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 # warning "QEMU FW_CFG may not be available on this architecture!"
129 # define FW_CFG_CTRL_OFF 0x00
130 # define FW_CFG_DATA_OFF 0x01
134 /* initialize fw_cfg device i/o from platform data */
135 static int fw_cfg_do_platform_probe(struct platform_device *pdev)
137 char sig[FW_CFG_SIG_SIZE];
138 struct resource *range, *ctrl, *data;
140 /* acquire i/o range details */
141 fw_cfg_is_mmio = false;
142 range = platform_get_resource(pdev, IORESOURCE_IO, 0);
144 fw_cfg_is_mmio = true;
145 range = platform_get_resource(pdev, IORESOURCE_MEM, 0);
149 fw_cfg_p_base = range->start;
150 fw_cfg_p_size = resource_size(range);
152 if (fw_cfg_is_mmio) {
153 if (!request_mem_region(fw_cfg_p_base,
154 fw_cfg_p_size, "fw_cfg_mem"))
156 fw_cfg_dev_base = ioremap(fw_cfg_p_base, fw_cfg_p_size);
157 if (!fw_cfg_dev_base) {
158 release_mem_region(fw_cfg_p_base, fw_cfg_p_size);
162 if (!request_region(fw_cfg_p_base,
163 fw_cfg_p_size, "fw_cfg_io"))
165 fw_cfg_dev_base = ioport_map(fw_cfg_p_base, fw_cfg_p_size);
166 if (!fw_cfg_dev_base) {
167 release_region(fw_cfg_p_base, fw_cfg_p_size);
172 /* were custom register offsets provided (e.g. on the command line)? */
173 ctrl = platform_get_resource_byname(pdev, IORESOURCE_REG, "ctrl");
174 data = platform_get_resource_byname(pdev, IORESOURCE_REG, "data");
176 fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start;
177 fw_cfg_reg_data = fw_cfg_dev_base + data->start;
179 /* use architecture-specific offsets */
180 fw_cfg_reg_ctrl = fw_cfg_dev_base + FW_CFG_CTRL_OFF;
181 fw_cfg_reg_data = fw_cfg_dev_base + FW_CFG_DATA_OFF;
184 /* verify fw_cfg device signature */
185 fw_cfg_read_blob(FW_CFG_SIGNATURE, sig, 0, FW_CFG_SIG_SIZE);
186 if (memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) {
194 /* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */
195 static u32 fw_cfg_rev;
197 static ssize_t fw_cfg_showrev(struct kobject *k, struct attribute *a, char *buf)
199 return sprintf(buf, "%u\n", fw_cfg_rev);
202 static const struct {
203 struct attribute attr;
204 ssize_t (*show)(struct kobject *k, struct attribute *a, char *buf);
205 } fw_cfg_rev_attr = {
206 .attr = { .name = "rev", .mode = S_IRUSR },
207 .show = fw_cfg_showrev,
210 /* fw_cfg_sysfs_entry type */
211 struct fw_cfg_sysfs_entry {
213 struct fw_cfg_file f;
214 struct list_head list;
217 /* get fw_cfg_sysfs_entry from kobject member */
218 static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj)
220 return container_of(kobj, struct fw_cfg_sysfs_entry, kobj);
223 /* fw_cfg_sysfs_attribute type */
224 struct fw_cfg_sysfs_attribute {
225 struct attribute attr;
226 ssize_t (*show)(struct fw_cfg_sysfs_entry *entry, char *buf);
229 /* get fw_cfg_sysfs_attribute from attribute member */
230 static inline struct fw_cfg_sysfs_attribute *to_attr(struct attribute *attr)
232 return container_of(attr, struct fw_cfg_sysfs_attribute, attr);
235 /* global cache of fw_cfg_sysfs_entry objects */
236 static LIST_HEAD(fw_cfg_entry_cache);
238 /* kobjects removed lazily by kernel, mutual exclusion needed */
239 static DEFINE_SPINLOCK(fw_cfg_cache_lock);
241 static inline void fw_cfg_sysfs_cache_enlist(struct fw_cfg_sysfs_entry *entry)
