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Linux/drivers/of/platform.c

  1 /*
  2  *    Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corp.
  3  *                       <benh@kernel.crashing.org>
  4  *    and                Arnd Bergmann, IBM Corp.
  5  *    Merged from powerpc/kernel/of_platform.c and
  6  *    sparc{,64}/kernel/of_device.c by Stephen Rothwell
  7  *
  8  *  This program is free software; you can redistribute it and/or
  9  *  modify it under the terms of the GNU General Public License
 10  *  as published by the Free Software Foundation; either version
 11  *  2 of the License, or (at your option) any later version.
 12  *
 13  */
 14 #include <linux/errno.h>
 15 #include <linux/module.h>
 16 #include <linux/amba/bus.h>
 17 #include <linux/device.h>
 18 #include <linux/dma-mapping.h>
 19 #include <linux/slab.h>
 20 #include <linux/of_address.h>
 21 #include <linux/of_device.h>
 22 #include <linux/of_irq.h>
 23 #include <linux/of_platform.h>
 24 #include <linux/platform_device.h>
 25 
 26 const struct of_device_id of_default_bus_match_table[] = {
 27         { .compatible = "simple-bus", },
 28 #ifdef CONFIG_ARM_AMBA
 29         { .compatible = "arm,amba-bus", },
 30 #endif /* CONFIG_ARM_AMBA */
 31         {} /* Empty terminated list */
 32 };
 33 
 34 static int of_dev_node_match(struct device *dev, void *data)
 35 {
 36         return dev->of_node == data;
 37 }
 38 
 39 /**
 40  * of_find_device_by_node - Find the platform_device associated with a node
 41  * @np: Pointer to device tree node
 42  *
 43  * Returns platform_device pointer, or NULL if not found
 44  */
 45 struct platform_device *of_find_device_by_node(struct device_node *np)
 46 {
 47         struct device *dev;
 48 
 49         dev = bus_find_device(&platform_bus_type, NULL, np, of_dev_node_match);
 50         return dev ? to_platform_device(dev) : NULL;
 51 }
 52 EXPORT_SYMBOL(of_find_device_by_node);
 53 
 54 #ifdef CONFIG_OF_ADDRESS
 55 /*
 56  * The following routines scan a subtree and registers a device for
 57  * each applicable node.
 58  *
 59  * Note: sparc doesn't use these routines because it has a different
 60  * mechanism for creating devices from device tree nodes.
 61  */
 62 
 63 /**
 64  * of_device_make_bus_id - Use the device node data to assign a unique name
 65  * @dev: pointer to device structure that is linked to a device tree node
 66  *
 67  * This routine will first try using the translated bus address to
 68  * derive a unique name. If it cannot, then it will prepend names from
 69  * parent nodes until a unique name can be derived.
 70  */
 71 void of_device_make_bus_id(struct device *dev)
 72 {
 73         struct device_node *node = dev->of_node;
 74         const __be32 *reg;
 75         u64 addr;
 76 
 77         /* Construct the name, using parent nodes if necessary to ensure uniqueness */
 78         while (node->parent) {
 79                 /*
 80                  * If the address can be translated, then that is as much
 81                  * uniqueness as we need. Make it the first component and return
 82                  */
 83                 reg = of_get_property(node, "reg", NULL);
 84                 if (reg && (addr = of_translate_address(node, reg)) != OF_BAD_ADDR) {
 85                         dev_set_name(dev, dev_name(dev) ? "%llx.%s:%s" : "%llx.%s",
 86                                      (unsigned long long)addr, node->name,
 87                                      dev_name(dev));
 88                         return;
 89                 }
 90 
 91                 /* format arguments only used if dev_name() resolves to NULL */
 92                 dev_set_name(dev, dev_name(dev) ? "%s:%s" : "%s",
 93                              strrchr(node->full_name, '/') + 1, dev_name(dev));
 94                 node = node->parent;
 95         }
 96 }
 97 
 98 /**
 99  * of_device_alloc - Allocate and initialize an of_device
100  * @np: device node to assign to device
101  * @bus_id: Name to assign to the device.  May be null to use default name.
102  * @parent: Parent device.
