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15a0580c DB |
1 | /* |
2 | * mmc_spi.c - Access SD/MMC cards through SPI master controllers | |
3 | * | |
4 | * (C) Copyright 2005, Intec Automation, | |
5 | * Mike Lavender (mike@steroidmicros) | |
6 | * (C) Copyright 2006-2007, David Brownell | |
7 | * (C) Copyright 2007, Axis Communications, | |
8 | * Hans-Peter Nilsson (hp@axis.com) | |
9 | * (C) Copyright 2007, ATRON electronic GmbH, | |
10 | * Jan Nikitenko <jan.nikitenko@gmail.com> | |
11 | * | |
12 | * | |
13 | * This program is free software; you can redistribute it and/or modify | |
14 | * it under the terms of the GNU General Public License as published by | |
15 | * the Free Software Foundation; either version 2 of the License, or | |
16 | * (at your option) any later version. | |
17 | * | |
18 | * This program is distributed in the hope that it will be useful, | |
19 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
20 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
21 | * GNU General Public License for more details. | |
22 | * | |
23 | * You should have received a copy of the GNU General Public License | |
24 | * along with this program; if not, write to the Free Software | |
25 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
26 | */ | |
27 | #include <linux/hrtimer.h> | |
28 | #include <linux/delay.h> | |
23fd5045 | 29 | #include <linux/bio.h> |
15a0580c DB |
30 | #include <linux/dma-mapping.h> |
31 | #include <linux/crc7.h> | |
32 | #include <linux/crc-itu-t.h> | |
33 | ||
34 | #include <linux/mmc/host.h> | |
35 | #include <linux/mmc/mmc.h> /* for R1_SPI_* bit values */ | |
36 | ||
37 | #include <linux/spi/spi.h> | |
38 | #include <linux/spi/mmc_spi.h> | |
39 | ||
40 | #include <asm/unaligned.h> | |
41 | ||
42 | ||
43 | /* NOTES: | |
44 | * | |
45 | * - For now, we won't try to interoperate with a real mmc/sd/sdio | |
46 | * controller, although some of them do have hardware support for | |
47 | * SPI protocol. The main reason for such configs would be mmc-ish | |
48 | * cards like DataFlash, which don't support that "native" protocol. | |
49 | * | |
50 | * We don't have a "DataFlash/MMC/SD/SDIO card slot" abstraction to | |
51 | * switch between driver stacks, and in any case if "native" mode | |
52 | * is available, it will be faster and hence preferable. | |
53 | * | |
54 | * - MMC depends on a different chipselect management policy than the | |
55 | * SPI interface currently supports for shared bus segments: it needs | |
56 | * to issue multiple spi_message requests with the chipselect active, | |
57 | * using the results of one message to decide the next one to issue. | |
58 | * | |
59 | * Pending updates to the programming interface, this driver expects | |
60 | * that it not share the bus with other drivers (precluding conflicts). | |
61 | * | |
62 | * - We tell the controller to keep the chipselect active from the | |
63 | * beginning of an mmc_host_ops.request until the end. So beware | |
64 | * of SPI controller drivers that mis-handle the cs_change flag! | |
65 | * | |
66 | * However, many cards seem OK with chipselect flapping up/down | |
67 | * during that time ... at least on unshared bus segments. | |
68 | */ | |
69 | ||
70 | ||
71 | /* | |
72 | * Local protocol constants, internal to data block protocols. | |
73 | */ | |
74 | ||
75 | /* Response tokens used to ack each block written: */ | |
76 | #define SPI_MMC_RESPONSE_CODE(x) ((x) & 0x1f) | |
77 | #define SPI_RESPONSE_ACCEPTED ((2 << 1)|1) | |
78 | #define SPI_RESPONSE_CRC_ERR ((5 << 1)|1) | |
79 | #define SPI_RESPONSE_WRITE_ERR ((6 << 1)|1) | |
80 | ||
81 | /* Read and write blocks start with these tokens and end with crc; | |
82 | * on error, read tokens act like a subset of R2_SPI_* values. | |
83 | */ | |
84 | #define SPI_TOKEN_SINGLE 0xfe /* single block r/w, multiblock read */ | |
85 | #define SPI_TOKEN_MULTI_WRITE 0xfc /* multiblock write */ | |
86 | #define SPI_TOKEN_STOP_TRAN 0xfd /* terminate multiblock write */ | |
87 | ||
88 | #define MMC_SPI_BLOCKSIZE 512 | |
89 | ||
90 | ||
91 | /* These fixed timeouts come from the latest SD specs, which say to ignore | |
92 | * the CSD values. The R1B value is for card erase (e.g. the "I forgot the | |
93 | * card's password" scenario); it's mostly applied to STOP_TRANSMISSION after | |
94 | * reads which takes nowhere near that long. Older cards may be able to use | |
95 | * shorter timeouts ... but why bother? | |
96 | */ | |
97 | #define readblock_timeout ktime_set(0, 100 * 1000 * 1000) | |
98 | #define writeblock_timeout ktime_set(0, 250 * 1000 * 1000) | |
99 | #define r1b_timeout ktime_set(3, 0) | |
100 | ||
101 | ||
102 | /****************************************************************************/ | |
103 | ||
104 | /* | |
105 | * Local Data Structures | |
106 | */ | |
107 | ||
108 | /* "scratch" is per-{command,block} data exchanged with the card */ | |
109 | struct scratch { | |
110 | u8 status[29]; | |
111 | u8 data_token; | |
112 | __be16 crc_val; | |
113 | }; | |
114 | ||
115 | struct mmc_spi_host { | |
116 | struct mmc_host *mmc; | |
117 | struct spi_device *spi; | |
118 | ||
119 | unsigned char power_mode; | |
120 | u16 powerup_msecs; | |
121 | ||
122 | struct mmc_spi_platform_data *pdata; | |
123 | ||
124 | /* for bulk data transfers */ | |
125 | struct spi_transfer token, t, crc, early_status; | |
126 | struct spi_message m; | |
127 | ||
128 | /* for status readback */ | |
129 | struct spi_transfer status; | |
130 | struct spi_message readback; | |
131 | ||
132 | /* underlying DMA-aware controller, or null */ | |
133 | struct device *dma_dev; | |
134 | ||
135 | /* buffer used for commands and for message "overhead" */ | |
136 | struct scratch *data; | |
137 | dma_addr_t data_dma; | |
138 | ||
139 | /* Specs say to write ones most of the time, even when the card | |
140 | * has no need to read its input data; and many cards won't care. | |
141 | * This is our source of those ones. | |
142 | */ | |
143 | void *ones; | |
144 | dma_addr_t ones_dma; | |
145 | }; | |
146 | ||
147 | ||
148 | /****************************************************************************/ | |
149 | ||
150 | /* | |
151 | * MMC-over-SPI protocol glue, used by the MMC stack interface | |
152 | */ | |
153 | ||
154 | static inline int mmc_cs_off(struct mmc_spi_host *host) | |
