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75f3e8e4 GS |
1 | /* |
2 | * drivers/firmware/qemu_fw_cfg.c | |
3 | * | |
4 | * Copyright 2015 Carnegie Mellon University | |
5 | * | |
6 | * Expose entries from QEMU's firmware configuration (fw_cfg) device in | |
7 | * sysfs (read-only, under "/sys/firmware/qemu_fw_cfg/..."). | |
8 | * | |
9 | * The fw_cfg device may be instantiated via either an ACPI node (on x86 | |
10 | * and select subsets of aarch64), a Device Tree node (on arm), or using | |
11 | * a kernel module (or command line) parameter with the following syntax: | |
12 | * | |
13 | * [fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>] | |
14 | * or | |
15 | * [fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>] | |
16 | * | |
17 | * where: | |
18 | * <size> := size of ioport or mmio range | |
19 | * <base> := physical base address of ioport or mmio range | |
20 | * <ctrl_off> := (optional) offset of control register | |
21 | * <data_off> := (optional) offset of data register | |
22 | * | |
23 | * e.g.: | |
24 | * fw_cfg.ioport=2@0x510:0:1 (the default on x86) | |
25 | * or | |
26 | * fw_cfg.mmio=0xA@0x9020000:8:0 (the default on arm) | |
27 | */ | |
28 | ||
29 | #include <linux/module.h> | |
30 | #include <linux/platform_device.h> | |
31 | #include <linux/acpi.h> | |
32 | #include <linux/slab.h> | |
33 | #include <linux/io.h> | |
34 | #include <linux/ioport.h> | |
35 | ||
36 | MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>"); | |
37 | MODULE_DESCRIPTION("QEMU fw_cfg sysfs support"); | |
38 | MODULE_LICENSE("GPL"); | |
39 | ||
40 | /* selector key values for "well-known" fw_cfg entries */ | |
41 | #define FW_CFG_SIGNATURE 0x00 | |
42 | #define FW_CFG_ID 0x01 | |
43 | #define FW_CFG_FILE_DIR 0x19 | |
44 | ||
45 | /* size in bytes of fw_cfg signature */ | |
46 | #define FW_CFG_SIG_SIZE 4 | |
47 | ||
48 | /* fw_cfg "file name" is up to 56 characters (including terminating nul) */ | |
49 | #define FW_CFG_MAX_FILE_PATH 56 | |
50 | ||
51 | /* fw_cfg file directory entry type */ | |
52 | struct fw_cfg_file { | |
53 | u32 size; | |
54 | u16 select; | |
55 | u16 reserved; | |
56 | char name[FW_CFG_MAX_FILE_PATH]; | |
57 | }; | |
58 | ||
59 | /* fw_cfg device i/o register addresses */ | |
60 | static bool fw_cfg_is_mmio; | |
61 | static phys_addr_t fw_cfg_p_base; | |
62 | static resource_size_t fw_cfg_p_size; | |
63 | static void __iomem *fw_cfg_dev_base; | |
64 | static void __iomem *fw_cfg_reg_ctrl; | |
65 | static void __iomem *fw_cfg_reg_data; | |
66 | ||
67 | /* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */ | |
68 | static DEFINE_MUTEX(fw_cfg_dev_lock); | |
69 | ||
70 | /* pick appropriate endianness for selector key */ | |
71 | static inline u16 fw_cfg_sel_endianness(u16 key) | |
72 | { | |
73 | return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key); | |
74 | } | |
75 | ||
76 | /* read chunk of given fw_cfg blob (caller responsible for sanity-check) */ | |
77 | static inline void fw_cfg_read_blob(u16 key, | |
78 | void *buf, loff_t pos, size_t count) | |
79 | { | |
d4f6e272 | 80 | u32 glk = -1U; |
def7ac80 GS |
81 | acpi_status status; |
82 | ||
83 | /* If we have ACPI, ensure mutual exclusion against any potential | |
84 | * device access by the firmware, e.g. via AML methods: | |
85 | */ | |
86 | status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk); | |
87 | if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) { | |
88 | /* Should never get here */ | |
89 | WARN(1, "fw_cfg_read_blob: Failed to lock ACPI!\n"); | |
