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Commit | Line | Data |
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814a8d50 | 1 | /* |
ca632f55 | 2 | * Simple synchronous userspace interface to SPI devices |
814a8d50 AP |
3 | * |
4 | * Copyright (C) 2006 SWAPP | |
5 | * Andrea Paterniani <a.paterniani@swapp-eng.it> | |
6 | * Copyright (C) 2007 David Brownell (simplification, cleanup) | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; either version 2 of the License, or | |
11 | * (at your option) any later version. | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
814a8d50 AP |
17 | */ |
18 | ||
19 | #include <linux/init.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/ioctl.h> | |
22 | #include <linux/fs.h> | |
23 | #include <linux/device.h> | |
b2c8dadd | 24 | #include <linux/err.h> |
814a8d50 AP |
25 | #include <linux/list.h> |
26 | #include <linux/errno.h> | |
27 | #include <linux/mutex.h> | |
28 | #include <linux/slab.h> | |
7d48ec36 | 29 | #include <linux/compat.h> |
880cfd43 MR |
30 | #include <linux/of.h> |
31 | #include <linux/of_device.h> | |
814a8d50 AP |
32 | |
33 | #include <linux/spi/spi.h> | |
34 | #include <linux/spi/spidev.h> | |
35 | ||
95c63cfb | 36 | #include <linux/uaccess.h> |
814a8d50 AP |
37 | |
38 | ||
39 | /* | |
b595076a | 40 | * This supports access to SPI devices using normal userspace I/O calls. |
814a8d50 AP |
41 | * Note that while traditional UNIX/POSIX I/O semantics are half duplex, |
42 | * and often mask message boundaries, full SPI support requires full duplex | |
137f1188 | 43 | * transfers. There are several kinds of internal message boundaries to |
814a8d50 AP |
44 | * handle chipselect management and other protocol options. |
45 | * | |
46 | * SPI has a character major number assigned. We allocate minor numbers | |
47 | * dynamically using a bitmask. You must use hotplug tools, such as udev | |
48 | * (or mdev with busybox) to create and destroy the /dev/spidevB.C device | |
49 | * nodes, since there is no fixed association of minor numbers with any | |
50 | * particular SPI bus or device. | |
51 | */ | |
52 | #define SPIDEV_MAJOR 153 /* assigned */ | |
53 | #define N_SPI_MINORS 32 /* ... up to 256 */ | |
54 | ||
8ae1c924 | 55 | static DECLARE_BITMAP(minors, N_SPI_MINORS); |
814a8d50 AP |
56 | |
57 | ||
6f166e38 | 58 | /* Bit masks for spi_device.mode management. Note that incorrect |
b55f627f DB |
59 | * settings for some settings can cause *lots* of trouble for other |
60 | * devices on a shared bus: | |
6f166e38 | 61 | * |
b55f627f DB |
62 | * - CS_HIGH ... this device will be active when it shouldn't be |
63 | * - 3WIRE ... when active, it won't behave as it should | |
64 | * - NO_CS ... there will be no explicit message boundaries; this | |
65 | * is completely incompatible with the shared bus model | |
66 | * - READY ... transfers may proceed when they shouldn't. | |
67 | * | |
68 | * REVISIT should changing those flags be privileged? | |
6f166e38 AV |
69 | */ |
70 | #define SPI_MODE_MASK (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH \ | |
b55f627f | 71 | | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP \ |
dc64d39b GU |
72 | | SPI_NO_CS | SPI_READY | SPI_TX_DUAL \ |
73 | | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD) | |
814a8d50 AP |
74 | |
75 | struct spidev_data { | |
b2c8dadd | 76 | dev_t devt; |
25d5cb4b | 77 | spinlock_t spi_lock; |
814a8d50 AP |
78 | struct spi_device *spi; |
79 | struct list_head device_entry; | |
80 | ||
865f6d19 | 81 | /* TX/RX buffers are NULL unless this device is open (users > 0) */ |
814a8d50 AP |
82 | struct mutex buf_lock; |
83 | unsigned users; | |
865f6d19 RJ |
84 | u8 *tx_buffer; |
85 | u8 *rx_buffer; | |
91690516 | 86 | u32 speed_hz; |
814a8d50 AP |
87 | }; |
88 | ||
89 | static LIST_HEAD(device_list); | |
90 | static DEFINE_MUTEX(device_list_lock); | |
91 | ||
