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
tmio_mmc_enable_dma(struct tmio_mmc_host * host,bool enable)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
tmio_mmc_abort_dma(struct tmio_mmc_host * host)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
tmio_mmc_start_dma_rx(struct tmio_mmc_host * host)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 = chan->device->device_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
tmio_mmc_start_dma_tx(struct tmio_mmc_host * host)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 = chan->device->device_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
tmio_mmc_start_dma(struct tmio_mmc_host * host,struct mmc_data * data)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
tmio_mmc_issue_tasklet_fn(unsigned long priv)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
tmio_mmc_tasklet_fn(unsigned long arg)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 */
tmio_mmc_filter(struct dma_chan * chan,void * arg)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
tmio_mmc_request_dma(struct tmio_mmc_host * host,struct tmio_mmc_data * pdata)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
tmio_mmc_release_dma(struct tmio_mmc_host * host)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 }
337