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 *      [qemu_fw_cfg.]ioport=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]
 14 * or
 15 *      [qemu_fw_cfg.]mmio=<size>@<base>[:<ctrl_off>:<data_off>[:<dma_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 *      <dma_off> := (optional) offset of dma register
 23 *
 24 * e.g.:
 25 *      qemu_fw_cfg.ioport=12@0x510:0:1:4	(the default on x86)
 26 * or
 27 *      qemu_fw_cfg.mmio=16@0x9020000:8:0:16	(the default on arm)
 28 */
 29
 30#include <linux/module.h>
 31#include <linux/mod_devicetable.h>
 32#include <linux/platform_device.h>
 33#include <linux/acpi.h>
 34#include <linux/slab.h>
 35#include <linux/io.h>
 36#include <linux/ioport.h>
 37#include <uapi/linux/qemu_fw_cfg.h>
 38#include <linux/delay.h>
 39#include <linux/crash_dump.h>
 40#include <linux/crash_core.h>
 41
 42MODULE_AUTHOR("Gabriel L. Somlo <somlo@cmu.edu>");
 43MODULE_DESCRIPTION("QEMU fw_cfg sysfs support");
 44MODULE_LICENSE("GPL");
 45
 46/* fw_cfg revision attribute, in /sys/firmware/qemu_fw_cfg top-level dir. */
 47static u32 fw_cfg_rev;
 48
 49/* fw_cfg device i/o register addresses */
 50static bool fw_cfg_is_mmio;
 51static phys_addr_t fw_cfg_p_base;
 52static resource_size_t fw_cfg_p_size;
 53static void __iomem *fw_cfg_dev_base;
 54static void __iomem *fw_cfg_reg_ctrl;
 55static void __iomem *fw_cfg_reg_data;
 56static void __iomem *fw_cfg_reg_dma;
 57
 58/* atomic access to fw_cfg device (potentially slow i/o, so using mutex) */
 59static DEFINE_MUTEX(fw_cfg_dev_lock);
 60
 61/* pick appropriate endianness for selector key */
 62static void fw_cfg_sel_endianness(u16 key)
 63{
 64	if (fw_cfg_is_mmio)
 65		iowrite16be(key, fw_cfg_reg_ctrl);
 66	else
 67		iowrite16(key, fw_cfg_reg_ctrl);
 68}
 69
 70#ifdef CONFIG_CRASH_CORE
 71static inline bool fw_cfg_dma_enabled(void)
 72{
 73	return (fw_cfg_rev & FW_CFG_VERSION_DMA) && fw_cfg_reg_dma;
 74}
 75
 76/* qemu fw_cfg device is sync today, but spec says it may become async */
 77static void fw_cfg_wait_for_control(struct fw_cfg_dma_access *d)
 78{
 79	for (;;) {
 80		u32 ctrl = be32_to_cpu(READ_ONCE(d->control));
 81
 82		/* do not reorder the read to d->control */
 83		rmb();
 84		if ((ctrl & ~FW_CFG_DMA_CTL_ERROR) == 0)
 85			return;
 86
 87		cpu_relax();
 88	}
 89}
 90
 91static ssize_t fw_cfg_dma_transfer(void *address, u32 length, u32 control)
 92{
 93	phys_addr_t dma;
 94	struct fw_cfg_dma_access *d = NULL;
 95	ssize_t ret = length;
 96
 97	d = kmalloc(sizeof(*d), GFP_KERNEL);
 98	if (!d) {
 99		ret = -ENOMEM;
100		goto end;
101	}
102
103	/* fw_cfg device does not need IOMMU protection, so use physical addresses */
104	*d = (struct fw_cfg_dma_access) {
105		.address = cpu_to_be64(address ? virt_to_phys(address) : 0),
106		.length = cpu_to_be32(length),
107		.control = cpu_to_be32(control)
108	};
109
110	dma = virt_to_phys(d);
111
112	iowrite32be((u64)dma >> 32, fw_cfg_reg_dma);
113	/* force memory to sync before notifying device via MMIO */
114	wmb();
115	iowrite32be(dma, fw_cfg_reg_dma + 4);
116
117	fw_cfg_wait_for_control(d);
118
119	if (be32_to_cpu(READ_ONCE(d->control)) & FW_CFG_DMA_CTL_ERROR) {
120		ret = -EIO;
121	}
122
123end:
124	kfree(d);
125
126	return ret;
127}