92 | static unsigned bufsiz = 4096; | |
93 | module_param(bufsiz, uint, S_IRUGO); | |
94 | MODULE_PARM_DESC(bufsiz, "data bytes in biggest supported SPI message"); | |
95 | ||
96 | /*-------------------------------------------------------------------------*/ | |
97 | ||
25d5cb4b DB |
98 | static ssize_t |
99 | spidev_sync(struct spidev_data *spidev, struct spi_message *message) | |
100 | { | |
101 | DECLARE_COMPLETION_ONSTACK(done); | |
102 | int status; | |
98d6f479 | 103 | struct spi_device *spi; |
25d5cb4b DB |
104 | |
105 | spin_lock_irq(&spidev->spi_lock); | |
98d6f479 MS |
106 | spi = spidev->spi; |
107 | spin_unlock_irq(&spidev->spi_lock); | |
108 | ||
109 | if (spi == NULL) | |
25d5cb4b DB |
110 | status = -ESHUTDOWN; |
111 | else | |
98d6f479 MS |
112 | status = spi_sync(spi, message); |
113 | ||
114 | if (status == 0) | |
115 | status = message->actual_length; | |
25d5cb4b | 116 | |
25d5cb4b DB |
117 | return status; |
118 | } | |
119 | ||
120 | static inline ssize_t | |
121 | spidev_sync_write(struct spidev_data *spidev, size_t len) | |
122 | { | |
123 | struct spi_transfer t = { | |
865f6d19 | 124 | .tx_buf = spidev->tx_buffer, |
25d5cb4b | 125 | .len = len, |
91690516 | 126 | .speed_hz = spidev->speed_hz, |
25d5cb4b DB |
127 | }; |
128 | struct spi_message m; | |
129 | ||
130 | spi_message_init(&m); | |
131 | spi_message_add_tail(&t, &m); | |
132 | return spidev_sync(spidev, &m); | |
133 | } | |
134 | ||
135 | static inline ssize_t | |
136 | spidev_sync_read(struct spidev_data *spidev, size_t len) | |
137 | { | |
138 | struct spi_transfer t = { | |
865f6d19 | 139 | .rx_buf = spidev->rx_buffer, |
25d5cb4b | 140 | .len = len, |
91690516 | 141 | .speed_hz = spidev->speed_hz, |
25d5cb4b DB |
142 | }; |
143 | struct spi_message m; | |
144 | ||
145 | spi_message_init(&m); | |
146 | spi_message_add_tail(&t, &m); | |
147 | return spidev_sync(spidev, &m); | |
148 | } | |
149 | ||
150 | /*-------------------------------------------------------------------------*/ | |
151 | ||
814a8d50 AP |
152 | /* Read-only message with current device setup */ |
153 | static ssize_t | |
154 | spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) | |
155 | { | |
156 | struct spidev_data *spidev; | |
814a8d50 AP |
157 | ssize_t status = 0; |
158 | ||
159 | /* chipselect only toggles at start or end of operation */ | |
160 | if (count > bufsiz) | |
161 | return -EMSGSIZE; | |
162 | ||
163 | spidev = filp->private_data; | |
814a8d50 AP |
164 | |
165 | mutex_lock(&spidev->buf_lock); | |
25d5cb4b | 166 | status = spidev_sync_read(spidev, count); |
4b1295b0 | 167 | if (status > 0) { |
814a8d50 AP |
168 | unsigned long missing; |
169 | ||
865f6d19 | 170 | missing = copy_to_user(buf, spidev->rx_buffer, status); |
4b1295b0 | 171 | if (missing == status) |
814a8d50 AP |
172 | status = -EFAULT; |
173 | else | |
4b1295b0 | 174 | status = status - missing; |
814a8d50 AP |
175 | } |
176 | mutex_unlock(&spidev->buf_lock); | |
177 | ||
178 | return status; | |
179 | } | |
180 | ||
181 | /* Write-only message with current device setup */ | |
182 | static ssize_t | |
183 | spidev_write(struct file *filp, const char __user *buf, | |
184 | size_t count, loff_t *f_pos) | |
185 | { | |
186 | struct spidev_data *spidev; | |
814a8d50 AP |
187 | ssize_t status = 0; |
188 | unsigned long missing; | |
189 | ||
190 | /* chipselect only toggles at start or end of operation */ | |
191 | if (count > bufsiz) | |
192 | return -EMSGSIZE; | |
193 | ||
194 | spidev = filp->private_data; | |
814a8d50 AP |
195 | |
196 | mutex_lock(&spidev->buf_lock); | |
865f6d19 | 197 | missing = copy_from_user(spidev->tx_buffer, buf, count); |
95c63cfb | 198 | if (missing == 0) |
25d5cb4b | 199 | status = spidev_sync_write(spidev, count); |
95c63cfb | 200 | else |
814a8d50 AP |
201 | status = -EFAULT; |
202 | mutex_unlock(&spidev->buf_lock); | |
203 | ||
204 | return status; | |