90 | memset(buf, 0, count); | |
91 | return; | |
92 | } | |
93 | ||
75f3e8e4 GS |
94 | mutex_lock(&fw_cfg_dev_lock); |
95 | iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl); | |
96 | while (pos-- > 0) | |
97 | ioread8(fw_cfg_reg_data); | |
98 | ioread8_rep(fw_cfg_reg_data, buf, count); | |
99 | mutex_unlock(&fw_cfg_dev_lock); | |
def7ac80 GS |
100 | |
101 | acpi_release_global_lock(glk); | |
75f3e8e4 GS |
102 | } |
103 | ||
104 | /* clean up fw_cfg device i/o */ | |
105 | static void fw_cfg_io_cleanup(void) | |
106 | { | |
107 | if (fw_cfg_is_mmio) { | |
108 | iounmap(fw_cfg_dev_base); | |
109 | release_mem_region(fw_cfg_p_base, fw_cfg_p_size); | |
110 | } else { | |
111 | ioport_unmap(fw_cfg_dev_base); | |
112 | release_region(fw_cfg_p_base, fw_cfg_p_size); | |
113 | } | |
114 | } | |
115 | ||
116 | /* arch-specific ctrl & data register offsets are not available in ACPI, DT */ | |
9b3ec23a | 117 | #if !(defined(FW_CFG_CTRL_OFF) && defined(FW_CFG_DATA_OFF)) |
75f3e8e4 GS |
118 | # if (defined(CONFIG_ARM) || defined(CONFIG_ARM64)) |
119 | # define FW_CFG_CTRL_OFF 0x08 | |
120 | # define FW_CFG_DATA_OFF 0x00 | |
121 | # elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */ | |
122 | # define FW_CFG_CTRL_OFF 0x00 | |
123 | # define FW_CFG_DATA_OFF 0x02 | |
124 | # elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */ | |
125 | # define FW_CFG_CTRL_OFF 0x00 | |
126 | # define FW_CFG_DATA_OFF 0x01 | |
127 | # else | |
00411b7b | 128 | # error "QEMU FW_CFG not available on this architecture!" |
75f3e8e4 GS |
129 | # endif |
130 | #endif | |
131 | ||
132 | /* initialize fw_cfg device i/o from platform data */ | |
133 | static int fw_cfg_do_platform_probe(struct platform_device *pdev) | |
134 | { | |
135 | char sig[FW_CFG_SIG_SIZE]; | |
136 | struct resource *range, *ctrl, *data; | |
137 | ||
138 | /* acquire i/o range details */ | |
139 | fw_cfg_is_mmio = false; | |
140 | range = platform_get_resource(pdev, IORESOURCE_IO, 0); | |
141 | if (!range) { | |
142 | fw_cfg_is_mmio = true; | |
143 | range = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
144 | if (!range) | |
145 | return -EINVAL; | |
146 | } | |
147 | fw_cfg_p_base = range->start; | |
148 | fw_cfg_p_size = resource_size(range); | |
149 | ||
150 | if (fw_cfg_is_mmio) { | |
151 | if (!request_mem_region(fw_cfg_p_base, | |
152 | fw_cfg_p_size, "fw_cfg_mem")) | |
153 | return -EBUSY; | |
154 | fw_cfg_dev_base = ioremap(fw_cfg_p_base, fw_cfg_p_size); | |
155 | if (!fw_cfg_dev_base) { | |
156 | release_mem_region(fw_cfg_p_base, fw_cfg_p_size); | |
157 | return -EFAULT; | |
158 | } | |
159 | } else { | |
160 | if (!request_region(fw_cfg_p_base, | |
161 | fw_cfg_p_size, "fw_cfg_io")) | |
162 | return -EBUSY; | |
163 | fw_cfg_dev_base = ioport_map(fw_cfg_p_base, fw_cfg_p_size); | |
164 | if (!fw_cfg_dev_base) { | |
165 | release_region(fw_cfg_p_base, fw_cfg_p_size); | |
166 | return -EFAULT; | |
167 | } | |
168 | } | |
169 | ||
170 | /* were custom register offsets provided (e.g. on the command line)? */ | |
171 | ctrl = platform_get_resource_byname(pdev, IORESOURCE_REG, "ctrl"); | |
172 | data = platform_get_resource_byname(pdev, IORESOURCE_REG, "data"); | |
173 | if (ctrl && data) { | |
174 | fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start; | |
175 | fw_cfg_reg_data = fw_cfg_dev_base + data->start; | |
176 | } else { | |
177 | /* use architecture-specific offsets */ | |
178 | fw_cfg_reg_ctrl = fw_cfg_dev_base + FW_CFG_CTRL_OFF; | |
179 | fw_cfg_reg_data = fw_cfg_dev_base + FW_CFG_DATA_OFF; | |
180 | } | |
181 | ||