128#endif
129
130/* read chunk of given fw_cfg blob (caller responsible for sanity-check) */
131static ssize_t fw_cfg_read_blob(u16 key,
132				void *buf, loff_t pos, size_t count)
133{
134	u32 glk = -1U;
135	acpi_status status;
136
137	/* If we have ACPI, ensure mutual exclusion against any potential
138	 * device access by the firmware, e.g. via AML methods:
139	 */
140	status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
141	if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
142		/* Should never get here */
143		WARN(1, "fw_cfg_read_blob: Failed to lock ACPI!\n");
144		memset(buf, 0, count);
145		return -EINVAL;
146	}
147
148	mutex_lock(&fw_cfg_dev_lock);
149	fw_cfg_sel_endianness(key);
150	while (pos-- > 0)
151		ioread8(fw_cfg_reg_data);
152	ioread8_rep(fw_cfg_reg_data, buf, count);
153	mutex_unlock(&fw_cfg_dev_lock);
154
155	acpi_release_global_lock(glk);
156	return count;
157}
158
159#ifdef CONFIG_CRASH_CORE
160/* write chunk of given fw_cfg blob (caller responsible for sanity-check) */
161static ssize_t fw_cfg_write_blob(u16 key,
162				 void *buf, loff_t pos, size_t count)
163{
164	u32 glk = -1U;
165	acpi_status status;
166	ssize_t ret = count;
167
168	/* If we have ACPI, ensure mutual exclusion against any potential
169	 * device access by the firmware, e.g. via AML methods:
170	 */
171	status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk);
172	if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) {
173		/* Should never get here */
174		WARN(1, "%s: Failed to lock ACPI!\n", __func__);
175		return -EINVAL;
176	}
177
178	mutex_lock(&fw_cfg_dev_lock);
179	if (pos == 0) {
180		ret = fw_cfg_dma_transfer(buf, count, key << 16
181					  | FW_CFG_DMA_CTL_SELECT
182					  | FW_CFG_DMA_CTL_WRITE);
183	} else {
184		fw_cfg_sel_endianness(key);
185		ret = fw_cfg_dma_transfer(NULL, pos, FW_CFG_DMA_CTL_SKIP);
186		if (ret < 0)
187			goto end;
188		ret = fw_cfg_dma_transfer(buf, count, FW_CFG_DMA_CTL_WRITE);
189	}
190
191end:
192	mutex_unlock(&fw_cfg_dev_lock);
193
194	acpi_release_global_lock(glk);
195
196	return ret;
197}
198#endif /* CONFIG_CRASH_CORE */
199
200/* clean up fw_cfg device i/o */
201static void fw_cfg_io_cleanup(void)
202{
203	if (fw_cfg_is_mmio) {
204		iounmap(fw_cfg_dev_base);
205		release_mem_region(fw_cfg_p_base, fw_cfg_p_size);
206	} else {
207		ioport_unmap(fw_cfg_dev_base);
208		release_region(fw_cfg_p_base, fw_cfg_p_size);
209	}
210}
211
212/* arch-specific ctrl & data register offsets are not available in ACPI, DT */
213#if !(defined(FW_CFG_CTRL_OFF) && defined(FW_CFG_DATA_OFF))
214# if (defined(CONFIG_ARM) || defined(CONFIG_ARM64) || defined(CONFIG_RISCV))
215#  define FW_CFG_CTRL_OFF 0x08
216#  define FW_CFG_DATA_OFF 0x00
217#  define FW_CFG_DMA_OFF 0x10
218# elif defined(CONFIG_PARISC)	/* parisc */
219#  define FW_CFG_CTRL_OFF 0x00
220#  define FW_CFG_DATA_OFF 0x04
221# elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */
222#  define FW_CFG_CTRL_OFF 0x00
223#  define FW_CFG_DATA_OFF 0x02
224# elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */
225#  define FW_CFG_CTRL_OFF 0x00
226#  define FW_CFG_DATA_OFF 0x01
227#  define FW_CFG_DMA_OFF 0x04
228# else
229#  error "QEMU FW_CFG not available on this architecture!"