205 | } | |
206 | ||
207 | static int spidev_message(struct spidev_data *spidev, | |
208 | struct spi_ioc_transfer *u_xfers, unsigned n_xfers) | |
209 | { | |
210 | struct spi_message msg; | |
211 | struct spi_transfer *k_xfers; | |
212 | struct spi_transfer *k_tmp; | |
213 | struct spi_ioc_transfer *u_tmp; | |
9a12bff7 | 214 | unsigned n, total, tx_total, rx_total; |
865f6d19 | 215 | u8 *tx_buf, *rx_buf; |
814a8d50 AP |
216 | int status = -EFAULT; |
217 | ||
218 | spi_message_init(&msg); | |
219 | k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); | |
220 | if (k_xfers == NULL) | |
221 | return -ENOMEM; | |
222 | ||
223 | /* Construct spi_message, copying any tx data to bounce buffer. | |
224 | * We walk the array of user-provided transfers, using each one | |
225 | * to initialize a kernel version of the same transfer. | |
226 | */ | |
865f6d19 RJ |
227 | tx_buf = spidev->tx_buffer; |
228 | rx_buf = spidev->rx_buffer; | |
814a8d50 | 229 | total = 0; |
9a12bff7 IA |
230 | tx_total = 0; |
231 | rx_total = 0; | |
814a8d50 AP |
232 | for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; |
233 | n; | |
234 | n--, k_tmp++, u_tmp++) { | |
235 | k_tmp->len = u_tmp->len; | |
236 | ||
da90fa8f | 237 | total += k_tmp->len; |
9a12bff7 IA |
238 | /* Since the function returns the total length of transfers |
239 | * on success, restrict the total to positive int values to | |
f20fbaad IA |
240 | * avoid the return value looking like an error. Also check |
241 | * each transfer length to avoid arithmetic overflow. | |
9a12bff7 | 242 | */ |
f20fbaad | 243 | if (total > INT_MAX || k_tmp->len > INT_MAX) { |
da90fa8f DP |
244 | status = -EMSGSIZE; |
245 | goto done; | |
246 | } | |
247 | ||
814a8d50 | 248 | if (u_tmp->rx_buf) { |
9a12bff7 IA |
249 | /* this transfer needs space in RX bounce buffer */ |
250 | rx_total += k_tmp->len; | |
251 | if (rx_total > bufsiz) { | |
252 | status = -EMSGSIZE; | |
253 | goto done; | |
254 | } | |
865f6d19 | 255 | k_tmp->rx_buf = rx_buf; |
96ddbf50 | 256 | if (!access_ok(VERIFY_WRITE, (u8 __user *) |
142956af | 257 | (uintptr_t) u_tmp->rx_buf, |
96ddbf50 | 258 | u_tmp->len)) |
814a8d50 | 259 | goto done; |
9a12bff7 | 260 | rx_buf += k_tmp->len; |
814a8d50 AP |
261 | } |
262 | if (u_tmp->tx_buf) { | |
9a12bff7 IA |
263 | /* this transfer needs space in TX bounce buffer */ |
264 | tx_total += k_tmp->len; | |
265 | if (tx_total > bufsiz) { | |
266 | status = -EMSGSIZE; | |
267 | goto done; | |
268 | } | |
865f6d19 RJ |
269 | k_tmp->tx_buf = tx_buf; |
270 | if (copy_from_user(tx_buf, (const u8 __user *) | |
142956af | 271 | (uintptr_t) u_tmp->tx_buf, |
814a8d50 AP |
272 | u_tmp->len)) |
273 | goto done; | |
9a12bff7 | 274 | tx_buf += k_tmp->len; |
814a8d50 | 275 | } |
814a8d50 AP |
276 | |
277 | k_tmp->cs_change = !!u_tmp->cs_change; | |
dc64d39b GU |
278 | k_tmp->tx_nbits = u_tmp->tx_nbits; |
279 | k_tmp->rx_nbits = u_tmp->rx_nbits; | |
814a8d50 AP |
280 | k_tmp->bits_per_word = u_tmp->bits_per_word; |
281 | k_tmp->delay_usecs = u_tmp->delay_usecs; | |
282 | k_tmp->speed_hz = u_tmp->speed_hz; | |
91690516 MB |
283 | if (!k_tmp->speed_hz) |
284 | k_tmp->speed_hz = spidev->speed_hz; | |
814a8d50 | 285 | #ifdef VERBOSE |
41df70d9 | 286 | dev_dbg(&spidev->spi->dev, |
814a8d50 AP |
287 | " xfer len %zd %s%s%s%dbits %u usec %uHz\n", |
288 | u_tmp->len, | |
289 | u_tmp->rx_buf ? "rx " : "", | |
290 | u_tmp->tx_buf ? "tx " : "", | |
291 | u_tmp->cs_change ? "cs " : "", | |
41df70d9 | 292 | u_tmp->bits_per_word ? : spidev->spi->bits_per_word, |
814a8d50 | 293 | u_tmp->delay_usecs, |
41df70d9 | 294 | u_tmp->speed_hz ? : spidev->spi->max_speed_hz); |
814a8d50 AP |
295 | #endif |
296 | spi_message_add_tail(k_tmp, &msg); | |
297 | } | |
298 | ||
25d5cb4b | 299 | status = spidev_sync(spidev, &msg); |
814a8d50 AP |
300 | if (status < 0) |
301 | goto done; | |
302 | ||
