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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 | /* |
99 | * We can't use the standard synchronous wrappers for file I/O; we | |
100 | * need to protect against async removal of the underlying spi_device. | |
101 | */ | |
102 | static void spidev_complete(void *arg) | |
103 | { | |
104 | complete(arg); | |
105 | } | |
106 | ||
107 | static ssize_t | |
108 | spidev_sync(struct spidev_data *spidev, struct spi_message *message) | |
109 | { | |
110 | DECLARE_COMPLETION_ONSTACK(done); | |
111 | int status; | |
112 | ||
113 | message->complete = spidev_complete; | |
114 | message->context = &done; | |
115 | ||
116 | spin_lock_irq(&spidev->spi_lock); | |
117 | if (spidev->spi == NULL) | |
118 | status = -ESHUTDOWN; | |
119 | else | |
120 | status = spi_async(spidev->spi, message); | |
121 | spin_unlock_irq(&spidev->spi_lock); | |
122 | ||
123 | if (status == 0) { | |
124 | wait_for_completion(&done); | |
125 | status = message->status; | |
126 | if (status == 0) | |
127 | status = message->actual_length; | |
128 | } | |
129 | return status; | |
130 | } | |
131 | ||
132 | static inline ssize_t | |
133 | spidev_sync_write(struct spidev_data *spidev, size_t len) | |
134 | { | |
135 | struct spi_transfer t = { | |
865f6d19 | 136 | .tx_buf = spidev->tx_buffer, |
25d5cb4b | 137 | .len = len, |
91690516 | 138 | .speed_hz = spidev->speed_hz, |
25d5cb4b DB |
139 | }; |
140 | struct spi_message m; | |
141 | ||
142 | spi_message_init(&m); | |
143 | spi_message_add_tail(&t, &m); | |
144 | return spidev_sync(spidev, &m); | |
145 | } | |
146 | ||
147 | static inline ssize_t | |
148 | spidev_sync_read(struct spidev_data *spidev, size_t len) | |
149 | { | |
150 | struct spi_transfer t = { | |
865f6d19 | 151 | .rx_buf = spidev->rx_buffer, |
25d5cb4b | 152 | .len = len, |
91690516 | 153 | .speed_hz = spidev->speed_hz, |
25d5cb4b DB |
154 | }; |
155 | struct spi_message m; | |
156 | ||
157 | spi_message_init(&m); | |
158 | spi_message_add_tail(&t, &m); | |
159 | return spidev_sync(spidev, &m); | |
160 | } | |
161 | ||
162 | /*-------------------------------------------------------------------------*/ | |
163 | ||
814a8d50 AP |
164 | /* Read-only message with current device setup */ |
165 | static ssize_t | |
166 | spidev_read(struct file *filp, char __user *buf, size_t count, loff_t *f_pos) | |
167 | { | |
168 | struct spidev_data *spidev; | |
814a8d50 AP |
169 | ssize_t status = 0; |
170 | ||
171 | /* chipselect only toggles at start or end of operation */ | |
172 | if (count > bufsiz) | |
173 | return -EMSGSIZE; | |
174 | ||
175 | spidev = filp->private_data; | |
814a8d50 AP |
176 | |
177 | mutex_lock(&spidev->buf_lock); | |
25d5cb4b | 178 | status = spidev_sync_read(spidev, count); |
4b1295b0 | 179 | if (status > 0) { |
814a8d50 AP |
180 | unsigned long missing; |
181 | ||
865f6d19 | 182 | missing = copy_to_user(buf, spidev->rx_buffer, status); |
4b1295b0 | 183 | if (missing == status) |
814a8d50 AP |
184 | status = -EFAULT; |
185 | else | |
4b1295b0 | 186 | status = status - missing; |
814a8d50 AP |
187 | } |
188 | mutex_unlock(&spidev->buf_lock); | |
189 | ||
190 | return status; | |
191 | } | |
192 | ||