230# endif
231#endif
232
233/* initialize fw_cfg device i/o from platform data */
234static int fw_cfg_do_platform_probe(struct platform_device *pdev)
235{
236	char sig[FW_CFG_SIG_SIZE];
237	struct resource *range, *ctrl, *data, *dma;
238
239	/* acquire i/o range details */
240	fw_cfg_is_mmio = false;
241	range = platform_get_resource(pdev, IORESOURCE_IO, 0);
242	if (!range) {
243		fw_cfg_is_mmio = true;
244		range = platform_get_resource(pdev, IORESOURCE_MEM, 0);
245		if (!range)
246			return -EINVAL;
247	}
248	fw_cfg_p_base = range->start;
249	fw_cfg_p_size = resource_size(range);
250
251	if (fw_cfg_is_mmio) {
252		if (!request_mem_region(fw_cfg_p_base,
253					fw_cfg_p_size, "fw_cfg_mem"))
254			return -EBUSY;
255		fw_cfg_dev_base = ioremap(fw_cfg_p_base, fw_cfg_p_size);
256		if (!fw_cfg_dev_base) {
257			release_mem_region(fw_cfg_p_base, fw_cfg_p_size);
258			return -EFAULT;
259		}
260	} else {
261		if (!request_region(fw_cfg_p_base,
262				    fw_cfg_p_size, "fw_cfg_io"))
263			return -EBUSY;
264		fw_cfg_dev_base = ioport_map(fw_cfg_p_base, fw_cfg_p_size);
265		if (!fw_cfg_dev_base) {
266			release_region(fw_cfg_p_base, fw_cfg_p_size);
267			return -EFAULT;
268		}
269	}
270
271	/* were custom register offsets provided (e.g. on the command line)? */
272	ctrl = platform_get_resource_byname(pdev, IORESOURCE_REG, "ctrl");
273	data = platform_get_resource_byname(pdev, IORESOURCE_REG, "data");
274	dma = platform_get_resource_byname(pdev, IORESOURCE_REG, "dma");
275	if (ctrl && data) {
276		fw_cfg_reg_ctrl = fw_cfg_dev_base + ctrl->start;
277		fw_cfg_reg_data = fw_cfg_dev_base + data->start;
278	} else {
279		/* use architecture-specific offsets */
280		fw_cfg_reg_ctrl = fw_cfg_dev_base + FW_CFG_CTRL_OFF;
281		fw_cfg_reg_data = fw_cfg_dev_base + FW_CFG_DATA_OFF;
282	}
283
284	if (dma)
285		fw_cfg_reg_dma = fw_cfg_dev_base + dma->start;
286#ifdef FW_CFG_DMA_OFF
287	else
288		fw_cfg_reg_dma = fw_cfg_dev_base + FW_CFG_DMA_OFF;
289#endif
290
291	/* verify fw_cfg device signature */
292	if (fw_cfg_read_blob(FW_CFG_SIGNATURE, sig,
293				0, FW_CFG_SIG_SIZE) < 0 ||
294		memcmp(sig, "QEMU", FW_CFG_SIG_SIZE) != 0) {
295		fw_cfg_io_cleanup();
296		return -ENODEV;
297	}
298
299	return 0;
300}
301
302static ssize_t fw_cfg_showrev(struct kobject *k, struct kobj_attribute *a,
303			      char *buf)
304{
305	return sprintf(buf, "%u\n", fw_cfg_rev);
306}
307
308static const struct kobj_attribute fw_cfg_rev_attr = {
309	.attr = { .name = "rev", .mode = S_IRUSR },
310	.show = fw_cfg_showrev,
311};
312
313/* fw_cfg_sysfs_entry type */
314struct fw_cfg_sysfs_entry {
315	struct kobject kobj;
316	u32 size;
317	u16 select;
318	char name[FW_CFG_MAX_FILE_PATH];
319	struct list_head list;
320};
321
322#ifdef CONFIG_CRASH_CORE
323static ssize_t fw_cfg_write_vmcoreinfo(const struct fw_cfg_file *f)
324{
325	static struct fw_cfg_vmcoreinfo *data;
326	ssize_t ret;
327
328	data = kmalloc(sizeof(struct fw_cfg_vmcoreinfo), GFP_KERNEL);
329	if (!data)
330		return -ENOMEM;
331
332	*data = (struct fw_cfg_vmcoreinfo) {
333		.guest_format = cpu_to_le16(FW_CFG_VMCOREINFO_FORMAT_ELF),
334		.size = cpu_to_le32(VMCOREINFO_NOTE_SIZE),
335		.paddr = cpu_to_le64(paddr_vmcoreinfo_note())
336	};
337	/* spare ourself reading host format support for now since we
338	 * don't know what else to format - host may ignore ours
339	 */
340	ret = fw_cfg_write_blob(be16_to_cpu(f->select), data,
341				0, sizeof(struct fw_cfg_vmcoreinfo));
342
343	kfree(data);
344	return ret;
345}
346#endif /* CONFIG_CRASH_CORE */
347
348/* get fw_cfg_sysfs_entry from kobject member */
349static inline struct fw_cfg_sysfs_entry *to_entry(struct kobject *kobj)
350{
351	return container_of(kobj, struct fw_cfg_sysfs_entry, kobj);
352}
353
354/* fw_cfg_sysfs_attribute type */
355struct fw_cfg_sysfs_attribute {
356	struct attribute attr;
357	ssize_t (*show)(struct fw_cfg_sysfs_entry *entry, char *buf);
358};
359
