Le 22/10/2015 11:41, Maxime Ripard a écrit :
> Just like memset support, the HDMAC might be used to do a memset over a
> discontiguous memory area.
>
> In such a case, we'll just build up a chain of memset descriptors over the
> contiguous chunks of memory to set, in order to allow such a support.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
Yep, seems good!
Acked-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
Thanks Maxime, bye.
> ---
> drivers/dma/at_hdmac.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 79 insertions(+)
>
> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
> index cad18f3660ae..4e55239c7a30 100644
> --- a/drivers/dma/at_hdmac.c
> +++ b/drivers/dma/at_hdmac.c
> @@ -986,6 +986,83 @@ err_free_buffer:
> return NULL;
> }
>
> +static struct dma_async_tx_descriptor *
> +atc_prep_dma_memset_sg(struct dma_chan *chan,
> + struct scatterlist *sgl,
> + unsigned int sg_len, int value,
> + unsigned long flags)
> +{
> + struct at_dma_chan *atchan = to_at_dma_chan(chan);
> + struct at_dma *atdma = to_at_dma(chan->device);
> + struct at_desc *desc = NULL, *first = NULL, *prev = NULL;
> + struct scatterlist *sg;
> + void __iomem *vaddr;
> + dma_addr_t paddr;
> + size_t total_len = 0;
> + int i;
> +
> + dev_vdbg(chan2dev(chan), "%s: v0x%x l0x%zx f0x%lx\n", __func__,
> + value, sg_len, flags);
> +
> + if (unlikely(!sgl || !sg_len)) {
> + dev_dbg(chan2dev(chan), "%s: scatterlist is empty!\n",
> + __func__);
> + return NULL;
> + }
> +
> + vaddr = dma_pool_alloc(atdma->memset_pool, GFP_ATOMIC, &paddr);
> + if (!vaddr) {
> + dev_err(chan2dev(chan), "%s: couldn't allocate buffer\n",
> + __func__);
> + return NULL;
> + }
> + *(u32*)vaddr = value;
> +
> + for_each_sg(sgl, sg, sg_len, i) {
> + dma_addr_t dest = sg_dma_address(sg);
> + size_t len = sg_dma_len(sg);
> +
> + dev_vdbg(chan2dev(chan), "%s: d0x%08x, l0x%zx\n",
> + __func__, dest, len);
> +
> + if (!is_dma_fill_aligned(chan->device, dest, 0, len)) {
> + dev_err(chan2dev(chan), "%s: buffer is not aligned\n",
> + __func__);
> + goto err_put_desc;
> + }
> +
> + desc = atc_create_memset_desc(chan, paddr, dest, len);
> + if (!desc)
> + goto err_put_desc;
> +
> + atc_desc_chain(&first, &prev, desc);
> +
> + total_len += len;
> + }
> +
> + /*
> + * Only set the buffer pointers on the last descriptor to
> + * avoid free'ing while we have our transfer still going
> + */
> + desc->memset_paddr = paddr;
> + desc->memset_vaddr = vaddr;
> + desc->memset_buffer = true;
> +
> + first->txd.cookie = -EBUSY;
> + first->total_len = total_len;
> +
> + /* set end-of-link on the descriptor */
> + set_desc_eol(desc);
> +
> + first->txd.flags = flags;
> +
> + return &first->txd;
> +
> +err_put_desc:
> + atc_desc_put(atchan, first);
> + return NULL;
> +}
> +
> /**
> * atc_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction
> * @chan: DMA channel
> @@ -1868,6 +1945,7 @@ static int __init at_dma_probe(struct platform_device *pdev)
> dma_cap_set(DMA_INTERLEAVE, at91sam9g45_config.cap_mask);
> dma_cap_set(DMA_MEMCPY, at91sam9g45_config.cap_mask);
> dma_cap_set(DMA_MEMSET, at91sam9g45_config.cap_mask);
> + dma_cap_set(DMA_MEMSET_SG, at91sam9g45_config.cap_mask);
> dma_cap_set(DMA_PRIVATE, at91sam9g45_config.cap_mask);
> dma_cap_set(DMA_SLAVE, at91sam9g45_config.cap_mask);
> dma_cap_set(DMA_SG, at91sam9g45_config.cap_mask);
> @@ -1989,6 +2067,7 @@ static int __init at_dma_probe(struct platform_device *pdev)
>
> if (dma_has_cap(DMA_MEMSET, atdma->dma_common.cap_mask)) {
> atdma->dma_common.device_prep_dma_memset = atc_prep_dma_memset;
> + atdma->dma_common.device_prep_dma_memset_sg = atc_prep_dma_memset_sg;
> atdma->dma_common.fill_align = DMAENGINE_ALIGN_4_BYTES;
> }
>
>
--
Nicolas Ferre
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