103  */
104 struct platform_device *of_device_alloc(struct device_node *np,
105                                   const char *bus_id,
106                                   struct device *parent)
107 {
108         struct platform_device *dev;
109         int rc, i, num_reg = 0, num_irq;
110         struct resource *res, temp_res;
111 
112         dev = platform_device_alloc("", -1);
113         if (!dev)
114                 return NULL;
115 
116         /* count the io and irq resources */
117         while (of_address_to_resource(np, num_reg, &temp_res) == 0)
118                 num_reg++;
119         num_irq = of_irq_count(np);
120 
121         /* Populate the resource table */
122         if (num_irq || num_reg) {
123                 res = kzalloc(sizeof(*res) * (num_irq + num_reg), GFP_KERNEL);
124                 if (!res) {
125                         platform_device_put(dev);
126                         return NULL;
127                 }
128 
129                 dev->num_resources = num_reg + num_irq;
130                 dev->resource = res;
131                 for (i = 0; i < num_reg; i++, res++) {
132                         rc = of_address_to_resource(np, i, res);
133                         WARN_ON(rc);
134                 }
135                 if (of_irq_to_resource_table(np, res, num_irq) != num_irq)
136                         pr_debug("not all legacy IRQ resources mapped for %s\n",
137                                  np->name);
138         }
139 
140         dev->dev.of_node = of_node_get(np);
141         dev->dev.parent = parent ? : &platform_bus;
142 
143         if (bus_id)
144                 dev_set_name(&dev->dev, "%s", bus_id);
145         else
146                 of_device_make_bus_id(&dev->dev);
147 
148         return dev;
149 }
150 EXPORT_SYMBOL(of_device_alloc);
151 
152 static void of_dma_deconfigure(struct device *dev)
153 {
154         arch_teardown_dma_ops(dev);
155 }
156 
157 /**
158  * of_platform_device_create_pdata - Alloc, initialize and register an of_device
159  * @np: pointer to node to create device for
160  * @bus_id: name to assign device
161  * @platform_data: pointer to populate platform_data pointer with
162  * @parent: Linux device model parent device.
163  *
164  * Returns pointer to created platform device, or NULL if a device was not
165  * registered.  Unavailable devices will not get registered.
166  */
167 static struct platform_device *of_platform_device_create_pdata(
168                                         struct device_node *np,
169                                         const char *bus_id,
170                                         void *platform_data,
171                                         struct device *parent)
172 {
173         struct platform_device *dev;
174 
175         if (!of_device_is_available(np) ||
176             of_node_test_and_set_flag(np, OF_POPULATED))
177                 return NULL;
178 
179         dev = of_device_alloc(np, bus_id, parent);
180         if (!dev)
181                 goto err_clear_flag;
182 
183         dev->dev.bus = &platform_bus_type;
184         dev->dev.platform_data = platform_data;
185         of_dma_configure(&dev->dev, dev->dev.of_node);
186 
187         if (of_device_add(dev) != 0) {
188                 of_dma_deconfigure(&dev->dev);
189                 platform_device_put(dev);
190                 goto err_clear_flag;
191         }
192 
193         return dev;
194 
195 err_clear_flag:
196         of_node_clear_flag(np, OF_POPULATED);
197         return NULL;
198 }
199 
200 /**
201  * of_platform_device_create - Alloc, initialize and register an of_device
202  * @np: pointer to node to create device for
203  * @bus_id: name to assign device
204  * @parent: Linux device model parent device.
205  *
206  * Returns pointer to created platform device, or NULL if a device was not
207  * registered.  Unavailable devices will not get registered.
