2016-03-22 1:00 GMT+09:00 Akinobu Mita <akinobu.mita@xxxxxxxxx>:
> Currently omap2-mcspi cannot handle dma transfer for vmalloced buffer.
> I hit this problem when using mtdblock on spi-nor.
>
> This lets the SPI core handle the page mapping for dma transfer buffer.
>
> Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
> Cc: Mark Brown <broonie@xxxxxxxxxx>
> ---
> drivers/spi/spi-omap2-mcspi.c | 62 ++++++++++++-------------------------------
> 1 file changed, 17 insertions(+), 45 deletions(-)
>
> diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
> index 0caa3c8..43a02e3 100644
> --- a/drivers/spi/spi-omap2-mcspi.c
> +++ b/drivers/spi/spi-omap2-mcspi.c
> @@ -423,16 +423,12 @@ static void omap2_mcspi_tx_dma(struct spi_device *spi,
>
> if (mcspi_dma->dma_tx) {
> struct dma_async_tx_descriptor *tx;
> - struct scatterlist sg;
>
> dmaengine_slave_config(mcspi_dma->dma_tx, &cfg);
>
> - sg_init_table(&sg, 1);
> - sg_dma_address(&sg) = xfer->tx_dma;
> - sg_dma_len(&sg) = xfer->len;
> -
> - tx = dmaengine_prep_slave_sg(mcspi_dma->dma_tx, &sg, 1,
> - DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
> + tx = dmaengine_prep_slave_sg(mcspi_dma->dma_tx, xfer->tx_sg.sgl,
> + xfer->tx_sg.nents, DMA_MEM_TO_DEV,
> + DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
> if (tx) {
> tx->callback = omap2_mcspi_tx_callback;
> tx->callback_param = spi;
> @@ -478,20 +474,15 @@ omap2_mcspi_rx_dma(struct spi_device *spi, struct spi_transfer *xfer,
>
> if (mcspi_dma->dma_rx) {
> struct dma_async_tx_descriptor *tx;
> - struct scatterlist sg;
>
> dmaengine_slave_config(mcspi_dma->dma_rx, &cfg);
>
> if ((l & OMAP2_MCSPI_CHCONF_TURBO) && mcspi->fifo_depth == 0)
> dma_count -= es;
>
The actual transfer length can be smaller than xfer->len by above line.
And the last word is filled after dma transfer completion.
So this patch is broken. Could you revert remove this from your
development tree?
I don't find a way how to fix it without copy and pasting a lot of
line from spi core.
> - sg_init_table(&sg, 1);
> - sg_dma_address(&sg) = xfer->rx_dma;
> - sg_dma_len(&sg) = dma_count;
> -
> - tx = dmaengine_prep_slave_sg(mcspi_dma->dma_rx, &sg, 1,
> - DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT |
> - DMA_CTRL_ACK);
> + tx = dmaengine_prep_slave_sg(mcspi_dma->dma_rx, xfer->rx_sg.sgl,
> + xfer->rx_sg.nents, DMA_DEV_TO_MEM,
> + DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
> if (tx) {
> tx->callback = omap2_mcspi_rx_callback;
> tx->callback_param = spi;
> @@ -505,8 +496,6 @@ omap2_mcspi_rx_dma(struct spi_device *spi, struct spi_transfer *xfer,
> omap2_mcspi_set_dma_req(spi, 1, 1);
>
> wait_for_completion(&mcspi_dma->dma_rx_completion);
> - dma_unmap_single(mcspi->dev, xfer->rx_dma, count,
> - DMA_FROM_DEVICE);
>
> if (mcspi->fifo_depth > 0)
> return count;
> @@ -619,8 +608,6 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
>
> if (tx != NULL) {
> wait_for_completion(&mcspi_dma->dma_tx_completion);
> - dma_unmap_single(mcspi->dev, xfer->tx_dma, xfer->len,
> - DMA_TO_DEVICE);
>
> if (mcspi->fifo_depth > 0) {
> irqstat_reg = mcspi->base + OMAP2_MCSPI_IRQSTATUS;
> @@ -1087,6 +1074,16 @@ static void omap2_mcspi_cleanup(struct spi_device *spi)
> gpio_free(spi->cs_gpio);
> }
>
> +static bool omap2_mcspi_can_dma(struct spi_master *master,
> + struct spi_device *spi,
> + struct spi_transfer *xfer)
> +{
> + if (xfer->len < DMA_MIN_BYTES)
> + return false;
> +
> + return true;
> +}
> +
> static int omap2_mcspi_work_one(struct omap2_mcspi *mcspi,
> struct spi_device *spi, struct spi_transfer *t)
> {
> @@ -1268,32 +1265,6 @@ static int omap2_mcspi_transfer_one(struct spi_master *master,
> return -EINVAL;
> }
>
> - if (len < DMA_MIN_BYTES)
> - goto skip_dma_map;
> -
> - if (mcspi_dma->dma_tx && tx_buf != NULL) {
> - t->tx_dma = dma_map_single(mcspi->dev, (void *) tx_buf,
> - len, DMA_TO_DEVICE);
> - if (dma_mapping_error(mcspi->dev, t->tx_dma)) {
> - dev_dbg(mcspi->dev, "dma %cX %d bytes error\n",
> - 'T', len);
> - return -EINVAL;
> - }
> - }
> - if (mcspi_dma->dma_rx && rx_buf != NULL) {
> - t->rx_dma = dma_map_single(mcspi->dev, rx_buf, t->len,
> - DMA_FROM_DEVICE);
> - if (dma_mapping_error(mcspi->dev, t->rx_dma)) {
> - dev_dbg(mcspi->dev, "dma %cX %d bytes error\n",
> - 'R', len);
> - if (tx_buf != NULL)
> - dma_unmap_single(mcspi->dev, t->tx_dma,
> - len, DMA_TO_DEVICE);
> - return -EINVAL;
> - }
> - }
> -
> -skip_dma_map:
> return omap2_mcspi_work_one(mcspi, spi, t);
> }
>
> @@ -1377,6 +1348,7 @@ static int omap2_mcspi_probe(struct platform_device *pdev)
> master->transfer_one = omap2_mcspi_transfer_one;
> master->set_cs = omap2_mcspi_set_cs;
> master->cleanup = omap2_mcspi_cleanup;
> + master->can_dma = omap2_mcspi_can_dma;
> master->dev.of_node = node;
> master->max_speed_hz = OMAP2_MCSPI_MAX_FREQ;
> master->min_speed_hz = OMAP2_MCSPI_MAX_FREQ >> 15;
> --
> 2.5.0
>
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