xref: /linux/drivers/mmc/host/bcm2835.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * bcm2835 sdhost driver.
4  *
5  * The 2835 has two SD controllers: The Arasan sdhci controller
6  * (supported by the iproc driver) and a custom sdhost controller
7  * (supported by this driver).
8  *
9  * The sdhci controller supports both sdcard and sdio.  The sdhost
10  * controller supports the sdcard only, but has better performance.
11  * Also note that the rpi3 has sdio wifi, so driving the sdcard with
12  * the sdhost controller allows to use the sdhci controller for wifi
13  * support.
14  *
15  * The configuration is done by devicetree via pin muxing.  Both
16  * SD controller are available on the same pins (2 pin groups = pin 22
17  * to 27 + pin 48 to 53).  So it's possible to use both SD controllers
18  * at the same time with different pin groups.
19  *
20  * Author:      Phil Elwell <phil@raspberrypi.org>
21  *              Copyright (C) 2015-2016 Raspberry Pi (Trading) Ltd.
22  *
23  * Based on
24  *  mmc-bcm2835.c by Gellert Weisz
25  * which is, in turn, based on
26  *  sdhci-bcm2708.c by Broadcom
27  *  sdhci-bcm2835.c by Stephen Warren and Oleksandr Tymoshenko
28  *  sdhci.c and sdhci-pci.c by Pierre Ossman
29  */
30 #include <linux/clk.h>
31 #include <linux/delay.h>
32 #include <linux/device.h>
33 #include <linux/dmaengine.h>
34 #include <linux/dma-mapping.h>
35 #include <linux/err.h>
36 #include <linux/highmem.h>
37 #include <linux/interrupt.h>
38 #include <linux/io.h>
39 #include <linux/iopoll.h>
40 #include <linux/module.h>
41 #include <linux/of_address.h>
42 #include <linux/of_irq.h>
43 #include <linux/platform_device.h>
44 #include <linux/scatterlist.h>
45 #include <linux/time.h>
46 #include <linux/workqueue.h>
47 
48 #include <linux/mmc/host.h>
49 #include <linux/mmc/mmc.h>
50 #include <linux/mmc/sd.h>
51 
52 #define SDCMD  0x00 /* Command to SD card              - 16 R/W */
53 #define SDARG  0x04 /* Argument to SD card             - 32 R/W */
54 #define SDTOUT 0x08 /* Start value for timeout counter - 32 R/W */
55 #define SDCDIV 0x0c /* Start value for clock divider   - 11 R/W */
56 #define SDRSP0 0x10 /* SD card response (31:0)         - 32 R   */
57 #define SDRSP1 0x14 /* SD card response (63:32)        - 32 R   */
58 #define SDRSP2 0x18 /* SD card response (95:64)        - 32 R   */
59 #define SDRSP3 0x1c /* SD card response (127:96)       - 32 R   */
60 #define SDHSTS 0x20 /* SD host status                  - 11 R/W */
61 #define SDVDD  0x30 /* SD card power control           -  1 R/W */
62 #define SDEDM  0x34 /* Emergency Debug Mode            - 13 R/W */
63 #define SDHCFG 0x38 /* Host configuration              -  2 R/W */
64 #define SDHBCT 0x3c /* Host byte count (debug)         - 32 R/W */
65 #define SDDATA 0x40 /* Data to/from SD card            - 32 R/W */
66 #define SDHBLC 0x50 /* Host block count (SDIO/SDHC)    -  9 R/W */
67 
68 #define SDCMD_NEW_FLAG			0x8000
69 #define SDCMD_FAIL_FLAG			0x4000
70 #define SDCMD_BUSYWAIT			0x800
71 #define SDCMD_NO_RESPONSE		0x400
72 #define SDCMD_LONG_RESPONSE		0x200
73 #define SDCMD_WRITE_CMD			0x80
74 #define SDCMD_READ_CMD			0x40
75 #define SDCMD_CMD_MASK			0x3f
76 
77 #define SDCDIV_MAX_CDIV			0x7ff
78 
79 #define SDHSTS_BUSY_IRPT		0x400
80 #define SDHSTS_BLOCK_IRPT		0x200
81 #define SDHSTS_SDIO_IRPT		0x100
82 #define SDHSTS_REW_TIME_OUT		0x80
83 #define SDHSTS_CMD_TIME_OUT		0x40
84 #define SDHSTS_CRC16_ERROR		0x20
85 #define SDHSTS_CRC7_ERROR		0x10
86 #define SDHSTS_FIFO_ERROR		0x08
87 /* Reserved */
88 /* Reserved */
89 #define SDHSTS_DATA_FLAG		0x01
90 
91 #define SDHSTS_TRANSFER_ERROR_MASK	(SDHSTS_CRC7_ERROR | \
92 					 SDHSTS_CRC16_ERROR | \
93 					 SDHSTS_REW_TIME_OUT | \
94 					 SDHSTS_FIFO_ERROR)
95 
96 #define SDHSTS_ERROR_MASK		(SDHSTS_CMD_TIME_OUT | \
97 					 SDHSTS_TRANSFER_ERROR_MASK)
98 
99 #define SDHCFG_BUSY_IRPT_EN	BIT(10)
100 #define SDHCFG_BLOCK_IRPT_EN	BIT(8)
101 #define SDHCFG_SDIO_IRPT_EN	BIT(5)
102 #define SDHCFG_DATA_IRPT_EN	BIT(4)
103 #define SDHCFG_SLOW_CARD	BIT(3)
104 #define SDHCFG_WIDE_EXT_BUS	BIT(2)
105 #define SDHCFG_WIDE_INT_BUS	BIT(1)
106 #define SDHCFG_REL_CMD_LINE	BIT(0)
107 
108 #define SDVDD_POWER_OFF		0
109 #define SDVDD_POWER_ON		1
110 
111 #define SDEDM_FORCE_DATA_MODE	BIT(19)
112 #define SDEDM_CLOCK_PULSE	BIT(20)
113 #define SDEDM_BYPASS		BIT(21)
114 
115 #define SDEDM_WRITE_THRESHOLD_SHIFT	9
116 #define SDEDM_READ_THRESHOLD_SHIFT	14
117 #define SDEDM_THRESHOLD_MASK		0x1f
118 
119 #define SDEDM_FSM_MASK		0xf
120 #define SDEDM_FSM_IDENTMODE	0x0
121 #define SDEDM_FSM_DATAMODE	0x1
122 #define SDEDM_FSM_READDATA	0x2
123 #define SDEDM_FSM_WRITEDATA	0x3
124 #define SDEDM_FSM_READWAIT	0x4
125 #define SDEDM_FSM_READCRC	0x5
126 #define SDEDM_FSM_WRITECRC	0x6
127 #define SDEDM_FSM_WRITEWAIT1	0x7
128 #define SDEDM_FSM_POWERDOWN	0x8
129 #define SDEDM_FSM_POWERUP	0x9
130 #define SDEDM_FSM_WRITESTART1	0xa
131 #define SDEDM_FSM_WRITESTART2	0xb
132 #define SDEDM_FSM_GENPULSES	0xc
133 #define SDEDM_FSM_WRITEWAIT2	0xd
134 #define SDEDM_FSM_STARTPOWDOWN	0xf
135 
136 #define SDDATA_FIFO_WORDS	16
137 
138 #define FIFO_READ_THRESHOLD	4
139 #define FIFO_WRITE_THRESHOLD	4
140 #define SDDATA_FIFO_PIO_BURST	8
141 
