summaryrefslogtreecommitdiffstats
path: root/drivers/usb/gadget/storage_common.c
blob: ff205a7bc55c9aefcd98994aeb3c25fe4c37eb28 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
/*
 * storage_common.c -- Common definitions for mass storage functionality
 *
 * Copyright (C) 2003-2008 Alan Stern
 * Copyeight (C) 2009 Samsung Electronics
 * Author: Michal Nazarewicz (mina86@mina86.com)
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

/*
 * This file requires the following identifiers used in USB strings to
 * be defined (each of type pointer to char):
 *  - fsg_string_interface    -- name of the interface
 */

/*
 * When USB_GADGET_DEBUG_FILES is defined the module param num_buffers
 * sets the number of pipeline buffers (length of the fsg_buffhd array).
 * The valid range of num_buffers is: num >= 2 && num <= 4.
 */

#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/usb/composite.h>

#include "storage_common.h"

/* There is only one interface. */

struct usb_interface_descriptor fsg_intf_desc = {
	.bLength =		sizeof fsg_intf_desc,
	.bDescriptorType =	USB_DT_INTERFACE,

	.bNumEndpoints =	2,		/* Adjusted during fsg_bind() */
	.bInterfaceClass =	USB_CLASS_MASS_STORAGE,
	.bInterfaceSubClass =	USB_SC_SCSI,	/* Adjusted during fsg_bind() */
	.bInterfaceProtocol =	USB_PR_BULK,	/* Adjusted during fsg_bind() */
	.iInterface =		FSG_STRING_INTERFACE,
};
EXPORT_SYMBOL_GPL(fsg_intf_desc);

/*
 * Three full-speed endpoint descriptors: bulk-in, bulk-out, and
 * interrupt-in.
 */

struct usb_endpoint_descriptor fsg_fs_bulk_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_IN,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	/* wMaxPacketSize set by autoconfiguration */
};
EXPORT_SYMBOL_GPL(fsg_fs_bulk_in_desc);

struct usb_endpoint_descriptor fsg_fs_bulk_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	.bEndpointAddress =	USB_DIR_OUT,
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	/* wMaxPacketSize set by autoconfiguration */
};
EXPORT_SYMBOL_GPL(fsg_fs_bulk_out_desc);

struct usb_descriptor_header *fsg_fs_function[] = {
	(struct usb_descriptor_header *) &fsg_intf_desc,
	(struct usb_descriptor_header *) &fsg_fs_bulk_in_desc,
	(struct usb_descriptor_header *) &fsg_fs_bulk_out_desc,
	NULL,
};
EXPORT_SYMBOL_GPL(fsg_fs_function);


/*
 * USB 2.0 devices need to expose both high speed and full speed
 * descriptors, unless they only run at full speed.
 *
 * That means alternate endpoint descriptors (bigger packets)
 * and a "device qualifier" ... plus more construction options
 * for the configuration descriptor.
 */
struct usb_endpoint_descriptor fsg_hs_bulk_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	/* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(512),
};
EXPORT_SYMBOL_GPL(fsg_hs_bulk_in_desc);

struct usb_endpoint_descriptor fsg_hs_bulk_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	/* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(512),
	.bInterval =		1,	/* NAK every 1 uframe */
};
EXPORT_SYMBOL_GPL(fsg_hs_bulk_out_desc);


struct usb_descriptor_header *fsg_hs_function[] = {
	(struct usb_descriptor_header *) &fsg_intf_desc,
	(struct usb_descriptor_header *) &fsg_hs_bulk_in_desc,
	(struct usb_descriptor_header *) &fsg_hs_bulk_out_desc,
	NULL,
};
EXPORT_SYMBOL_GPL(fsg_hs_function);

struct usb_endpoint_descriptor fsg_ss_bulk_in_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	/* bEndpointAddress copied from fs_bulk_in_desc during fsg_bind() */
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(1024),
};
EXPORT_SYMBOL_GPL(fsg_ss_bulk_in_desc);

struct usb_ss_ep_comp_descriptor fsg_ss_bulk_in_comp_desc = {
	.bLength =		sizeof(fsg_ss_bulk_in_comp_desc),
	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,

