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ARM: 6462/1: EP93xx: Document DMA M2P API

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Add kernel-doc documentation for the EP93xx DMA memory to
peripheral/peripheral to memory API.

Signed-off-by: Ryan Mallon <ryan@bluewatersys.com>
Acked-by: Mika Westerberg <mika.westerberg@iki.fi>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Ryan Mallon 2010-10-19 21:14:55 +01:00 committed by Russell King
parent d4c7b1f9b4
commit 85d988fcff
1 changed files with 102 additions and 9 deletions
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111
arch/arm/mach-ep93xx/include/mach/dma.h
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@ -1,5 +1,13 @@
/*
* 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
int ep93xx_dma_m2p_client_register(struct ep93xx_dma_m2p_client *m2p);
/* 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 */