1 /*
2 * Public header for the MPC52xx processor BestComm driver
3 *
4 *
5 * Copyright (C) 2006 Sylvain Munaut <tnt@246tNt.com>
6 * Copyright (C) 2005 Varma Electronics Oy,
7 * ( by Andrey Volkov <avolkov@varma-el.com> )
8 * Copyright (C) 2003-2004 MontaVista, Software, Inc.
9 * ( by Dale Farnsworth <dfarnsworth@mvista.com> )
10 *
11 * This file is licensed under the terms of the GNU General Public License
12 * version 2. This program is licensed "as is" without any warranty of any
13 * kind, whether express or implied.
14 */
15
16 #ifndef __BESTCOMM_H__
17 #define __BESTCOMM_H__
18
19 /**
20 * struct bcom_bd - Structure describing a generic BestComm buffer descriptor
21 * @status: The current status of this buffer. Exact meaning depends on the
22 * task type
23 * @data: An array of u32 extra data. Size of array is task dependent.
24 *
25 * Note: Don't dereference a bcom_bd pointer as an array. The size of the
26 * bcom_bd is variable. Use bcom_get_bd() instead.
27 */
28 struct bcom_bd {
29 u32 status;
30 u32 data[0]; /* variable payload size */
31 };
32
33 /* ======================================================================== */
34 /* Generic task management */
35 /* ======================================================================== */
36
37 /**
38 * struct bcom_task - Structure describing a loaded BestComm task
39 *
40 * This structure is never built by the driver it self. It's built and
41 * filled the intermediate layer of the BestComm API, the task dependent
42 * support code.
43 *
44 * Most likely you don't need to poke around inside this structure. The
45 * fields are exposed in the header just for the sake of inline functions
46 */
47 struct bcom_task {
48 unsigned int tasknum;
49 unsigned int flags;
50 int irq;
51
52 struct bcom_bd *bd;
53 phys_addr_t bd_pa;
54 void **cookie;
55 unsigned short index;
56 unsigned short outdex;
57 unsigned int num_bd;
58 unsigned int bd_size;
59
60 void* priv;
61 };
62
63 #define BCOM_FLAGS_NONE 0x00000000ul
64 #define BCOM_FLAGS_ENABLE_TASK (1ul << 0)
65
66 /**
67 * bcom_enable - Enable a BestComm task
68 * @tsk: The BestComm task structure
69 *
70 * This function makes sure the given task is enabled and can be run
71 * by the BestComm engine as needed
72 */
73 extern void bcom_enable(struct bcom_task *tsk);
74
75 /**
76 * bcom_disable - Disable a BestComm task
77 * @tsk: The BestComm task structure
78 *
79 * This function disable a given task, making sure it's not executed
80 * by the BestComm engine.
81 */
82 extern void bcom_disable(struct bcom_task *tsk);
83
84
85 /**
86 * bcom_get_task_irq - Returns the irq number of a BestComm task
87 * @tsk: The BestComm task structure
88 */
89 static inline int
90 bcom_get_task_irq(struct bcom_task *tsk) {
91 return tsk->irq;
92 }
93
94 /* ======================================================================== */
95 /* BD based tasks helpers */
96 /* ======================================================================== */
97
98 #define BCOM_BD_READY 0x40000000ul
99
100 /** _bcom_next_index - Get next input index.
101 * @tsk: pointer to task structure
102 *
103 * Support function; Device drivers should not call this
104 */
105 static inline int
106 _bcom_next_index(struct bcom_task *tsk)
107 {
108 return ((tsk->index + 1) == tsk->num_bd) ? 0 : tsk->index + 1;
109 }
110
111 /** _bcom_next_outdex - Get next output index.
112 * @tsk: pointer to task structure
113 *
114 * Support function; Device drivers should not call this
115 */
116 static inline int
117 _bcom_next_outdex(struct bcom_task *tsk)
118 {
119 return ((tsk->outdex + 1) == tsk->num_bd) ? 0 : tsk->outdex + 1;
120 }
121
122 /**
123 * bcom_queue_empty - Checks if a BestComm task BD queue is empty
124 * @tsk: The BestComm task structure
125 */
126 static inline int
127 bcom_queue_empty(struct bcom_task *tsk)
128 {
129 return tsk->index == tsk->outdex;
130 }
131
132 /**
133 * bcom_queue_full - Checks if a BestComm task BD queue is full
134 * @tsk: The BestComm task structure
135 */
136 static inline int
137 bcom_queue_full(struct bcom_task *tsk)
138 {
139 return tsk->outdex == _bcom_next_index(tsk);
140 }
141
142 /**
143 * bcom_get_bd - Get a BD from the queue
144 * @tsk: The BestComm task structure
145 * index: Index of the BD to fetch
146 */
147 static inline struct bcom_bd
148 *bcom_get_bd(struct bcom_task *tsk, unsigned int index)
149 {
150 /* A cast to (void*) so the address can be incremented by the
151 * real size instead of by sizeof(struct bcom_bd) */
152 return ((void *)tsk->bd) + (index * tsk->bd_size);
153 }
154
155 /**
156 * bcom_buffer_done - Checks if a BestComm
157 * @tsk: The BestComm task structure
158 */
159 static inline int
160 bcom_buffer_done(struct bcom_task *tsk)
161 {
162 struct bcom_bd *bd;
163 if (bcom_queue_empty(tsk))
164 return 0;
165
166 bd = bcom_get_bd(tsk, tsk->outdex);
167 return !(bd->status & BCOM_BD_READY);
168 }
169
170 /**
171 * bcom_prepare_next_buffer - clear status of next available buffer.
172 * @tsk: The BestComm task structure
173 *
174 * Returns pointer to next buffer descriptor
175 */
176 static inline struct bcom_bd *
177 bcom_prepare_next_buffer(struct bcom_task *tsk)
178 {
179 struct bcom_bd *bd;
180
181 bd = bcom_get_bd(tsk, tsk->index);
182 bd->status = 0; /* cleanup last status */
183 return bd;
184 }
185
186 static inline void
187 bcom_submit_next_buffer(struct bcom_task *tsk, void *cookie)
188 {
189 struct bcom_bd *bd = bcom_get_bd(tsk, tsk->index);
190
191 tsk->cookie[tsk->index] = cookie;
192 mb(); /* ensure the bd is really up-to-date */
193 bd->status |= BCOM_BD_READY;
194 tsk->index = _bcom_next_index(tsk);
195 if (tsk->flags & BCOM_FLAGS_ENABLE_TASK)
196 bcom_enable(tsk);
197 }
198
199 static inline void *
200 bcom_retrieve_buffer(struct bcom_task *tsk, u32 *p_status, struct bcom_bd **p_bd)
201 {
202 void *cookie = tsk->cookie[tsk->outdex];
203 struct bcom_bd *bd = bcom_get_bd(tsk, tsk->outdex);
204
205 if (p_status)
206 *p_status = bd->status;
207 if (p_bd)
208 *p_bd = bd;
209 tsk->outdex = _bcom_next_outdex(tsk);
210 return cookie;
211 }
212
213 #endif /* __BESTCOMM_H__ */