/arch/ppc64/kernel/pSeries_reconfig.c

  1/*
  2 * pSeries_reconfig.c - support for dynamic reconfiguration (including PCI
  3 * Hotplug and Dynamic Logical Partitioning on RPA platforms).
  4 *
  5 * Copyright (C) 2005 Nathan Lynch
  6 * Copyright (C) 2005 IBM Corporation
  7 *
  8 *
  9 *	This program is free software; you can redistribute it and/or
 10 *	modify it under the terms of the GNU General Public License version
 11 *	2 as published by the Free Software Foundation.
 12 */
 13
 14#include <linux/kernel.h>
 15#include <linux/kref.h>
 16#include <linux/notifier.h>
 17#include <linux/proc_fs.h>
 18
 19#include <asm/prom.h>
 20#include <asm/pSeries_reconfig.h>
 21#include <asm/uaccess.h>
 22
 23
 24
 25/*
 26 * Routines for "runtime" addition and removal of device tree nodes.
 27 */
 28#ifdef CONFIG_PROC_DEVICETREE
 29/*
 30 * Add a node to /proc/device-tree.
 31 */
 32static void add_node_proc_entries(struct device_node *np)
 33{
 34	struct proc_dir_entry *ent;
 35
 36	ent = proc_mkdir(strrchr(np->full_name, '/') + 1, np->parent->pde);
 37	if (ent)
 38		proc_device_tree_add_node(np, ent);
 39}
 40
 41static void remove_node_proc_entries(struct device_node *np)
 42{
 43	struct property *pp = np->properties;
 44	struct device_node *parent = np->parent;
 45
 46	while (pp) {
 47		remove_proc_entry(pp->name, np->pde);
 48		pp = pp->next;
 49	}
 50
 51	/* Assuming that symlinks have the same parent directory as
 52	 * np->pde.
 53	 */
 54	if (np->name_link)
 55		remove_proc_entry(np->name_link->name, parent->pde);
 56	if (np->addr_link)
 57		remove_proc_entry(np->addr_link->name, parent->pde);
 58	if (np->pde)
 59		remove_proc_entry(np->pde->name, parent->pde);
 60}
 61#else /* !CONFIG_PROC_DEVICETREE */
 62static void add_node_proc_entries(struct device_node *np)
 63{
 64	return;
 65}
 66
 67static void remove_node_proc_entries(struct device_node *np)
 68{
 69	return;
 70}
 71#endif /* CONFIG_PROC_DEVICETREE */
 72
 73/**
 74 *	derive_parent - basically like dirname(1)
 75 *	@path:  the full_name of a node to be added to the tree
 76 *
 77 *	Returns the node which should be the parent of the node
 78 *	described by path.  E.g., for path = "/foo/bar", returns
 79 *	the node with full_name = "/foo".
 80 */
 81static struct device_node *derive_parent(const char *path)
 82{
 83	struct device_node *parent = NULL;
 84	char *parent_path = "/";
 85	size_t parent_path_len = strrchr(path, '/') - path + 1;
 86
 87	/* reject if path is "/" */
 88	if (!strcmp(path, "/"))
 89		return ERR_PTR(-EINVAL);
 90
 91	if (strrchr(path, '/') != path) {
 92		parent_path = kmalloc(parent_path_len, GFP_KERNEL);
 93		if (!parent_path)
 94			return ERR_PTR(-ENOMEM);
 95		strlcpy(parent_path, path, parent_path_len);
 96	}
 97	parent = of_find_node_by_path(parent_path);
 98	if (!parent)
 99		return ERR_PTR(-EINVAL);
100	if (strcmp(parent_path, "/"))
101		kfree(parent_path);
102	return parent;
103}
104
105static struct notifier_block *pSeries_reconfig_chain;
106
107int pSeries_reconfig_notifier_register(struct notifier_block *nb)
108{
109	return notifier_chain_register(&pSeries_reconfig_chain, nb);
110}
111
112void pSeries_reconfig_notifier_unregister(struct notifier_block *nb)
113{
114	notifier_chain_unregister(&pSeries_reconfig_chain, nb);
115}
116
117static int pSeries_reconfig_add_node(const char *path, struct property *proplist)
118{
119	struct device_node *np;
120	int err = -ENOMEM;
121
122	np = kcalloc(1, sizeof(*np), GFP_KERNEL);
123	if (!np)
124		goto out_err;
125
126	np->full_name = kmalloc(strlen(path) + 1, GFP_KERNEL);
127	if (!np->full_name)
128		goto out_err;
129
130	strcpy(np->full_name, path);
131
132	np->properties = proplist;
