xref: /openbmc/linux/drivers/mmc/host/bcm2835.c (revision ca481398)
1 /*
2  * bcm2835 sdhost driver.
3  *
4  * The 2835 has two SD controllers: The Arasan sdhci controller
5  * (supported by the iproc driver) and a custom sdhost controller
6  * (supported by this driver).
7  *
8  * The sdhci controller supports both sdcard and sdio.  The sdhost
9  * controller supports the sdcard only, but has better performance.
10  * Also note that the rpi3 has sdio wifi, so driving the sdcard with
11  * the sdhost controller allows to use the sdhci controller for wifi
12  * support.
13  *
14  * The configuration is done by devicetree via pin muxing.  Both
15  * SD controller are available on the same pins (2 pin groups = pin 22
16  * to 27 + pin 48 to 53).  So it's possible to use both SD controllers
17  * at the same time with different pin groups.
18  *
19  * Author:      Phil Elwell <phil@raspberrypi.org>
20  *              Copyright (C) 2015-2016 Raspberry Pi (Trading) Ltd.
21  *
22  * Based on
23  *  mmc-bcm2835.c by Gellert Weisz
24  * which is, in turn, based on
25  *  sdhci-bcm2708.c by Broadcom
26  *  sdhci-bcm2835.c by Stephen Warren and Oleksandr Tymoshenko
27  *  sdhci.c and sdhci-pci.c by Pierre Ossman
28  *
29  * This program is free software; you can redistribute it and/or modify it
30  * under the terms and conditions of the GNU General Public License,
31  * version 2, as published by the Free Software Foundation.
32  *
33  * This program is distributed in the hope it will be useful, but WITHOUT
34  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
35  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
36  * more details.
37  *
38  * You should have received a copy of the GNU General Public License
39  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
40  */
41 #include <linux/clk.h>
42 #include <linux/delay.h>
43 #include <linux/device.h>
44 #include <linux/dmaengine.h>
45 #include <linux/dma-mapping.h>
46 #include <linux/err.h>
47 #include <linux/highmem.h>
48 #include <linux/interrupt.h>
49 #include <linux/io.h>
50 #include <linux/iopoll.h>
51 #include <linux/module.h>
52 #include <linux/of_address.h>
53 #include <linux/of_irq.h>
54 #include <linux/platform_device.h>
55 #include <linux/scatterlist.h>
56 #include <linux/time.h>
57 #include <linux/workqueue.h>
58 
59 #include <linux/mmc/host.h>
60 #include <linux/mmc/mmc.h>
61 #include <linux/mmc/sd.h>
62 
63 #define SDCMD  0x00 /* Command to SD card              - 16 R/W */
64 #define SDARG  0x04 /* Argument to SD card             - 32 R/W */
65 #define SDTOUT 0x08 /* Start value for timeout counter - 32 R/W */
66 #define SDCDIV 0x0c /* Start value for clock divider   - 11 R/W */
67 #define SDRSP0 0x10 /* SD card response (31:0)         - 32 R   */
68 #define SDRSP1 0x14 /* SD card response (63:32)        - 32 R   */
69 #define SDRSP2 0x18 /* SD card response (95:64)        - 32 R   */
70 #define SDRSP3 0x1c /* SD card response (127:96)       - 32 R   */
71 #define SDHSTS 0x20 /* SD host status                  - 11 R/W */
72 #define SDVDD  0x30 /* SD card power control           -  1 R/W */
73 #define SDEDM  0x34 /* Emergency Debug Mode            - 13 R/W */
74 #define SDHCFG 0x38 /* Host configuration              -  2 R/W */
75 #define SDHBCT 0x3c /* Host byte count (debug)         - 32 R/W */
76 #define SDDATA 0x40 /* Data to/from SD card            - 32 R/W */
77 #define SDHBLC 0x50 /* Host block count (SDIO/SDHC)    -  9 R/W */
78 
79 #define SDCMD_NEW_FLAG			0x8000
80 #define SDCMD_FAIL_FLAG			0x4000
81 #define SDCMD_BUSYWAIT			0x800
82 #define SDCMD_NO_RESPONSE		0x400
83 #define SDCMD_LONG_RESPONSE		0x200
84 #define SDCMD_WRITE_CMD			0x80
85 #define SDCMD_READ_CMD			0x40
86 #define SDCMD_CMD_MASK			0x3f
87 
88 #define SDCDIV_MAX_CDIV			0x7ff
89 
90 #define SDHSTS_BUSY_IRPT		0x400
91 #define SDHSTS_BLOCK_IRPT		0x200
92 #define SDHSTS_SDIO_IRPT		0x100
93 #define SDHSTS_REW_TIME_OUT		0x80
94 #define SDHSTS_CMD_TIME_OUT		0x40
95 #define SDHSTS_CRC16_ERROR		0x20
96 #define SDHSTS_CRC7_ERROR		0x10
97 #define SDHSTS_FIFO_ERROR		0x08
98 /* Reserved */
99 /* Reserved */
100 #define SDHSTS_DATA_FLAG		0x01
101 
102 #define SDHSTS_TRANSFER_ERROR_MASK	(SDHSTS_CRC7_ERROR | \
103 					 SDHSTS_CRC16_ERROR | \
104 					 SDHSTS_REW_TIME_OUT | \
105 					 SDHSTS_FIFO_ERROR)
106 
107 #define SDHSTS_ERROR_MASK		(SDHSTS_CMD_TIME_OUT | \
108 					 SDHSTS_TRANSFER_ERROR_MASK)
109 
110 #define SDHCFG_BUSY_IRPT_EN	BIT(10)
111 #define SDHCFG_BLOCK_IRPT_EN	BIT(8)
112 #define SDHCFG_SDIO_IRPT_EN	BIT(5)
113 #define SDHCFG_DATA_IRPT_EN	BIT(4)
114 #define SDHCFG_SLOW_CARD	BIT(3)
115 #define SDHCFG_WIDE_EXT_BUS	BIT(2)
116 #define SDHCFG_WIDE_INT_BUS	BIT(1)
117 #define SDHCFG_REL_CMD_LINE	BIT(0)
118 
119 #define SDVDD_POWER_OFF		0
120 #define SDVDD_POWER_ON		1
121 
122 #define SDEDM_FORCE_DATA_MODE	BIT(19)
123 #define SDEDM_CLOCK_PULSE	BIT(20)
124 #define SDEDM_BYPASS		BIT(21)
125 
126 #define SDEDM_WRITE_THRESHOLD_SHIFT	9
127 #define SDEDM_READ_THRESHOLD_SHIFT	14
128 #define SDEDM_THRESHOLD_MASK		0x1f
129 
130 #define SDEDM_FSM_MASK		0xf
131 #define SDEDM_FSM_IDENTMODE	0x0
132 #define SDEDM_FSM_DATAMODE	0x1
133 #define SDEDM_FSM_READDATA	0x2
134 #define SDEDM_FSM_WRITEDATA	0x3
135 #define SDEDM_FSM_READWAIT	0x4
136 #define SDEDM_FSM_READCRC	0x5
137 #define SDEDM_FSM_WRITECRC	0x6
138 #define SDEDM_FSM_WRITEWAIT1	0x7
139 #define SDEDM_FSM_POWERDOWN	0x8
140 #define SDEDM_FSM_POWERUP	0x9
141 #define SDEDM_FSM_WRITESTART1	0xa
