On Thu, Aug 20, 2015 at 02:19:46PM -0000, Michal Suchanek wrote: > 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@xxxxxxxxx> > --- > drivers/spi/spi-sun4i.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/spi/spi-sun4i.c b/drivers/spi/spi-sun4i.c > index 48532ec..707f61b 100644 > --- a/drivers/spi/spi-sun4i.c > +++ b/drivers/spi/spi-sun4i.c > @@ -178,6 +178,8 @@ static int sun4i_spi_transfer_one(struct spi_master *master, > /* We don't support transfer larger than the FIFO */ > if (tfr->len > SUN4I_FIFO_DEPTH) > return -EINVAL; > + if (tfr->tx_buf && tfr->len => SUN4I_FIFO_DEPTH) > + return -EINVAL; Shouldn't you fix the condition just above instead? > > reinit_completion(&sspi->done); > sspi->tx_buf = tfr->tx_buf; > @@ -271,7 +273,9 @@ static int sun4i_spi_transfer_one(struct spi_master *master, > 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); > + /* Filling the fifo fully causes timeout for some reason > + * at least on spi2 on a10s */ Please use the proper comment style. And it only happens on that particular SPI controller and SoC combination? > + sun4i_spi_fill_fifo(sspi, SUN4I_FIFO_DEPTH - 1); > > /* Enable the interrupts */ > sun4i_spi_write(sspi, SUN4I_INT_CTL_REG, SUN4I_INT_CTL_TC); > -- > 2.1.4 > -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com
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