182 | /* verify fw_cfg device signature */ | |
183 | fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 0, FW_CFG_SIG_SIZE); | |
184 | if (memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) { | |
185 | fw_cfg_io_cleanup(); | |
186 | return -ENODEV; | |
187 | } | |
188 | ||
189 | return 0; | |
190 | } | |
191 | ||
192 | /* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */ | |
193 | static u32 fw_cfg_rev; | |
194 | ||
195 | static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf) | |
196 | { | |
197 | return sprintf(buf, "%u\n", fw_cfg_rev); | |
198 | } | |
199 | ||
200 | static const struct { | |
201 | struct attribute attr; | |
202 | ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf); | |
203 | } fw_cfg_rev_attr = { | |
204 | .attr = { .name = "rev", .mode = S_IRUSR }, | |
205 | .show = fw_cfg_showrev, | |
206 | }; | |
207 | ||
208 | /* fw_cfg_sysfs_entry type */ | |
209 | struct fw_cfg_sysfs_entry { | |
210 | struct kobject kobj; | |
211 | struct fw_cfg_file f; | |
212 | struct list_head list; | |
213 | }; | |
214 | ||
215 | /* get fw_cfg_sysfs_entry from kobject member */ | |
216 | static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj) | |
217 | { | |
218 | return container_of(kobj, struct fw_cfg_sysfs_entry, kobj); | |
219 | } | |
220 | ||
221 | /* fw_cfg_sysfs_attribute type */ | |
222 | struct fw_cfg_sysfs_attribute { | |
223 | struct attribute attr; | |
224 | ssize_t (*show)(struct fw_cfg_sysfs_entry *entry, char *buf); | |
225 | }; | |
226 | ||
227 | /* get fw_cfg_sysfs_attribute from attribute member */ | |
228 | static inline struct fw_cfg_sysfs_attribute *to_attr(struct attribute *attr) | |
229 | { | |
230 | return container_of(attr, struct fw_cfg_sysfs_attribute, attr); | |
231 | } | |
232 | ||
233 | /* global cache of fw_cfg_sysfs_entry objects */ | |
234 | static LIST_HEAD(fw_cfg_entry_cache); | |
235 | ||
236 | /* kobjects removed lazily by kernel, mutual exclusion needed */ | |
237 | static DEFINE_SPINLOCK(fw_cfg_cache_lock); | |
238 | ||
239 | static inline void fw_cfg_sysfs_cache_enlist(struct fw_cfg_sysfs_entry *entry) | |
240 | { | |
241 | spin_lock(&fw_cfg_cache_lock); | |
242 | list_add_tail(&entry->list, &fw_cfg_entry_cache); | |
243 | spin_unlock(&fw_cfg_cache_lock); | |
244 | } | |
245 | ||
246 | static inline void fw_cfg_sysfs_cache_delist(struct fw_cfg_sysfs_entry *entry) | |
247 | { | |
248 | spin_lock(&fw_cfg_cache_lock); | |
249 | list_del(&entry->list); | |
250 | spin_unlock(&fw_cfg_cache_lock); | |
251 | } | |
252 | ||
253 | static void fw_cfg_sysfs_cache_cleanup(void) | |
254 | { | |
255 | struct fw_cfg_sysfs_entry *entry, *next; | |
256 | ||
257 | list_for_each_entry_safe(entry, next, &fw_cfg_entry_cache, list) { | |
258 | /* will end up invoking fw_cfg_sysfs_cache_delist() | |
259 | * via each object's release() method (i.e. destructor) | |
260 | */ | |
261 | kobject_put(&entry->kobj); | |
262 | } | |
263 | } | |
264 | ||
265 | /* default_attrs: per-entry attributes and show methods */ | |
266 | ||
267 | #define FW_CFG_SYSFS_ATTR(_attr) \ | |
268 | struct fw_cfg_sysfs_attribute fw_cfg_sysfs_attr_##_attr = { \ | |
269 | .attr = { .name = __stringify(_attr), .mode = S_IRUSR }, \ | |
270 | .show = fw_cfg_sysfs_show_##_attr, \ | |
271 | } | |
272 | ||
273 | static ssize_t fw_cfg_sysfs_show_size(struct fw_cfg_sysfs_entry *e, char *buf) | |
274 | { | |
275 | return sprintf(buf, "%u\n", e->f.size); | |
276 | } | |
277 | ||
278 | static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf) | |
279 | { | |
280 | return sprintf(buf, "%u\n", e->f.select); | |