193 | /* Write-only message with current device setup */ | |
194 | static ssize_t | |
195 | spidev_write(struct file *filp, const char __user *buf, | |
196 | size_t count, loff_t *f_pos) | |
197 | { | |
198 | struct spidev_data *spidev; | |
814a8d50 AP |
199 | ssize_t status = 0; |
200 | unsigned long missing; | |
201 | ||
202 | /* chipselect only toggles at start or end of operation */ | |
203 | if (count > bufsiz) | |
204 | return -EMSGSIZE; | |
205 | ||
206 | spidev = filp->private_data; | |
814a8d50 AP |
207 | |
208 | mutex_lock(&spidev->buf_lock); | |
865f6d19 | 209 | missing = copy_from_user(spidev->tx_buffer, buf, count); |
95c63cfb | 210 | if (missing == 0) |
25d5cb4b | 211 | status = spidev_sync_write(spidev, count); |
95c63cfb | 212 | else |
814a8d50 AP |
213 | status = -EFAULT; |
214 | mutex_unlock(&spidev->buf_lock); | |
215 | ||
216 | return status; | |
217 | } | |
218 | ||
219 | static int spidev_message(struct spidev_data *spidev, | |
220 | struct spi_ioc_transfer *u_xfers, unsigned n_xfers) | |
221 | { | |
222 | struct spi_message msg; | |
223 | struct spi_transfer *k_xfers; | |
224 | struct spi_transfer *k_tmp; | |
225 | struct spi_ioc_transfer *u_tmp; | |
814a8d50 | 226 | unsigned n, total; |
865f6d19 | 227 | u8 *tx_buf, *rx_buf; |
814a8d50 AP |
228 | int status = -EFAULT; |
229 | ||
230 | spi_message_init(&msg); | |
231 | k_xfers = kcalloc(n_xfers, sizeof(*k_tmp), GFP_KERNEL); | |
232 | if (k_xfers == NULL) | |
233 | return -ENOMEM; | |
234 | ||
235 | /* Construct spi_message, copying any tx data to bounce buffer. | |
236 | * We walk the array of user-provided transfers, using each one | |
237 | * to initialize a kernel version of the same transfer. | |
238 | */ | |
865f6d19 RJ |
239 | tx_buf = spidev->tx_buffer; |
240 | rx_buf = spidev->rx_buffer; | |
814a8d50 AP |
241 | total = 0; |
242 | for (n = n_xfers, k_tmp = k_xfers, u_tmp = u_xfers; | |
243 | n; | |
244 | n--, k_tmp++, u_tmp++) { | |
245 | k_tmp->len = u_tmp->len; | |
246 | ||
da90fa8f DP |
247 | total += k_tmp->len; |
248 | if (total > bufsiz) { | |
249 | status = -EMSGSIZE; | |
250 | goto done; | |
251 | } | |
252 | ||
814a8d50 | 253 | if (u_tmp->rx_buf) { |
865f6d19 | 254 | k_tmp->rx_buf = rx_buf; |
96ddbf50 | 255 | if (!access_ok(VERIFY_WRITE, (u8 __user *) |
142956af | 256 | (uintptr_t) u_tmp->rx_buf, |
96ddbf50 | 257 | u_tmp->len)) |
814a8d50 AP |
258 | goto done; |
259 | } | |
260 | if (u_tmp->tx_buf) { | |
865f6d19 RJ |
261 | k_tmp->tx_buf = tx_buf; |
262 | if (copy_from_user(tx_buf, (const u8 __user *) | |
142956af | 263 | (uintptr_t) u_tmp->tx_buf, |
814a8d50 AP |
264 | u_tmp->len)) |
265 | goto done; | |
266 | } | |
865f6d19 RJ |
267 | tx_buf += k_tmp->len; |
268 | rx_buf += k_tmp->len; | |
814a8d50 AP |
269 | |
270 | k_tmp->cs_change = !!u_tmp->cs_change; | |
dc64d39b GU |
271 | k_tmp->tx_nbits = u_tmp->tx_nbits; |
272 | k_tmp->rx_nbits = u_tmp->rx_nbits; | |
814a8d50 AP |
273 | k_tmp->bits_per_word = u_tmp->bits_per_word; |
274 | k_tmp->delay_usecs = u_tmp->delay_usecs; | |
275 | k_tmp->speed_hz = u_tmp->speed_hz; | |
91690516 MB |
276 | if (!k_tmp->speed_hz) |
277 | k_tmp->speed_hz = spidev->speed_hz; | |
814a8d50 | 278 | #ifdef VERBOSE |
41df70d9 | 279 | dev_dbg(&spidev->spi->dev, |
