arch/arm/mach-davinci/cp_intc.c

   1 /*
   2  * TI Common Platform Interrupt Controller (cp_intc) driver
   3  *
   4  * Author: Steve Chen <schen@mvista.com>
   5  * Copyright (C) 2008-2009, MontaVista Software, Inc. <source@mvista.com>
   6  *
   7  * This file is licensed under the terms of the GNU General Public License
   8  * version 2. This program is licensed "as is" without any warranty of any
   9  * kind, whether express or implied.
  10  */
  11
  12 #include <linux/init.h>
  13 #include <linux/irq.h>
  14 #include <linux/io.h>
  15
  16 #include <mach/common.h>
  17 #include <mach/cp_intc.h>
  18
  19 static inline unsigned int cp_intc_read(unsigned offset)
  20 {
  21         return __raw_readl(davinci_intc_base + offset);
  22 }
  23
  24 static inline void cp_intc_write(unsigned long value, unsigned offset)
  25 {
  26         __raw_writel(value, davinci_intc_base + offset);
  27 }
  28
  29 static void cp_intc_ack_irq(struct irq_data *d)
  30 {
  31         cp_intc_write(d->irq, CP_INTC_SYS_STAT_IDX_CLR);
  32 }
  33
  34 /* Disable interrupt */
  35 static void cp_intc_mask_irq(struct irq_data *d)
  36 {
  37         /* XXX don't know why we need to disable nIRQ here... */
  38         cp_intc_write(1, CP_INTC_HOST_ENABLE_IDX_CLR);
  39         cp_intc_write(d->irq, CP_INTC_SYS_ENABLE_IDX_CLR);
  40         cp_intc_write(1, CP_INTC_HOST_ENABLE_IDX_SET);
  41 }
  42
  43 /* Enable interrupt */
  44 static void cp_intc_unmask_irq(struct irq_data *d)
  45 {
  46         cp_intc_write(d->irq, CP_INTC_SYS_ENABLE_IDX_SET);
  47 }
  48
  49 static int cp_intc_set_irq_type(struct irq_data *d, unsigned int flow_type)
  50 {
  51         unsigned reg            = BIT_WORD(d->irq);
  52         unsigned mask           = BIT_MASK(d->irq);
  53         unsigned polarity       = cp_intc_read(CP_INTC_SYS_POLARITY(reg));
  54         unsigned type           = cp_intc_read(CP_INTC_SYS_TYPE(reg));
  55
  56         switch (flow_type) {
  57         case IRQ_TYPE_EDGE_RISING:
  58                 polarity |= mask;
  59                 type |= mask;
  60                 break;
  61         case IRQ_TYPE_EDGE_FALLING:
  62                 polarity &= ~mask;
  63                 type |= mask;
  64                 break;
  65         case IRQ_TYPE_LEVEL_HIGH:
  66                 polarity |= mask;
  67                 type &= ~mask;
  68                 break;
  69         case IRQ_TYPE_LEVEL_LOW:
  70                 polarity &= ~mask;
  71                 type &= ~mask;
  72                 break;
  73         default:
  74                 return -EINVAL;
  75         }
  76
  77         cp_intc_write(polarity, CP_INTC_SYS_POLARITY(reg));
  78         cp_intc_write(type, CP_INTC_SYS_TYPE(reg));
  79
  80         return 0;
  81 }
  82
  83 /*
  84  * Faking this allows us to to work with suspend functions of
  85  * generic drivers which call {enable|disable}_irq_wake for
  86  * wake up interrupt sources (eg RTC on DA850).
  87  */
  88 static int cp_intc_set_wake(struct irq_data *d, unsigned int on)
  89 {
  90         return 0;
  91 }
  92
  93 static struct irq_chip cp_intc_irq_chip = {
  94         .name           = "cp_intc",
  95         .irq_ack        = cp_intc_ack_irq,
  96         .irq_mask       = cp_intc_mask_irq,
  97         .irq_unmask     = cp_intc_unmask_irq,
  98         .irq_set_type   = cp_intc_set_irq_type,
  99         .irq_set_wake   = cp_intc_set_wake,
 100 };
 101
 102 void __init cp_intc_init(void)
 103 {
 104         unsigned long num_irq   = davinci_soc_info.intc_irq_num;
 105         u8 *irq_prio            = davinci_soc_info.intc_irq_prios;
 106         u32 *host_map           = davinci_soc_info.intc_host_map;
 107         unsigned num_reg        = BITS_TO_LONGS(num_irq);
 108         int i;
 109
 110         davinci_intc_type = DAVINCI_INTC_TYPE_CP_INTC;
 111         davinci_intc_base = ioremap(davinci_soc_info.intc_base, SZ_8K);
 112         if (WARN_ON(!davinci_intc_base))
 113                 return;
 114
 115         cp_intc_write(0, CP_INTC_GLOBAL_ENABLE);
 116
 117         /* Disable all host interrupts */
 118         cp_intc_write(0, CP_INTC_HOST_ENABLE(0));
 119
 120         /* Disable system interrupts */
 121         for (i = 0; i < num_reg; i++)
 122                 cp_intc_write(~0, CP_INTC_SYS_ENABLE_CLR(i));
 123
 124         /* Set to normal mode, no nesting, no priority hold */
 125         cp_intc_write(0, CP_INTC_CTRL);
 126         cp_intc_write(0, CP_INTC_HOST_CTRL);
 127
 128         /* Clear system interrupt status */
 129         for (i = 0; i < num_reg; i++)
 130                 cp_intc_write(~0, CP_INTC_SYS_STAT_CLR(i));
 131
 132         /* Enable nIRQ (what about nFIQ?) */
 133         cp_intc_write(1, CP_INTC_HOST_ENABLE_IDX_SET);
 134
 135         /*
 136          * Priority is determined by host channel: lower channel number has
 137          * higher priority i.e. channel 0 has highest priority and channel 31
 138          * had the lowest priority.
 139          */
 140         num_reg = (num_irq + 3) >> 2;   /* 4 channels per register */
 141         if (irq_prio) {
 142                 unsigned j, k;
 143                 u32 val;
 144
 145                 for (k = i = 0; i < num_reg; i++) {
 146                         for (val = j = 0; j < 4; j++, k++) {
 147                                 val >>= 8;
 148                                 if (k < num_irq)
 149                                         val |= irq_prio[k] << 24;
 150                         }
 151
 152                         cp_intc_write(val, CP_INTC_CHAN_MAP(i));
 153                 }
 154         } else  {
 155                 /*
 156                  * Default everything to channel 15 if priority not specified.
 157                  * Note that channel 0-1 are mapped to nFIQ and channels 2-31
 158                  * are mapped to nIRQ.
 159                  */
 160                 for (i = 0; i < num_reg; i++)
 161                         cp_intc_write(0x0f0f0f0f, CP_INTC_CHAN_MAP(i));
 162         }
 163
 164         if (host_map)
 165                 for (i = 0; host_map[i] != -1; i++)
 166                         cp_intc_write(host_map[i], CP_INTC_HOST_MAP(i));
 167
 168         /* Set up genirq dispatching for cp_intc */
 169         for (i = 0; i < num_irq; i++) {
 170                 irq_set_chip(i, &cp_intc_irq_chip);
 171                 set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
 172                 irq_set_handler(i, handle_edge_irq);
 173         }
 174
 175         /* Enable global interrupt */
 176         cp_intc_write(1, CP_INTC_GLOBAL_ENABLE);
 177 }