drivers/of/irq.c

   1 /*
   2  *  Derived from arch/i386/kernel/irq.c
   3  *    Copyright (C) 1992 Linus Torvalds
   4  *  Adapted from arch/i386 by Gary Thomas
   5  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
   6  *  Updated and modified by Cort Dougan <cort@fsmlabs.com>
   7  *    Copyright (C) 1996-2001 Cort Dougan
   8  *  Adapted for Power Macintosh by Paul Mackerras
   9  *    Copyright (C) 1996 Paul Mackerras (paulus@cs.anu.edu.au)
  10  *
  11  * This program is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU General Public License
  13  * as published by the Free Software Foundation; either version
  14  * 2 of the License, or (at your option) any later version.
  15  *
  16  * This file contains the code used to make IRQ descriptions in the
  17  * device tree to actual irq numbers on an interrupt controller
  18  * driver.
  19  */
  20
  21 #include <linux/errno.h>
  22 #include <linux/module.h>
  23 #include <linux/of.h>
  24 #include <linux/of_irq.h>
  25 #include <linux/string.h>
  26
  27 /* For archs that don't support NO_IRQ (such as x86), provide a dummy value */
  28 #ifndef NO_IRQ
  29 #define NO_IRQ 0
  30 #endif
  31
  32 /**
  33  * irq_of_parse_and_map - Parse and map an interrupt into linux virq space
  34  * @device: Device node of the device whose interrupt is to be mapped
  35  * @index: Index of the interrupt to map
  36  *
  37  * This function is a wrapper that chains of_irq_map_one() and
  38  * irq_create_of_mapping() to make things easier to callers
  39  */
  40 unsigned int irq_of_parse_and_map(struct device_node *dev, int index)
  41 {
  42         struct of_irq oirq;
  43
  44         if (of_irq_map_one(dev, index, &oirq))
  45                 return NO_IRQ;
  46
  47         return irq_create_of_mapping(oirq.controller, oirq.specifier,
  48                                      oirq.size);
  49 }
  50 EXPORT_SYMBOL_GPL(irq_of_parse_and_map);
  51
  52 /**
  53  * of_irq_find_parent - Given a device node, find its interrupt parent node
  54  * @child: pointer to device node
  55  *
  56  * Returns a pointer to the interrupt parent node, or NULL if the interrupt
  57  * parent could not be determined.
  58  */
  59 static struct device_node *of_irq_find_parent(struct device_node *child)
  60 {
  61         struct device_node *p;
  62         const __be32 *parp;
  63
  64         if (!of_node_get(child))
  65                 return NULL;
  66
  67         do {
  68                 parp = of_get_property(child, "interrupt-parent", NULL);
  69                 if (parp == NULL)
  70                         p = of_get_parent(child);
  71                 else {
  72                         if (of_irq_workarounds & OF_IMAP_NO_PHANDLE)
  73                                 p = of_node_get(of_irq_dflt_pic);
  74                         else
  75                                 p = of_find_node_by_phandle(be32_to_cpup(parp));
  76                 }
  77                 of_node_put(child);
  78                 child = p;
  79         } while (p && of_get_property(p, "#interrupt-cells", NULL) == NULL);
  80
  81         return p;
  82 }
  83
  84 /**
  85  * of_irq_map_raw - Low level interrupt tree parsing
  86  * @parent:     the device interrupt parent
  87  * @intspec:    interrupt specifier ("interrupts" property of the device)
  88  * @ointsize:   size of the passed in interrupt specifier
  89  * @addr:       address specifier (start of "reg" property of the device)
  90  * @out_irq:    structure of_irq filled by this function
  91  *
  92  * Returns 0 on success and a negative number on error
  93  *
  94  * This function is a low-level interrupt tree walking function. It
  95  * can be used to do a partial walk with synthetized reg and interrupts
  96  * properties, for example when resolving PCI interrupts when no device
  97  * node exist for the parent.
