linux/drivers/of/irq.c
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   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/list.h>
  23#include <linux/module.h>
  24#include <linux/of.h>
  25#include <linux/of_irq.h>
  26#include <linux/string.h>
  27#include <linux/slab.h>
  28
  29/**
  30 * irq_of_parse_and_map - Parse and map an interrupt into linux virq space
  31 * @device: Device node of the device whose interrupt is to be mapped
  32 * @index: Index of the interrupt to map
  33 *
  34 * This function is a wrapper that chains of_irq_map_one() and
  35 * irq_create_of_mapping() to make things easier to callers
  36 */
  37unsigned int irq_of_parse_and_map(struct device_node *dev, int index)
  38{
  39        struct of_irq oirq;
  40
  41        if (of_irq_map_one(dev, index, &oirq))
  42                return 0;
  43
  44        return irq_create_of_mapping(oirq.controller, oirq.specifier,
  45                                     oirq.size);
  46}
  47EXPORT_SYMBOL_GPL(irq_of_parse_and_map);
  48
  49/**
  50 * of_irq_find_parent - Given a device node, find its interrupt parent node
  51 * @child: pointer to device node
  52 *
  53 * Returns a pointer to the interrupt parent node, or NULL if the interrupt
  54 * parent could not be determined.
  55 */
  56struct device_node *of_irq_find_parent(struct device_node *child)
  57{
  58        struct device_node *p;
  59        const __be32 *parp;
  60
  61        if (!of_node_get(child))
  62                return NULL;
  63
  64        do {
  65                parp = of_get_property(child, "interrupt-parent", NULL);
  66                if (parp == NULL)
  67                        p = of_get_parent(child);
  68                else {
  69                        if (of_irq_workarounds & OF_IMAP_NO_PHANDLE)
  70                                p = of_node_get(of_irq_dflt_pic);
  71                        else
  72                                p = of_find_node_by_phandle(be32_to_cpup(parp));
  73                }
  74                of_node_put(child);
  75                child = p;
  76        } while (p && of_get_property(p, "#interrupt-cells", NULL) == NULL);
  77
  78        return p;
  79}
  80
  81/**
  82 * of_irq_map_raw - Low level interrupt tree parsing
  83 * @parent:     the device interrupt parent
  84 * @intspec:    interrupt specifier ("interrupts" property of the device)
  85 * @ointsize:   size of the passed in interrupt specifier
  86 * @addr:       address specifier (start of "reg" property of the device)
  87 * @out_irq:    structure of_irq filled by this function
  88 *
  89 * Returns 0 on success and a negative number on error
  90 *
  91 * This function is a low-level interrupt tree walking function. It
  92 * can be used to do a partial walk with synthetized reg and interrupts
  93 * properties, for example when resolving PCI interrupts when no device
  94 * node exist for the parent.
  95 */
  96int of_irq_map_raw(struct device_node *parent, const __be32 *intspec,
  97                   u32 ointsize, const __be32 *addr, struct of_irq *out_irq)
  98{
  99        struct device_node *ipar, *tnode, *old = NULL, *newpar = NULL;
 100        const __be32 *tmp, *imap, *imask;
 101        u32 intsize = 1, addrsize, newintsize = 0, newaddrsize = 0;
 102        int imaplen, match, i;
 103
 104        pr_debug("of_irq_map_raw: par=%s,intspec=[0x%08x 0x%08x...],ointsize=%d\n",
 105                 parent->full_name, be32_to_cpup(intspec),
 106                 be32_to_cpup(intspec + 1), ointsize);
 107
 108        ipar = of_node_get(parent);
 109
 110        /* First get the #interrupt-cells property of the current cursor
 111         * that tells us how to interpret the passed-in intspec. If there
 112         * is none, we are nice and just walk up the tree
 113         */
 114        do {
 115                tmp = of_get_property(ipar, "#interrupt-cells", NULL);
 116                if (tmp != NULL) {
 117                        intsize = be32_to_cpu(*tmp);
 118                        break;
 119                }
 120                tnode = ipar;
 121                ipar = of_irq_find_parent(ipar);
 122                of_node_put(tnode);
 123        } while (ipar);
 124        if (ipar == NULL) {
 125                pr_debug(" -> no parent found !\n");
 126                goto fail;
 127        }
 128
 129        pr_debug("of_irq_map_raw: ipar=%s, size=%d\n", ipar->full_name, intsize);
 130
 131        if (ointsize != intsize)
 132                return -EINVAL;
 133
 134        /* Look for this #address-cells. We have to implement the old linux
 135         * trick of looking for the parent here as some device-trees rely on it
 136         */
 137        old = of_node_get(ipar);
 138        do {
 139                tmp = of_get_property(old, "#address-cells", NULL);
 140                tnode = of_get_parent(old);
 141                of_node_put(old);
 142                old = tnode;
 143        } while (old && tmp == NULL);
 144        of_node_put(old);
 145        old = NULL;
 146        addrsize = (tmp == NULL) ? 2 : be32_to_cpu(*tmp);
 147
 148        pr_debug(" -> addrsize=%d\n", addrsize);
 149
 150        /* Now start the actual "proper" walk of the interrupt tree */
 151        while (ipar != NULL) {
 152                /* Now check if cursor is an interrupt-controller and if it is
 153                 * then we are done
 154                 */
 155                if (of_get_property(ipar, "interrupt-controller", NULL) !=
 156                                NULL) {
 157                        pr_debug(" -> got it !\n");