814a8d50 AP |
280 | " xfer len %zd %s%s%s%dbits %u usec %uHz\n", |
281 | u_tmp->len, | |
282 | u_tmp->rx_buf ? "rx " : "", | |
283 | u_tmp->tx_buf ? "tx " : "", | |
284 | u_tmp->cs_change ? "cs " : "", | |
41df70d9 | 285 | u_tmp->bits_per_word ? : spidev->spi->bits_per_word, |
814a8d50 | 286 | u_tmp->delay_usecs, |
41df70d9 | 287 | u_tmp->speed_hz ? : spidev->spi->max_speed_hz); |
814a8d50 AP |
288 | #endif |
289 | spi_message_add_tail(k_tmp, &msg); | |
290 | } | |
291 | ||
25d5cb4b | 292 | status = spidev_sync(spidev, &msg); |
814a8d50 AP |
293 | if (status < 0) |
294 | goto done; | |
295 | ||
296 | /* copy any rx data out of bounce buffer */ | |
865f6d19 | 297 | rx_buf = spidev->rx_buffer; |
814a8d50 AP |
298 | for (n = n_xfers, u_tmp = u_xfers; n; n--, u_tmp++) { |
299 | if (u_tmp->rx_buf) { | |
4917d927 | 300 | if (__copy_to_user((u8 __user *) |
865f6d19 | 301 | (uintptr_t) u_tmp->rx_buf, rx_buf, |
814a8d50 AP |
302 | u_tmp->len)) { |
303 | status = -EFAULT; | |
304 | goto done; | |
305 | } | |
306 | } | |
865f6d19 | 307 | rx_buf += u_tmp->len; |
814a8d50 AP |
308 | } |
309 | status = total; | |
310 | ||
311 | done: | |
814a8d50 AP |
312 | kfree(k_xfers); |
313 | return status; | |
314 | } | |
315 | ||
7782a1a9 IA |
316 | static struct spi_ioc_transfer * |
317 | spidev_get_ioc_message(unsigned int cmd, struct spi_ioc_transfer __user *u_ioc, | |
318 | unsigned *n_ioc) | |
319 | { | |
320 | struct spi_ioc_transfer *ioc; | |
321 | u32 tmp; | |
322 | ||
323 | /* Check type, command number and direction */ | |
324 | if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC | |
325 | || _IOC_NR(cmd) != _IOC_NR(SPI_IOC_MESSAGE(0)) | |
326 | || _IOC_DIR(cmd) != _IOC_WRITE) | |
327 | return ERR_PTR(-ENOTTY); | |
328 | ||
329 | tmp = _IOC_SIZE(cmd); | |
330 | if ((tmp % sizeof(struct spi_ioc_transfer)) != 0) | |
331 | return ERR_PTR(-EINVAL); | |
332 | *n_ioc = tmp / sizeof(struct spi_ioc_transfer); | |
333 | if (*n_ioc == 0) | |
334 | return NULL; | |
335 | ||
336 | /* copy into scratch area */ | |
337 | ioc = kmalloc(tmp, GFP_KERNEL); | |
338 | if (!ioc) | |
339 | return ERR_PTR(-ENOMEM); | |
340 | if (__copy_from_user(ioc, u_ioc, tmp)) { | |
341 | kfree(ioc); | |
342 | return ERR_PTR(-EFAULT); | |
343 | } | |
344 | return ioc; | |
345 | } | |
346 | ||
4ef754b7 AC |
347 | static long |
348 | spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
814a8d50 AP |
349 | { |
350 | int err = 0; | |
351 | int retval = 0; | |
352 | struct spidev_data *spidev; | |
353 | struct spi_device *spi; | |
354 | u32 tmp; | |
355 | unsigned n_ioc; | |
356 | struct spi_ioc_transfer *ioc; | |
357 | ||
358 | /* Check type and command number */ | |
359 | if (_IOC_TYPE(cmd) != SPI_IOC_MAGIC) | |
360 | return -ENOTTY; | |
361 | ||
362 | /* Check access direction once here; don't repeat below. | |
363 | * IOC_DIR is from the user perspective, while access_ok is | |
364 | * from the kernel perspective; so they look reversed. | |
365 | */ | |
366 | if (_IOC_DIR(cmd) & _IOC_READ) | |
367 | err = !access_ok(VERIFY_WRITE, | |
368 | (void __user *)arg, _IOC_SIZE(cmd)); | |
369 | if (err == 0 && _IOC_DIR(cmd) & _IOC_WRITE) | |
370 | err = !access_ok(VERIFY_READ, | |
