xref: /freebsd/sys/dev/altera/sdcard/altera_sdcard_io.c (revision f39bffc62c1395bde25d152c7f68fdf7cbaab414)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2012 Robert N. M. Watson
5  * All rights reserved.
6  *
7  * This software was developed by SRI International and the University of
8  * Cambridge Computer Laboratory under DARPA/AFRL contract (FA8750-10-C-0237)
9  * ("CTSRD"), as part of the DARPA CRASH research programme.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include <sys/param.h>
37 #include <sys/bus.h>
38 #include <sys/condvar.h>
39 #include <sys/conf.h>
40 #include <sys/bio.h>
41 #include <sys/endian.h>
42 #include <sys/kernel.h>
43 #include <sys/lock.h>
44 #include <sys/malloc.h>
45 #include <sys/module.h>
46 #include <sys/mutex.h>
47 #include <sys/rman.h>
48 #include <sys/systm.h>
49 #include <sys/taskqueue.h>
50 
51 #include <machine/bus.h>
52 #include <machine/resource.h>
53 
54 #include <geom/geom_disk.h>
55 
56 #include <dev/altera/sdcard/altera_sdcard.h>
57 
58 int altera_sdcard_ignore_crc_errors = 1;
59 int altera_sdcard_verify_rxtx_writes = 1;
60 
61 /*
62  * Low-level I/O routines for the Altera SD Card University IP Core driver.
63  *
64  * XXXRW: Throughout, it is assumed that the IP Core handles multibyte
65  * registers as little endian, as is the case for other Altera IP cores.
66  * However, the specification makes no reference to endianness, so this
67  * assumption might not always be correct.
68  */
69 uint16_t
70 altera_sdcard_read_asr(struct altera_sdcard_softc *sc)
71 {
72 
73 	return (le16toh(bus_read_2(sc->as_res, ALTERA_SDCARD_OFF_ASR)));
74 }
75 
76 static int
77 altera_sdcard_process_csd0(struct altera_sdcard_softc *sc)
78 {
79 	uint64_t c_size, c_size_mult, read_bl_len;
80 	uint8_t byte0, byte1, byte2;
81 
82 	ALTERA_SDCARD_LOCK_ASSERT(sc);
83 
84 	/*-
85 	 * Compute card capacity per SD Card interface description as follows:
86 	 *
87 	 *   Memory capacity = BLOCKNR * BLOCK_LEN
88 	 *
89 	 * Where:
90 	 *
91 	 *   BLOCKNR = (C_SIZE + 1) * MULT
92 	 *   MULT = 2^(C_SIZE_MULT+2)
93 	 *   BLOCK_LEN = 2^READ_BL_LEN
94 	 */
95 	read_bl_len = sc->as_csd.csd_data[ALTERA_SDCARD_CSD_READ_BL_LEN_BYTE];
96 	read_bl_len &= ALTERA_SDCARD_CSD_READ_BL_LEN_MASK;
97 
98 	byte0 = sc->as_csd.csd_data[ALTERA_SDCARD_CSD_C_SIZE_BYTE0];
99 	byte0 &= ALTERA_SDCARD_CSD_C_SIZE_MASK0;
100 	byte1 = sc->as_csd.csd_data[ALTERA_SDCARD_CSD_C_SIZE_BYTE1];
101 	byte2 = sc->as_csd.csd_data[ALTERA_SDCARD_CSD_C_SIZE_BYTE2];
102 	byte2 &= ALTERA_SDCARD_CSD_C_SIZE_MASK2;
103 	c_size = (byte0 >> ALTERA_SDCARD_CSD_C_SIZE_RSHIFT0) |
104 	    (byte1 << ALTERA_SDCARD_CSD_C_SIZE_LSHIFT1) |
105 	    (byte2 << ALTERA_SDCARD_CSD_C_SIZE_LSHIFT2);
106 
107 	byte0 = sc->as_csd.csd_data[ALTERA_SDCARD_CSD_C_SIZE_MULT_BYTE0];
108 	byte0 &= ALTERA_SDCARD_CSD_C_SIZE_MULT_MASK0;
109 	byte1 = sc->as_csd.csd_data[ALTERA_SDCARD_CSD_C_SIZE_MULT_BYTE1];
110 	byte1 &= ALTERA_SDCARD_CSD_C_SIZE_MULT_MASK1;
111 	c_size_mult = (byte0 >> ALTERA_SDCARD_CSD_C_SIZE_MULT_RSHIFT0) |
112 	    (byte1 << ALTERA_SDCARD_CSD_C_SIZE_MULT_LSHIFT1);
113 
114 	/*
115 	 * If we're just getting back zero's, mark the card as bad, even
116 	 * though it could just mean a Very Small Disk Indeed.
