arch/powerpc/platforms/85xx/socrates_fpga_pic.c

   1 /*
   2  *  Copyright (C) 2008 Ilya Yanok, Emcraft Systems
   3  *
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  */
  10
  11 #include <linux/irq.h>
  12 #include <linux/of_platform.h>
  13 #include <linux/io.h>
  14
  15 /*
  16  * The FPGA supports 9 interrupt sources, which can be routed to 3
  17  * interrupt request lines of the MPIC. The line to be used can be
  18  * specified through the third cell of FDT property  "interrupts".
  19  */
  20
  21 #define SOCRATES_FPGA_NUM_IRQS  9
  22
  23 #define FPGA_PIC_IRQCFG         (0x0)
  24 #define FPGA_PIC_IRQMASK(n)     (0x4 + 0x4 * (n))
  25
  26 #define SOCRATES_FPGA_IRQ_MASK  ((1 << SOCRATES_FPGA_NUM_IRQS) - 1)
  27
  28 struct socrates_fpga_irq_info {
  29         unsigned int irq_line;
  30         int type;
  31 };
  32
  33 /*
  34  * Interrupt routing and type table
  35  *
  36  * IRQ_TYPE_NONE means the interrupt type is configurable,
  37  * otherwise it's fixed to the specified value.
  38  */
  39 static struct socrates_fpga_irq_info fpga_irqs[SOCRATES_FPGA_NUM_IRQS] = {
  40         [0] = {0, IRQ_TYPE_NONE},
  41         [1] = {0, IRQ_TYPE_LEVEL_HIGH},
  42         [2] = {0, IRQ_TYPE_LEVEL_LOW},
  43         [3] = {0, IRQ_TYPE_NONE},
  44         [4] = {0, IRQ_TYPE_NONE},
  45         [5] = {0, IRQ_TYPE_NONE},
  46         [6] = {0, IRQ_TYPE_NONE},
  47         [7] = {0, IRQ_TYPE_NONE},
  48         [8] = {0, IRQ_TYPE_LEVEL_HIGH},
  49 };
  50
  51 #define socrates_fpga_irq_to_hw(virq)    ((unsigned int)irq_map[virq].hwirq)
  52
  53 static DEFINE_SPINLOCK(socrates_fpga_pic_lock);
  54
  55 static void __iomem *socrates_fpga_pic_iobase;
  56 static struct irq_host *socrates_fpga_pic_irq_host;
  57 static unsigned int socrates_fpga_irqs[3];
  58
  59 static inline uint32_t socrates_fpga_pic_read(int reg)
  60 {
  61         return in_be32(socrates_fpga_pic_iobase + reg);
  62 }
  63
  64 static inline void socrates_fpga_pic_write(int reg, uint32_t val)
  65 {
  66         out_be32(socrates_fpga_pic_iobase + reg, val);
  67 }
  68
  69 static inline unsigned int socrates_fpga_pic_get_irq(unsigned int irq)
  70 {
  71         uint32_t cause;
  72         unsigned long flags;
  73         int i;
  74
  75         /* Check irq line routed to the MPIC */
  76         for (i = 0; i < 3; i++) {
  77                 if (irq == socrates_fpga_irqs[i])
  78                         break;
  79         }
  80         if (i == 3)
  81                 return NO_IRQ;
  82
  83         spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
  84         cause = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(i));
  85         spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
  86         for (i = SOCRATES_FPGA_NUM_IRQS - 1; i >= 0; i--) {
  87                 if (cause >> (i + 16))
  88                         break;
  89         }
  90         return irq_linear_revmap(socrates_fpga_pic_irq_host,
  91                         (irq_hw_number_t)i);
  92 }
  93
  94 void socrates_fpga_pic_cascade(unsigned int irq, struct irq_desc *desc)
  95 {
  96         unsigned int cascade_irq;
  97
  98         /*
  99          * See if we actually have an interrupt, call generic handling code if
 100          * we do.
