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Annotation of coherent/f/usr/man/KERNEL/dmareq, revision 1.1.1.1

1.1       root        1: ddmmaarreeqq() -- Accessible Kernel Routine
                      2: 
                      3: #iinncclluuddee <ssyyss/bbuuff.hh>
                      4: vvooiidd
                      5: ddmmaarreeqq(_b_p, _i_o_p, _d_e_v, _r_e_q)
                      6: BBUUFF *_b_p;
                      7: IIOO *_i_o_p;
                      8: ddeevv_tt _d_e_v;
                      9: iinntt _r_e_q;
                     10: 
                     11: ddmmaarreeqq(), like iioorreeqq(), queues an  I/O request through the block routine of
                     12: a device driver.   _b_p points to the BBUUFF structure  for the I/O.  _i_o_p points
                     13: to an  IIOO structure.  _d_e_v is  the device to access.   Finally, _r_e_q requests
                     14: the type of I/O: it must be either BBRREEAADD or BBWWRRIITTEE.
                     15: 
                     16: ddmmaarreeqq() converts  I/O requests  that straddle  DMA boundaries into  two or
                     17: three non-straddling  requests.  It converts  block DMA straddles  into two
                     18: non-straddling  I/O requests;  it converts other  DMA straddles  into three
                     19: non-straddling  I/O requests,  where  the DMA-straddling  block is  handled
                     20: through the  buffer cache.   Note that the  driver's block routine  must be
                     21: able to function with the smaller I/O requests.
                     22: 
                     23: _S_e_e _A_l_s_o
                     24: aacccceessssiibbllee kkeerrnneell rroouuttiinneess, iioorreeqq()

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