243 spin_lock(&fw_cfg_cache_lock);
244 list_add_tail(&entry->list, &fw_cfg_entry_cache);
245 spin_unlock(&fw_cfg_cache_lock);
248 static inline void fw_cfg_sysfs_cache_delist(struct fw_cfg_sysfs_entry *entry)
250 spin_lock(&fw_cfg_cache_lock);
251 list_del(&entry->list);
252 spin_unlock(&fw_cfg_cache_lock);
255 static void fw_cfg_sysfs_cache_cleanup(void)
257 struct fw_cfg_sysfs_entry *entry, *next;
259 list_for_each_entry_safe(entry, next, &fw_cfg_entry_cache, list) {
260 /* will end up invoking fw_cfg_sysfs_cache_delist()
261 * via each object's release() method (i.e. destructor)
263 kobject_put(&entry->kobj);
267 /* default_attrs: per-entry attributes and show methods */
269 #define FW_CFG_SYSFS_ATTR(_attr) \
270 struct fw_cfg_sysfs_attribute fw_cfg_sysfs_attr_##_attr = { \
271 .attr = { .name = __stringify(_attr), .mode = S_IRUSR }, \
272 .show = fw_cfg_sysfs_show_##_attr, \
275 static ssize_t fw_cfg_sysfs_show_size(struct fw_cfg_sysfs_entry *e, char *buf)
277 return sprintf(buf, "%u\n", e->f.size);
280 static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf)
282 return sprintf(buf, "%u\n", e->f.select);
285 static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf)
287 return sprintf(buf, "%s\n", e->f.name);
290 static FW_CFG_SYSFS_ATTR(size);
291 static FW_CFG_SYSFS_ATTR(key);
292 static FW_CFG_SYSFS_ATTR(name);
294 static struct attribute *fw_cfg_sysfs_entry_attrs[] = {
295 &fw_cfg_sysfs_attr_size.attr,
296 &fw_cfg_sysfs_attr_key.attr,
297 &fw_cfg_sysfs_attr_name.attr,
301 /* sysfs_ops: find fw_cfg_[entry, attribute] and call appropriate show method */
302 static ssize_t fw_cfg_sysfs_attr_show(struct kobject *kobj, struct attribute *a,
305 struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
306 struct fw_cfg_sysfs_attribute *attr = to_attr(a);
308 return attr->show(entry, buf);
311 static const struct sysfs_ops fw_cfg_sysfs_attr_ops = {
312 .show = fw_cfg_sysfs_attr_show,
315 /* release: destructor, to be called via kobject_put() */
316 static void fw_cfg_sysfs_release_entry(struct kobject *kobj)
318 struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
320 fw_cfg_sysfs_cache_delist(entry);
324 /* kobj_type: ties together all properties required to register an entry */
325 static struct kobj_type fw_cfg_sysfs_entry_ktype = {
326 .default_attrs = fw_cfg_sysfs_entry_attrs,
327 .sysfs_ops = &fw_cfg_sysfs_attr_ops,
328 .release = fw_cfg_sysfs_release_entry,
331 /* raw-read method and attribute */
332 static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
333 struct bin_attribute *bin_attr,
334 char *buf, loff_t pos, size_t count)
336 struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
338 if (pos > entry->f.size)
341 if (count > entry->f.size - pos)
342 count = entry->f.size - pos;
344 fw_cfg_read_blob(entry->f.select, buf, pos, count);
348 static struct bin_attribute fw_cfg_sysfs_attr_raw = {
349 .attr = { .name = "raw", .mode = S_IRUSR },
350 .read = fw_cfg_sysfs_read_raw,
354 * Create a kset subdirectory matching each '/' delimited dirname token
355 * in 'name', starting with sysfs kset/folder 'dir'; At the end, create
356 * a symlink directed at the given 'target'.
