2 * drivers/firmware/qemu_fw_cfg.c
4 * Copyright 2015 Carnegie Mellon University
6 * Expose entries from QEMU's firmware configuration (fw_cfg) device in
7 * sysfs (read-only, under "/sys/firmware/qemu_fw_cfg/...").
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:
13 * [fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>]
15 * [fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>]
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
24 * fw_cfg.ioport=2@0x510:0:1 (the default on x86)
26 * fw_cfg.mmio=0xA@0x9020000:8:0 (the default on arm)
29 #include <linux/module.h>
30 #include <linux/platform_device.h>
31 #include <linux/acpi.h>
32 #include <linux/slab.h>
34 #include <linux/ioport.h>
36 MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>");
37 MODULE_DESCRIPTION("QEMU fw_cfg sysfs support");
38 MODULE_LICENSE("GPL");
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
45 /* size in bytes of fw_cfg signature */
46 #define FW_CFG_SIG_SIZE 4
48 /* fw_cfg "file name" is up to 56 characters (including terminating nul) */
49 #define FW_CFG_MAX_FILE_PATH 56
51 /* fw_cfg file directory entry type */
56 char name[FW_CFG_MAX_FILE_PATH];
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;
67 /* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */
68 static DEFINE_MUTEX(fw_cfg_dev_lock);
70 /* pick appropriate endianness for selector key */
71 static inline u16 fw_cfg_sel_endianness(u16 key)
73 return fw_cfg_is_mmio ? cpu_to_be16(key) : cpu_to_le16(key);
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)
83 /* If we have ACPI, ensure mutual exclusion against any potential
84 * device access by the firmware, e.g. via AML methods:
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);
94 mutex_lock(&fw_cfg_dev_lock);
95 iowrite16(fw_cfg_sel_endianness(key), fw_cfg_reg_ctrl);
97 ioread8(fw_cfg_reg_data);
98 ioread8_rep(fw_cfg_reg_data, buf, count);
99 mutex_unlock(&fw_cfg_dev_lock);
101 acpi_release_global_lock(glk);
104 /* clean up fw_cfg device i/o */
105 static void fw_cfg_io_cleanup(void)
107 if (fw_cfg_is_mmio) {
108 iounmap(fw_cfg_dev_base);
109 release_mem_region(fw_cfg_p_base, fw_cfg_p_size);
111 ioport_unmap(fw_cfg_dev_base);
112 release_region(fw_cfg_p_base, fw_cfg_p_size);
116 /* arch-specific ctrl & data register offsets are not available in ACPI, DT */
117 #if !(defined(FW_CFG_CTRL_OFF) && defined(FW_CFG_DATA_OFF))
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
128 # error "QEMU FW_CFG not available on this architecture!"
132 /* initialize fw_cfg device i/o from platform data */
133 static int fw_cfg_do_platform_probe(struct platform_device *pdev)
135 char sig[FW_CFG_SIG_SIZE];
136 struct resource *range, *ctrl, *data;
138 /* acquire i/o range details */
139 fw_cfg_is_mmio = false;
140 range = platform_get_resource(pdev, IORESOURCE_IO, 0);
142 fw_cfg_is_mmio = true;
143 range = platform_get_resource(pdev, IORESOURCE_MEM, 0);
147 fw_cfg_p_base = range->start;
148 fw_cfg_p_size = resource_size(range);
150 if (fw_cfg_is_mmio) {
151 if (!request_mem_region(fw_cfg_p_base,
152 fw_cfg_p_size, "fw_cfg_mem"))
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);
160 if (!request_region(fw_cfg_p_base,
161 fw_cfg_p_size, "fw_cfg_io"))
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);
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");
174 fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start;
175 fw_cfg_reg_data = fw_cfg_dev_base + data->start;
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;
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) {
192 /* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */
193 static u32 fw_cfg_rev;
195 static ssize_t fw_cfg_showrev(struct kobject *k, struct kobj_attribute *a,
198 return sprintf(buf, "%u\n", fw_cfg_rev);
201 static const struct kobj_attribute fw_cfg_rev_attr = {
202 .attr = { .name = "rev", .mode = S_IRUSR },
203 .show = fw_cfg_showrev,
206 /* fw_cfg_sysfs_entry type */
207 struct fw_cfg_sysfs_entry {
209 struct fw_cfg_file f;
210 struct list_head list;