303 | /* copy any rx data out of bounce buffer */ | |
865f6d19 | 304 | rx_buf = spidev->rx_buffer; |
814a8d50 AP |
305 | for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) { |
306 | if (u_tmp->rx_buf) { | |
4917d927 | 307 | if (__copy_to_user((u8 __user *) |
865f6d19 | 308 | (uintptr_t) u_tmp->rx_buf, rx_buf, |
814a8d50 AP |
309 | u_tmp->len)) { |
310 | status = -EFAULT; | |
311 | goto done; | |
312 | } | |
9a12bff7 | 313 | rx_buf += u_tmp->len; |
814a8d50 | 314 | } |
814a8d50 AP |
315 | } |
316 | status = total; | |
317 | ||
318 | done: | |
814a8d50 AP |
319 | kfree(k_xfers); |
320 | return status; | |
321 | } | |
322 | ||
7782a1a9 IA |
323 | static struct spi_ioc_transfer * |
324 | spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc, | |
325 | unsigned *n_ioc) | |
326 | { | |
327 | struct spi_ioc_transfer *ioc; | |
328 | u32 tmp; | |
329 | ||
330 | /* Check type, command number and direction */ | |
331 | if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC | |
332 | || _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) | |
333 | || _IOC_DIR(cmd) != _IOC_WRITE) | |
334 | return ERR_PTR(-ENOTTY); | |
335 | ||
336 | tmp = _IOC_SIZE(cmd); | |
337 | if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) | |
338 | return ERR_PTR(-EINVAL); | |
339 | *n_ioc = tmp / sizeof(struct spi_ioc_transfer); | |
340 | if (*n_ioc == 0) | |
341 | return NULL; | |
342 | ||
343 | /* copy into scratch area */ | |
344 | ioc = kmalloc(tmp, GFP_KERNEL); | |
345 | if (!ioc) | |
346 | return ERR_PTR(-ENOMEM); | |
347 | if (__copy_from_user(ioc, u_ioc, tmp)) { | |
348 | kfree(ioc); | |
349 | return ERR_PTR(-EFAULT); | |
350 | } | |
351 | return ioc; | |
352 | } | |
353 | ||
4ef754b7 AC |
354 | static long |
355 | spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
814a8d50 AP |
356 | { |
357 | int err = 0; | |
358 | int retval = 0; | |
359 | struct spidev_data *spidev; | |
360 | struct spi_device *spi; | |
361 | u32 tmp; | |
362 | unsigned n_ioc; | |
363 | struct spi_ioc_transfer *ioc; | |
364 | ||
365 | /* Check type and command number */ | |
366 | if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) | |
367 | return -ENOTTY; | |
368 | ||
369 | /* Check access direction once here; don't repeat below. | |
370 | * IOC_DIR is from the user perspective, while access_ok is | |
371 | * from the kernel perspective; so they look reversed. | |
372 | */ | |
373 | if (_IOC_DIR(cmd) & _IOC_READ) | |
374 | err = !access_ok(VERIFY_WRITE, | |
375 | (void __user *)arg, _IOC_SIZE(cmd)); | |
376 | if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE) | |
377 | err = !access_ok(VERIFY_READ, | |
378 | (void __user *)arg, _IOC_SIZE(cmd)); | |
379 | if (err) | |
380 | return -EFAULT; | |
381 | ||
25d5cb4b DB |
382 | /* guard against device removal before, or while, |
383 | * we issue this ioctl. | |
384 | */ | |
814a8d50 | 385 | spidev = filp->private_data; |
25d5cb4b DB |
386 | spin_lock_irq(&spidev->spi_lock); |
387 | spi = spi_dev_get(spidev->spi); | |
388 | spin_unlock_irq(&spidev->spi_lock); | |
389 | ||
390 | if (spi == NULL) | |
391 | return -ESHUTDOWN; | |
814a8d50 | 392 | |
4ef754b7 AC |
393 | /* use the buffer lock here for triple duty: |
394 | * - prevent I/O (from us) so calling spi_setup() is safe; | |
395 | * - prevent concurrent SPI_IOC_WR_* from morphing | |
396 | * data fields while SPI_IOC_RD_* reads them; | |
397 | * - SPI_IOC_MESSAGE needs the buffer locked "normally". | |
398 | */ | |
399 | mutex_lock(&spidev->buf_lock); | |
400 | ||
814a8d50 AP |
401 | switch (cmd) { |
402 | /* read requests */ | |
403 | case SPI_IOC_RD_MODE: | |
404 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
405 | (__u8 __user *)arg); | |
406 | break; | |
dc64d39b GU |
407 | case SPI_IOC_RD_MODE32: |
408 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
409 | (__u32 __user *)arg); | |
410 | break; | |
814a8d50 AP |
