diff options
Diffstat (limited to 'arch/arm/mach-ep93xx')
| -rw-r--r-- | arch/arm/mach-ep93xx/include/mach/dma.h | 111 |
1 files changed, 102 insertions, 9 deletions
diff --git a/arch/arm/mach-ep93xx/include/mach/dma.h b/arch/arm/mach-ep93xx/include/mach/dma.h index 3a5961d..5e31b2b 100644 --- a/arch/arm/mach-ep93xx/include/mach/dma.h +++ b/arch/arm/mach-ep93xx/include/mach/dma.h @@ -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 */ |