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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/sched.h> | |
28 | #include <linux/delay.h> | |
29 | #include <linux/slab.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/bio.h> | |
32 | #include <linux/dma-mapping.h> | |
33 | #include <linux/crc7.h> | |
34 | #include <linux/crc-itu-t.h> | |
35 | #include <linux/scatterlist.h> | |
36 | ||
37 | #include <linux/mmc/host.h> | |
38 | #include <linux/mmc/mmc.h> /* for R1_SPI_* bit values */ | |
39 | #include <linux/mmc/slot-gpio.h> | |
40 | ||
41 | #include <linux/spi/spi.h> | |
42 | #include <linux/spi/mmc_spi.h> | |
43 | ||
44 | #include <asm/unaligned.h> | |
45 | ||
46 | ||
47 | /* NOTES: | |
48 | * | |
49 | * - For now, we won't try to interoperate with a real mmc/sd/sdio | |
50 | * controller, although some of them do have hardware support for | |
51 | * SPI protocol. The main reason for such configs would be mmc-ish | |
52 | * cards like DataFlash, which don't support that "native" protocol. | |
53 | * | |
54 | * We don't have a "DataFlash/MMC/SD/SDIO card slot" abstraction to | |
55 | * switch between driver stacks, and in any case if "native" mode | |
56 | * is available, it will be faster and hence preferable. | |
57 | * | |
58 | * - MMC depends on a different chipselect management policy than the | |
59 | * SPI interface currently supports for shared bus segments: it needs | |
60 | * to issue multiple spi_message requests with the chipselect active, | |
61 | * using the results of one message to decide the next one to issue. | |
62 | * | |
63 | * Pending updates to the programming interface, this driver expects | |
64 | * that it not share the bus with other drivers (precluding conflicts). | |
65 | * | |
66 | * - We tell the controller to keep the chipselect active from the | |
67 | * beginning of an mmc_host_ops.request until the end. So beware | |
68 | * of SPI controller drivers that mis-handle the cs_change flag! | |
69 | * | |
70 | * However, many cards seem OK with chipselect flapping up/down | |
71 | * during that time ... at least on unshared bus segments. | |
72 | */ | |
73 | ||
74 | ||
75 | /* | |
76 | * Local protocol constants, internal to data block protocols. | |
77 | */ | |
78 | ||
79 | /* Response tokens used to ack each block written: */ | |
80 | #define SPI_MMC_RESPONSE_CODE(x) ((x) & 0x1f) | |
81 | #define SPI_RESPONSE_ACCEPTED ((2 << 1)|1) | |
82 | #define SPI_RESPONSE_CRC_ERR ((5 << 1)|1) | |
83 | #define SPI_RESPONSE_WRITE_ERR ((6 << 1)|1) | |
84 | ||
85 | /* Read and write blocks start with these tokens and end with crc; | |
86 | * on error, read tokens act like a subset of R2_SPI_* values. | |
87 | */ | |
88 | #define SPI_TOKEN_SINGLE 0xfe /* single block r/w, multiblock read */ | |
89 | #define SPI_TOKEN_MULTI_WRITE 0xfc /* multiblock write */ | |
90 | #define SPI_TOKEN_STOP_TRAN 0xfd /* terminate multiblock write */ | |
91 | ||
92 | #define MMC_SPI_BLOCKSIZE 512 | |
93 | ||
94 | ||
95 | /* These fixed timeouts come from the latest SD specs, which say to ignore | |
96 | * the CSD values. The R1B value is for card erase (e.g. the "I forgot the | |
97 | * card's password" scenario); it's mostly applied to STOP_TRANSMISSION after | |
98 | * reads which takes nowhere near that long. Older cards may be able to use | |
99 | * shorter timeouts ... but why bother? | |
100 | */ | |
101 | #define r1b_timeout (HZ * 3) | |
102 | ||
103 | /* One of the critical speed parameters is the amount of data which may | |
104 | * be transferred in one command. If this value is too low, the SD card | |
105 | * controller has to do multiple partial block writes (argggh!). With | |
106 | * today (2008) SD cards there is little speed gain if we transfer more | |
107 | * than 64 KBytes at a time. So use this value until there is any indication | |
108 | * that we should do more here. | |
109 | */ | |
110 | #define MMC_SPI_BLOCKSATONCE 128 | |
111 | ||
112 | /****************************************************************************/ | |
113 | ||
114 | /* | |
115 | * Local Data Structures | |
116 | */ | |
117 | ||
118 | /* "scratch" is per-{command,block} data exchanged with the card */ | |
119 | struct scratch { | |
120 | u8 status[29]; | |
121 | u8 data_token; | |
122 | __be16 crc_val; | |
123 | }; | |
124 | ||
125 | struct mmc_spi_host { | |
126 | struct mmc_host *mmc; | |
127 | struct spi_device *spi; | |
128 | ||
129 | unsigned char power_mode; | |
130 | u16 powerup_msecs; | |
131 | ||
132 | struct mmc_spi_platform_data *pdata; | |
133 | ||
134 | /* for bulk data transfers */ | |
135 | struct spi_transfer token, t, crc, early_status; | |
136 | struct spi_message m; | |
137 | ||
138 | /* for status readback */ | |
139 | struct spi_transfer status; | |
140 | struct spi_message readback; | |
141 | ||
142 | /* underlying DMA-aware controller, or null */ | |
143 | struct device *dma_dev; | |
144 | ||
145 | /* buffer used for commands and for message "overhead" */ | |
146 | struct scratch *data; | |
147 | dma_addr_t data_dma; | |
148 | ||
149 | /* Specs say to write ones most of the time, even when the card | |
150 | * has no need to read its input data; and many cards won't care. | |
151 | * This is our source of those ones. | |
152 | */ | |
153 | void *ones; | |
154 | dma_addr_t ones_dma; | |
155 | }; | |
156 | ||
157 | ||
158 | /****************************************************************************/ | |
159 | ||
160 | /* | |
161 | * MMC-over-SPI protocol glue, used by the MMC stack interface | |
162 | */ | |
163 | ||
164 | static inline int mmc_cs_off(struct mmc_spi_host *host) | |
165 | { | |
166 | /* chipselect will always be inactive after setup() */ | |
167 | return spi_setup(host->spi); | |
168 | } | |
169 | ||
170 | static int | |
171 | mmc_spi_readbytes(struct mmc_spi_host *host, unsigned len) | |
172 | { | |
173 | int status; | |
174 | ||
175 | if (len > sizeof(*host->data)) { | |
176 | WARN_ON(1); | |
177 | return -EIO; | |
178 | } | |
179 | ||
180 | host->status.len = len; | |
181 | ||
182 | if (host->dma_dev) | |
183 | dma_sync_single_for_device(host->dma_dev, | |
184 | host->data_dma, sizeof(*host->data), | |
185 | DMA_FROM_DEVICE); | |
186 | ||
187 | status = spi_sync_locked(host->spi, &host->readback); | |
188 | ||
189 | if (host->dma_dev) | |
190 | dma_sync_single_for_cpu(host->dma_dev, | |
191 | host->data_dma, sizeof(*host->data), | |
192 | DMA_FROM_DEVICE); | |
193 | ||
194 | return status; | |
195 | } | |
196 | ||
197 | static int mmc_spi_skip(struct mmc_spi_host *host, unsigned long timeout, | |
198 | unsigned n, u8 byte) | |
199 | { | |
200 | u8 *cp = host->data->status; | |
201 | unsigned long start = jiffies; | |
202 | ||
203 | while (1) { | |
204 | int status; | |
205 | unsigned i; | |
206 | ||
207 | status = mmc_spi_readbytes(host, n); | |
208 | if (status < 0) | |
