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   1 /*
   2  * External interrupt handling for AT32AP CPUs
   3  *
   4  * Copyright (C) 2006 Atmel Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/errno.h>
  12 #include <linux/init.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/irq.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/random.h>
  17
  18 #include <asm/io.h>
  19
  20 /* EIC register offsets */
  21 #define EIC_IER                                 0x0000
  22 #define EIC_IDR                                 0x0004
  23 #define EIC_IMR                                 0x0008
  24 #define EIC_ISR                                 0x000c
  25 #define EIC_ICR                                 0x0010
  26 #define EIC_MODE                                0x0014
  27 #define EIC_EDGE                                0x0018
  28 #define EIC_LEVEL                               0x001c
  29 #define EIC_TEST                                0x0020
  30 #define EIC_NMIC                                0x0024
  31
  32 /* Bitfields in TEST */
  33 #define EIC_TESTEN_OFFSET                       31
  34 #define EIC_TESTEN_SIZE                         1
  35
  36 /* Bitfields in NMIC */
  37 #define EIC_EN_OFFSET                           0
  38 #define EIC_EN_SIZE                             1
  39
  40 /* Bit manipulation macros */
  41 #define EIC_BIT(name)                                   \
  42         (1 << EIC_##name##_OFFSET)
  43 #define EIC_BF(name,value)                              \
  44         (((value) & ((1 << EIC_##name##_SIZE) - 1))     \
  45          << EIC_##name##_OFFSET)
  46 #define EIC_BFEXT(name,value)                           \
  47         (((value) >> EIC_##name##_OFFSET)               \
  48          & ((1 << EIC_##name##_SIZE) - 1))
  49 #define EIC_BFINS(name,value,old)                       \
  50         (((old) & ~(((1 << EIC_##name##_SIZE) - 1)      \
  51                     << EIC_##name##_OFFSET))            \
  52          | EIC_BF(name,value))
  53
  54 /* Register access macros */
  55 #define eic_readl(port,reg)                             \
  56         __raw_readl((port)->regs + EIC_##reg)
  57 #define eic_writel(port,reg,value)                      \
  58         __raw_writel((value), (port)->regs + EIC_##reg)
  59
  60 struct eic {
  61         void __iomem *regs;
  62         struct irq_chip *chip;
  63         unsigned int first_irq;
  64 };
  65
  66 static void eic_ack_irq(unsigned int irq)
  67 {
  68         struct eic *eic = get_irq_chip_data(irq);
  69         eic_writel(eic, ICR, 1 << (irq - eic->first_irq));
  70 }
  71
  72 static void eic_mask_irq(unsigned int irq)
  73 {
  74         struct eic *eic = get_irq_chip_data(irq);
  75         eic_writel(eic, IDR, 1 << (irq - eic->first_irq));
  76 }
  77
  78 static void eic_mask_ack_irq(unsigned int irq)
  79 {
  80         struct eic *eic = get_irq_chip_data(irq);
  81         eic_writel(eic, ICR, 1 << (irq - eic->first_irq));
  82         eic_writel(eic, IDR, 1 << (irq - eic->first_irq));
  83 }
  84
  85 static void eic_unmask_irq(unsigned int irq)
  86 {
  87         struct eic *eic = get_irq_chip_data(irq);
  88         eic_writel(eic, IER, 1 << (irq - eic->first_irq));
  89 }
  90
  91 static int eic_set_irq_type(unsigned int irq, unsigned int flow_type)
  92 {
  93         struct eic *eic = get_irq_chip_data(irq);
  94         struct irq_desc *desc;
  95         unsigned int i = irq - eic->first_irq;
  96         u32 mode, edge, level;
  97         int ret = 0;
  98
  99         flow_type &= IRQ_TYPE_SENSE_MASK;
 100         if (flow_type == IRQ_TYPE_NONE)
 101                 flow_type = IRQ_TYPE_LEVEL_LOW;
 102
 103         desc = &irq_desc[irq];
 104
 105         mode = eic_readl(eic, MODE);
 106         edge = eic_readl(eic, EDGE);
 107         level = eic_readl(eic, LEVEL);
 108
 109         switch (flow_type) {
 110         case IRQ_TYPE_LEVEL_LOW:
 111                 mode |= 1 << i;
 112                 level &= ~(1 << i);
 113                 break;
 114         case IRQ_TYPE_LEVEL_HIGH:
 115                 mode |= 1 << i;
 116                 level |= 1 << i;
 117                 break;
 118         case IRQ_TYPE_EDGE_RISING:
 119                 mode &= ~(1 << i);
 120                 edge |= 1 << i;
 121                 break;
 122         case IRQ_TYPE_EDGE_FALLING:
 123                 mode &= ~(1 << i);
 124                 edge &= ~(1 << i);
 125                 break;
 126         default:
 127                 ret = -EINVAL;