	/*.bMaxBurst =		DYNAMIC, */
};
EXPORT_SYMBOL_GPL(fsg_ss_bulk_in_comp_desc);

struct usb_endpoint_descriptor fsg_ss_bulk_out_desc = {
	.bLength =		USB_DT_ENDPOINT_SIZE,
	.bDescriptorType =	USB_DT_ENDPOINT,

	/* bEndpointAddress copied from fs_bulk_out_desc during fsg_bind() */
	.bmAttributes =		USB_ENDPOINT_XFER_BULK,
	.wMaxPacketSize =	cpu_to_le16(1024),
};
EXPORT_SYMBOL_GPL(fsg_ss_bulk_out_desc);

struct usb_ss_ep_comp_descriptor fsg_ss_bulk_out_comp_desc = {
	.bLength =		sizeof(fsg_ss_bulk_in_comp_desc),
	.bDescriptorType =	USB_DT_SS_ENDPOINT_COMP,

	/*.bMaxBurst =		DYNAMIC, */
};
EXPORT_SYMBOL_GPL(fsg_ss_bulk_out_comp_desc);

struct usb_descriptor_header *fsg_ss_function[] = {
	(struct usb_descriptor_header *) &fsg_intf_desc,
	(struct usb_descriptor_header *) &fsg_ss_bulk_in_desc,
	(struct usb_descriptor_header *) &fsg_ss_bulk_in_comp_desc,
	(struct usb_descriptor_header *) &fsg_ss_bulk_out_desc,
	(struct usb_descriptor_header *) &fsg_ss_bulk_out_comp_desc,
	NULL,
};
EXPORT_SYMBOL_GPL(fsg_ss_function);


 /*-------------------------------------------------------------------------*/

/*
 * If the next two routines are called while the gadget is registered,
 * the caller must own fsg->filesem for writing.
 */

void fsg_lun_close(struct fsg_lun *curlun)
{
	if (curlun->filp) {
		LDBG(curlun, "close backing file\n");
		fput(curlun->filp);
		curlun->filp = NULL;
	}
}
EXPORT_SYMBOL_GPL(fsg_lun_close);

int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
{
	int				ro;
	struct file			*filp = NULL;
	int				rc = -EINVAL;
	struct inode			*inode = NULL;
	loff_t				size;
	loff_t				num_sectors;
	loff_t				min_sectors;
	unsigned int			blkbits;
	unsigned int			blksize;

	/* R/W if we can, R/O if we must */
	ro = curlun->initially_ro;
	if (!ro) {
		filp = filp_open(filename, O_RDWR | O_LARGEFILE, 0);
		if (PTR_ERR(filp) == -EROFS || PTR_ERR(filp) == -EACCES)
			ro = 1;
	}
	if (ro)
		filp = filp_open(filename, O_RDONLY | O_LARGEFILE, 0);
	if (IS_ERR(filp)) {
		LINFO(curlun, "unable to open backing file: %s\n", filename);
		return PTR_ERR(filp);
	}

	if (!(filp->f_mode & FMODE_WRITE))
		ro = 1;

	inode = file_inode(filp);
	if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
		LINFO(curlun, "invalid file type: %s\n", filename);
		goto out;
	}

	/*
	 * If we can't read the file, it's no good.
	 * If we can't write the file, use it read-only.
	 */
	if (!(filp->f_op->read || filp->f_op->aio_read)) {
		LINFO(curlun, "file not readable: %s\n", filename);
		goto out;
	}
	if (!(filp->f_op->write || filp->f_op->aio_write))
		ro = 1;

	size = i_size_read(inode->i_mapping->host);
	if (size < 0) {
		LINFO(curlun, "unable to find file size: %s\n", filename);
		rc = (int) size;
		goto out;
	}

