diff options
| -rw-r--r-- | Documentation/dmaengine.txt | 8 | ||||
| -rw-r--r-- | drivers/dma/dmaengine.c | 4 | ||||
| -rw-r--r-- | include/linux/dmaengine.h | 78 |
3 files changed, 85 insertions, 5 deletions
diff --git a/Documentation/dmaengine.txt b/Documentation/dmaengine.txt index 94b7e0f96b38..bbe6cb3d1856 100644 --- a/Documentation/dmaengine.txt +++ b/Documentation/dmaengine.txt @@ -75,6 +75,10 @@ The slave DMA usage consists of following steps: slave_sg - DMA a list of scatter gather buffers from/to a peripheral dma_cyclic - Perform a cyclic DMA operation from/to a peripheral till the operation is explicitly stopped. + interleaved_dma - This is common to Slave as well as M2M clients. For slave + address of devices' fifo could be already known to the driver. + Various types of operations could be expressed by setting + appropriate values to the 'dma_interleaved_template' members. A non-NULL return of this transfer API represents a "descriptor" for the given transaction. @@ -89,6 +93,10 @@ The slave DMA usage consists of following steps: struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len, size_t period_len, enum dma_data_direction direction); + struct dma_async_tx_descriptor *(*device_prep_interleaved_dma)( + struct dma_chan *chan, struct dma_interleaved_template *xt, + unsigned long flags); + The peripheral driver is expected to have mapped the scatterlist for the DMA operation prior to calling device_prep_slave_sg, and must keep the scatterlist mapped until the DMA operation has completed. diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index b48967b499da..a6c6051ec858 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -693,12 +693,12 @@ int dma_async_device_register(struct dma_device *device) !device->device_prep_dma_interrupt); BUG_ON(dma_has_cap(DMA_SG, device->cap_mask) && !device->device_prep_dma_sg); - BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) && - !device->device_prep_slave_sg); BUG_ON(dma_has_cap(DMA_CYCLIC, device->cap_mask) && !device->device_prep_dma_cyclic); BUG_ON(dma_has_cap(DMA_SLAVE, device->cap_mask) && !device->device_control); + BUG_ON(dma_has_cap(DMA_INTERLEAVE, device->cap_mask) && + !device->device_prep_interleaved_dma); BUG_ON(!device->device_alloc_chan_resources); BUG_ON(!device->device_free_chan_resources); diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index a865b3a354cd..5532bb8b500c 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -71,10 +71,10 @@ enum dma_transaction_type { DMA_ASYNC_TX, DMA_SLAVE, DMA_CYCLIC, -}; - + DMA_INTERLEAVE, /* last transaction type for creation of the capabilities mask */ -#define DMA_TX_TYPE_END (DMA_CYCLIC + 1) + DMA_TX_TYPE_END, +}; /** * enum dma_transfer_direction - dma transfer mode and direction indicator @@ -91,6 +91,74 @@ enum dma_transfer_direction { }; /** + * Interleaved Transfer Request + * ---------------------------- + * A chunk is collection of contiguous bytes to be transfered. + * The gap(in bytes) between two chunks is called inter-chunk-gap(ICG). + * ICGs may or maynot change between chunks. + * A FRAME is the smallest series of contiguous {chunk,icg} pairs, + * that when repeated an integral number of times, specifies the transfer. + * A transfer template is specification of a Frame, the number of times + * it is to be repeated and other per-transfer attributes. + * + * Practically, a client driver would have ready a template for each + * type of transfer it is going to need during its lifetime and + * set only 'src_start' and 'dst_start' before submitting the requests. + * + * + * | Frame-1 | Frame-2 | ~ | Frame-'numf' | + * |====....==.===...=...|====....==.===...=...| ~ |====....==.===...=...| + * + * == Chunk size + * ... ICG + */ + +/** + * struct data_chunk - Element of scatter-gather list that makes a frame. + * @size: Number of bytes to read from source. + * size_dst := fn(op, size_src), so doesn't mean much for destination. + * @icg: Number of bytes to jump after last src/dst address of this + * chunk and before first src/dst address for next chunk. + * Ignored for dst(assumed 0), if dst_inc is true and dst_sgl is false. + * Ignored for src(assumed 0), if src_inc is true and src_sgl is false. + */ +struct data_chunk { + size_t size; + size_t icg; +}; + +/** + * struct dma_interleaved_template - Template to convey DMAC the transfer pattern + * and attributes. + * @src_start: Bus address of source for the first chunk. + * @dst_start: Bus address of destination for the first chunk. + * @dir: Specifies the type of Source and Destination. + * @src_inc: If the source address increments after reading from it. + * @dst_inc: If the destination address increments after writing to it. + * @src_sgl: If the 'icg' of sgl[] applies to Source (scattered read). + * Otherwise, source is read contiguously (icg ignored). + * Ignored if src_inc is false. + * @dst_sgl: If the 'icg' of sgl[] applies to Destination (scattered write). + * Otherwise, destination is filled contiguously (icg ignored). + * Ignored if dst_inc is false. + * @numf: Number of frames in this template. + * @frame_size: Number of chunks in a frame i.e, size of sgl[]. + * @sgl: Array of {chunk,icg} pairs that make up a frame. + */ +struct dma_interleaved_template { + dma_addr_t src_start; + dma_addr_t dst_start; + enum dma_transfer_direction dir; + bool src_inc; + bool dst_inc; + bool src_sgl; + bool dst_sgl; + size_t numf; + size_t frame_size; + struct data_chunk sgl[0]; +}; + +/** * enum dma_ctrl_flags - DMA flags to augment operation preparation, * control completion, and communicate status. * @DMA_PREP_INTERRUPT - trigger an interrupt (callback) upon completion of @@ -445,6 +513,7 @@ struct dma_tx_state { * @device_prep_dma_cyclic: prepare a cyclic dma operation suitable for audio. * The function takes a buffer of size buf_len. The callback function will * be called after period_len bytes have been transferred. + * @device_prep_interleaved_dma: Transfer expression in a generic way. * @device_control: manipulate all pending operations on a channel, returns * zero or error code * @device_tx_status: poll for transaction completion, the optional @@ -509,6 +578,9 @@ struct dma_device { struct dma_async_tx_descriptor *(*device_prep_dma_cyclic)( struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len, size_t period_len, enum dma_transfer_direction direction); + struct dma_async_tx_descriptor *(*device_prep_interleaved_dma)( + struct dma_chan *chan, struct dma_interleaved_template *xt, + unsigned long flags); int (*device_control)(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned long arg); |