 101          */
 102         cascade_irq = socrates_fpga_pic_get_irq(irq);
 103
 104         if (cascade_irq != NO_IRQ)
 105                 generic_handle_irq(cascade_irq);
 106         desc->chip->eoi(irq);
 107
 108 }
 109
 110 static void socrates_fpga_pic_ack(unsigned int virq)
 111 {
 112         unsigned long flags;
 113         unsigned int hwirq, irq_line;
 114         uint32_t mask;
 115
 116         hwirq = socrates_fpga_irq_to_hw(virq);
 117
 118         irq_line = fpga_irqs[hwirq].irq_line;
 119         spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 120         mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
 121                 & SOCRATES_FPGA_IRQ_MASK;
 122         mask |= (1 << (hwirq + 16));
 123         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
 124         spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 125 }
 126
 127 static void socrates_fpga_pic_mask(unsigned int virq)
 128 {
 129         unsigned long flags;
 130         unsigned int hwirq;
 131         int irq_line;
 132         u32 mask;
 133
 134         hwirq = socrates_fpga_irq_to_hw(virq);
 135
 136         irq_line = fpga_irqs[hwirq].irq_line;
 137         spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 138         mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
 139                 & SOCRATES_FPGA_IRQ_MASK;
 140         mask &= ~(1 << hwirq);
 141         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
 142         spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 143 }
 144
 145 static void socrates_fpga_pic_mask_ack(unsigned int virq)
 146 {
 147         unsigned long flags;
 148         unsigned int hwirq;
 149         int irq_line;
 150         u32 mask;
 151
 152         hwirq = socrates_fpga_irq_to_hw(virq);
 153
 154         irq_line = fpga_irqs[hwirq].irq_line;
 155         spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 156         mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
 157                 & SOCRATES_FPGA_IRQ_MASK;
 158         mask &= ~(1 << hwirq);
 159         mask |= (1 << (hwirq + 16));
 160         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
 161         spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 162 }
 163
 164 static void socrates_fpga_pic_unmask(unsigned int virq)
 165 {
 166         unsigned long flags;
 167         unsigned int hwirq;
 168         int irq_line;
 169         u32 mask;
 170
 171         hwirq = socrates_fpga_irq_to_hw(virq);
 172
 173         irq_line = fpga_irqs[hwirq].irq_line;
 174         spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 175         mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
 176                 & SOCRATES_FPGA_IRQ_MASK;
 177         mask |= (1 << hwirq);
 178         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
 179         spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 180 }
 181
 182 static void socrates_fpga_pic_eoi(unsigned int virq)
 183 {
 184         unsigned long flags;
 185         unsigned int hwirq;
 186         int irq_line;
 187         u32 mask;
 188
 189         hwirq = socrates_fpga_irq_to_hw(virq);
 190
 191         irq_line = fpga_irqs[hwirq].irq_line;
 192         spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 193         mask = socrates_fpga_pic_read(FPGA_PIC_IRQMASK(irq_line))
 194                 & SOCRATES_FPGA_IRQ_MASK;
 195         mask |= (1 << (hwirq + 16));
 196         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(irq_line), mask);
 197         spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 198 }
 199
 200 static int socrates_fpga_pic_set_type(unsigned int virq,
 201                 unsigned int flow_type)
 202 {
 203         unsigned long flags;
 204         unsigned int hwirq;
 205         int polarity;
 206         u32 mask;
 207
 208         hwirq = socrates_fpga_irq_to_hw(virq);
 209
 210         if (fpga_irqs[hwirq].type != IRQ_TYPE_NONE)
 211                 return -EINVAL;
 212
 213         switch (flow_type & IRQ_TYPE_SENSE_MASK) {
 214         case IRQ_TYPE_LEVEL_HIGH:
 215                 polarity = 1;
 216                 break;
 217         case IRQ_TYPE_LEVEL_LOW:
 218                 polarity = 0;
 219                 break;
 220         default:
 221                 return -EINVAL;
 222         }