142 #define SDEDM_FSM_WRITESTART2	0xb
143 #define SDEDM_FSM_GENPULSES	0xc
144 #define SDEDM_FSM_WRITEWAIT2	0xd
145 #define SDEDM_FSM_STARTPOWDOWN	0xf
146 
147 #define SDDATA_FIFO_WORDS	16
148 
149 #define FIFO_READ_THRESHOLD	4
150 #define FIFO_WRITE_THRESHOLD	4
151 #define SDDATA_FIFO_PIO_BURST	8
152 
153 #define PIO_THRESHOLD	1  /* Maximum block count for PIO (0 = always DMA) */
154 
155 struct bcm2835_host {
156 	spinlock_t		lock;
157 	struct mutex		mutex;
158 
159 	void __iomem		*ioaddr;
160 	u32			phys_addr;
161 
162 	struct mmc_host		*mmc;
163 	struct platform_device	*pdev;
164 
165 	int			clock;		/* Current clock speed */
166 	unsigned int		max_clk;	/* Max possible freq */
167 	struct work_struct	dma_work;
168 	struct delayed_work	timeout_work;	/* Timer for timeouts */
169 	struct sg_mapping_iter	sg_miter;	/* SG state for PIO */
170 	unsigned int		blocks;		/* remaining PIO blocks */
171 	int			irq;		/* Device IRQ */
172 
173 	u32			ns_per_fifo_word;
174 
175 	/* cached registers */
176 	u32			hcfg;
177 	u32			cdiv;
178 
179 	struct mmc_request	*mrq;		/* Current request */
180 	struct mmc_command	*cmd;		/* Current command */
181 	struct mmc_data		*data;		/* Current data request */
182 	bool			data_complete:1;/* Data finished before cmd */
183 	bool			use_busy:1;	/* Wait for busy interrupt */
184 	bool			use_sbc:1;	/* Send CMD23 */
185 
186 	/* for threaded irq handler */
187 	bool			irq_block;
188 	bool			irq_busy;
189 	bool			irq_data;
190 
191 	/* DMA part */
192 	struct dma_chan		*dma_chan_rxtx;
193 	struct dma_chan		*dma_chan;
194 	struct dma_slave_config dma_cfg_rx;
195 	struct dma_slave_config dma_cfg_tx;
196 	struct dma_async_tx_descriptor	*dma_desc;
197 	u32			dma_dir;
198 	u32			drain_words;
199 	struct page		*drain_page;
200 	u32			drain_offset;
201 	bool			use_dma;
202 };
203 
204 static void bcm2835_dumpcmd(struct bcm2835_host *host, struct mmc_command *cmd,
205 			    const char *label)
206 {
207 	struct device *dev = &host->pdev->dev;
208 
209 	if (!cmd)
210 		return;
211 
212 	dev_dbg(dev, "%c%s op %d arg 0x%x flags 0x%x - resp %08x %08x %08x %08x, err %d\n",
213 		(cmd == host->cmd) ? '>' : ' ',
214 		label, cmd->opcode, cmd->arg, cmd->flags,
215 		cmd->resp[0], cmd->resp[1], cmd->resp[2], cmd->resp[3],
216 		cmd->error);
217 }
218 
219 static void bcm2835_dumpregs(struct bcm2835_host *host)
220 {
221 	struct mmc_request *mrq = host->mrq;
222 	struct device *dev = &host->pdev->dev;
223 
224 	if (mrq) {
225 		bcm2835_dumpcmd(host, mrq->sbc, "sbc");
226 		bcm2835_dumpcmd(host, mrq->cmd, "cmd");
227 		if (mrq->data) {
228 			dev_dbg(dev, "data blocks %x blksz %x - err %d\n",
229 				mrq->data->blocks,
230 				mrq->data->blksz,
231 				mrq->data->error);
232 		}
233 		bcm2835_dumpcmd(host, mrq->stop, "stop");
234 	}
235 
236 	dev_dbg(dev, "=========== REGISTER DUMP ===========\n");
237 	dev_dbg(dev, "SDCMD  0x%08x\n", readl(host->ioaddr + SDCMD));
238 	dev_dbg(dev, "SDARG  0x%08x\n", readl(host->ioaddr + SDARG));
239 	dev_dbg(dev, "SDTOUT 0x%08x\n", readl(host->ioaddr + SDTOUT));
240 	dev_dbg(dev, "SDCDIV 0x%08x\n", readl(host->ioaddr + SDCDIV));
241 	dev_dbg(dev, "SDRSP0 0x%08x\n", readl(host->ioaddr + SDRSP0));
242 	dev_dbg(dev, "SDRSP1 0x%08x\n", readl(host->ioaddr + SDRSP1));
243 	dev_dbg(dev, "SDRSP2 0x%08x\n", readl(host->ioaddr + SDRSP2));
244 	dev_dbg(dev, "SDRSP3 0x%08x\n", readl(host->ioaddr + SDRSP3));
245 	dev_dbg(dev, "SDHSTS 0x%08x\n", readl(host->ioaddr + SDHSTS));
246 	dev_dbg(dev, "SDVDD  0x%08x\n", readl(host->ioaddr + SDVDD));
247 	dev_dbg(dev, "SDEDM  0x%08x\n", readl(host->ioaddr + SDEDM));
248 	dev_dbg(dev, "SDHCFG 0x%08x\n", readl(host->ioaddr + SDHCFG));
249 	dev_dbg(dev, "SDHBCT 0x%08x\n", readl(host->ioaddr + SDHBCT));
250 	dev_dbg(dev, "SDHBLC 0x%08x\n", readl(host->ioaddr + SDHBLC));
251 	dev_dbg(dev, "===========================================\n");
252 }
253 
254 static void bcm2835_reset_internal(struct bcm2835_host *host)
255 {
256 	u32 temp;
257 
258 	writel(SDVDD_POWER_OFF, host->ioaddr + SDVDD);
259 	writel(0, host->ioaddr + SDCMD);
260 	writel(0, host->ioaddr + SDARG);
261 	writel(0xf00000, host->ioaddr + SDTOUT);
262 	writel(0, host->ioaddr + SDCDIV);
263 	writel(0x7f8, host->ioaddr + SDHSTS); /* Write 1s to clear */
264 	writel(0, host->ioaddr + SDHCFG);
265 	writel(0, host->ioaddr + SDHBCT);
266 	writel(0, host->ioaddr + SDHBLC);
267 
268 	/* Limit fifo usage due to silicon bug */
269 	temp = readl(host->ioaddr + SDEDM);
270 	temp &= ~((SDEDM_THRESHOLD_MASK << SDEDM_READ_THRESHOLD_SHIFT) |
271 		  (SDEDM_THRESHOLD_MASK << SDEDM_WRITE_THRESHOLD_SHIFT));
272 	temp |= (FIFO_READ_THRESHOLD << SDEDM_READ_THRESHOLD_SHIFT) |
273 		(FIFO_WRITE_THRESHOLD << SDEDM_WRITE_THRESHOLD_SHIFT);
274 	writel(temp, host->ioaddr + SDEDM);
275 	msleep(20);
276 	writel(SDVDD_POWER_ON, host->ioaddr + SDVDD);
277 	msleep(20);
278 	host->clock = 0;
279 	writel(host->hcfg, host->ioaddr + SDHCFG);
280 	writel(host->cdiv, host->ioaddr + SDCDIV);
281 }
282 
283 static void bcm2835_reset(struct mmc_host *mmc)
284 {
285 	struct bcm2835_host *host = mmc_priv(mmc);
286 
287 	if (host->dma_chan)
288 		dmaengine_terminate_sync(host->dma_chan);
289 	bcm2835_reset_internal(host);
290 }
291 
292 static void bcm2835_finish_command(struct bcm2835_host *host);
293 
294 static void bcm2835_wait_transfer_complete(struct bcm2835_host *host)
295 {
296 	int timediff;
297 	u32 alternate_idle;
298 
299 	alternate_idle = (host->mrq->data->flags & MMC_DATA_READ) ?