357 * NOTE: We do this on a best-effort basis, since 'name' is not guaranteed
358 * to be a well-behaved path name. Whenever a symlink vs. kset directory
359 * name collision occurs, the kernel will issue big scary warnings while
360 * refusing to add the offending link or directory. We follow up with our
361 * own, slightly less scary error messages explaining the situation :)
363 static int fw_cfg_build_symlink(struct kset *dir,
364 struct kobject *target, const char *name)
369 char *name_copy, *p, *tok;
371 if (!dir || !target || !name || !*name)
374 /* clone a copy of name for parsing */
375 name_copy = p = kstrdup(name, GFP_KERNEL);
379 /* create folders for each dirname token, then symlink for basename */
380 while ((tok = strsep(&p, "/")) && *tok) {
382 /* last (basename) token? If so, add symlink here */
384 ret = sysfs_create_link(&dir->kobj, target, tok);
388 /* does the current dir contain an item named after tok ? */
389 ko = kset_find_obj(dir, tok);
391 /* drop reference added by kset_find_obj */
394 /* ko MUST be a kset - we're about to use it as one ! */
395 if (ko->ktype != dir->kobj.ktype) {
400 /* descend into already existing subdirectory */
403 /* create new subdirectory kset */
404 subdir = kzalloc(sizeof(struct kset), GFP_KERNEL);
409 subdir->kobj.kset = dir;
410 subdir->kobj.ktype = dir->kobj.ktype;
411 ret = kobject_set_name(&subdir->kobj, "%s", tok);
416 ret = kset_register(subdir);
422 /* descend into newly created subdirectory */
427 /* we're done with cloned copy of name */
432 /* recursively unregister fw_cfg/by_name/ kset directory tree */
433 static void fw_cfg_kset_unregister_recursive(struct kset *kset)
435 struct kobject *k, *next;
437 list_for_each_entry_safe(k, next, &kset->list, entry)
438 /* all set members are ksets too, but check just in case... */
439 if (k->ktype == kset->kobj.ktype)
440 fw_cfg_kset_unregister_recursive(to_kset(k));
442 /* symlinks are cleanly and automatically removed with the directory */
443 kset_unregister(kset);
446 /* kobjects & kset representing top-level, by_key, and by_name folders */
447 static struct kobject *fw_cfg_top_ko;
448 static struct kobject *fw_cfg_sel_ko;
449 static struct kset *fw_cfg_fname_kset;
451 /* register an individual fw_cfg file */
452 static int fw_cfg_register_file(const struct fw_cfg_file *f)
455 struct fw_cfg_sysfs_entry *entry;
457 /* allocate new entry */
458 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
462 /* set file entry information */
463 memcpy(&entry->f, f, sizeof(struct fw_cfg_file));
465 /* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */
466 err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype,
467 fw_cfg_sel_ko, "%d", entry->f.select);
471 /* add raw binary content access */
472 err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw);
476 /* try adding "/sys/firmware/qemu_fw_cfg/by_name/" symlink */
477 fw_cfg_build_symlink(fw_cfg_fname_kset, &entry->kobj, entry->f.name);
479 /* success, add entry to global cache */
480 fw_cfg_sysfs_cache_enlist(entry);
484 kobject_del(&entry->kobj);
490 /* iterate over all fw_cfg directory entries, registering each one */
491 static int fw_cfg_register_dir_entries(void)
495 struct fw_cfg_file *dir;
498 fw_cfg_read_blob(FW_CFG_FILE_DIR, &count, 0, sizeof(count));
499 count = be32_to_cpu(count);
500 dir_size = count * sizeof(struct fw_cfg_file);
502 dir = kmalloc(dir_size, GFP_KERNEL);
506 fw_cfg_read_blob(FW_CFG_FILE_DIR, dir, sizeof(count), dir_size);
508 for (i = 0; i < count; i++) {
509 dir[i].size = be32_to_cpu(dir[i].size);
510 dir[i].select = be16_to_cpu(dir[i].select);
511 ret = fw_cfg_register_file(&dir[i]);
520 /* unregister top-level or by_key folder */
521 static inline void fw_cfg_kobj_cleanup(struct kobject *kobj)
527 static int fw_cfg_sysfs_probe(struct platform_device *pdev)
531 /* NOTE: If we supported multiple fw_cfg devices, we'd first create
532 * a subdirectory named after e.g. pdev->id, then hang per-device
533 * by_key (and by_name) subdirectories underneath it. However, only
534 * one fw_cfg device exist system-wide, so if one was already found
535 * earlier, we might as well stop here.
