On Tue, Apr 28, 2015 at 11:03:23AM +0200, Maxime Ripard wrote:
> The XDMAC supports interleaved tranfers through its flexible descriptor
> configuration.
>
> Add support for that kind of transfers to the dmaengine driver.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/dma/at_xdmac.c | 219 +++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 219 insertions(+)
>
> diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
> index 67e566b2b24f..3c40c5ef043d 100644
> --- a/drivers/dma/at_xdmac.c
> +++ b/drivers/dma/at_xdmac.c
> @@ -485,6 +485,19 @@ static void at_xdmac_queue_desc(struct dma_chan *chan,
> __func__, prev, prev->lld.mbr_nda);
> }
>
> +static inline void at_xdmac_increment_block_count(struct dma_chan *chan,
> + struct at_xdmac_desc *desc)
> +{
> + if (!desc)
> + return;
> +
> + desc->lld.mbr_bc++;
> +
> + dev_dbg(chan2dev(chan),
> + "%s: incrementing the block count of the desc 0x%p\n",
> + __func__, desc);
> +}
> +
> static struct dma_chan *at_xdmac_xlate(struct of_phandle_args *dma_spec,
> struct of_dma *of_dma)
> {
> @@ -782,6 +795,210 @@ static inline u32 at_xdmac_align_width(struct dma_chan *chan, dma_addr_t addr)
> return width;
> }
>
> +static struct at_xdmac_desc *
> +at_xdmac_interleaved_queue_desc(struct dma_chan *chan,
> + struct at_xdmac_chan *atchan,
> + struct at_xdmac_desc *prev,
> + dma_addr_t src, dma_addr_t dst,
> + struct dma_interleaved_template *xt,
> + struct data_chunk *chunk)
> +{
> + struct at_xdmac_desc *desc = NULL;
this seems superflous
> + u32 dwidth;
> + unsigned long flags;
> + size_t ublen;
> + /*
> + * WARNING: The channel configuration is set here since there is no
> + * dmaengine_slave_config call in this case. Moreover we don't know the
> + * direction, it involves we can't dynamically set the source and dest
> + * interface so we have to use the same one. Only interface 0 allows EBI
> + * access. Hopefully we can access DDR through both ports (at least on
> + * SAMA5D4x), so we can use the same interface for source and dest,
> + * that solves the fact we don't know the direction.
> + */
> + u32 chan_cc = AT_XDMAC_CC_DIF(0)
> + | AT_XDMAC_CC_SIF(0)
> + | AT_XDMAC_CC_MBSIZE_SIXTEEN
> + | AT_XDMAC_CC_TYPE_MEM_TRAN;
> +
> + dwidth = at_xdmac_align_width(chan, src | dst | chunk->size);
> + if (chunk->size >= (AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth)) {
> + dev_dbg(chan2dev(chan),
> + "%s: chunk too big (%d, max size %lu)...\n",
> + __func__, chunk->size,
> + AT_XDMAC_MBR_UBC_UBLEN_MAX << dwidth);
> + return NULL;
> + }
> +
> + if (prev)
> + dev_dbg(chan2dev(chan),
> + "Adding items at the end of desc 0x%p\n", prev);
> +
> + if (xt->src_inc) {
> + if (xt->src_sgl)
> + chan_cc |= AT_XDMAC_CC_SAM_UBS_DS_AM;
> + else
> + chan_cc |= AT_XDMAC_CC_SAM_INCREMENTED_AM;
> + }
> +
> + if (xt->dst_inc) {
> + if (xt->dst_sgl)
> + chan_cc |= AT_XDMAC_CC_DAM_UBS_DS_AM;
> + else
> + chan_cc |= AT_XDMAC_CC_DAM_INCREMENTED_AM;
> + }
> +
> + spin_lock_irqsave(&atchan->lock, flags);
> + desc = at_xdmac_get_desc(atchan);
> + spin_unlock_irqrestore(&atchan->lock, flags);
> + if (!desc) {
> + dev_err(chan2dev(chan), "can't get descriptor\n");
> + return NULL;
> + }
> +
> + chan_cc |= AT_XDMAC_CC_DWIDTH(dwidth);
> +
> + ublen = chunk->size >> dwidth;
> +
> + desc->lld.mbr_sa = src;
> + desc->lld.mbr_da = dst;
> +
> + if (xt->src_inc && xt->src_sgl) {
> + if (chunk->src_icg)
> + desc->lld.mbr_sus = chunk->src_icg;
> + else
> + desc->lld.mbr_sus = chunk->icg;
> + }
> +
> + if (xt->dst_inc && xt->dst_sgl) {
> + if (chunk->dst_icg)
> + desc->lld.mbr_dus = chunk->dst_icg;
> + else
> + desc->lld.mbr_dus = chunk->icg;
> + }
> +
> + desc->lld.mbr_ubc = AT_XDMAC_MBR_UBC_NDV3
> + | AT_XDMAC_MBR_UBC_NDEN
> + | AT_XDMAC_MBR_UBC_NSEN
> + | ublen;
> + desc->lld.mbr_cfg = chan_cc;
> +
> + dev_dbg(chan2dev(chan),
> + "%s: lld: mbr_sa=0x%08x, mbr_da=0x%08x, mbr_ubc=0x%08x, mbr_cfg=0x%08x\n",
> + __func__, desc->lld.mbr_sa, desc->lld.mbr_da,
> + desc->lld.mbr_ubc, desc->lld.mbr_cfg);
> +
> + /* Chain lld. */
> + if (prev)
> + at_xdmac_queue_desc(chan, prev, desc);
otherwise you don't queue... what did i miss?