155 | { | |
156 | /* chipselect will always be inactive after setup() */ | |
157 | return spi_setup(host->spi); | |
158 | } | |
159 | ||
160 | static int | |
161 | mmc_spi_readbytes(struct mmc_spi_host *host, unsigned len) | |
162 | { | |
163 | int status; | |
164 | ||
165 | if (len > sizeof(*host->data)) { | |
166 | WARN_ON(1); | |
167 | return -EIO; | |
168 | } | |
169 | ||
170 | host->status.len = len; | |
171 | ||
172 | if (host->dma_dev) | |
173 | dma_sync_single_for_device(host->dma_dev, | |
174 | host->data_dma, sizeof(*host->data), | |
175 | DMA_FROM_DEVICE); | |
176 | ||
177 | status = spi_sync(host->spi, &host->readback); | |
178 | if (status == 0) | |
179 | status = host->readback.status; | |
180 | ||
181 | if (host->dma_dev) | |
182 | dma_sync_single_for_cpu(host->dma_dev, | |
183 | host->data_dma, sizeof(*host->data), | |
184 | DMA_FROM_DEVICE); | |
185 | ||
186 | return status; | |
187 | } | |
188 | ||
189 | static int | |
190 | mmc_spi_skip(struct mmc_spi_host *host, ktime_t timeout, unsigned n, u8 byte) | |
191 | { | |
192 | u8 *cp = host->data->status; | |
193 | ||
194 | timeout = ktime_add(timeout, ktime_get()); | |
195 | ||
196 | while (1) { | |
197 | int status; | |
198 | unsigned i; | |
199 | ||
200 | status = mmc_spi_readbytes(host, n); | |
201 | if (status < 0) | |
202 | return status; | |
203 | ||
204 | for (i = 0; i < n; i++) { | |
205 | if (cp[i] != byte) | |
206 | return cp[i]; | |
207 | } | |
208 | ||
209 | /* REVISIT investigate msleep() to avoid busy-wait I/O | |
210 | * in at least some cases. | |
211 | */ | |
212 | if (ktime_to_ns(ktime_sub(ktime_get(), timeout)) > 0) | |
213 | break; | |
214 | } | |
215 | return -ETIMEDOUT; | |
216 | } | |
217 | ||
218 | static inline int | |
219 | mmc_spi_wait_unbusy(struct mmc_spi_host *host, ktime_t timeout) | |
220 | { | |
221 | return mmc_spi_skip(host, timeout, sizeof(host->data->status), 0); | |
222 | } | |
223 | ||
224 | static int mmc_spi_readtoken(struct mmc_spi_host *host) | |
225 | { | |
226 | return mmc_spi_skip(host, readblock_timeout, 1, 0xff); | |
227 | } | |
228 | ||
229 | ||
230 | /* | |
231 | * Note that for SPI, cmd->resp[0] is not the same data as "native" protocol | |
232 | * hosts return! The low byte holds R1_SPI bits. The next byte may hold | |
233 | * R2_SPI bits ... for SEND_STATUS, or after data read errors. | |
234 | * | |
235 | * cmd->resp[1] holds any four-byte response, for R3 (READ_OCR) and on | |
236 | * newer cards R7 (IF_COND). | |
237 | */ | |
238 | ||
239 | static char *maptype(struct mmc_command *cmd) | |
240 | { | |
241 | switch (mmc_spi_resp_type(cmd)) { | |
242 | case MMC_RSP_SPI_R1: return "R1"; | |
243 | case MMC_RSP_SPI_R1B: return "R1B"; | |
244 | case MMC_RSP_SPI_R2: return "R2/R5"; | |
245 | case MMC_RSP_SPI_R3: return "R3/R4/R7"; | |
246 | default: return "?"; | |
247 | } | |
248 | } | |
249 | ||
250 | /* return zero, else negative errno after setting cmd->error */ | |
251 | static int mmc_spi_response_get(struct mmc_spi_host *host, | |
252 | struct mmc_command *cmd, int cs_on) | |
253 | { | |
254 | u8 *cp = host->data->status; | |
255 | u8 *end = cp + host->t.len; | |
256 | int value = 0; | |
257 | char tag[32]; | |
258 | ||
259 | snprintf(tag, sizeof(tag), " ... CMD%d response SPI_%s", | |
260 | cmd->opcode, maptype(cmd)); | |
261 | ||
262 | /* Except for data block reads, the whole response will already | |
263 | * be stored in the scratch buffer. It's somewhere after the | |
264 | * command and the first byte we read after it. We ignore that | |
265 | * first byte. After STOP_TRANSMISSION command it may include | |
266 | * two data bits, but otherwise it's all ones. | |
267 | */ | |
268 | cp += 8; | |
269 | while (cp < end && *cp == 0xff) | |
270 | cp++; | |
271 | ||
272 | /* Data block reads (R1 response types) may need more data... */ | |
273 | if (cp == end) { | |
274 | unsigned i; | |
275 | ||
276 | cp = host->data->status; | |
277 | ||
278 | /* Card sends N(CR) (== 1..8) bytes of all-ones then one | |
279 | * status byte ... and we already scanned 2 bytes. | |
280 | * | |
281 | * REVISIT block read paths use nasty byte-at-a-time I/O | |
282 | * so it can always DMA directly into the target buffer. | |
283 | * It'd probably be better to memcpy() the first chunk and | |
284 | * avoid extra i/o calls... | |
285 | */ | |
286 | for (i = 2; i < 9; i++) { | |
287 | value = mmc_spi_readbytes(host, 1); | |
288 | if (value < 0) | |
289 | goto done; | |
290 | if (*cp != 0xff) | |
291 | goto checkstatus; | |
292 | } | |
293 | value = -ETIMEDOUT; | |
294 | goto done; | |
295 | } | |
296 | ||
297 | checkstatus: | |
298 | if (*cp & 0x80) { | |
299 | dev_dbg(&host->spi->dev, "%s: INVALID RESPONSE, %02x\n", | |
300 | tag, *cp); | |
301 | value = -EBADR; | |
302 | goto done; | |
303 | } | |
304 | ||
305 | cmd->resp[0] = *cp++; | |
306 | cmd->error = 0; | |
307 | ||
308 | /* Status byte: the entire seven-bit R1 response. */ | |
309 | if (cmd->resp[0] != 0) { | |
310 | if ((R1_SPI_PARAMETER | R1_SPI_ADDRESS | |
311 | | R1_SPI_ILLEGAL_COMMAND) | |
312 | & cmd->resp[0]) | |
313 | value = -EINVAL; | |
314 | else if (R1_SPI_COM_CRC & cmd->resp[0]) | |
315 | value = -EILSEQ; | |
316 | else if ((R1_SPI_ERASE_SEQ | R1_SPI_ERASE_RESET) | |
317 | & cmd->resp[0]) | |
318 | value = -EIO; | |
319 | /* else R1_SPI_IDLE, "it's resetting" */ | |
320 | } | |
321 | ||
322 | switch (mmc_spi_resp_type(cmd)) { | |
323 | ||
324 | /* SPI R1B == R1 + busy; STOP_TRANSMISSION (for multiblock reads) | |
325 | * and less-common stuff like various erase operations. | |
326 | */ | |
327 | case MMC_RSP_SPI_R1B: | |
328 | /* maybe we read all the busy tokens already */ | |
329 | while (cp < end && *cp == 0) | |
330 | cp++; | |
331 | if (cp == end) | |
332 | mmc_spi_wait_unbusy(host, r1b_timeout); | |
333 | break; | |
334 | ||
335 | /* SPI R2 == R1 + second status byte; SEND_STATUS | |
336 | * SPI R5 == R1 + data byte; IO_RW_DIRECT | |
337 | */ | |
338 | case MMC_RSP_SPI_R2: | |
339 | cmd->resp[0] |= *cp << 8; | |
340 | break; | |
341 | ||
342 | /* SPI R3, R4, or R7 == R1 + 4 bytes */ | |
343 | case MMC_RSP_SPI_R3: | |
344 | cmd->resp[1] = be32_to_cpu(get_unaligned((u32 *)cp)); | |
345 | break; | |
346 | ||
347 | /* SPI R1 == just one status byte */ | |
348 | case MMC_RSP_SPI_R1: | |
349 | break; | |
350 | ||
351 | default: | |