371 | (void __user *)arg, _IOC_SIZE(cmd)); | |
372 | if (err) | |
373 | return -EFAULT; | |
374 | ||
25d5cb4b DB |
375 | /* guard against device removal before, or while, |
376 | * we issue this ioctl. | |
377 | */ | |
814a8d50 | 378 | spidev = filp->private_data; |
25d5cb4b DB |
379 | spin_lock_irq(&spidev->spi_lock); |
380 | spi = spi_dev_get(spidev->spi); | |
381 | spin_unlock_irq(&spidev->spi_lock); | |
382 | ||
383 | if (spi == NULL) | |
384 | return -ESHUTDOWN; | |
814a8d50 | 385 | |
4ef754b7 AC |
386 | /* use the buffer lock here for triple duty: |
387 | * - prevent I/O (from us) so calling spi_setup() is safe; | |
388 | * - prevent concurrent SPI_IOC_WR_* from morphing | |
389 | * data fields while SPI_IOC_RD_* reads them; | |
390 | * - SPI_IOC_MESSAGE needs the buffer locked "normally". | |
391 | */ | |
392 | mutex_lock(&spidev->buf_lock); | |
393 | ||
814a8d50 AP |
394 | switch (cmd) { |
395 | /* read requests */ | |
396 | case SPI_IOC_RD_MODE: | |
397 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
398 | (__u8 __user *)arg); | |
399 | break; | |
dc64d39b GU |
400 | case SPI_IOC_RD_MODE32: |
401 | retval = __put_user(spi->mode & SPI_MODE_MASK, | |
402 | (__u32 __user *)arg); | |
403 | break; | |
814a8d50 AP |
404 | case SPI_IOC_RD_LSB_FIRST: |
405 | retval = __put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0, | |
406 | (__u8 __user *)arg); | |
407 | break; | |
408 | case SPI_IOC_RD_BITS_PER_WORD: | |
409 | retval = __put_user(spi->bits_per_word, (__u8 __user *)arg); | |
410 | break; | |
411 | case SPI_IOC_RD_MAX_SPEED_HZ: | |
91690516 | 412 | retval = __put_user(spidev->speed_hz, (__u32 __user *)arg); |
814a8d50 AP |
413 | break; |
414 | ||
415 | /* write requests */ | |
416 | case SPI_IOC_WR_MODE: | |
dc64d39b GU |
417 | case SPI_IOC_WR_MODE32: |
418 | if (cmd == SPI_IOC_WR_MODE) | |
419 | retval = __get_user(tmp, (u8 __user *)arg); | |
420 | else | |
421 | retval = __get_user(tmp, (u32 __user *)arg); | |
814a8d50 | 422 | if (retval == 0) { |
e6456186 | 423 | u32 save = spi->mode; |
814a8d50 AP |
424 | |
425 | if (tmp & ~SPI_MODE_MASK) { | |
426 | retval = -EINVAL; | |
427 | break; | |
428 | } | |
429 | ||
430 | tmp |= spi->mode & ~SPI_MODE_MASK; | |
dc64d39b | 431 | spi->mode = (u16)tmp; |
814a8d50 AP |
432 | retval = spi_setup(spi); |
433 | if (retval < 0) | |
434 | spi->mode = save; | |
435 | else | |
dc64d39b | 436 | dev_dbg(&spi->dev, "spi mode %x\n", tmp); |
814a8d50 AP |
437 | } |
438 | break; | |
439 | case SPI_IOC_WR_LSB_FIRST: | |
440 | retval = __get_user(tmp, (__u8 __user *)arg); | |
441 | if (retval == 0) { | |
e6456186 | 442 | u32 save = spi->mode; |
814a8d50 AP |
443 | |
444 | if (tmp) | |
445 | spi->mode |= SPI_LSB_FIRST; | |
446 | else | |
447 | spi->mode &= ~SPI_LSB_FIRST; | |
448 | retval = spi_setup(spi); | |
449 | if (retval < 0) | |
450 | spi->mode = save; | |
451 | else | |
452 | dev_dbg(&spi->dev, "%csb first\n", | |
453 | tmp ? 'l' : 'm'); | |
454 | } | |
455 | break; | |
456 | case SPI_IOC_WR_BITS_PER_WORD: | |
457 | retval = __get_user(tmp, (__u8 __user *)arg); | |
458 | if (retval == 0) { | |
459 | u8 save = spi->bits_per_word; | |
460 | ||
461 | spi->bits_per_word = tmp; | |
462 | retval = spi_setup(spi); | |