300 		SDEDM_FSM_READWAIT : SDEDM_FSM_WRITESTART1;
301 
302 	timediff = 0;
303 
304 	while (1) {
305 		u32 edm, fsm;
306 
307 		edm = readl(host->ioaddr + SDEDM);
308 		fsm = edm & SDEDM_FSM_MASK;
309 
310 		if ((fsm == SDEDM_FSM_IDENTMODE) ||
311 		    (fsm == SDEDM_FSM_DATAMODE))
312 			break;
313 		if (fsm == alternate_idle) {
314 			writel(edm | SDEDM_FORCE_DATA_MODE,
315 			       host->ioaddr + SDEDM);
316 			break;
317 		}
318 
319 		timediff++;
320 		if (timediff == 100000) {
321 			dev_err(&host->pdev->dev,
322 				"wait_transfer_complete - still waiting after %d retries\n",
323 				timediff);
324 			bcm2835_dumpregs(host);
325 			host->mrq->data->error = -ETIMEDOUT;
326 			return;
327 		}
328 		cpu_relax();
329 	}
330 }
331 
332 static void bcm2835_dma_complete(void *param)
333 {
334 	struct bcm2835_host *host = param;
335 
336 	schedule_work(&host->dma_work);
337 }
338 
339 static void bcm2835_transfer_block_pio(struct bcm2835_host *host, bool is_read)
340 {
341 	unsigned long flags;
342 	size_t blksize;
343 	unsigned long wait_max;
344 
345 	blksize = host->data->blksz;
346 
347 	wait_max = jiffies + msecs_to_jiffies(500);
348 
349 	local_irq_save(flags);
350 
351 	while (blksize) {
352 		int copy_words;
353 		u32 hsts = 0;
354 		size_t len;
355 		u32 *buf;
356 
357 		if (!sg_miter_next(&host->sg_miter)) {
358 			host->data->error = -EINVAL;
359 			break;
360 		}
361 
362 		len = min(host->sg_miter.length, blksize);
363 		if (len % 4) {
364 			host->data->error = -EINVAL;
365 			break;
366 		}
367 
368 		blksize -= len;
369 		host->sg_miter.consumed = len;
370 
371 		buf = (u32 *)host->sg_miter.addr;
372 
373 		copy_words = len / 4;
374 
375 		while (copy_words) {
376 			int burst_words, words;
377 			u32 edm;
378 
379 			burst_words = min(SDDATA_FIFO_PIO_BURST, copy_words);
380 			edm = readl(host->ioaddr + SDEDM);
381 			if (is_read)
382 				words = ((edm >> 4) & 0x1f);
383 			else
384 				words = SDDATA_FIFO_WORDS - ((edm >> 4) & 0x1f);
385 
386 			if (words < burst_words) {
387 				int fsm_state = (edm & SDEDM_FSM_MASK);
388 				struct device *dev = &host->pdev->dev;
389 
390 				if ((is_read &&
391 				     (fsm_state != SDEDM_FSM_READDATA &&
392 				      fsm_state != SDEDM_FSM_READWAIT &&
393 				      fsm_state != SDEDM_FSM_READCRC)) ||
394 				    (!is_read &&
395 				     (fsm_state != SDEDM_FSM_WRITEDATA &&
396 				      fsm_state != SDEDM_FSM_WRITESTART1 &&
397 				      fsm_state != SDEDM_FSM_WRITESTART2))) {
398 					hsts = readl(host->ioaddr + SDHSTS);
399 					dev_err(dev, "fsm %x, hsts %08x\n",
400 						fsm_state, hsts);
401 					if (hsts & SDHSTS_ERROR_MASK)
402 						break;
403 				}
404 
405 				if (time_after(jiffies, wait_max)) {
406 					dev_err(dev, "PIO %s timeout - EDM %08x\n",
407 						is_read ? "read" : "write",
408 						edm);
409 					hsts = SDHSTS_REW_TIME_OUT;
410 					break;
411 				}
412 				ndelay((burst_words - words) *
413 				       host->ns_per_fifo_word);
414 				continue;
415 			} else if (words > copy_words) {
416 				words = copy_words;
417 			}
418 
419 			copy_words -= words;
420 
421 			while (words) {
422 				if (is_read)
423 					*(buf++) = readl(host->ioaddr + SDDATA);
424 				else
425 					writel(*(buf++), host->ioaddr + SDDATA);
426 				words--;
427 			}
428 		}
429 
430 		if (hsts & SDHSTS_ERROR_MASK)
431 			break;
432 	}
433 
434 	sg_miter_stop(&host->sg_miter);
435 
436 	local_irq_restore(flags);
437 }
438 
439 static void bcm2835_transfer_pio(struct bcm2835_host *host)
440 {
441 	struct device *dev = &host->pdev->dev;
442 	u32 sdhsts;
443 	bool is_read;
444 
445 	is_read = (host->data->flags & MMC_DATA_READ) != 0;
446 	bcm2835_transfer_block_pio(host, is_read);
447 
448 	sdhsts = readl(host->ioaddr + SDHSTS);
449 	if (sdhsts & (SDHSTS_CRC16_ERROR |
450 		      SDHSTS_CRC7_ERROR |
451 		      SDHSTS_FIFO_ERROR)) {
452 		dev_err(dev, "%s transfer error - HSTS %08x\n",
453 			is_read ? "read" : "write", sdhsts);
454 		host->data->error = -EILSEQ;
455 	} else if ((sdhsts & (SDHSTS_CMD_TIME_OUT |
456 			      SDHSTS_REW_TIME_OUT))) {
457 		dev_err(dev, "%s timeout error - HSTS %08x\n",
458 			is_read ? "read" : "write", sdhsts);
459 		host->data->error = -ETIMEDOUT;
460 	}
461 }
462 
463 static
464 void bcm2835_prepare_dma(struct bcm2835_host *host, struct mmc_data *data)
465 {
466 	int len, dir_data, dir_slave;
467 	struct dma_async_tx_descriptor *desc = NULL;
468 	struct dma_chan *dma_chan;
469 
470 	dma_chan = host->dma_chan_rxtx;
471 	if (data->flags & MMC_DATA_READ) {
472 		dir_data = DMA_FROM_DEVICE;
473 		dir_slave = DMA_DEV_TO_MEM;
474 	} else {
475 		dir_data = DMA_TO_DEVICE;
476 		dir_slave = DMA_MEM_TO_DEV;
477 	}
478 
479 	/* The block doesn't manage the FIFO DREQs properly for
480 	 * multi-block transfers, so don't attempt to DMA the final
481 	 * few words.  Unfortunately this requires the final sg entry
482 	 * to be trimmed.  N.B. This code demands that the overspill
483 	 * is contained in a single sg entry.
484 	 */
485 
486 	host->drain_words = 0;
487 	if ((data->blocks > 1) && (dir_data == DMA_FROM_DEVICE)) {
488 		struct scatterlist *sg;
489 		u32 len;
490 		int i;
491 
492 		len = min((u32)(FIFO_READ_THRESHOLD - 1) * 4,
493 			  (u32)data->blocks * data->blksz);
494 
495 		for_each_sg(data->sg, sg, data->sg_len, i) {
496 			if (sg_is_last(sg)) {
497 				WARN_ON(sg->length < len);
498 				sg->length -= len;
499 				host->drain_page = sg_page(sg);
500 				host->drain_offset = sg->offset + sg->length;
501 			}
502 		}
503 		host->drain_words = len / 4;
504 	}
505 
506 	/* The parameters have already been validated, so this will not fail */
507 	(void)dmaengine_slave_config(dma_chan,
508 				     (dir_data == DMA_FROM_DEVICE) ?
