[PATCH] spi: qup: Add DMA capabilities
From: Ivan T. Ivanov <hidden>
Date: 2014-07-02 14:27:04
Also in:
linux-arm-msm, linux-spi, lkml
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 <redacted> --- .../devicetree/bindings/spi/qcom,spi-qup.txt | 10 + drivers/spi/spi-qup.c | 361 ++++++++++++++++++-- 2 files changed, 350 insertions(+), 21 deletions(-)
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quoted hunk ↗ jump to hunk
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; };
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quoted hunk ↗ jump to hunk
@@ -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