Root/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/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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