208  */
209 struct platform_device *of_platform_device_create(struct device_node *np,
210                                             const char *bus_id,
211                                             struct device *parent)
212 {
213         return of_platform_device_create_pdata(np, bus_id, NULL, parent);
214 }
215 EXPORT_SYMBOL(of_platform_device_create);
216 
217 #ifdef CONFIG_ARM_AMBA
218 static struct amba_device *of_amba_device_create(struct device_node *node,
219                                                  const char *bus_id,
220                                                  void *platform_data,
221                                                  struct device *parent)
222 {
223         struct amba_device *dev;
224         const void *prop;
225         int i, ret;
226 
227         pr_debug("Creating amba device %s\n", node->full_name);
228 
229         if (!of_device_is_available(node) ||
230             of_node_test_and_set_flag(node, OF_POPULATED))
231                 return NULL;
232 
233         dev = amba_device_alloc(NULL, 0, 0);
234         if (!dev) {
235                 pr_err("%s(): amba_device_alloc() failed for %s\n",
236                        __func__, node->full_name);
237                 goto err_clear_flag;
238         }
239 
240         /* setup generic device info */
241         dev->dev.of_node = of_node_get(node);
242         dev->dev.parent = parent ? : &platform_bus;
243         dev->dev.platform_data = platform_data;
244         if (bus_id)
245                 dev_set_name(&dev->dev, "%s", bus_id);
246         else
247                 of_device_make_bus_id(&dev->dev);
248         of_dma_configure(&dev->dev, dev->dev.of_node);
249 
250         /* Allow the HW Peripheral ID to be overridden */
251         prop = of_get_property(node, "arm,primecell-periphid", NULL);
252         if (prop)
253                 dev->periphid = of_read_ulong(prop, 1);
254 
255         /* Decode the IRQs and address ranges */
256         for (i = 0; i < AMBA_NR_IRQS; i++)
257                 dev->irq[i] = irq_of_parse_and_map(node, i);
258 
259         ret = of_address_to_resource(node, 0, &dev->res);
260         if (ret) {
261                 pr_err("%s(): of_address_to_resource() failed (%d) for %s\n",
262                        __func__, ret, node->full_name);
263                 goto err_free;
264         }
265 
266         ret = amba_device_add(dev, &iomem_resource);
267         if (ret) {
268                 pr_err("%s(): amba_device_add() failed (%d) for %s\n",
269                        __func__, ret, node->full_name);
270                 goto err_free;
271         }
272 
273         return dev;
274 
275 err_free:
276         amba_device_put(dev);
277 err_clear_flag:
278         of_node_clear_flag(node, OF_POPULATED);
279         return NULL;
280 }
281 #else /* CONFIG_ARM_AMBA */
282 static struct amba_device *of_amba_device_create(struct device_node *node,
283                                                  const char *bus_id,
284                                                  void *platform_data,
285                                                  struct device *parent)
286 {
287         return NULL;
288 }
289 #endif /* CONFIG_ARM_AMBA */
290 
291 /**
292  * of_devname_lookup() - Given a device node, lookup the preferred Linux name
293  */
294 static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *lookup,
295                                  struct device_node *np)
296 {
297         struct resource res;
298 
299         if (!lookup)
300                 return NULL;
301 
302         for(; lookup->compatible != NULL; lookup++) {
303                 if (!of_device_is_compatible(np, lookup->compatible))
304                         continue;
305                 if (!of_address_to_resource(np, 0, &res))
306                         if (res.start != lookup->phys_addr)
307                                 continue;
308                 pr_debug("%s: devname=%s\n", np->full_name, lookup->name);
309                 return lookup;
310         }
311 
312         return NULL;
313 }
314 
315 /**
316  * of_platform_bus_create() - Create a device for a node and its children.
317  * @bus: device node of the bus to instantiate
318  * @matches: match table for bus nodes
319  * @lookup: auxdata table for matching id and platform_data with device nodes
320  * @parent: parent for new device, or NULL for top level.
321  * @strict: require compatible property
322  *
323  * Creates a platform_device for the provided device_node, and optionally
324  * recursively create devices for all the child nodes.
325  */
326 static int of_platform_bus_create(struct device_node *bus,
327                                   const struct of_device_id *matches,
328                                   const struct of_dev_auxdata *lookup,
329                                   struct device *parent, bool strict)
330 {
331         const struct of_dev_auxdata *auxdata;
332         struct device_node *child;
333         struct platform_device *dev;
334         const char *bus_id = NULL;
335         void *platform_data = NULL;
336         int rc = 0;
337 
338         /* Make sure it has a compatible property */
339         if (strict && (!of_get_property(bus, "compatible", NULL))) {
340                 pr_debug("%s() - skipping %s, no compatible prop\n",
341                          __func__, bus->full_name);
342                 return 0;
343         }
344 
345         auxdata = of_dev_lookup(lookup, bus);
346         if (auxdata) {
347                 bus_id = auxdata->name;
348                 platform_data = auxdata->platform_data;
349         }
350 
351         if (of_device_is_compatible(bus, "arm,primecell")) {
352                 /*
353                  * Don't return an error here to keep compatibility with older
354                  * device tree files.