213 /* get fw_cfg_sysfs_entry from kobject member */
214 static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj)
216 return container_of(kobj, struct fw_cfg_sysfs_entry, kobj);
219 /* fw_cfg_sysfs_attribute type */
220 struct fw_cfg_sysfs_attribute {
221 struct attribute attr;
222 ssize_t (*show)(struct fw_cfg_sysfs_entry *entry, char *buf);
225 /* get fw_cfg_sysfs_attribute from attribute member */
226 static inline struct fw_cfg_sysfs_attribute *to_attr(struct attribute *attr)
228 return container_of(attr, struct fw_cfg_sysfs_attribute, attr);
231 /* global cache of fw_cfg_sysfs_entry objects */
232 static LIST_HEAD(fw_cfg_entry_cache);
234 /* kobjects removed lazily by kernel, mutual exclusion needed */
235 static DEFINE_SPINLOCK(fw_cfg_cache_lock);
237 static inline void fw_cfg_sysfs_cache_enlist(struct fw_cfg_sysfs_entry *entry)
239 spin_lock(&fw_cfg_cache_lock);
240 list_add_tail(&entry->list, &fw_cfg_entry_cache);
241 spin_unlock(&fw_cfg_cache_lock);
244 static inline void fw_cfg_sysfs_cache_delist(struct fw_cfg_sysfs_entry *entry)
246 spin_lock(&fw_cfg_cache_lock);
247 list_del(&entry->list);
248 spin_unlock(&fw_cfg_cache_lock);
251 static void fw_cfg_sysfs_cache_cleanup(void)
253 struct fw_cfg_sysfs_entry *entry, *next;
255 list_for_each_entry_safe(entry, next, &fw_cfg_entry_cache, list) {
256 /* will end up invoking fw_cfg_sysfs_cache_delist()
257 * via each object's release() method (i.e. destructor)
259 kobject_put(&entry->kobj);
263 /* default_attrs: per-entry attributes and show methods */
265 #define FW_CFG_SYSFS_ATTR(_attr) \
266 struct fw_cfg_sysfs_attribute fw_cfg_sysfs_attr_##_attr = { \
267 .attr = { .name = __stringify(_attr), .mode = S_IRUSR }, \
268 .show = fw_cfg_sysfs_show_##_attr, \
271 static ssize_t fw_cfg_sysfs_show_size(struct fw_cfg_sysfs_entry *e, char *buf)
273 return sprintf(buf, "%u\n", e->f.size);
276 static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf)
278 return sprintf(buf, "%u\n", e->f.select);
281 static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf)
283 return sprintf(buf, "%s\n", e->f.name);
286 static FW_CFG_SYSFS_ATTR(size);
287 static FW_CFG_SYSFS_ATTR(key);
288 static FW_CFG_SYSFS_ATTR(name);
290 static struct attribute *fw_cfg_sysfs_entry_attrs[] = {
291 &fw_cfg_sysfs_attr_size.attr,
292 &fw_cfg_sysfs_attr_key.attr,
293 &fw_cfg_sysfs_attr_name.attr,
297 /* sysfs_ops: find fw_cfg_[entry, attribute] and call appropriate show method */
298 static ssize_t fw_cfg_sysfs_attr_show(struct kobject *kobj, struct attribute *a,
301 struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
302 struct fw_cfg_sysfs_attribute *attr = to_attr(a);
304 return attr->show(entry, buf);
307 static const struct sysfs_ops fw_cfg_sysfs_attr_ops = {
308 .show = fw_cfg_sysfs_attr_show,
311 /* release: destructor, to be called via kobject_put() */
312 static void fw_cfg_sysfs_release_entry(struct kobject *kobj)
314 struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
316 fw_cfg_sysfs_cache_delist(entry);
320 /* kobj_type: ties together all properties required to register an entry */
321 static struct kobj_type fw_cfg_sysfs_entry_ktype = {
322 .default_attrs = fw_cfg_sysfs_entry_attrs,
323 .sysfs_ops = &fw_cfg_sysfs_attr_ops,
324 .release = fw_cfg_sysfs_release_entry,
327 /* raw-read method and attribute */
328 static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
329 struct bin_attribute *bin_attr,
330 char *buf, loff_t pos, size_t count)
332 struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
334 if (pos > entry->f.size)
337 if (count > entry->f.size - pos)
338 count = entry->f.size - pos;
340 fw_cfg_read_blob(entry->f.select, buf, pos, count);
344 static struct bin_attribute fw_cfg_sysfs_attr_raw = {
345 .attr = { .name = "raw", .mode = S_IRUSR },
346 .read = fw_cfg_sysfs_read_raw,
350 * Create a kset subdirectory matching each '/' delimited dirname token
351 * in 'name', starting with sysfs kset/folder 'dir'; At the end, create
352 * a symlink directed at the given 'target'.