509 				     &host->dma_cfg_rx :
510 				     &host->dma_cfg_tx);
511 
512 	len = dma_map_sg(dma_chan->device->dev, data->sg, data->sg_len,
513 			 dir_data);
514 
515 	if (len > 0) {
516 		desc = dmaengine_prep_slave_sg(dma_chan, data->sg,
517 					       len, dir_slave,
518 					       DMA_PREP_INTERRUPT |
519 					       DMA_CTRL_ACK);
520 	}
521 
522 	if (desc) {
523 		desc->callback = bcm2835_dma_complete;
524 		desc->callback_param = host;
525 		host->dma_desc = desc;
526 		host->dma_chan = dma_chan;
527 		host->dma_dir = dir_data;
528 	}
529 }
530 
531 static void bcm2835_start_dma(struct bcm2835_host *host)
532 {
533 	dmaengine_submit(host->dma_desc);
534 	dma_async_issue_pending(host->dma_chan);
535 }
536 
537 static void bcm2835_set_transfer_irqs(struct bcm2835_host *host)
538 {
539 	u32 all_irqs = SDHCFG_DATA_IRPT_EN | SDHCFG_BLOCK_IRPT_EN |
540 		SDHCFG_BUSY_IRPT_EN;
541 
542 	if (host->dma_desc) {
543 		host->hcfg = (host->hcfg & ~all_irqs) |
544 			SDHCFG_BUSY_IRPT_EN;
545 	} else {
546 		host->hcfg = (host->hcfg & ~all_irqs) |
547 			SDHCFG_DATA_IRPT_EN |
548 			SDHCFG_BUSY_IRPT_EN;
549 	}
550 
551 	writel(host->hcfg, host->ioaddr + SDHCFG);
552 }
553 
554 static
555 void bcm2835_prepare_data(struct bcm2835_host *host, struct mmc_command *cmd)
556 {
557 	struct mmc_data *data = cmd->data;
558 
559 	WARN_ON(host->data);
560 
561 	host->data = data;
562 	if (!data)
563 		return;
564 
565 	host->data_complete = false;
566 	host->data->bytes_xfered = 0;
567 
568 	if (!host->dma_desc) {
569 		/* Use PIO */
570 		int flags = SG_MITER_ATOMIC;
571 
572 		if (data->flags & MMC_DATA_READ)
573 			flags |= SG_MITER_TO_SG;
574 		else
575 			flags |= SG_MITER_FROM_SG;
576 		sg_miter_start(&host->sg_miter, data->sg, data->sg_len, flags);
577 		host->blocks = data->blocks;
578 	}
579 
580 	bcm2835_set_transfer_irqs(host);
581 
582 	writel(data->blksz, host->ioaddr + SDHBCT);
583 	writel(data->blocks, host->ioaddr + SDHBLC);
584 }
585 
586 static u32 bcm2835_read_wait_sdcmd(struct bcm2835_host *host, u32 max_ms)
587 {
588 	struct device *dev = &host->pdev->dev;
589 	u32 value;
590 	int ret;
591 
592 	ret = readl_poll_timeout(host->ioaddr + SDCMD, value,
593 				 !(value & SDCMD_NEW_FLAG), 1, 10);
594 	if (ret == -ETIMEDOUT)
595 		/* if it takes a while make poll interval bigger */
596 		ret = readl_poll_timeout(host->ioaddr + SDCMD, value,
597 					 !(value & SDCMD_NEW_FLAG),
598 					 10, max_ms * 1000);
599 	if (ret == -ETIMEDOUT)
600 		dev_err(dev, "%s: timeout (%d ms)\n", __func__, max_ms);
601 
602 	return value;
603 }
604 
605 static void bcm2835_finish_request(struct bcm2835_host *host)
606 {
607 	struct dma_chan *terminate_chan = NULL;
608 	struct mmc_request *mrq;
609 
610 	cancel_delayed_work(&host->timeout_work);
611 
612 	mrq = host->mrq;
613 
614 	host->mrq = NULL;
615 	host->cmd = NULL;
616 	host->data = NULL;
617 
618 	host->dma_desc = NULL;
619 	terminate_chan = host->dma_chan;
620 	host->dma_chan = NULL;
621 
622 	if (terminate_chan) {
623 		int err = dmaengine_terminate_all(terminate_chan);
624 
625 		if (err)
626 			dev_err(&host->pdev->dev,
627 				"failed to terminate DMA (%d)\n", err);
628 	}
629 
630 	mmc_request_done(host->mmc, mrq);
631 }
632 
633 static
634 bool bcm2835_send_command(struct bcm2835_host *host, struct mmc_command *cmd)
635 {
636 	struct device *dev = &host->pdev->dev;
637 	u32 sdcmd, sdhsts;
638 	unsigned long timeout;
639 
640 	WARN_ON(host->cmd);
641 
642 	sdcmd = bcm2835_read_wait_sdcmd(host, 100);
643 	if (sdcmd & SDCMD_NEW_FLAG) {
644 		dev_err(dev, "previous command never completed.\n");
645 		bcm2835_dumpregs(host);
646 		cmd->error = -EILSEQ;
647 		bcm2835_finish_request(host);
648 		return false;
649 	}
650 
651 	if (!cmd->data && cmd->busy_timeout > 9000)
652 		timeout = DIV_ROUND_UP(cmd->busy_timeout, 1000) * HZ + HZ;
653 	else
654 		timeout = 10 * HZ;
655 	schedule_delayed_work(&host->timeout_work, timeout);
656 
657 	host->cmd = cmd;
658 
659 	/* Clear any error flags */
660 	sdhsts = readl(host->ioaddr + SDHSTS);
661 	if (sdhsts & SDHSTS_ERROR_MASK)
662 		writel(sdhsts, host->ioaddr + SDHSTS);
663 
664 	if ((cmd->flags & MMC_RSP_136) && (cmd->flags & MMC_RSP_BUSY)) {
665 		dev_err(dev, "unsupported response type!\n");
666 		cmd->error = -EINVAL;
667 		bcm2835_finish_request(host);
668 		return false;
669 	}
670 
671 	bcm2835_prepare_data(host, cmd);
672 
673 	writel(cmd->arg, host->ioaddr + SDARG);
674 
675 	sdcmd = cmd->opcode & SDCMD_CMD_MASK;
676 
677 	host->use_busy = false;
678 	if (!(cmd->flags & MMC_RSP_PRESENT)) {
679 		sdcmd |= SDCMD_NO_RESPONSE;
680 	} else {
681 		if (cmd->flags & MMC_RSP_136)
682 			sdcmd |= SDCMD_LONG_RESPONSE;
683 		if (cmd->flags & MMC_RSP_BUSY) {
684 			sdcmd |= SDCMD_BUSYWAIT;
685 			host->use_busy = true;
686 		}
687 	}
688 
689 	if (cmd->data) {
690 		if (cmd->data->flags & MMC_DATA_WRITE)
691 			sdcmd |= SDCMD_WRITE_CMD;
692 		if (cmd->data->flags & MMC_DATA_READ)
693 			sdcmd |= SDCMD_READ_CMD;
694 	}
695 
696 	writel(sdcmd | SDCMD_NEW_FLAG, host->ioaddr + SDCMD);
697 
698 	return true;
699 }
700 
701 static void bcm2835_transfer_complete(struct bcm2835_host *host)
702 {
703 	struct mmc_data *data;
704 
705 	WARN_ON(!host->data_complete);
706 
707 	data = host->data;
708 	host->data = NULL;
709 
710 	/* Need to send CMD12 if -
711 	 * a) open-ended multiblock transfer (no CMD23)
712 	 * b) error in multiblock transfer
713 	 */
714 	if (host->mrq->stop && (data->error || !host->use_sbc)) {
715 		if (bcm2835_send_command(host, host->mrq->stop)) {
716 			/* No busy, so poll for completion */
717 			if (!host->use_busy)
718 				bcm2835_finish_command(host);
719 		}
720 	} else {
721 		bcm2835_wait_transfer_complete(host);
722 		bcm2835_finish_request(host);
723 	}
724 }
725 
726 static void bcm2835_finish_data(struct bcm2835_host *host)
727 {
728 	struct device *dev = &host->pdev->dev;
729 	struct mmc_data *data;
730 
731 	data = host->data;
732 
733 	host->hcfg &= ~(SDHCFG_DATA_IRPT_EN | SDHCFG_BLOCK_IRPT_EN);
734 	writel(host->hcfg, host->ioaddr + SDHCFG);
735 
736 	data->bytes_xfered = data->error ? 0 : (data->blksz * data->blocks);
737 
738 	host->data_complete = true;
739 
740 	if (host->cmd) {
741 		/* Data managed to finish before the
742 		 * command completed. Make sure we do
743 		 * things in the proper order.
