lkml.org 
[lkml]   [2016]   [Aug]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.4 43/68] spi: sun4i: fix FIFO limit
    Date
    4.4-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Michal Suchanek <hramrach@gmail.com>

    commit 6d9fe44bd73d567d04d3a68a2d2fa521ab9532f2 upstream.

    When testing SPI without DMA I noticed that filling the FIFO on the
    spi controller causes timeout.

    Always leave room for one byte in the FIFO.

    Signed-off-by: Michal Suchanek <hramrach@gmail.com>
    Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
    Signed-off-by: Mark Brown <broonie@kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    drivers/spi/spi-sun4i.c | 13 ++++++++++---
    1 file changed, 10 insertions(+), 3 deletions(-)

    --- a/drivers/spi/spi-sun4i.c
    +++ b/drivers/spi/spi-sun4i.c
    @@ -177,7 +177,10 @@ static int sun4i_spi_transfer_one(struct

    /* We don't support transfer larger than the FIFO */
    if (tfr->len > SUN4I_FIFO_DEPTH)
    - return -EINVAL;
    + return -EMSGSIZE;
    +
    + if (tfr->tx_buf && tfr->len >= SUN4I_FIFO_DEPTH)
    + return -EMSGSIZE;

    reinit_completion(&sspi->done);
    sspi->tx_buf = tfr->tx_buf;
    @@ -270,8 +273,12 @@ static int sun4i_spi_transfer_one(struct
    sun4i_spi_write(sspi, SUN4I_BURST_CNT_REG, SUN4I_BURST_CNT(tfr->len));
    sun4i_spi_write(sspi, SUN4I_XMIT_CNT_REG, SUN4I_XMIT_CNT(tx_len));

    - /* Fill the TX FIFO */
    - sun4i_spi_fill_fifo(sspi, SUN4I_FIFO_DEPTH);
    + /*
    + * Fill the TX FIFO
    + * Filling the FIFO fully causes timeout for some reason
    + * at least on spi2 on A10s
    + */
    + sun4i_spi_fill_fifo(sspi, SUN4I_FIFO_DEPTH - 1);

    /* Enable the interrupts */
    sun4i_spi_write(sspi, SUN4I_INT_CTL_REG, SUN4I_INT_CTL_TC);

    \
     
     \ /
      Last update: 2016-08-08 22:21    [W:3.414 / U:0.004 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site