)
 127                 return;
 128
 129         irq_num = irq << 3;
 130         irq_bit = 1;
 131         do {
 132                 if (events & irq_bit) {
 133                         psc_write_byte(pIFR, irq_bit);
 134                         generic_handle_irq(irq_num);
 135                 }
 136                 irq_num++;
 137                 irq_bit <<= 1;
 138         } while (events >= irq_bit);
 139 }
 140
 141 /*
 142  * Register the PSC interrupt dispatchers for autovector interrupts 3-6.
 143  */
 144
 145 void __init psc_register_interrupts(void)
 146 {
 147         irq_set_chained_handler_and_data(IRQ_AUTO_3, psc_irq, (void *)0x30);
 148         irq_set_chained_handler_and_data(IRQ_AUTO_4, psc_irq, (void *)0x40);
 149         irq_set_chained_handler_and_data(IRQ_AUTO_5, psc_irq, (void *)0x50);
 150         irq_set_chained_handler_and_data(IRQ_AUTO_6, psc_irq, (void *)0x60);
 151 }
 152
 153 void psc_irq_enable(int irq) {
 154         int irq_src     = IRQ_SRC(irq);
 155         int irq_idx     = IRQ_IDX(irq);
 156         int pIER        = pIERbase + (irq_src << 4);
 157
 158         psc_write_byte(pIER, (1 << irq_idx) | 0x80);
 159 }
 160
 161 void psc_irq_disable(int irq) {
 162         int irq_src     = IRQ_SRC(irq);
 163         int irq_idx     = IRQ_IDX(irq);
 164         int pIER        = pIERbase + (irq_src << 4);
 165
 166         psc_write_byte(pIER, 1 << irq_idx);
 167 }