411 | case SPI_IOC_RD_LSB_FIRST: |
412 | retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, | |
413 | (__u8 __user *)arg); | |
414 | break; | |
415 | case SPI_IOC_RD_BITS_PER_WORD: | |
416 | retval = __put_user(spi->bits_per_word, (__u8 __user *)arg); | |
417 | break; | |
418 | case SPI_IOC_RD_MAX_SPEED_HZ: | |
91690516 | 419 | retval = __put_user(spidev->speed_hz, (__u32 __user *)arg); |
814a8d50 AP |
420 | break; |
421 | ||
422 | /* write requests */ | |
423 | case SPI_IOC_WR_MODE: | |
dc64d39b GU |
424 | case SPI_IOC_WR_MODE32: |
425 | if (cmd == SPI_IOC_WR_MODE) | |
426 | retval = __get_user(tmp, (u8 __user *)arg); | |
427 | else | |
428 | retval = __get_user(tmp, (u32 __user *)arg); | |
814a8d50 | 429 | if (retval == 0) { |
e6456186 | 430 | u32 save = spi->mode; |
814a8d50 AP |
431 | |
432 | if (tmp & ~SPI_MODE_MASK) { | |
433 | retval = -EINVAL; | |
434 | break; | |
435 | } | |
436 | ||
437 | tmp |= spi->mode & ~SPI_MODE_MASK; | |
dc64d39b | 438 | spi->mode = (u16)tmp; |
814a8d50 AP |
439 | retval = spi_setup(spi); |
440 | if (retval < 0) | |
441 | spi->mode = save; | |
442 | else | |
dc64d39b | 443 | dev_dbg(&spi->dev, "spi mode %x\n", tmp); |
814a8d50 AP |
444 | } |
445 | break; | |
446 | case SPI_IOC_WR_LSB_FIRST: | |
447 | retval = __get_user(tmp, (__u8 __user *)arg); | |
448 | if (retval == 0) { | |
e6456186 | 449 | u32 save = spi->mode; |
814a8d50 AP |
450 | |
451 | if (tmp) | |
452 | spi->mode |= SPI_LSB_FIRST; | |
453 | else | |
454 | spi->mode &= ~SPI_LSB_FIRST; | |
455 | retval = spi_setup(spi); | |
456 | if (retval < 0) | |
457 | spi->mode = save; | |
458 | else | |
459 | dev_dbg(&spi->dev, "%csb first\n", | |
460 | tmp ? 'l' : 'm'); | |
461 | } | |
462 | break; | |
463 | case SPI_IOC_WR_BITS_PER_WORD: | |
464 | retval = __get_user(tmp, (__u8 __user *)arg); | |
465 | if (retval == 0) { | |
466 | u8 save = spi->bits_per_word; | |
467 | ||
468 | spi->bits_per_word = tmp; | |
469 | retval = spi_setup(spi); | |
470 | if (retval < 0) | |
471 | spi->bits_per_word = save; | |
472 | else | |
473 | dev_dbg(&spi->dev, "%d bits per word\n", tmp); | |
474 | } | |
475 | break; | |
476 | case SPI_IOC_WR_MAX_SPEED_HZ: | |
477 | retval = __get_user(tmp, (__u32 __user *)arg); | |
478 | if (retval == 0) { | |
479 | u32 save = spi->max_speed_hz; | |
480 | ||
481 | spi->max_speed_hz = tmp; | |
482 | retval = spi_setup(spi); | |
91690516 MB |
483 | if (retval >= 0) |
484 | spidev->speed_hz = tmp; | |
814a8d50 AP |
485 | else |
486 | dev_dbg(&spi->dev, "%d Hz (max)\n", tmp); | |
91690516 | 487 | spi->max_speed_hz = save; |
814a8d50 AP |
488 | } |
489 | break; | |
490 | ||
491 | default: | |
492 | /* segmented and/or full-duplex I/O request */ | |
7782a1a9 IA |
493 | /* Check message and copy into scratch area */ |
494 | ioc = spidev_get_ioc_message(cmd, | |
495 | (struct spi_ioc_transfer __user *)arg, &n_ioc); | |
496 | if (IS_ERR(ioc)) { | |
497 | retval = PTR_ERR(ioc); | |
814a8d50 AP |
498 | break; |
499 | } | |
7782a1a9 IA |
500 | if (!ioc) |
501 | break; /* n_ioc is also 0 */ | |
814a8d50 AP |
502 | |
503 | /* translate to spi_message, execute */ | |
504 | retval = spidev_message(spidev, ioc, n_ioc); | |
505 | kfree(ioc); | |
506 | break; | |
507 | } | |
4ef754b7 AC |
508 | |
509 | mutex_unlock(&spidev->buf_lock); | |
25d5cb4b | 510 | spi_dev_put(spi); |
814a8d50 AP |
511 | return retval; |
512 | } | |
513 | ||
7d48ec36 | 514 | #ifdef CONFIG_COMPAT |
7782a1a9 IA |
515 | static long |
516 | spidev_compat_ioc_message(struct file *filp, unsigned int cmd, | |
517 | unsigned long arg) | |
518 | { | |
519 | struct spi_ioc_transfer __user *u_ioc; | |
520 | int retval = 0; | |
521 | struct spidev_data *spidev; | |
522 | struct spi_device *spi; | |
523 | unsigned n_ioc, n; | |
524 | struct spi_ioc_transfer *ioc; | |
525 | ||
526 | u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg); | |