352 | dev_dbg(&host->spi->dev, "bad response type %04x\n", | |
353 | mmc_spi_resp_type(cmd)); | |
354 | if (value >= 0) | |
355 | value = -EINVAL; | |
356 | goto done; | |
357 | } | |
358 | ||
359 | if (value < 0) | |
360 | dev_dbg(&host->spi->dev, "%s: resp %04x %08x\n", | |
361 | tag, cmd->resp[0], cmd->resp[1]); | |
362 | ||
363 | /* disable chipselect on errors and some success cases */ | |
364 | if (value >= 0 && cs_on) | |
365 | return value; | |
366 | done: | |
367 | if (value < 0) | |
368 | cmd->error = value; | |
369 | mmc_cs_off(host); | |
370 | return value; | |
371 | } | |
372 | ||
373 | /* Issue command and read its response. | |
374 | * Returns zero on success, negative for error. | |
375 | * | |
376 | * On error, caller must cope with mmc core retry mechanism. That | |
377 | * means immediate low-level resubmit, which affects the bus lock... | |
378 | */ | |
379 | static int | |
380 | mmc_spi_command_send(struct mmc_spi_host *host, | |
381 | struct mmc_request *mrq, | |
382 | struct mmc_command *cmd, int cs_on) | |
383 | { | |
384 | struct scratch *data = host->data; | |
385 | u8 *cp = data->status; | |
386 | u32 arg = cmd->arg; | |
387 | int status; | |
388 | struct spi_transfer *t; | |
389 | ||
390 | /* We can handle most commands (except block reads) in one full | |
391 | * duplex I/O operation before either starting the next transfer | |
392 | * (data block or command) or else deselecting the card. | |
393 | * | |
394 | * First, write 7 bytes: | |
395 | * - an all-ones byte to ensure the card is ready | |
396 | * - opcode byte (plus start and transmission bits) | |
397 | * - four bytes of big-endian argument | |
398 | * - crc7 (plus end bit) ... always computed, it's cheap | |
399 | * | |
400 | * We init the whole buffer to all-ones, which is what we need | |
401 | * to write while we're reading (later) response data. | |
402 | */ | |
403 | memset(cp++, 0xff, sizeof(data->status)); | |
404 | ||
405 | *cp++ = 0x40 | cmd->opcode; | |
406 | *cp++ = (u8)(arg >> 24); | |
407 | *cp++ = (u8)(arg >> 16); | |
408 | *cp++ = (u8)(arg >> 8); | |
409 | *cp++ = (u8)arg; | |
410 | *cp++ = (crc7(0, &data->status[1], 5) << 1) | 0x01; | |
411 | ||
412 | /* Then, read up to 13 bytes (while writing all-ones): | |
413 | * - N(CR) (== 1..8) bytes of all-ones | |
414 | * - status byte (for all response types) | |
415 | * - the rest of the response, either: | |
416 | * + nothing, for R1 or R1B responses | |
417 | * + second status byte, for R2 responses | |
418 | * + four data bytes, for R3 and R7 responses | |
419 | * | |
420 | * Finally, read some more bytes ... in the nice cases we know in | |
421 | * advance how many, and reading 1 more is always OK: | |
422 | * - N(EC) (== 0..N) bytes of all-ones, before deselect/finish | |
423 | * - N(RC) (== 1..N) bytes of all-ones, before next command | |
424 | * - N(WR) (== 1..N) bytes of all-ones, before data write | |
425 | * | |
426 | * So in those cases one full duplex I/O of at most 21 bytes will | |
427 | * handle the whole command, leaving the card ready to receive a | |
428 | * data block or new command. We do that whenever we can, shaving | |
429 | * CPU and IRQ costs (especially when using DMA or FIFOs). | |
430 | * | |
431 | * There are two other cases, where it's not generally practical | |
432 | * to rely on a single I/O: | |
433 | * | |
434 | * - R1B responses need at least N(EC) bytes of all-zeroes. | |
435 | * | |
436 | * In this case we can *try* to fit it into one I/O, then | |
437 | * maybe read more data later. | |
438 | * | |
439 | * - Data block reads are more troublesome, since a variable | |
440 | * number of padding bytes precede the token and data. | |
441 | * + N(CX) (== 0..8) bytes of all-ones, before CSD or CID | |
442 | * + N(AC) (== 1..many) bytes of all-ones | |
443 | * | |
444 | * In this case we currently only have minimal speedups here: | |
445 | * when N(CR) == 1 we can avoid I/O in response_get(). | |
446 | */ | |
447 | if (cs_on && (mrq->data->flags & MMC_DATA_READ)) { | |
448 | cp += 2; /* min(N(CR)) + status */ | |
449 | /* R1 */ | |
450 | } else { | |
451 | cp += 10; /* max(N(CR)) + status + min(N(RC),N(WR)) */ | |
452 | if (cmd->flags & MMC_RSP_SPI_S2) /* R2/R5 */ | |
453 | cp++; | |
454 | else if (cmd->flags & MMC_RSP_SPI_B4) /* R3/R4/R7 */ | |
455 | cp += 4; | |
456 | else if (cmd->flags & MMC_RSP_BUSY) /* R1B */ | |
457 | cp = data->status + sizeof(data->status); | |
458 | /* else: R1 (most commands) */ | |
459 | } | |
460 | ||
461 | dev_dbg(&host->spi->dev, " mmc_spi: CMD%d, resp %s\n", | |
462 | cmd->opcode, maptype(cmd)); | |
463 | ||
464 | /* send command, leaving chipselect active */ | |
465 | spi_message_init(&host->m); | |
466 | ||
467 | t = &host->t; | |
468 | memset(t, 0, sizeof(*t)); | |
469 | t->tx_buf = t->rx_buf = data->status; | |
470 | t->tx_dma = t->rx_dma = host->data_dma; | |
471 | t->len = cp - data->status; | |
472 | t->cs_change = 1; | |
473 | spi_message_add_tail(t, &host->m); | |
474 | ||
475 | if (host->dma_dev) { | |
476 | host->m.is_dma_mapped = 1; | |
477 | dma_sync_single_for_device(host->dma_dev, | |
478 | host->data_dma, sizeof(*host->data), | |
479 | DMA_BIDIRECTIONAL); | |
480 | } | |
481 | status = spi_sync(host->spi, &host->m); | |
482 | if (status == 0) | |
483 | status = host->m.status; | |
484 | ||
485 | if (host->dma_dev) | |
486 | dma_sync_single_for_cpu(host->dma_dev, | |
487 | host->data_dma, sizeof(*host->data), | |
488 | DMA_BIDIRECTIONAL); | |
489 | if (status < 0) { | |
490 | dev_dbg(&host->spi->dev, " ... write returned %d\n", status); | |
491 | cmd->error = status; | |
492 | return status; | |
493 | } | |
494 | ||
495 | /* after no-data commands and STOP_TRANSMISSION, chipselect off */ | |
496 | return mmc_spi_response_get(host, cmd, cs_on); | |
497 | } | |
498 | ||
499 | /* Build data message with up to four separate transfers. For TX, we | |
500 | * start by writing the data token. And in most cases, we finish with | |
501 | * a status transfer. | |
502 | * | |
503 | * We always provide TX data for data and CRC. The MMC/SD protocol | |
504 | * requires us to write ones; but Linux defaults to writing zeroes; | |
505 | * so we explicitly initialize it to all ones on RX paths. | |
506 | * | |
507 | * We also handle DMA mapping, so the underlying SPI controller does | |
508 | * not need to (re)do it for each message. | |
