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dma: mmp_pdma: add support for cyclic DMA descriptors

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Provide a callback to prepare cyclic DMA transfers.
This is for instance needed for audio channel transport.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Daniel Mack 2013-08-21 14:08:56 +02:00 committed by Vinod Koul
parent 0cd6156177
commit 50440d74aa
1 changed files with 111 additions and 1 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

112
drivers/dma/mmp_pdma.c
View file

@ -98,6 +98,9 @@ struct mmp_pdma_chan {
struct mmp_pdma_phy *phy;
enum dma_transfer_direction dir;
struct mmp_pdma_desc_sw *cyclic_first; /* first desc_sw if channel
* is in cyclic mode */
/* channel's basic info */
struct tasklet_struct tasklet;
u32 dcmd;
@ -500,6 +503,8 @@ mmp_pdma_prep_memcpy(struct dma_chan *dchan,
new->desc.ddadr = DDADR_STOP;
new->desc.dcmd |= DCMD_ENDIRQEN;
chan->cyclic_first = NULL;
return &first->async_tx;
fail:
@ -575,6 +580,94 @@ mmp_pdma_prep_slave_sg(struct dma_chan *dchan, struct scatterlist *sgl,
new->desc.ddadr = DDADR_STOP;
new->desc.dcmd |= DCMD_ENDIRQEN;
chan->dir = dir;
chan->cyclic_first = NULL;
return &first->async_tx;
fail:
if (first)
mmp_pdma_free_desc_list(chan, &first->tx_list);
return NULL;
}
static struct dma_async_tx_descriptor *mmp_pdma_prep_dma_cyclic(
struct dma_chan *dchan, dma_addr_t buf_addr, size_t len,
size_t period_len, enum dma_transfer_direction direction,
unsigned long flags, void *context)
{
struct mmp_pdma_chan *chan;
struct mmp_pdma_desc_sw *first = NULL, *prev = NULL, *new;
dma_addr_t dma_src, dma_dst;
if (!dchan || !len || !period_len)
return NULL;
/* the buffer length must be a multiple of period_len */
if (len % period_len != 0)
return NULL;
if (period_len > PDMA_MAX_DESC_BYTES)
return NULL;
chan = to_mmp_pdma_chan(dchan);
switch (direction) {
case DMA_MEM_TO_DEV:
dma_src = buf_addr;
dma_dst = chan->dev_addr;
break;
case DMA_DEV_TO_MEM:
dma_dst = buf_addr;
dma_src = chan->dev_addr;
break;
default:
dev_err(chan->dev, "Unsupported direction for cyclic DMA\n");
return NULL;
}
chan->dir = direction;
do {
/* Allocate the link descriptor from DMA pool */
new = mmp_pdma_alloc_descriptor(chan);
if (!new) {
dev_err(chan->dev, "no memory for desc\n");
goto fail;
}
new->desc.dcmd = chan->dcmd | DCMD_ENDIRQEN |
(DCMD_LENGTH & period_len);
new->desc.dsadr = dma_src;
new->desc.dtadr = dma_dst;
if (!first)
first = new;
else
prev->desc.ddadr = new->async_tx.phys;
new->async_tx.cookie = 0;
async_tx_ack(&new->async_tx);
prev = new;
len -= period_len;
if (chan->dir == DMA_MEM_TO_DEV)
dma_src += period_len;
else
dma_dst += period_len;
/* Insert the link descriptor to the LD ring */
list_add_tail(&new->node, &first->tx_list);
} while (len);
first->async_tx.flags = flags; /* client is in control of this ack */
first->async_tx.cookie = -EBUSY;
/* make the cyclic link */
new->desc.ddadr = first->async_tx.phys;
chan->cyclic_first = first;
return &first->async_tx;
fail:
@ -681,8 +774,23 @@ static void dma_do_tasklet(unsigned long data)
LIST_HEAD(chain_cleanup);
unsigned long flags;
/* submit pending list; callback for each desc; free desc */
if (chan->cyclic_first) {
dma_async_tx_callback cb = NULL;
void *cb_data = NULL;
spin_lock_irqsave(&chan->desc_lock, flags);
desc = chan->cyclic_first;
cb = desc->async_tx.callback;
cb_data = desc->async_tx.callback_param;
spin_unlock_irqrestore(&chan->desc_lock, flags);
if (cb)
cb(cb_data);
return;
}
/* submit pending list; callback for each desc; free desc */
spin_lock_irqsave(&chan->desc_lock, flags);
list_for_each_entry_safe(desc, _desc, &chan->chain_running, node) {
@ -876,12 +984,14 @@ static int mmp_pdma_probe(struct platform_device *op)
dma_cap_set(DMA_SLAVE, pdev->device.cap_mask);
dma_cap_set(DMA_MEMCPY, pdev->device.cap_mask);
dma_cap_set(DMA_CYCLIC, pdev->device.cap_mask);
pdev->device.dev = &op->dev;
pdev->device.device_alloc_chan_resources = mmp_pdma_alloc_chan_resources;
pdev->device.device_free_chan_resources = mmp_pdma_free_chan_resources;
pdev->device.device_tx_status = mmp_pdma_tx_status;
pdev->device.device_prep_dma_memcpy = mmp_pdma_prep_memcpy;
pdev->device.device_prep_slave_sg = mmp_pdma_prep_slave_sg;
pdev->device.device_prep_dma_cyclic = mmp_pdma_prep_dma_cyclic;
pdev->device.device_issue_pending = mmp_pdma_issue_pending;
pdev->device.device_control = mmp_pdma_control;
pdev->device.copy_align = PDMA_ALIGNMENT;