744 		 */
745 		dev_dbg(dev, "Finished early - HSTS %08x\n",
746 			readl(host->ioaddr + SDHSTS));
747 	} else {
748 		bcm2835_transfer_complete(host);
749 	}
750 }
751 
752 static void bcm2835_finish_command(struct bcm2835_host *host)
753 {
754 	struct device *dev = &host->pdev->dev;
755 	struct mmc_command *cmd = host->cmd;
756 	u32 sdcmd;
757 
758 	sdcmd = bcm2835_read_wait_sdcmd(host, 100);
759 
760 	/* Check for errors */
761 	if (sdcmd & SDCMD_NEW_FLAG) {
762 		dev_err(dev, "command never completed.\n");
763 		bcm2835_dumpregs(host);
764 		host->cmd->error = -EIO;
765 		bcm2835_finish_request(host);
766 		return;
767 	} else if (sdcmd & SDCMD_FAIL_FLAG) {
768 		u32 sdhsts = readl(host->ioaddr + SDHSTS);
769 
770 		/* Clear the errors */
771 		writel(SDHSTS_ERROR_MASK, host->ioaddr + SDHSTS);
772 
773 		if (!(sdhsts & SDHSTS_CRC7_ERROR) ||
774 		    (host->cmd->opcode != MMC_SEND_OP_COND)) {
775 			if (sdhsts & SDHSTS_CMD_TIME_OUT) {
776 				host->cmd->error = -ETIMEDOUT;
777 			} else {
778 				dev_err(dev, "unexpected command %d error\n",
779 					host->cmd->opcode);
780 				bcm2835_dumpregs(host);
781 				host->cmd->error = -EILSEQ;
782 			}
783 			bcm2835_finish_request(host);
784 			return;
785 		}
786 	}
787 
788 	if (cmd->flags & MMC_RSP_PRESENT) {
789 		if (cmd->flags & MMC_RSP_136) {
790 			int i;
791 
792 			for (i = 0; i < 4; i++) {
793 				cmd->resp[3 - i] =
794 					readl(host->ioaddr + SDRSP0 + i * 4);
795 			}
796 		} else {
797 			cmd->resp[0] = readl(host->ioaddr + SDRSP0);
798 		}
799 	}
800 
801 	if (cmd == host->mrq->sbc) {
802 		/* Finished CMD23, now send actual command. */
803 		host->cmd = NULL;
804 		if (bcm2835_send_command(host, host->mrq->cmd)) {
805 			if (host->data && host->dma_desc)
806 				/* DMA transfer starts now, PIO starts
807 				 * after irq
808 				 */
809 				bcm2835_start_dma(host);
810 
811 			if (!host->use_busy)
812 				bcm2835_finish_command(host);
813 		}
814 	} else if (cmd == host->mrq->stop) {
815 		/* Finished CMD12 */
816 		bcm2835_finish_request(host);
817 	} else {
818 		/* Processed actual command. */
819 		host->cmd = NULL;
820 		if (!host->data)
821 			bcm2835_finish_request(host);
822 		else if (host->data_complete)
823 			bcm2835_transfer_complete(host);
824 	}
825 }
826 
827 static void bcm2835_timeout(struct work_struct *work)
828 {
829 	struct delayed_work *d = to_delayed_work(work);
830 	struct bcm2835_host *host =
831 		container_of(d, struct bcm2835_host, timeout_work);
832 	struct device *dev = &host->pdev->dev;
833 
834 	mutex_lock(&host->mutex);
835 
836 	if (host->mrq) {
837 		dev_err(dev, "timeout waiting for hardware interrupt.\n");
838 		bcm2835_dumpregs(host);
839 
840 		if (host->data) {
841 			host->data->error = -ETIMEDOUT;
842 			bcm2835_finish_data(host);
843 		} else {
844 			if (host->cmd)
845 				host->cmd->error = -ETIMEDOUT;
846 			else
847 				host->mrq->cmd->error = -ETIMEDOUT;
848 
849 			bcm2835_finish_request(host);
850 		}
851 	}
852 
853 	mutex_unlock(&host->mutex);
854 }
855 
856 static bool bcm2835_check_cmd_error(struct bcm2835_host *host, u32 intmask)
857 {
858 	struct device *dev = &host->pdev->dev;
859 
860 	if (!(intmask & SDHSTS_ERROR_MASK))
861 		return false;
862 
863 	if (!host->cmd)
864 		return true;
865 
866 	dev_err(dev, "sdhost_busy_irq: intmask %08x\n", intmask);
867 	if (intmask & SDHSTS_CRC7_ERROR) {
868 		host->cmd->error = -EILSEQ;
869 	} else if (intmask & (SDHSTS_CRC16_ERROR |
870 			      SDHSTS_FIFO_ERROR)) {
871 		if (host->mrq->data)
872 			host->mrq->data->error = -EILSEQ;
873 		else
874 			host->cmd->error = -EILSEQ;
875 	} else if (intmask & SDHSTS_REW_TIME_OUT) {
876 		if (host->mrq->data)
877 			host->mrq->data->error = -ETIMEDOUT;
878 		else
879 			host->cmd->error = -ETIMEDOUT;
880 	} else if (intmask & SDHSTS_CMD_TIME_OUT) {
881 		host->cmd->error = -ETIMEDOUT;
882 	}
883 	bcm2835_dumpregs(host);
884 	return true;
885 }
886 
887 static void bcm2835_check_data_error(struct bcm2835_host *host, u32 intmask)
888 {
889 	if (!host->data)
890 		return;
891 	if (intmask & (SDHSTS_CRC16_ERROR | SDHSTS_FIFO_ERROR))
892 		host->data->error = -EILSEQ;
893 	if (intmask & SDHSTS_REW_TIME_OUT)
894 		host->data->error = -ETIMEDOUT;
895 }
896 
897 static void bcm2835_busy_irq(struct bcm2835_host *host)
898 {
899 	if (WARN_ON(!host->cmd)) {
900 		bcm2835_dumpregs(host);
901 		return;
902 	}
903 
904 	if (WARN_ON(!host->use_busy)) {
905 		bcm2835_dumpregs(host);
906 		return;
907 	}
908 	host->use_busy = false;
909 
910 	bcm2835_finish_command(host);
911 }
912 
913 static void bcm2835_data_irq(struct bcm2835_host *host, u32 intmask)
914 {
915 	/* There are no dedicated data/space available interrupt
916 	 * status bits, so it is necessary to use the single shared
917 	 * data/space available FIFO status bits. It is therefore not
918 	 * an error to get here when there is no data transfer in
919 	 * progress.