463 | if (retval < 0) | |
464 | spi->bits_per_word = save; | |
465 | else | |
466 | dev_dbg(&spi->dev, "%d bits per word\n", tmp); | |
467 | } | |
468 | break; | |
469 | case SPI_IOC_WR_MAX_SPEED_HZ: | |
470 | retval = __get_user(tmp, (__u32 __user *)arg); | |
471 | if (retval == 0) { | |
472 | u32 save = spi->max_speed_hz; | |
473 | ||
474 | spi->max_speed_hz = tmp; | |
475 | retval = spi_setup(spi); | |
91690516 MB |
476 | if (retval >= 0) |
477 | spidev->speed_hz = tmp; | |
814a8d50 AP |
478 | else |
479 | dev_dbg(&spi->dev, "%d Hz (max)\n", tmp); | |
91690516 | 480 | spi->max_speed_hz = save; |
814a8d50 AP |
481 | } |
482 | break; | |
483 | ||
484 | default: | |
485 | /* segmented and/or full-duplex I/O request */ | |
7782a1a9 IA |
486 | /* Check message and copy into scratch area */ |
487 | ioc = spidev_get_ioc_message(cmd, | |
488 | (struct spi_ioc_transfer __user *)arg, &n_ioc); | |
489 | if (IS_ERR(ioc)) { | |
490 | retval = PTR_ERR(ioc); | |
814a8d50 AP |
491 | break; |
492 | } | |
7782a1a9 IA |
493 | if (!ioc) |
494 | break; /* n_ioc is also 0 */ | |
814a8d50 AP |
495 | |
496 | /* translate to spi_message, execute */ | |
497 | retval = spidev_message(spidev, ioc, n_ioc); | |
498 | kfree(ioc); | |
499 | break; | |
500 | } | |
4ef754b7 AC |
501 | |
502 | mutex_unlock(&spidev->buf_lock); | |
25d5cb4b | 503 | spi_dev_put(spi); |
814a8d50 AP |
504 | return retval; |
505 | } | |
506 | ||
7d48ec36 | 507 | #ifdef CONFIG_COMPAT |
7782a1a9 IA |
508 | static long |
509 | spidev_compat_ioc_message(struct file *filp, unsigned int cmd, | |
510 | unsigned long arg) | |
511 | { | |
512 | struct spi_ioc_transfer __user *u_ioc; | |
513 | int retval = 0; | |
514 | struct spidev_data *spidev; | |
515 | struct spi_device *spi; | |
516 | unsigned n_ioc, n; | |
517 | struct spi_ioc_transfer *ioc; | |
518 | ||
519 | u_ioc = (struct spi_ioc_transfer __user *) compat_ptr(arg); | |
520 | if (!access_ok(VERIFY_READ, u_ioc, _IOC_SIZE(cmd))) | |
521 | return -EFAULT; | |
522 | ||
523 | /* guard against device removal before, or while, | |
524 | * we issue this ioctl. | |
525 | */ | |
526 | spidev = filp->private_data; | |
527 | spin_lock_irq(&spidev->spi_lock); | |
528 | spi = spi_dev_get(spidev->spi); | |
529 | spin_unlock_irq(&spidev->spi_lock); | |
530 | ||
531 | if (spi == NULL) | |
532 | return -ESHUTDOWN; | |
533 | ||
534 | /* SPI_IOC_MESSAGE needs the buffer locked "normally" */ | |
535 | mutex_lock(&spidev->buf_lock); | |
536 | ||
537 | /* Check message and copy into scratch area */ | |
538 | ioc = spidev_get_ioc_message(cmd, u_ioc, &n_ioc); | |
539 | if (IS_ERR(ioc)) { | |
540 | retval = PTR_ERR(ioc); | |
541 | goto done; | |
542 | } | |
543 | if (!ioc) | |
544 | goto done; /* n_ioc is also 0 */ | |
545 | ||
546 | /* Convert buffer pointers */ | |
547 | for (n = 0; n < n_ioc; n++) { | |
548 | ioc[n].rx_buf = (uintptr_t) compat_ptr(ioc[n].rx_buf); | |
549 | ioc[n].tx_buf = (uintptr_t) compat_ptr(ioc[n].tx_buf); | |
550 | } | |
551 | ||
552 | /* translate to spi_message, execute */ | |
553 | retval = spidev_message(spidev, ioc, n_ioc); | |
554 | kfree(ioc); | |
555 | ||
556 | done: | |
557 | mutex_unlock(&spidev->buf_lock); | |
558 | spi_dev_put(spi); | |
559 | return retval; | |