	if (curlun->cdrom) {
		blksize = 2048;
		blkbits = 11;
	} else if (inode->i_bdev) {
		blksize = bdev_logical_block_size(inode->i_bdev);
		blkbits = blksize_bits(blksize);
	} else {
		blksize = 512;
		blkbits = 9;
	}

	num_sectors = size >> blkbits; /* File size in logic-block-size blocks */
	min_sectors = 1;
	if (curlun->cdrom) {
		min_sectors = 300;	/* Smallest track is 300 frames */
		if (num_sectors >= 256*60*75) {
			num_sectors = 256*60*75 - 1;
			LINFO(curlun, "file too big: %s\n", filename);
			LINFO(curlun, "using only first %d blocks\n",
					(int) num_sectors);
		}
	}
	if (num_sectors < min_sectors) {
		LINFO(curlun, "file too small: %s\n", filename);
		rc = -ETOOSMALL;
		goto out;
	}

	if (fsg_lun_is_open(curlun))
		fsg_lun_close(curlun);

	curlun->blksize = blksize;
	curlun->blkbits = blkbits;
	curlun->ro = ro;
	curlun->filp = filp;
	curlun->file_length = size;
	curlun->num_sectors = num_sectors;
	LDBG(curlun, "open backing file: %s\n", filename);
	return 0;

out:
	fput(filp);
	return rc;
}
EXPORT_SYMBOL_GPL(fsg_lun_open);


/*-------------------------------------------------------------------------*/

/*
 * Sync the file data, don't bother with the metadata.
 * This code was copied from fs/buffer.c:sys_fdatasync().
 */
int fsg_lun_fsync_sub(struct fsg_lun *curlun)
{
	struct file	*filp = curlun->filp;

	if (curlun->ro || !filp)
		return 0;
	return vfs_fsync(filp, 1);
}
EXPORT_SYMBOL_GPL(fsg_lun_fsync_sub);

void store_cdrom_address(u8 *dest, int msf, u32 addr)
{
	if (msf) {
		/* Convert to Minutes-Seconds-Frames */
		addr >>= 2;		/* Convert to 2048-byte frames */
		addr += 2*75;		/* Lead-in occupies 2 seconds */
		dest[3] = addr % 75;	/* Frames */
		addr /= 75;
		dest[2] = addr % 60;	/* Seconds */
		addr /= 60;
		dest[1] = addr;		/* Minutes */
		dest[0] = 0;		/* Reserved */
	} else {
		/* Absolute sector */
		put_unaligned_be32(addr, dest);
	}
}
EXPORT_SYMBOL_GPL(store_cdrom_address);

/*-------------------------------------------------------------------------*/


ssize_t fsg_show_ro(struct fsg_lun *curlun, char *buf)
{
	return sprintf(buf, "%d\n", fsg_lun_is_open(curlun)
				  ? curlun->ro
				  : curlun->initially_ro);
}
EXPORT_SYMBOL_GPL(fsg_show_ro);

ssize_t fsg_show_nofua(struct fsg_lun *curlun, char *buf)
{
	return sprintf(buf, "%u\n", curlun->nofua);
}
EXPORT_SYMBOL_GPL(fsg_show_nofua);

ssize_t fsg_show_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
		      char *buf)
{
	char		*p;
	ssize_t		rc;

	down_read(filesem);
	if (fsg_lun_is_open(curlun)) {	/* Get the complete pathname */
		p = d_path(&curlun->filp->f_path, buf, PAGE_SIZE - 1);
		if (IS_ERR(p))
			rc = PTR_ERR(p);
		else {
			rc = strlen(p);
			memmove(buf, p, rc);
			buf[rc] = '\n';		/* Add a newline */
			buf[++rc] = 0;
		}
	} else {				/* No file, return 0 bytes */
		*buf = 0;
		rc = 0;
	}
	up_read(filesem);
	return rc;
}
EXPORT_SYMBOL_GPL(fsg_show_file);

ssize_t fsg_show_cdrom(struct fsg_lun *curlun, char *buf)
{
	return sprintf(buf, "%u\n", curlun->cdrom);
}
EXPORT_SYMBOL_GPL(fsg_show_cdrom);

ssize_t fsg_show_removable(struct fsg_lun *curlun, char *buf)
{
	return sprintf(buf, "%u\n", curlun->removable);
}
EXPORT_SYMBOL_GPL(fsg_show_removable);