920 	 */
921 	if (!host->data)
922 		return;
923 
924 	bcm2835_check_data_error(host, intmask);
925 	if (host->data->error)
926 		goto finished;
927 
928 	if (host->data->flags & MMC_DATA_WRITE) {
929 		/* Use the block interrupt for writes after the first block */
930 		host->hcfg &= ~(SDHCFG_DATA_IRPT_EN);
931 		host->hcfg |= SDHCFG_BLOCK_IRPT_EN;
932 		writel(host->hcfg, host->ioaddr + SDHCFG);
933 		bcm2835_transfer_pio(host);
934 	} else {
935 		bcm2835_transfer_pio(host);
936 		host->blocks--;
937 		if ((host->blocks == 0) || host->data->error)
938 			goto finished;
939 	}
940 	return;
941 
942 finished:
943 	host->hcfg &= ~(SDHCFG_DATA_IRPT_EN | SDHCFG_BLOCK_IRPT_EN);
944 	writel(host->hcfg, host->ioaddr + SDHCFG);
945 }
946 
947 static void bcm2835_data_threaded_irq(struct bcm2835_host *host)
948 {
949 	if (!host->data)
950 		return;
951 	if ((host->blocks == 0) || host->data->error)
952 		bcm2835_finish_data(host);
953 }
954 
955 static void bcm2835_block_irq(struct bcm2835_host *host)
956 {
957 	if (WARN_ON(!host->data)) {
958 		bcm2835_dumpregs(host);
959 		return;
960 	}
961 
962 	if (!host->dma_desc) {
963 		WARN_ON(!host->blocks);
964 		if (host->data->error || (--host->blocks == 0))
965 			bcm2835_finish_data(host);
966 		else
967 			bcm2835_transfer_pio(host);
968 	} else if (host->data->flags & MMC_DATA_WRITE) {
969 		bcm2835_finish_data(host);
970 	}
971 }
972 
973 static irqreturn_t bcm2835_irq(int irq, void *dev_id)
974 {
975 	irqreturn_t result = IRQ_NONE;
976 	struct bcm2835_host *host = dev_id;
977 	u32 intmask;
978 
979 	spin_lock(&host->lock);
980 
981 	intmask = readl(host->ioaddr + SDHSTS);
982 
983 	writel(SDHSTS_BUSY_IRPT |
984 	       SDHSTS_BLOCK_IRPT |
985 	       SDHSTS_SDIO_IRPT |
986 	       SDHSTS_DATA_FLAG,
987 	       host->ioaddr + SDHSTS);
988 
989 	if (intmask & SDHSTS_BLOCK_IRPT) {
990 		bcm2835_check_data_error(host, intmask);
991 		host->irq_block = true;
992 		result = IRQ_WAKE_THREAD;
993 	}
994 
995 	if (intmask & SDHSTS_BUSY_IRPT) {
996 		if (!bcm2835_check_cmd_error(host, intmask)) {
997 			host->irq_busy = true;
998 			result = IRQ_WAKE_THREAD;
999 		} else {
1000 			result = IRQ_HANDLED;
1001 		}
1002 	}
1003 
1004 	/* There is no true data interrupt status bit, so it is
1005 	 * necessary to qualify the data flag with the interrupt
1006 	 * enable bit.
1007 	 */
1008 	if ((intmask & SDHSTS_DATA_FLAG) &&
1009 	    (host->hcfg & SDHCFG_DATA_IRPT_EN)) {
1010 		bcm2835_data_irq(host, intmask);
1011 		host->irq_data = true;
1012 		result = IRQ_WAKE_THREAD;
1013 	}
1014 
1015 	spin_unlock(&host->lock);
1016 
1017 	return result;
1018 }
1019 
1020 static irqreturn_t bcm2835_threaded_irq(int irq, void *dev_id)
1021 {
1022 	struct bcm2835_host *host = dev_id;
1023 	unsigned long flags;
1024 	bool block, busy, data;
1025 
1026 	spin_lock_irqsave(&host->lock, flags);
1027 
1028 	block = host->irq_block;
1029 	busy  = host->irq_busy;
1030 	data  = host->irq_data;
1031 	host->irq_block = false;
1032 	host->irq_busy  = false;
1033 	host->irq_data  = false;
1034 
1035 	spin_unlock_irqrestore(&host->lock, flags);
1036 
1037 	mutex_lock(&host->mutex);
1038 
1039 	if (block)
1040 		bcm2835_block_irq(host);
1041 	if (busy)
1042 		bcm2835_busy_irq(host);
1043 	if (data)
1044 		bcm2835_data_threaded_irq(host);
1045 
1046 	mutex_unlock(&host->mutex);
1047 
1048 	return IRQ_HANDLED;
1049 }
1050 
1051 static void bcm2835_dma_complete_work(struct work_struct *work)
1052 {
1053 	struct bcm2835_host *host =
1054 		container_of(work, struct bcm2835_host, dma_work);
1055 	struct mmc_data *data = host->data;
1056 
1057 	mutex_lock(&host->mutex);
1058 
1059 	if (host->dma_chan) {
1060 		dma_unmap_sg(host->dma_chan->device->dev,
1061 			     data->sg, data->sg_len,
1062 			     host->dma_dir);
1063 
1064 		host->dma_chan = NULL;
1065 	}
1066 
1067 	if (host->drain_words) {
1068 		unsigned long flags;
1069 		void *page;
1070 		u32 *buf;
1071 
1072 		if (host->drain_offset & PAGE_MASK) {
1073 			host->drain_page += host->drain_offset >> PAGE_SHIFT;
1074 			host->drain_offset &= ~PAGE_MASK;
1075 		}
1076 		local_irq_save(flags);
1077 		page = kmap_atomic(host->drain_page);
1078 		buf = page + host->drain_offset;
1079 
1080 		while (host->drain_words) {
1081 			u32 edm = readl(host->ioaddr + SDEDM);
1082 
1083 			if ((edm >> 4) & 0x1f)
1084 				*(buf++) = readl(host->ioaddr + SDDATA);
1085 			host->drain_words--;
1086 		}
1087 
1088 		kunmap_atomic(page);
1089 		local_irq_restore(flags);
1090 	}
1091 
1092 	bcm2835_finish_data(host);
1093 
1094 	mutex_unlock(&host->mutex);
1095 }
1096 
1097 static void bcm2835_set_clock(struct bcm2835_host *host, unsigned int clock)
1098 {
1099 	int div;
1100 
1101 	/* The SDCDIV register has 11 bits, and holds (div - 2).  But
1102 	 * in data mode the max is 50MHz wihout a minimum, and only
1103 	 * the bottom 3 bits are used. Since the switch over is
1104 	 * automatic (unless we have marked the card as slow...),
1105 	 * chosen values have to make sense in both modes.  Ident mode
1106 	 * must be 100-400KHz, so can range check the requested
1107 	 * clock. CMD15 must be used to return to data mode, so this
1108 	 * can be monitored.