360/* get fw_cfg_sysfs_attribute from attribute member */
361static inline struct fw_cfg_sysfs_attribute *to_attr(struct attribute *attr)
362{
363	return container_of(attr, struct fw_cfg_sysfs_attribute, attr);
364}
365
366/* global cache of fw_cfg_sysfs_entry objects */
367static LIST_HEAD(fw_cfg_entry_cache);
368
369/* kobjects removed lazily by kernel, mutual exclusion needed */
370static DEFINE_SPINLOCK(fw_cfg_cache_lock);
371
372static inline void fw_cfg_sysfs_cache_enlist(struct fw_cfg_sysfs_entry *entry)
373{
374	spin_lock(&fw_cfg_cache_lock);
375	list_add_tail(&entry->list, &fw_cfg_entry_cache);
376	spin_unlock(&fw_cfg_cache_lock);
377}
378
379static inline void fw_cfg_sysfs_cache_delist(struct fw_cfg_sysfs_entry *entry)
380{
381	spin_lock(&fw_cfg_cache_lock);
382	list_del(&entry->list);
383	spin_unlock(&fw_cfg_cache_lock);
384}
385
386static void fw_cfg_sysfs_cache_cleanup(void)
387{
388	struct fw_cfg_sysfs_entry *entry, *next;
389
390	list_for_each_entry_safe(entry, next, &fw_cfg_entry_cache, list) {
391		fw_cfg_sysfs_cache_delist(entry);
392		kobject_del(&entry->kobj);
 
393		kobject_put(&entry->kobj);
394	}
395}
396
397/* per-entry attributes and show methods */
398
399#define FW_CFG_SYSFS_ATTR(_attr) \
400struct fw_cfg_sysfs_attribute fw_cfg_sysfs_attr_##_attr = { \
401	.attr = { .name = __stringify(_attr), .mode = S_IRUSR }, \
402	.show = fw_cfg_sysfs_show_##_attr, \
403}
404
405static ssize_t fw_cfg_sysfs_show_size(struct fw_cfg_sysfs_entry *e, char *buf)
406{
407	return sprintf(buf, "%u\n", e->size);
408}
409
410static ssize_t fw_cfg_sysfs_show_key(struct fw_cfg_sysfs_entry *e, char *buf)
411{
412	return sprintf(buf, "%u\n", e->select);
413}
414
415static ssize_t fw_cfg_sysfs_show_name(struct fw_cfg_sysfs_entry *e, char *buf)
416{
417	return sprintf(buf, "%s\n", e->name);
418}
419
420static FW_CFG_SYSFS_ATTR(size);
421static FW_CFG_SYSFS_ATTR(key);
422static FW_CFG_SYSFS_ATTR(name);
423
424static struct attribute *fw_cfg_sysfs_entry_attrs[] = {
425	&fw_cfg_sysfs_attr_size.attr,
426	&fw_cfg_sysfs_attr_key.attr,
427	&fw_cfg_sysfs_attr_name.attr,
428	NULL,
429};
430ATTRIBUTE_GROUPS(fw_cfg_sysfs_entry);
431
432/* sysfs_ops: find fw_cfg_[entry, attribute] and call appropriate show method */
433static ssize_t fw_cfg_sysfs_attr_show(struct kobject *kobj, struct attribute *a,
434				      char *buf)
435{
436	struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
437	struct fw_cfg_sysfs_attribute *attr = to_attr(a);
438
439	return attr->show(entry, buf);
440}
441
442static const struct sysfs_ops fw_cfg_sysfs_attr_ops = {
443	.show = fw_cfg_sysfs_attr_show,
444};
445
446/* release: destructor, to be called via kobject_put() */
447static void fw_cfg_sysfs_release_entry(struct kobject *kobj)
448{
449	struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
450
 
451	kfree(entry);
452}
453
454/* kobj_type: ties together all properties required to register an entry */
455static struct kobj_type fw_cfg_sysfs_entry_ktype = {
456	.default_groups = fw_cfg_sysfs_entry_groups,
457	.sysfs_ops = &fw_cfg_sysfs_attr_ops,
458	.release = fw_cfg_sysfs_release_entry,
459};
460
461/* raw-read method and attribute */
462static ssize_t fw_cfg_sysfs_read_raw(struct file *filp, struct kobject *kobj,
463				     struct bin_attribute *bin_attr,
464				     char *buf, loff_t pos, size_t count)
465{
466	struct fw_cfg_sysfs_entry *entry = to_entry(kobj);
467
468	if (pos > entry->size)
469		return -EINVAL;
470
471	if (count > entry->size - pos)
472		count = entry->size - pos;
473
474	return fw_cfg_read_blob(entry->select, buf, pos, count);
475}
476
477static struct bin_attribute fw_cfg_sysfs_attr_raw = {
478	.attr = { .name = "raw", .mode = S_IRUSR },
479	.read = fw_cfg_sysfs_read_raw,
480};
481
482/*
483 * Create a kset subdirectory matching each '/' delimited dirname token
484 * in 'name', starting with sysfs kset/folder 'dir'; At the end, create
485 * a symlink directed at the given 'target'.