509 | */ | |
510 | static void | |
511 | mmc_spi_setup_data_message( | |
512 | struct mmc_spi_host *host, | |
513 | int multiple, | |
514 | enum dma_data_direction direction) | |
515 | { | |
516 | struct spi_transfer *t; | |
517 | struct scratch *scratch = host->data; | |
518 | dma_addr_t dma = host->data_dma; | |
519 | ||
520 | spi_message_init(&host->m); | |
521 | if (dma) | |
522 | host->m.is_dma_mapped = 1; | |
523 | ||
524 | /* for reads, readblock() skips 0xff bytes before finding | |
525 | * the token; for writes, this transfer issues that token. | |
526 | */ | |
527 | if (direction == DMA_TO_DEVICE) { | |
528 | t = &host->token; | |
529 | memset(t, 0, sizeof(*t)); | |
530 | t->len = 1; | |
531 | if (multiple) | |
532 | scratch->data_token = SPI_TOKEN_MULTI_WRITE; | |
533 | else | |
534 | scratch->data_token = SPI_TOKEN_SINGLE; | |
535 | t->tx_buf = &scratch->data_token; | |
536 | if (dma) | |
537 | t->tx_dma = dma + offsetof(struct scratch, data_token); | |
538 | spi_message_add_tail(t, &host->m); | |
539 | } | |
540 | ||
541 | /* Body of transfer is buffer, then CRC ... | |
542 | * either TX-only, or RX with TX-ones. | |
543 | */ | |
544 | t = &host->t; | |
545 | memset(t, 0, sizeof(*t)); | |
546 | t->tx_buf = host->ones; | |
547 | t->tx_dma = host->ones_dma; | |
548 | /* length and actual buffer info are written later */ | |
549 | spi_message_add_tail(t, &host->m); | |
550 | ||
551 | t = &host->crc; | |
552 | memset(t, 0, sizeof(*t)); | |
553 | t->len = 2; | |
554 | if (direction == DMA_TO_DEVICE) { | |
555 | /* the actual CRC may get written later */ | |
556 | t->tx_buf = &scratch->crc_val; | |
557 | if (dma) | |
558 | t->tx_dma = dma + offsetof(struct scratch, crc_val); | |
559 | } else { | |
560 | t->tx_buf = host->ones; | |
561 | t->tx_dma = host->ones_dma; | |
562 | t->rx_buf = &scratch->crc_val; | |
563 | if (dma) | |
564 | t->rx_dma = dma + offsetof(struct scratch, crc_val); | |
565 | } | |
566 | spi_message_add_tail(t, &host->m); | |
567 | ||
568 | /* | |
569 | * A single block read is followed by N(EC) [0+] all-ones bytes | |
570 | * before deselect ... don't bother. | |
571 | * | |
572 | * Multiblock reads are followed by N(AC) [1+] all-ones bytes before | |
573 | * the next block is read, or a STOP_TRANSMISSION is issued. We'll | |
574 | * collect that single byte, so readblock() doesn't need to. | |
575 | * | |
576 | * For a write, the one-byte data response follows immediately, then | |
577 | * come zero or more busy bytes, then N(WR) [1+] all-ones bytes. | |
578 | * Then single block reads may deselect, and multiblock ones issue | |
579 | * the next token (next data block, or STOP_TRAN). We can try to | |
580 | * minimize I/O ops by using a single read to collect end-of-busy. | |
581 | */ | |
582 | if (multiple || direction == DMA_TO_DEVICE) { | |
583 | t = &host->early_status; | |
584 | memset(t, 0, sizeof(*t)); | |
585 | t->len = (direction == DMA_TO_DEVICE) | |
586 | ? sizeof(scratch->status) | |
587 | : 1; | |
588 | t->tx_buf = host->ones; | |
589 | t->tx_dma = host->ones_dma; | |
590 | t->rx_buf = scratch->status; | |
591 | if (dma) | |
592 | t->rx_dma = dma + offsetof(struct scratch, status); | |
593 | t->cs_change = 1; | |
594 | spi_message_add_tail(t, &host->m); | |
595 | } | |
596 | } | |
597 | ||
598 | /* | |
599 | * Write one block: | |
600 | * - caller handled preceding N(WR) [1+] all-ones bytes | |
601 | * - data block | |
602 | * + token | |
603 | * + data bytes | |
604 | * + crc16 | |
605 | * - an all-ones byte ... card writes a data-response byte | |
606 | * - followed by N(EC) [0+] all-ones bytes, card writes zero/'busy' | |
607 | * | |
608 | * Return negative errno, else success. | |
609 | */ | |
610 | static int | |
611 | mmc_spi_writeblock(struct mmc_spi_host *host, struct spi_transfer *t) | |
612 | { | |
613 | struct spi_device *spi = host->spi; | |
614 | int status, i; | |
615 | struct scratch *scratch = host->data; | |
616 | ||
617 | if (host->mmc->use_spi_crc) | |
618 | scratch->crc_val = cpu_to_be16( | |
619 | crc_itu_t(0, t->tx_buf, t->len)); | |
620 | if (host->dma_dev) | |
621 | dma_sync_single_for_device(host->dma_dev, | |
622 | host->data_dma, sizeof(*scratch), | |
623 | DMA_BIDIRECTIONAL); | |
624 | ||
625 | status = spi_sync(spi, &host->m); | |
626 | if (status == 0) | |
627 | status = host->m.status; | |
628 | ||
629 | if (status != 0) { | |
630 | dev_dbg(&spi->dev, "write error (%d)\n", status); | |
631 | return status; | |
632 | } | |
633 | ||
634 | if (host->dma_dev) | |
635 | dma_sync_single_for_cpu(host->dma_dev, | |
636 | host->data_dma, sizeof(*scratch), | |
637 | DMA_BIDIRECTIONAL); | |
638 | ||
639 | /* | |
640 | * Get the transmission data-response reply. It must follow | |
641 | * immediately after the data block we transferred. This reply | |
642 | * doesn't necessarily tell whether the write operation succeeded; | |
643 | * it just says if the transmission was ok and whether *earlier* | |
644 | * writes succeeded; see the standard. | |
645 | */ | |
646 | switch (SPI_MMC_RESPONSE_CODE(scratch->status[0])) { | |
647 | case SPI_RESPONSE_ACCEPTED: | |
648 | status = 0; | |
649 | break; | |
650 | case SPI_RESPONSE_CRC_ERR: | |
651 | /* host shall then issue MMC_STOP_TRANSMISSION */ | |
652 | status = -EILSEQ; | |
653 | break; | |
654 | case SPI_RESPONSE_WRITE_ERR: | |
655 | /* host shall then issue MMC_STOP_TRANSMISSION, | |
656 | * and should MMC_SEND_STATUS to sort it out | |
657 | */ | |
658 | status = -EIO; | |
659 | break; | |
660 | default: | |
661 | status = -EPROTO; | |
662 | break; | |
663 | } | |
664 | if (status != 0) { | |
665 | dev_dbg(&spi->dev, "write error %02x (%d)\n", | |
666 | scratch->status[0], status); | |
667 | return status; | |
668 | } | |
669 | ||
670 | t->tx_buf += t->len; | |
671 | if (host->dma_dev) | |
672 | t->tx_dma += t->len; | |
673 | ||
674 | /* Return when not busy. If we didn't collect that status yet, | |
675 | * we'll need some more I/O. | |
676 | */ | |
677 | for (i = 1; i < sizeof(scratch->status); i++) { | |
678 | if (scratch->status[i] != 0) | |
679 | return 0; | |
680 | } | |
681 | return mmc_spi_wait_unbusy(host, writeblock_timeout); | |
682 | } | |
683 | ||
684 | /* | |
685 | * Read one block: | |
686 | * - skip leading all-ones bytes ... either | |
687 | * + N(AC) [1..f(clock,CSD)] usually, else | |