1109 	 *
1110 	 * clock 250MHz -> 0->125MHz, 1->83.3MHz, 2->62.5MHz, 3->50.0MHz
1111 	 *                 4->41.7MHz, 5->35.7MHz, 6->31.3MHz, 7->27.8MHz
1112 	 *
1113 	 *		 623->400KHz/27.8MHz
1114 	 *		 reset value (507)->491159/50MHz
1115 	 *
1116 	 * BUT, the 3-bit clock divisor in data mode is too small if
1117 	 * the core clock is higher than 250MHz, so instead use the
1118 	 * SLOW_CARD configuration bit to force the use of the ident
1119 	 * clock divisor at all times.
1120 	 */
1121 
1122 	if (clock < 100000) {
1123 		/* Can't stop the clock, but make it as slow as possible
1124 		 * to show willing
1125 		 */
1126 		host->cdiv = SDCDIV_MAX_CDIV;
1127 		writel(host->cdiv, host->ioaddr + SDCDIV);
1128 		return;
1129 	}
1130 
1131 	div = host->max_clk / clock;
1132 	if (div < 2)
1133 		div = 2;
1134 	if ((host->max_clk / div) > clock)
1135 		div++;
1136 	div -= 2;
1137 
1138 	if (div > SDCDIV_MAX_CDIV)
1139 		div = SDCDIV_MAX_CDIV;
1140 
1141 	clock = host->max_clk / (div + 2);
1142 	host->mmc->actual_clock = clock;
1143 
1144 	/* Calibrate some delays */
1145 
1146 	host->ns_per_fifo_word = (1000000000 / clock) *
1147 		((host->mmc->caps & MMC_CAP_4_BIT_DATA) ? 8 : 32);
1148 
1149 	host->cdiv = div;
1150 	writel(host->cdiv, host->ioaddr + SDCDIV);
1151 
1152 	/* Set the timeout to 500ms */
1153 	writel(host->mmc->actual_clock / 2, host->ioaddr + SDTOUT);
1154 }
1155 
1156 static void bcm2835_request(struct mmc_host *mmc, struct mmc_request *mrq)
1157 {
1158 	struct bcm2835_host *host = mmc_priv(mmc);
1159 	struct device *dev = &host->pdev->dev;
1160 	u32 edm, fsm;
1161 
1162 	/* Reset the error statuses in case this is a retry */
1163 	if (mrq->sbc)
1164 		mrq->sbc->error = 0;
1165 	if (mrq->cmd)
1166 		mrq->cmd->error = 0;
1167 	if (mrq->data)
1168 		mrq->data->error = 0;
1169 	if (mrq->stop)
1170 		mrq->stop->error = 0;
1171 
1172 	if (mrq->data && !is_power_of_2(mrq->data->blksz)) {
1173 		dev_err(dev, "unsupported block size (%d bytes)\n",
1174 			mrq->data->blksz);
1175 
1176 		if (mrq->cmd)
1177 			mrq->cmd->error = -EINVAL;
1178 
1179 		mmc_request_done(mmc, mrq);
1180 		return;
1181 	}
1182 
1183 	if (host->use_dma && mrq->data && (mrq->data->blocks > PIO_THRESHOLD))
1184 		bcm2835_prepare_dma(host, mrq->data);
1185 
1186 	mutex_lock(&host->mutex);
1187 
1188 	WARN_ON(host->mrq);
1189 	host->mrq = mrq;
1190 
1191 	edm = readl(host->ioaddr + SDEDM);
1192 	fsm = edm & SDEDM_FSM_MASK;
1193 
1194 	if ((fsm != SDEDM_FSM_IDENTMODE) &&
1195 	    (fsm != SDEDM_FSM_DATAMODE)) {
1196 		dev_err(dev, "previous command (%d) not complete (EDM %08x)\n",
1197 			readl(host->ioaddr + SDCMD) & SDCMD_CMD_MASK,
1198 			edm);
1199 		bcm2835_dumpregs(host);
1200 
1201 		if (mrq->cmd)
1202 			mrq->cmd->error = -EILSEQ;
1203 
1204 		bcm2835_finish_request(host);
1205 		mutex_unlock(&host->mutex);
1206 		return;
1207 	}
1208 
1209 	host->use_sbc = !!mrq->sbc && host->mrq->data &&
1210 			(host->mrq->data->flags & MMC_DATA_READ);
1211 	if (host->use_sbc) {
1212 		if (bcm2835_send_command(host, mrq->sbc)) {
1213 			if (!host->use_busy)
1214 				bcm2835_finish_command(host);
1215 		}
1216 	} else if (mrq->cmd && bcm2835_send_command(host, mrq->cmd)) {
1217 		if (host->data && host->dma_desc) {
1218 			/* DMA transfer starts now, PIO starts after irq */
1219 			bcm2835_start_dma(host);
1220 		}
1221 
1222 		if (!host->use_busy)
1223 			bcm2835_finish_command(host);
1224 	}
1225 
1226 	mutex_unlock(&host->mutex);
1227 }
1228 
1229 static void bcm2835_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
1230 {
1231 	struct bcm2835_host *host = mmc_priv(mmc);
1232 
1233 	mutex_lock(&host->mutex);
1234 
1235 	if (!ios->clock || ios->clock != host->clock) {
1236 		bcm2835_set_clock(host, ios->clock);
1237 		host->clock = ios->clock;
1238 	}
1239 
1240 	/* set bus width */
1241 	host->hcfg &= ~SDHCFG_WIDE_EXT_BUS;
1242 	if (ios->bus_width == MMC_BUS_WIDTH_4)
1243 		host->hcfg |= SDHCFG_WIDE_EXT_BUS;
1244 
1245 	host->hcfg |= SDHCFG_WIDE_INT_BUS;
1246 
1247 	/* Disable clever clock switching, to cope with fast core clocks */
1248 	host->hcfg |= SDHCFG_SLOW_CARD;
1249 
1250 	writel(host->hcfg, host->ioaddr + SDHCFG);
1251 
1252 	mutex_unlock(&host->mutex);
1253 }
1254 
1255 static const struct mmc_host_ops bcm2835_ops = {
1256 	.request = bcm2835_request,
1257 	.set_ios = bcm2835_set_ios,
1258 	.hw_reset = bcm2835_reset,
1259 };
1260 
1261 static int bcm2835_add_host(struct bcm2835_host *host)
1262 {
1263 	struct mmc_host *mmc = host->mmc;
1264 	struct device *dev = &host->pdev->dev;
1265 	char pio_limit_string[20];
1266 	int ret;
1267 
1268 	mmc->f_max = host->max_clk;
1269 	mmc->f_min = host->max_clk / SDCDIV_MAX_CDIV;
1270 
1271 	mmc->max_busy_timeout = ~0 / (mmc->f_max / 1000);
1272 
1273 	dev_dbg(dev, "f_max %d, f_min %d, max_busy_timeout %d\n",
1274 		mmc->f_max, mmc->f_min, mmc->max_busy_timeout);
1275 
1276 	/* host controller capabilities */
1277 	mmc->caps |= MMC_CAP_SD_HIGHSPEED | MMC_CAP_MMC_HIGHSPEED |
1278 		     MMC_CAP_NEEDS_POLL | MMC_CAP_HW_RESET | MMC_CAP_ERASE |
1279 		     MMC_CAP_CMD23;
1280 
1281 	spin_lock_init(&host->lock);
1282 	mutex_init(&host->mutex);
1283 
1284 	if (IS_ERR_OR_NULL(host->dma_chan_rxtx)) {
1285 		dev_warn(dev, "unable to initialise DMA channel. Falling back to PIO\n");
1286 		host->use_dma = false;
1287 	} else {
1288 		host->use_dma = true;