 158                        for (i = 0; i < intsize; i++)
 159                                out_irq->specifier[i] =
 160                                                of_read_number(intspec +i, 1);
 161                        out_irq->size = intsize;
 162                        out_irq->controller = ipar;
 163                        of_node_put(old);
 164                        return 0;
 165                }
 166
 167                /* Now look for an interrupt-map */
 168                imap = of_get_property(ipar, "interrupt-map", &imaplen);
 169                /* No interrupt map, check for an interrupt parent */
 170                if (imap == NULL) {
 171                        pr_debug(" -> no map, getting parent\n");
 172                        newpar = of_irq_find_parent(ipar);
 173                        goto skiplevel;
 174                }
 175                imaplen /= sizeof(u32);
 176
 177                /* Look for a mask */
 178                imask = of_get_property(ipar, "interrupt-map-mask", NULL);
 179
 180                /* If we were passed no "reg" property and we attempt to parse
 181                 * an interrupt-map, then #address-cells must be 0.
 182                 * Fail if it's not.
 183                 */
 184                if (addr == NULL && addrsize != 0) {
 185                        pr_debug(" -> no reg passed in when needed !\n");
 186                        goto fail;
 187                }
 188
 189                /* Parse interrupt-map */
 190                match = 0;
 191                while (imaplen > (addrsize + intsize + 1) && !match) {
 192                        /* Compare specifiers */
 193                        match = 1;
 194                        for (i = 0; i < addrsize && match; ++i) {
 195                                u32 mask = imask ? imask[i] : 0xffffffffu;
 196                                match = ((addr[i] ^ imap[i]) & mask) == 0;
 197                        }
 198                        for (; i < (addrsize + intsize) && match; ++i) {
 199                                u32 mask = imask ? imask[i] : 0xffffffffu;
 200                                match =
 201                                   ((intspec[i-addrsize] ^ imap[i]) & mask) == 0;
 202                        }
 203                        imap += addrsize + intsize;
 204                        imaplen -= addrsize + intsize;
 205
 206                        pr_debug(" -> match=%d (imaplen=%d)\n", match, imaplen);
 207
 208                        /* Get the interrupt parent */
 209                        if (of_irq_workarounds & OF_IMAP_NO_PHANDLE)
 210                                newpar = of_node_get(of_irq_dflt_pic);
 211                        else
 212                                newpar = of_find_node_by_phandle(be32_to_cpup(imap));
 213                        imap++;
 214                        --imaplen;
 215
 216                        /* Check if not found */
 217                        if (newpar == NULL) {
 218                                pr_debug(" -> imap parent not found !\n");
 219                                goto fail;
 220                        }
 221
 222                        /* Get #interrupt-cells and #address-cells of new
 223                         * parent
 224                         */
 225                        tmp = of_get_property(newpar, "#interrupt-cells", NULL);
 226                        if (tmp == NULL) {
 227                                pr_debug(" -> parent lacks #interrupt-cells!\n");
 228                                goto fail;
 229                        }
 230                        newintsize = be32_to_cpu(*tmp);
 231                        tmp = of_get_property(newpar, "#address-cells", NULL);
 232                        newaddrsize = (tmp == NULL) ? 0 : be32_to_cpu(*tmp);
 233
 234                        pr_debug(" -> newintsize=%d, newaddrsize=%d\n",
 235                            newintsize, newaddrsize);
 236
 237                        /* Check for malformed properties */
 238                        if (imaplen < (newaddrsize + newintsize))
 239                                goto fail;
 240
 241                        imap += newaddrsize + newintsize;
 242                        imaplen -= newaddrsize + newintsize;
 243
 244                        pr_debug(" -> imaplen=%d\n", imaplen);
 245                }
 246                if (!match)
 247                        goto fail;
 248
 249                of_node_put(old);
 250                old = of_node_get(newpar);
 251                addrsize = newaddrsize;
 252                intsize = newintsize;
 253                intspec = imap - intsize;
 254                addr = intspec - addrsize;
 255
 256        skiplevel:
 257                /* Iterate again with new parent */
 258                pr_debug(" -> new parent: %s\n", of_node_full_name(newpar));
 259                of_node_put(ipar);
 260                ipar = newpar;
 261                newpar = NULL;
 262        }
 263 fail:
 264        of_node_put(ipar);
 265        of_node_put(old);
 266        of_node_put(newpar);
 267
 268        return -EINVAL;
 269}
 270EXPORT_SYMBOL_GPL(of_irq_map_raw);
 271
 272/**
 273 * of_irq_map_one - Resolve an interrupt for a device
 274 * @device: the device whose interrupt is to be resolved
 275 * @index: index of the interrupt to resolve
 276 * @out_irq: structure of_irq filled by this function
 277 *
 278 * This function resolves an interrupt, walking the tree, for a given
 279 * device-tree node. It's the high level pendant to of_irq_map_raw().
