arch/sh/boards/overdrive/irq.c

   1 /*
   2  * Copyright (C) 2000 David J. Mckay (david.mckay@st.com)
   3  *
   4  * May be copied or modified under the terms of the GNU General Public
   5  * License.  See linux/COPYING for more information.
   6  *
   7  * Looks after interrupts on the overdrive board.
   8  *
   9  * Bases on the IPR irq system
  10  */
  11
  12 #include <linux/config.h>
  13 #include <linux/init.h>
  14 #include <linux/irq.h>
  15
  16 #include <asm/system.h>
  17 #include <asm/io.h>
  18
  19 #include <asm/overdrive/overdrive.h>
  20
  21 struct od_data {
  22         int overdrive_irq;
  23         int irq_mask;
  24 };
  25
  26 #define NUM_EXTERNAL_IRQS 16
  27 #define EXTERNAL_IRQ_NOT_IN_USE (-1)
  28 #define EXTERNAL_IRQ_NOT_ASSIGNED (-1)
  29
  30 /*
  31  * This table is used to determine what to program into the FPGA's CT register
  32  * for the specified Linux IRQ.
  33  *
  34  * The irq_mask gives the interrupt number from the PCI board (PCI_Int(6:0))
  35  * but is one greater than that because the because the FPGA treats 0
  36  * as disabled, a value of 1 asserts PCI_Int0, and so on.
  37  *
  38  * The overdrive_irq specifies which of the eight interrupt sources generates
  39  * that interrupt, and but is multiplied by four to give the bit offset into
  40  * the CT register.
  41  *
  42  * The seven interrupts levels (SH4 IRL's) we have available here is hardwired
  43  * by the EPLD. The assignments here of which PCI interrupt generates each
  44  * level is arbitary.
  45  */
  46 static struct od_data od_data_table[NUM_EXTERNAL_IRQS] = {
  47         /*    overdrive_irq       , irq_mask */
  48         {EXTERNAL_IRQ_NOT_ASSIGNED, EXTERNAL_IRQ_NOT_IN_USE},   /* 0 */
  49         {EXTERNAL_IRQ_NOT_ASSIGNED, 7}, /* 1 */
  50         {EXTERNAL_IRQ_NOT_ASSIGNED, 6}, /* 2 */
  51         {EXTERNAL_IRQ_NOT_ASSIGNED, EXTERNAL_IRQ_NOT_IN_USE},   /* 3 */
  52         {EXTERNAL_IRQ_NOT_ASSIGNED, 5}, /* 4 */
  53         {EXTERNAL_IRQ_NOT_ASSIGNED, EXTERNAL_IRQ_NOT_IN_USE},   /* 5 */
  54         {EXTERNAL_IRQ_NOT_ASSIGNED, EXTERNAL_IRQ_NOT_IN_USE},   /* 6 */
  55         {EXTERNAL_IRQ_NOT_ASSIGNED, 4}, /* 7 */
  56         {EXTERNAL_IRQ_NOT_ASSIGNED, EXTERNAL_IRQ_NOT_IN_USE},   /* 8 */
  57         {EXTERNAL_IRQ_NOT_ASSIGNED, EXTERNAL_IRQ_NOT_IN_USE},   /* 9 */
  58         {EXTERNAL_IRQ_NOT_ASSIGNED, 3}, /* 10 */
  59         {EXTERNAL_IRQ_NOT_ASSIGNED, 2}, /* 11 */
  60         {EXTERNAL_IRQ_NOT_ASSIGNED, EXTERNAL_IRQ_NOT_IN_USE},   /* 12 */
  61         {EXTERNAL_IRQ_NOT_ASSIGNED, 1}, /* 13 */
  62         {EXTERNAL_IRQ_NOT_ASSIGNED, EXTERNAL_IRQ_NOT_IN_USE},   /* 14 */
  63         {EXTERNAL_IRQ_NOT_ASSIGNED, EXTERNAL_IRQ_NOT_IN_USE}    /* 15 */
  64 };
  65
  66 static void set_od_data(int overdrive_irq, int irq)
  67 {
  68         if (irq >= NUM_EXTERNAL_IRQS || irq < 0)
  69                 return;
  70         od_data_table[irq].overdrive_irq = overdrive_irq << 2;
  71 }
  72
  73 static void enable_od_irq(unsigned int irq);
  74 void disable_od_irq(unsigned int irq);
  75
  76 /* shutdown is same as "disable" */
  77 #define shutdown_od_irq disable_od_irq
  78
  79 static void mask_and_ack_od(unsigned int);
  80 static void end_od_irq(unsigned int irq);
  81
  82 static unsigned int startup_od_irq(unsigned int irq)
  83 {
  84         enable_od_irq(irq);
  85         return 0;               /* never anything pending */
  86 }
  87
  88 static struct hw_interrupt_type od_irq_type = {
  89         .typename = "Overdrive-IRQ",
  90         .startup = startup_od_irq,
  91         .shutdown = shutdown_od_irq,
  92         .enable = enable_od_irq,
  93         .disable = disable_od_irq,
  94         .ack = mask_and_ack_od,
  95         .end = end_od_irq
  96 };
  97
  98 static void disable_od_irq(unsigned int irq)
  99 {
 100         unsigned val, flags;
 101         int overdrive_irq;
 102         unsigned mask;
 103
 104         /* Not a valid interrupt */
 105         if (irq < 0 || irq >= NUM_EXTERNAL_IRQS)
 106                 return;
 107
 108         /* Is is necessary to use a cli here? Would a spinlock not be
 109          * mroe efficient?
