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dmaengine: hdmac: Add scatter-gathered memset support

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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@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Maxime Ripard 2015-10-22 11:41:00 +02:00 committed by Vinod Koul
parent ce2a673d66
commit 67d25f0d4e
1 changed files with 79 additions and 0 deletions
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79
drivers/dma/at_hdmac.c
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@ -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;
}