688 | * + N(CX) [0..8] when reading CSD or CID | |
689 | * - data block | |
690 | * + token ... if error token, no data or crc | |
691 | * + data bytes | |
692 | * + crc16 | |
693 | * | |
694 | * After single block reads, we're done; N(EC) [0+] all-ones bytes follow | |
695 | * before dropping chipselect. | |
696 | * | |
697 | * For multiblock reads, caller either reads the next block or issues a | |
698 | * STOP_TRANSMISSION command. | |
699 | */ | |
700 | static int | |
701 | mmc_spi_readblock(struct mmc_spi_host *host, struct spi_transfer *t) | |
702 | { | |
703 | struct spi_device *spi = host->spi; | |
704 | int status; | |
705 | struct scratch *scratch = host->data; | |
706 | ||
707 | /* At least one SD card sends an all-zeroes byte when N(CX) | |
708 | * applies, before the all-ones bytes ... just cope with that. | |
709 | */ | |
710 | status = mmc_spi_readbytes(host, 1); | |
711 | if (status < 0) | |
712 | return status; | |
713 | status = scratch->status[0]; | |
714 | if (status == 0xff || status == 0) | |
715 | status = mmc_spi_readtoken(host); | |
716 | ||
717 | if (status == SPI_TOKEN_SINGLE) { | |
718 | if (host->dma_dev) { | |
719 | dma_sync_single_for_device(host->dma_dev, | |
720 | host->data_dma, sizeof(*scratch), | |
721 | DMA_BIDIRECTIONAL); | |
722 | dma_sync_single_for_device(host->dma_dev, | |
723 | t->rx_dma, t->len, | |
724 | DMA_FROM_DEVICE); | |
725 | } | |
726 | ||
727 | status = spi_sync(spi, &host->m); | |
728 | if (status == 0) | |
729 | status = host->m.status; | |
730 | ||
731 | if (host->dma_dev) { | |
732 | dma_sync_single_for_cpu(host->dma_dev, | |
733 | host->data_dma, sizeof(*scratch), | |
734 | DMA_BIDIRECTIONAL); | |
735 | dma_sync_single_for_cpu(host->dma_dev, | |
736 | t->rx_dma, t->len, | |
737 | DMA_FROM_DEVICE); | |
738 | } | |
739 | ||
740 | } else { | |
741 | dev_dbg(&spi->dev, "read error %02x (%d)\n", status, status); | |
742 | ||
743 | /* we've read extra garbage, timed out, etc */ | |
744 | if (status < 0) | |
745 | return status; | |
746 | ||
747 | /* low four bits are an R2 subset, fifth seems to be | |
748 | * vendor specific ... map them all to generic error.. | |
749 | */ | |
750 | return -EIO; | |
751 | } | |
752 | ||
753 | if (host->mmc->use_spi_crc) { | |
754 | u16 crc = crc_itu_t(0, t->rx_buf, t->len); | |
755 | ||
756 | be16_to_cpus(&scratch->crc_val); | |
757 | if (scratch->crc_val != crc) { | |
758 | dev_dbg(&spi->dev, "read - crc error: crc_val=0x%04x, " | |
759 | "computed=0x%04x len=%d\n", | |
760 | scratch->crc_val, crc, t->len); | |
761 | return -EILSEQ; | |
762 | } | |
763 | } | |
764 | ||
765 | t->rx_buf += t->len; | |
766 | if (host->dma_dev) | |
767 | t->rx_dma += t->len; | |
768 | ||
769 | return 0; | |
770 | } | |
771 | ||
772 | /* | |
773 | * An MMC/SD data stage includes one or more blocks, optional CRCs, | |
774 | * and inline handshaking. That handhaking makes it unlike most | |
775 | * other SPI protocol stacks. | |
776 | */ | |
777 | static void | |
778 | mmc_spi_data_do(struct mmc_spi_host *host, struct mmc_command *cmd, | |
779 | struct mmc_data *data, u32 blk_size) | |
780 | { | |
781 | struct spi_device *spi = host->spi; | |
782 | struct device *dma_dev = host->dma_dev; | |
783 | struct spi_transfer *t; | |
784 | enum dma_data_direction direction; | |
785 | struct scatterlist *sg; | |
786 | unsigned n_sg; | |
787 | int multiple = (data->blocks > 1); | |
788 | ||
789 | if (data->flags & MMC_DATA_READ) | |
790 | direction = DMA_FROM_DEVICE; | |
791 | else | |
792 | direction = DMA_TO_DEVICE; | |
793 | mmc_spi_setup_data_message(host, multiple, direction); | |
794 | t = &host->t; | |
795 | ||
796 | /* Handle scatterlist segments one at a time, with synch for | |
797 | * each 512-byte block | |
798 | */ | |
799 | for (sg = data->sg, n_sg = data->sg_len; n_sg; n_sg--, sg++) { | |
800 | int status = 0; | |
801 | dma_addr_t dma_addr = 0; | |
802 | void *kmap_addr; | |
803 | unsigned length = sg->length; | |
804 | enum dma_data_direction dir = direction; | |
805 | ||
806 | /* set up dma mapping for controller drivers that might | |
807 | * use DMA ... though they may fall back to PIO | |
808 | */ | |
809 | if (dma_dev) { | |
810 | /* never invalidate whole *shared* pages ... */ | |
811 | if ((sg->offset != 0 || length != PAGE_SIZE) | |
812 | && dir == DMA_FROM_DEVICE) | |
813 | dir = DMA_BIDIRECTIONAL; | |
814 | ||
815 | dma_addr = dma_map_page(dma_dev, sg->page, 0, | |
816 | PAGE_SIZE, dir); | |
817 | if (direction == DMA_TO_DEVICE) | |
818 | t->tx_dma = dma_addr + sg->offset; | |
819 | else | |
820 | t->rx_dma = dma_addr + sg->offset; | |
821 | } | |
822 | ||
823 | /* allow pio too; we don't allow highmem */ | |
824 | kmap_addr = kmap(sg->page); | |
825 | if (direction == DMA_TO_DEVICE) | |
826 | t->tx_buf = kmap_addr + sg->offset; | |
827 | else | |
828 | t->rx_buf = kmap_addr + sg->offset; | |
829 | ||
830 | /* transfer each block, and update request status */ | |
831 | while (length) { | |
832 | t->len = min(length, blk_size); | |
833 | ||
834 | dev_dbg(&host->spi->dev, | |
835 | " mmc_spi: %s block, %d bytes\n", | |
836 | (direction == DMA_TO_DEVICE) | |
837 | ? "write" | |
838 | : "read", | |
839 | t->len); | |
840 | ||
841 | if (direction == DMA_TO_DEVICE) | |
842 | status = mmc_spi_writeblock(host, t); | |
843 | else | |
844 | status = mmc_spi_readblock(host, t); | |
845 | if (status < 0) | |
846 | break; | |
847 | ||
848 | data->bytes_xfered += t->len; | |
849 | length -= t->len; | |
850 | ||
851 | if (!multiple) | |
852 | break; | |
853 | } | |
854 | ||
855 | /* discard mappings */ | |
856 | if (direction == DMA_FROM_DEVICE) | |
857 | flush_kernel_dcache_page(sg->page); | |
858 | kunmap(sg->page); | |
859 | if (dma_dev) | |
860 | dma_unmap_page(dma_dev, dma_addr, PAGE_SIZE, dir); | |
861 | ||
862 | if (status < 0) { | |
863 | data->error = status; | |
864 | dev_dbg(&spi->dev, "%s status %d\n", | |
865 | (direction == DMA_TO_DEVICE) | |
866 | ? "write" : "read", | |
867 | status); | |
868 | break; | |
869 | } | |
870 | } | |
871 | ||
872 | /* NOTE some docs describe an MMC-only SET_BLOCK_COUNT (CMD23) that | |
873 | * can be issued before multiblock writes. Unlike its more widely | |
874 | * documented analogue for SD cards (SET_WR_BLK_ERASE_COUNT, ACMD23), | |
875 | * that can affect the STOP_TRAN logic. Complete (and current) | |