/*
 * The caller must hold fsg->filesem for reading when calling this function.
 */
static ssize_t _fsg_store_ro(struct fsg_lun *curlun, bool ro)
{
	if (fsg_lun_is_open(curlun)) {
		LDBG(curlun, "read-only status change prevented\n");
		return -EBUSY;
	}

	curlun->ro = ro;
	curlun->initially_ro = ro;
	LDBG(curlun, "read-only status set to %d\n", curlun->ro);

	return 0;
}

ssize_t fsg_store_ro(struct fsg_lun *curlun, struct rw_semaphore *filesem,
		     const char *buf, size_t count)
{
	ssize_t		rc;
	bool		ro;

	rc = strtobool(buf, &ro);
	if (rc)
		return rc;

	/*
	 * Allow the write-enable status to change only while the
	 * backing file is closed.
	 */
	down_read(filesem);
	rc = _fsg_store_ro(curlun, ro);
	if (!rc)
		rc = count;
	up_read(filesem);

	return rc;
}
EXPORT_SYMBOL_GPL(fsg_store_ro);

ssize_t fsg_store_nofua(struct fsg_lun *curlun, const char *buf, size_t count)
{
	bool		nofua;
	int		ret;

	ret = strtobool(buf, &nofua);
	if (ret)
		return ret;

	/* Sync data when switching from async mode to sync */
	if (!nofua && curlun->nofua)
		fsg_lun_fsync_sub(curlun);

	curlun->nofua = nofua;

	return count;
}
EXPORT_SYMBOL_GPL(fsg_store_nofua);

ssize_t fsg_store_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
		       const char *buf, size_t count)
{
	int		rc = 0;

	if (curlun->prevent_medium_removal && fsg_lun_is_open(curlun)) {
		LDBG(curlun, "eject attempt prevented\n");
		return -EBUSY;				/* "Door is locked" */
	}

	/* Remove a trailing newline */
	if (count > 0 && buf[count-1] == '\n')
		((char *) buf)[count-1] = 0;		/* Ugh! */

	/* Load new medium */
	down_write(filesem);
	if (count > 0 && buf[0]) {
		/* fsg_lun_open() will close existing file if any. */
		rc = fsg_lun_open(curlun, buf);
		if (rc == 0)
			curlun->unit_attention_data =
					SS_NOT_READY_TO_READY_TRANSITION;
	} else if (fsg_lun_is_open(curlun)) {
		fsg_lun_close(curlun);
		curlun->unit_attention_data = SS_MEDIUM_NOT_PRESENT;
	}
	up_write(filesem);
	return (rc < 0 ? rc : count);
}
EXPORT_SYMBOL_GPL(fsg_store_file);

ssize_t fsg_store_cdrom(struct fsg_lun *curlun, struct rw_semaphore *filesem,
			const char *buf, size_t count)
{
	bool		cdrom;
	int		ret;

	ret = strtobool(buf, &cdrom);
	if (ret)
		return ret;

	down_read(filesem);
	ret = cdrom ? _fsg_store_ro(curlun, true) : 0;

	if (!ret) {
		curlun->cdrom = cdrom;
		ret = count;
	}
	up_read(filesem);

	return ret;
}
EXPORT_SYMBOL_GPL(fsg_store_cdrom);

ssize_t fsg_store_removable(struct fsg_lun *curlun, const char *buf,
			    size_t count)
{
	bool		removable;
	int		ret;

	ret = strtobool(buf, &removable);
	if (ret)
		return ret;

	curlun->removable = removable;

	return count;
}
EXPORT_SYMBOL_GPL(fsg_store_removable);

MODULE_LICENSE("GPL");