arch/powerpc/sysdev/bestcomm/bestcomm.h

   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__ */