876 | * MMC specs should sort that out before Linux starts using CMD23. | |
877 | */ | |
878 | if (direction == DMA_TO_DEVICE && multiple) { | |
879 | struct scratch *scratch = host->data; | |
880 | int tmp; | |
881 | const unsigned statlen = sizeof(scratch->status); | |
882 | ||
883 | dev_dbg(&spi->dev, " mmc_spi: STOP_TRAN\n"); | |
884 | ||
885 | /* Tweak the per-block message we set up earlier by morphing | |
886 | * it to hold single buffer with the token followed by some | |
887 | * all-ones bytes ... skip N(BR) (0..1), scan the rest for | |
888 | * "not busy any longer" status, and leave chip selected. | |
889 | */ | |
890 | INIT_LIST_HEAD(&host->m.transfers); | |
891 | list_add(&host->early_status.transfer_list, | |
892 | &host->m.transfers); | |
893 | ||
894 | memset(scratch->status, 0xff, statlen); | |
895 | scratch->status[0] = SPI_TOKEN_STOP_TRAN; | |
896 | ||
897 | host->early_status.tx_buf = host->early_status.rx_buf; | |
898 | host->early_status.tx_dma = host->early_status.rx_dma; | |
899 | host->early_status.len = statlen; | |
900 | ||
901 | if (host->dma_dev) | |
902 | dma_sync_single_for_device(host->dma_dev, | |
903 | host->data_dma, sizeof(*scratch), | |
904 | DMA_BIDIRECTIONAL); | |
905 | ||
906 | tmp = spi_sync(spi, &host->m); | |
907 | if (tmp == 0) | |
908 | tmp = host->m.status; | |
909 | ||
910 | if (host->dma_dev) | |
911 | dma_sync_single_for_cpu(host->dma_dev, | |
912 | host->data_dma, sizeof(*scratch), | |
913 | DMA_BIDIRECTIONAL); | |
914 | ||
915 | if (tmp < 0) { | |
916 | if (!data->error) | |
917 | data->error = tmp; | |
918 | return; | |
919 | } | |
920 | ||
921 | /* Ideally we collected "not busy" status with one I/O, | |
922 | * avoiding wasteful byte-at-a-time scanning... but more | |
923 | * I/O is often needed. | |
924 | */ | |
925 | for (tmp = 2; tmp < statlen; tmp++) { | |
926 | if (scratch->status[tmp] != 0) | |
927 | return; | |
928 | } | |
929 | tmp = mmc_spi_wait_unbusy(host, writeblock_timeout); | |
930 | if (tmp < 0 && !data->error) | |
931 | data->error = tmp; | |
932 | } | |
933 | } | |
934 | ||
935 | /****************************************************************************/ | |
936 | ||
937 | /* | |
938 | * MMC driver implementation -- the interface to the MMC stack | |
939 | */ | |
940 | ||
941 | static void mmc_spi_request(struct mmc_host *mmc, struct mmc_request *mrq) | |
942 | { | |
943 | struct mmc_spi_host *host = mmc_priv(mmc); | |
944 | int status = -EINVAL; | |
945 | ||
946 | #ifdef DEBUG | |
947 | /* MMC core and layered drivers *MUST* issue SPI-aware commands */ | |
948 | { | |
949 | struct mmc_command *cmd; | |
950 | int invalid = 0; | |
951 | ||
952 | cmd = mrq->cmd; | |
953 | if (!mmc_spi_resp_type(cmd)) { | |
954 | dev_dbg(&host->spi->dev, "bogus command\n"); | |
955 | cmd->error = -EINVAL; | |
956 | invalid = 1; | |
957 | } | |
958 | ||
959 | cmd = mrq->stop; | |
960 | if (cmd && !mmc_spi_resp_type(cmd)) { | |
961 | dev_dbg(&host->spi->dev, "bogus STOP command\n"); | |
962 | cmd->error = -EINVAL; | |
963 | invalid = 1; | |
964 | } | |
965 | ||
966 | if (invalid) { | |
967 | dump_stack(); | |
968 | mmc_request_done(host->mmc, mrq); | |
969 | return; | |
970 | } | |
971 | } | |
972 | #endif | |
973 | ||
974 | /* issue command; then optionally data and stop */ | |
975 | status = mmc_spi_command_send(host, mrq, mrq->cmd, mrq->data != NULL); | |
976 | if (status == 0 && mrq->data) { | |
977 | mmc_spi_data_do(host, mrq->cmd, mrq->data, mrq->data->blksz); | |
978 | if (mrq->stop) | |
979 | status = mmc_spi_command_send(host, mrq, mrq->stop, 0); | |
980 | else | |
981 | mmc_cs_off(host); | |
982 | } | |
983 | ||
984 | mmc_request_done(host->mmc, mrq); | |
985 | } | |
986 | ||
987 | /* See Section 6.4.1, in SD "Simplified Physical Layer Specification 2.0" | |
988 | * | |
989 | * NOTE that here we can't know that the card has just been powered up; | |
990 | * not all MMC/SD sockets support power switching. | |
991 | * | |
992 | * FIXME when the card is still in SPI mode, e.g. from a previous kernel, | |
993 | * this doesn't seem to do the right thing at all... | |
994 | */ | |
995 | static void mmc_spi_initsequence(struct mmc_spi_host *host) | |
996 | { | |
997 | /* Try to be very sure any previous command has completed; | |
998 | * wait till not-busy, skip debris from any old commands. | |
999 | */ | |
1000 | mmc_spi_wait_unbusy(host, r1b_timeout); | |
1001 | mmc_spi_readbytes(host, 10); | |
1002 | ||
1003 | /* | |
1004 | * Do a burst with chipselect active-high. We need to do this to | |
1005 | * meet the requirement of 74 clock cycles with both chipselect | |
1006 | * and CMD (MOSI) high before CMD0 ... after the card has been | |
1007 | * powered up to Vdd(min), and so is ready to take commands. | |
1008 | * | |
1009 | * Some cards are particularly needy of this (e.g. Viking "SD256") | |
1010 | * while most others don't seem to care. | |
1011 | * | |
1012 | * Note that this is one of the places MMC/SD plays games with the | |
1013 | * SPI protocol. Another is that when chipselect is released while | |
1014 | * the card returns BUSY status, the clock must issue several cycles | |
1015 | * with chipselect high before the card will stop driving its output. | |
1016 | */ | |
1017 | host->spi->mode |= SPI_CS_HIGH; | |
1018 | if (spi_setup(host->spi) != 0) { | |
1019 | /* Just warn; most cards work without it. */ | |
1020 | dev_warn(&host->spi->dev, | |
1021 | "can't change chip-select polarity\n"); | |
1022 | host->spi->mode &= ~SPI_CS_HIGH; | |
1023 | } else { | |
1024 | mmc_spi_readbytes(host, 18); | |
1025 | ||
1026 | host->spi->mode &= ~SPI_CS_HIGH; | |
1027 | if (spi_setup(host->spi) != 0) { | |
1028 | /* Wot, we can't get the same setup we had before? */ | |
1029 | dev_err(&host->spi->dev, | |
1030 | "can't restore chip-select polarity\n"); | |
1031 | } | |
1032 | } | |
1033 | } | |
1034 | ||
1035 | static char *mmc_powerstring(u8 power_mode) | |
1036 | { | |
1037 | switch (power_mode) { | |
1038 | case MMC_POWER_OFF: return "off"; | |
1039 | case MMC_POWER_UP: return "up"; | |
1040 | case MMC_POWER_ON: return "on"; | |
1041 | } | |
1042 | return "?"; | |
1043 | } | |
1044 | ||
1045 | static void mmc_spi_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) | |
1046 | { | |
1047 | struct mmc_spi_host *host = mmc_priv(mmc); | |
1048 | ||