142 #define PIO_THRESHOLD	1  /* Maximum block count for PIO (0 = always DMA) */
143 
144 struct bcm2835_host {
145 	spinlock_t		lock;
146 	struct mutex		mutex;
147 
148 	void __iomem		*ioaddr;
149 	u32			phys_addr;
150 
151 	struct clk		*clk;
152 	struct platform_device	*pdev;
153 
154 	unsigned int		clock;		/* Current clock speed */
155 	unsigned int		max_clk;	/* Max possible freq */
156 	struct work_struct	dma_work;
157 	struct delayed_work	timeout_work;	/* Timer for timeouts */
158 	struct sg_mapping_iter	sg_miter;	/* SG state for PIO */
159 	unsigned int		blocks;		/* remaining PIO blocks */
160 	int			irq;		/* Device IRQ */
161 
162 	u32			ns_per_fifo_word;
163 
164 	/* cached registers */
165 	u32			hcfg;
166 	u32			cdiv;
167 
168 	struct mmc_request	*mrq;		/* Current request */
169 	struct mmc_command	*cmd;		/* Current command */
170 	struct mmc_data		*data;		/* Current data request */
171 	bool			data_complete:1;/* Data finished before cmd */
172 	bool			use_busy:1;	/* Wait for busy interrupt */
173 	bool			use_sbc:1;	/* Send CMD23 */
174 
175 	/* for threaded irq handler */
176 	bool			irq_block;
177 	bool			irq_busy;
178 	bool			irq_data;
179 
180 	/* DMA part */
181 	struct dma_chan		*dma_chan_rxtx;
182 	struct dma_chan		*dma_chan;
183 	struct dma_slave_config dma_cfg_rx;
184 	struct dma_slave_config dma_cfg_tx;
185 	struct dma_async_tx_descriptor	*dma_desc;
186 	u32			dma_dir;
187 	u32			drain_words;
188 	struct page		*drain_page;
189 	u32			drain_offset;
190 	bool			use_dma;
191 };
192 
193 static void bcm2835_dumpcmd(struct bcm2835_host *host, struct mmc_command *cmd,
194 			    const char *label)
195 {
196 	struct device *dev = &host->pdev->dev;
197 
198 	if (!cmd)
199 		return;
200 
201 	dev_dbg(dev, "%c%s op %d arg 0x%x flags 0x%x - resp %08x %08x %08x %08x, err %d\n",
202 		(cmd == host->cmd) ? '>' : ' ',
203 		label, cmd->opcode, cmd->arg, cmd->flags,
204 		cmd->resp[0], cmd->resp[1], cmd->resp[2], cmd->resp[3],
205 		cmd->error);
206 }
207 
208 static void bcm2835_dumpregs(struct bcm2835_host *host)
209 {
210 	struct mmc_request *mrq = host->mrq;
211 	struct device *dev = &host->pdev->dev;
212 
213 	if (mrq) {
214 		bcm2835_dumpcmd(host, mrq->sbc, "sbc");
215 		bcm2835_dumpcmd(host, mrq->cmd, "cmd");
216 		if (mrq->data) {
217 			dev_dbg(dev, "data blocks %x blksz %x - err %d\n",
218 				mrq->data->blocks,
219 				mrq->data->blksz,
220 				mrq->data->error);
221 		}
222 		bcm2835_dumpcmd(host, mrq->stop, "stop");
223 	}
224 
225 	dev_dbg(dev, "=========== REGISTER DUMP ===========\n");
226 	dev_dbg(dev, "SDCMD  0x%08x\n", readl(host->ioaddr + SDCMD));
227 	dev_dbg(dev, "SDARG  0x%08x\n", readl(host->ioaddr + SDARG));
228 	dev_dbg(dev, "SDTOUT 0x%08x\n", readl(host->ioaddr + SDTOUT));
229 	dev_dbg(dev, "SDCDIV 0x%08x\n", readl(host->ioaddr + SDCDIV));
230 	dev_dbg(dev, "SDRSP0 0x%08x\n", readl(host->ioaddr + SDRSP0));
231 	dev_dbg(dev, "SDRSP1 0x%08x\n", readl(host->ioaddr + SDRSP1));
232 	dev_dbg(dev, "SDRSP2 0x%08x\n", readl(host->ioaddr + SDRSP2));
233 	dev_dbg(dev, "SDRSP3 0x%08x\n", readl(host->ioaddr + SDRSP3));
234 	dev_dbg(dev, "SDHSTS 0x%08x\n", readl(host->ioaddr + SDHSTS));
235 	dev_dbg(dev, "SDVDD  0x%08x\n", readl(host->ioaddr + SDVDD));
236 	dev_dbg(dev, "SDEDM  0x%08x\n", readl(host->ioaddr + SDEDM));
237 	dev_dbg(dev, "SDHCFG 0x%08x\n", readl(host->ioaddr + SDHCFG));
238 	dev_dbg(dev, "SDHBCT 0x%08x\n", readl(host->ioaddr + SDHBCT));
239 	dev_dbg(dev, "SDHBLC 0x%08x\n", readl(host->ioaddr + SDHBLC));
240 	dev_dbg(dev, "===========================================\n");
241 }
242 
243 static void bcm2835_reset_internal(struct bcm2835_host *host)
244 {
245 	u32 temp;
246 
247 	writel(SDVDD_POWER_OFF, host->ioaddr + SDVDD);
248 	writel(0, host->ioaddr + SDCMD);
249 	writel(0, host->ioaddr + SDARG);
250 	writel(0xf00000, host->ioaddr + SDTOUT);
251 	writel(0, host->ioaddr + SDCDIV);
252 	writel(0x7f8, host->ioaddr + SDHSTS); /* Write 1s to clear */
253 	writel(0, host->ioaddr + SDHCFG);
254 	writel(0, host->ioaddr + SDHBCT);
255 	writel(0, host->ioaddr + SDHBLC);
256 
257 	/* Limit fifo usage due to silicon bug */
258 	temp = readl(host->ioaddr + SDEDM);
259 	temp &= ~((SDEDM_THRESHOLD_MASK << SDEDM_READ_THRESHOLD_SHIFT) |
260 		  (SDEDM_THRESHOLD_MASK << SDEDM_WRITE_THRESHOLD_SHIFT));
261 	temp |= (FIFO_READ_THRESHOLD << SDEDM_READ_THRESHOLD_SHIFT) |
262 		(FIFO_WRITE_THRESHOLD << SDEDM_WRITE_THRESHOLD_SHIFT);
263 	writel(temp, host->ioaddr + SDEDM);
264 	msleep(20);
265 	writel(SDVDD_POWER_ON, host->ioaddr + SDVDD);
266 	msleep(20);
267 	host->clock = 0;
268 	writel(host->hcfg, host->ioaddr + SDHCFG);
269 	writel(host->cdiv, host->ioaddr + SDCDIV);
270 }
271 
272 static void bcm2835_reset(struct mmc_host *mmc)
273 {
274 	struct bcm2835_host *host = mmc_priv(mmc);
275 
276 	if (host->dma_chan)
277 		dmaengine_terminate_sync(host->dma_chan);
278 	host->dma_chan = NULL;
279 	bcm2835_reset_internal(host);
280 }
281 
282 static void bcm2835_finish_command(struct bcm2835_host *host);
283 
284 static void bcm2835_wait_transfer_complete(struct bcm2835_host *host)
285 {
286 	int timediff;
287 	u32 alternate_idle;
288 
289 	alternate_idle = (host->mrq->data->flags & MMC_DATA_READ) ?