1289 
1290 		host->dma_cfg_tx.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1291 		host->dma_cfg_tx.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1292 		host->dma_cfg_tx.slave_id = 13;		/* DREQ channel */
1293 		host->dma_cfg_tx.direction = DMA_MEM_TO_DEV;
1294 		host->dma_cfg_tx.src_addr = 0;
1295 		host->dma_cfg_tx.dst_addr = host->phys_addr + SDDATA;
1296 
1297 		host->dma_cfg_rx.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1298 		host->dma_cfg_rx.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1299 		host->dma_cfg_rx.slave_id = 13;		/* DREQ channel */
1300 		host->dma_cfg_rx.direction = DMA_DEV_TO_MEM;
1301 		host->dma_cfg_rx.src_addr = host->phys_addr + SDDATA;
1302 		host->dma_cfg_rx.dst_addr = 0;
1303 
1304 		if (dmaengine_slave_config(host->dma_chan_rxtx,
1305 					   &host->dma_cfg_tx) != 0 ||
1306 		    dmaengine_slave_config(host->dma_chan_rxtx,
1307 					   &host->dma_cfg_rx) != 0)
1308 			host->use_dma = false;
1309 	}
1310 
1311 	mmc->max_segs = 128;
1312 	mmc->max_req_size = 524288;
1313 	mmc->max_seg_size = mmc->max_req_size;
1314 	mmc->max_blk_size = 1024;
1315 	mmc->max_blk_count =  65535;
1316 
1317 	/* report supported voltage ranges */
1318 	mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
1319 
1320 	INIT_WORK(&host->dma_work, bcm2835_dma_complete_work);
1321 	INIT_DELAYED_WORK(&host->timeout_work, bcm2835_timeout);
1322 
1323 	/* Set interrupt enables */
1324 	host->hcfg = SDHCFG_BUSY_IRPT_EN;
1325 
1326 	bcm2835_reset_internal(host);
1327 
1328 	ret = request_threaded_irq(host->irq, bcm2835_irq,
1329 				   bcm2835_threaded_irq,
1330 				   0, mmc_hostname(mmc), host);
1331 	if (ret) {
1332 		dev_err(dev, "failed to request IRQ %d: %d\n", host->irq, ret);
1333 		return ret;
1334 	}
1335 
1336 	ret = mmc_add_host(mmc);
1337 	if (ret) {
1338 		free_irq(host->irq, host);
1339 		return ret;
1340 	}
1341 
1342 	pio_limit_string[0] = '\0';
1343 	if (host->use_dma && (PIO_THRESHOLD > 0))
1344 		sprintf(pio_limit_string, " (>%d)", PIO_THRESHOLD);
1345 	dev_info(dev, "loaded - DMA %s%s\n",
1346 		 host->use_dma ? "enabled" : "disabled", pio_limit_string);
1347 
1348 	return 0;
1349 }
1350 
1351 static int bcm2835_probe(struct platform_device *pdev)
1352 {
1353 	struct device *dev = &pdev->dev;
1354 	struct clk *clk;
1355 	struct resource *iomem;
1356 	struct bcm2835_host *host;
1357 	struct mmc_host *mmc;
1358 	const __be32 *regaddr_p;
1359 	int ret;
1360 
1361 	dev_dbg(dev, "%s\n", __func__);
1362 	mmc = mmc_alloc_host(sizeof(*host), dev);
1363 	if (!mmc)
1364 		return -ENOMEM;
1365 
1366 	mmc->ops = &bcm2835_ops;
1367 	host = mmc_priv(mmc);
1368 	host->mmc = mmc;
1369 	host->pdev = pdev;
1370 	spin_lock_init(&host->lock);
1371 
1372 	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1373 	host->ioaddr = devm_ioremap_resource(dev, iomem);
1374 	if (IS_ERR(host->ioaddr)) {
1375 		ret = PTR_ERR(host->ioaddr);
1376 		goto err;
1377 	}
1378 
1379 	/* Parse OF address directly to get the physical address for
1380 	 * DMA to our registers.
1381 	 */
1382 	regaddr_p = of_get_address(pdev->dev.of_node, 0, NULL, NULL);
1383 	if (!regaddr_p) {
1384 		dev_err(dev, "Can't get phys address\n");
1385 		ret = -EINVAL;
1386 		goto err;
1387 	}
1388 
1389 	host->phys_addr = be32_to_cpup(regaddr_p);
1390 
1391 	host->dma_chan = NULL;
1392 	host->dma_desc = NULL;
1393 
1394 	host->dma_chan_rxtx = dma_request_slave_channel(dev, "rx-tx");
1395 
1396 	clk = devm_clk_get(dev, NULL);
1397 	if (IS_ERR(clk)) {
1398 		ret = PTR_ERR(clk);
1399 		if (ret != -EPROBE_DEFER)
1400 			dev_err(dev, "could not get clk: %d\n", ret);
1401 		goto err;
1402 	}
1403 
1404 	host->max_clk = clk_get_rate(clk);
1405 
1406 	host->irq = platform_get_irq(pdev, 0);
1407 	if (host->irq <= 0) {
1408 		dev_err(dev, "get IRQ failed\n");
1409 		ret = -EINVAL;
1410 		goto err;
1411 	}
1412 
1413 	ret = mmc_of_parse(mmc);
1414 	if (ret)
1415 		goto err;
1416 
1417 	ret = bcm2835_add_host(host);
1418 	if (ret)
1419 		goto err;
1420 
1421 	platform_set_drvdata(pdev, host);
1422 
1423 	dev_dbg(dev, "%s -> OK\n", __func__);
1424 
1425 	return 0;
1426 
1427 err:
1428 	dev_dbg(dev, "%s -> err %d\n", __func__, ret);
1429 	mmc_free_host(mmc);
1430 
1431 	return ret;
1432 }
1433 
1434 static int bcm2835_remove(struct platform_device *pdev)
1435 {
1436 	struct bcm2835_host *host = platform_get_drvdata(pdev);
1437 
1438 	mmc_remove_host(host->mmc);
1439 
1440 	writel(SDVDD_POWER_OFF, host->ioaddr + SDVDD);
1441 
1442 	free_irq(host->irq, host);
1443 
1444 	cancel_work_sync(&host->dma_work);
1445 	cancel_delayed_work_sync(&host->timeout_work);
1446 
1447 	mmc_free_host(host->mmc);
1448 	platform_set_drvdata(pdev, NULL);
1449 
1450 	return 0;
1451 }
1452 
1453 static const struct of_device_id bcm2835_match[] = {
1454 	{ .compatible = "brcm,bcm2835-sdhost" },
1455 	{ }
1456 };
1457 MODULE_DEVICE_TABLE(of, bcm2835_match);
1458 
1459 static struct platform_driver bcm2835_driver = {
1460 	.probe      = bcm2835_probe,
1461 	.remove     = bcm2835_remove,
1462 	.driver     = {
1463 		.name		= "sdhost-bcm2835",
1464 		.of_match_table	= bcm2835_match,
1465 	},
1466 };
1467 module_platform_driver(bcm2835_driver);
1468 
1469 MODULE_ALIAS("platform:sdhost-bcm2835");
1470 MODULE_DESCRIPTION("BCM2835 SDHost driver");
1471 MODULE_LICENSE("GPL v2");
1472 MODULE_AUTHOR("Phil Elwell");
1473