117 	 */
118 	if (c_size == 0 && c_size_mult == 0 && read_bl_len == 0) {
119 		device_printf(sc->as_dev, "Ignored zero-size card\n");
120 		return (ENXIO);
121 	}
122 	sc->as_mediasize = (c_size + 1) * (1 << (c_size_mult + 2)) *
123 	    (1 << read_bl_len);
124 	return (0);
125 }
126 
127 int
128 altera_sdcard_read_csd(struct altera_sdcard_softc *sc)
129 {
130 	uint8_t csd_structure;
131 	int error;
132 
133 	ALTERA_SDCARD_LOCK_ASSERT(sc);
134 
135 	/*
136 	 * XXXRW: Assume for now that when the SD Card IP Core negotiates
137 	 * voltage/speed/etc, it must use the CSD register, and therefore
138 	 * populates the SD Card IP Core's cache of the register value.  This
139 	 * means that we can read it without issuing further SD Card commands.
140 	 * If this assumption proves false, we will (a) get back garbage and
141 	 * (b) need to add additional states in the driver state machine in
142 	 * order to query card properties before I/O can start.
143 	 *
144 	 * XXXRW: Treating this as an array of bytes, so no byte swapping --
145 	 * is that a safe assumption?
146 	 */
147 	KASSERT(((uintptr_t)&sc->as_csd.csd_data) % 2 == 0,
148 	    ("%s: CSD buffer unaligned", __func__));
149 	bus_read_region_2(sc->as_res, ALTERA_SDCARD_OFF_CSD,
150 	    (uint16_t *)sc->as_csd.csd_data, sizeof(sc->as_csd) / 2);
151 
152 	/*
153 	 * Interpret the loaded CSD, extracting certain fields and copying
154 	 * them into the softc for easy software access.
155 	 *
156 	 * Currently, we support only CSD Version 1.0.  If we detect a newer
157 	 * version, suppress card detection.
158 	 */
159 	csd_structure = sc->as_csd.csd_data[ALTERA_SDCARD_CSD_STRUCTURE_BYTE];
160 	csd_structure &= ALTERA_SDCARD_CSD_STRUCTURE_MASK;
161 	csd_structure >>= ALTERA_SDCARD_CSD_STRUCTURE_RSHIFT;
162 	sc->as_csd_structure = csd_structure;
163 
164 	/*
165 	 * Interpret the CSD field based on its version.  Extract fields,
166 	 * especially mediasize.
167 	 *
168 	 * XXXRW: Desirable to support further CSD versions here.
169 	 */
170 	switch (sc->as_csd_structure) {
171 	case 0:
172 		error = altera_sdcard_process_csd0(sc);
173 		if (error)
174 			return (error);
175 		break;
176 
177 	default:
178 		device_printf(sc->as_dev,
179 		    "Ignored disk with unsupported CSD structure (%d)\n",
180 		    sc->as_csd_structure);
181 		return (ENXIO);
182 	}
183 	return (0);
184 }
185 
186 /*
187  * XXXRW: The Altera IP Core specification indicates that RR1 is a 16-bit
188  * register, but all bits it identifies are >16 bit.  Most likely, RR1 is a
189  * 32-bit register?
190  */
191 static uint16_t
192 altera_sdcard_read_rr1(struct altera_sdcard_softc *sc)
193 {
194 
195 	return (le16toh(bus_read_2(sc->as_res, ALTERA_SDCARD_OFF_RR1)));
196 }
197 
198 static void
199 altera_sdcard_write_cmd_arg(struct altera_sdcard_softc *sc, uint32_t cmd_arg)
200 {
201 
202 	bus_write_4(sc->as_res, ALTERA_SDCARD_OFF_CMD_ARG, htole32(cmd_arg));
203 }
204 
205 static void
206 altera_sdcard_write_cmd(struct altera_sdcard_softc *sc, uint16_t cmd)
207 {
208 
209 	bus_write_2(sc->as_res, ALTERA_SDCARD_OFF_CMD, htole16(cmd));
210 }
211 
212 static void
213 altera_sdcard_read_rxtx_buffer(struct altera_sdcard_softc *sc, void *data,
214     size_t len)
215 {
216 
217 	KASSERT((uintptr_t)data % 2 == 0,
218 	    ("%s: unaligned data %p", __func__, data));
219 	KASSERT((len <= ALTERA_SDCARD_SECTORSIZE) && (len % 2 == 0),
220 	    ("%s: invalid length %ju", __func__, len));
221 
222 	bus_read_region_2(sc->as_res, ALTERA_SDCARD_OFF_RXTX_BUFFER,
223 	    (uint16_t *)data, len / 2);
224 }
225 
226 static void
227 altera_sdcard_write_rxtx_buffer(struct altera_sdcard_softc *sc, void *data,
228     size_t len)
229 {
230 	u_int corrections, differences, i, retry_counter;
231 	uint16_t d, v;
232 
233 	KASSERT((uintptr_t)data % 2 == 0,
234 	    ("%s: unaligned data %p", __func__, data));
235 	KASSERT((len <= ALTERA_SDCARD_SECTORSIZE) && (len % 2 == 0),
236 	    ("%s: invalid length %ju", __func__, len));
237 
238 	retry_counter = 0;
239 	do {
240 		bus_write_region_2(sc->as_res, ALTERA_SDCARD_OFF_RXTX_BUFFER,
241 		    (uint16_t *)data, len / 2);
242 
243 		/*
244 		 * XXXRW: Due to a possible hardware bug, the above call to
245 		 * bus_write_region_2() might not succeed.  If the workaround
246 		 * is enabled, verify each write and retry until it succeeds.