527 | if (!access_ok(VERIFY_READ, u_ioc, _IOC_SIZE(cmd))) | |
528 | return -EFAULT; | |
529 | ||
530 | /* guard against device removal before, or while, | |
531 | * we issue this ioctl. | |
532 | */ | |
533 | spidev = filp->private_data; | |
534 | spin_lock_irq(&spidev->spi_lock); | |
535 | spi = spi_dev_get(spidev->spi); | |
536 | spin_unlock_irq(&spidev->spi_lock); | |
537 | ||
538 | if (spi == NULL) | |
539 | return -ESHUTDOWN; | |
540 | ||
541 | /* SPI_IOC_MESSAGE needs the buffer locked "normally" */ | |
542 | mutex_lock(&spidev->buf_lock); | |
543 | ||
544 | /* Check message and copy into scratch area */ | |
545 | ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc); | |
546 | if (IS_ERR(ioc)) { | |
547 | retval = PTR_ERR(ioc); | |
548 | goto done; | |
549 | } | |
550 | if (!ioc) | |
551 | goto done; /* n_ioc is also 0 */ | |
552 | ||
553 | /* Convert buffer pointers */ | |
554 | for (n = 0; n < n_ioc; n++) { | |
555 | ioc[n].rx_buf = (uintptr_t) compat_ptr(ioc[n].rx_buf); | |
556 | ioc[n].tx_buf = (uintptr_t) compat_ptr(ioc[n].tx_buf); | |
557 | } | |
558 | ||
559 | /* translate to spi_message, execute */ | |
560 | retval = spidev_message(spidev, ioc, n_ioc); | |
561 | kfree(ioc); | |
562 | ||
563 | done: | |
564 | mutex_unlock(&spidev->buf_lock); | |
565 | spi_dev_put(spi); | |
566 | return retval; | |
567 | } | |
568 | ||
7d48ec36 BW |
569 | static long |
570 | spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
571 | { | |
7782a1a9 IA |
572 | if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC |
573 | && _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0)) | |
574 | && _IOC_DIR(cmd) == _IOC_WRITE) | |
575 | return spidev_compat_ioc_message(filp, cmd, arg); | |
576 | ||
7d48ec36 BW |
577 | return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); |
578 | } | |
579 | #else | |
580 | #define spidev_compat_ioctl NULL | |
581 | #endif /* CONFIG_COMPAT */ | |
582 | ||
814a8d50 AP |
583 | static int spidev_open(struct inode *inode, struct file *filp) |
584 | { | |
585 | struct spidev_data *spidev; | |
586 | int status = -ENXIO; | |
587 | ||
588 | mutex_lock(&device_list_lock); | |
589 | ||
590 | list_for_each_entry(spidev, &device_list, device_entry) { | |
b2c8dadd | 591 | if (spidev->devt == inode->i_rdev) { |
814a8d50 AP |
592 | status = 0; |
593 | break; | |
594 | } | |
595 | } | |
865f6d19 RJ |
596 | |
597 | if (status) { | |
598 | pr_debug("spidev: nothing for minor %d\n", iminor(inode)); | |
599 | goto err_find_dev; | |
600 | } | |
601 | ||
602 | if (!spidev->tx_buffer) { | |
603 | spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL); | |
604 | if (!spidev->tx_buffer) { | |
89a63566 CIK |
605 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); |
606 | status = -ENOMEM; | |
865f6d19 | 607 | goto err_find_dev; |
814a8d50 | 608 | } |
89a63566 | 609 | } |
865f6d19 RJ |
610 | |
611 | if (!spidev->rx_buffer) { | |
612 | spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL); | |
613 | if (!spidev->rx_buffer) { | |
614 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); | |
615 | status = -ENOMEM; | |
616 | goto err_alloc_rx_buf; | |
814a8d50 | 617 | } |
865f6d19 RJ |
618 | } |
619 | ||
620 | spidev->users++; | |
621 | filp->private_data = spidev; | |
622 | nonseekable_open(inode, filp); | |
814a8d50 | 623 | |
865f6d19 RJ |
624 | mutex_unlock(&device_list_lock); |
625 | return 0; | |
626 | ||
627 | err_alloc_rx_buf: | |
628 | kfree(spidev->tx_buffer); | |
629 | spidev->tx_buffer = NULL; | |
630 | err_find_dev: | |
814a8d50 AP |
631 | mutex_unlock(&device_list_lock); |
632 | return status; | |
633 | } | |
634 | ||
635 | static int spidev_release(struct inode *inode, struct file *filp) | |
636 | { | |
637 | struct spidev_data *spidev; | |
814a8d50 AP |
638 | |
639 | mutex_lock(&device_list_lock); | |
640 | spidev = filp->private_data; | |
641 | filp->private_data = NULL; | |
b2c8dadd DB |
