2 * linux/drivers/mmc/tmio_mmc_dma.c
4 * Copyright (C) 2010-2011 Guennadi Liakhovetski
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.
10 * DMA function for TMIO MMC implementations
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>
24 #define TMIO_MMC_MIN_DMA_LEN 8
26 void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
28 if (!host->chan_tx || !host->chan_rx)
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);
37 static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
39 struct scatterlist *sg = host->sg_ptr, *sg_tmp;
40 struct dma_async_tx_descriptor *desc = NULL;
41 struct dma_chan *chan = host->chan_rx;
42 struct tmio_mmc_data *pdata = host->pdata;
45 bool aligned = true, multiple = true;
46 unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
48 for_each_sg(sg, sg_tmp, host->sg_len, i) {
49 if (sg_tmp->offset & align)
51 if (sg_tmp->length & align) {
57 if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
58 (align & PAGE_MASK))) || !multiple) {
63 if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
64 host->force_pio = true;
68 tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
70 /* The only sg element can be unaligned, use our bounce buffer then */
72 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
73 host->sg_ptr = &host->bounce_sg;
77 ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
79 desc = chan->device->device_prep_slave_sg(chan, sg, ret,
80 DMA_FROM_DEVICE, DMA_CTRL_ACK);
83 cookie = dmaengine_submit(desc);
89 dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
90 __func__, host->sg_len, ret, cookie, host->mrq);
94 /* DMA failed, fall back to PIO */
98 dma_release_channel(chan);
99 /* Free the Tx channel too */
100 chan = host->chan_tx;
102 host->chan_tx = NULL;
103 dma_release_channel(chan);
105 dev_warn(&host->pdev->dev,
106 "DMA failed: %d, falling back to PIO\n", ret);
107 tmio_mmc_enable_dma(host, false);
110 dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
111 desc, cookie, host->sg_len);
114 static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
116 struct scatterlist *sg = host->sg_ptr, *sg_tmp;
117 struct dma_async_tx_descriptor *desc = NULL;
118 struct dma_chan *chan = host->chan_tx;
119 struct tmio_mmc_data *pdata = host->pdata;
122 bool aligned = true, multiple = true;
123 unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
125 for_each_sg(sg, sg_tmp, host->sg_len, i) {
126 if (sg_tmp->offset & align)
128 if (sg_tmp->length & align) {
134 if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
135 (align & PAGE_MASK))) || !multiple) {
140 if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
141 host->force_pio = true;
145 tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
147 /* The only sg element can be unaligned, use our bounce buffer then */
150 void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
151 sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
152 memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
153 tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
154 host->sg_ptr = &host->bounce_sg;
158 ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
160 desc = chan->device->device_prep_slave_sg(chan, sg, ret,
161 DMA_TO_DEVICE, DMA_CTRL_ACK);
164 cookie = dmaengine_submit(desc);
170 dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
171 __func__, host->sg_len, ret, cookie, host->mrq);
175 /* DMA failed, fall back to PIO */
178 host->chan_tx = NULL;
179 dma_release_channel(chan);
180 /* Free the Rx channel too */
181 chan = host->chan_rx;
183 host->chan_rx = NULL;
184 dma_release_channel(chan);
186 dev_warn(&host->pdev->dev,
187 "DMA failed: %d, falling back to PIO\n", ret);
188 tmio_mmc_enable_dma(host, false);
191 dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,
195 void tmio_mmc_start_dma(struct tmio_mmc_host *host,
196 struct mmc_data *data)
198 if (data->flags & MMC_DATA_READ) {
200 tmio_mmc_start_dma_rx(host);
203 tmio_mmc_start_dma_tx(host);
207 static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
209 struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
210 struct dma_chan *chan = NULL;
212 spin_lock_irq(&host->lock);
214 if (host && host->data) {
215 if (host->data->flags & MMC_DATA_READ)
216 chan = host->chan_rx;
218 chan = host->chan_tx;
221 spin_unlock_irq(&host->lock);
223 tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
226 dma_async_issue_pending(chan);
229 static void tmio_mmc_tasklet_fn(unsigned long arg)
231 struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
233 spin_lock_irq(&host->lock);
238 if (host->data->flags & MMC_DATA_READ)
239 dma_unmap_sg(host->chan_rx->device->dev,
240 host->sg_ptr, host->sg_len,
243 dma_unmap_sg(host->chan_tx->device->dev,
244 host->sg_ptr, host->sg_len,
247 tmio_mmc_do_data_irq(host);
249 spin_unlock_irq(&host->lock);
252 /* It might be necessary to make filter MFD specific */
253 static bool tmio_mmc_filter(struct dma_chan *chan, void *arg)
255 dev_dbg(chan->device->dev, "%s: slave data %p\n", __func__, arg);
260 void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
262 /* We can only either use DMA for both Tx and Rx or not use it at all */
266 if (!host->chan_tx && !host->chan_rx) {
270 dma_cap_set(DMA_SLAVE, mask);
272 host->chan_tx = dma_request_channel(mask, tmio_mmc_filter,
273 pdata->dma->chan_priv_tx);
274 dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
280 host->chan_rx = dma_request_channel(mask, tmio_mmc_filter,
281 pdata->dma->chan_priv_rx);
282 dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
288 host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
289 if (!host->bounce_buf)
292 tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
293 tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
296 tmio_mmc_enable_dma(host, true);
301 dma_release_channel(host->chan_rx);
302 host->chan_rx = NULL;
304 dma_release_channel(host->chan_tx);
305 host->chan_tx = NULL;
308 void tmio_mmc_release_dma(struct tmio_mmc_host *host)
311 struct dma_chan *chan = host->chan_tx;
312 host->chan_tx = NULL;
313 dma_release_channel(chan);
316 struct dma_chan *chan = host->chan_rx;
317 host->chan_rx = NULL;
318 dma_release_channel(chan);
320 if (host->bounce_buf) {
321 free_pages((unsigned long)host->bounce_buf, 0);
322 host->bounce_buf = NULL;