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dma: mmp_pdma: add support for byte-aligned transfers 

The PXA DMA controller has a DALGN register which allows for
byte-aligned DMA transfers. Use it in case any of the transfer
descriptors is not aligned to a mask of ~0x7.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
hifive-unleashed-5.1
Daniel Mack 2013-08-10 18:52:22 +02:00 committed by Vinod Koul
parent 8fd6aac3a8
commit 6fc4573c4e
1 changed files with 16 additions and 1 deletions
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17
drivers/dma/mmp_pdma.c
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@ -109,6 +109,7 @@ struct mmp_pdma_chan {
struct list_head chain_pending; /* Link descriptors queue for pending */
struct list_head chain_running; /* Link descriptors queue for running */
bool idle; /* channel statue machine */
bool byte_align;
struct dma_pool *desc_pool; /* Descriptors pool */
};
@ -142,7 +143,7 @@ static void set_desc(struct mmp_pdma_phy *phy, dma_addr_t addr)
static void enable_chan(struct mmp_pdma_phy *phy)
{
u32 reg;
u32 reg, dalgn;
if (!phy->vchan)
return;
@ -150,6 +151,13 @@ static void enable_chan(struct mmp_pdma_phy *phy)
reg = DRCMR(phy->vchan->drcmr);
writel(DRCMR_MAPVLD | phy->idx, phy->base + reg);
dalgn = readl(phy->base + DALGN);
if (phy->vchan->byte_align)
dalgn |= 1 << phy->idx;
else
dalgn &= ~(1 << phy->idx);
writel(dalgn, phy->base + DALGN);
reg = (phy->idx << 2) + DCSR;
writel(readl(phy->base + reg) | DCSR_RUN,
phy->base + reg);
@ -455,6 +463,7 @@ mmp_pdma_prep_memcpy(struct dma_chan *dchan,
return NULL;
chan = to_mmp_pdma_chan(dchan);
chan->byte_align = false;
if (!chan->dir) {
chan->dir = DMA_MEM_TO_MEM;
@ -471,6 +480,8 @@ mmp_pdma_prep_memcpy(struct dma_chan *dchan,
}
copy = min_t(size_t, len, PDMA_MAX_DESC_BYTES);
if (dma_src & 0x7 || dma_dst & 0x7)
chan->byte_align = true;
new->desc.dcmd = chan->dcmd | (DCMD_LENGTH & copy);
new->desc.dsadr = dma_src;
@ -530,12 +541,16 @@ mmp_pdma_prep_slave_sg(struct dma_chan *dchan, struct scatterlist *sgl,
if ((sgl == NULL) || (sg_len == 0))
return NULL;
chan->byte_align = false;
for_each_sg(sgl, sg, sg_len, i) {
addr = sg_dma_address(sg);
avail = sg_dma_len(sgl);
do {
len = min_t(size_t, avail, PDMA_MAX_DESC_BYTES);
if (addr & 0x7)
chan->byte_align = true;
/* allocate and populate the descriptor */
new = mmp_pdma_alloc_descriptor(chan);