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path: root/drivers/mmc/host/tmio_mmc_dma.c
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Diffstat (limited to 'drivers/mmc/host/tmio_mmc_dma.c')
-rw-r--r--drivers/mmc/host/tmio_mmc_dma.c317
1 files changed, 317 insertions, 0 deletions
diff --git a/drivers/mmc/host/tmio_mmc_dma.c b/drivers/mmc/host/tmio_mmc_dma.c
new file mode 100644
index 000000000000..d3de74ab633e
--- /dev/null
+++ b/drivers/mmc/host/tmio_mmc_dma.c
@@ -0,0 +1,317 @@
+/*
+ * linux/drivers/mmc/tmio_mmc_dma.c
+ *
+ * Copyright (C) 2010-2011 Guennadi Liakhovetski
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * DMA function for TMIO MMC implementations
+ */
+
+#include <linux/device.h>
+#include <linux/dmaengine.h>
+#include <linux/mfd/tmio.h>
+#include <linux/mmc/host.h>
+#include <linux/mmc/tmio.h>
+#include <linux/pagemap.h>
+#include <linux/scatterlist.h>
+
+#include "tmio_mmc.h"
+
+#define TMIO_MMC_MIN_DMA_LEN 8
+
+static void tmio_mmc_enable_dma(struct tmio_mmc_host *host, bool enable)
+{
+#if defined(CONFIG_SUPERH) || defined(CONFIG_ARCH_SHMOBILE)
+ /* Switch DMA mode on or off - SuperH specific? */
+ writew(enable ? 2 : 0, host->ctl + (0xd8 << host->bus_shift));
+#endif
+}
+
+static void tmio_mmc_start_dma_rx(struct tmio_mmc_host *host)
+{
+ struct scatterlist *sg = host->sg_ptr, *sg_tmp;
+ struct dma_async_tx_descriptor *desc = NULL;
+ struct dma_chan *chan = host->chan_rx;
+ struct tmio_mmc_data *pdata = host->pdata;
+ dma_cookie_t cookie;
+ int ret, i;
+ bool aligned = true, multiple = true;
+ unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
+
+ for_each_sg(sg, sg_tmp, host->sg_len, i) {
+ if (sg_tmp->offset & align)
+ aligned = false;
+ if (sg_tmp->length & align) {
+ multiple = false;
+ break;
+ }
+ }
+
+ if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
+ (align & PAGE_MASK))) || !multiple) {
+ ret = -EINVAL;
+ goto pio;
+ }
+
+ if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
+ host->force_pio = true;
+ return;
+ }
+
+ tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_RXRDY);
+
+ /* The only sg element can be unaligned, use our bounce buffer then */
+ if (!aligned) {
+ sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
+ host->sg_ptr = &host->bounce_sg;
+ sg = host->sg_ptr;
+ }
+
+ ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_FROM_DEVICE);
+ if (ret > 0)
+ desc = chan->device->device_prep_slave_sg(chan, sg, ret,
+ DMA_FROM_DEVICE, DMA_CTRL_ACK);
+
+ if (desc) {
+ cookie = dmaengine_submit(desc);
+ if (cookie < 0) {
+ desc = NULL;
+ ret = cookie;
+ }
+ }
+ dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
+ __func__, host->sg_len, ret, cookie, host->mrq);
+
+pio:
+ if (!desc) {
+ /* DMA failed, fall back to PIO */
+ if (ret >= 0)
+ ret = -EIO;
+ host->chan_rx = NULL;
