1/*
  2 * linux/drivers/mmc/tmio_mmc_dma.c
  3 *
  4 * Copyright (C) 2010-2011 Guennadi Liakhovetski
  5 *
  6 * This program is free software; you can redistribute it and/or modify
  7 * it under the terms of the GNU General Public License version 2 as
  8 * published by the Free Software Foundation.
  9 *
 10 * DMA function for TMIO MMC implementations
 11 */
 12
 13#include <linux/device.h>
 14#include <linux/dma-mapping.h>
 15#include <linux/dmaengine.h>
 16#include <linux/mfd/tmio.h>
 17#include <linux/mmc/host.h>
 18#include <linux/mmc/tmio.h>
 19#include <linux/pagemap.h>
 20#include <linux/scatterlist.h>
 21
 22#include "tmio_mmc.h"
 23
 24#define TMIO_MMC_MIN_DMA_LEN 8
 25
 26void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
 27{
 28	if (!host->chan_tx || !host->chan_rx)
 29		return;
 30
 31#if defined(CONFIG_SUPERH) || defined(CONFIG_ARCH_SHMOBILE)
 32	/* Switch DMA mode on or off - SuperH specific? */
 33	sd_ctrl_write16(host, CTL_DMA_ENABLE, enable ? 2 : 0);
 34#endif
 35}
 36
 37void tmio_mmc_abort_dma(struct tmio_mmc_host *host)
 38{
 39	tmio_mmc_enable_dma(host, false);
 40
 41	if (host->chan_rx)
 42		dmaengine_terminate_all(host->chan_rx);
 43	if (host->chan_tx)
 44		dmaengine_terminate_all(host->chan_tx);
 45
 46	tmio_mmc_enable_dma(host, true);
 47}
 48
 49static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
 50{
 51	struct scatterlist *sg = host->sg_ptr, *sg_tmp;
 52	struct dma_async_tx_descriptor *desc = NULL;
 53	struct dma_chan *chan = host->chan_rx;
 54	struct tmio_mmc_data *pdata = host->pdata;
 55	dma_cookie_t cookie;
 56	int ret, i;
 57	bool aligned = true, multiple = true;
 58	unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
 59
 60	for_each_sg(sg, sg_tmp, host->sg_len, i) {
 61		if (sg_tmp->offset & align)
 62			aligned = false;
 63		if (sg_tmp->length & align) {
 64			multiple = false;
 65			break;
 66		}
 67	}
 68
 69	if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
 70			  (align & PAGE_MASK))) || !multiple) {
 71		ret = -EINVAL;
 72		goto pio;
 73	}
 74
 75	if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
 76		host->force_pio = true;
 77		return;
 78	}
 79
 80	tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
 81
 82	/* The only sg element can be unaligned, use our bounce buffer then */
 83	if (!aligned) {
 84		sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
 85		host->sg_ptr = &host->bounce_sg;
 86		sg = host->sg_ptr;
 87	}
 88
 89	ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
 90	if (ret > 0)
 91		desc = dmaengine_prep_slave_sg(chan, sg, ret,
 92			DMA_DEV_TO_MEM, DMA_CTRL_ACK);
 93
 94	if (desc) {
 95		cookie = dmaengine_submit(desc);
 96		if (cookie < 0) {
 97			desc = NULL;
 98			ret = cookie;
 99		}
100	}
101	dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
102		__func__, host->sg_len, ret, cookie, host->mrq);
103
104pio:
105	if (!desc) {
106		/* DMA failed, fall back to PIO */
107		if (ret >= 0)
108			ret = -EIO;
109		host->chan_rx = NULL;
110		dma_release_channel(chan);
111		/* Free the Tx channel too */
112		chan = host->chan_tx;
113		if (chan) {
114			host->chan_tx = NULL;
115			dma_release_channel(chan);
116		}
117		dev_warn(&host->pdev->dev,
118			 "DMA failed: %d, falling back to PIO\n", ret);
119		tmio_mmc_enable_dma(host, false);
120	}
121
122	dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
123		desc, cookie, host->sg_len);
124}
125
126static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
127{
128	struct scatterlist *sg = host->sg_ptr, *sg_tmp;
129	struct dma_async_tx_descriptor *desc = NULL;
130	struct dma_chan *chan = host->chan_tx;
131	struct tmio_mmc_data *pdata = host->pdata;
132	dma_cookie_t cookie;
133	int ret, i;
134	bool aligned = true, multiple = true;
135	unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
136
137	for_each_sg(sg, sg_tmp, host->sg_len, i) {
138		if (sg_tmp->offset & align)
139			aligned = false;
140		if (sg_tmp->length & align) {
141			multiple = false;
142			break;
143		}
144	}
145
146	if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
147			  (align & PAGE_MASK))) || !multiple) {
148		ret = -EINVAL;
149		goto pio;
150	}
151
152	if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
153		host->force_pio = true;
154		return;
155	}
156
157	tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
158
159	/* The only sg element can be unaligned, use our bounce buffer then */
160	if (!aligned) {
161		unsigned long flags;
162		void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