1049 | if (host->power_mode != ios->power_mode) { | |
1050 | int canpower; | |
1051 | ||
1052 | canpower = host->pdata && host->pdata->setpower; | |
1053 | ||
1054 | dev_dbg(&host->spi->dev, "mmc_spi: power %s (%d)%s\n", | |
1055 | mmc_powerstring(ios->power_mode), | |
1056 | ios->vdd, | |
1057 | canpower ? ", can switch" : ""); | |
1058 | ||
1059 | /* switch power on/off if possible, accounting for | |
1060 | * max 250msec powerup time if needed. | |
1061 | */ | |
1062 | if (canpower) { | |
1063 | switch (ios->power_mode) { | |
1064 | case MMC_POWER_OFF: | |
1065 | case MMC_POWER_UP: | |
1066 | host->pdata->setpower(&host->spi->dev, | |
1067 | ios->vdd); | |
1068 | if (ios->power_mode == MMC_POWER_UP) | |
1069 | msleep(host->powerup_msecs); | |
1070 | } | |
1071 | } | |
1072 | ||
1073 | /* See 6.4.1 in the simplified SD card physical spec 2.0 */ | |
1074 | if (ios->power_mode == MMC_POWER_ON) | |
1075 | mmc_spi_initsequence(host); | |
1076 | ||
1077 | /* If powering down, ground all card inputs to avoid power | |
1078 | * delivery from data lines! On a shared SPI bus, this | |
1079 | * will probably be temporary; 6.4.2 of the simplified SD | |
1080 | * spec says this must last at least 1msec. | |
1081 | * | |
1082 | * - Clock low means CPOL 0, e.g. mode 0 | |
1083 | * - MOSI low comes from writing zero | |
1084 | * - Chipselect is usually active low... | |
1085 | */ | |
1086 | if (canpower && ios->power_mode == MMC_POWER_OFF) { | |
1087 | int mres; | |
1088 | ||
1089 | host->spi->mode &= ~(SPI_CPOL|SPI_CPHA); | |
1090 | mres = spi_setup(host->spi); | |
1091 | if (mres < 0) | |
1092 | dev_dbg(&host->spi->dev, | |
1093 | "switch to SPI mode 0 failed\n"); | |
1094 | ||
1095 | if (spi_w8r8(host->spi, 0x00) < 0) | |
1096 | dev_dbg(&host->spi->dev, | |
1097 | "put spi signals to low failed\n"); | |
1098 | ||
1099 | /* | |
1100 | * Now clock should be low due to spi mode 0; | |
1101 | * MOSI should be low because of written 0x00; | |
1102 | * chipselect should be low (it is active low) | |
1103 | * power supply is off, so now MMC is off too! | |
1104 | * | |
1105 | * FIXME no, chipselect can be high since the | |
1106 | * device is inactive and SPI_CS_HIGH is clear... | |
1107 | */ | |
1108 | msleep(10); | |
1109 | if (mres == 0) { | |
1110 | host->spi->mode |= (SPI_CPOL|SPI_CPHA); | |
1111 | mres = spi_setup(host->spi); | |
1112 | if (mres < 0) | |
1113 | dev_dbg(&host->spi->dev, | |
1114 | "switch back to SPI mode 3" | |
1115 | " failed\n"); | |
1116 | } | |
1117 | } | |
1118 | ||
1119 | host->power_mode = ios->power_mode; | |
1120 | } | |
1121 | ||
1122 | if (host->spi->max_speed_hz != ios->clock && ios->clock != 0) { | |
1123 | int status; | |
1124 | ||
1125 | host->spi->max_speed_hz = ios->clock; | |
1126 | status = spi_setup(host->spi); | |
1127 | dev_dbg(&host->spi->dev, | |
1128 | "mmc_spi: clock to %d Hz, %d\n", | |
1129 | host->spi->max_speed_hz, status); | |
1130 | } | |
1131 | } | |
1132 | ||
1133 | static int mmc_spi_get_ro(struct mmc_host *mmc) | |
1134 | { | |
1135 | struct mmc_spi_host *host = mmc_priv(mmc); | |
1136 | ||
1137 | if (host->pdata && host->pdata->get_ro) | |
1138 | return host->pdata->get_ro(mmc->parent); | |
1139 | /* board doesn't support read only detection; assume writeable */ | |
1140 | return 0; | |
1141 | } | |
1142 | ||
1143 | ||
1144 | static const struct mmc_host_ops mmc_spi_ops = { | |
1145 | .request = mmc_spi_request, | |
1146 | .set_ios = mmc_spi_set_ios, | |
1147 | .get_ro = mmc_spi_get_ro, | |
1148 | }; | |
1149 | ||
1150 | ||
1151 | /****************************************************************************/ | |
1152 | ||
1153 | /* | |
1154 | * SPI driver implementation | |
1155 | */ | |
1156 | ||
1157 | static irqreturn_t | |
1158 | mmc_spi_detect_irq(int irq, void *mmc) | |
1159 | { | |
1160 | struct mmc_spi_host *host = mmc_priv(mmc); | |
1161 | u16 delay_msec = max(host->pdata->detect_delay, (u16)100); | |
1162 | ||
1163 | mmc_detect_change(mmc, msecs_to_jiffies(delay_msec)); | |
1164 | return IRQ_HANDLED; | |
1165 | } | |
1166 | ||
1167 | static int mmc_spi_probe(struct spi_device *spi) | |
1168 | { | |
1169 | void *ones; | |
1170 | struct mmc_host *mmc; | |
1171 | struct mmc_spi_host *host; | |
1172 | int status; | |
1173 | ||
1174 | /* MMC and SD specs only seem to care that sampling is on the | |
1175 | * rising edge ... meaning SPI modes 0 or 3. So either SPI mode | |
1176 | * should be legit. We'll use mode 0 since it seems to be a | |
1177 | * bit less troublesome on some hardware ... unclear why. | |
1178 | */ | |
1179 | spi->mode = SPI_MODE_0; | |
1180 | spi->bits_per_word = 8; | |
1181 | ||
1182 | status = spi_setup(spi); | |
1183 | if (status < 0) { | |
1184 | dev_dbg(&spi->dev, "needs SPI mode %02x, %d KHz; %d\n", | |
1185 | spi->mode, spi->max_speed_hz / 1000, | |
1186 | status); | |
1187 | return status; | |
1188 | } | |
1189 | ||
1190 | /* We can use the bus safely iff nobody else will interfere with | |
1191 | * us. That is, either we have the experimental exclusive access | |
1192 | * primitives ... or else there's nobody to share it with. | |
1193 | */ | |
1194 | if (spi->master->num_chipselect > 1) { | |
1195 | struct device *parent = spi->dev.parent; | |
1196 | ||
1197 | /* If there are multiple devices on this bus, we | |
1198 | * can't proceed. | |
1199 | */ | |
1200 | spin_lock(&parent->klist_children.k_lock); | |
1201 | if (parent->klist_children.k_list.next | |
1202 | != parent->klist_children.k_list.prev) | |
1203 | status = -EMLINK; | |
1204 | else | |
1205 | status = 0; | |
1206 | spin_unlock(&parent->klist_children.k_lock); | |
1207 | if (status < 0) { | |
1208 | dev_err(&spi->dev, "can't share SPI bus\n"); | |
1209 | return status; | |
1210 | } | |
1211 | ||
1212 | /* REVISIT we can't guarantee another device won't | |
1213 | * be added later. It's uncommon though ... for now, | |
1214 | * work as if this is safe. | |
1215 | */ | |
1216 | dev_warn(&spi->dev, "ASSUMING unshared SPI bus!\n"); | |
1217 | } | |
1218 | ||
1219 | /* We need a supply of ones to transmit. This is the only time | |
1220 | * the CPU touches these, so cache coherency isn't a concern. | |
1221 | * | |
1222 | * NOTE if many systems use more than one MMC-over-SPI connector | |
1223 | * it'd save some memory to share this. That's evidently rare. | |
1224 | */ | |
1225 | status = -ENOMEM; | |
