diff options
| author | Paul Cercueil <paul@crapouillou.net> | 2018-08-29 23:32:47 +0200 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2018-09-11 12:59:26 +0530 |
| commit | 5eed7d84bcc0fac063e7c4cbd3ffc9990268049d (patch) | |
| tree | 46fcb44d60ee5dcb62d4bbb3a510d64e1ba89727 /drivers/dma | |
| parent | 33633583a23aff572ff6b46a6bc57808b9c9872e (diff) | |
| download | linux-5eed7d84bcc0fac063e7c4cbd3ffc9990268049d.tar.bz2 | |
dmaengine: dma-jz4780: Use 4-word descriptors
The only information we use in the 8-word version of the hardware DMA
descriptor that is not present in the 4-word version is the transfer
type, aka. the ID of the source or recipient device.
Since the transfer type will never change for a DMA channel in use,
we can just set it once for all in the corresponding DMA register
before starting any transfer.
This has several benefits:
* the driver will handle twice as many hardware DMA descriptors;
* the driver is closer to support the JZ4740, which only supports 4-word
hardware DMA descriptors;
* the JZ4770 SoC needs the transfer type to be set in the corresponding
DMA register anyway, even if 8-word descriptors are in use.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Mathieu Malaterre <malat@debian.org>
Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/dma')
| -rw-r--r-- | drivers/dma/dma-jz4780.c | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/drivers/dma/dma-jz4780.c b/drivers/dma/dma-jz4780.c index adf4d5efced6..7683de9fb9ee 100644 --- a/drivers/dma/dma-jz4780.c +++ b/drivers/dma/dma-jz4780.c @@ -95,17 +95,12 @@ * @dtc: transfer count (number of blocks of the transfer size specified in DCM * to transfer) in the low 24 bits, offset of the next descriptor from the * descriptor base address in the upper 8 bits. - * @sd: target/source stride difference (in stride transfer mode). - * @drt: request type */ struct jz4780_dma_hwdesc { uint32_t dcm; uint32_t dsa; uint32_t dta; uint32_t dtc; - uint32_t sd; - uint32_t drt; - uint32_t reserved[2]; }; /* Size of allocations for hardware descriptor blocks. */ @@ -281,7 +276,6 @@ static int jz4780_dma_setup_hwdesc(struct jz4780_dma_chan *jzchan, desc->dcm = JZ_DMA_DCM_SAI; desc->dsa = addr; desc->dta = config->dst_addr; - desc->drt = jzchan->transfer_type; width = config->dst_addr_width; maxburst = config->dst_maxburst; @@ -289,7 +283,6 @@ static int jz4780_dma_setup_hwdesc(struct jz4780_dma_chan *jzchan, desc->dcm = JZ_DMA_DCM_DAI; desc->dsa = config->src_addr; desc->dta = addr; - desc->drt = jzchan->transfer_type; width = config->src_addr_width; maxburst = config->src_maxburst; @@ -434,9 +427,10 @@ static struct dma_async_tx_descriptor *jz4780_dma_prep_dma_memcpy( tsz = jz4780_dma_transfer_size(dest | src | len, &jzchan->transfer_shift); + jzchan->transfer_type = JZ_DMA_DRT_AUTO; + desc->desc[0].dsa = src; desc->desc[0].dta = dest; - desc->desc[0].drt = JZ_DMA_DRT_AUTO; desc->desc[0].dcm = JZ_DMA_DCM_TIE | JZ_DMA_DCM_SAI | JZ_DMA_DCM_DAI | tsz << JZ_DMA_DCM_TSZ_SHIFT | JZ_DMA_WIDTH_32_BIT << JZ_DMA_DCM_SP_SHIFT | @@ -491,9 +485,12 @@ static void jz4780_dma_begin(struct jz4780_dma_chan *jzchan) (jzchan->curr_hwdesc + 1) % jzchan->desc->count; } - /* Use 8-word descriptors. */ - jz4780_dma_chn_writel(jzdma, jzchan->id, - JZ_DMA_REG_DCS, JZ_DMA_DCS_DES8); + /* Use 4-word descriptors. */ + jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DCS, 0); + + /* Set transfer type. */ + jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DRT, + jzchan->transfer_type); /* Write descriptor address and initiate descriptor fetch. */ desc_phys = jzchan->desc->desc_phys + @@ -503,7 +500,7 @@ static void jz4780_dma_begin(struct jz4780_dma_chan *jzchan) /* Enable the channel. */ jz4780_dma_chn_writel(jzdma, jzchan->id, JZ_DMA_REG_DCS, - JZ_DMA_DCS_DES8 | JZ_DMA_DCS_CTE); + JZ_DMA_DCS_CTE); } static void jz4780_dma_issue_pending(struct dma_chan *chan) |