arch/ppc/platforms/adir_pic.c

   1 /*
   2  * arch/ppc/platforms/adir_pic.c
   3  *
   4  * Interrupt controller support for SBS Adirondack
   5  *
   6  * By Michael Sokolov <msokolov@ivan.Harhan.ORG>
   7  * based on the K2 and SCM versions by Matt Porter <mporter@mvista.com>
   8  */
   9
  10 #include <linux/stddef.h>
  11 #include <linux/init.h>
  12 #include <linux/sched.h>
  13 #include <linux/pci.h>
  14 #include <linux/irq.h>
  15
  16 #include <asm/io.h>
  17 #include <asm/i8259.h>
  18 #include "adir.h"
  19
  20 static void adir_onboard_pic_enable(unsigned int irq);
  21 static void adir_onboard_pic_disable(unsigned int irq);
  22
  23 static void
  24 no_action(int cpl, void *dev_id, struct pt_regs *regs)
  25 {
  26 }
  27
  28 __init static void
  29 adir_onboard_pic_init(void)
  30 {
  31         volatile u_short *maskreg = (volatile u_short *) ADIR_PROCA_INT_MASK;
  32
  33         /* Disable all Adirondack onboard interrupts */
  34         out_be16(maskreg, 0xFFFF);
  35 }
  36
  37 static int
  38 adir_onboard_pic_get_irq(void)
  39 {
  40         volatile u_short *statreg = (volatile u_short *) ADIR_PROCA_INT_STAT;
  41         int irq;
  42         u_short int_status, int_test;
  43
  44         int_status = in_be16(statreg);
  45         for (irq = 0, int_test = 1; irq < 16; irq++, int_test <<= 1) {
  46                 if (int_status & int_test)
  47                         break;
  48         }
  49
  50         if (irq == 16)
  51                 return -1;
  52
  53         return (irq+16);
  54 }
  55
  56 static void
  57 adir_onboard_pic_enable(unsigned int irq)
  58 {
  59         volatile u_short *maskreg = (volatile u_short *) ADIR_PROCA_INT_MASK;
  60
  61         /* Change irq to Adirondack onboard native value */
  62         irq -= 16;
  63
  64         /* Enable requested irq number */
  65         out_be16(maskreg, in_be16(maskreg) & ~(1 << irq));
  66 }
  67
  68 static void
  69 adir_onboard_pic_disable(unsigned int irq)
  70 {
  71         volatile u_short *maskreg = (volatile u_short *) ADIR_PROCA_INT_MASK;
  72
  73         /* Change irq to Adirondack onboard native value */
  74         irq -= 16;
  75
  76         /* Disable requested irq number */
  77         out_be16(maskreg, in_be16(maskreg) | (1 << irq));
  78 }
  79
  80 static struct hw_interrupt_type adir_onboard_pic = {
  81         " ADIR PIC ",
  82         NULL,
  83         NULL,
  84         adir_onboard_pic_enable,                /* unmask */
  85         adir_onboard_pic_disable,               /* mask */
  86         adir_onboard_pic_disable,               /* mask and ack */
  87         NULL,
  88         NULL
  89 };
  90
  91 /*
  92  * Linux interrupt values are assigned as follows:
  93  *
  94  *      0-15            VT82C686 8259 interrupts
  95  *      16-31           Adirondack CPLD interrupts
  96  */
  97 __init void
  98 adir_init_IRQ(void)
  99 {
 100         int     i;
 101
 102         /* Initialize the cascaded 8259's on the VT82C686 */
 103         for (i=0; i<16; i++)
 104                 irq_desc[i].handler = &i8259_pic;
 105         i8259_init(NULL);
 106
 107         /* Initialize Adirondack CPLD PIC and enable 8259 interrupt cascade */
 108         for (i=16; i<32; i++)
 109                 irq_desc[i].handler = &adir_onboard_pic;
 110         adir_onboard_pic_init();
 111
 112         /* Enable 8259 interrupt cascade */
 113         request_irq(ADIR_IRQ_VT82C686_INTR,
 114                         no_action,
 115                         SA_INTERRUPT,
 116                         "82c59 primary cascade",
 117                         NULL);
 118 }
 119
 120 int
 121 adir_get_irq(struct pt_regs *regs)
 122 {
 123         int     irq;
 124
 125         if ((irq = adir_onboard_pic_get_irq()) < 0)
 126                 return irq;
 127
 128         if (irq == ADIR_IRQ_VT82C686_INTR)
 129                 irq = i8259_irq(regs);
 130
 131         return irq;
 132 }