src/include/gpxe/bitbash.h

   1 #ifndef _GPXE_BITBASH_H
   2 #define _GPXE_BITBASH_H
   3
   4 /** @file
   5  *
   6  * Bit-bashing interfaces
   7  *
   8  */
   9
  10 FILE_LICENCE ( GPL2_OR_LATER );
  11
  12 struct bit_basher;
  13
  14 /** Bit-bashing operations */
  15 struct bit_basher_operations {
  16         /**
  17          * Set/clear output bit
  18          *
  19          * @v basher            Bit-bashing interface
  20          * @v bit_id            Bit number
  21          * @v data              Value to write
  22          *
  23          * @c data will be 0 if a logic 0 should be written (i.e. the
  24          * bit should be cleared), or -1UL if a logic 1 should be
  25          * written (i.e. the bit should be set).  This is done so that
  26          * the method may simply binary-AND @c data with the
  27          * appropriate bit mask.
  28          */
  29         void ( * write ) ( struct bit_basher *basher, unsigned int bit_id,
  30                            unsigned long data );
  31         /**
  32          * Read input bit
  33          *
  34          * @v basher            Bit-bashing interface
  35          * @v bit_id            Bit number
  36          * @ret zero            Input is a logic 0
  37          * @ret non-zero        Input is a logic 1
  38          */
  39         int ( * read ) ( struct bit_basher *basher, unsigned int bit_id );
  40 };
  41
  42 /** A bit-bashing interface */
  43 struct bit_basher {
  44         /** Bit-bashing operations */
  45         struct bit_basher_operations *op;
  46 };
  47
  48 extern void write_bit ( struct bit_basher *basher, unsigned int bit_id,
  49                         unsigned long data );
  50 extern int read_bit ( struct bit_basher *basher, unsigned int bit_id );
  51
  52 #endif /* _GPXE_BITBASH_H */