  98  */
  99 int of_irq_map_raw(struct device_node *parent, const __be32 *intspec,
 100                    u32 ointsize, const __be32 *addr, struct of_irq *out_irq)
 101 {
 102         struct device_node *ipar, *tnode, *old = NULL, *newpar = NULL;
 103         const __be32 *tmp, *imap, *imask;
 104         u32 intsize = 1, addrsize, newintsize = 0, newaddrsize = 0;
 105         int imaplen, match, i;
 106
 107         pr_debug("of_irq_map_raw: par=%s,intspec=[0x%08x 0x%08x...],ointsize=%d\n",
 108                  parent->full_name, be32_to_cpup(intspec),
 109                  be32_to_cpup(intspec + 1), ointsize);
 110
 111         ipar = of_node_get(parent);
 112
 113         /* First get the #interrupt-cells property of the current cursor
 114          * that tells us how to interpret the passed-in intspec. If there
 115          * is none, we are nice and just walk up the tree
 116          */
 117         do {
 118                 tmp = of_get_property(ipar, "#interrupt-cells", NULL);
 119                 if (tmp != NULL) {
 120                         intsize = be32_to_cpu(*tmp);
 121                         break;
 122                 }
 123                 tnode = ipar;
 124                 ipar = of_irq_find_parent(ipar);
 125                 of_node_put(tnode);
 126         } while (ipar);
 127         if (ipar == NULL) {
 128                 pr_debug(" -> no parent found !\n");
 129                 goto fail;
 130         }
 131
 132         pr_debug("of_irq_map_raw: ipar=%s, size=%d\n", ipar->full_name, intsize);
 133
 134         if (ointsize != intsize)
 135                 return -EINVAL;
 136
 137         /* Look for this #address-cells. We have to implement the old linux
 138          * trick of looking for the parent here as some device-trees rely on it
 139          */
 140         old = of_node_get(ipar);
 141         do {
 142                 tmp = of_get_property(old, "#address-cells", NULL);
 143                 tnode = of_get_parent(old);
 144                 of_node_put(old);
 145                 old = tnode;
 146         } while (old && tmp == NULL);
 147         of_node_put(old);
 148         old = NULL;
 149         addrsize = (tmp == NULL) ? 2 : be32_to_cpu(*tmp);
 150
 151         pr_debug(" -> addrsize=%d\n", addrsize);
 152
 153         /* Now start the actual "proper" walk of the interrupt tree */
 154         while (ipar != NULL) {
 155                 /* Now check if cursor is an interrupt-controller and if it is
 156                  * then we are done
 157                  */
 158                 if (of_get_property(ipar, "interrupt-controller", NULL) !=
 159                                 NULL) {
 160                         pr_debug(" -> got it !\n");
 161                         for (i = 0; i < intsize; i++)
 162                                 out_irq->specifier[i] =
 163                                                 of_read_number(intspec +i, 1);
 164                         out_irq->size = intsize;
 165                         out_irq->controller = ipar;
 166                         of_node_put(old);
 167                         return 0;
 168                 }
 169
 170                 /* Now look for an interrupt-map */
 171                 imap = of_get_property(ipar, "interrupt-map", &imaplen);
 172                 /* No interrupt map, check for an interrupt parent */
 173                 if (imap == NULL) {
 174                         pr_debug(" -> no map, getting parent\n");
 175                         newpar = of_irq_find_parent(ipar);
 176                         goto skiplevel;
 177                 }
 178                 imaplen /= sizeof(u32);
 179
 180                 /* Look for a mask */
 181                 imask = of_get_property(ipar, "interrupt-map-mask", NULL);
 182
 183                 /* If we were passed no "reg" property and we attempt to parse
 184                  * an interrupt-map, then #address-cells must be 0.
 185                  * Fail if it's not.