355                  */
356                 of_amba_device_create(bus, bus_id, platform_data, parent);
357                 return 0;
358         }
359 
360         dev = of_platform_device_create_pdata(bus, bus_id, platform_data, parent);
361         if (!dev || !of_match_node(matches, bus))
362                 return 0;
363 
364         for_each_child_of_node(bus, child) {
365                 pr_debug("   create child: %s\n", child->full_name);
366                 rc = of_platform_bus_create(child, matches, lookup, &dev->dev, strict);
367                 if (rc) {
368                         of_node_put(child);
369                         break;
370                 }
371         }
372         of_node_set_flag(bus, OF_POPULATED_BUS);
373         return rc;
374 }
375 
376 /**
377  * of_platform_bus_probe() - Probe the device-tree for platform buses
378  * @root: parent of the first level to probe or NULL for the root of the tree
379  * @matches: match table for bus nodes
380  * @parent: parent to hook devices from, NULL for toplevel
381  *
382  * Note that children of the provided root are not instantiated as devices
383  * unless the specified root itself matches the bus list and is not NULL.
384  */
385 int of_platform_bus_probe(struct device_node *root,
386                           const struct of_device_id *matches,
387                           struct device *parent)
388 {
389         struct device_node *child;
390         int rc = 0;
391 
392         root = root ? of_node_get(root) : of_find_node_by_path("/");
393         if (!root)
394                 return -EINVAL;
395 
396         pr_debug("of_platform_bus_probe()\n");
397         pr_debug(" starting at: %s\n", root->full_name);
398 
399         /* Do a self check of bus type, if there's a match, create children */
400         if (of_match_node(matches, root)) {
401                 rc = of_platform_bus_create(root, matches, NULL, parent, false);
402         } else for_each_child_of_node(root, child) {
403                 if (!of_match_node(matches, child))
404                         continue;
405                 rc = of_platform_bus_create(child, matches, NULL, parent, false);
406                 if (rc)
407                         break;
408         }
409 
410         of_node_put(root);
411         return rc;
412 }
413 EXPORT_SYMBOL(of_platform_bus_probe);
414 
415 /**
416  * of_platform_populate() - Populate platform_devices from device tree data
417  * @root: parent of the first level to probe or NULL for the root of the tree
418  * @matches: match table, NULL to use the default
419  * @lookup: auxdata table for matching id and platform_data with device nodes
420  * @parent: parent to hook devices from, NULL for toplevel
421  *
422  * Similar to of_platform_bus_probe(), this function walks the device tree
423  * and creates devices from nodes.  It differs in that it follows the modern
424  * convention of requiring all device nodes to have a 'compatible' property,
425  * and it is suitable for creating devices which are children of the root
426  * node (of_platform_bus_probe will only create children of the root which
427  * are selected by the @matches argument).
428  *
429  * New board support should be using this function instead of
430  * of_platform_bus_probe().
431  *
432  * Returns 0 on success, < 0 on failure.
