[PATCH v1 1/4] dmaengine: imx-sdma: add memcpy interface

Robin Gong
2018-07-11T05:34:19Z

> Hi Robin,
>
> On 11-07-18, 00:23, Robin Gong wrote:
> > Add MEMCPY support, meanwhile, add SDMA_BD_MAX_CNT instead of
> > '0xffff'.
>
> latter part should be its own patch. Never mix things
Okay, I will split it even for this minor change.
>
> > +static struct dma_async_tx_descriptor *sdma_prep_memcpy(
> > + struct dma_chan *chan, dma_addr_t dma_dst,
> > + dma_addr_t dma_src, size_t len, unsigned long flags) {
> > + struct sdma_channel *sdmac = to_sdma_chan(chan);
> > + struct sdma_engine *sdma = sdmac->sdma;
> > + int channel = sdmac->channel;
> > + size_t count;
> > + int i = 0, param;
> > + struct sdma_buffer_descriptor *bd;
> > + struct sdma_desc *desc;
> > +
> > + if (!chan || !len)
> > + return NULL;
> > +
> > + dev_dbg(sdma->dev, "memcpy: %pad->%pad, len=%zu, channel=%d.\n",
> > + &dma_src, &dma_dst, len, channel);
> > +
> > + desc = sdma_transfer_init(sdmac, DMA_MEM_TO_MEM, len /
> SDMA_BD_MAX_CNT
> > + + 1);
>
> this looks quite odd to read consider:
>
> esc = sdma_transfer_init(sdmac, DMA_MEM_TO_MEM,
> len / SDMA_BD_MAX_CNT + 1);
>
Okay, will fix on v2.
> > + if (!desc)
> > + goto err_out;
> > +
> > + do {
> > + count = min_t(size_t, len, SDMA_BD_MAX_CNT);
> > + bd = &desc->bd[i];
> > + bd->buffer_addr = dma_src;
> > + bd->ext_buffer_addr = dma_dst;
> > + bd->mode.count = count;
> > + desc->chn_count += count;
> > +
> > + switch (sdmac->word_size) {
> > + case DMA_SLAVE_BUSWIDTH_4_BYTES:
>
> This looks wrong, we are in memcpy, there is no SLAVE so no SLAVE widths..
>
Okay, will remove check bus width.
> > static struct dma_async_tx_descriptor *sdma_prep_slave_sg(
> > struct dma_chan *chan, struct scatterlist *sgl,
> > unsigned int sg_len, enum dma_transfer_direction direction, @@
> > -1344,9 +1431,9 @@ static struct dma_async_tx_descriptor
> > *sdma_prep_slave_sg(
> >
> > count = sg_dma_len(sg);
> >
> > - if (count > 0xffff) {
> > + if (count > SDMA_BD_MAX_CNT) {
> > dev_err(sdma->dev, "SDMA channel %d: maximum bytes for sg
> entry exceeded: %d > %d\n",
> > - channel, count, 0xffff);
> > + channel, count, SDMA_BD_MAX_CNT);
>
> these changes dont belong to this patch
Will split in v2.
>
> > @@ -1486,6 +1573,8 @@ static int sdma_config(struct dma_chan *chan,
> > sdmac->watermark_level |= (dmaengine_cfg->dst_maxburst << 16)
> &
> > SDMA_WATERMARK_LEVEL_HWML;
> > sdmac->word_size = dmaengine_cfg->dst_addr_width;
> > + } else if (dmaengine_cfg->direction == DMA_MEM_TO_MEM) {
> > + sdmac->word_size = dmaengine_cfg->dst_addr_width;
>
> same here too, we are in .device_config which deals with slave. Not memcpy!
Will remove it.
>
> > } else {
> > sdmac->per_address = dmaengine_cfg->dst_addr;
> > sdmac->watermark_level = dmaengine_cfg->dst_maxburst * @@
> -1902,6
> > +1991,7 @@ static int sdma_probe(struct platform_device *pdev)
> >
> > dma_cap_set(DMA_SLAVE, sdma->dma_device.cap_mask);
> > dma_cap_set(DMA_CYCLIC, sdma->dma_device.cap_mask);
> > + dma_cap_set(DMA_MEMCPY, sdma->dma_device.cap_mask);
> >
> > INIT_LIST_HEAD(&sdma->dma_device.channels);
> > /* Initialize channel parameters */
> > @@ -1968,9 +2058,11 @@ static int sdma_probe(struct platform_device
> *pdev)
> > sdma->dma_device.dst_addr_widths = SDMA_DMA_BUSWIDTHS;
> > sdma->dma_device.directions = SDMA_DMA_DIRECTIONS;
> > sdma->dma_device.residue_granularity =
> > DMA_RESIDUE_GRANULARITY_SEGMENT;
> > + sdma->dma_device.device_prep_dma_memcpy = sdma_prep_memcpy;
> > sdma->dma_device.device_issue_pending = sdma_issue_pending;
> > sdma->dma_device.dev->dma_parms = &sdma->dma_parms;
> > - dma_set_max_seg_size(sdma->dma_device.dev, 65535);
> > + sdma->dma_device.copy_align = DMAENGINE_ALIGN_4_BYTES;
> > + dma_set_max_seg_size(sdma->dma_device.dev, SDMA_BD_MAX_CNT);
>
> this line should not be part of this patch
>
> --
> ~Vinod