 280 */
 281int of_irq_map_one(struct device_node *device, int index, struct of_irq *out_irq)
 282{
 283        struct device_node *p;
 284        const __be32 *intspec, *tmp, *addr;
 285        u32 intsize, intlen;
 286        int res = -EINVAL;
 287
 288        pr_debug("of_irq_map_one: dev=%s, index=%d\n", device->full_name, index);
 289
 290        /* OldWorld mac stuff is "special", handle out of line */
 291        if (of_irq_workarounds & OF_IMAP_OLDWORLD_MAC)
 292                return of_irq_map_oldworld(device, index, out_irq);
 293
 294        /* Get the interrupts property */
 295        intspec = of_get_property(device, "interrupts", &intlen);
 296        if (intspec == NULL)
 297                return -EINVAL;
 298        intlen /= sizeof(*intspec);
 299
 300        pr_debug(" intspec=%d intlen=%d\n", be32_to_cpup(intspec), intlen);
 301
 302        /* Get the reg property (if any) */
 303        addr = of_get_property(device, "reg", NULL);
 304
 305        /* Look for the interrupt parent. */
 306        p = of_irq_find_parent(device);
 307        if (p == NULL)
 308                return -EINVAL;
 309
 310        /* Get size of interrupt specifier */
 311        tmp = of_get_property(p, "#interrupt-cells", NULL);
 312        if (tmp == NULL)
 313                goto out;
 314        intsize = be32_to_cpu(*tmp);
 315
 316        pr_debug(" intsize=%d intlen=%d\n", intsize, intlen);
 317
 318        /* Check index */
 319        if ((index + 1) * intsize > intlen)
 320                goto out;
 321
 322        /* Get new specifier and map it */
 323        res = of_irq_map_raw(p, intspec + index * intsize, intsize,
 324                             addr, out_irq);
 325 out:
 326        of_node_put(p);
 327        return res;
 328}
 329EXPORT_SYMBOL_GPL(of_irq_map_one);
 330
 331/**
 332 * of_irq_to_resource - Decode a node's IRQ and return it as a resource
 333 * @dev: pointer to device tree node
 334 * @index: zero-based index of the irq
 335 * @r: pointer to resource structure to return result into.
 336 */
 337int of_irq_to_resource(struct device_node *dev, int index, struct resource *r)
 338{
 339        int irq = irq_of_parse_and_map(dev, index);
 340
 341        /* Only dereference the resource if both the
 342         * resource and the irq are valid. */
 343        if (r && irq) {
 344                const char *name = NULL;
 345
 346                /*
 347                 * Get optional "interrupts-names" property to add a name
 348                 * to the resource.
 349                 */
 350                of_property_read_string_index(dev, "interrupt-names", index,
 351                                              &name);
 352
 353                r->start = r->end = irq;
 354                r->flags = IORESOURCE_IRQ;
 355                r->name = name ? name : dev->full_name;
 356        }
 357
 358        return irq;
 359}
 360EXPORT_SYMBOL_GPL(of_irq_to_resource);
 361
 362/**
 363 * of_irq_count - Count the number of IRQs a node uses
 364 * @dev: pointer to device tree node
 365 */
 366int of_irq_count(struct device_node *dev)
 367{
 368        int nr = 0;
 369
 370        while (of_irq_to_resource(dev, nr, NULL))
 371                nr++;
 372
 373        return nr;
 374}
 375
 376/**
 377 * of_irq_to_resource_table - Fill in resource table with node's IRQ info
 378 * @dev: pointer to device tree node
 379 * @res: array of resources to fill in
 380 * @nr_irqs: the number of IRQs (and upper bound for num of @res elements)
 381 *
 382 * Returns the size of the filled in table (up to @nr_irqs).