281 | } | |
282 | ||
283 | static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf) | |
284 | { | |
285 | return sprintf(buf, "%s\n", e->f.name); | |
286 | } | |
287 | ||
288 | static FW_CFG_SYSFS_ATTR(size); | |
289 | static FW_CFG_SYSFS_ATTR(key); | |
290 | static FW_CFG_SYSFS_ATTR(name); | |
291 | ||
292 | static struct attribute *fw_cfg_sysfs_entry_attrs[] = { | |
293 | &fw_cfg_sysfs_attr_size.attr, | |
294 | &fw_cfg_sysfs_attr_key.attr, | |
295 | &fw_cfg_sysfs_attr_name.attr, | |
296 | NULL, | |
297 | }; | |
298 | ||
299 | /* sysfs_ops: find fw_cfg_[entry, attribute] and call appropriate show method */ | |
300 | static ssize_t fw_cfg_sysfs_attr_show(struct kobject *kobj, struct attribute *a, | |
301 | char *buf) | |
302 | { | |
303 | struct fw_cfg_sysfs_entry *entry = to_entry(kobj); | |
304 | struct fw_cfg_sysfs_attribute *attr = to_attr(a); | |
305 | ||
306 | return attr->show(entry, buf); | |
307 | } | |
308 | ||
309 | static const struct sysfs_ops fw_cfg_sysfs_attr_ops = { | |
310 | .show = fw_cfg_sysfs_attr_show, | |
311 | }; | |
312 | ||
313 | /* release: destructor, to be called via kobject_put() */ | |
314 | static void fw_cfg_sysfs_release_entry(struct kobject *kobj) | |
315 | { | |
316 | struct fw_cfg_sysfs_entry *entry = to_entry(kobj); | |
317 | ||
318 | fw_cfg_sysfs_cache_delist(entry); | |
319 | kfree(entry); | |
320 | } | |
321 | ||
322 | /* kobj_type: ties together all properties required to register an entry */ | |
323 | static struct kobj_type fw_cfg_sysfs_entry_ktype = { | |
324 | .default_attrs = fw_cfg_sysfs_entry_attrs, | |
325 | .sysfs_ops = &fw_cfg_sysfs_attr_ops, | |
326 | .release = fw_cfg_sysfs_release_entry, | |
327 | }; | |
328 | ||
329 | /* raw-read method and attribute */ | |
330 | static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj, | |
331 | struct bin_attribute *bin_attr, | |
332 | char *buf, loff_t pos, size_t count) | |
333 | { | |
334 | struct fw_cfg_sysfs_entry *entry = to_entry(kobj); | |
335 | ||
336 | if (pos > entry->f.size) | |
337 | return -EINVAL; | |
338 | ||
339 | if (count > entry->f.size - pos) | |
340 | count = entry->f.size - pos; | |
341 | ||
342 | fw_cfg_read_blob(entry->f.select, buf, pos, count); | |
343 | return count; | |
344 | } | |
345 | ||
346 | static struct bin_attribute fw_cfg_sysfs_attr_raw = { | |
347 | .attr = { .name = "raw", .mode = S_IRUSR }, | |
348 | .read = fw_cfg_sysfs_read_raw, | |
349 | }; | |
350 | ||
246c46eb GS |
351 | /* |
352 | * Create a kset subdirectory matching each '/' delimited dirname token | |
353 | * in 'name', starting with sysfs kset/folder 'dir'; At the end, create | |
354 | * a symlink directed at the given 'target'. | |
355 | * NOTE: We do this on a best-effort basis, since 'name' is not guaranteed | |
356 | * to be a well-behaved path name. Whenever a symlink vs. kset directory | |
357 | * name collision occurs, the kernel will issue big scary warnings while | |
358 | * refusing to add the offending link or directory. We follow up with our | |
359 | * own, slightly less scary error messages explaining the situation :) | |
360 | */ | |
361 | static int fw_cfg_build_symlink(struct kset *dir, | |
362 | struct kobject *target, const char *name) | |
363 | { | |
364 | int ret; | |
365 | struct kset *subdir; | |
366 | struct kobject *ko; | |
367 | char *name_copy, *p, *tok; | |
368 | ||
369 | if (!dir || !target || !name || !*name) | |
370 | return -EINVAL; | |
371 | ||
372 | /* clone a copy of name for parsing */ | |
373 | name_copy = p = kstrdup(name, GFP_KERNEL); | |
