Hi Andy,
Just few comments.
On Thu, 2014-06-26 at 16:06 -0500, Andy Gross wrote:
> This patch adds DMA capabilities to the spi-qup driver. If DMA channels are
> present, the QUP will use DMA instead of block mode for transfers to/from SPI
> peripherals for transactions larger than the length of a block.
>
> Signed-off-by: Andy Gross <agross@xxxxxxxxxxxxxx>
> ---
> .../devicetree/bindings/spi/qcom,spi-qup.txt | 10 +
> drivers/spi/spi-qup.c | 361 ++++++++++++++++++--
> 2 files changed, 350 insertions(+), 21 deletions(-)
>
<snip>
> diff --git a/drivers/spi/spi-qup.c b/drivers/spi/spi-qup.c
> index fc1de86..9b01db5 100644
> --- a/drivers/spi/spi-qup.c
> +++ b/drivers/spi/spi-qup.c
> @@ -22,6 +22,8 @@
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> #include <linux/spi/spi.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
>
> #define QUP_CONFIG 0x0000
> #define QUP_STATE 0x0004
> @@ -116,6 +118,8 @@
>
> #define SPI_NUM_CHIPSELECTS 4
>
> +#define SPI_MAX_XFER (SZ_64K - 64)
> +
> /* high speed mode is when bus rate is greater then 26MHz */
> #define SPI_HS_MIN_RATE 26000000
> #define SPI_MAX_RATE 50000000
> @@ -142,6 +146,17 @@ struct spi_qup {
> int w_size; /* bytes per SPI word */
> int tx_bytes;
> int rx_bytes;
> +
> + int use_dma;
> +
> + struct dma_chan *rx_chan;
> + struct dma_slave_config rx_conf;
> + struct dma_chan *tx_chan;
> + struct dma_slave_config tx_conf;
> + dma_addr_t rx_dma;
> + dma_addr_t tx_dma;
DMA addresses seems unused.
> + void *dummy;
This is not so dummy, probably 'spare'.
> + atomic_t dma_outstanding;
> };
<snip>
>
>
> @@ -632,6 +896,56 @@ static int spi_qup_probe(struct platform_device *pdev)
> writel_relaxed(SPI_ERROR_CLK_UNDER_RUN | SPI_ERROR_CLK_OVER_RUN,
> base + SPI_ERROR_FLAGS_EN);
>
> + /* allocate dma resources, if available */
> + controller->rx_chan = dma_request_slave_channel(&pdev->dev, "rx");
> + if (controller->rx_chan) {
> + controller->tx_chan =
> + dma_request_slave_channel(&pdev->dev, "tx");
> +
> + if (!controller->tx_chan) {
> + dev_err(&pdev->dev, "Failed to allocate dma tx chan");
> + dma_release_channel(controller->rx_chan);
There is no point to go further with DMA configuration
if there are no channels, right?
> + }
> +
> + /* set DMA parameters */
> + controller->rx_conf.device_fc = 1;
> + controller->rx_conf.src_addr = res->start + QUP_INPUT_FIFO;
> + controller->rx_conf.src_maxburst = controller->in_blk_sz;
> +
> + controller->tx_conf.device_fc = 1;
> + controller->tx_conf.dst_addr = res->start + QUP_OUTPUT_FIFO;
> + controller->tx_conf.dst_maxburst = controller->out_blk_sz;
> +
Please, could you share blsp2_bam device node configuration?
I would like to test these changes.
Regards,
Ivan
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