spi/pxa2xx: add support for DMA engine

To be able to use DMA with this driver on non-PXA platforms we implement
support for the generic DMA engine API. This lets user to use different DMA
engines with little or no modification to the driver.

Request lines and channel numbers can be passed to the driver from the
platform specific data.

The DMA engine implementation will be selected by default even on PXA
platform. User can select the legacy DMA API by enabling Kconfig option
CONFIG_SPI_PXA2XX_PXADMA.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Lu Cao <lucao@marvell.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 31 insertions, 1 deletions

diff --git a/drivers/spi/spi-pxa2xx.h b/drivers/spi/spi-pxa2xx.h
index 0a98905c916e..97ff4717e6ac 100644
--- a/drivers/spi/spi-pxa2xx.h
+++ b/drivers/spi/spi-pxa2xx.h
@@ -10,11 +10,15 @@
 #ifndef SPI_PXA2XX_H
 #define SPI_PXA2XX_H
 
+#include <linux/atomic.h>
+#include <linux/dmaengine.h>
 #include <linux/errno.h>
 #include <linux/io.h>
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/pxa2xx_ssp.h>
+#include <linux/scatterlist.h>
+#include <linux/sizes.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/pxa2xx_spi.h>
 
@@ -53,6 +57,16 @@ struct driver_data {
         /* Message Transfer pump */
         struct tasklet_struct pump_transfers;
 
+        /* DMA engine support */
+        struct dma_chan *rx_chan;
+        struct dma_chan *tx_chan;
+        struct sg_table rx_sgt;
+        struct sg_table tx_sgt;
+        int rx_nents;
+        int tx_nents;
+        void *dummy;
+        atomic_t dma_running;
+
         /* Current message transfer state info */
         struct spi_message *cur_msg;
         struct spi_transfer *cur_transfer;
@@ -116,7 +130,6 @@ DEFINE_SSP_REG(SSPSP, 0x2c)
 #define DONE_STATE ((void *)2)
 #define ERROR_STATE ((void *)-1)
 
-#define MAX_DMA_LEN             8191
 #define IS_DMA_ALIGNED(x)       IS_ALIGNED((unsigned long)(x), DMA_ALIGNMENT)
 #define DMA_ALIGNMENT           8
 
@@ -142,7 +155,24 @@ static inline void write_SSSR_CS(struct driver_data *drv_data, u32 val)
 extern int pxa2xx_spi_flush(struct driver_data *drv_data);
 extern void *pxa2xx_spi_next_transfer(struct driver_data *drv_data);
 
+/*
+ * Select the right DMA implementation.
+ */
 #if defined(CONFIG_SPI_PXA2XX_PXADMA)
+#define SPI_PXA2XX_USE_DMA      1
+#define MAX_DMA_LEN             8191
+#define DEFAULT_DMA_CR1         (SSCR1_TSRE | SSCR1_RSRE | SSCR1_TINTE)
+#elif defined(CONFIG_SPI_PXA2XX_DMA)
+#define SPI_PXA2XX_USE_DMA      1
+#define MAX_DMA_LEN             SZ_64K
+#define DEFAULT_DMA_CR1         (SSCR1_TSRE | SSCR1_RSRE | SSCR1_TRAIL)
+#else
+#undef SPI_PXA2XX_USE_DMA
+#define MAX_DMA_LEN             0
+#define DEFAULT_DMA_CR1         0
+#endif
+
+#ifdef SPI_PXA2XX_USE_DMA
 extern bool pxa2xx_spi_dma_is_possible(size_t len);
 extern int pxa2xx_spi_map_dma_buffers(struct driver_data *drv_data);
 extern irqreturn_t pxa2xx_spi_dma_transfer(struct driver_data *drv_data);