353 * NOTE: We do this on a best-effort basis, since 'name' is not guaranteed
354 * to be a well-behaved path name. Whenever a symlink vs. kset directory
355 * name collision occurs, the kernel will issue big scary warnings while
356 * refusing to add the offending link or directory. We follow up with our
357 * own, slightly less scary error messages explaining the situation :)
359 static int fw_cfg_build_symlink(struct kset *dir,
360 struct kobject *target, const char *name)
365 char *name_copy, *p, *tok;
367 if (!dir || !target || !name || !*name)
370 /* clone a copy of name for parsing */
371 name_copy = p = kstrdup(name, GFP_KERNEL);
375 /* create folders for each dirname token, then symlink for basename */
376 while ((tok = strsep(&p, "/")) && *tok) {
378 /* last (basename) token? If so, add symlink here */
380 ret = sysfs_create_link(&dir->kobj, target, tok);
384 /* does the current dir contain an item named after tok ? */
385 ko = kset_find_obj(dir, tok);
387 /* drop reference added by kset_find_obj */
390 /* ko MUST be a kset - we're about to use it as one ! */
391 if (ko->ktype != dir->kobj.ktype) {
396 /* descend into already existing subdirectory */
399 /* create new subdirectory kset */
400 subdir = kzalloc(sizeof(struct kset), GFP_KERNEL);
405 subdir->kobj.kset = dir;
406 subdir->kobj.ktype = dir->kobj.ktype;
407 ret = kobject_set_name(&subdir->kobj, "%s", tok);
412 ret = kset_register(subdir);
418 /* descend into newly created subdirectory */
423 /* we're done with cloned copy of name */
428 /* recursively unregister fw_cfg/by_name/ kset directory tree */
429 static void fw_cfg_kset_unregister_recursive(struct kset *kset)
431 struct kobject *k, *next;
433 list_for_each_entry_safe(k, next, &kset->list, entry)
434 /* all set members are ksets too, but check just in case... */
435 if (k->ktype == kset->kobj.ktype)
436 fw_cfg_kset_unregister_recursive(to_kset(k));
438 /* symlinks are cleanly and automatically removed with the directory */
439 kset_unregister(kset);
442 /* kobjects & kset representing top-level, by_key, and by_name folders */
443 static struct kobject *fw_cfg_top_ko;
444 static struct kobject *fw_cfg_sel_ko;
445 static struct kset *fw_cfg_fname_kset;
447 /* register an individual fw_cfg file */
448 static int fw_cfg_register_file(const struct fw_cfg_file *f)
451 struct fw_cfg_sysfs_entry *entry;
453 /* allocate new entry */
454 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
458 /* set file entry information */
459 memcpy(&entry->f, f, sizeof(struct fw_cfg_file));
461 /* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */
462 err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype,
463 fw_cfg_sel_ko, "%d", entry->f.select);
467 /* add raw binary content access */
468 err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw);
472 /* try adding "/sys/firmware/qemu_fw_cfg/by_name/" symlink */
473 fw_cfg_build_symlink(fw_cfg_fname_kset, &entry->kobj, entry->f.name);
475 /* success, add entry to global cache */
476 fw_cfg_sysfs_cache_enlist(entry);
480 kobject_del(&entry->kobj);