247 		 *
248 		 * XXXRW: Do we want a limit counter for retries here?
249 		 */
250 recheck:
251 		corrections = 0;
252 		differences = 0;
253 		if (altera_sdcard_verify_rxtx_writes) {
254 			for (i = 0; i < ALTERA_SDCARD_SECTORSIZE; i += 2) {
255 				v = bus_read_2(sc->as_res,
256 				    ALTERA_SDCARD_OFF_RXTX_BUFFER + i);
257 				d = *(uint16_t *)((uint8_t *)data + i);
258 				if (v != d) {
259 					if (retry_counter == 0) {
260 						bus_write_2(sc->as_res,
261 						    ALTERA_SDCARD_OFF_RXTX_BUFFER + i,
262 						    d);
263 						v = bus_read_2(sc->as_res,
264 						    ALTERA_SDCARD_OFF_RXTX_BUFFER + i);
265 						if (v == d) {
266 							corrections++;
267 							device_printf(sc->as_dev,
268 							    "%s: single word rewrite worked"
269 							    " at offset %u\n",
270 							    __func__, i);
271 							continue;
272 						}
273 					}
274 					differences++;
275 					device_printf(sc->as_dev,
276 					    "%s: retrying write -- difference"
277 					    " %u at offset %u, retry %u\n",
278 					    __func__, differences, i,
279 					    retry_counter);
280 				}
281 			}
282 			if (differences != 0) {
283 				retry_counter++;
284 				if (retry_counter == 1 &&
285 				    corrections == differences)
286 					goto recheck;
287 			}
288 		}
289 	} while (differences != 0);
290 	if (retry_counter)
291 		device_printf(sc->as_dev, "%s: succeeded after %u retries\n",
292 		    __func__, retry_counter);
293 }
294 
295 static void
296 altera_sdcard_io_start_internal(struct altera_sdcard_softc *sc, struct bio *bp)
297 {
298 
299 	switch (bp->bio_cmd) {
300 	case BIO_READ:
301 		altera_sdcard_write_cmd_arg(sc, bp->bio_pblkno *
302 		    ALTERA_SDCARD_SECTORSIZE);
303 		altera_sdcard_write_cmd(sc, ALTERA_SDCARD_CMD_READ_BLOCK);
304 		break;
305 
306 	case BIO_WRITE:
307 		altera_sdcard_write_rxtx_buffer(sc, bp->bio_data,
308 		    bp->bio_bcount);
309 		altera_sdcard_write_cmd_arg(sc, bp->bio_pblkno *
310 		    ALTERA_SDCARD_SECTORSIZE);
311 		altera_sdcard_write_cmd(sc, ALTERA_SDCARD_CMD_WRITE_BLOCK);
312 		break;
313 
314 	default:
315 		panic("%s: unsupported I/O operation %d", __func__,
316 		    bp->bio_cmd);
317 	}
318 }
319 
320 void
321 altera_sdcard_io_start(struct altera_sdcard_softc *sc, struct bio *bp)
322 {
323 
324 	ALTERA_SDCARD_LOCK_ASSERT(sc);
325 	KASSERT(sc->as_currentbio == NULL,
326 	    ("%s: bio already started", __func__));
327 
328 	/*
329 	 * We advertise a block size and maximum I/O size up the stack of the
330 	 * SD Card IP Core sector size.  Catch any attempts to not follow the
331 	 * rules.
332 	 */
333 	KASSERT(bp->bio_bcount == ALTERA_SDCARD_SECTORSIZE,
334 	    ("%s: I/O size not %d", __func__, ALTERA_SDCARD_SECTORSIZE));
335 	altera_sdcard_io_start_internal(sc, bp);
336 	sc->as_currentbio = bp;
337 	sc->as_retriesleft = ALTERA_SDCARD_RETRY_LIMIT;
338 }
339 
340 /*
341  * Handle completed I/O.  ASR is passed in to avoid reading it more than once.