209 | return status; | |
210 | ||
211 | for (i = 0; i < n; i++) { | |
212 | if (cp[i] != byte) | |
213 | return cp[i]; | |
214 | } | |
215 | ||
216 | if (time_is_before_jiffies(start + timeout)) | |
217 | break; | |
218 | ||
219 | /* If we need long timeouts, we may release the CPU. | |
220 | * We use jiffies here because we want to have a relation | |
221 | * between elapsed time and the blocking of the scheduler. | |
222 | */ | |
223 | if (time_is_before_jiffies(start+1)) | |
224 | schedule(); | |
225 | } | |
226 | return -ETIMEDOUT; | |
227 | } | |
228 | ||
229 | static inline int | |
230 | mmc_spi_wait_unbusy(struct mmc_spi_host *host, unsigned long timeout) | |
231 | { | |
232 | return mmc_spi_skip(host, timeout, sizeof(host->data->status), 0); | |
233 | } | |
234 | ||
235 | static int mmc_spi_readtoken(struct mmc_spi_host *host, unsigned long timeout) | |
236 | { | |
237 | return mmc_spi_skip(host, timeout, 1, 0xff); | |
238 | } | |
239 | ||
240 | ||
241 | /* | |
242 | * Note that for SPI, cmd->resp[0] is not the same data as "native" protocol | |
243 | * hosts return! The low byte holds R1_SPI bits. The next byte may hold | |
244 | * R2_SPI bits ... for SEND_STATUS, or after data read errors. | |
245 | * | |
246 | * cmd->resp[1] holds any four-byte response, for R3 (READ_OCR) and on | |
247 | * newer cards R7 (IF_COND). | |
248 | */ | |
249 | ||
250 | static char *maptype(struct mmc_command *cmd) | |
251 | { | |
252 | switch (mmc_spi_resp_type(cmd)) { | |
253 | case MMC_RSP_SPI_R1: return "R1"; | |
254 | case MMC_RSP_SPI_R1B: return "R1B"; | |
255 | case MMC_RSP_SPI_R2: return "R2/R5"; | |
256 | case MMC_RSP_SPI_R3: return "R3/R4/R7"; | |
257 | default: return "?"; | |
258 | } | |
259 | } | |
260 | ||
261 | /* return zero, else negative errno after setting cmd->error */ | |
262 | static int mmc_spi_response_get(struct mmc_spi_host *host, | |
263 | struct mmc_command *cmd, int cs_on) | |
264 | { | |
265 | u8 *cp = host->data->status; | |
266 | u8 *end = cp + host->t.len; | |
267 | int value = 0; | |
268 | int bitshift; | |
269 | u8 leftover = 0; | |
270 | unsigned short rotator; | |
271 | int i; | |
272 | char tag[32]; | |
273 | ||
274 | snprintf(tag, sizeof(tag), " ... CMD%d response SPI_%s", | |
275 | cmd->opcode, maptype(cmd)); | |
276 | ||
277 | /* Except for data block reads, the whole response will already | |
278 | * be stored in the scratch buffer. It's somewhere after the | |
279 | * command and the first byte we read after it. We ignore that | |
280 | * first byte. After STOP_TRANSMISSION command it may include | |
281 | * two data bits, but otherwise it's all ones. | |
282 | */ | |
283 | cp += 8; | |
284 | while (cp < end && *cp == 0xff) | |
285 | cp++; | |
286 | ||
287 | /* Data block reads (R1 response types) may need more data... */ | |
288 | if (cp == end) { | |
289 | cp = host->data->status; | |
290 | end = cp+1; | |
291 | ||
292 | /* Card sends N(CR) (== 1..8) bytes of all-ones then one | |
293 | * status byte ... and we already scanned 2 bytes. | |
294 | * | |
295 | * REVISIT block read paths use nasty byte-at-a-time I/O | |
296 | * so it can always DMA directly into the target buffer. | |
297 | * It'd probably be better to memcpy() the first chunk and | |
298 | * avoid extra i/o calls... | |
299 | * | |
300 | * Note we check for more than 8 bytes, because in practice, | |
301 | * some SD cards are slow... | |
302 | */ | |
303 | for (i = 2; i < 16; i++) { | |
304 | value = mmc_spi_readbytes(host, 1); | |
305 | if (value < 0) | |
306 | goto done; | |
307 | if (*cp != 0xff) | |
308 | goto checkstatus; | |
309 | } | |
310 | value = -ETIMEDOUT; | |
311 | goto done; | |
312 | } | |
313 | ||
314 | checkstatus: | |
315 | bitshift = 0; | |
316 | if (*cp & 0x80) { | |
317 | /* Houston, we have an ugly card with a bit-shifted response */ | |
318 | rotator = *cp++ << 8; | |
319 | /* read the next byte */ | |
320 | if (cp == end) { | |
321 | value = mmc_spi_readbytes(host, 1); | |
322 | if (value < 0) | |
323 | goto done; | |
324 | cp = host->data->status; | |
325 | end = cp+1; | |
326 | } | |
327 | rotator |= *cp++; | |
328 | while (rotator & 0x8000) { | |
329 | bitshift++; | |
330 | rotator <<= 1; | |
331 | } | |
332 | cmd->resp[0] = rotator >> 8; | |
333 | leftover = rotator; | |
334 | } else { | |
335 | cmd->resp[0] = *cp++; | |
336 | } | |
337 | cmd->error = 0; | |
338 | ||
339 | /* Status byte: the entire seven-bit R1 response. */ | |
340 | if (cmd->resp[0] != 0) { | |
341 | if ((R1_SPI_PARAMETER | R1_SPI_ADDRESS) | |
342 | & cmd->resp[0]) | |
343 | value = -EFAULT; /* Bad address */ | |
344 | else if (R1_SPI_ILLEGAL_COMMAND & cmd->resp[0]) | |
345 | value = -ENOSYS; /* Function not implemented */ | |
346 | else if (R1_SPI_COM_CRC & cmd->resp[0]) | |
347 | value = -EILSEQ; /* Illegal byte sequence */ | |
348 | else if ((R1_SPI_ERASE_SEQ | R1_SPI_ERASE_RESET) | |
349 | & cmd->resp[0]) | |
350 | value = -EIO; /* I/O error */ | |
351 | /* else R1_SPI_IDLE, "it's resetting" */ | |
352 | } | |
353 | ||
354 | switch (mmc_spi_resp_type(cmd)) { | |
355 | ||
356 | /* SPI R1B == R1 + busy; STOP_TRANSMISSION (for multiblock reads) | |
357 | * and less-common stuff like various erase operations. | |
358 | */ | |
359 | case MMC_RSP_SPI_R1B: | |
360 | /* maybe we read all the busy tokens already */ | |
361 | while (cp < end && *cp == 0) | |
362 | cp++; | |
363 | if (cp == end) | |
364 | mmc_spi_wait_unbusy(host, r1b_timeout); | |
365 | break; | |
366 | ||
367 | /* SPI R2 == R1 + second status byte; SEND_STATUS | |
368 | * SPI R5 == R1 + data byte; IO_RW_DIRECT | |
369 | */ | |
370 | case MMC_RSP_SPI_R2: | |
371 | /* read the next byte */ | |
372 | if (cp == end) { | |
373 | value = mmc_spi_readbytes(host, 1); | |
374 | if (value < 0) | |
375 | goto done; | |
376 | cp = host->data->status; | |
377 | end = cp+1; | |
378 | } | |
379 | if (bitshift) { | |
380 | rotator = leftover << 8; | |
381 | rotator |= *cp << bitshift; | |
382 | cmd->resp[0] |= (rotator & 0xFF00); | |
383 | } else { | |
384 | cmd->resp[0] |= *cp << 8; | |
385 | } | |
386 | break; | |
387 | ||
388 | /* SPI R3, R4, or R7 == R1 + 4 bytes */ | |
389 | case MMC_RSP_SPI_R3: | |
390 | rotator = leftover << 8; | |
391 | cmd->resp[1] = 0; | |
392 | for (i = 0; i < 4; i++) { | |
393 | cmd->resp[1] <<= 8; | |
394 | /* read the next byte */ | |
395 | if (cp == end) { | |
396 | value = mmc_spi_readbytes(host, 1); | |
397 | if (value < 0) | |
398 | goto done; | |
399 | cp = host->data->status; | |
400 | end = cp+1; | |
401 | } | |
402 | if (bitshift) { | |
403 | rotator |= *cp++ << bitshift; | |
404 | cmd->resp[1] |= (rotator >> 8); | |
405 | rotator <<= 8; | |
406 | } else { | |
407 | cmd->resp[1] |= *cp++; | |
408 | } | |
409 | } | |
410 | break; | |
411 | ||
412 | /* SPI R1 == just one status byte */ | |
413 | case MMC_RSP_SPI_R1: | |
414 | break; | |