 223         spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 224         mask = socrates_fpga_pic_read(FPGA_PIC_IRQCFG);
 225         if (polarity)
 226                 mask |= (1 << hwirq);
 227         else
 228                 mask &= ~(1 << hwirq);
 229         socrates_fpga_pic_write(FPGA_PIC_IRQCFG, mask);
 230         spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 231         return 0;
 232 }
 233
 234 static struct irq_chip socrates_fpga_pic_chip = {
 235         .typename       = " FPGA-PIC ",
 236         .ack            = socrates_fpga_pic_ack,
 237         .mask           = socrates_fpga_pic_mask,
 238         .mask_ack       = socrates_fpga_pic_mask_ack,
 239         .unmask         = socrates_fpga_pic_unmask,
 240         .eoi            = socrates_fpga_pic_eoi,
 241         .set_type       = socrates_fpga_pic_set_type,
 242 };
 243
 244 static int socrates_fpga_pic_host_map(struct irq_host *h, unsigned int virq,
 245                 irq_hw_number_t hwirq)
 246 {
 247         /* All interrupts are LEVEL sensitive */
 248         get_irq_desc(virq)->status |= IRQ_LEVEL;
 249         set_irq_chip_and_handler(virq, &socrates_fpga_pic_chip,
 250                         handle_fasteoi_irq);
 251
 252         return 0;
 253 }
 254
 255 static int socrates_fpga_pic_host_xlate(struct irq_host *h,
 256                 struct device_node *ct, u32 *intspec, unsigned int intsize,
 257                 irq_hw_number_t *out_hwirq, unsigned int *out_flags)
 258 {
 259         struct socrates_fpga_irq_info *fpga_irq = &fpga_irqs[intspec[0]];
 260
 261         *out_hwirq = intspec[0];
 262         if  (fpga_irq->type == IRQ_TYPE_NONE) {
 263                 /* type is configurable */
 264                 if (intspec[1] != IRQ_TYPE_LEVEL_LOW &&
 265                     intspec[1] != IRQ_TYPE_LEVEL_HIGH) {
 266                         pr_warning("FPGA PIC: invalid irq type, "
 267                                    "setting default active low\n");
 268                         *out_flags = IRQ_TYPE_LEVEL_LOW;
 269                 } else {
 270                         *out_flags = intspec[1];
 271                 }
 272         } else {
 273                 /* type is fixed */
 274                 *out_flags = fpga_irq->type;
 275         }
 276
 277         /* Use specified interrupt routing */
 278         if (intspec[2] <= 2)
 279                 fpga_irq->irq_line = intspec[2];
 280         else
 281                 pr_warning("FPGA PIC: invalid irq routing\n");
 282
 283         return 0;
 284 }
 285
 286 static struct irq_host_ops socrates_fpga_pic_host_ops = {
 287         .map    = socrates_fpga_pic_host_map,
 288         .xlate  = socrates_fpga_pic_host_xlate,
 289 };
 290
 291 void socrates_fpga_pic_init(struct device_node *pic)
 292 {
 293         unsigned long flags;
 294         int i;
 295
 296         /* Setup an irq_host structure */
 297         socrates_fpga_pic_irq_host = irq_alloc_host(pic, IRQ_HOST_MAP_LINEAR,
 298                         SOCRATES_FPGA_NUM_IRQS, &socrates_fpga_pic_host_ops,
 299                         SOCRATES_FPGA_NUM_IRQS);
 300         if (socrates_fpga_pic_irq_host == NULL) {
 301                 pr_err("FPGA PIC: Unable to allocate host\n");
 302                 return;
 303         }
 304
 305         for (i = 0; i < 3; i++) {
 306                 socrates_fpga_irqs[i] = irq_of_parse_and_map(pic, i);
 307                 if (socrates_fpga_irqs[i] == NO_IRQ) {
 308                         pr_warning("FPGA PIC: can't get irq%d.\n", i);
 309                         continue;
 310                 }
 311                 set_irq_chained_handler(socrates_fpga_irqs[i],
 312                                 socrates_fpga_pic_cascade);
 313         }
 314
 315         socrates_fpga_pic_iobase = of_iomap(pic, 0);
 316
 317         spin_lock_irqsave(&socrates_fpga_pic_lock, flags);
 318         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(0),
 319                         SOCRATES_FPGA_IRQ_MASK << 16);
 320         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(1),
 321                         SOCRATES_FPGA_IRQ_MASK << 16);
 322         socrates_fpga_pic_write(FPGA_PIC_IRQMASK(2),
 323                         SOCRATES_FPGA_IRQ_MASK << 16);
 324         spin_unlock_irqrestore(&socrates_fpga_pic_lock, flags);
 325
 326         pr_info("FPGA PIC: Setting up Socrates FPGA PIC\n");
 327 }