arch/arm/mach-exynos4/irq-combiner.c

   1 /* linux/arch/arm/mach-exynos4/irq-combiner.c
   2  *
   3  * Copyright (c) 2010-2011 Samsung Electronics Co., Ltd.
   4  *              http://www.samsung.com
   5  *
   6  * Based on arch/arm/common/gic.c
   7  *
   8  * IRQ COMBINER support
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13 */
  14
  15 #include <linux/io.h>
  16
  17 #include <asm/mach/irq.h>
  18
  19 #define COMBINER_ENABLE_SET     0x0
  20 #define COMBINER_ENABLE_CLEAR   0x4
  21 #define COMBINER_INT_STATUS     0xC
  22
  23 static DEFINE_SPINLOCK(irq_controller_lock);
  24
  25 struct combiner_chip_data {
  26         unsigned int irq_offset;
  27         unsigned int irq_mask;
  28         void __iomem *base;
  29 };
  30
  31 static struct combiner_chip_data combiner_data[MAX_COMBINER_NR];
  32
  33 static inline void __iomem *combiner_base(struct irq_data *data)
  34 {
  35         struct combiner_chip_data *combiner_data =
  36                 irq_data_get_irq_chip_data(data);
  37
  38         return combiner_data->base;
  39 }
  40
  41 static void combiner_mask_irq(struct irq_data *data)
  42 {
  43         u32 mask = 1 << (data->irq % 32);
  44
  45         __raw_writel(mask, combiner_base(data) + COMBINER_ENABLE_CLEAR);
  46 }
  47
  48 static void combiner_unmask_irq(struct irq_data *data)
  49 {
  50         u32 mask = 1 << (data->irq % 32);
  51
  52         __raw_writel(mask, combiner_base(data) + COMBINER_ENABLE_SET);
  53 }
  54
  55 static void combiner_handle_cascade_irq(unsigned int irq, struct irq_desc *desc)
  56 {
  57         struct combiner_chip_data *chip_data = get_irq_data(irq);
  58         struct irq_chip *chip = get_irq_chip(irq);
  59         unsigned int cascade_irq, combiner_irq;
  60         unsigned long status;
  61
  62         /* primary controller ack'ing */
  63         chip->irq_ack(&desc->irq_data);
  64
  65         spin_lock(&irq_controller_lock);
  66         status = __raw_readl(chip_data->base + COMBINER_INT_STATUS);
  67         spin_unlock(&irq_controller_lock);
  68         status &= chip_data->irq_mask;
  69
  70         if (status == 0)
  71                 goto out;
  72
  73         combiner_irq = __ffs(status);
  74
  75         cascade_irq = combiner_irq + (chip_data->irq_offset & ~31);
  76         if (unlikely(cascade_irq >= NR_IRQS))
  77                 do_bad_IRQ(cascade_irq, desc);
  78         else
  79                 generic_handle_irq(cascade_irq);
  80
  81  out:
  82         /* primary controller unmasking */
  83         chip->irq_unmask(&desc->irq_data);
  84 }
  85
  86 static struct irq_chip combiner_chip = {
  87         .name           = "COMBINER",
  88         .irq_mask       = combiner_mask_irq,
  89         .irq_unmask     = combiner_unmask_irq,
  90 };
  91
  92 void __init combiner_cascade_irq(unsigned int combiner_nr, unsigned int irq)
  93 {
  94         if (combiner_nr >= MAX_COMBINER_NR)
  95                 BUG();
  96         if (set_irq_data(irq, &combiner_data[combiner_nr]) != 0)
  97                 BUG();
  98         set_irq_chained_handler(irq, combiner_handle_cascade_irq);
  99 }
 100
 101 void __init combiner_init(unsigned int combiner_nr, void __iomem *base,
 102                           unsigned int irq_start)
 103 {
 104         unsigned int i;
 105
 106         if (combiner_nr >= MAX_COMBINER_NR)
 107                 BUG();
 108
 109         combiner_data[combiner_nr].base = base;
 110         combiner_data[combiner_nr].irq_offset = irq_start;
 111         combiner_data[combiner_nr].irq_mask = 0xff << ((combiner_nr % 4) << 3);
 112
 113         /* Disable all interrupts */
 114
 115         __raw_writel(combiner_data[combiner_nr].irq_mask,
 116                      base + COMBINER_ENABLE_CLEAR);
 117
 118         /* Setup the Linux IRQ subsystem */
 119
 120         for (i = irq_start; i < combiner_data[combiner_nr].irq_offset
 121                                 + MAX_IRQ_IN_COMBINER; i++) {
 122                 set_irq_chip(i, &combiner_chip);
 123                 set_irq_chip_data(i, &combiner_data[combiner_nr]);
 124                 set_irq_handler(i, handle_level_irq);
 125                 set_irq_flags(i, IRQF_VALID | IRQF_PROBE);
 126         }
 127 }