 110          */
 111         local_irq_save(flags);
 112         overdrive_irq = od_data_table[irq].overdrive_irq;
 113         if (overdrive_irq != EXTERNAL_IRQ_NOT_ASSIGNED) {
 114                 mask = ~(0x7 << overdrive_irq);
 115                 val = ctrl_inl(OVERDRIVE_INT_CT);
 116                 val &= mask;
 117                 ctrl_outl(val, OVERDRIVE_INT_CT);
 118         }
 119         local_irq_restore(flags);
 120 }
 121
 122 static void enable_od_irq(unsigned int irq)
 123 {
 124         unsigned val, flags;
 125         int overdrive_irq;
 126         unsigned mask;
 127
 128         /* Not a valid interrupt */
 129         if (irq < 0 || irq >= NUM_EXTERNAL_IRQS)
 130                 return;
 131
 132         /* Set priority in OD back to original value */
 133         local_irq_save(flags);
 134         /* This one is not in use currently */
 135         overdrive_irq = od_data_table[irq].overdrive_irq;
 136         if (overdrive_irq != EXTERNAL_IRQ_NOT_ASSIGNED) {
 137                 val = ctrl_inl(OVERDRIVE_INT_CT);
 138                 mask = ~(0x7 << overdrive_irq);
 139                 val &= mask;
 140                 mask = od_data_table[irq].irq_mask << overdrive_irq;
 141                 val |= mask;
 142                 ctrl_outl(val, OVERDRIVE_INT_CT);
 143         }
 144         local_irq_restore(flags);
 145 }
 146
 147
 148
 149 /* this functions sets the desired irq handler to be an overdrive type */
 150 static void __init make_od_irq(unsigned int irq)
 151 {
 152         disable_irq_nosync(irq);
 153         irq_desc[irq].handler = &od_irq_type;
 154         disable_od_irq(irq);
 155 }
 156
 157
 158 static void mask_and_ack_od(unsigned int irq)
 159 {
 160         disable_od_irq(irq);
 161 }
 162
 163 static void end_od_irq(unsigned int irq)
 164 {
 165         enable_od_irq(irq);
 166 }
 167
 168 void __init init_overdrive_irq(void)
 169 {
 170         int i;
 171
 172         /* Disable all interrupts */
 173         ctrl_outl(0, OVERDRIVE_INT_CT);
 174
 175         /* Update interrupt pin mode to use encoded interrupts */
 176         i = ctrl_inw(INTC_ICR);
 177         i &= ~INTC_ICR_IRLM;
 178         ctrl_outw(i, INTC_ICR);
 179
 180         for (i = 0; i < NUM_EXTERNAL_IRQS; i++) {
 181                 if (od_data_table[i].irq_mask != EXTERNAL_IRQ_NOT_IN_USE) {
 182                         make_od_irq(i);
 183                 } else if (i != 15) {   // Cannot use imask on level 15
 184                         make_imask_irq(i);
 185                 }
 186         }
 187
 188         /* Set up the interrupts */
 189         set_od_data(OVERDRIVE_PCI_INTA, OVERDRIVE_PCI_IRQ1);
 190         set_od_data(OVERDRIVE_PCI_INTB, OVERDRIVE_PCI_IRQ2);
 191         set_od_data(OVERDRIVE_AUDIO_INT, OVERDRIVE_ESS_IRQ);
 192 }