342  * Return 1 if the I/O is actually complete (success, or retry limit
343  * exceeded), or 0 if not.
344  */
345 int
346 altera_sdcard_io_complete(struct altera_sdcard_softc *sc, uint16_t asr)
347 {
348 	struct bio *bp;
349 	uint16_t rr1, mask;
350 	int error;
351 
352 	ALTERA_SDCARD_LOCK_ASSERT(sc);
353 	KASSERT(!(asr & ALTERA_SDCARD_ASR_CMDINPROGRESS),
354 	    ("%s: still in progress", __func__));
355 	KASSERT(asr & ALTERA_SDCARD_ASR_CARDPRESENT,
356 	    ("%s: card removed", __func__));
357 
358 	bp = sc->as_currentbio;
359 
360 	/*-
361 	 * Handle I/O retries if an error is returned by the device.  Various
362 	 * quirks handled in the process:
363 	 *
364 	 * 1. ALTERA_SDCARD_ASR_CMDDATAERROR is ignored for BIO_WRITE.
365 	 * 2. ALTERA_SDCARD_RR1_COMMANDCRCFAILED is optionally ignored for
366 	 *    BIO_READ.
367 	 */
368 	error = 0;
369 	rr1 = altera_sdcard_read_rr1(sc);
370 	switch (bp->bio_cmd) {
371 	case BIO_READ:
372 		mask = ALTERA_SDCARD_RR1_ERRORMASK;
373 		if (altera_sdcard_ignore_crc_errors)
374 			mask &= ~ALTERA_SDCARD_RR1_COMMANDCRCFAILED;
375 		if (asr & ALTERA_SDCARD_ASR_CMDTIMEOUT)
376 			error = EIO;
377 		else if ((asr & ALTERA_SDCARD_ASR_CMDDATAERROR) &&
378 		    (rr1 & mask))
379 			error = EIO;
380 		else
381 			error = 0;
382 		break;
383 
384 	case BIO_WRITE:
385 		if (asr & ALTERA_SDCARD_ASR_CMDTIMEOUT)
386 			error = EIO;
387 		else
388 			error = 0;
389 		break;
390 
391 	default:
392 		break;
393 	}
394 	if (error) {
395 		sc->as_retriesleft--;
396 		if (sc->as_retriesleft == 0 || bootverbose)
397 			device_printf(sc->as_dev, "%s: %s operation block %ju "
398 			    "length %ju failed; asr 0x%08x (rr1: 0x%04x)%s\n",
399 			    __func__, bp->bio_cmd == BIO_READ ? "BIO_READ" :
400 			    (bp->bio_cmd == BIO_WRITE ? "BIO_WRITE" :
401 			    "unknown"),
402 			    bp->bio_pblkno, bp->bio_bcount, asr, rr1,
403 			    sc->as_retriesleft != 0 ? " retrying" : "");
404 		/*
405 		 * This attempt experienced an error; possibly retry.
406 		 */
407 		if (sc->as_retriesleft != 0) {
408 			sc->as_flags |= ALTERA_SDCARD_FLAG_IOERROR;
409 			altera_sdcard_io_start_internal(sc, bp);
410 			return (0);
411 		}
412 		sc->as_flags &= ~ALTERA_SDCARD_FLAG_IOERROR;
413 	} else {
414 		/*
415 		 * Successful I/O completion path.
416 		 */
417 		if (sc->as_flags & ALTERA_SDCARD_FLAG_IOERROR) {
418 			device_printf(sc->as_dev, "%s: %s operation block %ju"
419 			    " length %ju succeeded after %d retries\n",
420 			    __func__, bp->bio_cmd == BIO_READ ? "BIO_READ" :
421 			    (bp->bio_cmd == BIO_WRITE ? "write" : "unknown"),
422 			    bp->bio_pblkno, bp->bio_bcount,
423 			    ALTERA_SDCARD_RETRY_LIMIT - sc->as_retriesleft);
424 			sc->as_flags &= ~ALTERA_SDCARD_FLAG_IOERROR;
425 		}
426 		switch (bp->bio_cmd) {
427 		case BIO_READ:
428 			altera_sdcard_read_rxtx_buffer(sc, bp->bio_data,
429 			    bp->bio_bcount);
430 			break;
431 
432 		case BIO_WRITE:
433 			break;
434 
435 		default:
436 			panic("%s: unsupported I/O operation %d", __func__,
437 			    bp->bio_cmd);
438 		}
439 		bp->bio_resid = 0;
440 		error = 0;
441 	}
442 	biofinish(bp, NULL, error);
443 	sc->as_currentbio = NULL;
444 	return (1);
445 }
446