133	OF_MARK_DYNAMIC(np);
134	kref_init(&np->kref);
135
136	np->parent = derive_parent(path);
137	if (IS_ERR(np->parent)) {
138		err = PTR_ERR(np->parent);
139		goto out_err;
140	}
141
142	err = notifier_call_chain(&pSeries_reconfig_chain,
143				  PSERIES_RECONFIG_ADD, np);
144	if (err == NOTIFY_BAD) {
145		printk(KERN_ERR "Failed to add device node %s\n", path);
146		err = -ENOMEM; /* For now, safe to assume kmalloc failure */
147		goto out_err;
148	}
149
150	of_attach_node(np);
151
152	add_node_proc_entries(np);
153
154	of_node_put(np->parent);
155
156	return 0;
157
158out_err:
159	if (np) {
160		of_node_put(np->parent);
161		kfree(np->full_name);
162		kfree(np);
163	}
164	return err;
165}
166
167static int pSeries_reconfig_remove_node(struct device_node *np)
168{
169	struct device_node *parent, *child;
170
171	parent = of_get_parent(np);
172	if (!parent)
173		return -EINVAL;
174
175	if ((child = of_get_next_child(np, NULL))) {
176		of_node_put(child);
177		return -EBUSY;
178	}
179
180	remove_node_proc_entries(np);
181
182	notifier_call_chain(&pSeries_reconfig_chain,
183			    PSERIES_RECONFIG_REMOVE, np);
184	of_detach_node(np);
185
186	of_node_put(parent);
187	of_node_put(np); /* Must decrement the refcount */
188	return 0;
189}
190
191/*
192 * /proc/ppc64/ofdt - yucky binary interface for adding and removing
193 * OF device nodes.  Should be deprecated as soon as we get an
194 * in-kernel wrapper for the RTAS ibm,configure-connector call.
195 */
196
197static void release_prop_list(const struct property *prop)
198{
199	struct property *next;
200	for (; prop; prop = next) {
201		next = prop->next;
202		kfree(prop->name);
203		kfree(prop->value);
204		kfree(prop);
205	}
206
207}
208
209/**
210 * parse_next_property - process the next property from raw input buffer
211 * @buf: input buffer, must be nul-terminated
212 * @end: end of the input buffer + 1, for validation
213 * @name: return value; set to property name in buf
214 * @length: return value; set to length of value
215 * @value: return value; set to the property value in buf
216 *
217 * Note that the caller must make copies of the name and value returned,
218 * this function does no allocation or copying of the data.  Return value
219 * is set to the next name in buf, or NULL on error.
220 */
221static char * parse_next_property(char *buf, char *end, char **name, int *length,
222				  unsigned char **value)
223{
224	char *tmp;
225
226	*name = buf;
227
228	tmp = strchr(buf, ' ');
229	if (!tmp) {
230		printk(KERN_ERR "property parse failed in %s at line %d\n",
231		       __FUNCTION__, __LINE__);
232		return NULL;
233	}
234	*tmp = '\0';
235
236	if (++tmp >= end) {
237		printk(KERN_ERR "property parse failed in %s at line %d\n",
238		       __FUNCTION__, __LINE__);
239		return NULL;
240	}
241
242	/* now we're on the length */
243	*length = -1;
244	*length = simple_strtoul(tmp, &tmp, 10);
245	if (*length == -1) {
246		printk(KERN_ERR "property parse failed in %s at line %d\n",
247		       __FUNCTION__, __LINE__);
248		return NULL;
249	}
250	if (*tmp != ' ' || ++tmp >= end) {
251		printk(KERN_ERR "property parse failed in %s at line %d\n",
252		       __FUNCTION__, __LINE__);
253		return NULL;
254	}
255
256	/* now we're on the value */
257	*value = tmp;
258	tmp += *length;
259	if (tmp > end) {
260		printk(KERN_ERR "property parse failed in %s at line %d\n",
261		       __FUNCTION__, __LINE__);
262		return NULL;
263	}
264	else if (tmp < end && *tmp != ' ' && *tmp != '\0') {
265		printk(KERN_ERR "property parse failed in %s at line %d\n",
266		       __FUNCTION__, __LINE__);
267		return NULL;
268	}
269	tmp++;
270
271	/* and now we should be on the next name, or the end */