560 | } | |
561 | ||
7d48ec36 BW |
562 | static long |
563 | spidev_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
564 | { | |
7782a1a9 IA |
565 | if (_IOC_TYPE(cmd) == SPI_IOC_MAGIC |
566 | && _IOC_NR(cmd) == _IOC_NR(SPI_IOC_MESSAGE(0)) | |
567 | && _IOC_DIR(cmd) == _IOC_WRITE) | |
568 | return spidev_compat_ioc_message(filp, cmd, arg); | |
569 | ||
7d48ec36 BW |
570 | return spidev_ioctl(filp, cmd, (unsigned long)compat_ptr(arg)); |
571 | } | |
572 | #else | |
573 | #define spidev_compat_ioctl NULL | |
574 | #endif /* CONFIG_COMPAT */ | |
575 | ||
814a8d50 AP |
576 | static int spidev_open(struct inode *inode, struct file *filp) |
577 | { | |
578 | struct spidev_data *spidev; | |
579 | int status = -ENXIO; | |
580 | ||
581 | mutex_lock(&device_list_lock); | |
582 | ||
583 | list_for_each_entry(spidev, &device_list, device_entry) { | |
b2c8dadd | 584 | if (spidev->devt == inode->i_rdev) { |
814a8d50 AP |
585 | status = 0; |
586 | break; | |
587 | } | |
588 | } | |
865f6d19 RJ |
589 | |
590 | if (status) { | |
591 | pr_debug("spidev: nothing for minor %d\n", iminor(inode)); | |
592 | goto err_find_dev; | |
593 | } | |
594 | ||
595 | if (!spidev->tx_buffer) { | |
596 | spidev->tx_buffer = kmalloc(bufsiz, GFP_KERNEL); | |
597 | if (!spidev->tx_buffer) { | |
814a8d50 AP |
598 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); |
599 | status = -ENOMEM; | |
865f6d19 | 600 | goto err_find_dev; |
814a8d50 AP |
601 | } |
602 | } | |
865f6d19 RJ |
603 | |
604 | if (!spidev->rx_buffer) { | |
605 | spidev->rx_buffer = kmalloc(bufsiz, GFP_KERNEL); | |
606 | if (!spidev->rx_buffer) { | |
607 | dev_dbg(&spidev->spi->dev, "open/ENOMEM\n"); | |
608 | status = -ENOMEM; | |
609 | goto err_alloc_rx_buf; | |
814a8d50 | 610 | } |
865f6d19 RJ |
611 | } |
612 | ||
613 | spidev->users++; | |
614 | filp->private_data = spidev; | |
615 | nonseekable_open(inode, filp); | |
814a8d50 | 616 | |
865f6d19 RJ |
617 | mutex_unlock(&device_list_lock); |
618 | return 0; | |
619 | ||
620 | err_alloc_rx_buf: | |
621 | kfree(spidev->tx_buffer); | |
622 | spidev->tx_buffer = NULL; | |
623 | err_find_dev: | |
814a8d50 AP |
624 | mutex_unlock(&device_list_lock); |
625 | return status; | |
626 | } | |
627 | ||
628 | static int spidev_release(struct inode *inode, struct file *filp) | |
629 | { | |
630 | struct spidev_data *spidev; | |
631 | int status = 0; | |
632 | ||
633 | mutex_lock(&device_list_lock); | |
634 | spidev = filp->private_data; | |
635 | filp->private_data = NULL; | |
b2c8dadd DB |
636 | |
637 | /* last close? */ | |
814a8d50 AP |
638 | spidev->users--; |
639 | if (!spidev->users) { | |
b2c8dadd DB |
640 | int dofree; |
641 | ||
865f6d19 RJ |
642 | kfree(spidev->tx_buffer); |
643 | spidev->tx_buffer = NULL; | |
644 | ||
645 | kfree(spidev->rx_buffer); | |
646 | spidev->rx_buffer = NULL; | |
b2c8dadd | 647 | |
91690516 MB |
648 | spidev->speed_hz = spidev->spi->max_speed_hz; |
649 | ||
b2c8dadd DB |
650 | /* ... after we unbound from the underlying device? */ |
651 | spin_lock_irq(&spidev->spi_lock); | |
652 | dofree = (spidev->spi == NULL); | |
653 | spin_unlock_irq(&spidev->spi_lock); | |
654 | ||
655 | if (dofree) | |
656 | kfree(spidev); | |
814a8d50 AP |