290 		SDEDM_FSM_READWAIT : SDEDM_FSM_WRITESTART1;
291 
292 	timediff = 0;
293 
294 	while (1) {
295 		u32 edm, fsm;
296 
297 		edm = readl(host->ioaddr + SDEDM);
298 		fsm = edm & SDEDM_FSM_MASK;
299 
300 		if ((fsm == SDEDM_FSM_IDENTMODE) ||
301 		    (fsm == SDEDM_FSM_DATAMODE))
302 			break;
303 		if (fsm == alternate_idle) {
304 			writel(edm | SDEDM_FORCE_DATA_MODE,
305 			       host->ioaddr + SDEDM);
306 			break;
307 		}
308 
309 		timediff++;
310 		if (timediff == 100000) {
311 			dev_err(&host->pdev->dev,
312 				"wait_transfer_complete - still waiting after %d retries\n",
313 				timediff);
314 			bcm2835_dumpregs(host);
315 			host->mrq->data->error = -ETIMEDOUT;
316 			return;
317 		}
318 		cpu_relax();
319 	}
320 }
321 
322 static void bcm2835_dma_complete(void *param)
323 {
324 	struct bcm2835_host *host = param;
325 
326 	schedule_work(&host->dma_work);
327 }
328 
329 static void bcm2835_transfer_block_pio(struct bcm2835_host *host, bool is_read)
330 {
331 	size_t blksize;
332 	unsigned long wait_max;
333 
334 	blksize = host->data->blksz;
335 
336 	wait_max = jiffies + msecs_to_jiffies(500);
337 
338 	while (blksize) {
339 		int copy_words;
340 		u32 hsts = 0;
341 		size_t len;
342 		u32 *buf;
343 
344 		if (!sg_miter_next(&host->sg_miter)) {
345 			host->data->error = -EINVAL;
346 			break;
347 		}
348 
349 		len = min(host->sg_miter.length, blksize);
350 		if (len % 4) {
351 			host->data->error = -EINVAL;
352 			break;
353 		}
354 
355 		blksize -= len;
356 		host->sg_miter.consumed = len;
357 
358 		buf = (u32 *)host->sg_miter.addr;
359 
360 		copy_words = len / 4;
361 
362 		while (copy_words) {
363 			int burst_words, words;
364 			u32 edm;
365 
366 			burst_words = min(SDDATA_FIFO_PIO_BURST, copy_words);
367 			edm = readl(host->ioaddr + SDEDM);
368 			if (is_read)
369 				words = ((edm >> 4) & 0x1f);
370 			else
371 				words = SDDATA_FIFO_WORDS - ((edm >> 4) & 0x1f);
372 
373 			if (words < burst_words) {
374 				int fsm_state = (edm & SDEDM_FSM_MASK);
375 				struct device *dev = &host->pdev->dev;
376 
377 				if ((is_read &&
378 				     (fsm_state != SDEDM_FSM_READDATA &&
379 				      fsm_state != SDEDM_FSM_READWAIT &&
380 				      fsm_state != SDEDM_FSM_READCRC)) ||
381 				    (!is_read &&
382 				     (fsm_state != SDEDM_FSM_WRITEDATA &&
383 				      fsm_state != SDEDM_FSM_WRITESTART1 &&
384 				      fsm_state != SDEDM_FSM_WRITESTART2))) {
385 					hsts = readl(host->ioaddr + SDHSTS);
386 					dev_err(dev, "fsm %x, hsts %08x\n",
387 						fsm_state, hsts);
388 					if (hsts & SDHSTS_ERROR_MASK)
389 						break;
390 				}
391 
392 				if (time_after(jiffies, wait_max)) {
393 					dev_err(dev, "PIO %s timeout - EDM %08x\n",
394 						is_read ? "read" : "write",
395 						edm);
396 					hsts = SDHSTS_REW_TIME_OUT;
397 					break;
398 				}
399 				ndelay((burst_words - words) *
400 				       host->ns_per_fifo_word);
401 				continue;
402 			} else if (words > copy_words) {
403 				words = copy_words;
404 			}
405 
406 			copy_words -= words;
407 
408 			while (words) {
409 				if (is_read)
410 					*(buf++) = readl(host->ioaddr + SDDATA);
411 				else
412 					writel(*(buf++), host->ioaddr + SDDATA);
413 				words--;
414 			}
415 		}
416 
417 		if (hsts & SDHSTS_ERROR_MASK)
418 			break;
419 	}
420 
421 	sg_miter_stop(&host->sg_miter);
422 }
423 
424 static void bcm2835_transfer_pio(struct bcm2835_host *host)
425 {
426 	struct device *dev = &host->pdev->dev;
427 	u32 sdhsts;
428 	bool is_read;
429 
430 	is_read = (host->data->flags & MMC_DATA_READ) != 0;
431 	bcm2835_transfer_block_pio(host, is_read);
432 
433 	sdhsts = readl(host->ioaddr + SDHSTS);
434 	if (sdhsts & (SDHSTS_CRC16_ERROR |
435 		      SDHSTS_CRC7_ERROR |
436 		      SDHSTS_FIFO_ERROR)) {
437 		dev_err(dev, "%s transfer error - HSTS %08x\n",
438 			is_read ? "read" : "write", sdhsts);
439 		host->data->error = -EILSEQ;
440 	} else if ((sdhsts & (SDHSTS_CMD_TIME_OUT |
441 			      SDHSTS_REW_TIME_OUT))) {
442 		dev_err(dev, "%s timeout error - HSTS %08x\n",
443 			is_read ? "read" : "write", sdhsts);
444 		host->data->error = -ETIMEDOUT;
445 	}
446 }
447 
448 static
449 void bcm2835_prepare_dma(struct bcm2835_host *host, struct mmc_data *data)
450 {
451 	int sg_len, dir_data, dir_slave;
452 	struct dma_async_tx_descriptor *desc = NULL;
453 	struct dma_chan *dma_chan;
454 
455 	dma_chan = host->dma_chan_rxtx;
456 	if (data->flags & MMC_DATA_READ) {
457 		dir_data = DMA_FROM_DEVICE;
458 		dir_slave = DMA_DEV_TO_MEM;
459 	} else {
460 		dir_data = DMA_TO_DEVICE;
461 		dir_slave = DMA_MEM_TO_DEV;
462 	}
463 
464 	/* The block doesn't manage the FIFO DREQs properly for
465 	 * multi-block transfers, so don't attempt to DMA the final
466 	 * few words.  Unfortunately this requires the final sg entry
467 	 * to be trimmed.  N.B. This code demands that the overspill
468 	 * is contained in a single sg entry.
469 	 */
470 
471 	host->drain_words = 0;
472 	if ((data->blocks > 1) && (dir_data == DMA_FROM_DEVICE)) {
473 		struct scatterlist *sg;
474 		u32 len;
475 		int i;
476 
477 		len = min((u32)(FIFO_READ_THRESHOLD - 1) * 4,
478 			  (u32)data->blocks * data->blksz);
479 
480 		for_each_sg(data->sg, sg, data->sg_len, i) {
481 			if (sg_is_last(sg)) {
482 				WARN_ON(sg->length < len);
483 				sg->length -= len;
484 				host->drain_page = sg_page(sg);
485 				host->drain_offset = sg->offset + sg->length;
486 			}
487 		}
488 		host->drain_words = len / 4;
489 	}
490 
491 	/* The parameters have already been validated, so this will not fail */
492 	(void)dmaengine_slave_config(dma_chan,
493 				     (dir_data == DMA_FROM_DEVICE) ?
