arch/ppc/syslib/cpm2_pic.c

   1 /* The CPM2 internal interrupt controller.  It is usually
   2  * the only interrupt controller.
   3  * There are two 32-bit registers (high/low) for up to 64
   4  * possible interrupts.
   5  *
   6  * Now, the fun starts.....Interrupt Numbers DO NOT MAP
   7  * in a simple arithmetic fashion to mask or pending registers.
   8  * That is, interrupt 4 does not map to bit position 4.
   9  * We create two tables, indexed by vector number, to indicate
  10  * which register to use and which bit in the register to use.
  11  */
  12
  13 #include <linux/stddef.h>
  14 #include <linux/init.h>
  15 #include <linux/sched.h>
  16 #include <linux/signal.h>
  17 #include <linux/irq.h>
  18
  19 #include <asm/immap_cpm2.h>
  20 #include <asm/mpc8260.h>
  21
  22 #include "cpm2_pic.h"
  23
  24 static  u_char  irq_to_siureg[] = {
  25         1, 1, 1, 1, 1, 1, 1, 1,
  26         1, 1, 1, 1, 1, 1, 1, 1,
  27         0, 0, 0, 0, 0, 0, 0, 0,
  28         0, 0, 0, 0, 0, 0, 0, 0,
  29         1, 1, 1, 1, 1, 1, 1, 1,
  30         1, 1, 1, 1, 1, 1, 1, 1,
  31         0, 0, 0, 0, 0, 0, 0, 0,
  32         0, 0, 0, 0, 0, 0, 0, 0
  33 };
  34
  35 /* bit numbers do not match the docs, these are precomputed so the bit for
  36  * a given irq is (1 << irq_to_siubit[irq]) */
  37 static  u_char  irq_to_siubit[] = {
  38          0, 15, 14, 13, 12, 11, 10,  9,
  39          8,  7,  6,  5,  4,  3,  2,  1,
  40          2,  1,  0, 14, 13, 12, 11, 10,
  41          9,  8,  7,  6,  5,  4,  3,  0,
  42         31, 30, 29, 28, 27, 26, 25, 24,
  43         23, 22, 21, 20, 19, 18, 17, 16,
  44         16, 17, 18, 19, 20, 21, 22, 23,
  45         24, 25, 26, 27, 28, 29, 30, 31,
  46 };
  47
  48 static void cpm2_mask_irq(unsigned int irq_nr)
  49 {
  50         int     bit, word;
  51         volatile uint   *simr;
  52
  53         irq_nr -= CPM_IRQ_OFFSET;
  54
  55         bit = irq_to_siubit[irq_nr];
  56         word = irq_to_siureg[irq_nr];
  57
  58         simr = &(cpm2_immr->im_intctl.ic_simrh);
  59         ppc_cached_irq_mask[word] &= ~(1 << bit);
  60         simr[word] = ppc_cached_irq_mask[word];
  61 }
  62
  63 static void cpm2_unmask_irq(unsigned int irq_nr)
  64 {
  65         int     bit, word;
  66         volatile uint   *simr;
  67
  68         irq_nr -= CPM_IRQ_OFFSET;
  69
  70         bit = irq_to_siubit[irq_nr];
  71         word = irq_to_siureg[irq_nr];
  72
  73         simr = &(cpm2_immr->im_intctl.ic_simrh);
  74         ppc_cached_irq_mask[word] |= 1 << bit;
  75         simr[word] = ppc_cached_irq_mask[word];
  76 }
  77
  78 static void cpm2_mask_and_ack(unsigned int irq_nr)
  79 {
  80         int     bit, word;
  81         volatile uint   *simr, *sipnr;
  82
  83         irq_nr -= CPM_IRQ_OFFSET;
  84
  85         bit = irq_to_siubit[irq_nr];
  86         word = irq_to_siureg[irq_nr];
  87
  88         simr = &(cpm2_immr->im_intctl.ic_simrh);
  89         sipnr = &(cpm2_immr->im_intctl.ic_sipnrh);
  90         ppc_cached_irq_mask[word] &= ~(1 << bit);
  91         simr[word] = ppc_cached_irq_mask[word];
  92         sipnr[word] = 1 << bit;
  93 }
  94
  95 static void cpm2_end_irq(unsigned int irq_nr)
  96 {
  97         int     bit, word;
  98         volatile uint   *simr;
  99
 100         if (!(irq_desc[irq_nr].status & (IRQ_DISABLED|IRQ_INPROGRESS))
 101                         && irq_desc[irq_nr].action) {
 102
 103                 irq_nr -= CPM_IRQ_OFFSET;
 104                 bit = irq_to_siubit[irq_nr];
 105                 word = irq_to_siureg[irq_nr];
 106
 107                 simr = &(cpm2_immr->im_intctl.ic_simrh);
 108                 ppc_cached_irq_mask[word] |= 1 << bit;
 109                 simr[word] = ppc_cached_irq_mask[word];
 110                 /*
 111                  * Work around large numbers of spurious IRQs on PowerPC 82xx
 112                  * systems.
 113                  */
 114                 mb();
 115         }
 116 }
 117
 118 static struct hw_interrupt_type cpm2_pic = {
 119         .typename = " CPM2 SIU ",
 120         .enable = cpm2_unmask_irq,
 121         .disable = cpm2_mask_irq,
 122         .ack = cpm2_mask_and_ack,
 123         .end = cpm2_end_irq,
 124 };
 125
 126 int cpm2_get_irq(struct pt_regs *regs)
 127 {
 128         int irq;
 129         unsigned long bits;
 130
 131         /* For CPM2, read the SIVEC register and shift the bits down
 132          * to get the irq number.         */
 133         bits = cpm2_immr->im_intctl.ic_sivec;
 134         irq = bits >> 26;
 135
 136         if (irq == 0)
 137                 return(-1);
 138         return irq+CPM_IRQ_OFFSET;
 139 }
 140
 141 void cpm2_init_IRQ(void)
 142 {
 143         int i;
 144
 145         /* Clear the CPM IRQ controller, in case it has any bits set
 146          * from the bootloader
 147          */
 148
 149         /* Mask out everything */
 150         cpm2_immr->im_intctl.ic_simrh = 0x00000000;
 151         cpm2_immr->im_intctl.ic_simrl = 0x00000000;
 152         wmb();
 153
 154         /* Ack everything */
 155         cpm2_immr->im_intctl.ic_sipnrh = 0xffffffff;
 156         cpm2_immr->im_intctl.ic_sipnrl = 0xffffffff;
 157         wmb();
 158
 159         /* Dummy read of the vector */
 160         i = cpm2_immr->im_intctl.ic_sivec;
 161         rmb();
 162
 163         /* Initialize the default interrupt mapping priorities,
 164          * in case the boot rom changed something on us.
 165          */
 166         cpm2_immr->im_intctl.ic_sicr = 0;
 167         cpm2_immr->im_intctl.ic_scprrh = 0x05309770;
 168         cpm2_immr->im_intctl.ic_scprrl = 0x05309770;
 169
 170
 171         /* Enable chaining to OpenPIC, and make everything level
 172          */
 173         for (i = 0; i < NR_CPM_INTS; i++) {
 174                 irq_desc[i+CPM_IRQ_OFFSET].chip = &cpm2_pic;
 175                 irq_desc[i+CPM_IRQ_OFFSET].status |= IRQ_LEVEL;
 176         }
 177 }