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spi: rspi: Add DMA support for QSPI on R-Car Gen2

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Enable DMA support for QSPI on R-Car Gen2, for Single, Dual, and Quad SPI
Transfers.

Performance figures for reading from a QSPI FLASH driven at 24.375 MHz
on r8a7791/koelsch:
  - Single:  1.1 Mbps PIO, 23 Mbps DMA
  - Dual  : 12.7 Mbps PIO, 48 Mbps DMA
  - Quad  : 13   Mbps PIO, 70 Mbps DMA

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@linaro.org>
This commit is contained in:
Geert Uytterhoeven 2014-06-02 15:38:17 +02:00 committed by Mark Brown
parent 03e627c557
commit 4f12b5e529
1 changed files with 9 additions and 0 deletions
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9
drivers/spi/spi-rspi.c
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@ -642,6 +642,9 @@ static int qspi_transfer_out_in(struct rspi_data *rspi,
qspi_receive_init(rspi);
if (rspi->master->can_dma && __rspi_can_dma(rspi, xfer))
return rspi_dma_transfer(rspi, &xfer->tx_sg, &xfer->rx_sg);
ret = rspi_pio_transfer(rspi, xfer->tx_buf, xfer->rx_buf, xfer->len);
if (ret < 0)
return ret;
@ -656,6 +659,9 @@ static int qspi_transfer_out(struct rspi_data *rspi, struct spi_transfer *xfer)
{
int ret;
if (rspi->master->can_dma && __rspi_can_dma(rspi, xfer))
return rspi_dma_transfer(rspi, &xfer->tx_sg, NULL);
ret = rspi_pio_transfer(rspi, xfer->tx_buf, NULL, xfer->len);
if (ret < 0)
return ret;
@ -668,6 +674,9 @@ static int qspi_transfer_out(struct rspi_data *rspi, struct spi_transfer *xfer)
static int qspi_transfer_in(struct rspi_data *rspi, struct spi_transfer *xfer)
{
if (rspi->master->can_dma && __rspi_can_dma(rspi, xfer))
return rspi_dma_transfer(rspi, NULL, &xfer->rx_sg);
return rspi_pio_transfer(rspi, NULL, xfer->rx_buf, xfer->len);
}