540 /* create by_key and by_name subdirs of /sys/firmware/qemu_fw_cfg/ */
542 fw_cfg_sel_ko = kobject_create_and_add("by_key", fw_cfg_top_ko);
545 fw_cfg_fname_kset = kset_create_and_add("by_name", NULL, fw_cfg_top_ko);
546 if (!fw_cfg_fname_kset)
549 /* initialize fw_cfg device i/o from platform data */
550 err = fw_cfg_do_platform_probe(pdev);
554 /* get revision number, add matching top-level attribute */
555 fw_cfg_read_blob(FW_CFG_ID, &fw_cfg_rev, 0, sizeof(fw_cfg_rev));
556 fw_cfg_rev = le32_to_cpu(fw_cfg_rev);
557 err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
561 /* process fw_cfg file directory entry, registering each file */
562 err = fw_cfg_register_dir_entries();
567 pr_debug("fw_cfg: loaded.\n");
571 fw_cfg_sysfs_cache_cleanup();
572 sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
576 fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset);
578 fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
583 static int fw_cfg_sysfs_remove(struct platform_device *pdev)
585 pr_debug("fw_cfg: unloading.\n");
586 fw_cfg_sysfs_cache_cleanup();
587 fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset);
588 fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
593 static const struct of_device_id fw_cfg_sysfs_mmio_match[] = {
594 { .compatible = "qemu,fw-cfg-mmio", },
597 MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match);
600 static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = {
604 MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match);
607 static struct platform_driver fw_cfg_sysfs_driver = {
608 .probe = fw_cfg_sysfs_probe,
609 .remove = fw_cfg_sysfs_remove,
612 .of_match_table = fw_cfg_sysfs_mmio_match,
613 .acpi_match_table = ACPI_PTR(fw_cfg_sysfs_acpi_match),
617 #ifdef CONFIG_FW_CFG_SYSFS_CMDLINE
619 static struct platform_device *fw_cfg_cmdline_dev;
621 /* this probably belongs in e.g. include/linux/types.h,
622 * but right now we are the only ones doing it...
624 #ifdef CONFIG_PHYS_ADDR_T_64BIT
625 #define __PHYS_ADDR_PREFIX "ll"
627 #define __PHYS_ADDR_PREFIX ""
630 /* use special scanf/printf modifier for phys_addr_t, resource_size_t */
631 #define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \
632 ":%" __PHYS_ADDR_PREFIX "i" \
633 ":%" __PHYS_ADDR_PREFIX "i%n"
635 #define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \
636 "0x%" __PHYS_ADDR_PREFIX "x"
638 #define PH_ADDR_PR_3_FMT PH_ADDR_PR_1_FMT \
639 ":%" __PHYS_ADDR_PREFIX "u" \
640 ":%" __PHYS_ADDR_PREFIX "u"
642 static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
644 struct resource res[3] = {};
647 resource_size_t size, ctrl_off, data_off;
648 int processed, consumed = 0;
650 /* only one fw_cfg device can exist system-wide, so if one
651 * was processed on the command line already, we might as
654 if (fw_cfg_cmdline_dev) {
655 /* avoid leaking previously registered device */
656 platform_device_unregister(fw_cfg_cmdline_dev);
660 /* consume "<size>" portion of command line argument */
661 size = memparse(arg, &str);
663 /* get "@<base>[:<ctrl_off>:<data_off>]" chunks */
664 processed = sscanf(str, PH_ADDR_SCAN_FMT,
666 &ctrl_off, &data_off, &consumed);
668 /* sscanf() must process precisely 1 or 3 chunks:
669 * <base> is mandatory, optionally followed by <ctrl_off>
671 * there must be no extra characters after the last chunk,
672 * so str[consumed] must be '\0'.
