fff9286048594fa7dad59922ea382af76901450b
[linux-2.6.git] / drivers / mmc / host / tmio_mmc_dma.c
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
26 void 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
37 void 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
49 static 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
104 pio:
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
126 static 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
185 pio:
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
207 void 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
219 static 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
241 static 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);
260 out:
261         spin_unlock_irq(&host->lock);
262 }
263
264 /* It might be necessary to make filter MFD specific */
265 static 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
272 void 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
312 ebouncebuf:
313         dma_release_channel(host->chan_rx);
314         host->chan_rx = NULL;
315 ereqrx:
316         dma_release_channel(host->chan_tx);
317         host->chan_tx = NULL;
318 }
319
320 void 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 }