ARM: 6462/1: EP93xx: Document DMA M2P API (85d988fc) · Commits · e / devices / android_kernel_xiaomi_markw

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

+102 −9

Original line number	Diff line number	Diff line
		/*
		* arch/arm/mach-ep93xx/include/mach/dma.h
		/**
		* DOC: EP93xx DMA M2P memory to peripheral and peripheral to memory engine
		*
		* The EP93xx DMA M2P subsystem handles DMA transfers between memory and
		* peripherals. DMA M2P channels are available for audio, UARTs and IrDA.
		* See chapter 10 of the EP93xx users guide for full details on the DMA M2P
		* engine.
		*
		* See sound/soc/ep93xx/ep93xx-pcm.c for an example use of the DMA M2P code.
		*
		*/

		#ifndef __ASM_ARCH_DMA_H
		@@ -8,12 +16,34 @@
		#include <linux/list.h>
		#include <linux/types.h>

		/**
		* struct ep93xx_dma_buffer - Information about a buffer to be transferred
		* using the DMA M2P engine
		*
		* @list: Entry in DMA buffer list
		* @bus_addr: Physical address of the buffer
		* @size: Size of the buffer in bytes
		*/
		struct ep93xx_dma_buffer {
		struct list_head list;
		u32 bus_addr;
		u16 size;
		};

		/**
		* struct ep93xx_dma_m2p_client - Information about a DMA M2P client
		*
		* @name: Unique name for this client
		* @flags: Client flags
		* @cookie: User data to pass to callback functions
		* @buffer_started: Non NULL function to call when a transfer is started.
		* The arguments are the user data cookie and the DMA
		* buffer which is starting.
		* @buffer_finished: Non NULL function to call when a transfer is completed.
		* The arguments are the user data cookie, the DMA buffer
		* which has completed, and a boolean flag indicating if
		* the transfer had an error.
		*/
		struct ep93xx_dma_m2p_client {
		char *name;
		u8 flags;
		@@ -24,10 +54,11 @@ struct ep93xx_dma_m2p_client {
		struct ep93xx_dma_buffer *buf,
		int bytes, int error);

		/* Internal to the DMA code. */
		/* private: Internal use only */
		void *channel;
		};

		/* DMA M2P ports */
		#define EP93XX_DMA_M2P_PORT_I2S1 0x00
		#define EP93XX_DMA_M2P_PORT_I2S2 0x01
		#define EP93XX_DMA_M2P_PORT_AAC1 0x02
		@@ -39,18 +70,80 @@ struct ep93xx_dma_m2p_client {
		#define EP93XX_DMA_M2P_PORT_UART3 0x08
		#define EP93XX_DMA_M2P_PORT_IRDA 0x09
		#define EP93XX_DMA_M2P_PORT_MASK 0x0f
		#define EP93XX_DMA_M2P_TX 0x00
		#define EP93XX_DMA_M2P_RX 0x10
		#define EP93XX_DMA_M2P_ABORT_ON_ERROR 0x20
		#define EP93XX_DMA_M2P_IGNORE_ERROR 0x40
		#define EP93XX_DMA_M2P_ERROR_MASK 0x60

		/* DMA M2P client flags */
		#define EP93XX_DMA_M2P_TX 0x00 /* Memory to peripheral */
		#define EP93XX_DMA_M2P_RX 0x10 /* Peripheral to memory */

		/*
		* DMA M2P client error handling flags. See the EP93xx users guide
		* documentation on the DMA M2P CONTROL register for more details
		*/
		#define EP93XX_DMA_M2P_ABORT_ON_ERROR 0x20 /* Abort on peripheral error */
		#define EP93XX_DMA_M2P_IGNORE_ERROR 0x40 /* Ignore peripheral errors */
		#define EP93XX_DMA_M2P_ERROR_MASK 0x60 /* Mask of error bits */

		/**
		* ep93xx_dma_m2p_client_register - Register a client with the DMA M2P
		* subsystem
		*
		* @m2p: Client information to register
		* returns 0 on success
		*
		* The DMA M2P subsystem allocates a channel and an interrupt line for the DMA
		* client
		*/
		int ep93xx_dma_m2p_client_register(struct ep93xx_dma_m2p_client *m2p);

		/**
		* ep93xx_dma_m2p_client_unregister - Unregister a client from the DMA M2P
		* subsystem
		*
		* @m2p: Client to unregister
		*
		* Any transfers currently in progress will be completed in hardware, but
		* ignored in software.
		*/
		void ep93xx_dma_m2p_client_unregister(struct ep93xx_dma_m2p_client *m2p);

		/**
		* ep93xx_dma_m2p_submit - Submit a DMA M2P transfer
		*
		* @m2p: DMA Client to submit the transfer on
		* @buf: DMA Buffer to submit
		*
		* If the current or next transfer positions are free on the M2P client then
		* the transfer is started immediately. If not, the transfer is added to the
		* list of pending transfers. This function must not be called from the
		* buffer_finished callback for an M2P channel.
		*
		*/
		void ep93xx_dma_m2p_submit(struct ep93xx_dma_m2p_client *m2p,
		struct ep93xx_dma_buffer *buf);

		/**
		* ep93xx_dma_m2p_submit_recursive - Put a DMA transfer on the pending list
		* for an M2P channel
		*
		* @m2p: DMA Client to submit the transfer on
		* @buf: DMA Buffer to submit
		*
		* This function must only be called from the buffer_finished callback for an
		* M2P channel. It is commonly used to add the next transfer in a chained list
		* of DMA transfers.
		*/
		void ep93xx_dma_m2p_submit_recursive(struct ep93xx_dma_m2p_client *m2p,
		struct ep93xx_dma_buffer *buf);

		/**
		* ep93xx_dma_m2p_flush - Flush all pending transfers on a DMA M2P client
		*
		* @m2p: DMA client to flush transfers on
		*
		* Any transfers currently in progress will be completed in hardware, but
		* ignored in software.
		*
		*/
		void ep93xx_dma_m2p_flush(struct ep93xx_dma_m2p_client *m2p);

		#endif /* __ASM_ARCH_DMA_H */