494 				     &host->dma_cfg_rx :
495 				     &host->dma_cfg_tx);
496 
497 	sg_len = dma_map_sg(dma_chan->device->dev, data->sg, data->sg_len,
498 			    dir_data);
499 	if (!sg_len)
500 		return;
501 
502 	desc = dmaengine_prep_slave_sg(dma_chan, data->sg, sg_len, dir_slave,
503 				       DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
504 
505 	if (!desc) {
506 		dma_unmap_sg(dma_chan->device->dev, data->sg, sg_len, dir_data);
507 		return;
508 	}
509 
510 	desc->callback = bcm2835_dma_complete;
511 	desc->callback_param = host;
512 	host->dma_desc = desc;
513 	host->dma_chan = dma_chan;
514 	host->dma_dir = dir_data;
515 }
516 
517 static void bcm2835_start_dma(struct bcm2835_host *host)
518 {
519 	dmaengine_submit(host->dma_desc);
520 	dma_async_issue_pending(host->dma_chan);
521 }
522 
523 static void bcm2835_set_transfer_irqs(struct bcm2835_host *host)
524 {
525 	u32 all_irqs = SDHCFG_DATA_IRPT_EN | SDHCFG_BLOCK_IRPT_EN |
526 		SDHCFG_BUSY_IRPT_EN;
527 
528 	if (host->dma_desc) {
529 		host->hcfg = (host->hcfg & ~all_irqs) |
530 			SDHCFG_BUSY_IRPT_EN;
531 	} else {
532 		host->hcfg = (host->hcfg & ~all_irqs) |
533 			SDHCFG_DATA_IRPT_EN |
534 			SDHCFG_BUSY_IRPT_EN;
535 	}
536 
537 	writel(host->hcfg, host->ioaddr + SDHCFG);
538 }
539 
540 static
541 void bcm2835_prepare_data(struct bcm2835_host *host, struct mmc_command *cmd)
542 {
543 	struct mmc_data *data = cmd->data;
544 
545 	WARN_ON(host->data);
546 
547 	host->data = data;
548 	if (!data)
549 		return;
550 
551 	host->data_complete = false;
552 	host->data->bytes_xfered = 0;
553 
554 	if (!host->dma_desc) {
555 		/* Use PIO */
556 		int flags = SG_MITER_ATOMIC;
557 
558 		if (data->flags & MMC_DATA_READ)
559 			flags |= SG_MITER_TO_SG;
560 		else
561 			flags |= SG_MITER_FROM_SG;
562 		sg_miter_start(&host->sg_miter, data->sg, data->sg_len, flags);
563 		host->blocks = data->blocks;
564 	}
565 
566 	bcm2835_set_transfer_irqs(host);
567 
568 	writel(data->blksz, host->ioaddr + SDHBCT);
569 	writel(data->blocks, host->ioaddr + SDHBLC);
570 }
571 
572 static u32 bcm2835_read_wait_sdcmd(struct bcm2835_host *host, u32 max_ms)
573 {
574 	struct device *dev = &host->pdev->dev;
575 	u32 value;
576 	int ret;
577 
578 	ret = readl_poll_timeout(host->ioaddr + SDCMD, value,
579 				 !(value & SDCMD_NEW_FLAG), 1, 10);
580 	if (ret == -ETIMEDOUT)
581 		/* if it takes a while make poll interval bigger */
582 		ret = readl_poll_timeout(host->ioaddr + SDCMD, value,
583 					 !(value & SDCMD_NEW_FLAG),
584 					 10, max_ms * 1000);
585 	if (ret == -ETIMEDOUT)
586 		dev_err(dev, "%s: timeout (%d ms)\n", __func__, max_ms);
587 
588 	return value;
589 }
590 
591 static void bcm2835_finish_request(struct bcm2835_host *host)
592 {
593 	struct dma_chan *terminate_chan = NULL;
594 	struct mmc_request *mrq;
595 
596 	cancel_delayed_work(&host->timeout_work);
597 
598 	mrq = host->mrq;
599 
600 	host->mrq = NULL;
601 	host->cmd = NULL;
602 	host->data = NULL;
603 
604 	host->dma_desc = NULL;
605 	terminate_chan = host->dma_chan;
606 	host->dma_chan = NULL;
607 
608 	if (terminate_chan) {
609 		int err = dmaengine_terminate_all(terminate_chan);
610 
611 		if (err)
612 			dev_err(&host->pdev->dev,
613 				"failed to terminate DMA (%d)\n", err);
614 	}
615 
616 	mmc_request_done(mmc_from_priv(host), mrq);
617 }
618 
619 static
620 bool bcm2835_send_command(struct bcm2835_host *host, struct mmc_command *cmd)
621 {
622 	struct device *dev = &host->pdev->dev;
623 	u32 sdcmd, sdhsts;
624 	unsigned long timeout;
625 
626 	WARN_ON(host->cmd);
627 
628 	sdcmd = bcm2835_read_wait_sdcmd(host, 100);
629 	if (sdcmd & SDCMD_NEW_FLAG) {
630 		dev_err(dev, "previous command never completed.\n");
631 		bcm2835_dumpregs(host);
632 		cmd->error = -EILSEQ;
633 		bcm2835_finish_request(host);
634 		return false;
635 	}
636 
637 	if (!cmd->data && cmd->busy_timeout > 9000)
638 		timeout = DIV_ROUND_UP(cmd->busy_timeout, 1000) * HZ + HZ;
639 	else
640 		timeout = 10 * HZ;
641 	schedule_delayed_work(&host->timeout_work, timeout);
642 
643 	host->cmd = cmd;
644 
645 	/* Clear any error flags */
646 	sdhsts = readl(host->ioaddr + SDHSTS);
647 	if (sdhsts & SDHSTS_ERROR_MASK)
648 		writel(sdhsts, host->ioaddr + SDHSTS);
649 
650 	if ((cmd->flags & MMC_RSP_136) && (cmd->flags & MMC_RSP_BUSY)) {
651 		dev_err(dev, "unsupported response type!\n");
652 		cmd->error = -EINVAL;
653 		bcm2835_finish_request(host);
654 		return false;
655 	}
656 
657 	bcm2835_prepare_data(host, cmd);
658 
659 	writel(cmd->arg, host->ioaddr + SDARG);
660 
661 	sdcmd = cmd->opcode & SDCMD_CMD_MASK;
662 
663 	host->use_busy = false;
664 	if (!(cmd->flags & MMC_RSP_PRESENT)) {
665 		sdcmd |= SDCMD_NO_RESPONSE;
666 	} else {
667 		if (cmd->flags & MMC_RSP_136)
668 			sdcmd |= SDCMD_LONG_RESPONSE;
669 		if (cmd->flags & MMC_RSP_BUSY) {
670 			sdcmd |= SDCMD_BUSYWAIT;
671 			host->use_busy = true;
672 		}
673 	}
674 
675 	if (cmd->data) {
676 		if (cmd->data->flags & MMC_DATA_WRITE)
677 			sdcmd |= SDCMD_WRITE_CMD;
678 		if (cmd->data->flags & MMC_DATA_READ)
679 			sdcmd |= SDCMD_READ_CMD;
680 	}
681 
682 	writel(sdcmd | SDCMD_NEW_FLAG, host->ioaddr + SDCMD);
683 
684 	return true;
685 }
686 
687 static void bcm2835_transfer_complete(struct bcm2835_host *host)
688 {
689 	struct mmc_data *data;
690 
691 	WARN_ON(!host->data_complete);
692 
693 	data = host->data;
694 	host->data = NULL;
695 
696 	/* Need to send CMD12 if -
697 	 * a) open-ended multiblock transfer (no CMD23)
698 	 * b) error in multiblock transfer
699 	 */
700 	if (host->mrq->stop && (data->error || !host->use_sbc)) {
701 		if (bcm2835_send_command(host, host->mrq->stop)) {
702 			/* No busy, so poll for completion */
703 			if (!host->use_busy)
704 				bcm2835_finish_command(host);
705 		}
706 	} else {
707 		bcm2835_wait_transfer_complete(host);
708 		bcm2835_finish_request(host);
709 	}
710 }
711 
712 static void bcm2835_finish_data(struct bcm2835_host *host)
713 {
714 	struct device *dev = &host->pdev->dev;
715 	struct mmc_data *data;
716 
717 	data = host->data;
718 
719 	host->hcfg &= ~(SDHCFG_DATA_IRPT_EN | SDHCFG_BLOCK_IRPT_EN);
720 	writel(host->hcfg, host->ioaddr + SDHCFG);
721 
722 	data->bytes_xfered = data->error ? 0 : (data->blksz * data->blocks);
723 
724 	host->data_complete = true;
725 
726 	if (host->cmd) {
727 		/* Data managed to finish before the
728 		 * command completed. Make sure we do
729 		 * things in the proper order.