415 | ||
416 | default: | |
417 | dev_dbg(&host->spi->dev, "bad response type %04x\n", | |
418 | mmc_spi_resp_type(cmd)); | |
419 | if (value >= 0) | |
420 | value = -EINVAL; | |
421 | goto done; | |
422 | } | |
423 | ||
424 | if (value < 0) | |
425 | dev_dbg(&host->spi->dev, "%s: resp %04x %08x\n", | |
426 | tag, cmd->resp[0], cmd->resp[1]); | |
427 | ||
428 | /* disable chipselect on errors and some success cases */ | |
429 | if (value >= 0 && cs_on) | |
430 | return value; | |
431 | done: | |
432 | if (value < 0) | |
433 | cmd->error = value; | |
434 | mmc_cs_off(host); | |
435 | return value; | |
436 | } | |
437 | ||
438 | /* Issue command and read its response. | |
439 | * Returns zero on success, negative for error. | |
440 | * | |
441 | * On error, caller must cope with mmc core retry mechanism. That | |
442 | * means immediate low-level resubmit, which affects the bus lock... | |
443 | */ | |
444 | static int | |
445 | mmc_spi_command_send(struct mmc_spi_host *host, | |
446 | struct mmc_request *mrq, | |
447 | struct mmc_command *cmd, int cs_on) | |
448 | { | |
449 | struct scratch *data = host->data; | |
450 | u8 *cp = data->status; | |
451 | int status; | |
452 | struct spi_transfer *t; | |
453 | ||
454 | /* We can handle most commands (except block reads) in one full | |
455 | * duplex I/O operation before either starting the next transfer | |
456 | * (data block or command) or else deselecting the card. | |
457 | * | |
458 | * First, write 7 bytes: | |
459 | * - an all-ones byte to ensure the card is ready | |
460 | * - opcode byte (plus start and transmission bits) | |
461 | * - four bytes of big-endian argument | |
462 | * - crc7 (plus end bit) ... always computed, it's cheap | |
463 | * | |
464 | * We init the whole buffer to all-ones, which is what we need | |
465 | * to write while we're reading (later) response data. | |
466 | */ | |
467 | memset(cp, 0xff, sizeof(data->status)); | |
468 | ||
469 | cp[1] = 0x40 | cmd->opcode; | |
470 | put_unaligned_be32(cmd->arg, cp+2); | |
471 | cp[6] = crc7_be(0, cp+1, 5) | 0x01; | |
472 | cp += 7; | |
473 | ||
474 | /* Then, read up to 13 bytes (while writing all-ones): | |
475 | * - N(CR) (== 1..8) bytes of all-ones | |
476 | * - status byte (for all response types) | |
477 | * - the rest of the response, either: | |
478 | * + nothing, for R1 or R1B responses | |
479 | * + second status byte, for R2 responses | |
480 | * + four data bytes, for R3 and R7 responses | |
481 | * | |
482 | * Finally, read some more bytes ... in the nice cases we know in | |
483 | * advance how many, and reading 1 more is always OK: | |
484 | * - N(EC) (== 0..N) bytes of all-ones, before deselect/finish | |
485 | * - N(RC) (== 1..N) bytes of all-ones, before next command | |
486 | * - N(WR) (== 1..N) bytes of all-ones, before data write | |
487 | * | |
488 | * So in those cases one full duplex I/O of at most 21 bytes will | |
489 | * handle the whole command, leaving the card ready to receive a | |
490 | * data block or new command. We do that whenever we can, shaving | |
491 | * CPU and IRQ costs (especially when using DMA or FIFOs). | |
492 | * | |
493 | * There are two other cases, where it's not generally practical | |
494 | * to rely on a single I/O: | |
495 | * | |
496 | * - R1B responses need at least N(EC) bytes of all-zeroes. | |
497 | * | |
498 | * In this case we can *try* to fit it into one I/O, then | |
499 | * maybe read more data later. | |
500 | * | |
501 | * - Data block reads are more troublesome, since a variable | |
502 | * number of padding bytes precede the token and data. | |
503 | * + N(CX) (== 0..8) bytes of all-ones, before CSD or CID | |
504 | * + N(AC) (== 1..many) bytes of all-ones | |
505 | * | |
506 | * In this case we currently only have minimal speedups here: | |
507 | * when N(CR) == 1 we can avoid I/O in response_get(). | |
508 | */ | |
509 | if (cs_on && (mrq->data->flags & MMC_DATA_READ)) { | |
510 | cp += 2; /* min(N(CR)) + status */ | |
511 | /* R1 */ | |
512 | } else { | |
513 | cp += 10; /* max(N(CR)) + status + min(N(RC),N(WR)) */ | |
514 | if (cmd->flags & MMC_RSP_SPI_S2) /* R2/R5 */ | |
515 | cp++; | |
516 | else if (cmd->flags & MMC_RSP_SPI_B4) /* R3/R4/R7 */ | |
517 | cp += 4; | |
518 | else if (cmd->flags & MMC_RSP_BUSY) /* R1B */ | |
519 | cp = data->status + sizeof(data->status); | |
520 | /* else: R1 (most commands) */ | |
521 | } | |
522 | ||
523 | dev_dbg(&host->spi->dev, " mmc_spi: CMD%d, resp %s\n", | |
524 | cmd->opcode, maptype(cmd)); | |
525 | ||
526 | /* send command, leaving chipselect active */ | |
527 | spi_message_init(&host->m); | |
528 | ||
529 | t = &host->t; | |
530 | memset(t, 0, sizeof(*t)); | |
531 | t->tx_buf = t->rx_buf = data->status; | |
532 | t->tx_dma = t->rx_dma = host->data_dma; | |
533 | t->len = cp - data->status; | |
534 | t->cs_change = 1; | |
535 | spi_message_add_tail(t, &host->m); | |
536 | ||
537 | if (host->dma_dev) { | |
538 | host->m.is_dma_mapped = 1; | |
539 | dma_sync_single_for_device(host->dma_dev, | |
540 | host->data_dma, sizeof(*host->data), | |
541 | DMA_BIDIRECTIONAL); | |
542 | } | |
543 | status = spi_sync_locked(host->spi, &host->m); | |
544 | ||
545 | if (host->dma_dev) | |
546 | dma_sync_single_for_cpu(host->dma_dev, | |
547 | host->data_dma, sizeof(*host->data), | |
548 | DMA_BIDIRECTIONAL); | |
549 | if (status < 0) { | |
550 | dev_dbg(&host->spi->dev, " ... write returned %d\n", status); | |
551 | cmd->error = status; | |
552 | return status; | |
553 | } | |
554 | ||
555 | /* after no-data commands and STOP_TRANSMISSION, chipselect off */ | |
556 | return mmc_spi_response_get(host, cmd, cs_on); | |
557 | } | |
558 | ||
559 | /* Build data message with up to four separate transfers. For TX, we | |
560 | * start by writing the data token. And in most cases, we finish with | |
561 | * a status transfer. | |
562 | * | |
563 | * We always provide TX data for data and CRC. The MMC/SD protocol | |
564 | * requires us to write ones; but Linux defaults to writing zeroes; | |
565 | * so we explicitly initialize it to all ones on RX paths. | |
566 | * | |
567 | * We also handle DMA mapping, so the underlying SPI controller does | |
568 | * not need to (re)do it for each message. | |
569 | */ | |
570 | static void | |
571 | mmc_spi_setup_data_message( | |
572 | struct mmc_spi_host *host, | |
573 | int multiple, | |
574 | enum dma_data_direction direction) | |
575 | { | |
576 | struct spi_transfer *t; | |
577 | struct scratch *scratch = host->data; | |
578 | dma_addr_t dma = host->data_dma; | |
579 | ||
580 | spi_message_init(&host->m); | |
581 | if (dma) | |
582 | host->m.is_dma_mapped = 1; | |
583 | ||
584 | /* for reads, readblock() skips 0xff bytes before finding | |
585 | * the token; for writes, this transfer issues that token. | |
586 | */ | |
587 | if (direction == DMA_TO_DEVICE) { | |