 186                  */
 187                 if (addr == NULL && addrsize != 0) {
 188                         pr_debug(" -> no reg passed in when needed !\n");
 189                         goto fail;
 190                 }
 191
 192                 /* Parse interrupt-map */
 193                 match = 0;
 194                 while (imaplen > (addrsize + intsize + 1) && !match) {
 195                         /* Compare specifiers */
 196                         match = 1;
 197                         for (i = 0; i < addrsize && match; ++i) {
 198                                 u32 mask = imask ? imask[i] : 0xffffffffu;
 199                                 match = ((addr[i] ^ imap[i]) & mask) == 0;
 200                         }
 201                         for (; i < (addrsize + intsize) && match; ++i) {
 202                                 u32 mask = imask ? imask[i] : 0xffffffffu;
 203                                 match =
 204                                    ((intspec[i-addrsize] ^ imap[i]) & mask) == 0;
 205                         }
 206                         imap += addrsize + intsize;
 207                         imaplen -= addrsize + intsize;
 208
 209                         pr_debug(" -> match=%d (imaplen=%d)\n", match, imaplen);
 210
 211                         /* Get the interrupt parent */
 212                         if (of_irq_workarounds & OF_IMAP_NO_PHANDLE)
 213                                 newpar = of_node_get(of_irq_dflt_pic);
 214                         else
 215                                 newpar = of_find_node_by_phandle(be32_to_cpup(imap));
 216                         imap++;
 217                         --imaplen;
 218
 219                         /* Check if not found */
 220                         if (newpar == NULL) {
 221                                 pr_debug(" -> imap parent not found !\n");
 222                                 goto fail;
 223                         }
 224
 225                         /* Get #interrupt-cells and #address-cells of new
 226                          * parent
 227                          */
 228                         tmp = of_get_property(newpar, "#interrupt-cells", NULL);
 229                         if (tmp == NULL) {
 230                                 pr_debug(" -> parent lacks #interrupt-cells!\n");
 231                                 goto fail;
 232                         }
 233                         newintsize = be32_to_cpu(*tmp);
 234                         tmp = of_get_property(newpar, "#address-cells", NULL);
 235                         newaddrsize = (tmp == NULL) ? 0 : be32_to_cpu(*tmp);
 236
 237                         pr_debug(" -> newintsize=%d, newaddrsize=%d\n",
 238                             newintsize, newaddrsize);
 239
 240                         /* Check for malformed properties */
 241                         if (imaplen < (newaddrsize + newintsize))
 242                                 goto fail;
 243
 244                         imap += newaddrsize + newintsize;
 245                         imaplen -= newaddrsize + newintsize;
 246
 247                         pr_debug(" -> imaplen=%d\n", imaplen);
 248                 }
 249                 if (!match)
 250                         goto fail;
 251
 252                 of_node_put(old);
 253                 old = of_node_get(newpar);
 254                 addrsize = newaddrsize;
 255                 intsize = newintsize;
 256                 intspec = imap - intsize;
 257                 addr = intspec - addrsize;
 258
 259         skiplevel:
 260                 /* Iterate again with new parent */
 261                 pr_debug(" -> new parent: %s\n", newpar ? newpar->full_name : "<>");
 262                 of_node_put(ipar);
 263                 ipar = newpar;
 264                 newpar = NULL;
 265         }
 266  fail:
 267         of_node_put(ipar);
 268         of_node_put(old);
 269         of_node_put(newpar);
 270
 271         return -EINVAL;
 272 }
 273 EXPORT_SYMBOL_GPL(of_irq_map_raw);
 274
 275 /**
 276  * of_irq_map_one - Resolve an interrupt for a device
 277  * @device: the device whose interrupt is to be resolved
 278  * @index: index of the interrupt to resolve
 279  * @out_irq: structure of_irq filled by this function
 280  *
 281  * This function resolves an interrupt, walking the tree, for a given
 282  * device-tree node. It's the high level pendant to of_irq_map_raw().