374 | if (!name_copy) | |
375 | return -ENOMEM; | |
376 | ||
377 | /* create folders for each dirname token, then symlink for basename */ | |
378 | while ((tok = strsep(&p, "/")) && *tok) { | |
379 | ||
380 | /* last (basename) token? If so, add symlink here */ | |
381 | if (!p || !*p) { | |
382 | ret = sysfs_create_link(&dir->kobj, target, tok); | |
383 | break; | |
384 | } | |
385 | ||
386 | /* does the current dir contain an item named after tok ? */ | |
387 | ko = kset_find_obj(dir, tok); | |
388 | if (ko) { | |
389 | /* drop reference added by kset_find_obj */ | |
390 | kobject_put(ko); | |
391 | ||
392 | /* ko MUST be a kset - we're about to use it as one ! */ | |
393 | if (ko->ktype != dir->kobj.ktype) { | |
394 | ret = -EINVAL; | |
395 | break; | |
396 | } | |
397 | ||
398 | /* descend into already existing subdirectory */ | |
399 | dir = to_kset(ko); | |
400 | } else { | |
401 | /* create new subdirectory kset */ | |
402 | subdir = kzalloc(sizeof(struct kset), GFP_KERNEL); | |
403 | if (!subdir) { | |
404 | ret = -ENOMEM; | |
405 | break; | |
406 | } | |
407 | subdir->kobj.kset = dir; | |
408 | subdir->kobj.ktype = dir->kobj.ktype; | |
409 | ret = kobject_set_name(&subdir->kobj, "%s", tok); | |
410 | if (ret) { | |
411 | kfree(subdir); | |
412 | break; | |
413 | } | |
414 | ret = kset_register(subdir); | |
415 | if (ret) { | |
416 | kfree(subdir); | |
417 | break; | |
418 | } | |
419 | ||
420 | /* descend into newly created subdirectory */ | |
421 | dir = subdir; | |
422 | } | |
423 | } | |
424 | ||
425 | /* we're done with cloned copy of name */ | |
426 | kfree(name_copy); | |
427 | return ret; | |
428 | } | |
429 | ||
430 | /* recursively unregister fw_cfg/by_name/ kset directory tree */ | |
431 | static void fw_cfg_kset_unregister_recursive(struct kset *kset) | |
432 | { | |
433 | struct kobject *k, *next; | |
434 | ||
435 | list_for_each_entry_safe(k, next, &kset->list, entry) | |
436 | /* all set members are ksets too, but check just in case... */ | |
437 | if (k->ktype == kset->kobj.ktype) | |
438 | fw_cfg_kset_unregister_recursive(to_kset(k)); | |
439 | ||
440 | /* symlinks are cleanly and automatically removed with the directory */ | |
441 | kset_unregister(kset); | |
442 | } | |
443 | ||
444 | /* kobjects & kset representing top-level, by_key, and by_name folders */ | |
75f3e8e4 GS |
445 | static struct kobject *fw_cfg_top_ko; |
446 | static struct kobject *fw_cfg_sel_ko; | |
246c46eb | 447 | static struct kset *fw_cfg_fname_kset; |
75f3e8e4 GS |
448 | |
449 | /* register an individual fw_cfg file */ | |
450 | static int fw_cfg_register_file(const struct fw_cfg_file *f) | |
451 | { | |
452 | int err; | |
453 | struct fw_cfg_sysfs_entry *entry; | |
454 | ||
455 | /* allocate new entry */ | |
456 | entry = kzalloc(sizeof(*entry), GFP_KERNEL); | |
457 | if (!entry) | |
458 | return -ENOMEM; | |
459 | ||
460 | /* set file entry information */ | |
461 | memcpy(&entry->f, f, sizeof(struct fw_cfg_file)); | |
462 | ||
463 | /* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */ | |
464 | err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype, | |
465 | fw_cfg_sel_ko, "%d", entry->f.select); | |
466 | if (err) | |
467 | goto err_register; | |
468 | ||
469 | /* add raw binary content access */ | |
470 | err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw); | |
471 | if (err) | |
472 | goto err_add_raw; | |
473 | ||
246c46eb GS |
474 | /* try adding "/sys/firmware/qemu_fw_cfg/by_name/" symlink */ |
475 | fw_cfg_build_symlink(fw_cfg_fname_kset, &entry->kobj, entry->f.name); | |
