2 * MUSB OTG driver DMA controller abstraction
4 * Copyright 2005 Mentor Graphics Corporation
5 * Copyright (C) 2005-2006 by Texas Instruments
6 * Copyright (C) 2006-2007 Nokia Corporation
8 * SPDX-License-Identifier: GPL-2.0
11 #ifndef __MUSB_DMA_H__
12 #define __MUSB_DMA_H__
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
26 * in cooperation with the Inventra USB core, including especially
27 * the correct RX side treatment of short packets and buffer-full
28 * states (both of which terminate transfers).
30 * - Knowing the correlation between dma channels and the
31 * Inventra core's local endpoint resources and data direction.
33 * - Maintaining a list of allocated/available channels.
35 * - Updating channel status on interrupts,
36 * whether shared with the Inventra core or separate.
39 #define DMA_ADDR_INVALID (~(dma_addr_t)0)
41 #ifndef CONFIG_USB_MUSB_PIO_ONLY
42 #define is_dma_capable() (1)
44 #define is_dma_capable() (0)
47 #ifdef CONFIG_USB_TI_CPPI_DMA
48 #define is_cppi_enabled() 1
50 #define is_cppi_enabled() 0
53 #ifdef CONFIG_USB_TUSB_OMAP_DMA
54 #define tusb_dma_omap() 1
56 #define tusb_dma_omap() 0
60 * DMA channel status ... updated by the dma controller driver whenever that
61 * status changes, and protected by the overall controller spinlock.
63 enum dma_channel_status {
65 MUSB_DMA_STATUS_UNKNOWN,
66 /* allocated ... but not busy, no errors */
68 /* busy ... transactions are active */
70 /* transaction(s) aborted due to ... dma or memory bus error */
71 MUSB_DMA_STATUS_BUS_ABORT,
72 /* transaction(s) aborted due to ... core error or USB fault */
73 MUSB_DMA_STATUS_CORE_ABORT
76 struct dma_controller;
79 * struct dma_channel - A DMA channel.
80 * @private_data: channel-private data
81 * @max_len: the maximum number of bytes the channel can move in one
82 * transaction (typically representing many USB maximum-sized packets)
83 * @actual_len: how many bytes have been transferred
84 * @status: current channel status (updated e.g. on interrupt)
85 * @desired_mode: true if mode 1 is desired; false if mode 0 is desired
87 * channels are associated with an endpoint for the duration of at least
92 /* FIXME not void* private_data, but a dma_controller * */
95 enum dma_channel_status status;
100 * dma_channel_status - return status of dma channel
103 * Returns the software's view of the channel status. If that status is BUSY
104 * then it's possible that the hardware has completed (or aborted) a transfer,
105 * so the driver needs to update that status.
107 static inline enum dma_channel_status
108 dma_channel_status(struct dma_channel *c)
110 return (is_dma_capable() && c) ? c->status : MUSB_DMA_STATUS_UNKNOWN;
114 * struct dma_controller - A DMA Controller.
115 * @start: call this to start a DMA controller;
116 * return 0 on success, else negative errno
117 * @stop: call this to stop a DMA controller
118 * return 0 on success, else negative errno
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,
122 * returning it to FREE (but allocated) state
124 * Controllers manage dma channels.
126 struct dma_controller {
127 int (*start)(struct dma_controller *);
128 int (*stop)(struct dma_controller *);
129 struct dma_channel *(*channel_alloc)(struct dma_controller *,
130 struct musb_hw_ep *, u8 is_tx);
131 void (*channel_release)(struct dma_channel *);
132 int (*channel_program)(struct dma_channel *channel,
133 u16 maxpacket, u8 mode,
136 int (*channel_abort)(struct dma_channel *);
137 int (*is_compatible)(struct dma_channel *channel,
139 void *buf, u32 length);
142 /* called after channel_program(), may indicate a fault */
143 extern void musb_dma_completion(struct musb *musb, u8 epnum, u8 transmit);
146 extern struct dma_controller *__init
147 dma_controller_create(struct musb *, void __iomem *);
149 extern void dma_controller_destroy(struct dma_controller *);
151 #endif /* __MUSB_DMA_H__ */