657 | } |
658 | mutex_unlock(&device_list_lock); | |
659 | ||
660 | return status; | |
661 | } | |
662 | ||
828c0950 | 663 | static const struct file_operations spidev_fops = { |
814a8d50 AP |
664 | .owner = THIS_MODULE, |
665 | /* REVISIT switch to aio primitives, so that userspace | |
666 | * gets more complete API coverage. It'll simplify things | |
667 | * too, except for the locking. | |
668 | */ | |
669 | .write = spidev_write, | |
670 | .read = spidev_read, | |
4ef754b7 | 671 | .unlocked_ioctl = spidev_ioctl, |
7d48ec36 | 672 | .compat_ioctl = spidev_compat_ioctl, |
814a8d50 AP |
673 | .open = spidev_open, |
674 | .release = spidev_release, | |
6038f373 | 675 | .llseek = no_llseek, |
814a8d50 AP |
676 | }; |
677 | ||
678 | /*-------------------------------------------------------------------------*/ | |
679 | ||
680 | /* The main reason to have this class is to make mdev/udev create the | |
681 | * /dev/spidevB.C character device nodes exposing our userspace API. | |
682 | * It also simplifies memory management. | |
683 | */ | |
684 | ||
b2c8dadd | 685 | static struct class *spidev_class; |
814a8d50 AP |
686 | |
687 | /*-------------------------------------------------------------------------*/ | |
688 | ||
fd4a319b | 689 | static int spidev_probe(struct spi_device *spi) |
814a8d50 AP |
690 | { |
691 | struct spidev_data *spidev; | |
692 | int status; | |
693 | unsigned long minor; | |
694 | ||
695 | /* Allocate driver data */ | |
696 | spidev = kzalloc(sizeof(*spidev), GFP_KERNEL); | |
697 | if (!spidev) | |
698 | return -ENOMEM; | |
699 | ||
700 | /* Initialize the driver data */ | |
701 | spidev->spi = spi; | |
25d5cb4b | 702 | spin_lock_init(&spidev->spi_lock); |
814a8d50 AP |
703 | mutex_init(&spidev->buf_lock); |
704 | ||
705 | INIT_LIST_HEAD(&spidev->device_entry); | |
706 | ||
707 | /* If we can allocate a minor number, hook up this device. | |
708 | * Reusing minors is fine so long as udev or mdev is working. | |
709 | */ | |
710 | mutex_lock(&device_list_lock); | |
0a4dd778 | 711 | minor = find_first_zero_bit(minors, N_SPI_MINORS); |
814a8d50 | 712 | if (minor < N_SPI_MINORS) { |
b2c8dadd DB |
713 | struct device *dev; |
714 | ||
715 | spidev->devt = MKDEV(SPIDEV_MAJOR, minor); | |
a9b12619 GKH |
716 | dev = device_create(spidev_class, &spi->dev, spidev->devt, |
717 | spidev, "spidev%d.%d", | |
718 | spi->master->bus_num, spi->chip_select); | |
8c6ffba0 | 719 | status = PTR_ERR_OR_ZERO(dev); |
814a8d50 AP |
720 | } else { |
721 | dev_dbg(&spi->dev, "no minor number available!\n"); | |
722 | status = -ENODEV; | |
723 | } | |
724 | if (status == 0) { | |
725 | set_bit(minor, minors); | |
814a8d50 AP |
726 | list_add(&spidev->device_entry, &device_list); |
727 | } | |
728 | mutex_unlock(&device_list_lock); | |
729 | ||
91690516 MB |
730 | spidev->speed_hz = spi->max_speed_hz; |
731 | ||
aaacf4bb WO |
732 | if (status == 0) |
733 | spi_set_drvdata(spi, spidev); | |
734 | else | |
814a8d50 AP |
735 | kfree(spidev); |
736 | ||
737 | return status; | |
738 | } | |
739 | ||
fd4a319b | 740 | static int spidev_remove(struct spi_device *spi) |
814a8d50 | 741 | { |
b2c8dadd | 742 | struct spidev_data *spidev = spi_get_drvdata(spi); |
814a8d50 | 743 | |
