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rapidio: add DMA engine support for RIO data transfers

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Adds DMA Engine framework support into RapidIO subsystem.

Uses DMA Engine DMA_SLAVE interface to generate data transfers to/from
remote RapidIO target devices.

Introduces RapidIO-specific wrapper for prep_slave_sg() interface with an
extra parameter to pass target specific information.

Uses scatterlist to describe local data buffer.  Address flat data buffer
on a remote side.

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Acked-by: Vinod Koul <vinod.koul@linux.intel.com>
Cc: Li Yang <leoli@freescale.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alexandre Bounine
2012-05-31 16:26:38 -07:00
committed by Linus Torvalds
parent ce2d52cc13
commit e42d98ebe7
5 changed files with 163 additions and 0 deletions
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81
drivers/rapidio/rio.c
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@@ -1121,6 +1121,87 @@ int rio_std_route_clr_table(struct rio_mport *mport, u16 destid, u8 hopcount,
return 0;
}
#ifdef CONFIG_RAPIDIO_DMA_ENGINE
static bool rio_chan_filter(struct dma_chan *chan, void *arg)
{
struct rio_dev *rdev = arg;
/* Check that DMA device belongs to the right MPORT */
return (rdev->net->hport ==
container_of(chan->device, struct rio_mport, dma));
}
/**
* rio_request_dma - request RapidIO capable DMA channel that supports
* specified target RapidIO device.
* @rdev: RIO device control structure
*
* Returns pointer to allocated DMA channel or NULL if failed.
*/
struct dma_chan *rio_request_dma(struct rio_dev *rdev)
{
dma_cap_mask_t mask;
struct dma_chan *dchan;
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
dchan = dma_request_channel(mask, rio_chan_filter, rdev);
return dchan;
}
EXPORT_SYMBOL_GPL(rio_request_dma);
/**
* rio_release_dma - release specified DMA channel
* @dchan: DMA channel to release
*/
void rio_release_dma(struct dma_chan *dchan)
{
dma_release_channel(dchan);
}
EXPORT_SYMBOL_GPL(rio_release_dma);
/**
* rio_dma_prep_slave_sg - RapidIO specific wrapper
* for device_prep_slave_sg callback defined by DMAENGINE.
* @rdev: RIO device control structure
* @dchan: DMA channel to configure
* @data: RIO specific data descriptor
* @direction: DMA data transfer direction (TO or FROM the device)
* @flags: dmaengine defined flags
*
* Initializes RapidIO capable DMA channel for the specified data transfer.
* Uses DMA channel private extension to pass information related to remote
* target RIO device.
* Returns pointer to DMA transaction descriptor or NULL if failed.
*/
struct dma_async_tx_descriptor *rio_dma_prep_slave_sg(struct rio_dev *rdev,
struct dma_chan *dchan, struct rio_dma_data *data,
enum dma_transfer_direction direction, unsigned long flags)
{
struct dma_async_tx_descriptor *txd = NULL;
struct rio_dma_ext rio_ext;
if (dchan->device->device_prep_slave_sg == NULL) {
pr_err("%s: prep_rio_sg == NULL\n", __func__);
return NULL;
}
rio_ext.destid = rdev->destid;
rio_ext.rio_addr_u = data->rio_addr_u;
rio_ext.rio_addr = data->rio_addr;
rio_ext.wr_type = data->wr_type;
txd = dmaengine_prep_rio_sg(dchan, data->sg, data->sg_len,
direction, flags, &rio_ext);
return txd;
}
EXPORT_SYMBOL_GPL(rio_dma_prep_slave_sg);
#endif /* CONFIG_RAPIDIO_DMA_ENGINE */
static void rio_fixup_device(struct rio_dev *dev)
{
}