272	return tmp;
273}
274
275static struct property *new_property(const char *name, const int length,
276				     const unsigned char *value, struct property *last)
277{
278	struct property *new = kmalloc(sizeof(*new), GFP_KERNEL);
279
280	if (!new)
281		return NULL;
282	memset(new, 0, sizeof(*new));
283
284	if (!(new->name = kmalloc(strlen(name) + 1, GFP_KERNEL)))
285		goto cleanup;
286	if (!(new->value = kmalloc(length + 1, GFP_KERNEL)))
287		goto cleanup;
288
289	strcpy(new->name, name);
290	memcpy(new->value, value, length);
291	*(((char *)new->value) + length) = 0;
292	new->length = length;
293	new->next = last;
294	return new;
295
296cleanup:
297	if (new->name)
298		kfree(new->name);
299	if (new->value)
300		kfree(new->value);
301	kfree(new);
302	return NULL;
303}
304
305static int do_add_node(char *buf, size_t bufsize)
306{
307	char *path, *end, *name;
308	struct device_node *np;
309	struct property *prop = NULL;
310	unsigned char* value;
311	int length, rv = 0;
312
313	end = buf + bufsize;
314	path = buf;
315	buf = strchr(buf, ' ');
316	if (!buf)
317		return -EINVAL;
318	*buf = '\0';
319	buf++;
320
321	if ((np = of_find_node_by_path(path))) {
322		of_node_put(np);
323		return -EINVAL;
324	}
325
326	/* rv = build_prop_list(tmp, bufsize - (tmp - buf), &proplist); */
327	while (buf < end &&
328	       (buf = parse_next_property(buf, end, &name, &length, &value))) {
329		struct property *last = prop;
330
331		prop = new_property(name, length, value, last);
332		if (!prop) {
333			rv = -ENOMEM;
334			prop = last;
335			goto out;
336		}
337	}
338	if (!buf) {
339		rv = -EINVAL;
340		goto out;
341	}
342
343	rv = pSeries_reconfig_add_node(path, prop);
344
345out:
346	if (rv)
347		release_prop_list(prop);
348	return rv;
349}
350
351static int do_remove_node(char *buf)
352{
353	struct device_node *node;
354	int rv = -ENODEV;
355
356	if ((node = of_find_node_by_path(buf)))
357		rv = pSeries_reconfig_remove_node(node);
358
359	of_node_put(node);
360	return rv;
361}
362
363/**
364 * ofdt_write - perform operations on the Open Firmware device tree
365 *
366 * @file: not used
367 * @buf: command and arguments
368 * @count: size of the command buffer
369 * @off: not used
370 *
371 * Operations supported at this time are addition and removal of
372 * whole nodes along with their properties.  Operations on individual
373 * properties are not implemented (yet).
374 */
375static ssize_t ofdt_write(struct file *file, const char __user *buf, size_t count,
376			  loff_t *off)
377{
378	int rv = 0;
379	char *kbuf;
380	char *tmp;
381
382	if (!(kbuf = kmalloc(count + 1, GFP_KERNEL))) {
383		rv = -ENOMEM;
384		goto out;
385	}
386	if (copy_from_user(kbuf, buf, count)) {
387		rv = -EFAULT;
388		goto out;
389	}
390
391	kbuf[count] = '\0';
392
393	tmp = strchr(kbuf, ' ');
394	if (!tmp) {
395		rv = -EINVAL;
396		goto out;
397	}
398	*tmp = '\0';
399	tmp++;
400
401	if (!strcmp(kbuf, "add_node"))
402		rv = do_add_node(tmp, count - (tmp - kbuf));
403	else if (!strcmp(kbuf, "remove_node"))
404		rv = do_remove_node(tmp);
405	else
406		rv = -EINVAL;
407out:
408	kfree(kbuf);
409	return rv ? rv : count;
410}
411
412static struct file_operations ofdt_fops = {
413	.write = ofdt_write
414};
415
416/* create /proc/ppc64/ofdt write-only by root */
417static int proc_ppc64_create_ofdt(void)
418{
419	struct proc_dir_entry *ent;
420
421	if (!(systemcfg->platform & PLATFORM_PSERIES))
422		return 0;
423
424	ent = create_proc_entry("ppc64/ofdt", S_IWUSR, NULL);
425	if (ent) {
426		ent->nlink = 1;
427		ent->data = NULL;
428		ent->size = 0;
429		ent->proc_fops = &ofdt_fops;
430	}
431
432	return 0;
433}
434__initcall(proc_ppc64_create_ofdt);