1226 | ones = kmalloc(MMC_SPI_BLOCKSIZE, GFP_KERNEL); | |
1227 | if (!ones) | |
1228 | goto nomem; | |
1229 | memset(ones, 0xff, MMC_SPI_BLOCKSIZE); | |
1230 | ||
1231 | mmc = mmc_alloc_host(sizeof(*host), &spi->dev); | |
1232 | if (!mmc) | |
1233 | goto nomem; | |
1234 | ||
1235 | mmc->ops = &mmc_spi_ops; | |
1236 | mmc->max_blk_size = MMC_SPI_BLOCKSIZE; | |
1237 | ||
1238 | /* As long as we keep track of the number of successfully | |
1239 | * transmitted blocks, we're good for multiwrite. | |
1240 | */ | |
1241 | mmc->caps = MMC_CAP_SPI | MMC_CAP_MULTIWRITE; | |
1242 | ||
1243 | /* SPI doesn't need the lowspeed device identification thing for | |
1244 | * MMC or SD cards, since it never comes up in open drain mode. | |
1245 | * That's good; some SPI masters can't handle very low speeds! | |
1246 | * | |
1247 | * However, low speed SDIO cards need not handle over 400 KHz; | |
1248 | * that's the only reason not to use a few MHz for f_min (until | |
1249 | * the upper layer reads the target frequency from the CSD). | |
1250 | */ | |
1251 | mmc->f_min = 400000; | |
1252 | mmc->f_max = spi->max_speed_hz; | |
1253 | ||
1254 | host = mmc_priv(mmc); | |
1255 | host->mmc = mmc; | |
1256 | host->spi = spi; | |
1257 | ||
1258 | host->ones = ones; | |
1259 | ||
1260 | /* Platform data is used to hook up things like card sensing | |
1261 | * and power switching gpios. | |
1262 | */ | |
1263 | host->pdata = spi->dev.platform_data; | |
1264 | if (host->pdata) | |
1265 | mmc->ocr_avail = host->pdata->ocr_mask; | |
1266 | if (!mmc->ocr_avail) { | |
1267 | dev_warn(&spi->dev, "ASSUMING 3.2-3.4 V slot power\n"); | |
1268 | mmc->ocr_avail = MMC_VDD_32_33|MMC_VDD_33_34; | |
1269 | } | |
1270 | if (host->pdata && host->pdata->setpower) { | |
1271 | host->powerup_msecs = host->pdata->powerup_msecs; | |
1272 | if (!host->powerup_msecs || host->powerup_msecs > 250) | |
1273 | host->powerup_msecs = 250; | |
1274 | } | |
1275 | ||
1276 | dev_set_drvdata(&spi->dev, mmc); | |
1277 | ||
1278 | /* preallocate dma buffers */ | |
1279 | host->data = kmalloc(sizeof(*host->data), GFP_KERNEL); | |
1280 | if (!host->data) | |
1281 | goto fail_nobuf1; | |
1282 | ||
1283 | if (spi->master->cdev.dev->dma_mask) { | |
1284 | struct device *dev = spi->master->cdev.dev; | |
1285 | ||
1286 | host->dma_dev = dev; | |
1287 | host->ones_dma = dma_map_single(dev, ones, | |
1288 | MMC_SPI_BLOCKSIZE, DMA_TO_DEVICE); | |
1289 | host->data_dma = dma_map_single(dev, host->data, | |
1290 | sizeof(*host->data), DMA_BIDIRECTIONAL); | |
1291 | ||
1292 | /* REVISIT in theory those map operations can fail... */ | |
1293 | ||
1294 | dma_sync_single_for_cpu(host->dma_dev, | |
1295 | host->data_dma, sizeof(*host->data), | |
1296 | DMA_BIDIRECTIONAL); | |
1297 | } | |
1298 | ||
1299 | /* setup message for status/busy readback */ | |
1300 | spi_message_init(&host->readback); | |
1301 | host->readback.is_dma_mapped = (host->dma_dev != NULL); | |
1302 | ||
1303 | spi_message_add_tail(&host->status, &host->readback); | |
1304 | host->status.tx_buf = host->ones; | |
1305 | host->status.tx_dma = host->ones_dma; | |
1306 | host->status.rx_buf = &host->data->status; | |
1307 | host->status.rx_dma = host->data_dma + offsetof(struct scratch, status); | |
1308 | host->status.cs_change = 1; | |
1309 | ||
1310 | /* register card detect irq */ | |
1311 | if (host->pdata && host->pdata->init) { | |
1312 | status = host->pdata->init(&spi->dev, mmc_spi_detect_irq, mmc); | |
1313 | if (status != 0) | |
1314 | goto fail_glue_init; | |
1315 | } | |
1316 | ||
1317 | status = mmc_add_host(mmc); | |
1318 | if (status != 0) | |
1319 | goto fail_add_host; | |
1320 | ||
1321 | dev_info(&spi->dev, "SD/MMC host %s%s%s%s\n", | |
1322 | mmc->class_dev.bus_id, | |
1323 | host->dma_dev ? "" : ", no DMA", | |
1324 | (host->pdata && host->pdata->get_ro) | |
1325 | ? "" : ", no WP", | |
1326 | (host->pdata && host->pdata->setpower) | |
1327 | ? "" : ", no poweroff"); | |
1328 | return 0; | |
1329 | ||
1330 | fail_add_host: | |
1331 | mmc_remove_host (mmc); | |
1332 | fail_glue_init: | |
1333 | if (host->dma_dev) | |
1334 | dma_unmap_single(host->dma_dev, host->data_dma, | |
1335 | sizeof(*host->data), DMA_BIDIRECTIONAL); | |
1336 | kfree(host->data); | |
1337 | ||
1338 | fail_nobuf1: | |
1339 | mmc_free_host(mmc); | |
1340 | dev_set_drvdata(&spi->dev, NULL); | |
1341 | ||
1342 | nomem: | |
1343 | kfree(ones); | |
1344 | return status; | |
1345 | } | |
1346 | ||
1347 | ||
1348 | static int __devexit mmc_spi_remove(struct spi_device *spi) | |
1349 | { | |
1350 | struct mmc_host *mmc = dev_get_drvdata(&spi->dev); | |
1351 | struct mmc_spi_host *host; | |
1352 | ||
1353 | if (mmc) { | |
1354 | host = mmc_priv(mmc); | |
1355 | ||
1356 | /* prevent new mmc_detect_change() calls */ | |
1357 | if (host->pdata && host->pdata->exit) | |
1358 | host->pdata->exit(&spi->dev, mmc); | |
1359 | ||
1360 | mmc_remove_host(mmc); | |
1361 | ||
1362 | if (host->dma_dev) { | |
1363 | dma_unmap_single(host->dma_dev, host->ones_dma, | |
1364 | MMC_SPI_BLOCKSIZE, DMA_TO_DEVICE); | |
1365 | dma_unmap_single(host->dma_dev, host->data_dma, | |
1366 | sizeof(*host->data), DMA_BIDIRECTIONAL); | |
1367 | } | |
1368 | ||
1369 | kfree(host->data); | |
1370 | kfree(host->ones); | |
1371 | ||
1372 | spi->max_speed_hz = mmc->f_max; | |
1373 | mmc_free_host(mmc); | |
1374 | dev_set_drvdata(&spi->dev, NULL); | |
1375 | } | |
1376 | return 0; | |
1377 | } | |
1378 | ||
1379 | ||
1380 | static struct spi_driver mmc_spi_driver = { | |
1381 | .driver = { | |
1382 | .name = "mmc_spi", | |
1383 | .bus = &spi_bus_type, | |
1384 | .owner = THIS_MODULE, | |
1385 | }, | |
1386 | .probe = mmc_spi_probe, | |
1387 | .remove = __devexit_p(mmc_spi_remove), | |
1388 | }; | |
1389 | ||
1390 | ||
1391 | static int __init mmc_spi_init(void) | |
1392 | { | |
1393 | return spi_register_driver(&mmc_spi_driver); | |
1394 | } | |
1395 | module_init(mmc_spi_init); | |
1396 | ||
1397 | ||
1398 | static void __exit mmc_spi_exit(void) | |
1399 | { | |
1400 | spi_unregister_driver(&mmc_spi_driver); | |
1401 | } | |
1402 | module_exit(mmc_spi_exit); | |
1403 | ||
1404 | ||
1405 | MODULE_AUTHOR("Mike Lavender, David Brownell, " | |
1406 | "Hans-Peter Nilsson, Jan Nikitenko"); | |
1407 | MODULE_DESCRIPTION("SPI SD/MMC host driver"); | |
1408 | MODULE_LICENSE("GPL"); |