+ dma_release_channel(chan);
+ /* Free the Tx channel too */
+ chan = host->chan_tx;
+ if (chan) {
+ host->chan_tx = NULL;
+ dma_release_channel(chan);
+ }
+ dev_warn(&host->pdev->dev,
+ "DMA failed: %d, falling back to PIO\n", ret);
+ tmio_mmc_enable_dma(host, false);
+ }
+
+ dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d, sg[%d]\n", __func__,
+ desc, cookie, host->sg_len);
+}
+
+static void tmio_mmc_start_dma_tx(struct tmio_mmc_host *host)
+{
+ struct scatterlist *sg = host->sg_ptr, *sg_tmp;
+ struct dma_async_tx_descriptor *desc = NULL;
+ struct dma_chan *chan = host->chan_tx;
+ struct tmio_mmc_data *pdata = host->pdata;
+ dma_cookie_t cookie;
+ int ret, i;
+ bool aligned = true, multiple = true;
+ unsigned int align = (1 << pdata->dma->alignment_shift) - 1;
+
+ for_each_sg(sg, sg_tmp, host->sg_len, i) {
+ if (sg_tmp->offset & align)
+ aligned = false;
+ if (sg_tmp->length & align) {
+ multiple = false;
+ break;
+ }
+ }
+
+ if ((!aligned && (host->sg_len > 1 || sg->length > PAGE_CACHE_SIZE ||
+ (align & PAGE_MASK))) || !multiple) {
+ ret = -EINVAL;
+ goto pio;
+ }
+
+ if (sg->length < TMIO_MMC_MIN_DMA_LEN) {
+ host->force_pio = true;
+ return;
+ }
+
+ tmio_mmc_disable_mmc_irqs(host, TMIO_STAT_TXRQ);
+
+ /* The only sg element can be unaligned, use our bounce buffer then */
+ if (!aligned) {
+ unsigned long flags;
+ void *sg_vaddr = tmio_mmc_kmap_atomic(sg, &flags);
+ sg_init_one(&host->bounce_sg, host->bounce_buf, sg->length);
+ memcpy(host->bounce_buf, sg_vaddr, host->bounce_sg.length);
+ tmio_mmc_kunmap_atomic(sg, &flags, sg_vaddr);
+ host->sg_ptr = &host->bounce_sg;
+ sg = host->sg_ptr;
+ }
+
+ ret = dma_map_sg(chan->device->dev, sg, host->sg_len, DMA_TO_DEVICE);
+ if (ret > 0)
+ desc = chan->device->device_prep_slave_sg(chan, sg, ret,
+ DMA_TO_DEVICE, DMA_CTRL_ACK);
+
+ if (desc) {
+ cookie = dmaengine_submit(desc);
+ if (cookie < 0) {
+ desc = NULL;
+ ret = cookie;
+ }
+ }
+ dev_dbg(&host->pdev->dev, "%s(): mapped %d -> %d, cookie %d, rq %p\n",
+ __func__, host->sg_len, ret, cookie, host->mrq);
+
+pio:
+ if (!desc) {
+ /* DMA failed, fall back to PIO */
+ if (ret >= 0)
+ ret = -EIO;
+ host->chan_tx = NULL;
+ dma_release_channel(chan);
+ /* Free the Rx channel too */
+ chan = host->chan_rx;
+ if (chan) {
+ host->chan_rx = NULL;
+ dma_release_channel(chan);
+ }
+ dev_warn(&host->pdev->dev,
+ "DMA failed: %d, falling back to PIO\n", ret);
+ tmio_mmc_enable_dma(host, false);
+ }
+
+ dev_dbg(&host->pdev->dev, "%s(): desc %p, cookie %d\n", __func__,
+ desc, cookie);
+}
+
+void tmio_mmc_start_dma(struct tmio_mmc_host *host,
+ struct mmc_data *data)
+{
+ if (data->flags & MMC_DATA_READ) {
+ if (host->chan_rx)
+ tmio_mmc_start_dma_rx(host);
+ } else {
+ if (host->chan_tx)
+ tmio_mmc_start_dma_tx(host);
+ }
+}
+
+static void tmio_mmc_issue_tasklet_fn(unsigned long priv)