486 * NOTE: We do this on a best-effort basis, since 'name' is not guaranteed
487 * to be a well-behaved path name. Whenever a symlink vs. kset directory
488 * name collision occurs, the kernel will issue big scary warnings while
489 * refusing to add the offending link or directory. We follow up with our
490 * own, slightly less scary error messages explaining the situation :)
491 */
492static int fw_cfg_build_symlink(struct kset *dir,
493				struct kobject *target, const char *name)
494{
495	int ret;
496	struct kset *subdir;
497	struct kobject *ko;
498	char *name_copy, *p, *tok;
499
500	if (!dir || !target || !name || !*name)
501		return -EINVAL;
502
503	/* clone a copy of name for parsing */
504	name_copy = p = kstrdup(name, GFP_KERNEL);
505	if (!name_copy)
506		return -ENOMEM;
507
508	/* create folders for each dirname token, then symlink for basename */
509	while ((tok = strsep(&p, "/")) && *tok) {
510
511		/* last (basename) token? If so, add symlink here */
512		if (!p || !*p) {
513			ret = sysfs_create_link(&dir->kobj, target, tok);
514			break;
515		}
516
517		/* does the current dir contain an item named after tok ? */
518		ko = kset_find_obj(dir, tok);
519		if (ko) {
520			/* drop reference added by kset_find_obj */
521			kobject_put(ko);
522
523			/* ko MUST be a kset - we're about to use it as one ! */
524			if (ko->ktype != dir->kobj.ktype) {
525				ret = -EINVAL;
526				break;
527			}
528
529			/* descend into already existing subdirectory */
530			dir = to_kset(ko);
531		} else {
532			/* create new subdirectory kset */
533			subdir = kzalloc(sizeof(struct kset), GFP_KERNEL);
534			if (!subdir) {
535				ret = -ENOMEM;
536				break;
537			}
538			subdir->kobj.kset = dir;
539			subdir->kobj.ktype = dir->kobj.ktype;
540			ret = kobject_set_name(&subdir->kobj, "%s", tok);
541			if (ret) {
542				kfree(subdir);
543				break;
544			}
545			ret = kset_register(subdir);
546			if (ret) {
547				kfree(subdir);
548				break;
549			}
550
551			/* descend into newly created subdirectory */
552			dir = subdir;
553		}
554	}
555
556	/* we're done with cloned copy of name */
557	kfree(name_copy);
558	return ret;
559}
560
561/* recursively unregister fw_cfg/by_name/ kset directory tree */
562static void fw_cfg_kset_unregister_recursive(struct kset *kset)
563{
564	struct kobject *k, *next;
565
566	list_for_each_entry_safe(k, next, &kset->list, entry)
567		/* all set members are ksets too, but check just in case... */
568		if (k->ktype == kset->kobj.ktype)
569			fw_cfg_kset_unregister_recursive(to_kset(k));
570
571	/* symlinks are cleanly and automatically removed with the directory */
572	kset_unregister(kset);
573}
574
575/* kobjects & kset representing top-level, by_key, and by_name folders */
576static struct kobject *fw_cfg_top_ko;
577static struct kobject *fw_cfg_sel_ko;
578static struct kset *fw_cfg_fname_kset;
579
580/* register an individual fw_cfg file */