482 kobject_put(&entry->kobj);
486 /* iterate over all fw_cfg directory entries, registering each one */
487 static int fw_cfg_register_dir_entries(void)
491 struct fw_cfg_file *dir;
494 fw_cfg_read_blob(FW_CFG_FILE_DIR, &count, 0, sizeof(count));
495 count = be32_to_cpu(count);
496 dir_size = count * sizeof(struct fw_cfg_file);
498 dir = kmalloc(dir_size, GFP_KERNEL);
502 fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, sizeof(count), dir_size);
504 for (i = 0; i < count; i++) {
505 dir[i].size = be32_to_cpu(dir[i].size);
506 dir[i].select = be16_to_cpu(dir[i].select);
507 ret = fw_cfg_register_file(&dir[i]);
516 /* unregister top-level or by_key folder */
517 static inline void fw_cfg_kobj_cleanup(struct kobject *kobj)
523 static int fw_cfg_sysfs_probe(struct platform_device *pdev)
527 /* NOTE: If we supported multiple fw_cfg devices, we'd first create
528 * a subdirectory named after e.g. pdev->id, then hang per-device
529 * by_key (and by_name) subdirectories underneath it. However, only
530 * one fw_cfg device exist system-wide, so if one was already found
531 * earlier, we might as well stop here.
536 /* create by_key and by_name subdirs of /sys/firmware/qemu_fw_cfg/ */
538 fw_cfg_sel_ko = kobject_create_and_add("by_key", fw_cfg_top_ko);
541 fw_cfg_fname_kset = kset_create_and_add("by_name", NULL, fw_cfg_top_ko);
542 if (!fw_cfg_fname_kset)
545 /* initialize fw_cfg device i/o from platform data */
546 err = fw_cfg_do_platform_probe(pdev);
550 /* get revision number, add matching top-level attribute */
551 fw_cfg_read_blob(FW_CFG_ID, &fw_cfg_rev, 0, sizeof(fw_cfg_rev));
552 fw_cfg_rev = le32_to_cpu(fw_cfg_rev);
553 err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
557 /* process fw_cfg file directory entry, registering each file */
558 err = fw_cfg_register_dir_entries();
563 pr_debug("fw_cfg: loaded.\n");
567 fw_cfg_sysfs_cache_cleanup();
568 sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
572 fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset);
574 fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
579 static int fw_cfg_sysfs_remove(struct platform_device *pdev)
581 pr_debug("fw_cfg: unloading.\n");
582 fw_cfg_sysfs_cache_cleanup();
583 fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset);
584 fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
589 static const struct of_device_id fw_cfg_sysfs_mmio_match[] = {
590 { .compatible = "qemu,fw-cfg-mmio", },
593 MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match);
596 static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = {
600 MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match);
603 static struct platform_driver fw_cfg_sysfs_driver = {
604 .probe = fw_cfg_sysfs_probe,
605 .remove = fw_cfg_sysfs_remove,
608 .of_match_table = fw_cfg_sysfs_mmio_match,
609 .acpi_match_table = ACPI_PTR(fw_cfg_sysfs_acpi_match),
613 #ifdef CONFIG_FW_CFG_SYSFS_CMDLINE
615 static struct platform_device *fw_cfg_cmdline_dev;
617 /* this probably belongs in e.g. include/linux/types.h,
618 * but right now we are the only ones doing it...