588 | t = &host->token; | |
589 | memset(t, 0, sizeof(*t)); | |
590 | t->len = 1; | |
591 | if (multiple) | |
592 | scratch->data_token = SPI_TOKEN_MULTI_WRITE; | |
593 | else | |
594 | scratch->data_token = SPI_TOKEN_SINGLE; | |
595 | t->tx_buf = &scratch->data_token; | |
596 | if (dma) | |
597 | t->tx_dma = dma + offsetof(struct scratch, data_token); | |
598 | spi_message_add_tail(t, &host->m); | |
599 | } | |
600 | ||
601 | /* Body of transfer is buffer, then CRC ... | |
602 | * either TX-only, or RX with TX-ones. | |
603 | */ | |
604 | t = &host->t; | |
605 | memset(t, 0, sizeof(*t)); | |
606 | t->tx_buf = host->ones; | |
607 | t->tx_dma = host->ones_dma; | |
608 | /* length and actual buffer info are written later */ | |
609 | spi_message_add_tail(t, &host->m); | |
610 | ||
611 | t = &host->crc; | |
612 | memset(t, 0, sizeof(*t)); | |
613 | t->len = 2; | |
614 | if (direction == DMA_TO_DEVICE) { | |
615 | /* the actual CRC may get written later */ | |
616 | t->tx_buf = &scratch->crc_val; | |
617 | if (dma) | |
618 | t->tx_dma = dma + offsetof(struct scratch, crc_val); | |
619 | } else { | |
620 | t->tx_buf = host->ones; | |
621 | t->tx_dma = host->ones_dma; | |
622 | t->rx_buf = &scratch->crc_val; | |
623 | if (dma) | |
624 | t->rx_dma = dma + offsetof(struct scratch, crc_val); | |
625 | } | |
626 | spi_message_add_tail(t, &host->m); | |
627 | ||
628 | /* | |
629 | * A single block read is followed by N(EC) [0+] all-ones bytes | |
630 | * before deselect ... don't bother. | |
631 | * | |
632 | * Multiblock reads are followed by N(AC) [1+] all-ones bytes before | |
633 | * the next block is read, or a STOP_TRANSMISSION is issued. We'll | |
634 | * collect that single byte, so readblock() doesn't need to. | |
635 | * | |
636 | * For a write, the one-byte data response follows immediately, then | |
637 | * come zero or more busy bytes, then N(WR) [1+] all-ones bytes. | |
638 | * Then single block reads may deselect, and multiblock ones issue | |
639 | * the next token (next data block, or STOP_TRAN). We can try to | |
640 | * minimize I/O ops by using a single read to collect end-of-busy. | |
641 | */ | |
642 | if (multiple || direction == DMA_TO_DEVICE) { | |
643 | t = &host->early_status; | |
644 | memset(t, 0, sizeof(*t)); | |
645 | t->len = (direction == DMA_TO_DEVICE) | |
646 | ? sizeof(scratch->status) | |
647 | : 1; | |
648 | t->tx_buf = host->ones; | |
649 | t->tx_dma = host->ones_dma; | |
650 | t->rx_buf = scratch->status; | |
651 | if (dma) | |
652 | t->rx_dma = dma + offsetof(struct scratch, status); | |
653 | t->cs_change = 1; | |
654 | spi_message_add_tail(t, &host->m); | |
655 | } | |
656 | } | |
657 | ||
658 | /* | |
659 | * Write one block: | |
660 | * - caller handled preceding N(WR) [1+] all-ones bytes | |
661 | * - data block | |
662 | * + token | |
663 | * + data bytes | |
664 | * + crc16 | |
665 | * - an all-ones byte ... card writes a data-response byte | |
666 | * - followed by N(EC) [0+] all-ones bytes, card writes zero/'busy' | |
667 | * | |
668 | * Return negative errno, else success. | |
669 | */ | |
670 | static int | |
671 | mmc_spi_writeblock(struct mmc_spi_host *host, struct spi_transfer *t, | |
672 | unsigned long timeout) | |
673 | { | |
674 | struct spi_device *spi = host->spi; | |
675 | int status, i; | |
676 | struct scratch *scratch = host->data; | |
677 | u32 pattern; | |
678 | ||
679 | if (host->mmc->use_spi_crc) | |
680 | scratch->crc_val = cpu_to_be16( | |
681 | crc_itu_t(0, t->tx_buf, t->len)); | |
682 | if (host->dma_dev) | |
683 | dma_sync_single_for_device(host->dma_dev, | |
684 | host->data_dma, sizeof(*scratch), | |
685 | DMA_BIDIRECTIONAL); | |
686 | ||
687 | status = spi_sync_locked(spi, &host->m); | |
688 | ||
689 | if (status != 0) { | |
690 | dev_dbg(&spi->dev, "write error (%d)\n", status); | |
691 | return status; | |
692 | } | |
693 | ||
694 | if (host->dma_dev) | |
695 | dma_sync_single_for_cpu(host->dma_dev, | |
696 | host->data_dma, sizeof(*scratch), | |
697 | DMA_BIDIRECTIONAL); | |
698 | ||
699 | /* | |
700 | * Get the transmission data-response reply. It must follow | |
701 | * immediately after the data block we transferred. This reply | |
702 | * doesn't necessarily tell whether the write operation succeeded; | |
703 | * it just says if the transmission was ok and whether *earlier* | |
704 | * writes succeeded; see the standard. | |
705 | * | |
706 | * In practice, there are (even modern SDHC-)cards which are late | |
707 | * in sending the response, and miss the time frame by a few bits, | |
708 | * so we have to cope with this situation and check the response | |
709 | * bit-by-bit. Arggh!!! | |
710 | */ | |
711 | pattern = get_unaligned_be32(scratch->status); | |
712 | ||
713 | /* First 3 bit of pattern are undefined */ | |
714 | pattern |= 0xE0000000; | |
715 | ||
716 | /* left-adjust to leading 0 bit */ | |
717 | while (pattern & 0x80000000) | |
718 | pattern <<= 1; | |
719 | /* right-adjust for pattern matching. Code is in bit 4..0 now. */ | |
720 | pattern >>= 27; | |
721 | ||
722 | switch (pattern) { | |
723 | case SPI_RESPONSE_ACCEPTED: | |
724 | status = 0; | |
725 | break; | |
726 | case SPI_RESPONSE_CRC_ERR: | |
727 | /* host shall then issue MMC_STOP_TRANSMISSION */ | |
728 | status = -EILSEQ; | |
729 | break; | |
730 | case SPI_RESPONSE_WRITE_ERR: | |
731 | /* host shall then issue MMC_STOP_TRANSMISSION, | |
732 | * and should MMC_SEND_STATUS to sort it out | |
733 | */ | |
734 | status = -EIO; | |
735 | break; | |
736 | default: | |
737 | status = -EPROTO; | |
738 | break; | |
739 | } | |
740 | if (status != 0) { | |
741 | dev_dbg(&spi->dev, "write error %02x (%d)\n", | |
742 | scratch->status[0], status); | |
743 | return status; | |
744 | } | |
745 | ||
746 | t->tx_buf += t->len; | |
747 | if (host->dma_dev) | |
748 | t->tx_dma += t->len; | |
749 | ||
750 | /* Return when not busy. If we didn't collect that status yet, | |
751 | * we'll need some more I/O. | |
752 | */ | |
753 | for (i = 4; i < sizeof(scratch->status); i++) { | |
754 | /* card is non-busy if the most recent bit is 1 */ | |
755 | if (scratch->status[i] & 0x01) | |
756 | return 0; | |
757 | } | |
758 | return mmc_spi_wait_unbusy(host, timeout); | |
759 | } | |
760 | ||
761 | /* | |
762 | * Read one block: | |
763 | * - skip leading all-ones bytes ... either | |
764 | * + N(AC) [1..f(clock,CSD)] usually, else | |
765 | * + N(CX) [0..8] when reading CSD or CID | |
766 | * - data block | |
767 | * + token ... if error token, no data or crc | |
768 | * + data bytes | |
769 | * + crc16 | |
770 | * | |
771 | * After single block reads, we're done; N(EC) [0+] all-ones bytes follow | |
772 | * before dropping chipselect. | |
773 | * | |
774 | * For multiblock reads, caller either reads the next block or issues a | |
775 | * STOP_TRANSMISSION command. | |
