usb/musb-new/musb_dma.h

1 /* SPDX-License-Identifier: GPL-2.0 */
3  * MUSB OTG driver DMA controller abstraction
6  * Copyright (C) 2005-2006 by Texas Instruments
7  * Copyright (C) 2006-2007 Nokia Corporation
16  * DMA Controller Abstraction
18  * DMA Controllers are abstracted to allow use of a variety of different
19  * implementations of DMA, as allowed by the Inventra USB cores.  On the
20  * host side, usbcore sets up the DMA mappings and flushes caches; on the
21  * peripheral side, the gadget controller driver does.  Responsibilities
22  * of a DMA controller driver include:
24  *  - Handling the details of moving multiple USB packets
26  *    the correct RX side treatment of short packets and buffer-full
29  *  - Knowing the correlation between dma channels and the
32  *  - Maintaining a list of allocated/available channels.
34  *  - Updating channel status on interrupts,
59  * DMA channel status ... updated by the dma controller driver whenever that
60  * status changes, and protected by the overall controller spinlock.
69 	/* transaction(s) aborted due to ... dma or memory bus error */
78  * struct dma_channel - A DMA channel.
79  * @private_data: channel-private data
81  *	transaction (typically representing many USB maximum-sized packets)
99  * dma_channel_status - return status of dma channel
109 	return (is_dma_capable() && c) ? c->status : MUSB_DMA_STATUS_UNKNOWN;  in dma_channel_status()
113  * struct dma_controller - A DMA Controller.
114  * @start: call this to start a DMA controller;
116  * @stop: call this to stop a DMA controller
118  * @channel_alloc: call this to allocate a DMA channel
119  * @channel_release: call this to release a DMA channel
120  * @channel_abort: call this to abort a pending DMA transaction,
123  * Controllers manage dma channels.