 283  */
 284 int of_irq_map_one(struct device_node *device, int index, struct of_irq *out_irq)
 285 {
 286         struct device_node *p;
 287         const __be32 *intspec, *tmp, *addr;
 288         u32 intsize, intlen;
 289         int res = -EINVAL;
 290
 291         pr_debug("of_irq_map_one: dev=%s, index=%d\n", device->full_name, index);
 292
 293         /* OldWorld mac stuff is "special", handle out of line */
 294         if (of_irq_workarounds & OF_IMAP_OLDWORLD_MAC)
 295                 return of_irq_map_oldworld(device, index, out_irq);
 296
 297         /* Get the interrupts property */
 298         intspec = of_get_property(device, "interrupts", &intlen);
 299         if (intspec == NULL)
 300                 return -EINVAL;
 301         intlen /= sizeof(*intspec);
 302
 303         pr_debug(" intspec=%d intlen=%d\n", be32_to_cpup(intspec), intlen);
 304
 305         /* Get the reg property (if any) */
 306         addr = of_get_property(device, "reg", NULL);
 307
 308         /* Look for the interrupt parent. */
 309         p = of_irq_find_parent(device);
 310         if (p == NULL)
 311                 return -EINVAL;
 312
 313         /* Get size of interrupt specifier */
 314         tmp = of_get_property(p, "#interrupt-cells", NULL);
 315         if (tmp == NULL)
 316                 goto out;
 317         intsize = be32_to_cpu(*tmp);
 318
 319         pr_debug(" intsize=%d intlen=%d\n", intsize, intlen);
 320
 321         /* Check index */
 322         if ((index + 1) * intsize > intlen)
 323                 goto out;
 324
 325         /* Get new specifier and map it */
 326         res = of_irq_map_raw(p, intspec + index * intsize, intsize,
 327                              addr, out_irq);
 328  out:
 329         of_node_put(p);
 330         return res;
 331 }
 332 EXPORT_SYMBOL_GPL(of_irq_map_one);
 333
 334 /**
 335  * of_irq_to_resource - Decode a node's IRQ and return it as a resource
 336  * @dev: pointer to device tree node
 337  * @index: zero-based index of the irq
 338  * @r: pointer to resource structure to return result into.
 339  */
 340 int of_irq_to_resource(struct device_node *dev, int index, struct resource *r)
 341 {
 342         int irq = irq_of_parse_and_map(dev, index);
 343
 344         /* Only dereference the resource if both the
 345          * resource and the irq are valid. */
 346         if (r && irq != NO_IRQ) {
 347                 r->start = r->end = irq;
 348                 r->flags = IORESOURCE_IRQ;
 349                 r->name = dev->full_name;
 350         }
 351
 352         return irq;
 353 }
 354 EXPORT_SYMBOL_GPL(of_irq_to_resource);
 355
 356 /**
 357  * of_irq_count - Count the number of IRQs a node uses
 358  * @dev: pointer to device tree node
 359  */
 360 int of_irq_count(struct device_node *dev)
 361 {
 362         int nr = 0;
 363
 364         while (of_irq_to_resource(dev, nr, NULL) != NO_IRQ)
 365                 nr++;
 366
 367         return nr;
 368 }
 369
 370 /**
 371  * of_irq_to_resource_table - Fill in resource table with node's IRQ info
 372  * @dev: pointer to device tree node
 373  * @res: array of resources to fill in
 374  * @nr_irqs: the number of IRQs (and upper bound for num of @res elements)
 375  *
 376  * Returns the size of the filled in table (up to @nr_irqs).
 377  */
 378 int of_irq_to_resource_table(struct device_node *dev, struct resource *res,
 379                 int nr_irqs)
 380 {
 381         int i;
 382
 383         for (i = 0; i < nr_irqs; i++, res++)
 384                 if (of_irq_to_resource(dev, i, res) == NO_IRQ)
 385                         break;
 386
 387         return i;
 388 }