776 | */ | |
777 | static int | |
778 | mmc_spi_readblock(struct mmc_spi_host *host, struct spi_transfer *t, | |
779 | unsigned long timeout) | |
780 | { | |
781 | struct spi_device *spi = host->spi; | |
782 | int status; | |
783 | struct scratch *scratch = host->data; | |
784 | unsigned int bitshift; | |
785 | u8 leftover; | |
786 | ||
787 | /* At least one SD card sends an all-zeroes byte when N(CX) | |
788 | * applies, before the all-ones bytes ... just cope with that. | |
789 | */ | |
790 | status = mmc_spi_readbytes(host, 1); | |
791 | if (status < 0) | |
792 | return status; | |
793 | status = scratch->status[0]; | |
794 | if (status == 0xff || status == 0) | |
795 | status = mmc_spi_readtoken(host, timeout); | |
796 | ||
797 | if (status < 0) { | |
798 | dev_dbg(&spi->dev, "read error %02x (%d)\n", status, status); | |
799 | return status; | |
800 | } | |
801 | ||
802 | /* The token may be bit-shifted... | |
803 | * the first 0-bit precedes the data stream. | |
804 | */ | |
805 | bitshift = 7; | |
806 | while (status & 0x80) { | |
807 | status <<= 1; | |
808 | bitshift--; | |
809 | } | |
810 | leftover = status << 1; | |
811 | ||
812 | if (host->dma_dev) { | |
813 | dma_sync_single_for_device(host->dma_dev, | |
814 | host->data_dma, sizeof(*scratch), | |
815 | DMA_BIDIRECTIONAL); | |
816 | dma_sync_single_for_device(host->dma_dev, | |
817 | t->rx_dma, t->len, | |
818 | DMA_FROM_DEVICE); | |
819 | } | |
820 | ||
821 | status = spi_sync_locked(spi, &host->m); | |
822 | ||
823 | if (host->dma_dev) { | |
824 | dma_sync_single_for_cpu(host->dma_dev, | |
825 | host->data_dma, sizeof(*scratch), | |
826 | DMA_BIDIRECTIONAL); | |
827 | dma_sync_single_for_cpu(host->dma_dev, | |
828 | t->rx_dma, t->len, | |
829 | DMA_FROM_DEVICE); | |
830 | } | |
831 | ||
832 | if (bitshift) { | |
833 | /* Walk through the data and the crc and do | |
834 | * all the magic to get byte-aligned data. | |
835 | */ | |
836 | u8 *cp = t->rx_buf; | |
837 | unsigned int len; | |
838 | unsigned int bitright = 8 - bitshift; | |
839 | u8 temp; | |
840 | for (len = t->len; len; len--) { | |
841 | temp = *cp; | |
842 | *cp++ = leftover | (temp >> bitshift); | |
843 | leftover = temp << bitright; | |
844 | } | |
845 | cp = (u8 *) &scratch->crc_val; | |
846 | temp = *cp; | |
847 | *cp++ = leftover | (temp >> bitshift); | |
848 | leftover = temp << bitright; | |
849 | temp = *cp; | |
850 | *cp = leftover | (temp >> bitshift); | |
851 | } | |
852 | ||
853 | if (host->mmc->use_spi_crc) { | |
854 | u16 crc = crc_itu_t(0, t->rx_buf, t->len); | |
855 | ||
856 | be16_to_cpus(&scratch->crc_val); | |
857 | if (scratch->crc_val != crc) { | |
858 | dev_dbg(&spi->dev, "read - crc error: crc_val=0x%04x, " | |
859 | "computed=0x%04x len=%d\n", | |
860 | scratch->crc_val, crc, t->len); | |
861 | return -EILSEQ; | |
862 | } | |
863 | } | |
864 | ||
865 | t->rx_buf += t->len; | |
866 | if (host->dma_dev) | |
867 | t->rx_dma += t->len; | |
868 | ||
869 | return 0; | |
870 | } | |
871 | ||
872 | /* | |
873 | * An MMC/SD data stage includes one or more blocks, optional CRCs, | |
874 | * and inline handshaking. That handhaking makes it unlike most | |
875 | * other SPI protocol stacks. | |
876 | */ | |
877 | static void | |
878 | mmc_spi_data_do(struct mmc_spi_host *host, struct mmc_command *cmd, | |
879 | struct mmc_data *data, u32 blk_size) | |
880 | { | |
881 | struct spi_device *spi = host->spi; | |
882 | struct device *dma_dev = host->dma_dev; | |
883 | struct spi_transfer *t; | |
884 | enum dma_data_direction direction; | |
885 | struct scatterlist *sg; | |
886 | unsigned n_sg; | |
887 | int multiple = (data->blocks > 1); | |
888 | u32 clock_rate; | |
889 | unsigned long timeout; | |
890 | ||
891 | direction = mmc_get_dma_dir(data); | |
892 | mmc_spi_setup_data_message(host, multiple, direction); | |
893 | t = &host->t; | |
894 | ||
895 | if (t->speed_hz) | |
896 | clock_rate = t->speed_hz; | |
897 | else | |
898 | clock_rate = spi->max_speed_hz; | |
899 | ||
900 | timeout = data->timeout_ns + | |
901 | data->timeout_clks * 1000000 / clock_rate; | |
902 | timeout = usecs_to_jiffies((unsigned int)(timeout / 1000)) + 1; | |
903 | ||
904 | /* Handle scatterlist segments one at a time, with synch for | |
905 | * each 512-byte block | |
906 | */ | |
907 | for (sg = data->sg, n_sg = data->sg_len; n_sg; n_sg--, sg++) { | |
908 | int status = 0; | |
909 | dma_addr_t dma_addr = 0; | |
910 | void *kmap_addr; | |
911 | unsigned length = sg->length; | |
912 | enum dma_data_direction dir = direction; | |
913 | ||
914 | /* set up dma mapping for controller drivers that might | |
915 | * use DMA ... though they may fall back to PIO | |
916 | */ | |
917 | if (dma_dev) { | |
918 | /* never invalidate whole *shared* pages ... */ | |
919 | if ((sg->offset != 0 || length != PAGE_SIZE) | |
920 | && dir == DMA_FROM_DEVICE) | |
921 | dir = DMA_BIDIRECTIONAL; | |
922 | ||
923 | dma_addr = dma_map_page(dma_dev, sg_page(sg), 0, | |
924 | PAGE_SIZE, dir); | |
925 | if (dma_mapping_error(dma_dev, dma_addr)) { | |
926 | data->error = -EFAULT; | |
927 | break; | |
928 | } | |
929 | if (direction == DMA_TO_DEVICE) | |
930 | t->tx_dma = dma_addr + sg->offset; | |
931 | else | |
932 | t->rx_dma = dma_addr + sg->offset; | |
933 | } | |
934 | ||
935 | /* allow pio too; we don't allow highmem */ | |
936 | kmap_addr = kmap(sg_page(sg)); | |
937 | if (direction == DMA_TO_DEVICE) | |
938 | t->tx_buf = kmap_addr + sg->offset; | |
939 | else | |
940 | t->rx_buf = kmap_addr + sg->offset; | |
941 | ||
942 | /* transfer each block, and update request status */ | |
943 | while (length) { | |
944 | t->len = min(length, blk_size); | |
945 | ||
946 | dev_dbg(&host->spi->dev, | |
947 | " mmc_spi: %s block, %d bytes\n", | |
948 | (direction == DMA_TO_DEVICE) | |
949 | ? "write" | |
950 | : "read", | |
951 | t->len); | |
952 | ||
953 | if (direction == DMA_TO_DEVICE) | |
954 | status = mmc_spi_writeblock(host, t, timeout); | |
955 | else | |
956 | status = mmc_spi_readblock(host, t, timeout); | |
957 | if (status < 0) | |
958 | break; | |
959 | ||
960 | data->bytes_xfered += t->len; | |
961 | length -= t->len; | |
962 | ||
963 | if (!multiple) | |
964 | break; | |
965 | } | |
966 | ||
967 | /* discard mappings */ | |
968 | if (direction == DMA_FROM_DEVICE) | |
969 | flush_kernel_dcache_page(sg_page(sg)); | |
970 | kunmap(sg_page(sg)); | |
971 | if (dma_dev) | |
972 | dma_unmap_page(dma_dev, dma_addr, PAGE_SIZE, dir); | |
973 | ||
974 | if (status < 0) { | |
975 | data->error = status; | |
976 | dev_dbg(&spi->dev, "%s status %d\n", | |
977 | (direction == DMA_TO_DEVICE) | |
978 | ? "write" : "read", | |
979 | status); | |
980 | break; | |
981 | } | |
982 | } | |
983 | ||
984 | /* NOTE some docs describe an MMC-only SET_BLOCK_COUNT (CMD23) that | |
985 | * can be issued before multiblock writes. Unlike its more widely | |