730 		 */
731 		dev_dbg(dev, "Finished early - HSTS %08x\n",
732 			readl(host->ioaddr + SDHSTS));
733 	} else {
734 		bcm2835_transfer_complete(host);
735 	}
736 }
737 
738 static void bcm2835_finish_command(struct bcm2835_host *host)
739 {
740 	struct device *dev = &host->pdev->dev;
741 	struct mmc_command *cmd = host->cmd;
742 	u32 sdcmd;
743 
744 	sdcmd = bcm2835_read_wait_sdcmd(host, 100);
745 
746 	/* Check for errors */
747 	if (sdcmd & SDCMD_NEW_FLAG) {
748 		dev_err(dev, "command never completed.\n");
749 		bcm2835_dumpregs(host);
750 		host->cmd->error = -EIO;
751 		bcm2835_finish_request(host);
752 		return;
753 	} else if (sdcmd & SDCMD_FAIL_FLAG) {
754 		u32 sdhsts = readl(host->ioaddr + SDHSTS);
755 
756 		/* Clear the errors */
757 		writel(SDHSTS_ERROR_MASK, host->ioaddr + SDHSTS);
758 
759 		if (!(sdhsts & SDHSTS_CRC7_ERROR) ||
760 		    (host->cmd->opcode != MMC_SEND_OP_COND)) {
761 			u32 edm, fsm;
762 
763 			if (sdhsts & SDHSTS_CMD_TIME_OUT) {
764 				host->cmd->error = -ETIMEDOUT;
765 			} else {
766 				dev_err(dev, "unexpected command %d error\n",
767 					host->cmd->opcode);
768 				bcm2835_dumpregs(host);
769 				host->cmd->error = -EILSEQ;
770 			}
771 			edm = readl(host->ioaddr + SDEDM);
772 			fsm = edm & SDEDM_FSM_MASK;
773 			if (fsm == SDEDM_FSM_READWAIT ||
774 			    fsm == SDEDM_FSM_WRITESTART1)
775 				/* Kick the FSM out of its wait */
776 				writel(edm | SDEDM_FORCE_DATA_MODE,
777 				       host->ioaddr + SDEDM);
778 			bcm2835_finish_request(host);
779 			return;
780 		}
781 	}
782 
783 	if (cmd->flags & MMC_RSP_PRESENT) {
784 		if (cmd->flags & MMC_RSP_136) {
785 			int i;
786 
787 			for (i = 0; i < 4; i++) {
788 				cmd->resp[3 - i] =
789 					readl(host->ioaddr + SDRSP0 + i * 4);
790 			}
791 		} else {
792 			cmd->resp[0] = readl(host->ioaddr + SDRSP0);
793 		}
794 	}
795 
796 	if (cmd == host->mrq->sbc) {
797 		/* Finished CMD23, now send actual command. */
798 		host->cmd = NULL;
799 		if (bcm2835_send_command(host, host->mrq->cmd)) {
800 			if (host->data && host->dma_desc)
801 				/* DMA transfer starts now, PIO starts
802 				 * after irq
803 				 */
804 				bcm2835_start_dma(host);
805 
806 			if (!host->use_busy)
807 				bcm2835_finish_command(host);
808 		}
809 	} else if (cmd == host->mrq->stop) {
810 		/* Finished CMD12 */
811 		bcm2835_finish_request(host);
812 	} else {
813 		/* Processed actual command. */
814 		host->cmd = NULL;
815 		if (!host->data)
816 			bcm2835_finish_request(host);
817 		else if (host->data_complete)
818 			bcm2835_transfer_complete(host);
819 	}
820 }
821 
822 static void bcm2835_timeout(struct work_struct *work)
823 {
824 	struct delayed_work *d = to_delayed_work(work);
825 	struct bcm2835_host *host =
826 		container_of(d, struct bcm2835_host, timeout_work);
827 	struct device *dev = &host->pdev->dev;
828 
829 	mutex_lock(&host->mutex);
830 
831 	if (host->mrq) {
832 		dev_err(dev, "timeout waiting for hardware interrupt.\n");
833 		bcm2835_dumpregs(host);
834 
835 		bcm2835_reset(mmc_from_priv(host));
836 
837 		if (host->data) {
838 			host->data->error = -ETIMEDOUT;
839 			bcm2835_finish_data(host);
840 		} else {
841 			if (host->cmd)
842 				host->cmd->error = -ETIMEDOUT;
843 			else
844 				host->mrq->cmd->error = -ETIMEDOUT;
845 
846 			bcm2835_finish_request(host);
847 		}
848 	}
849 
850 	mutex_unlock(&host->mutex);
851 }
852 
853 static bool bcm2835_check_cmd_error(struct bcm2835_host *host, u32 intmask)
854 {
855 	struct device *dev = &host->pdev->dev;
856 
857 	if (!(intmask & SDHSTS_ERROR_MASK))
858 		return false;
859 
860 	if (!host->cmd)
861 		return true;
862 
863 	dev_err(dev, "sdhost_busy_irq: intmask %08x\n", intmask);
864 	if (intmask & SDHSTS_CRC7_ERROR) {
865 		host->cmd->error = -EILSEQ;
866 	} else if (intmask & (SDHSTS_CRC16_ERROR |
867 			      SDHSTS_FIFO_ERROR)) {
868 		if (host->mrq->data)
869 			host->mrq->data->error = -EILSEQ;
870 		else
871 			host->cmd->error = -EILSEQ;
872 	} else if (intmask & SDHSTS_REW_TIME_OUT) {
873 		if (host->mrq->data)
874 			host->mrq->data->error = -ETIMEDOUT;
875 		else
876 			host->cmd->error = -ETIMEDOUT;
877 	} else if (intmask & SDHSTS_CMD_TIME_OUT) {
878 		host->cmd->error = -ETIMEDOUT;
879 	}
880 	bcm2835_dumpregs(host);
881 	return true;
882 }
883 
884 static void bcm2835_check_data_error(struct bcm2835_host *host, u32 intmask)
885 {
886 	if (!host->data)
887 		return;
888 	if (intmask & (SDHSTS_CRC16_ERROR | SDHSTS_FIFO_ERROR))
889 		host->data->error = -EILSEQ;
890 	if (intmask & SDHSTS_REW_TIME_OUT)
891 		host->data->error = -ETIMEDOUT;
892 }
893 
894 static void bcm2835_busy_irq(struct bcm2835_host *host)
895 {
896 	if (WARN_ON(!host->cmd)) {
897 		bcm2835_dumpregs(host);
898 		return;
899 	}
900 
901 	if (WARN_ON(!host->use_busy)) {
902 		bcm2835_dumpregs(host);
903 		return;
904 	}
905 	host->use_busy = false;
906 
907 	bcm2835_finish_command(host);
908 }
909 
910 static void bcm2835_data_irq(struct bcm2835_host *host, u32 intmask)
911 {
912 	/* There are no dedicated data/space available interrupt
913 	 * status bits, so it is necessary to use the single shared
914 	 * data/space available FIFO status bits. It is therefore not
915 	 * an error to get here when there is no data transfer in
916 	 * progress.