642 | |
643 | /* last close? */ | |
814a8d50 AP |
644 | spidev->users--; |
645 | if (!spidev->users) { | |
b2c8dadd DB |
646 | int dofree; |
647 | ||
865f6d19 RJ |
648 | kfree(spidev->tx_buffer); |
649 | spidev->tx_buffer = NULL; | |
650 | ||
651 | kfree(spidev->rx_buffer); | |
652 | spidev->rx_buffer = NULL; | |
b2c8dadd | 653 | |
dd85ebf6 SM |
654 | if (spidev->spi) |
655 | spidev->speed_hz = spidev->spi->max_speed_hz; | |
91690516 | 656 | |
b2c8dadd DB |
657 | /* ... after we unbound from the underlying device? */ |
658 | spin_lock_irq(&spidev->spi_lock); | |
659 | dofree = (spidev->spi == NULL); | |
660 | spin_unlock_irq(&spidev->spi_lock); | |
661 | ||
662 | if (dofree) | |
663 | kfree(spidev); | |
814a8d50 AP |
664 | } |
665 | mutex_unlock(&device_list_lock); | |
666 | ||
99472cc0 | 667 | return 0; |
814a8d50 AP |
668 | } |
669 | ||
828c0950 | 670 | static const struct file_operations spidev_fops = { |
814a8d50 AP |
671 | .owner = THIS_MODULE, |
672 | /* REVISIT switch to aio primitives, so that userspace | |
673 | * gets more complete API coverage. It'll simplify things | |
674 | * too, except for the locking. | |
675 | */ | |
676 | .write = spidev_write, | |
677 | .read = spidev_read, | |
4ef754b7 | 678 | .unlocked_ioctl = spidev_ioctl, |
7d48ec36 | 679 | .compat_ioctl = spidev_compat_ioctl, |
814a8d50 AP |
680 | .open = spidev_open, |
681 | .release = spidev_release, | |
6038f373 | 682 | .llseek = no_llseek, |
814a8d50 AP |
683 | }; |
684 | ||
685 | /*-------------------------------------------------------------------------*/ | |
686 | ||
687 | /* The main reason to have this class is to make mdev/udev create the | |
688 | * /dev/spidevB.C character device nodes exposing our userspace API. | |
689 | * It also simplifies memory management. | |
690 | */ | |
691 | ||
b2c8dadd | 692 | static struct class *spidev_class; |
814a8d50 | 693 | |
956b200a MB |
694 | #ifdef CONFIG_OF |
695 | static const struct of_device_id spidev_dt_ids[] = { | |
696 | { .compatible = "rohm,dh2228fv" }, | |
6fec919b | 697 | { .compatible = "lineartechnology,ltc2488" }, |
956b200a MB |
698 | {}, |
699 | }; | |
700 | MODULE_DEVICE_TABLE(of, spidev_dt_ids); | |
701 | #endif | |
702 | ||
814a8d50 AP |
703 | /*-------------------------------------------------------------------------*/ |
704 | ||
fd4a319b | 705 | static int spidev_probe(struct spi_device *spi) |
814a8d50 AP |
706 | { |
707 | struct spidev_data *spidev; | |
708 | int status; | |
709 | unsigned long minor; | |
710 | ||
956b200a MB |
711 | /* |
712 | * spidev should never be referenced in DT without a specific | |
ffe22888 | 713 | * compatible string, it is a Linux implementation thing |
956b200a MB |
714 | * rather than a description of the hardware. |
715 | */ | |
716 | if (spi->dev.of_node && !of_match_device(spidev_dt_ids, &spi->dev)) { | |
717 | dev_err(&spi->dev, "buggy DT: spidev listed directly in DT\n"); | |
718 | WARN_ON(spi->dev.of_node && | |
719 | !of_match_device(spidev_dt_ids, &spi->dev)); | |
720 | } | |
721 | ||
814a8d50 AP |
722 | /* Allocate driver data */ |
723 | spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); | |
724 | if (!spidev) | |
725 | return -ENOMEM; | |
726 | ||
727 | /* Initialize the driver data */ | |
728 | spidev->spi = spi; | |
25d5cb4b | 729 | spin_lock_init(&spidev->spi_lock); |
814a8d50 AP |
730 | mutex_init(&spidev->buf_lock); |
731 | ||
732 | INIT_LIST_HEAD(&spidev->device_entry); | |
733 | ||
734 | /* If we can allocate a minor number, hook up this device. | |
735 | * Reusing minors is fine so long as udev or mdev is working. | |
736 | */ | |
737 | mutex_lock(&device_list_lock); | |
0a4dd778 | 738 | minor = find_first_zero_bit(minors, N_SPI_MINORS); |
814a8d50 | 739 | if (minor < N_SPI_MINORS) { |
b2c8dadd DB |
740 | struct device *dev; |
741 | ||
742 | spidev->devt = MKDEV(SPIDEV_MAJOR, minor); | |
a9b12619 GKH |
