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dmaengine: at_hdmac: Add support for memory to memory sg transfers 

This patch adds support for memory to memory scatter-gather transfers.

Changes from V1:
   * Fixed coding style of the multi-line comments.

Changes from V2:
   * Added setup of 'desc->tx_width' that is needed to calculate the
     residue.

Signed-off-by: Torsten Fleischer <torfl6749@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Torsten Fleischer 2015-02-23 17:54:11 +01:00 committed by Vinod Koul
parent 26f7af37ee
commit 265567fbca
1 changed files with 164 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

175
drivers/dma/at_hdmac.c
View File

@ -65,6 +65,21 @@ static void atc_issue_pending(struct dma_chan *chan);
/*----------------------------------------------------------------------*/
static inline unsigned int atc_get_xfer_width(dma_addr_t src, dma_addr_t dst,
size_t len)
{
unsigned int width;
if (!((src | dst | len) & 3))
width = 2;
else if (!((src | dst | len) & 1))
width = 1;
else
width = 0;
return width;
}
static struct at_desc *atc_first_active(struct at_dma_chan *atchan)
{
return list_first_entry(&atchan->active_list,
@ -628,16 +643,10 @@ atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
* We can be a lot more clever here, but this should take care
* of the most common optimization.
*/
if (!((src | dest | len) & 3)) {
ctrla = ATC_SRC_WIDTH_WORD | ATC_DST_WIDTH_WORD;
src_width = dst_width = 2;
} else if (!((src | dest | len) & 1)) {
ctrla = ATC_SRC_WIDTH_HALFWORD | ATC_DST_WIDTH_HALFWORD;
src_width = dst_width = 1;
} else {
ctrla = ATC_SRC_WIDTH_BYTE | ATC_DST_WIDTH_BYTE;
src_width = dst_width = 0;
}
src_width = dst_width = atc_get_xfer_width(src, dest, len);
ctrla = ATC_SRC_WIDTH(src_width) |
ATC_DST_WIDTH(dst_width);
for (offset = 0; offset < len; offset += xfer_count << src_width) {
xfer_count = min_t(size_t, (len - offset) >> src_width,
@ -821,6 +830,144 @@ err:
return NULL;
}
/**
* atc_prep_dma_sg - prepare memory to memory scather-gather operation
* @chan: the channel to prepare operation on
* @dst_sg: destination scatterlist
* @dst_nents: number of destination scatterlist entries
* @src_sg: source scatterlist
* @src_nents: number of source scatterlist entries
* @flags: tx descriptor status flags
*/
static struct dma_async_tx_descriptor *
atc_prep_dma_sg(struct dma_chan *chan,
struct scatterlist *dst_sg, unsigned int dst_nents,
struct scatterlist *src_sg, unsigned int src_nents,
unsigned long flags)
{
struct at_dma_chan *atchan = to_at_dma_chan(chan);
struct at_desc *desc = NULL;
struct at_desc *first = NULL;
struct at_desc *prev = NULL;
unsigned int src_width;
unsigned int dst_width;
size_t xfer_count;
u32 ctrla;
u32 ctrlb;
size_t dst_len = 0, src_len = 0;
dma_addr_t dst = 0, src = 0;
size_t len = 0, total_len = 0;
if (unlikely(dst_nents == 0 || src_nents == 0))
return NULL;
if (unlikely(dst_sg == NULL || src_sg == NULL))
return NULL;
ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN
| ATC_SRC_ADDR_MODE_INCR
| ATC_DST_ADDR_MODE_INCR
| ATC_FC_MEM2MEM;
/*
* loop until there is either no more source or no more destination
* scatterlist entry
*/
while (true) {
/* prepare the next transfer */
if (dst_len == 0) {
/* no more destination scatterlist entries */
if (!dst_sg || !dst_nents)
break;
dst = sg_dma_address(dst_sg);
dst_len = sg_dma_len(dst_sg);
dst_sg = sg_next(dst_sg);
dst_nents--;
}
if (src_len == 0) {
/* no more source scatterlist entries */
if (!src_sg || !src_nents)
break;
src = sg_dma_address(src_sg);
src_len = sg_dma_len(src_sg);
src_sg = sg_next(src_sg);
src_nents--;
}
len = min_t(size_t, src_len, dst_len);
if (len == 0)
continue;
/* take care for the alignment */
src_width = dst_width = atc_get_xfer_width(src, dst, len);
ctrla = ATC_SRC_WIDTH(src_width) |
ATC_DST_WIDTH(dst_width);
/*
* The number of transfers to set up refer to the source width
* that depends on the alignment.
*/
xfer_count = len >> src_width;
if (xfer_count > ATC_BTSIZE_MAX) {
xfer_count = ATC_BTSIZE_MAX;
len = ATC_BTSIZE_MAX << src_width;
}
/* create the transfer */
desc = atc_desc_get(atchan);
if (!desc)
goto err_desc_get;
desc->lli.saddr = src;
desc->lli.daddr = dst;
desc->lli.ctrla = ctrla | xfer_count;
desc->lli.ctrlb = ctrlb;
desc->txd.cookie = 0;
desc->len = len;
/*
* Although we only need the transfer width for the first and
* the last descriptor, its easier to set it to all descriptors.
*/
desc->tx_width = src_width;
atc_desc_chain(&first, &prev, desc);
/* update the lengths and addresses for the next loop cycle */
dst_len -= len;
src_len -= len;
dst += len;
src += len;
total_len += len;
}
/* First descriptor of the chain embedds additional information */
first->txd.cookie = -EBUSY;
first->total_len = total_len;
/* set end-of-link to the last link descriptor of list*/
set_desc_eol(desc);
first->txd.flags = flags; /* client is in control of this ack */
return &first->txd;
err_desc_get:
atc_desc_put(atchan, first);
return NULL;
}
/**
* atc_dma_cyclic_check_values
* Check for too big/unaligned periods and unaligned DMA buffer
@ -1421,8 +1568,10 @@ static int __init at_dma_probe(struct platform_device *pdev)
/* setup platform data for each SoC */
dma_cap_set(DMA_MEMCPY, at91sam9rl_config.cap_mask);
dma_cap_set(DMA_SG, at91sam9rl_config.cap_mask);
dma_cap_set(DMA_MEMCPY, at91sam9g45_config.cap_mask);
dma_cap_set(DMA_SLAVE, at91sam9g45_config.cap_mask);
dma_cap_set(DMA_SG, at91sam9g45_config.cap_mask);
/* get DMA parameters from controller type */
plat_dat = at_dma_get_driver_data(pdev);
@ -1542,11 +1691,15 @@ static int __init at_dma_probe(struct platform_device *pdev)
atdma->dma_common.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
}
if (dma_has_cap(DMA_SG, atdma->dma_common.cap_mask))
atdma->dma_common.device_prep_dma_sg = atc_prep_dma_sg;
dma_writel(atdma, EN, AT_DMA_ENABLE);
dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s), %d channels\n",
dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s%s), %d channels\n",
dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask) ? "cpy " : "",
dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask) ? "slave " : "",
dma_has_cap(DMA_SG, atdma->dma_common.cap_mask) ? "sg-cpy " : "",
plat_dat->nr_channels);
dma_async_device_register(&atdma->dma_common);