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    Subject[PATCH v3 8/9] spi: rockchip: modify DMA max burst to 1
    Date
    From: Addy Ke <addy.ke@rock-chips.com>

    Generic dma controller on Rockchips' platform cannot support
    DMAFLUSHP instruction which make dma to flush the req of non-aligned
    or non-multiple of what we need. That will cause an unrecoverable
    dma bus error. The saftest way is to set dma max burst to 1.

    Signed-off-by: Addy ke <addy.ke@rock-chips.com>
    Fixes: 64e36824b32b06 ("spi/rockchip: add driver for Rockchip...")
    Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
    cc: Heiko Stuebner <heiko@sntech.de>
    cc: Olof Johansson <olof@lixom.net>
    cc: Doug Anderson <dianders@chromium.org>
    cc: Sonny Rao <sonnyrao@chromium.org>
    ---

    Changes in v3: None
    Changes in v2: None
    Changes in v1: None

    drivers/spi/spi-rockchip.c | 16 ++++++++++++++--
    1 file changed, 14 insertions(+), 2 deletions(-)

    diff --git a/drivers/spi/spi-rockchip.c b/drivers/spi/spi-rockchip.c
    index 68e7efe..3748ca5 100644
    --- a/drivers/spi/spi-rockchip.c
    +++ b/drivers/spi/spi-rockchip.c
    @@ -199,6 +199,8 @@ struct rockchip_spi {
    struct sg_table rx_sg;
    struct rockchip_spi_dma_data dma_rx;
    struct rockchip_spi_dma_data dma_tx;
    + int quirk;
    +#define ROCKCHIP_SPI_BORKEN_BURST_LEN (1<<0) /* broken burst len*/
    };

    static inline void spi_enable_chip(struct rockchip_spi *rs, int enable)
    @@ -449,7 +451,10 @@ static void 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;
    - rxconf.src_maxburst = rs->n_bytes;
    + if (rs->quirk & ROCKCHIP_SPI_BORKEN_BURST_LEN)
    + rxconf.src_maxburst = 1;
    + else
    + rxconf.src_maxburst = rs->n_bytes;
    dmaengine_slave_config(rs->dma_rx.ch, &rxconf);

    rxdesc = dmaengine_prep_slave_sg(
    @@ -466,7 +471,10 @@ static void 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;
    - txconf.dst_maxburst = rs->n_bytes;
    + if (rs->quirk & ROCKCHIP_SPI_BORKEN_BURST_LEN)
    + txconf.dst_maxburst = 1;
    + else
    + txconf.dst_maxburst = rs->n_bytes;
    dmaengine_slave_config(rs->dma_tx.ch, &txconf);

    txdesc = dmaengine_prep_slave_sg(
    @@ -699,6 +707,10 @@ static int rockchip_spi_probe(struct platform_device *pdev)
    goto err_get_fifo_len;
    }

    + if (of_property_read_bool(pdev->dev.of_node,
    + "rockchip,spi-broken-burst-len"))
    + rs->quirk |= ROCKCHIP_SPI_BORKEN_BURST_LEN;
    +
    spin_lock_init(&rs->lock);

    pm_runtime_set_active(&pdev->dev);
    --
    2.3.7



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