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 struct bcom_bd; /* defined later on ... */
  20
  21
  22 /* ======================================================================== */
  23 /* Generic task management                                                   */
  24 /* ======================================================================== */
  25
  26 /**
  27  * struct bcom_task - Structure describing a loaded BestComm task
  28  *
  29  * This structure is never built by the driver it self. It's built and
  30  * filled the intermediate layer of the BestComm API, the task dependent
  31  * support code.
  32  *
  33  * Most likely you don't need to poke around inside this structure. The
  34  * fields are exposed in the header just for the sake of inline functions
  35  */
  36 struct bcom_task {
  37         unsigned int    tasknum;
  38         unsigned int    flags;
  39         int             irq;
  40
  41         struct bcom_bd  *bd;
  42         phys_addr_t     bd_pa;
  43         void            **cookie;
  44         unsigned short  index;
  45         unsigned short  outdex;
  46         unsigned int    num_bd;
  47         unsigned int    bd_size;
  48
  49         void*           priv;
  50 };
  51
  52 #define BCOM_FLAGS_NONE         0x00000000ul
  53 #define BCOM_FLAGS_ENABLE_TASK  (1ul <<  0)
  54
  55 /**
  56  * bcom_enable - Enable a BestComm task
  57  * @tsk: The BestComm task structure
  58  *
  59  * This function makes sure the given task is enabled and can be run
  60  * by the BestComm engine as needed
  61  */
  62 extern void bcom_enable(struct bcom_task *tsk);
  63
  64 /**
  65  * bcom_disable - Disable a BestComm task
  66  * @tsk: The BestComm task structure
  67  *
  68  * This function disable a given task, making sure it's not executed
  69  * by the BestComm engine.
  70  */
  71 extern void bcom_disable(struct bcom_task *tsk);
  72
  73
  74 /**
  75  * bcom_get_task_irq - Returns the irq number of a BestComm task
  76  * @tsk: The BestComm task structure
  77  */
  78 static inline int
  79 bcom_get_task_irq(struct bcom_task *tsk) {
  80         return tsk->irq;
  81 }
  82
  83 /* ======================================================================== */
  84 /* BD based tasks helpers                                                   */
  85 /* ======================================================================== */
  86
  87 /**
  88  * struct bcom_bd - Structure describing a generic BestComm buffer descriptor
  89  * @status: The current status of this buffer. Exact meaning depends on the
  90  *          task type
  91  * @data: An array of u32 whose meaning depends on the task type.
  92  */
  93 struct bcom_bd {
  94         u32     status;
  95         u32     data[1];        /* variable, but at least 1 */
  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_buffer_done - Checks if a BestComm
 144  * @tsk: The BestComm task structure
 145  */
 146 static inline int
 147 bcom_buffer_done(struct bcom_task *tsk)
 148 {
 149         if (bcom_queue_empty(tsk))
 150                 return 0;
 151         return !(tsk->bd[tsk->outdex].status & BCOM_BD_READY);
 152 }
 153
 154 /**
 155  * bcom_prepare_next_buffer - clear status of next available buffer.
 156  * @tsk: The BestComm task structure
 157  *
 158  * Returns pointer to next buffer descriptor
 159  */
 160 static inline struct bcom_bd *
 161 bcom_prepare_next_buffer(struct bcom_task *tsk)
 162 {
 163         tsk->bd[tsk->index].status = 0; /* cleanup last status */
 164         return &tsk->bd[tsk->index];
 165 }
 166
 167 static inline void
 168 bcom_submit_next_buffer(struct bcom_task *tsk, void *cookie)
 169 {
 170         tsk->cookie[tsk->index] = cookie;
 171         mb();   /* ensure the bd is really up-to-date */
 172         tsk->bd[tsk->index].status |= BCOM_BD_READY;
 173         tsk->index = _bcom_next_index(tsk);
 174         if (tsk->flags & BCOM_FLAGS_ENABLE_TASK)
 175                 bcom_enable(tsk);
 176 }
 177
 178 static inline void *
 179 bcom_retrieve_buffer(struct bcom_task *tsk, u32 *p_status, struct bcom_bd **p_bd)
 180 {
 181         void *cookie = tsk->cookie[tsk->outdex];
 182         if (p_status)
 183                 *p_status = tsk->bd[tsk->outdex].status;
 184         if (p_bd)
 185                 *p_bd = &tsk->bd[tsk->outdex];
 186         tsk->outdex = _bcom_next_outdex(tsk);
 187         return cookie;
 188 }
 189
 190 #endif /* __BESTCOMM_H__ */