25d5cb4b DB |
744 | /* make sure ops on existing fds can abort cleanly */ |
745 | spin_lock_irq(&spidev->spi_lock); | |
746 | spidev->spi = NULL; | |
747 | spin_unlock_irq(&spidev->spi_lock); | |
814a8d50 | 748 | |
25d5cb4b DB |
749 | /* prevent new opens */ |
750 | mutex_lock(&device_list_lock); | |
814a8d50 | 751 | list_del(&spidev->device_entry); |
b2c8dadd DB |
752 | device_destroy(spidev_class, spidev->devt); |
753 | clear_bit(MINOR(spidev->devt), minors); | |
754 | if (spidev->users == 0) | |
755 | kfree(spidev); | |
814a8d50 AP |
756 | mutex_unlock(&device_list_lock); |
757 | ||
758 | return 0; | |
759 | } | |
760 | ||
880cfd43 | 761 | static const struct of_device_id spidev_dt_ids[] = { |
8fad805b | 762 | { .compatible = "rohm,dh2228fv" }, |
880cfd43 MR |
763 | {}, |
764 | }; | |
765 | ||
766 | MODULE_DEVICE_TABLE(of, spidev_dt_ids); | |
767 | ||
db389b61 | 768 | static struct spi_driver spidev_spi_driver = { |
814a8d50 AP |
769 | .driver = { |
770 | .name = "spidev", | |
771 | .owner = THIS_MODULE, | |
880cfd43 | 772 | .of_match_table = of_match_ptr(spidev_dt_ids), |
814a8d50 AP |
773 | }, |
774 | .probe = spidev_probe, | |
fd4a319b | 775 | .remove = spidev_remove, |
814a8d50 AP |
776 | |
777 | /* NOTE: suspend/resume methods are not necessary here. | |
778 | * We don't do anything except pass the requests to/from | |
779 | * the underlying controller. The refrigerator handles | |
780 | * most issues; the controller driver handles the rest. | |
781 | */ | |
782 | }; | |
783 | ||
784 | /*-------------------------------------------------------------------------*/ | |
785 | ||
786 | static int __init spidev_init(void) | |
787 | { | |
788 | int status; | |
789 | ||
790 | /* Claim our 256 reserved device numbers. Then register a class | |
791 | * that will key udev/mdev to add/remove /dev nodes. Last, register | |
792 | * the driver which manages those device numbers. | |
793 | */ | |
794 | BUILD_BUG_ON(N_SPI_MINORS > 256); | |
795 | status = register_chrdev(SPIDEV_MAJOR, "spi", &spidev_fops); | |
796 | if (status < 0) | |
797 | return status; | |
798 | ||
b2c8dadd DB |
799 | spidev_class = class_create(THIS_MODULE, "spidev"); |
800 | if (IS_ERR(spidev_class)) { | |
db389b61 | 801 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
b2c8dadd | 802 | return PTR_ERR(spidev_class); |
814a8d50 AP |
803 | } |
804 | ||
db389b61 | 805 | status = spi_register_driver(&spidev_spi_driver); |
814a8d50 | 806 | if (status < 0) { |
b2c8dadd | 807 | class_destroy(spidev_class); |
db389b61 | 808 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
809 | } |
810 | return status; | |
811 | } | |
812 | module_init(spidev_init); | |
813 | ||
814 | static void __exit spidev_exit(void) | |
815 | { | |
db389b61 | 816 | spi_unregister_driver(&spidev_spi_driver); |
b2c8dadd | 817 | class_destroy(spidev_class); |
db389b61 | 818 | unregister_chrdev(SPIDEV_MAJOR, spidev_spi_driver.driver.name); |
814a8d50 AP |
819 | } |
820 | module_exit(spidev_exit); | |
821 | ||
822 | MODULE_AUTHOR("Andrea Paterniani, <a.paterniani@swapp-eng.it>"); | |
823 | MODULE_DESCRIPTION("User mode SPI device interface"); | |
824 | MODULE_LICENSE("GPL"); | |
e0626e38 | 825 | MODULE_ALIAS("spi:spidev"); |