> +
> + return desc;
> +}
> +
> +static struct dma_async_tx_descriptor *
> +at_xdmac_prep_interleaved(struct dma_chan *chan,
> + struct dma_interleaved_template *xt,
> + unsigned long flags)
> +{
> + struct at_xdmac_chan *atchan = to_at_xdmac_chan(chan);
> + struct at_xdmac_desc *prev = NULL, *first = NULL;
> + struct data_chunk *chunk, *prev_chunk = NULL;
> + dma_addr_t dst_addr, src_addr;
> + size_t prev_src_skip = 0, src_skip = 0, len = 0;
> + size_t prev_dst_skip = 0, dst_skip = 0;
dont see why src_skip and dst_skip should be set?
> + size_t prev_dst_icg = 0, prev_src_icg = 0;
> + int i;
> +
> + if (!xt || (xt->numf != 1) || (xt->dir != DMA_MEM_TO_MEM))
> + return NULL;
> +
> + dev_dbg(chan2dev(chan), "%s: src=0x%08x, dest=0x%08x, numf=%d, frame_size=%d, flags=0x%lx\n",
> + __func__, xt->src_start, xt->dst_start, xt->numf,
> + xt->frame_size, flags);
> +
> + src_addr = xt->src_start;
> + dst_addr = xt->dst_start;
> +
> + for (i = 0; i < xt->frame_size; i++) {
> + struct at_xdmac_desc *desc;
> + size_t src_icg = 0, dst_icg = 0;
> +
> + chunk = xt->sgl + i;
> +
> + if (xt->dst_inc) {
> + if (chunk->dst_icg)
> + dst_icg = chunk->dst_icg;
> + else if (xt->dst_sgl)
> + dst_icg = chunk->icg;
> + }
> +
> + if (xt->src_inc) {
> + if (chunk->src_icg)
> + src_icg = chunk->src_icg;
> + else if (xt->src_sgl)
> + src_icg = chunk->icg;
> + }
perhpas a common warpper for this logic?
> +
> + src_skip = chunk->size + src_icg;
> + dst_skip = chunk->size + dst_icg;
> +
> + dev_dbg(chan2dev(chan),
> + "%s: chunk size=%d, src icg=%d, dst icg=%d\n",
> + __func__, chunk->size, src_icg, dst_icg);
> +
> + /*
> + * Handle the case where we just have the same
> + * transfer to setup, we can just increase the
> + * block number and reuse the same descriptor.
> + */
> + if (prev_chunk && prev &&
> + (prev_chunk->size == chunk->size) &&
> + (prev_src_icg == src_icg) &&
> + (prev_dst_icg == dst_icg)) {
the variables prev_src_icg and prev_dst_icg are initailzed to zero but never
updated, seems to have missing stuff
> + dev_dbg(chan2dev(chan),
> + "%s: same configuration that the previous chunk, merging the descriptors...\n",
> + __func__);
> + at_xdmac_increment_block_count(chan, prev);
> + continue;
> + }
> +
> + desc = at_xdmac_interleaved_queue_desc(chan, atchan,
> + prev,
> + src_addr, dst_addr,
> + xt, chunk);
> + if (!desc) {
> + list_splice_init(&first->descs_list,
> + &atchan->free_descs_list);
> + return NULL;
> + }
> +
> + if (!first)
> + first = desc;
> +
> + dev_dbg(chan2dev(chan), "%s: add desc 0x%p to descs_list 0x%p\n",
> + __func__, desc, first);
> + list_add_tail(&desc->desc_node, &first->descs_list);
> +
> + if (xt->src_sgl)
> + src_addr += src_skip;
> +
> + if (xt->dst_sgl)
> + dst_addr += dst_skip;
> +
> + len += chunk->size;
> + prev_chunk = chunk;
> + prev_dst_skip = dst_skip;
> + prev_src_skip = src_skip;
these two values are not used anywhere so why keep track of it?
> + prev = desc;
> + }
> +
> + first->tx_dma_desc.cookie = -EBUSY;
> + first->tx_dma_desc.flags = flags;
> + first->xfer_size = len;
> +
> + return &first->tx_dma_desc;
> +}
Thanks
--
~Vinod
> +
> static struct dma_async_tx_descriptor *
> at_xdmac_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
> size_t len, unsigned long flags)
> @@ -1404,6 +1621,7 @@ static int at_xdmac_probe(struct platform_device *pdev)
> }
>
> dma_cap_set(DMA_CYCLIC, atxdmac->dma.cap_mask);
> + dma_cap_set(DMA_INTERLEAVE, atxdmac->dma.cap_mask);
> dma_cap_set(DMA_MEMCPY, atxdmac->dma.cap_mask);
> dma_cap_set(DMA_SLAVE, atxdmac->dma.cap_mask);
> /*
> @@ -1417,6 +1635,7 @@ static int at_xdmac_probe(struct platform_device *pdev)
> atxdmac->dma.device_tx_status = at_xdmac_tx_status;
> atxdmac->dma.device_issue_pending = at_xdmac_issue_pending;
> atxdmac->dma.device_prep_dma_cyclic = at_xdmac_prep_dma_cyclic;
> + atxdmac->dma.device_prep_interleaved_dma = at_xdmac_prep_interleaved;
> atxdmac->dma.device_prep_dma_memcpy = at_xdmac_prep_dma_memcpy;
> atxdmac->dma.device_prep_slave_sg = at_xdmac_prep_slave_sg;
> atxdmac->dma.device_config = at_xdmac_device_config;
> --
> 2.3.6
>
--
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