917 	 */
918 	if (!host->data)
919 		return;
920 
921 	bcm2835_check_data_error(host, intmask);
922 	if (host->data->error)
923 		goto finished;
924 
925 	if (host->data->flags & MMC_DATA_WRITE) {
926 		/* Use the block interrupt for writes after the first block */
927 		host->hcfg &= ~(SDHCFG_DATA_IRPT_EN);
928 		host->hcfg |= SDHCFG_BLOCK_IRPT_EN;
929 		writel(host->hcfg, host->ioaddr + SDHCFG);
930 		bcm2835_transfer_pio(host);
931 	} else {
932 		bcm2835_transfer_pio(host);
933 		host->blocks--;
934 		if ((host->blocks == 0) || host->data->error)
935 			goto finished;
936 	}
937 	return;
938 
939 finished:
940 	host->hcfg &= ~(SDHCFG_DATA_IRPT_EN | SDHCFG_BLOCK_IRPT_EN);
941 	writel(host->hcfg, host->ioaddr + SDHCFG);
942 }
943 
944 static void bcm2835_data_threaded_irq(struct bcm2835_host *host)
945 {
946 	if (!host->data)
947 		return;
948 	if ((host->blocks == 0) || host->data->error)
949 		bcm2835_finish_data(host);
950 }
951 
952 static void bcm2835_block_irq(struct bcm2835_host *host)
953 {
954 	if (WARN_ON(!host->data)) {
955 		bcm2835_dumpregs(host);
956 		return;
957 	}
958 
959 	if (!host->dma_desc) {
960 		WARN_ON(!host->blocks);
961 		if (host->data->error || (--host->blocks == 0))
962 			bcm2835_finish_data(host);
963 		else
964 			bcm2835_transfer_pio(host);
965 	} else if (host->data->flags & MMC_DATA_WRITE) {
966 		bcm2835_finish_data(host);
967 	}
968 }
969 
970 static irqreturn_t bcm2835_irq(int irq, void *dev_id)
971 {
972 	irqreturn_t result = IRQ_NONE;
973 	struct bcm2835_host *host = dev_id;
974 	u32 intmask;
975 
976 	spin_lock(&host->lock);
977 
978 	intmask = readl(host->ioaddr + SDHSTS);
979 
980 	writel(SDHSTS_BUSY_IRPT |
981 	       SDHSTS_BLOCK_IRPT |
982 	       SDHSTS_SDIO_IRPT |
983 	       SDHSTS_DATA_FLAG,
984 	       host->ioaddr + SDHSTS);
985 
986 	if (intmask & SDHSTS_BLOCK_IRPT) {
987 		bcm2835_check_data_error(host, intmask);
988 		host->irq_block = true;
989 		result = IRQ_WAKE_THREAD;
990 	}
991 
992 	if (intmask & SDHSTS_BUSY_IRPT) {
993 		if (!bcm2835_check_cmd_error(host, intmask)) {
994 			host->irq_busy = true;
995 			result = IRQ_WAKE_THREAD;
996 		} else {
997 			result = IRQ_HANDLED;
998 		}
999 	}
1000 
1001 	/* There is no true data interrupt status bit, so it is
1002 	 * necessary to qualify the data flag with the interrupt
1003 	 * enable bit.
1004 	 */
1005 	if ((intmask & SDHSTS_DATA_FLAG) &&
1006 	    (host->hcfg & SDHCFG_DATA_IRPT_EN)) {
1007 		bcm2835_data_irq(host, intmask);
1008 		host->irq_data = true;
1009 		result = IRQ_WAKE_THREAD;
1010 	}
1011 
1012 	spin_unlock(&host->lock);
1013 
1014 	return result;
1015 }
1016 
1017 static irqreturn_t bcm2835_threaded_irq(int irq, void *dev_id)
1018 {
1019 	struct bcm2835_host *host = dev_id;
1020 	unsigned long flags;
1021 	bool block, busy, data;
1022 
1023 	spin_lock_irqsave(&host->lock, flags);
1024 
1025 	block = host->irq_block;
1026 	busy  = host->irq_busy;
1027 	data  = host->irq_data;
1028 	host->irq_block = false;
1029 	host->irq_busy  = false;
1030 	host->irq_data  = false;
1031 
1032 	spin_unlock_irqrestore(&host->lock, flags);
1033 
1034 	mutex_lock(&host->mutex);
1035 
1036 	if (block)
1037 		bcm2835_block_irq(host);
1038 	if (busy)
1039 		bcm2835_busy_irq(host);
1040 	if (data)
1041 		bcm2835_data_threaded_irq(host);
1042 
1043 	mutex_unlock(&host->mutex);
1044 
1045 	return IRQ_HANDLED;
1046 }
1047 
1048 static void bcm2835_dma_complete_work(struct work_struct *work)
1049 {
1050 	struct bcm2835_host *host =
1051 		container_of(work, struct bcm2835_host, dma_work);
1052 	struct mmc_data *data;
1053 
1054 	mutex_lock(&host->mutex);
1055 
1056 	data = host->data;
1057 
1058 	if (host->dma_chan) {
1059 		dma_unmap_sg(host->dma_chan->device->dev,
1060 			     data->sg, data->sg_len,
1061 			     host->dma_dir);
1062 
1063 		host->dma_chan = NULL;
1064 	}
1065 
1066 	if (host->drain_words) {
1067 		void *page;
1068 		u32 *buf;
1069 
1070 		if (host->drain_offset & PAGE_MASK) {
1071 			host->drain_page += host->drain_offset >> PAGE_SHIFT;
1072 			host->drain_offset &= ~PAGE_MASK;
1073 		}
1074 		page = kmap_local_page(host->drain_page);
1075 		buf = page + host->drain_offset;
1076 
1077 		while (host->drain_words) {
1078 			u32 edm = readl(host->ioaddr + SDEDM);
1079 
1080 			if ((edm >> 4) & 0x1f)
1081 				*(buf++) = readl(host->ioaddr + SDDATA);
1082 			host->drain_words--;
1083 		}
1084 
1085 		kunmap_local(page);
1086 	}
1087 
1088 	bcm2835_finish_data(host);
1089 
1090 	mutex_unlock(&host->mutex);
1091 }
1092 
1093 static void bcm2835_set_clock(struct bcm2835_host *host, unsigned int clock)
1094 {
1095 	struct mmc_host *mmc = mmc_from_priv(host);
1096 	int div;
1097 
1098 	/* The SDCDIV register has 11 bits, and holds (div - 2).  But
1099 	 * in data mode the max is 50MHz wihout a minimum, and only
1100 	 * the bottom 3 bits are used. Since the switch over is
1101 	 * automatic (unless we have marked the card as slow...),
1102 	 * chosen values have to make sense in both modes.  Ident mode
1103 	 * must be 100-400KHz, so can range check the requested
1104 	 * clock. CMD15 must be used to return to data mode, so this
1105 	 * can be monitored.
1106 	 *
1107 	 * clock 250MHz -> 0->125MHz, 1->83.3MHz, 2->62.5MHz, 3->50.0MHz
1108 	 *                 4->41.7MHz, 5->35.7MHz, 6->31.3MHz, 7->27.8MHz
1109 	 *
1110 	 *		 623->400KHz/27.8MHz
1111 	 *		 reset value (507)->491159/50MHz
1112 	 *
1113 	 * BUT, the 3-bit clock divisor in data mode is too small if
1114 	 * the core clock is higher than 250MHz, so instead use the
1115 	 * SLOW_CARD configuration bit to force the use of the ident
1116 	 * clock divisor at all times.