620 #ifdef CONFIG_PHYS_ADDR_T_64BIT
621 #define __PHYS_ADDR_PREFIX "ll"
623 #define __PHYS_ADDR_PREFIX ""
626 /* use special scanf/printf modifier for phys_addr_t, resource_size_t */
627 #define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \
628 ":%" __PHYS_ADDR_PREFIX "i" \
629 ":%" __PHYS_ADDR_PREFIX "i%n"
631 #define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \
632 "0x%" __PHYS_ADDR_PREFIX "x"
634 #define PH_ADDR_PR_3_FMT PH_ADDR_PR_1_FMT \
635 ":%" __PHYS_ADDR_PREFIX "u" \
636 ":%" __PHYS_ADDR_PREFIX "u"
638 static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
640 struct resource res[3] = {};
643 resource_size_t size, ctrl_off, data_off;
644 int processed, consumed = 0;
646 /* only one fw_cfg device can exist system-wide, so if one
647 * was processed on the command line already, we might as
650 if (fw_cfg_cmdline_dev) {
651 /* avoid leaking previously registered device */
652 platform_device_unregister(fw_cfg_cmdline_dev);
656 /* consume "<size>" portion of command line argument */
657 size = memparse(arg, &str);
659 /* get "@<base>[:<ctrl_off>:<data_off>]" chunks */
660 processed = sscanf(str, PH_ADDR_SCAN_FMT,
662 &ctrl_off, &data_off, &consumed);
664 /* sscanf() must process precisely 1 or 3 chunks:
665 * <base> is mandatory, optionally followed by <ctrl_off>
667 * there must be no extra characters after the last chunk,
668 * so str[consumed] must be '\0'.
671 (processed != 1 && processed != 3))
675 res[0].end = base + size - 1;
676 res[0].flags = !strcmp(kp->name, "mmio") ? IORESOURCE_MEM :
679 /* insert register offsets, if provided */
681 res[1].name = "ctrl";
682 res[1].start = ctrl_off;
683 res[1].flags = IORESOURCE_REG;
684 res[2].name = "data";
685 res[2].start = data_off;
686 res[2].flags = IORESOURCE_REG;
689 /* "processed" happens to nicely match the number of resources
690 * we need to pass in to this platform device.
692 fw_cfg_cmdline_dev = platform_device_register_simple("fw_cfg",
693 PLATFORM_DEVID_NONE, res, processed);
694 if (IS_ERR(fw_cfg_cmdline_dev))
695 return PTR_ERR(fw_cfg_cmdline_dev);
700 static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp)
702 /* stay silent if device was not configured via the command
703 * line, or if the parameter name (ioport/mmio) doesn't match
706 if (!fw_cfg_cmdline_dev ||
707 (!strcmp(kp->name, "mmio") ^
708 (fw_cfg_cmdline_dev->resource[0].flags == IORESOURCE_MEM)))
711 switch (fw_cfg_cmdline_dev->num_resources) {
713 return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_1_FMT,
714 resource_size(&fw_cfg_cmdline_dev->resource[0]),
715 fw_cfg_cmdline_dev->resource[0].start);
717 return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_3_FMT,
718 resource_size(&fw_cfg_cmdline_dev->resource[0]),
719 fw_cfg_cmdline_dev->resource[0].start,
720 fw_cfg_cmdline_dev->resource[1].start,
721 fw_cfg_cmdline_dev->resource[2].start);
724 /* Should never get here */
725 WARN(1, "Unexpected number of resources: %d\n",
726 fw_cfg_cmdline_dev->num_resources);
730 static const struct kernel_param_ops fw_cfg_cmdline_param_ops = {
731 .set = fw_cfg_cmdline_set,
732 .get = fw_cfg_cmdline_get,
735 device_param_cb(ioport, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
736 device_param_cb(mmio, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
738 #endif /* CONFIG_FW_CFG_SYSFS_CMDLINE */
740 static int __init fw_cfg_sysfs_init(void)
744 /* create /sys/firmware/qemu_fw_cfg/ top level directory */
745 fw_cfg_top_ko = kobject_create_and_add("qemu_fw_cfg", firmware_kobj);
749 ret = platform_driver_register(&fw_cfg_sysfs_driver);
751 fw_cfg_kobj_cleanup(fw_cfg_top_ko);
756 static void __exit fw_cfg_sysfs_exit(void)
758 platform_driver_unregister(&fw_cfg_sysfs_driver);
760 #ifdef CONFIG_FW_CFG_SYSFS_CMDLINE
761 platform_device_unregister(fw_cfg_cmdline_dev);
764 /* clean up /sys/firmware/qemu_fw_cfg/ */
765 fw_cfg_kobj_cleanup(fw_cfg_top_ko);
768 module_init(fw_cfg_sysfs_init);
769 module_exit(fw_cfg_sysfs_exit);