675 (processed != 1 && processed != 3))
679 res[0].end = base + size - 1;
680 res[0].flags = !strcmp(kp->name, "mmio") ? IORESOURCE_MEM :
683 /* insert register offsets, if provided */
685 res[1].name = "ctrl";
686 res[1].start = ctrl_off;
687 res[1].flags = IORESOURCE_REG;
688 res[2].name = "data";
689 res[2].start = data_off;
690 res[2].flags = IORESOURCE_REG;
693 /* "processed" happens to nicely match the number of resources
694 * we need to pass in to this platform device.
696 fw_cfg_cmdline_dev = platform_device_register_simple("fw_cfg",
697 PLATFORM_DEVID_NONE, res, processed);
698 if (IS_ERR(fw_cfg_cmdline_dev))
699 return PTR_ERR(fw_cfg_cmdline_dev);
704 static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp)
706 /* stay silent if device was not configured via the command
707 * line, or if the parameter name (ioport/mmio) doesn't match
710 if (!fw_cfg_cmdline_dev ||
711 (!strcmp(kp->name, "mmio") ^
712 (fw_cfg_cmdline_dev->resource[0].flags == IORESOURCE_MEM)))
715 switch (fw_cfg_cmdline_dev->num_resources) {
717 return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_1_FMT,
718 resource_size(&fw_cfg_cmdline_dev->resource[0]),
719 fw_cfg_cmdline_dev->resource[0].start);
721 return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_3_FMT,
722 resource_size(&fw_cfg_cmdline_dev->resource[0]),
723 fw_cfg_cmdline_dev->resource[0].start,
724 fw_cfg_cmdline_dev->resource[1].start,
725 fw_cfg_cmdline_dev->resource[2].start);
728 /* Should never get here */
729 WARN(1, "Unexpected number of resources: %d\n",
730 fw_cfg_cmdline_dev->num_resources);
734 static const struct kernel_param_ops fw_cfg_cmdline_param_ops = {
735 .set = fw_cfg_cmdline_set,
736 .get = fw_cfg_cmdline_get,
739 device_param_cb(ioport, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
740 device_param_cb(mmio, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
742 #endif /* CONFIG_FW_CFG_SYSFS_CMDLINE */
744 static int __init fw_cfg_sysfs_init(void)
748 /* create /sys/firmware/qemu_fw_cfg/ top level directory */
749 fw_cfg_top_ko = kobject_create_and_add("qemu_fw_cfg", firmware_kobj);
753 ret = platform_driver_register(&fw_cfg_sysfs_driver);
755 fw_cfg_kobj_cleanup(fw_cfg_top_ko);
760 static void __exit fw_cfg_sysfs_exit(void)
762 platform_driver_unregister(&fw_cfg_sysfs_driver);
764 #ifdef CONFIG_FW_CFG_SYSFS_CMDLINE
765 platform_device_unregister(fw_cfg_cmdline_dev);
768 /* clean up /sys/firmware/qemu_fw_cfg/ */
769 fw_cfg_kobj_cleanup(fw_cfg_top_ko);
772 module_init(fw_cfg_sysfs_init);
773 module_exit(fw_cfg_sysfs_exit);