986 | * documented analogue for SD cards (SET_WR_BLK_ERASE_COUNT, ACMD23), | |
987 | * that can affect the STOP_TRAN logic. Complete (and current) | |
988 | * MMC specs should sort that out before Linux starts using CMD23. | |
989 | */ | |
990 | if (direction == DMA_TO_DEVICE && multiple) { | |
991 | struct scratch *scratch = host->data; | |
992 | int tmp; | |
993 | const unsigned statlen = sizeof(scratch->status); | |
994 | ||
995 | dev_dbg(&spi->dev, " mmc_spi: STOP_TRAN\n"); | |
996 | ||
997 | /* Tweak the per-block message we set up earlier by morphing | |
998 | * it to hold single buffer with the token followed by some | |
999 | * all-ones bytes ... skip N(BR) (0..1), scan the rest for | |
1000 | * "not busy any longer" status, and leave chip selected. | |
1001 | */ | |
1002 | INIT_LIST_HEAD(&host->m.transfers); | |
1003 | list_add(&host->early_status.transfer_list, | |
1004 | &host->m.transfers); | |
1005 | ||
1006 | memset(scratch->status, 0xff, statlen); | |
1007 | scratch->status[0] = SPI_TOKEN_STOP_TRAN; | |
1008 | ||
1009 | host->early_status.tx_buf = host->early_status.rx_buf; | |
1010 | host->early_status.tx_dma = host->early_status.rx_dma; | |
1011 | host->early_status.len = statlen; | |
1012 | ||
1013 | if (host->dma_dev) | |
1014 | dma_sync_single_for_device(host->dma_dev, | |
1015 | host->data_dma, sizeof(*scratch), | |
1016 | DMA_BIDIRECTIONAL); | |
1017 | ||
1018 | tmp = spi_sync_locked(spi, &host->m); | |
1019 | ||
1020 | if (host->dma_dev) | |
1021 | dma_sync_single_for_cpu(host->dma_dev, | |
1022 | host->data_dma, sizeof(*scratch), | |
1023 | DMA_BIDIRECTIONAL); | |
1024 | ||
1025 | if (tmp < 0) { | |
1026 | if (!data->error) | |
1027 | data->error = tmp; | |
1028 | return; | |
1029 | } | |
1030 | ||
1031 | /* Ideally we collected "not busy" status with one I/O, | |
1032 | * avoiding wasteful byte-at-a-time scanning... but more | |
1033 | * I/O is often needed. | |
1034 | */ | |
1035 | for (tmp = 2; tmp < statlen; tmp++) { | |
1036 | if (scratch->status[tmp] != 0) | |
1037 | return; | |
1038 | } | |
1039 | tmp = mmc_spi_wait_unbusy(host, timeout); | |
1040 | if (tmp < 0 && !data->error) | |
1041 | data->error = tmp; | |
1042 | } | |
1043 | } | |
1044 | ||
1045 | /****************************************************************************/ | |
1046 | ||
1047 | /* | |
1048 | * MMC driver implementation -- the interface to the MMC stack | |
1049 | */ | |
1050 | ||
1051 | static void mmc_spi_request(struct mmc_host *mmc, struct mmc_request *mrq) | |
1052 | { | |
1053 | struct mmc_spi_host *host = mmc_priv(mmc); | |
1054 | int status = -EINVAL; | |
1055 | int crc_retry = 5; | |
1056 | struct mmc_command stop; | |
1057 | ||
1058 | #ifdef DEBUG | |
1059 | /* MMC core and layered drivers *MUST* issue SPI-aware commands */ | |
1060 | { | |
1061 | struct mmc_command *cmd; | |
1062 | int invalid = 0; | |
1063 | ||
1064 | cmd = mrq->cmd; | |
1065 | if (!mmc_spi_resp_type(cmd)) { | |
1066 | dev_dbg(&host->spi->dev, "bogus command\n"); | |
1067 | cmd->error = -EINVAL; | |
1068 | invalid = 1; | |
1069 | } | |
1070 | ||
1071 | cmd = mrq->stop; | |
1072 | if (cmd && !mmc_spi_resp_type(cmd)) { | |
1073 | dev_dbg(&host->spi->dev, "bogus STOP command\n"); | |
1074 | cmd->error = -EINVAL; | |
1075 | invalid = 1; | |
1076 | } | |
1077 | ||
1078 | if (invalid) { | |
1079 | dump_stack(); | |
1080 | mmc_request_done(host->mmc, mrq); | |
1081 | return; | |
1082 | } | |
1083 | } | |
1084 | #endif | |
1085 | ||
1086 | /* request exclusive bus access */ | |
1087 | spi_bus_lock(host->spi->master); | |
1088 | ||
1089 | crc_recover: | |
1090 | /* issue command; then optionally data and stop */ | |
1091 | status = mmc_spi_command_send(host, mrq, mrq->cmd, mrq->data != NULL); | |
1092 | if (status == 0 && mrq->data) { | |
1093 | mmc_spi_data_do(host, mrq->cmd, mrq->data, mrq->data->blksz); | |
1094 | ||
1095 | /* | |
1096 | * The SPI bus is not always reliable for large data transfers. | |
1097 | * If an occasional crc error is reported by the SD device with | |
1098 | * data read/write over SPI, it may be recovered by repeating | |
1099 | * the last SD command again. The retry count is set to 5 to | |
1100 | * ensure the driver passes stress tests. | |
1101 | */ | |
1102 | if (mrq->data->error == -EILSEQ && crc_retry) { | |
1103 | stop.opcode = MMC_STOP_TRANSMISSION; | |
1104 | stop.arg = 0; | |
1105 | stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC; | |
1106 | status = mmc_spi_command_send(host, mrq, &stop, 0); | |
1107 | crc_retry--; | |
1108 | mrq->data->error = 0; | |
1109 | goto crc_recover; | |
1110 | } | |
1111 | ||
1112 | if (mrq->stop) | |
1113 | status = mmc_spi_command_send(host, mrq, mrq->stop, 0); | |
1114 | else | |
1115 | mmc_cs_off(host); | |
1116 | } | |
1117 | ||
1118 | /* release the bus */ | |
1119 | spi_bus_unlock(host->spi->master); | |
1120 | ||
1121 | mmc_request_done(host->mmc, mrq); | |
1122 | } | |
1123 | ||
1124 | /* See Section 6.4.1, in SD "Simplified Physical Layer Specification 2.0" | |
1125 | * | |
1126 | * NOTE that here we can't know that the card has just been powered up; | |
1127 | * not all MMC/SD sockets support power switching. | |
1128 | * | |
1129 | * FIXME when the card is still in SPI mode, e.g. from a previous kernel, | |
1130 | * this doesn't seem to do the right thing at all... | |
1131 | */ | |
1132 | static void mmc_spi_initsequence(struct mmc_spi_host *host) | |
1133 | { | |
1134 | /* Try to be very sure any previous command has completed; | |
1135 | * wait till not-busy, skip debris from any old commands. | |
1136 | */ | |
1137 | mmc_spi_wait_unbusy(host, r1b_timeout); | |
1138 | mmc_spi_readbytes(host, 10); | |
1139 | ||
1140 | /* | |
1141 | * Do a burst with chipselect active-high. We need to do this to | |
1142 | * meet the requirement of 74 clock cycles with both chipselect | |
1143 | * and CMD (MOSI) high before CMD0 ... after the card has been | |
1144 | * powered up to Vdd(min), and so is ready to take commands. | |
1145 | * | |
1146 | * Some cards are particularly needy of this (e.g. Viking "SD256") | |
1147 | * while most others don't seem to care. | |
1148 | * | |
1149 | * Note that this is one of the places MMC/SD plays games with the | |
1150 | * SPI protocol. Another is that when chipselect is released while | |
1151 | * the card returns BUSY status, the clock must issue several cycles | |
1152 | * with chipselect high before the card will stop driving its output. | |
1153 | */ | |
1154 | host->spi->mode |= SPI_CS_HIGH; | |
1155 | if (spi_setup(host->spi) != 0) { | |
1156 | /* Just warn; most cards work without it. */ | |
1157 | dev_warn(&host->spi->dev, | |
1158 | "can't change chip-select polarity\n"); | |
1159 | host->spi->mode &= ~SPI_CS_HIGH; | |
1160 | } else { | |
1161 | mmc_spi_readbytes(host, 18); | |
1162 | ||