581static int fw_cfg_register_file(const struct fw_cfg_file *f)
582{
583	int err;
584	struct fw_cfg_sysfs_entry *entry;
585
586#ifdef CONFIG_CRASH_CORE
587	if (fw_cfg_dma_enabled() &&
588		strcmp(f->name, FW_CFG_VMCOREINFO_FILENAME) == 0 &&
589		!is_kdump_kernel()) {
590		if (fw_cfg_write_vmcoreinfo(f) < 0)
591			pr_warn("fw_cfg: failed to write vmcoreinfo");
592	}
593#endif
594
595	/* allocate new entry */
596	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
597	if (!entry)
598		return -ENOMEM;
599
600	/* set file entry information */
601	entry->size = be32_to_cpu(f->size);
602	entry->select = be16_to_cpu(f->select);
603	strscpy(entry->name, f->name, FW_CFG_MAX_FILE_PATH);
604
605	/* register entry under "/sys/firmware/qemu_fw_cfg/by_key/" */
606	err = kobject_init_and_add(&entry->kobj, &fw_cfg_sysfs_entry_ktype,
607				   fw_cfg_sel_ko, "%d", entry->select);
608	if (err)
609		goto err_put_entry;
 
 
610
611	/* add raw binary content access */
612	err = sysfs_create_bin_file(&entry->kobj, &fw_cfg_sysfs_attr_raw);
613	if (err)
614		goto err_del_entry;
615
616	/* try adding "/sys/firmware/qemu_fw_cfg/by_name/" symlink */
617	fw_cfg_build_symlink(fw_cfg_fname_kset, &entry->kobj, entry->name);
618
619	/* success, add entry to global cache */
620	fw_cfg_sysfs_cache_enlist(entry);
621	return 0;
622
623err_del_entry:
624	kobject_del(&entry->kobj);
625err_put_entry:
626	kobject_put(&entry->kobj);
627	return err;
628}
629
630/* iterate over all fw_cfg directory entries, registering each one */
631static int fw_cfg_register_dir_entries(void)
632{
633	int ret = 0;
634	__be32 files_count;
635	u32 count, i;
636	struct fw_cfg_file *dir;
637	size_t dir_size;
638
639	ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, &files_count,
640			0, sizeof(files_count));
641	if (ret < 0)
642		return ret;
643
644	count = be32_to_cpu(files_count);
645	dir_size = count * sizeof(struct fw_cfg_file);
646
647	dir = kmalloc(dir_size, GFP_KERNEL);
648	if (!dir)
649		return -ENOMEM;
650
651	ret = fw_cfg_read_blob(FW_CFG_FILE_DIR, dir,
652			sizeof(files_count), dir_size);
653	if (ret < 0)
654		goto end;
655
656	for (i = 0; i < count; i++) {
657		ret = fw_cfg_register_file(&dir[i]);
658		if (ret)
659			break;
660	}
661
662end:
663	kfree(dir);
664	return ret;
665}
666
667/* unregister top-level or by_key folder */
668static inline void fw_cfg_kobj_cleanup(struct kobject *kobj)
669{
670	kobject_del(kobj);
671	kobject_put(kobj);
672}
673
674static int fw_cfg_sysfs_probe(struct platform_device *pdev)
675{
676	int err;
677	__le32 rev;
678
679	/* NOTE: If we supported multiple fw_cfg devices, we'd first create
680	 * a subdirectory named after e.g. pdev->id, then hang per-device
681	 * by_key (and by_name) subdirectories underneath it. However, only
682	 * one fw_cfg device exist system-wide, so if one was already found
683	 * earlier, we might as well stop here.
