The default functions phys_to_dma, dma_to_phys implement identity
mapping as fast inline functions.  Some systems, however, may need a
custom function to implement its own mapping between CPU addresses and
device addresses. This new configuration option allows the functions
to be external when needed (such as for the ConneXt device)
Signed-off-by: NAlessandro Rubini <rubini@gnudd.com>
Link: http://lkml.kernel.org/r/6e4329b772df675f1c442f68e59e844e4dd8c965.1333560789.git.rubini@gnudd.comAcked-by: NGiancarlo Asnaghi <giancarlo.asnaghi@st.com>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>