1117 	 */
1118 
1119 	if (clock < 100000) {
1120 		/* Can't stop the clock, but make it as slow as possible
1121 		 * to show willing
1122 		 */
1123 		host->cdiv = SDCDIV_MAX_CDIV;
1124 		writel(host->cdiv, host->ioaddr + SDCDIV);
1125 		return;
1126 	}
1127 
1128 	div = host->max_clk / clock;
1129 	if (div < 2)
1130 		div = 2;
1131 	if ((host->max_clk / div) > clock)
1132 		div++;
1133 	div -= 2;
1134 
1135 	if (div > SDCDIV_MAX_CDIV)
1136 		div = SDCDIV_MAX_CDIV;
1137 
1138 	clock = host->max_clk / (div + 2);
1139 	mmc->actual_clock = clock;
1140 
1141 	/* Calibrate some delays */
1142 
1143 	host->ns_per_fifo_word = (1000000000 / clock) *
1144 		((mmc->caps & MMC_CAP_4_BIT_DATA) ? 8 : 32);
1145 
1146 	host->cdiv = div;
1147 	writel(host->cdiv, host->ioaddr + SDCDIV);
1148 
1149 	/* Set the timeout to 500ms */
1150 	writel(mmc->actual_clock / 2, host->ioaddr + SDTOUT);
1151 }
1152 
1153 static void bcm2835_request(struct mmc_host *mmc, struct mmc_request *mrq)
1154 {
1155 	struct bcm2835_host *host = mmc_priv(mmc);
1156 	struct device *dev = &host->pdev->dev;
1157 	u32 edm, fsm;
1158 
1159 	/* Reset the error statuses in case this is a retry */
1160 	if (mrq->sbc)
1161 		mrq->sbc->error = 0;
1162 	if (mrq->cmd)
1163 		mrq->cmd->error = 0;
1164 	if (mrq->data)
1165 		mrq->data->error = 0;
1166 	if (mrq->stop)
1167 		mrq->stop->error = 0;
1168 
1169 	if (mrq->data && !is_power_of_2(mrq->data->blksz)) {
1170 		dev_err(dev, "unsupported block size (%d bytes)\n",
1171 			mrq->data->blksz);
1172 
1173 		if (mrq->cmd)
1174 			mrq->cmd->error = -EINVAL;
1175 
1176 		mmc_request_done(mmc, mrq);
1177 		return;
1178 	}
1179 
1180 	mutex_lock(&host->mutex);
1181 
1182 	WARN_ON(host->mrq);
1183 	host->mrq = mrq;
1184 
1185 	edm = readl(host->ioaddr + SDEDM);
1186 	fsm = edm & SDEDM_FSM_MASK;
1187 
1188 	if ((fsm != SDEDM_FSM_IDENTMODE) &&
1189 	    (fsm != SDEDM_FSM_DATAMODE)) {
1190 		dev_err(dev, "previous command (%d) not complete (EDM %08x)\n",
1191 			readl(host->ioaddr + SDCMD) & SDCMD_CMD_MASK,
1192 			edm);
1193 		bcm2835_dumpregs(host);
1194 
1195 		if (mrq->cmd)
1196 			mrq->cmd->error = -EILSEQ;
1197 
1198 		bcm2835_finish_request(host);
1199 		mutex_unlock(&host->mutex);
1200 		return;
1201 	}
1202 
1203 	if (host->use_dma && mrq->data && (mrq->data->blocks > PIO_THRESHOLD))
1204 		bcm2835_prepare_dma(host, mrq->data);
1205 
1206 	host->use_sbc = !!mrq->sbc && host->mrq->data &&
1207 			(host->mrq->data->flags & MMC_DATA_READ);
1208 	if (host->use_sbc) {
1209 		if (bcm2835_send_command(host, mrq->sbc)) {
1210 			if (!host->use_busy)
1211 				bcm2835_finish_command(host);
1212 		}
1213 	} else if (mrq->cmd && bcm2835_send_command(host, mrq->cmd)) {
1214 		if (host->data && host->dma_desc) {
1215 			/* DMA transfer starts now, PIO starts after irq */
1216 			bcm2835_start_dma(host);
1217 		}
1218 
1219 		if (!host->use_busy)
1220 			bcm2835_finish_command(host);
1221 	}
1222 
1223 	mutex_unlock(&host->mutex);
1224 }
1225 
1226 static void bcm2835_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
1227 {
1228 	struct bcm2835_host *host = mmc_priv(mmc);
1229 
1230 	mutex_lock(&host->mutex);
1231 
1232 	if (!ios->clock || ios->clock != host->clock) {
1233 		bcm2835_set_clock(host, ios->clock);
1234 		host->clock = ios->clock;
1235 	}
1236 
1237 	/* set bus width */
1238 	host->hcfg &= ~SDHCFG_WIDE_EXT_BUS;
1239 	if (ios->bus_width == MMC_BUS_WIDTH_4)
1240 		host->hcfg |= SDHCFG_WIDE_EXT_BUS;
1241 
1242 	host->hcfg |= SDHCFG_WIDE_INT_BUS;
1243 
1244 	/* Disable clever clock switching, to cope with fast core clocks */
1245 	host->hcfg |= SDHCFG_SLOW_CARD;
1246 
1247 	writel(host->hcfg, host->ioaddr + SDHCFG);
1248 
1249 	mutex_unlock(&host->mutex);
1250 }
1251 
1252 static const struct mmc_host_ops bcm2835_ops = {
1253 	.request = bcm2835_request,
1254 	.set_ios = bcm2835_set_ios,
1255 	.card_hw_reset = bcm2835_reset,
1256 };
1257 
1258 static int bcm2835_add_host(struct bcm2835_host *host)
1259 {
1260 	struct mmc_host *mmc = mmc_from_priv(host);
1261 	struct device *dev = &host->pdev->dev;
1262 	char pio_limit_string[20];
1263 	int ret;
1264 
1265 	if (!mmc->f_max || mmc->f_max > host->max_clk)
1266 		mmc->f_max = host->max_clk;
1267 	mmc->f_min = host->max_clk / SDCDIV_MAX_CDIV;
1268 
1269 	mmc->max_busy_timeout = ~0 / (mmc->f_max / 1000);
1270 
1271 	dev_dbg(dev, "f_max %d, f_min %d, max_busy_timeout %d\n",
1272 		mmc->f_max, mmc->f_min, mmc->max_busy_timeout);
1273 
1274 	/* host controller capabilities */
1275 	mmc->caps |= MMC_CAP_SD_HIGHSPEED | MMC_CAP_MMC_HIGHSPEED |
1276 		     MMC_CAP_NEEDS_POLL | MMC_CAP_HW_RESET | MMC_CAP_CMD23;
1277 
1278 	spin_lock_init(&host->lock);
1279 	mutex_init(&host->mutex);
1280 
1281 	if (!host->dma_chan_rxtx) {
1282 		dev_warn(dev, "unable to initialise DMA channel. Falling back to PIO\n");
1283 		host->use_dma = false;
1284 	} else {
1285 		host->use_dma = true;
1286 
1287 		host->dma_cfg_tx.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1288 		host->dma_cfg_tx.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1289 		host->dma_cfg_tx.direction = DMA_MEM_TO_DEV;
1290 		host->dma_cfg_tx.src_addr = 0;
1291 		host->dma_cfg_tx.dst_addr = host->phys_addr + SDDATA;
1292 
1293 		host->dma_cfg_rx.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1294 		host->dma_cfg_rx.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
