[PATCH 8/8] spi: sirf: make DMA transfer mode optional

[Barry Song]

From: Qipan Li <Qipan.Li at csr.com>

some customers want a pure PIO transfer mode even though DMA mode is
supported. here we give them a Kconfig option, but still keep the DMA
enabled in default.

Signed-off-by: Qipan Li <Qipan.Li at csr.com>
Signed-off-by: Barry Song <Baohua.Song at csr.com>
---
 drivers/spi/Kconfig    | 10 ++++++++++
 drivers/spi/spi-sirf.c | 11 ++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 62e2242..0f84bd8 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -477,6 +477,16 @@ config SPI_SIRF
 	help
 	  SPI driver for CSR SiRFprimaII SoCs
 
+config SPI_SIRF_DMA
+	bool "CSR SiRFprimaII/AtlasVI SPI DMA mode support"
+	depends on SPI_SIRF
+	default y
+	help
+	  CSR SPI driver support DMA and PIO mode, select it let SPI driver support DMA mode
+	  deselect it let SPI controller in PIO mode.
+	  In CSR SPI driver distinguish the config to decide what transfer mode use.
+	  Default configure value is y, if want pure PIO mode deselect it will be OK.
+
 config SPI_SUN4I
 	tristate "Allwinner A10 SoCs SPI controller"
 	depends on ARCH_SUNXI || COMPILE_TEST
diff --git a/drivers/spi/spi-sirf.c b/drivers/spi/spi-sirf.c
index 67d07b2..f934159 100644
--- a/drivers/spi/spi-sirf.c
+++ b/drivers/spi/spi-sirf.c
@@ -333,6 +333,7 @@ static void spi_sirfsoc_cmd_transfer(struct spi_device *spi,
 	sspi->left_rx_word -= t->len;
 }
 
+#ifdef CONFIG_SPI_SIRF_DMA
 static void spi_sirfsoc_dma_transfer(struct spi_device *spi,
 	struct spi_transfer *t)
 {
@@ -407,6 +408,7 @@ static void spi_sirfsoc_dma_transfer(struct spi_device *spi,
 	if (sspi->left_tx_word >= SIRFSOC_SPI_DAT_FRM_LEN_MAX)
 		writel(0, sspi->base + SIRFSOC_SPI_TX_RX_EN);
 }
+#endif
 
 static void spi_sirfsoc_pio_transfer(struct spi_device *spi,
 		struct spi_transfer *t)
@@ -474,8 +476,10 @@ static int spi_sirfsoc_transfer(struct spi_device *spi, struct spi_transfer *t)
 	 */
 	if (sspi->tx_by_cmd)
 		spi_sirfsoc_cmd_transfer(spi, t);
+#ifdef CONFIG_SPI_SIRF_DMA
 	else if (IS_DMA_VALID(t))
 		spi_sirfsoc_dma_transfer(spi, t);
+#endif
 	else
 		spi_sirfsoc_pio_transfer(spi, t);
 
@@ -526,6 +530,11 @@ spi_sirfsoc_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 	u32 regval;
 	u32 txfifo_ctrl, rxfifo_ctrl;
 	u32 fifo_size = SIRFSOC_SPI_FIFO_SIZE / 4;
+#ifdef CONFIG_SPI_SIRF_DMA
+	int spi_use_dma = 1;
+#else
+	int spi_use_dma = 0;
+#endif
 
 	sspi = spi_master_get_devdata(spi->master);
 
@@ -610,7 +619,7 @@ spi_sirfsoc_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 	regval |= SIRFSOC_SPI_CS_IO_MODE;
 	writel(regval, sspi->base + SIRFSOC_SPI_CTRL);
 
-	if (IS_DMA_VALID(t)) {
+	if (spi_use_dma && IS_DMA_VALID(t)) {
 		/* Enable DMA mode for RX, TX */
 		writel(0, sspi->base + SIRFSOC_SPI_TX_DMA_IO_CTRL);
 		writel(SIRFSOC_SPI_RX_DMA_FLUSH,
-- 
2.1.0



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