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Subject[PATCH 2/7] spi: rockchip: adjust dma watermark and burstlen
Date
From: Huibin Hong <huibin.hong@rock-chips.com>

Signal tx dma when spi fifo is less than half full,
and limit tx bursts to half the fifo length.

Clamp rx burst length to 1 to avoid alignment issues.

Signed-off-by: Huibin Hong <huibin.hong@rock-chips.com>
Signed-off-by: Emil Renner Berthing <kernel@esmil.dk>
---
drivers/spi/spi-rockchip.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
index 185bbdce62b1..ede3002215cd 100644
--- a/drivers/spi/spi-rockchip.c
+++ b/drivers/spi/spi-rockchip.c
@@ -458,10 +458,7 @@ static int rockchip_spi_prepare_dma(struct rockchip_spi *rs)
rxconf.direction = rs->dma_rx.direction;
rxconf.src_addr = rs->dma_rx.addr;
rxconf.src_addr_width = rs->n_bytes;
- if (rs->dma_caps.max_burst > 4)
- rxconf.src_maxburst = 4;
- else
- rxconf.src_maxburst = 1;
+ rxconf.src_maxburst = 1;
dmaengine_slave_config(rs->dma_rx.ch, &rxconf);

rxdesc = dmaengine_prep_slave_sg(
@@ -480,10 +477,7 @@ static int rockchip_spi_prepare_dma(struct rockchip_spi *rs)
txconf.direction = rs->dma_tx.direction;
txconf.dst_addr = rs->dma_tx.addr;
txconf.dst_addr_width = rs->n_bytes;
- if (rs->dma_caps.max_burst > 4)
- txconf.dst_maxburst = 4;
- else
- txconf.dst_maxburst = 1;
+ txconf.dst_maxburst = rs->fifo_len / 2;
dmaengine_slave_config(rs->dma_tx.ch, &txconf);

txdesc = dmaengine_prep_slave_sg(
@@ -581,7 +575,7 @@ static void rockchip_spi_config(struct rockchip_spi *rs)
writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_TXFTLR);
writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_RXFTLR);

- writel_relaxed(0, rs->regs + ROCKCHIP_SPI_DMATDLR);
+ writel_relaxed(rs->fifo_len / 2 - 1, rs->regs + ROCKCHIP_SPI_DMATDLR);
writel_relaxed(0, rs->regs + ROCKCHIP_SPI_DMARDLR);
writel_relaxed(dmacr, rs->regs + ROCKCHIP_SPI_DMACR);

--
2.19.1
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