1163 | host->spi->mode &= ~SPI_CS_HIGH; | |
1164 | if (spi_setup(host->spi) != 0) { | |
1165 | /* Wot, we can't get the same setup we had before? */ | |
1166 | dev_err(&host->spi->dev, | |
1167 | "can't restore chip-select polarity\n"); | |
1168 | } | |
1169 | } | |
1170 | } | |
1171 | ||
1172 | static char *mmc_powerstring(u8 power_mode) | |
1173 | { | |
1174 | switch (power_mode) { | |
1175 | case MMC_POWER_OFF: return "off"; | |
1176 | case MMC_POWER_UP: return "up"; | |
1177 | case MMC_POWER_ON: return "on"; | |
1178 | } | |
1179 | return "?"; | |
1180 | } | |
1181 | ||
1182 | static void mmc_spi_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) | |
1183 | { | |
1184 | struct mmc_spi_host *host = mmc_priv(mmc); | |
1185 | ||
1186 | if (host->power_mode != ios->power_mode) { | |
1187 | int canpower; | |
1188 | ||
1189 | canpower = host->pdata && host->pdata->setpower; | |
1190 | ||
1191 | dev_dbg(&host->spi->dev, "mmc_spi: power %s (%d)%s\n", | |
1192 | mmc_powerstring(ios->power_mode), | |
1193 | ios->vdd, | |
1194 | canpower ? ", can switch" : ""); | |
1195 | ||
1196 | /* switch power on/off if possible, accounting for | |
1197 | * max 250msec powerup time if needed. | |
1198 | */ | |
1199 | if (canpower) { | |
1200 | switch (ios->power_mode) { | |
1201 | case MMC_POWER_OFF: | |
1202 | case MMC_POWER_UP: | |
1203 | host->pdata->setpower(&host->spi->dev, | |
1204 | ios->vdd); | |
1205 | if (ios->power_mode == MMC_POWER_UP) | |
1206 | msleep(host->powerup_msecs); | |
1207 | } | |
1208 | } | |
1209 | ||
1210 | /* See 6.4.1 in the simplified SD card physical spec 2.0 */ | |
1211 | if (ios->power_mode == MMC_POWER_ON) | |
1212 | mmc_spi_initsequence(host); | |
1213 | ||
1214 | /* If powering down, ground all card inputs to avoid power | |
1215 | * delivery from data lines! On a shared SPI bus, this | |
1216 | * will probably be temporary; 6.4.2 of the simplified SD | |
1217 | * spec says this must last at least 1msec. | |
1218 | * | |
1219 | * - Clock low means CPOL 0, e.g. mode 0 | |
1220 | * - MOSI low comes from writing zero | |
1221 | * - Chipselect is usually active low... | |
1222 | */ | |
1223 | if (canpower && ios->power_mode == MMC_POWER_OFF) { | |
1224 | int mres; | |
1225 | u8 nullbyte = 0; | |
1226 | ||
1227 | host->spi->mode &= ~(SPI_CPOL|SPI_CPHA); | |
1228 | mres = spi_setup(host->spi); | |
1229 | if (mres < 0) | |
1230 | dev_dbg(&host->spi->dev, | |
1231 | "switch to SPI mode 0 failed\n"); | |
1232 | ||
1233 | if (spi_write(host->spi, &nullbyte, 1) < 0) | |
1234 | dev_dbg(&host->spi->dev, | |
1235 | "put spi signals to low failed\n"); | |
1236 | ||
1237 | /* | |
1238 | * Now clock should be low due to spi mode 0; | |
1239 | * MOSI should be low because of written 0x00; | |
1240 | * chipselect should be low (it is active low) | |
1241 | * power supply is off, so now MMC is off too! | |
1242 | * | |
1243 | * FIXME no, chipselect can be high since the | |
1244 | * device is inactive and SPI_CS_HIGH is clear... | |
1245 | */ | |
1246 | msleep(10); | |
1247 | if (mres == 0) { | |
1248 | host->spi->mode |= (SPI_CPOL|SPI_CPHA); | |
1249 | mres = spi_setup(host->spi); | |
1250 | if (mres < 0) | |
1251 | dev_dbg(&host->spi->dev, | |
1252 | "switch back to SPI mode 3" | |
1253 | " failed\n"); | |
1254 | } | |
1255 | } | |
1256 | ||
1257 | host->power_mode = ios->power_mode; | |
1258 | } | |
1259 | ||
1260 | if (host->spi->max_speed_hz != ios->clock && ios->clock != 0) { | |
1261 | int status; | |
1262 | ||
1263 | host->spi->max_speed_hz = ios->clock; | |
1264 | status = spi_setup(host->spi); | |
1265 | dev_dbg(&host->spi->dev, | |
1266 | "mmc_spi: clock to %d Hz, %d\n", | |
1267 | host->spi->max_speed_hz, status); | |
1268 | } | |
1269 | } | |
1270 | ||
1271 | static const struct mmc_host_ops mmc_spi_ops = { | |
1272 | .request = mmc_spi_request, | |
1273 | .set_ios = mmc_spi_set_ios, | |
1274 | .get_ro = mmc_gpio_get_ro, | |
1275 | .get_cd = mmc_gpio_get_cd, | |
1276 | }; | |
1277 | ||
1278 | ||
1279 | /****************************************************************************/ | |
1280 | ||
1281 | /* | |
1282 | * SPI driver implementation | |
1283 | */ | |
1284 | ||
1285 | static irqreturn_t | |
1286 | mmc_spi_detect_irq(int irq, void *mmc) | |
1287 | { | |
1288 | struct mmc_spi_host *host = mmc_priv(mmc); | |
1289 | u16 delay_msec = max(host->pdata->detect_delay, (u16)100); | |
1290 | ||
1291 | mmc_detect_change(mmc, msecs_to_jiffies(delay_msec)); | |
1292 | return IRQ_HANDLED; | |
1293 | } | |
1294 | ||
1295 | static int mmc_spi_probe(struct spi_device *spi) | |
1296 | { | |
1297 | void *ones; | |
1298 | struct mmc_host *mmc; | |
1299 | struct mmc_spi_host *host; | |
1300 | int status; | |
1301 | bool has_ro = false; | |
1302 | ||
1303 | /* We rely on full duplex transfers, mostly to reduce | |
1304 | * per-transfer overheads (by making fewer transfers). | |
1305 | */ | |
1306 | if (spi->master->flags & SPI_MASTER_HALF_DUPLEX) | |
1307 | return -EINVAL; | |
1308 | ||
1309 | /* MMC and SD specs only seem to care that sampling is on the | |
1310 | * rising edge ... meaning SPI modes 0 or 3. So either SPI mode | |
1311 | * should be legit. We'll use mode 0 since the steady state is 0, | |
1312 | * which is appropriate for hotplugging, unless the platform data | |
1313 | * specify mode 3 (if hardware is not compatible to mode 0). | |
1314 | */ | |
1315 | if (spi->mode != SPI_MODE_3) | |
1316 | spi->mode = SPI_MODE_0; | |
1317 | spi->bits_per_word = 8; | |
1318 | ||
1319 | status = spi_setup(spi); | |
1320 | if (status < 0) { | |
1321 | dev_dbg(&spi->dev, "needs SPI mode %02x, %d KHz; %d\n", | |
1322 | spi->mode, spi->max_speed_hz / 1000, | |
1323 | status); | |
1324 | return status; | |
1325 | } | |
1326 | ||
1327 | /* We need a supply of ones to transmit. This is the only time | |
1328 | * the CPU touches these, so cache coherency isn't a concern. | |
1329 | * | |
1330 | * NOTE if many systems use more than one MMC-over-SPI connector | |
1331 | * it'd save some memory to share this. That's evidently rare. | |
1332 | */ | |
1333 | status = -ENOMEM; | |
1334 | ones = kmalloc(MMC_SPI_BLOCKSIZE, GFP_KERNEL); | |
1335 | if (!ones) | |
1336 | goto nomem; | |
1337 | memset(ones, 0xff, MMC_SPI_BLOCKSIZE); | |
1338 | ||
1339 | mmc = mmc_alloc_host(sizeof(*host), &spi->dev); | |
1340 | if (!mmc) | |
1341 | goto nomem; | |
1342 | ||
1343 | mmc->ops = &mmc_spi_ops; | |
1344 | mmc->max_blk_size = MMC_SPI_BLOCKSIZE; | |
1345 | mmc->max_segs = MMC_SPI_BLOCKSATONCE; | |
1346 | mmc->max_req_size = MMC_SPI_BLOCKSATONCE * MMC_SPI_BLOCKSIZE; | |
1347 | mmc->max_blk_count = MMC_SPI_BLOCKSATONCE; | |
1348 | ||
1349 | mmc->caps = MMC_CAP_SPI; | |
1350 | ||
1351 | /* SPI doesn't need the lowspeed device identification thing for | |
1352 | * MMC or SD cards, since it never comes up in open drain mode. | |
