1 /*
2 * MUSB OTG driver DMA controller abstraction
3 *
4 * Copyright 2005 Mentor Graphics Corporation
5 * Copyright (C) 2005-2006 by Texas Instruments
6 * Copyright (C) 2006-2007 Nokia Corporation
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * version 2 as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful, but
13 * WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20 * 02110-1301 USA
21 *
22 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
23 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
24 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
25 * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
28 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
29 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 *
33 */
34
35 #ifndef __MUSB_DMA_H__
36 #define __MUSB_DMA_H__
37
38 struct musb_hw_ep;
39
40 /*
41 * DMA Controller Abstraction
42 *
43 * DMA Controllers are abstracted to allow use of a variety of different
44 * implementations of DMA, as allowed by the Inventra USB cores. On the
45 * host side, usbcore sets up the DMA mappings and flushes caches; on the
46 * peripheral side, the gadget controller driver does. Responsibilities
47 * of a DMA controller driver include:
48 *
49 * - Handling the details of moving multiple USB packets
50 * in cooperation with the Inventra USB core, including especially
51 * the correct RX side treatment of short packets and buffer-full
52 * states (both of which terminate transfers).
53 *
54 * - Knowing the correlation between dma channels and the
55 * Inventra core's local endpoint resources and data direction.
56 *
57 * - Maintaining a list of allocated/available channels.
58 *
59 * - Updating channel status on interrupts,
60 * whether shared with the Inventra core or separate.
61 */
62
63 #define DMA_ADDR_INVALID (~(dma_addr_t)0)
64
65 #ifndef CONFIG_MUSB_PIO_ONLY
66 #define is_dma_capable() (1)
67 #else
68 #define is_dma_capable() (0)
69 #endif
70
71 #ifdef CONFIG_USB_TI_CPPI_DMA
72 #define is_cppi_enabled() 1
73 #else
74 #define is_cppi_enabled() 0
75 #endif
76
77 #ifdef CONFIG_USB_TUSB_OMAP_DMA
78 #define tusb_dma_omap() 1
79 #else
80 #define tusb_dma_omap() 0
81 #endif
82
83 /*
84 * DMA channel status ... updated by the dma controller driver whenever that
85 * status changes, and protected by the overall controller spinlock.
86 */
87 enum dma_channel_status {
88 /* unallocated */
89 MUSB_DMA_STATUS_UNKNOWN,
90 /* allocated ... but not busy, no errors */
91 MUSB_DMA_STATUS_FREE,
92 /* busy ... transactions are active */
93 MUSB_DMA_STATUS_BUSY,
94 /* transaction(s) aborted due to ... dma or memory bus error */
95 MUSB_DMA_STATUS_BUS_ABORT,
96 /* transaction(s) aborted due to ... core error or USB fault */
97 MUSB_DMA_STATUS_CORE_ABORT
98 };
99
100 struct dma_controller;
101
102 /**
103 * struct dma_channel - A DMA channel.
104 * @private_data: channel-private data
105 * @max_len: the maximum number of bytes the channel can move in one
106 * transaction (typically representing many USB maximum-sized packets)
107 * @actual_len: how many bytes have been transferred
108 * @status: current channel status (updated e.g. on interrupt)
109 * @desired_mode: true if mode 1 is desired; false if mode 0 is desired
110 *
111 * channels are associated with an endpoint for the duration of at least
112 * one usb transfer.
113 */
114 struct dma_channel {
115 void *private_data;
116 /* FIXME not void* private_data, but a dma_controller * */
117 size_t max_len;
118 size_t actual_len;
119 enum dma_channel_status status;
120 bool desired_mode;
121 };
122
123 /*
124 * dma_channel_status - return status of dma channel
125 * @c: the channel
126 *
127 * Returns the software's view of the channel status. If that status is BUSY
128 * then it's possible that the hardware has completed (or aborted) a transfer,
129 * so the driver needs to update that status.
130 */
131 static inline enum dma_channel_status
132 dma_channel_status(struct dma_channel *c)
133 {
134 return (is_dma_capable() && c) ? c->status : MUSB_DMA_STATUS_UNKNOWN;
135 }
136
137 /**
138 * struct dma_controller - A DMA Controller.
139 * @start: call this to start a DMA controller;
140 * return 0 on success, else negative errno
141 * @stop: call this to stop a DMA controller
142 * return 0 on success, else negative errno
143 * @channel_alloc: call this to allocate a DMA channel
144 * @channel_release: call this to release a DMA channel
145 * @channel_abort: call this to abort a pending DMA transaction,
146 * returning it to FREE (but allocated) state
147 *
148 * Controllers manage dma channels.
149 */
150 struct dma_controller {
151 int (*start)(struct dma_controller *);
152 int (*stop)(struct dma_controller *);
153 struct dma_channel *(*channel_alloc)(struct dma_controller *,
154 struct musb_hw_ep *, u8 is_tx);
155 void (*channel_release)(struct dma_channel *);
156 int (*channel_program)(struct dma_channel *channel,
157 u16 maxpacket, u8 mode,
158 dma_addr_t dma_addr,
159 u32 length);
160 int (*channel_abort)(struct dma_channel *);
161 };
162
163 /* called after channel_program(), may indicate a fault */
164 extern void musb_dma_completion(struct musb *musb, u8 epnum, u8 transmit);
165
166
167 extern struct dma_controller *__init
168 dma_controller_create(struct musb *, void __iomem *);
169
170 extern void dma_controller_destroy(struct dma_controller *);
171
172 #endif /* __MUSB_DMA_H__ */
173
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