Commit c64e1265 authored May 27, 2016 by Dan O'Donovan Committed by Mark Brown May 30, 2016

spi: pxa2xx: use DMA by default if supported



Currently, even if the PXA2xx SPI master supports DMA, it won't be
enabled unless (i) the slave device is enumerated through ACPI, or
(ii) the slave device is registered with board-specific
controller_data specified.  Even then, there isn't a field in the
controller_data that explicitly enables dma - it just gets enabled
if the master supports it and controller_data is non-NULL.

This means that drivers which register SPI devices on a bus without
awareness of this controller cannot avail of DMA performance gains.

This patch allows DMA transfers to be used if supported.

Signed-off-by: Dan O'Donovan <dan@emutex.com>
Reviewed-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

parent 1a695a90

drivers/spi/spi-pxa2xx.c

+1 −9

Original line number	Diff line number	Diff line
		@@ -1240,7 +1240,7 @@ static int setup(struct spi_device *spi)
		chip->frm = spi->chip_select;
		} else
		chip->gpio_cs = -1;
		chip->enable_dma = 0;
		chip->enable_dma = drv_data->master_info->enable_dma;
		chip->timeout = TIMOUT_DFLT;
		}

		@@ -1259,17 +1259,9 @@ static int setup(struct spi_device *spi)
		tx_hi_thres = chip_info->tx_hi_threshold;
		if (chip_info->rx_threshold)
		rx_thres = chip_info->rx_threshold;
		chip->enable_dma = drv_data->master_info->enable_dma;
		chip->dma_threshold = 0;
		if (chip_info->enable_loopback)
		chip->cr1 = SSCR1_LBM;
		} else if (ACPI_HANDLE(&spi->dev)) {
		/*
		* Slave devices enumerated from ACPI namespace don't
		* usually have chip_info but we still might want to use
		* DMA with them.
		*/
		chip->enable_dma = drv_data->master_info->enable_dma;
		}

		chip->lpss_rx_threshold = SSIRF_RxThresh(rx_thres);

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