1295 		host->dma_cfg_rx.direction = DMA_DEV_TO_MEM;
1296 		host->dma_cfg_rx.src_addr = host->phys_addr + SDDATA;
1297 		host->dma_cfg_rx.dst_addr = 0;
1298 
1299 		if (dmaengine_slave_config(host->dma_chan_rxtx,
1300 					   &host->dma_cfg_tx) != 0 ||
1301 		    dmaengine_slave_config(host->dma_chan_rxtx,
1302 					   &host->dma_cfg_rx) != 0)
1303 			host->use_dma = false;
1304 	}
1305 
1306 	mmc->max_segs = 128;
1307 	mmc->max_req_size = min_t(size_t, 524288, dma_max_mapping_size(dev));
1308 	mmc->max_seg_size = mmc->max_req_size;
1309 	mmc->max_blk_size = 1024;
1310 	mmc->max_blk_count =  65535;
1311 
1312 	/* report supported voltage ranges */
1313 	mmc->ocr_avail = MMC_VDD_32_33 | MMC_VDD_33_34;
1314 
1315 	INIT_WORK(&host->dma_work, bcm2835_dma_complete_work);
1316 	INIT_DELAYED_WORK(&host->timeout_work, bcm2835_timeout);
1317 
1318 	/* Set interrupt enables */
1319 	host->hcfg = SDHCFG_BUSY_IRPT_EN;
1320 
1321 	bcm2835_reset_internal(host);
1322 
1323 	ret = request_threaded_irq(host->irq, bcm2835_irq,
1324 				   bcm2835_threaded_irq,
1325 				   0, mmc_hostname(mmc), host);
1326 	if (ret) {
1327 		dev_err(dev, "failed to request IRQ %d: %d\n", host->irq, ret);
1328 		return ret;
1329 	}
1330 
1331 	ret = mmc_add_host(mmc);
1332 	if (ret) {
1333 		free_irq(host->irq, host);
1334 		return ret;
1335 	}
1336 
1337 	pio_limit_string[0] = '\0';
1338 	if (host->use_dma && (PIO_THRESHOLD > 0))
1339 		sprintf(pio_limit_string, " (>%d)", PIO_THRESHOLD);
1340 	dev_info(dev, "loaded - DMA %s%s\n",
1341 		 host->use_dma ? "enabled" : "disabled", pio_limit_string);
1342 
1343 	return 0;
1344 }
1345 
1346 static int bcm2835_probe(struct platform_device *pdev)
1347 {
1348 	struct device *dev = &pdev->dev;
1349 	struct bcm2835_host *host;
1350 	struct mmc_host *mmc;
1351 	const __be32 *regaddr_p;
1352 	int ret;
1353 
1354 	dev_dbg(dev, "%s\n", __func__);
1355 	mmc = mmc_alloc_host(sizeof(*host), dev);
1356 	if (!mmc)
1357 		return -ENOMEM;
1358 
1359 	mmc->ops = &bcm2835_ops;
1360 	host = mmc_priv(mmc);
1361 	host->pdev = pdev;
1362 	spin_lock_init(&host->lock);
1363 
1364 	host->ioaddr = devm_platform_ioremap_resource(pdev, 0);
1365 	if (IS_ERR(host->ioaddr)) {
1366 		ret = PTR_ERR(host->ioaddr);
1367 		goto err;
1368 	}
1369 
1370 	/* Parse OF address directly to get the physical address for
1371 	 * DMA to our registers.
1372 	 */
1373 	regaddr_p = of_get_address(pdev->dev.of_node, 0, NULL, NULL);
1374 	if (!regaddr_p) {
1375 		dev_err(dev, "Can't get phys address\n");
1376 		ret = -EINVAL;
1377 		goto err;
1378 	}
1379 
1380 	host->phys_addr = be32_to_cpup(regaddr_p);
1381 
1382 	host->dma_chan = NULL;
1383 	host->dma_desc = NULL;
1384 
1385 	host->dma_chan_rxtx = dma_request_chan(dev, "rx-tx");
1386 	if (IS_ERR(host->dma_chan_rxtx)) {
1387 		ret = PTR_ERR(host->dma_chan_rxtx);
1388 		host->dma_chan_rxtx = NULL;
1389 
1390 		if (ret == -EPROBE_DEFER)
1391 			goto err;
1392 
1393 		/* Ignore errors to fall back to PIO mode */
1394 	}
1395 
1396 	host->irq = platform_get_irq(pdev, 0);
1397 	if (host->irq < 0) {
1398 		ret = host->irq;
1399 		goto err;
1400 	}
1401 
1402 	ret = mmc_of_parse(mmc);
1403 	if (ret)
1404 		goto err;
1405 
1406 	host->clk = devm_clk_get(dev, NULL);
1407 	if (IS_ERR(host->clk)) {
1408 		ret = dev_err_probe(dev, PTR_ERR(host->clk), "could not get clk\n");
1409 		goto err;
1410 	}
1411 
1412 	ret = clk_prepare_enable(host->clk);
1413 	if (ret)
1414 		goto err;
1415 
1416 	host->max_clk = clk_get_rate(host->clk);
1417 
1418 	ret = bcm2835_add_host(host);
1419 	if (ret)
1420 		goto err_clk;
1421 
1422 	platform_set_drvdata(pdev, host);
1423 
1424 	dev_dbg(dev, "%s -> OK\n", __func__);
1425 
1426 	return 0;
1427 
1428 err_clk:
1429 	clk_disable_unprepare(host->clk);
1430 err:
1431 	dev_dbg(dev, "%s -> err %d\n", __func__, ret);
1432 	if (host->dma_chan_rxtx)
1433 		dma_release_channel(host->dma_chan_rxtx);
1434 	mmc_free_host(mmc);
1435 
1436 	return ret;
1437 }
1438 
1439 static void bcm2835_remove(struct platform_device *pdev)
1440 {
1441 	struct bcm2835_host *host = platform_get_drvdata(pdev);
1442 	struct mmc_host *mmc = mmc_from_priv(host);
1443 
1444 	mmc_remove_host(mmc);
1445 
1446 	writel(SDVDD_POWER_OFF, host->ioaddr + SDVDD);
1447 
1448 	free_irq(host->irq, host);
1449 
1450 	cancel_work_sync(&host->dma_work);
1451 	cancel_delayed_work_sync(&host->timeout_work);
1452 
1453 	clk_disable_unprepare(host->clk);
1454 
1455 	if (host->dma_chan_rxtx)
1456 		dma_release_channel(host->dma_chan_rxtx);
1457 
1458 	mmc_free_host(mmc);
1459 }
1460 
1461 static const struct of_device_id bcm2835_match[] = {
1462 	{ .compatible = "brcm,bcm2835-sdhost" },
1463 	{ }
1464 };
1465 MODULE_DEVICE_TABLE(of, bcm2835_match);
1466 
1467 static struct platform_driver bcm2835_driver = {
1468 	.probe      = bcm2835_probe,
1469 	.remove     = bcm2835_remove,
1470 	.driver     = {
1471 		.name		= "sdhost-bcm2835",
1472 		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
1473 		.of_match_table	= bcm2835_match,
1474 	},
1475 };
1476 module_platform_driver(bcm2835_driver);
1477 
1478 MODULE_ALIAS("platform:sdhost-bcm2835");
1479 MODULE_DESCRIPTION("BCM2835 SDHost driver");
1480 MODULE_LICENSE("GPL v2");
1481 MODULE_AUTHOR("Phil Elwell");
1482