743 | dev = device_create(spidev_class, &spi->dev, spidev->devt, |
744 | spidev, "spidev%d.%d", | |
745 | spi->master->bus_num, spi->chip_select); | |
8c6ffba0 | 746 | status = PTR_ERR_OR_ZERO(dev); |
814a8d50 AP |
747 | } else { |
748 | dev_dbg(&spi->dev, "no minor number available!\n"); | |
749 | status = -ENODEV; | |
750 | } | |
751 | if (status == 0) { | |
752 | set_bit(minor, minors); | |
814a8d50 AP |
753 | list_add(&spidev->device_entry, &device_list); |
754 | } | |
755 | mutex_unlock(&device_list_lock); | |
756 | ||
91690516 MB |
757 | spidev->speed_hz = spi->max_speed_hz; |
758 | ||
aaacf4bb WO |
759 | if (status == 0) |
760 | spi_set_drvdata(spi, spidev); | |
761 | else | |
814a8d50 AP |
762 | kfree(spidev); |
763 | ||
764 | return status; | |
765 | } | |
766 | ||
fd4a319b | 767 | static int spidev_remove(struct spi_device *spi) |
814a8d50 | 768 | { |
b2c8dadd | 769 | struct spidev_data *spidev = spi_get_drvdata(spi); |
814a8d50 | 770 | |
25d5cb4b DB |
771 | /* make sure ops on existing fds can abort cleanly */ |
772 | spin_lock_irq(&spidev->spi_lock); | |
773 | spidev->spi = NULL; | |
774 | spin_unlock_irq(&spidev->spi_lock); | |
814a8d50 | 775 | |
25d5cb4b DB |
776 | /* prevent new opens */ |
777 | mutex_lock(&device_list_lock); | |
814a8d50 | 778 | list_del(&spidev->device_entry); |
b2c8dadd DB |
779 | device_destroy(spidev_class, spidev->devt); |
780 | clear_bit(MINOR(spidev->devt), minors); | |
781 | if (spidev->users == 0) | |
782 | kfree(spidev); | |
814a8d50 AP |
783 | mutex_unlock(&device_list_lock); |
784 | ||
785 | return 0; | |
786 | } | |
787 | ||
db389b61 | 788 | static struct spi_driver spidev_spi_driver = { |
814a8d50 AP |
789 | .driver = { |
790 | .name = "spidev", | |
880cfd43 | 791 | .of_match_table = of_match_ptr(spidev_dt_ids), |
814a8d50 AP |
792 | }, |
793 | .probe = spidev_probe, | |
fd4a319b | 794 | .remove = spidev_remove, |
814a8d50 AP |
795 | |
796 | /* NOTE: suspend/resume methods are not necessary here. | |
797 | * We don't do anything except pass the requests to/from | |
798 | * the underlying controller. The refrigerator handles | |
799 | * most issues; the controller driver handles the rest. | |
800 | */ | |
801 | }; | |
802 | ||
803 | /*-------------------------------------------------------------------------*/ | |
804 | ||
805 | static int __init spidev_init(void) | |
806 | { | |
807 | int status; | |
808 | ||
809 | /* Claim our 256 reserved device numbers. Then register a class | |
810 | * that will key udev/mdev to add/remove /dev nodes. Last, register | |
811 | * the driver which manages those device numbers. | |
812 | */ | |
813 | BUILD_BUG_ON(N_SPI_MINORS > 256); | |
814 | status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); | |
815 | if (status < 0) | |
816 | return status; | |
817 | ||
b2c8dadd DB |
818 | spidev_class = class_create(THIS_MODULE, "spidev"); |
819 | if (IS_ERR(spidev_class)) { | |
db389b61 | 820 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
b2c8dadd | 821 | return PTR_ERR(spidev_class); |
814a8d50 AP |
822 | } |
823 | ||
db389b61 | 824 | status = spi_register_driver(&spidev_spi_driver); |
814a8d50 | 825 | if (status < 0) { |
b2c8dadd | 826 | class_destroy(spidev_class); |
db389b61 | 827 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
828 | } |
829 | return status; | |
830 | } | |
831 | module_init(spidev_init); | |
832 | ||
833 | static void __exit spidev_exit(void) | |
834 | { | |
db389b61 | 835 | spi_unregister_driver(&spidev_spi_driver); |
b2c8dadd | 836 | class_destroy(spidev_class); |
db389b61 | 837 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
838 | } |
839 | module_exit(spidev_exit); | |
840 | ||
841 | MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); | |
842 | MODULE_DESCRIPTION("User mode SPI device interface"); | |
843 | MODULE_LICENSE("GPL"); | |
e0626e38 | 844 | MODULE_ALIAS("spi:spidev"); |