1353 | * That's good; some SPI masters can't handle very low speeds! | |
1354 | * | |
1355 | * However, low speed SDIO cards need not handle over 400 KHz; | |
1356 | * that's the only reason not to use a few MHz for f_min (until | |
1357 | * the upper layer reads the target frequency from the CSD). | |
1358 | */ | |
1359 | mmc->f_min = 400000; | |
1360 | mmc->f_max = spi->max_speed_hz; | |
1361 | ||
1362 | host = mmc_priv(mmc); | |
1363 | host->mmc = mmc; | |
1364 | host->spi = spi; | |
1365 | ||
1366 | host->ones = ones; | |
1367 | ||
1368 | /* Platform data is used to hook up things like card sensing | |
1369 | * and power switching gpios. | |
1370 | */ | |
1371 | host->pdata = mmc_spi_get_pdata(spi); | |
1372 | if (host->pdata) | |
1373 | mmc->ocr_avail = host->pdata->ocr_mask; | |
1374 | if (!mmc->ocr_avail) { | |
1375 | dev_warn(&spi->dev, "ASSUMING 3.2-3.4 V slot power\n"); | |
1376 | mmc->ocr_avail = MMC_VDD_32_33|MMC_VDD_33_34; | |
1377 | } | |
1378 | if (host->pdata && host->pdata->setpower) { | |
1379 | host->powerup_msecs = host->pdata->powerup_msecs; | |
1380 | if (!host->powerup_msecs || host->powerup_msecs > 250) | |
1381 | host->powerup_msecs = 250; | |
1382 | } | |
1383 | ||
1384 | dev_set_drvdata(&spi->dev, mmc); | |
1385 | ||
1386 | /* preallocate dma buffers */ | |
1387 | host->data = kmalloc(sizeof(*host->data), GFP_KERNEL); | |
1388 | if (!host->data) | |
1389 | goto fail_nobuf1; | |
1390 | ||
1391 | if (spi->master->dev.parent->dma_mask) { | |
1392 | struct device *dev = spi->master->dev.parent; | |
1393 | ||
1394 | host->dma_dev = dev; | |
1395 | host->ones_dma = dma_map_single(dev, ones, | |
1396 | MMC_SPI_BLOCKSIZE, DMA_TO_DEVICE); | |
1397 | if (dma_mapping_error(dev, host->ones_dma)) | |
1398 | goto fail_ones_dma; | |
1399 | host->data_dma = dma_map_single(dev, host->data, | |
1400 | sizeof(*host->data), DMA_BIDIRECTIONAL); | |
1401 | if (dma_mapping_error(dev, host->data_dma)) | |
1402 | goto fail_data_dma; | |
1403 | ||
1404 | dma_sync_single_for_cpu(host->dma_dev, | |
1405 | host->data_dma, sizeof(*host->data), | |
1406 | DMA_BIDIRECTIONAL); | |
1407 | } | |
1408 | ||
1409 | /* setup message for status/busy readback */ | |
1410 | spi_message_init(&host->readback); | |
1411 | host->readback.is_dma_mapped = (host->dma_dev != NULL); | |
1412 | ||
1413 | spi_message_add_tail(&host->status, &host->readback); | |
1414 | host->status.tx_buf = host->ones; | |
1415 | host->status.tx_dma = host->ones_dma; | |
1416 | host->status.rx_buf = &host->data->status; | |
1417 | host->status.rx_dma = host->data_dma + offsetof(struct scratch, status); | |
1418 | host->status.cs_change = 1; | |
1419 | ||
1420 | /* register card detect irq */ | |
1421 | if (host->pdata && host->pdata->init) { | |
1422 | status = host->pdata->init(&spi->dev, mmc_spi_detect_irq, mmc); | |
1423 | if (status != 0) | |
1424 | goto fail_glue_init; | |
1425 | } | |
1426 | ||
1427 | /* pass platform capabilities, if any */ | |
1428 | if (host->pdata) { | |
1429 | mmc->caps |= host->pdata->caps; | |
1430 | mmc->caps2 |= host->pdata->caps2; | |
1431 | } | |
1432 | ||
1433 | status = mmc_add_host(mmc); | |
1434 | if (status != 0) | |
1435 | goto fail_add_host; | |
1436 | ||
1437 | if (host->pdata && host->pdata->flags & MMC_SPI_USE_CD_GPIO) { | |
1438 | status = mmc_gpio_request_cd(mmc, host->pdata->cd_gpio, | |
1439 | host->pdata->cd_debounce); | |
1440 | if (status != 0) | |
1441 | goto fail_add_host; | |
1442 | ||
1443 | /* The platform has a CD GPIO signal that may support | |
1444 | * interrupts, so let mmc_gpiod_request_cd_irq() decide | |
1445 | * if polling is needed or not. | |
1446 | */ | |
1447 | mmc->caps &= ~MMC_CAP_NEEDS_POLL; | |
1448 | mmc_gpiod_request_cd_irq(mmc); | |
1449 | } | |
1450 | ||
1451 | if (host->pdata && host->pdata->flags & MMC_SPI_USE_RO_GPIO) { | |
1452 | has_ro = true; | |
1453 | status = mmc_gpio_request_ro(mmc, host->pdata->ro_gpio); | |
1454 | if (status != 0) | |
1455 | goto fail_add_host; | |
1456 | } | |
1457 | ||
1458 | dev_info(&spi->dev, "SD/MMC host %s%s%s%s%s\n", | |
1459 | dev_name(&mmc->class_dev), | |
1460 | host->dma_dev ? "" : ", no DMA", | |
1461 | has_ro ? "" : ", no WP", | |
1462 | (host->pdata && host->pdata->setpower) | |
1463 | ? "" : ", no poweroff", | |
1464 | (mmc->caps & MMC_CAP_NEEDS_POLL) | |
1465 | ? ", cd polling" : ""); | |
1466 | return 0; | |
1467 | ||
1468 | fail_add_host: | |
1469 | mmc_remove_host (mmc); | |
1470 | fail_glue_init: | |
1471 | if (host->dma_dev) | |
1472 | dma_unmap_single(host->dma_dev, host->data_dma, | |
1473 | sizeof(*host->data), DMA_BIDIRECTIONAL); | |
1474 | fail_data_dma: | |
1475 | if (host->dma_dev) | |
1476 | dma_unmap_single(host->dma_dev, host->ones_dma, | |
1477 | MMC_SPI_BLOCKSIZE, DMA_TO_DEVICE); | |
1478 | fail_ones_dma: | |
1479 | kfree(host->data); | |
1480 | ||
1481 | fail_nobuf1: | |
1482 | mmc_free_host(mmc); | |
1483 | mmc_spi_put_pdata(spi); | |
1484 | dev_set_drvdata(&spi->dev, NULL); | |
1485 | ||
1486 | nomem: | |
1487 | kfree(ones); | |
1488 | return status; | |
1489 | } | |
1490 | ||
1491 | ||
1492 | static int mmc_spi_remove(struct spi_device *spi) | |
1493 | { | |
1494 | struct mmc_host *mmc = dev_get_drvdata(&spi->dev); | |
1495 | struct mmc_spi_host *host; | |
1496 | ||
1497 | if (mmc) { | |
1498 | host = mmc_priv(mmc); | |
1499 | ||
1500 | /* prevent new mmc_detect_change() calls */ | |
1501 | if (host->pdata && host->pdata->exit) | |
1502 | host->pdata->exit(&spi->dev, mmc); | |
1503 | ||
1504 | mmc_remove_host(mmc); | |
1505 | ||
1506 | if (host->dma_dev) { | |
1507 | dma_unmap_single(host->dma_dev, host->ones_dma, | |
1508 | MMC_SPI_BLOCKSIZE, DMA_TO_DEVICE); | |
1509 | dma_unmap_single(host->dma_dev, host->data_dma, | |
1510 | sizeof(*host->data), DMA_BIDIRECTIONAL); | |
1511 | } | |
1512 | ||
1513 | kfree(host->data); | |
1514 | kfree(host->ones); | |
1515 | ||
1516 | spi->max_speed_hz = mmc->f_max; | |
1517 | mmc_free_host(mmc); | |
1518 | mmc_spi_put_pdata(spi); | |
1519 | dev_set_drvdata(&spi->dev, NULL); | |
1520 | } | |
1521 | return 0; | |
1522 | } | |
1523 | ||
1524 | static const struct of_device_id mmc_spi_of_match_table[] = { | |
1525 | { .compatible = "mmc-spi-slot", }, | |
1526 | {}, | |
1527 | }; | |
1528 | MODULE_DEVICE_TABLE(of, mmc_spi_of_match_table); | |
1529 | ||
1530 | static struct spi_driver mmc_spi_driver = { | |
1531 | .driver = { | |
1532 | .name = "mmc_spi", | |
1533 | .of_match_table = mmc_spi_of_match_table, | |
1534 | }, | |
1535 | .probe = mmc_spi_probe, | |
1536 | .remove = mmc_spi_remove, | |
1537 | }; | |
1538 | ||
1539 | module_spi_driver(mmc_spi_driver); | |
1540 | ||
1541 | MODULE_AUTHOR("Mike Lavender, David Brownell, " | |
1542 | "Hans-Peter Nilsson, Jan Nikitenko"); | |
1543 | MODULE_DESCRIPTION("SPI SD/MMC host driver"); | |
1544 | MODULE_LICENSE("GPL"); | |
1545 | MODULE_ALIAS("spi:mmc_spi"); |