dmaengine: add ep93xx DMA support

The ep93xx DMA controller has 10 independent memory to peripheral (M2P)
channels, and 2 dedicated memory to memory (M2M) channels. M2M channels can
also be used by SPI and IDE to perform DMA transfers to/from their memory
mapped FIFOs.

This driver supports both M2P and M2M channels with DMA_SLAVE, DMA_CYCLIC and
DMA_MEMCPY (M2M only) capabilities.
Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
Signed-off-by: Ryan Mallon <rmallon@gmail.com>
Acked-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

arch/arm/mach-ep93xx/include/mach/dma.h

@@ -15,6 +15,8 @@
 
 #include <linux/list.h>
 #include <linux/types.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
 
 /**
  * struct ep93xx_dma_buffer - Information about a buffer to be transferred
@@ -146,4 +148,89 @@ void ep93xx_dma_m2p_submit_recursive(struct ep93xx_dma_m2p_client *m2p,
  */
 void ep93xx_dma_m2p_flush(struct ep93xx_dma_m2p_client *m2p);
 
+/*
+ * M2P channels.
+ *
+ * Note that these values are also directly used for setting the PPALLOC
+ * register.
+ */
+#define EP93XX_DMA_I2S1		0
+#define EP93XX_DMA_I2S2		1
+#define EP93XX_DMA_AAC1		2
+#define EP93XX_DMA_AAC2		3
+#define EP93XX_DMA_AAC3		4
+#define EP93XX_DMA_I2S3		5
+#define EP93XX_DMA_UART1	6
+#define EP93XX_DMA_UART2	7
+#define EP93XX_DMA_UART3	8
+#define EP93XX_DMA_IRDA		9
+/* M2M channels */
+#define EP93XX_DMA_SSP		10
+#define EP93XX_DMA_IDE		11
+
+/**
+ * struct ep93xx_dma_data - configuration data for the EP93xx dmaengine
+ * @port: peripheral which is requesting the channel
+ * @direction: TX/RX channel
+ * @name: optional name for the channel, this is displayed in /proc/interrupts
+ *
+ * This information is passed as private channel parameter in a filter
+ * function. Note that this is only needed for slave/cyclic channels.  For
+ * memcpy channels %NULL data should be passed.
+ */
+struct ep93xx_dma_data {
+	int				port;
+	enum dma_data_direction		direction;
+	const char			*name;
+};
+
+/**
+ * struct ep93xx_dma_chan_data - platform specific data for a DMA channel
+ * @name: name of the channel, used for getting the right clock for the channel
+ * @base: mapped registers
+ * @irq: interrupt number used by this channel
+ */
+struct ep93xx_dma_chan_data {
+	const char			*name;
+	void __iomem			*base;
+	int				irq;
+};
+
+/**
+ * struct ep93xx_dma_platform_data - platform data for the dmaengine driver
+ * @channels: array of channels which are passed to the driver
+ * @num_channels: number of channels in the array
+ *
+ * This structure is passed to the DMA engine driver via platform data. For
+ * M2P channels, contract is that even channels are for TX and odd for RX.
+ * There is no requirement for the M2M channels.
+ */
+struct ep93xx_dma_platform_data {
+	struct ep93xx_dma_chan_data	*channels;
+	size_t				num_channels;
+};
+
+static inline bool ep93xx_dma_chan_is_m2p(struct dma_chan *chan)
+{
+	return !strcmp(dev_name(chan->device->dev), "ep93xx-dma-m2p");
+}
+
+/**
+ * ep93xx_dma_chan_direction - returns direction the channel can be used
+ * @chan: channel
+ *
+ * This function can be used in filter functions to find out whether the
+ * channel supports given DMA direction. Only M2P channels have such
+ * limitation, for M2M channels the direction is configurable.
+ */
+static inline enum dma_data_direction
+ep93xx_dma_chan_direction(struct dma_chan *chan)
+{
+	if (!ep93xx_dma_chan_is_m2p(chan))
+		return DMA_NONE;
+
+	/* even channels are for TX, odd for RX */
+	return (chan->chan_id % 2 == 0) ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
+}
+
 #endif /* __ASM_ARCH_DMA_H */

drivers/dma/Kconfig

@@ -237,6 +237,13 @@ config MXS_DMA
 	  Support the MXS DMA engine. This engine including APBH-DMA
 	  and APBX-DMA is integrated into Freescale i.MX23/28 chips.
 
+config EP93XX_DMA
+	bool "Cirrus Logic EP93xx DMA support"
+	depends on ARCH_EP93XX
+	select DMA_ENGINE
+	help
+	  Enable support for the Cirrus Logic EP93xx M2P/M2M DMA controller.
+
 config DMA_ENGINE
 	bool
 

drivers/dma/Makefile

@@ -25,3 +25,4 @@ obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o
 obj-$(CONFIG_PL330_DMA) += pl330.o
 obj-$(CONFIG_PCH_DMA) += pch_dma.o
 obj-$(CONFIG_AMBA_PL08X) += amba-pl08x.o
+obj-$(CONFIG_EP93XX_DMA) += ep93xx_dma.o