 383 */
 384int of_irq_to_resource_table(struct device_node *dev, struct resource *res,
 385                int nr_irqs)
 386{
 387        int i;
 388
 389        for (i = 0; i < nr_irqs; i++, res++)
 390                if (!of_irq_to_resource(dev, i, res))
 391                        break;
 392
 393        return i;
 394}
 395
 396struct intc_desc {
 397        struct list_head        list;
 398        struct device_node      *dev;
 399        struct device_node      *interrupt_parent;
 400};
 401
 402/**
 403 * of_irq_init - Scan and init matching interrupt controllers in DT
 404 * @matches: 0 terminated array of nodes to match and init function to call
 405 *
 406 * This function scans the device tree for matching interrupt controller nodes,
 407 * and calls their initialization functions in order with parents first.
 408 */
 409void __init of_irq_init(const struct of_device_id *matches)
 410{
 411        struct device_node *np, *parent = NULL;
 412        struct intc_desc *desc, *temp_desc;
 413        struct list_head intc_desc_list, intc_parent_list;
 414
 415        INIT_LIST_HEAD(&intc_desc_list);
 416        INIT_LIST_HEAD(&intc_parent_list);
 417
 418        for_each_matching_node(np, matches) {
 419                if (!of_find_property(np, "interrupt-controller", NULL))
 420                        continue;
 421                /*
 422                 * Here, we allocate and populate an intc_desc with the node
 423                 * pointer, interrupt-parent device_node etc.
 424                 */
 425                desc = kzalloc(sizeof(*desc), GFP_KERNEL);
 426                if (WARN_ON(!desc))
 427                        goto err;
 428
 429                desc->dev = np;
 430                desc->interrupt_parent = of_irq_find_parent(np);
 431                if (desc->interrupt_parent == np)
 432                        desc->interrupt_parent = NULL;
 433                list_add_tail(&desc->list, &intc_desc_list);
 434        }
 435
 436        /*
 437         * The root irq controller is the one without an interrupt-parent.
 438         * That one goes first, followed by the controllers that reference it,
 439         * followed by the ones that reference the 2nd level controllers, etc.
 440         */
 441        while (!list_empty(&intc_desc_list)) {
 442                /*
 443                 * Process all controllers with the current 'parent'.
 444                 * First pass will be looking for NULL as the parent.
 445                 * The assumption is that NULL parent means a root controller.
 446                 */
 447                list_for_each_entry_safe(desc, temp_desc, &intc_desc_list, list) {
 448                        const struct of_device_id *match;
 449                        int ret;
 450                        of_irq_init_cb_t irq_init_cb;
 451
 452                        if (desc->interrupt_parent != parent)
 453                                continue;
 454
 455                        list_del(&desc->list);
 456                        match = of_match_node(matches, desc->dev);
 457                        if (WARN(!match->data,
 458                            "of_irq_init: no init function for %s\n",
 459                            match->compatible)) {
 460                                kfree(desc);
 461                                continue;
 462                        }
 463
 464                        pr_debug("of_irq_init: init %s @ %p, parent %p\n",
 465                                 match->compatible,
 466                                 desc->dev, desc->interrupt_parent);
 467                        irq_init_cb = match->data;
 468                        ret = irq_init_cb(desc->dev, desc->interrupt_parent);
 469                        if (ret) {
 470                                kfree(desc);
 471                                continue;
 472                        }
 473
 474                        /*
 475                         * This one is now set up; add it to the parent list so
 476                         * its children can get processed in a subsequent pass.
 477                         */
 478                        list_add_tail(&desc->list, &intc_parent_list);
 479                }
 480
 481                /* Get the next pending parent that might have children */
 482                desc = list_first_entry(&intc_parent_list, typeof(*desc), list);
 483                if (list_empty(&intc_parent_list) || !desc) {
 484                        pr_err("of_irq_init: children remain, but no parents\n");
 485                        break;
 486                }
 487                list_del(&desc->list);
 488                parent = desc->dev;
 489                kfree(desc);
 490        }
 491
 492        list_for_each_entry_safe(desc, temp_desc, &intc_parent_list, list) {
 493                list_del(&desc->list);
 494                kfree(desc);
 495        }
 496err:
 497        list_for_each_entry_safe(desc, temp_desc, &intc_desc_list, list) {
 498                list_del(&desc->list);
 499                kfree(desc);
 500        }
 501}
 502
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