476 | ||
75f3e8e4 GS |
477 | /* success, add entry to global cache */ |
478 | fw_cfg_sysfs_cache_enlist(entry); | |
479 | return 0; | |
480 | ||
481 | err_add_raw: | |
482 | kobject_del(&entry->kobj); | |
483 | err_register: | |
484 | kfree(entry); | |
485 | return err; | |
486 | } | |
487 | ||
488 | /* iterate over all fw_cfg directory entries, registering each one */ | |
489 | static int fw_cfg_register_dir_entries(void) | |
490 | { | |
491 | int ret = 0; | |
492 | u32 count, i; | |
493 | struct fw_cfg_file *dir; | |
494 | size_t dir_size; | |
495 | ||
496 | fw_cfg_read_blob(FW_CFG_FILE_DIR, &count, 0, sizeof(count)); | |
497 | count = be32_to_cpu(count); | |
498 | dir_size = count * sizeof(struct fw_cfg_file); | |
499 | ||
500 | dir = kmalloc(dir_size, GFP_KERNEL); | |
501 | if (!dir) | |
502 | return -ENOMEM; | |
503 | ||
504 | fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, sizeof(count), dir_size); | |
505 | ||
506 | for (i = 0; i < count; i++) { | |
507 | dir[i].size = be32_to_cpu(dir[i].size); | |
508 | dir[i].select = be16_to_cpu(dir[i].select); | |
509 | ret = fw_cfg_register_file(&dir[i]); | |
510 | if (ret) | |
511 | break; | |
512 | } | |
513 | ||
514 | kfree(dir); | |
515 | return ret; | |
516 | } | |
517 | ||
518 | /* unregister top-level or by_key folder */ | |
519 | static inline void fw_cfg_kobj_cleanup(struct kobject *kobj) | |
520 | { | |
521 | kobject_del(kobj); | |
522 | kobject_put(kobj); | |
523 | } | |
524 | ||
525 | static int fw_cfg_sysfs_probe(struct platform_device *pdev) | |
526 | { | |
527 | int err; | |
528 | ||
529 | /* NOTE: If we supported multiple fw_cfg devices, we'd first create | |
530 | * a subdirectory named after e.g. pdev->id, then hang per-device | |
246c46eb | 531 | * by_key (and by_name) subdirectories underneath it. However, only |
75f3e8e4 GS |
532 | * one fw_cfg device exist system-wide, so if one was already found |
533 | * earlier, we might as well stop here. | |
534 | */ | |
535 | if (fw_cfg_sel_ko) | |
536 | return -EBUSY; | |
537 | ||
246c46eb | 538 | /* create by_key and by_name subdirs of /sys/firmware/qemu_fw_cfg/ */ |
75f3e8e4 GS |
539 | err = -ENOMEM; |
540 | fw_cfg_sel_ko = kobject_create_and_add("by_key", fw_cfg_top_ko); | |
541 | if (!fw_cfg_sel_ko) | |
542 | goto err_sel; | |
246c46eb GS |
543 | fw_cfg_fname_kset = kset_create_and_add("by_name", NULL, fw_cfg_top_ko); |
544 | if (!fw_cfg_fname_kset) | |
545 | goto err_name; | |
75f3e8e4 GS |
546 | |
547 | /* initialize fw_cfg device i/o from platform data */ | |
548 | err = fw_cfg_do_platform_probe(pdev); | |
549 | if (err) | |
550 | goto err_probe; | |
551 | ||
552 | /* get revision number, add matching top-level attribute */ | |
553 | fw_cfg_read_blob(FW_CFG_ID, &fw_cfg_rev, 0, sizeof(fw_cfg_rev)); | |
554 | fw_cfg_rev = le32_to_cpu(fw_cfg_rev); | |
555 | err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); | |
556 | if (err) | |
557 | goto err_rev; | |
558 | ||
559 | /* process fw_cfg file directory entry, registering each file */ | |
560 | err = fw_cfg_register_dir_entries(); | |
561 | if (err) | |
562 | goto err_dir; | |
563 | ||
564 | /* success */ | |
565 | pr_debug("fw_cfg: loaded.\n"); | |
566 | return 0; | |
567 | ||
568 | err_dir: | |
569 | fw_cfg_sysfs_cache_cleanup(); | |
570 | sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr); | |
571 | err_rev: | |
572 | fw_cfg_io_cleanup(); | |
573 | err_probe: | |
246c46eb GS |
574 | fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset); |
575 | err_name: | |
75f3e8e4 GS |