 128                 break;
 129         }
 130
 131         if (ret == 0) {
 132                 eic_writel(eic, MODE, mode);
 133                 eic_writel(eic, EDGE, edge);
 134                 eic_writel(eic, LEVEL, level);
 135
 136                 if (flow_type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
 137                         flow_type |= IRQ_LEVEL;
 138                 desc->status &= ~(IRQ_TYPE_SENSE_MASK | IRQ_LEVEL);
 139                 desc->status |= flow_type;
 140         }
 141
 142         return ret;
 143 }
 144
 145 static struct irq_chip eic_chip = {
 146         .name           = "eic",
 147         .ack            = eic_ack_irq,
 148         .mask           = eic_mask_irq,
 149         .mask_ack       = eic_mask_ack_irq,
 150         .unmask         = eic_unmask_irq,
 151         .set_type       = eic_set_irq_type,
 152 };
 153
 154 static void demux_eic_irq(unsigned int irq, struct irq_desc *desc)
 155 {
 156         struct eic *eic = desc->handler_data;
 157         struct irq_desc *ext_desc;
 158         unsigned long status, pending;
 159         unsigned int i, ext_irq;
 160
 161         status = eic_readl(eic, ISR);
 162         pending = status & eic_readl(eic, IMR);
 163
 164         while (pending) {
 165                 i = fls(pending) - 1;
 166                 pending &= ~(1 << i);
 167
 168                 ext_irq = i + eic->first_irq;
 169                 ext_desc = irq_desc + ext_irq;
 170                 if (ext_desc->status & IRQ_LEVEL)
 171                         handle_level_irq(ext_irq, ext_desc);
 172                 else
 173                         handle_edge_irq(ext_irq, ext_desc);
 174         }
 175 }
 176
 177 static int __init eic_probe(struct platform_device *pdev)
 178 {
 179         struct eic *eic;
 180         struct resource *regs;
 181         unsigned int i;
 182         unsigned int nr_irqs;
 183         unsigned int int_irq;
 184         int ret;
 185         u32 pattern;
 186
 187         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 188         int_irq = platform_get_irq(pdev, 0);
 189         if (!regs || !int_irq) {
 190                 dev_dbg(&pdev->dev, "missing regs and/or irq resource\n");
 191                 return -ENXIO;
 192         }
 193
 194         ret = -ENOMEM;
 195         eic = kzalloc(sizeof(struct eic), GFP_KERNEL);
 196         if (!eic) {
 197                 dev_dbg(&pdev->dev, "no memory for eic structure\n");
 198                 goto err_kzalloc;
 199         }
 200
 201         eic->first_irq = EIM_IRQ_BASE + 32 * pdev->id;
 202         eic->regs = ioremap(regs->start, regs->end - regs->start + 1);
 203         if (!eic->regs) {
 204                 dev_dbg(&pdev->dev, "failed to map regs\n");
 205                 goto err_ioremap;
 206         }
 207
 208         /*
 209          * Find out how many interrupt lines that are actually
 210          * implemented in hardware.
 211          */
 212         eic_writel(eic, IDR, ~0UL);
 213         eic_writel(eic, MODE, ~0UL);
 214         pattern = eic_readl(eic, MODE);
 215         nr_irqs = fls(pattern);
 216
 217         /* Trigger on falling edge unless overridden by driver */
 218         eic_writel(eic, MODE, 0UL);
 219         eic_writel(eic, EDGE, 0UL);
 220
 221         eic->chip = &eic_chip;
 222
 223         for (i = 0; i < nr_irqs; i++) {
 224                 /* NOTE the handler we set here is ignored by the demux */
 225                 set_irq_chip_and_handler(eic->first_irq + i, &eic_chip,
 226                                          handle_level_irq);
 227                 set_irq_chip_data(eic->first_irq + i, eic);
 228         }
 229
 230         set_irq_chained_handler(int_irq, demux_eic_irq);
 231         set_irq_data(int_irq, eic);
 232
 233         dev_info(&pdev->dev,
 234                  "External Interrupt Controller at 0x%p, IRQ %u\n",
 235                  eic->regs, int_irq);
 236         dev_info(&pdev->dev,
 237                  "Handling %u external IRQs, starting with IRQ %u\n",
 238                  nr_irqs, eic->first_irq);
 239
 240         return 0;
 241
 242 err_ioremap:
 243         kfree(eic);
 244 err_kzalloc:
 245         return ret;
 246 }
 247
 248 static struct platform_driver eic_driver = {
 249         .driver = {
 250                 .name = "at32_eic",
 251         },
 252 };
 253
 254 static int __init eic_init(void)
 255 {
 256         return platform_driver_probe(&eic_driver, eic_probe);
 257 }
 258 arch_initcall(eic_init);