684	 */
685	if (fw_cfg_sel_ko)
686		return -EBUSY;
687
688	/* create by_key and by_name subdirs of /sys/firmware/qemu_fw_cfg/ */
689	err = -ENOMEM;
690	fw_cfg_sel_ko = kobject_create_and_add("by_key", fw_cfg_top_ko);
691	if (!fw_cfg_sel_ko)
692		goto err_sel;
693	fw_cfg_fname_kset = kset_create_and_add("by_name", NULL, fw_cfg_top_ko);
694	if (!fw_cfg_fname_kset)
695		goto err_name;
696
697	/* initialize fw_cfg device i/o from platform data */
698	err = fw_cfg_do_platform_probe(pdev);
699	if (err)
700		goto err_probe;
701
702	/* get revision number, add matching top-level attribute */
703	err = fw_cfg_read_blob(FW_CFG_ID, &rev, 0, sizeof(rev));
704	if (err < 0)
705		goto err_probe;
706
707	fw_cfg_rev = le32_to_cpu(rev);
708	err = sysfs_create_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
709	if (err)
710		goto err_rev;
711
712	/* process fw_cfg file directory entry, registering each file */
713	err = fw_cfg_register_dir_entries();
714	if (err)
715		goto err_dir;
716
717	/* success */
718	pr_debug("fw_cfg: loaded.\n");
719	return 0;
720
721err_dir:
722	fw_cfg_sysfs_cache_cleanup();
723	sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
724err_rev:
725	fw_cfg_io_cleanup();
726err_probe:
727	fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset);
728err_name:
729	fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
730err_sel:
731	return err;
732}
733
734static void fw_cfg_sysfs_remove(struct platform_device *pdev)
735{
736	pr_debug("fw_cfg: unloading.\n");
737	fw_cfg_sysfs_cache_cleanup();
738	sysfs_remove_file(fw_cfg_top_ko, &fw_cfg_rev_attr.attr);
739	fw_cfg_io_cleanup();
740	fw_cfg_kset_unregister_recursive(fw_cfg_fname_kset);
741	fw_cfg_kobj_cleanup(fw_cfg_sel_ko);
 
742}
743
744static const struct of_device_id fw_cfg_sysfs_mmio_match[] = {
745	{ .compatible = "qemu,fw-cfg-mmio", },
746	{},
747};
748MODULE_DEVICE_TABLE(of, fw_cfg_sysfs_mmio_match);
749
750#ifdef CONFIG_ACPI
751static const struct acpi_device_id fw_cfg_sysfs_acpi_match[] = {
752	{ FW_CFG_ACPI_DEVICE_ID, },
753	{},
754};
755MODULE_DEVICE_TABLE(acpi, fw_cfg_sysfs_acpi_match);
756#endif
757
758static struct platform_driver fw_cfg_sysfs_driver = {
759	.probe = fw_cfg_sysfs_probe,
760	.remove_new = fw_cfg_sysfs_remove,
761	.driver = {
762		.name = "fw_cfg",
763		.of_match_table = fw_cfg_sysfs_mmio_match,
764		.acpi_match_table = ACPI_PTR(fw_cfg_sysfs_acpi_match),
765	},
766};
767
768#ifdef CONFIG_FW_CFG_SYSFS_CMDLINE
769
770static struct platform_device *fw_cfg_cmdline_dev;
771
772/* this probably belongs in e.g. include/linux/types.h,
773 * but right now we are the only ones doing it...
774 */
775#ifdef CONFIG_PHYS_ADDR_T_64BIT
776#define __PHYS_ADDR_PREFIX "ll"
777#else
778#define __PHYS_ADDR_PREFIX ""
779#endif
780
781/* use special scanf/printf modifier for phys_addr_t, resource_size_t */
782#define PH_ADDR_SCAN_FMT "@%" __PHYS_ADDR_PREFIX "i%n" \
783			 ":%" __PHYS_ADDR_PREFIX "i" \
784			 ":%" __PHYS_ADDR_PREFIX "i%n" \
785			 ":%" __PHYS_ADDR_PREFIX "i%n"
786
787#define PH_ADDR_PR_1_FMT "0x%" __PHYS_ADDR_PREFIX "x@" \
788			 "0x%" __PHYS_ADDR_PREFIX "x"
789
790#define PH_ADDR_PR_3_FMT PH_ADDR_PR_1_FMT \
791			 ":%" __PHYS_ADDR_PREFIX "u" \
792			 ":%" __PHYS_ADDR_PREFIX "u"
793
794#define PH_ADDR_PR_4_FMT PH_ADDR_PR_3_FMT \
795			 ":%" __PHYS_ADDR_PREFIX "u"
796
797static int fw_cfg_cmdline_set(const char *arg, const struct kernel_param *kp)
798{
799	struct resource res[4] = {};
800	char *str;
801	phys_addr_t base;
802	resource_size_t size, ctrl_off, data_off, dma_off;
803	int processed, consumed = 0;
804
805	/* only one fw_cfg device can exist system-wide, so if one
806	 * was processed on the command line already, we might as
807	 * well stop here.
808	 */
809	if (fw_cfg_cmdline_dev) {
810		/* avoid leaking previously registered device */
811		platform_device_unregister(fw_cfg_cmdline_dev);
812		return -EINVAL;
813	}
814
815	/* consume "<size>" portion of command line argument */
816	size = memparse(arg, &str);
817
818	/* get "@<base>[:<ctrl_off>:<data_off>[:<dma_off>]]" chunks */
819	processed = sscanf(str, PH_ADDR_SCAN_FMT,
820			   &base, &consumed,
821			   &ctrl_off, &data_off, &consumed,
822			   &dma_off, &consumed);
823
824	/* sscanf() must process precisely 1, 3 or 4 chunks:
825	 * <base> is mandatory, optionally followed by <ctrl_off>
826	 * and <data_off>, and <dma_off>;
827	 * there must be no extra characters after the last chunk,
828	 * so str[consumed] must be '\0'.