576 | fw_cfg_kobj_cleanup(fw_cfg_sel_ko); |
577 | err_sel: | |
578 | return err; | |
579 | } | |
580 | ||
581 | static int fw_cfg_sysfs_remove(struct platform_device *pdev) | |
582 | { | |
583 | pr_debug("fw_cfg: unloading.\n"); | |
584 | fw_cfg_sysfs_cache_cleanup(); | |
246c46eb | 585 | fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset); |
75f3e8e4 GS |
586 | fw_cfg_kobj_cleanup(fw_cfg_sel_ko); |
587 | fw_cfg_io_cleanup(); | |
588 | return 0; | |
589 | } | |
590 | ||
591 | static const struct of_device_id fw_cfg_sysfs_mmio_match[] = { | |
592 | { .compatible = "qemu,fw-cfg-mmio", }, | |
593 | {}, | |
594 | }; | |
595 | MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match); | |
596 | ||
597 | #ifdef CONFIG_ACPI | |
598 | static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = { | |
599 | { "QEMU0002", }, | |
600 | {}, | |
601 | }; | |
602 | MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match); | |
603 | #endif | |
604 | ||
605 | static struct platform_driver fw_cfg_sysfs_driver = { | |
606 | .probe = fw_cfg_sysfs_probe, | |
607 | .remove = fw_cfg_sysfs_remove, | |
608 | .driver = { | |
609 | .name = "fw_cfg", | |
610 | .of_match_table = fw_cfg_sysfs_mmio_match, | |
611 | .acpi_match_table = ACPI_PTR(fw_cfg_sysfs_acpi_match), | |
612 | }, | |
613 | }; | |
614 | ||
615 | #ifdef CONFIG_FW_CFG_SYSFS_CMDLINE | |
616 | ||
617 | static struct platform_device *fw_cfg_cmdline_dev; | |
618 | ||
619 | /* this probably belongs in e.g. include/linux/types.h, | |
620 | * but right now we are the only ones doing it... | |
621 | */ | |
622 | #ifdef CONFIG_PHYS_ADDR_T_64BIT | |
623 | #define __PHYS_ADDR_PREFIX "ll" | |
624 | #else | |
625 | #define __PHYS_ADDR_PREFIX "" | |
626 | #endif | |
627 | ||
628 | /* use special scanf/printf modifier for phys_addr_t, resource_size_t */ | |
629 | #define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \ | |
630 | ":%" __PHYS_ADDR_PREFIX "i" \ | |
631 | ":%" __PHYS_ADDR_PREFIX "i%n" | |
632 | ||
633 | #define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \ | |
634 | "0x%" __PHYS_ADDR_PREFIX "x" | |
635 | ||
636 | #define PH_ADDR_PR_3_FMT PH_ADDR_PR_1_FMT \ | |
637 | ":%" __PHYS_ADDR_PREFIX "u" \ | |
638 | ":%" __PHYS_ADDR_PREFIX "u" | |
639 | ||
640 | static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp) | |
641 | { | |
642 | struct resource res[3] = {}; | |
643 | char *str; | |
644 | phys_addr_t base; | |
645 | resource_size_t size, ctrl_off, data_off; | |
646 | int processed, consumed = 0; | |
647 | ||
648 | /* only one fw_cfg device can exist system-wide, so if one | |
649 | * was processed on the command line already, we might as | |
650 | * well stop here. | |
651 | */ | |
652 | if (fw_cfg_cmdline_dev) { | |
653 | /* avoid leaking previously registered device */ | |
654 | platform_device_unregister(fw_cfg_cmdline_dev); | |
655 | return -EINVAL; | |
656 | } | |
657 | ||
658 | /* consume "<size>" portion of command line argument */ | |
659 | size = memparse(arg, &str); | |
660 | ||
661 | /* get "@<base>[:<ctrl_off>:<data_off>]" chunks */ | |
662 | processed = sscanf(str, PH_ADDR_SCAN_FMT, | |
663 | &base, &consumed, | |
664 | &ctrl_off, &data_off, &consumed); | |
665 | ||
666 | /* sscanf() must process precisely 1 or 3 chunks: | |
667 | * <base> is mandatory, optionally followed by <ctrl_off> | |
668 | * and <data_off>; | |
669 | * there must be no extra characters after the last chunk, | |
670 | * so str[consumed] must be '\0'. | |
671 | */ | |
672 | if (str[consumed] || | |
673 | (processed != 1 && processed != 3)) | |
