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Commit 67d25f0d authored by Maxime Ripard's avatar Maxime Ripard Committed by Vinod Koul
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dmaengine: hdmac: Add scatter-gathered memset support 



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: default avatarMaxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: default avatarNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent ce2a673d

drivers/dma/at_hdmac.c

+79 −0
Original line number Diff line number Diff line
@@ -986,6 +986,83 @@ atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value, 
	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;

	}