[PATCH 02/10] dmaengine: sun6i: Correct burst length field offsets for H3
From: Maxime Ripard <hidden>
Date: 2017-09-04 07:59:38
Also in:
linux-devicetree, lkml
On Mon, Sep 04, 2017 at 12:40:53AM +0200, Stefan Br?ns wrote:
quoted hunk ↗ jump to hunk
For the H3, the burst lengths field offsets in the channel configuration register differs from earlier SoC generations. Using the A31 register macros actually configured the H3 controller do to bursts of length 1 always, which although working leads to higher bus utilisation. Signed-off-by: Stefan Br?ns <redacted> --- drivers/dma/sun6i-dma.c | 28 +++++++++++++++++++++------- 1 file changed, 21 insertions(+), 7 deletions(-)diff --git a/drivers/dma/sun6i-dma.c b/drivers/dma/sun6i-dma.c index 1d9b3be30d22..f1a139f0102f 100644 --- a/drivers/dma/sun6i-dma.c +++ b/drivers/dma/sun6i-dma.c@@ -68,13 +68,15 @@ #define DMA_CHAN_CFG_SRC_DRQ(x) ((x) & 0x1f) #define DMA_CHAN_CFG_SRC_IO_MODE BIT(5) #define DMA_CHAN_CFG_SRC_LINEAR_MODE (0 << 5) -#define DMA_CHAN_CFG_SRC_BURST(x) (((x) & 0x3) << 7) +#define DMA_CHAN_CFG_SRC_BURST_A31(x) (((x) & 0x3) << 7) +#define DMA_CHAN_CFG_SRC_BURST_H3(x) (((x) & 0x3) << 6) #define DMA_CHAN_CFG_SRC_WIDTH(x) (((x) & 0x3) << 9) #define DMA_CHAN_CFG_DST_DRQ(x) (DMA_CHAN_CFG_SRC_DRQ(x) << 16) #define DMA_CHAN_CFG_DST_IO_MODE (DMA_CHAN_CFG_SRC_IO_MODE << 16) #define DMA_CHAN_CFG_DST_LINEAR_MODE (DMA_CHAN_CFG_SRC_LINEAR_MODE << 16) -#define DMA_CHAN_CFG_DST_BURST(x) (DMA_CHAN_CFG_SRC_BURST(x) << 16) +#define DMA_CHAN_CFG_DST_BURST_A31(x) (DMA_CHAN_CFG_SRC_BURST_A31(x) << 16) +#define DMA_CHAN_CFG_DST_BURST_H3(x) (DMA_CHAN_CFG_SRC_BURST_H3(x) << 16) #define DMA_CHAN_CFG_DST_WIDTH(x) (DMA_CHAN_CFG_SRC_WIDTH(x) << 16) #define DMA_CHAN_CUR_SRC 0x10@@ -554,11 +556,17 @@ static int set_config(struct sun6i_dma_dev *sdev, if (dst_width < 0) return dst_width; - *p_cfg = DMA_CHAN_CFG_SRC_BURST(src_burst) | - DMA_CHAN_CFG_SRC_WIDTH(src_width) | - DMA_CHAN_CFG_DST_BURST(dst_burst) | + *p_cfg = DMA_CHAN_CFG_SRC_WIDTH(src_width) | DMA_CHAN_CFG_DST_WIDTH(dst_width); + if (sdev->cfg->dmac_variant == DMAC_VARIANT_H3) { + *p_cfg |= DMA_CHAN_CFG_SRC_BURST_H3(src_burst) | + DMA_CHAN_CFG_DST_BURST_H3(dst_burst); + } else { + *p_cfg |= DMA_CHAN_CFG_SRC_BURST_A31(src_burst) | + DMA_CHAN_CFG_DST_BURST_A31(dst_burst); + } +
I guess we have two options to support that properly. We could either have a different function that would generate that register value based on the parameters we have, or duplicate the set_config function entirely, with function pointer stored in the configuration. I think I prefer the former, as it reduces the code duplication. Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 801 bytes Desc: not available URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20170904/e90a7e7b/attachment-0001.sig>