usb/musb-new/musb_dma.h

2  * MUSB OTG driver DMA controller abstraction
5  * Copyright (C) 2005-2006 by Texas Instruments
6  * Copyright (C) 2006-2007 Nokia Corporation
8  * SPDX-License-Identifier:	GPL-2.0
17  * DMA Controller Abstraction
19  * DMA Controllers are abstracted to allow use of a variety of different
20  * implementations of DMA, as allowed by the Inventra USB cores.  On the
21  * host side, usbcore sets up the DMA mappings and flushes caches; on the
22  * peripheral side, the gadget controller driver does.  Responsibilities
23  * of a DMA controller driver include:
25  *  - Handling the details of moving multiple USB packets
27  *    the correct RX side treatment of short packets and buffer-full
30  *  - Knowing the correlation between dma channels and the
33  *  - Maintaining a list of allocated/available channels.
35  *  - Updating channel status on interrupts,
60  * DMA channel status ... updated by the dma controller driver whenever that
61  * status changes, and protected by the overall controller spinlock.
70 	/* transaction(s) aborted due to ... dma or memory bus error */
79  * struct dma_channel - A DMA channel.
80  * @private_data: channel-private data
82  *	transaction (typically representing many USB maximum-sized packets)
100  * dma_channel_status - return status of dma channel
110 	return (is_dma_capable() && c) ? c->status : MUSB_DMA_STATUS_UNKNOWN;  in dma_channel_status()
114  * struct dma_controller - A DMA Controller.
115  * @start: call this to start a DMA controller;
117  * @stop: call this to stop a DMA controller
119  * @channel_alloc: call this to allocate a DMA channel
120  * @channel_release: call this to release a DMA channel
121  * @channel_abort: call this to abort a pending DMA transaction,
124  * Controllers manage dma channels.