433  */
434 int of_platform_populate(struct device_node *root,
435                         const struct of_device_id *matches,
436                         const struct of_dev_auxdata *lookup,
437                         struct device *parent)
438 {
439         struct device_node *child;
440         int rc = 0;
441 
442         root = root ? of_node_get(root) : of_find_node_by_path("/");
443         if (!root)
444                 return -EINVAL;
445 
446         for_each_child_of_node(root, child) {
447                 rc = of_platform_bus_create(child, matches, lookup, parent, true);
448                 if (rc)
449                         break;
450         }
451         of_node_set_flag(root, OF_POPULATED_BUS);
452 
453         of_node_put(root);
454         return rc;
455 }
456 EXPORT_SYMBOL_GPL(of_platform_populate);
457 
458 static int of_platform_device_destroy(struct device *dev, void *data)
459 {
460         /* Do not touch devices not populated from the device tree */
461         if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED))
462                 return 0;
463 
464         /* Recurse for any nodes that were treated as busses */
465         if (of_node_check_flag(dev->of_node, OF_POPULATED_BUS))
466                 device_for_each_child(dev, NULL, of_platform_device_destroy);
467 
468         if (dev->bus == &platform_bus_type)
469                 platform_device_unregister(to_platform_device(dev));
470 #ifdef CONFIG_ARM_AMBA
471         else if (dev->bus == &amba_bustype)
472                 amba_device_unregister(to_amba_device(dev));
473 #endif
474 
475         of_dma_deconfigure(dev);
476         of_node_clear_flag(dev->of_node, OF_POPULATED);
477         of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
478         return 0;
479 }
480 
481 /**
482  * of_platform_depopulate() - Remove devices populated from device tree
483  * @parent: device which children will be removed
484  *
485  * Complementary to of_platform_populate(), this function removes children
486  * of the given device (and, recurrently, their children) that have been
487  * created from their respective device tree nodes (and only those,
488  * leaving others - eg. manually created - unharmed).
489  *
490  * Returns 0 when all children devices have been removed or
491  * -EBUSY when some children remained.
492  */
493 void of_platform_depopulate(struct device *parent)
494 {
495         if (parent->of_node && of_node_check_flag(parent->of_node, OF_POPULATED_BUS)) {
496                 device_for_each_child(parent, NULL, of_platform_device_destroy);
497                 of_node_clear_flag(parent->of_node, OF_POPULATED_BUS);
498         }
499 }
500 EXPORT_SYMBOL_GPL(of_platform_depopulate);
501 
502 #ifdef CONFIG_OF_DYNAMIC
503 static int of_platform_notify(struct notifier_block *nb,
504                                 unsigned long action, void *arg)
505 {
506         struct of_reconfig_data *rd = arg;
507         struct platform_device *pdev_parent, *pdev;
508         bool children_left;
509 
510         switch (of_reconfig_get_state_change(action, rd)) {
511         case OF_RECONFIG_CHANGE_ADD:
512                 /* verify that the parent is a bus */
513                 if (!of_node_check_flag(rd->dn->parent, OF_POPULATED_BUS))
514                         return NOTIFY_OK;       /* not for us */
515 
516                 /* already populated? (driver using of_populate manually) */
517                 if (of_node_check_flag(rd->dn, OF_POPULATED))
518                         return NOTIFY_OK;
519 
520                 /* pdev_parent may be NULL when no bus platform device */
521                 pdev_parent = of_find_device_by_node(rd->dn->parent);
522                 pdev = of_platform_device_create(rd->dn, NULL,
523                                 pdev_parent ? &pdev_parent->dev : NULL);
524                 of_dev_put(pdev_parent);
525 
526                 if (pdev == NULL) {
527                         pr_err("%s: failed to create for '%s'\n",
528                                         __func__, rd->dn->full_name);
529                         /* of_platform_device_create tosses the error code */
530                         return notifier_from_errno(-EINVAL);
531                 }
532                 break;
533 
534         case OF_RECONFIG_CHANGE_REMOVE:
535 
536                 /* already depopulated? */
537                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
538                         return NOTIFY_OK;
539 
540                 /* find our device by node */
541                 pdev = of_find_device_by_node(rd->dn);
542                 if (pdev == NULL)
543                         return NOTIFY_OK;       /* no? not meant for us */
544 
545                 /* unregister takes one ref away */
546                 of_platform_device_destroy(&pdev->dev, &children_left);
547 
548                 /* and put the reference of the find */
549                 of_dev_put(pdev);
550                 break;
551         }
552 
553         return NOTIFY_OK;
554 }
555 
556 static struct notifier_block platform_of_notifier = {
557         .notifier_call = of_platform_notify,
558 };
559 
560 void of_platform_register_reconfig_notifier(void)
561 {
562         WARN_ON(of_reconfig_notifier_register(&platform_of_notifier));
563 }
564 #endif /* CONFIG_OF_DYNAMIC */
565 
566 #endif /* CONFIG_OF_ADDRESS */
567 

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