674 | return -EINVAL; | |
675 | ||
676 | res[0].start = base; | |
677 | res[0].end = base + size - 1; | |
678 | res[0].flags = !strcmp(kp->name, "mmio") ? IORESOURCE_MEM : | |
679 | IORESOURCE_IO; | |
680 | ||
681 | /* insert register offsets, if provided */ | |
682 | if (processed > 1) { | |
683 | res[1].name = "ctrl"; | |
684 | res[1].start = ctrl_off; | |
685 | res[1].flags = IORESOURCE_REG; | |
686 | res[2].name = "data"; | |
687 | res[2].start = data_off; | |
688 | res[2].flags = IORESOURCE_REG; | |
689 | } | |
690 | ||
691 | /* "processed" happens to nicely match the number of resources | |
692 | * we need to pass in to this platform device. | |
693 | */ | |
694 | fw_cfg_cmdline_dev = platform_device_register_simple("fw_cfg", | |
695 | PLATFORM_DEVID_NONE, res, processed); | |
696 | if (IS_ERR(fw_cfg_cmdline_dev)) | |
697 | return PTR_ERR(fw_cfg_cmdline_dev); | |
698 | ||
699 | return 0; | |
700 | } | |
701 | ||
702 | static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp) | |
703 | { | |
704 | /* stay silent if device was not configured via the command | |
705 | * line, or if the parameter name (ioport/mmio) doesn't match | |
706 | * the device setting | |
707 | */ | |
708 | if (!fw_cfg_cmdline_dev || | |
709 | (!strcmp(kp->name, "mmio") ^ | |
710 | (fw_cfg_cmdline_dev->resource[0].flags == IORESOURCE_MEM))) | |
711 | return 0; | |
712 | ||
713 | switch (fw_cfg_cmdline_dev->num_resources) { | |
714 | case 1: | |
715 | return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_1_FMT, | |
716 | resource_size(&fw_cfg_cmdline_dev->resource[0]), | |
717 | fw_cfg_cmdline_dev->resource[0].start); | |
718 | case 3: | |
719 | return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_3_FMT, | |
720 | resource_size(&fw_cfg_cmdline_dev->resource[0]), | |
721 | fw_cfg_cmdline_dev->resource[0].start, | |
722 | fw_cfg_cmdline_dev->resource[1].start, | |
723 | fw_cfg_cmdline_dev->resource[2].start); | |
724 | } | |
725 | ||
726 | /* Should never get here */ | |
727 | WARN(1, "Unexpected number of resources: %d\n", | |
728 | fw_cfg_cmdline_dev->num_resources); | |
729 | return 0; | |
730 | } | |
731 | ||
732 | static const struct kernel_param_ops fw_cfg_cmdline_param_ops = { | |
733 | .set = fw_cfg_cmdline_set, | |
734 | .get = fw_cfg_cmdline_get, | |
735 | }; | |
736 | ||
737 | device_param_cb(ioport, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR); | |
738 | device_param_cb(mmio, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR); | |
739 | ||
740 | #endif /* CONFIG_FW_CFG_SYSFS_CMDLINE */ | |
741 | ||
742 | static int __init fw_cfg_sysfs_init(void) | |
743 | { | |
e8aabc64 MT |
744 | int ret; |
745 | ||
75f3e8e4 GS |
746 | /* create /sys/firmware/qemu_fw_cfg/ top level directory */ |
747 | fw_cfg_top_ko = kobject_create_and_add("qemu_fw_cfg", firmware_kobj); | |
748 | if (!fw_cfg_top_ko) | |
749 | return -ENOMEM; | |
750 | ||
e8aabc64 MT |
751 | ret = platform_driver_register(&fw_cfg_sysfs_driver); |
752 | if (ret) | |
753 | fw_cfg_kobj_cleanup(fw_cfg_top_ko); | |
754 | ||
755 | return ret; | |
75f3e8e4 GS |
756 | } |
757 | ||
758 | static void __exit fw_cfg_sysfs_exit(void) | |
759 | { | |
760 | platform_driver_unregister(&fw_cfg_sysfs_driver); | |
761 | ||
762 | #ifdef CONFIG_FW_CFG_SYSFS_CMDLINE | |
763 | platform_device_unregister(fw_cfg_cmdline_dev); | |
764 | #endif | |
765 | ||
766 | /* clean up /sys/firmware/qemu_fw_cfg/ */ | |
767 | fw_cfg_kobj_cleanup(fw_cfg_top_ko); | |
768 | } | |
769 | ||
770 | module_init(fw_cfg_sysfs_init); | |
771 | module_exit(fw_cfg_sysfs_exit); |