163		sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
164		memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
165		tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
166		host->sg_ptr = &host->bounce_sg;
167		sg = host->sg_ptr;
168	}
169
170	ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
171	if (ret > 0)
172		desc = dmaengine_prep_slave_sg(chan, sg, ret,
173			DMA_MEM_TO_DEV, DMA_CTRL_ACK);
174
175	if (desc) {
176		cookie = dmaengine_submit(desc);
177		if (cookie < 0) {
178			desc = NULL;
179			ret = cookie;
180		}
181	}
182	dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
183		__func__, host->sg_len, ret, cookie, host->mrq);
184
185pio:
186	if (!desc) {
187		/* DMA failed, fall back to PIO */
188		if (ret >= 0)
189			ret = -EIO;
190		host->chan_tx = NULL;
191		dma_release_channel(chan);
192		/* Free the Rx channel too */
193		chan = host->chan_rx;
194		if (chan) {
195			host->chan_rx = NULL;
196			dma_release_channel(chan);
197		}
198		dev_warn(&host->pdev->dev,
199			 "DMA failed: %d, falling back to PIO\n", ret);
200		tmio_mmc_enable_dma(host, false);
201	}
202
203	dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,
204		desc, cookie);
205}
206
207void tmio_mmc_start_dma(struct tmio_mmc_host *host,
208			       struct mmc_data *data)
209{
210	if (data->flags & MMC_DATA_READ) {
211		if (host->chan_rx)
212			tmio_mmc_start_dma_rx(host);
213	} else {
214		if (host->chan_tx)
215			tmio_mmc_start_dma_tx(host);
216	}
217}
218
219static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
220{
221	struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
222	struct dma_chan *chan = NULL;
223
224	spin_lock_irq(&host->lock);
225
226	if (host && host->data) {
227		if (host->data->flags & MMC_DATA_READ)
228			chan = host->chan_rx;
229		else
230			chan = host->chan_tx;
231	}
232
233	spin_unlock_irq(&host->lock);
234
235	tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
236
237	if (chan)
238		dma_async_issue_pending(chan);
239}
240
241static void tmio_mmc_tasklet_fn(unsigned long arg)
242{
243	struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
244
245	spin_lock_irq(&host->lock);
246
247	if (!host->data)
248		goto out;
249
250	if (host->data->flags & MMC_DATA_READ)
251		dma_unmap_sg(host->chan_rx->device->dev,
252			     host->sg_ptr, host->sg_len,
253			     DMA_FROM_DEVICE);
254	else
255		dma_unmap_sg(host->chan_tx->device->dev,
256			     host->sg_ptr, host->sg_len,
257			     DMA_TO_DEVICE);
258
259	tmio_mmc_do_data_irq(host);
260out:
261	spin_unlock_irq(&host->lock);
262}
263
264/* It might be necessary to make filter MFD specific */
265static bool tmio_mmc_filter(struct dma_chan *chan, void *arg)
266{
267	dev_dbg(chan->device->dev, "%s: slave data %p\n", __func__, arg);
268	chan->private = arg;
269	return true;
270}
271
272void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
273{
274	/* We can only either use DMA for both Tx and Rx or not use it at all */
275	if (!pdata->dma)
276		return;
277
278	if (!host->chan_tx && !host->chan_rx) {
279		dma_cap_mask_t mask;
280
281		dma_cap_zero(mask);
282		dma_cap_set(DMA_SLAVE, mask);
283
284		host->chan_tx = dma_request_channel(mask, tmio_mmc_filter,
285						    pdata->dma->chan_priv_tx);
286		dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
287			host->chan_tx);
288
289		if (!host->chan_tx)
290			return;
291
292		host->chan_rx = dma_request_channel(mask, tmio_mmc_filter,
293						    pdata->dma->chan_priv_rx);
294		dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
295			host->chan_rx);
296
297		if (!host->chan_rx)
298			goto ereqrx;
299
300		host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
301		if (!host->bounce_buf)
302			goto ebouncebuf;
303
304		tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
305		tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
306	}
307
308	tmio_mmc_enable_dma(host, true);
309
310	return;
311
312ebouncebuf:
313	dma_release_channel(host->chan_rx);
314	host->chan_rx = NULL;
315ereqrx:
316	dma_release_channel(host->chan_tx);
317	host->chan_tx = NULL;
318}
319
320void tmio_mmc_release_dma(struct tmio_mmc_host *host)
321{
322	if (host->chan_tx) {
323		struct dma_chan *chan = host->chan_tx;
324		host->chan_tx = NULL;
325		dma_release_channel(chan);
326	}
327	if (host->chan_rx) {
328		struct dma_chan *chan = host->chan_rx;
329		host->chan_rx = NULL;
330		dma_release_channel(chan);
331	}
332	if (host->bounce_buf) {
333		free_pages((unsigned long)host->bounce_buf, 0);
334		host->bounce_buf = NULL;
335	}
336}