829	 */
830	if (str[consumed] ||
831	    (processed != 1 && processed != 3 && processed != 4))
832		return -EINVAL;
833
834	res[0].start = base;
835	res[0].end = base + size - 1;
836	res[0].flags = !strcmp(kp->name, "mmio") ? IORESOURCE_MEM :
837						   IORESOURCE_IO;
838
839	/* insert register offsets, if provided */
840	if (processed > 1) {
841		res[1].name = "ctrl";
842		res[1].start = ctrl_off;
843		res[1].flags = IORESOURCE_REG;
844		res[2].name = "data";
845		res[2].start = data_off;
846		res[2].flags = IORESOURCE_REG;
847	}
848	if (processed > 3) {
849		res[3].name = "dma";
850		res[3].start = dma_off;
851		res[3].flags = IORESOURCE_REG;
852	}
853
854	/* "processed" happens to nicely match the number of resources
855	 * we need to pass in to this platform device.
856	 */
857	fw_cfg_cmdline_dev = platform_device_register_simple("fw_cfg",
858					PLATFORM_DEVID_NONE, res, processed);
859
860	return PTR_ERR_OR_ZERO(fw_cfg_cmdline_dev);
861}
862
863static int fw_cfg_cmdline_get(char *buf, const struct kernel_param *kp)
864{
865	/* stay silent if device was not configured via the command
866	 * line, or if the parameter name (ioport/mmio) doesn't match
867	 * the device setting
868	 */
869	if (!fw_cfg_cmdline_dev ||
870	    (!strcmp(kp->name, "mmio") ^
871	     (fw_cfg_cmdline_dev->resource[0].flags == IORESOURCE_MEM)))
872		return 0;
873
874	switch (fw_cfg_cmdline_dev->num_resources) {
875	case 1:
876		return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_1_FMT,
877				resource_size(&fw_cfg_cmdline_dev->resource[0]),
878				fw_cfg_cmdline_dev->resource[0].start);
879	case 3:
880		return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_3_FMT,
881				resource_size(&fw_cfg_cmdline_dev->resource[0]),
882				fw_cfg_cmdline_dev->resource[0].start,
883				fw_cfg_cmdline_dev->resource[1].start,
884				fw_cfg_cmdline_dev->resource[2].start);
885	case 4:
886		return snprintf(buf, PAGE_SIZE, PH_ADDR_PR_4_FMT,
887				resource_size(&fw_cfg_cmdline_dev->resource[0]),
888				fw_cfg_cmdline_dev->resource[0].start,
889				fw_cfg_cmdline_dev->resource[1].start,
890				fw_cfg_cmdline_dev->resource[2].start,
891				fw_cfg_cmdline_dev->resource[3].start);
892	}
893
894	/* Should never get here */
895	WARN(1, "Unexpected number of resources: %d\n",
896		fw_cfg_cmdline_dev->num_resources);
897	return 0;
898}
899
900static const struct kernel_param_ops fw_cfg_cmdline_param_ops = {
901	.set = fw_cfg_cmdline_set,
902	.get = fw_cfg_cmdline_get,
903};
904
905device_param_cb(ioport, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
906device_param_cb(mmio, &fw_cfg_cmdline_param_ops, NULL, S_IRUSR);
907
908#endif /* CONFIG_FW_CFG_SYSFS_CMDLINE */
909
910static int __init fw_cfg_sysfs_init(void)
911{
912	int ret;
913
914	/* create /sys/firmware/qemu_fw_cfg/ top level directory */
915	fw_cfg_top_ko = kobject_create_and_add("qemu_fw_cfg", firmware_kobj);
916	if (!fw_cfg_top_ko)
917		return -ENOMEM;
918
919	ret = platform_driver_register(&fw_cfg_sysfs_driver);
920	if (ret)
921		fw_cfg_kobj_cleanup(fw_cfg_top_ko);
922
923	return ret;
924}
925
926static void __exit fw_cfg_sysfs_exit(void)
927{
928	platform_driver_unregister(&fw_cfg_sysfs_driver);
929
930#ifdef CONFIG_FW_CFG_SYSFS_CMDLINE
931	platform_device_unregister(fw_cfg_cmdline_dev);
932#endif
933
934	/* clean up /sys/firmware/qemu_fw_cfg/ */
935	fw_cfg_kobj_cleanup(fw_cfg_top_ko);
936}
937
938module_init(fw_cfg_sysfs_init);
939module_exit(fw_cfg_sysfs_exit);