+{
+ struct tmio_mmc_host *host = (struct tmio_mmc_host *)priv;
+ struct dma_chan *chan = NULL;
+
+ spin_lock_irq(&host->lock);
+
+ if (host && host->data) {
+ if (host->data->flags & MMC_DATA_READ)
+ chan = host->chan_rx;
+ else
+ chan = host->chan_tx;
+ }
+
+ spin_unlock_irq(&host->lock);
+
+ tmio_mmc_enable_mmc_irqs(host, TMIO_STAT_DATAEND);
+
+ if (chan)
+ dma_async_issue_pending(chan);
+}
+
+static void tmio_mmc_tasklet_fn(unsigned long arg)
+{
+ struct tmio_mmc_host *host = (struct tmio_mmc_host *)arg;
+
+ spin_lock_irq(&host->lock);
+
+ if (!host->data)
+ goto out;
+
+ if (host->data->flags & MMC_DATA_READ)
+ dma_unmap_sg(host->chan_rx->device->dev,
+ host->sg_ptr, host->sg_len,
+ DMA_FROM_DEVICE);
+ else
+ dma_unmap_sg(host->chan_tx->device->dev,
+ host->sg_ptr, host->sg_len,
+ DMA_TO_DEVICE);
+
+ tmio_mmc_do_data_irq(host);
+out:
+ spin_unlock_irq(&host->lock);
+}
+
+/* It might be necessary to make filter MFD specific */
+static bool tmio_mmc_filter(struct dma_chan *chan, void *arg)
+{
+ dev_dbg(chan->device->dev, "%s: slave data %p\n", __func__, arg);
+ chan->private = arg;
+ return true;
+}
+
+void tmio_mmc_request_dma(struct tmio_mmc_host *host, struct tmio_mmc_data *pdata)
+{
+ /* We can only either use DMA for both Tx and Rx or not use it at all */
+ if (pdata->dma) {
+ dma_cap_mask_t mask;
+
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+
+ host->chan_tx = dma_request_channel(mask, tmio_mmc_filter,
+ pdata->dma->chan_priv_tx);
+ dev_dbg(&host->pdev->dev, "%s: TX: got channel %p\n", __func__,
+ host->chan_tx);
+
+ if (!host->chan_tx)
+ return;
+
+ host->chan_rx = dma_request_channel(mask, tmio_mmc_filter,
+ pdata->dma->chan_priv_rx);
+ dev_dbg(&host->pdev->dev, "%s: RX: got channel %p\n", __func__,
+ host->chan_rx);
+
+ if (!host->chan_rx)
+ goto ereqrx;
+
+ host->bounce_buf = (u8 *)__get_free_page(GFP_KERNEL | GFP_DMA);
+ if (!host->bounce_buf)
+ goto ebouncebuf;
+
+ tasklet_init(&host->dma_complete, tmio_mmc_tasklet_fn, (unsigned long)host);
+ tasklet_init(&host->dma_issue, tmio_mmc_issue_tasklet_fn, (unsigned long)host);
+
+ tmio_mmc_enable_dma(host, true);
+
+ return;
+ebouncebuf:
+ dma_release_channel(host->chan_rx);
+ host->chan_rx = NULL;
+ereqrx:
+ dma_release_channel(host->chan_tx);
+ host->chan_tx = NULL;
+ return;
+ }
+}
+
+void tmio_mmc_release_dma(struct tmio_mmc_host *host)
+{
+ if (host->chan_tx) {
+ struct dma_chan *chan = host->chan_tx;
+ host->chan_tx = NULL;
+ dma_release_channel(chan);
+ }
+ if (host->chan_rx) {
+ struct dma_chan *chan = host->chan_rx;
+ host->chan_rx = NULL;
+ dma_release_channel(chan);
+ }
+ if (host->bounce_buf) {
+ free_pages((unsigned long)host->bounce_buf, 0);
+ host->bounce_buf = NULL;
+ }
+}
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-12 03:10:21 +0000