On Fri, Jun 17, 2022 at 04:48:44PM +0300, Ivan Bornyakov wrote: > Document newly introduced fpga_manager_ops callback parse_header() and > flag skip_header along with header_size and data_size fields of struct > fpga_image_info. > > Signed-off-by: Ivan Bornyakov <i.bornyakov@xxxxxxxxxxx> Acked-by: Xu Yilun <yilun.xu@xxxxxxxxx> > --- > Documentation/driver-api/fpga/fpga-mgr.rst | 27 +++++++++++++++++----- > 1 file changed, 21 insertions(+), 6 deletions(-) > > diff --git a/Documentation/driver-api/fpga/fpga-mgr.rst b/Documentation/driver-api/fpga/fpga-mgr.rst > index 42c01f396dce..49c0a9512653 100644 > --- a/Documentation/driver-api/fpga/fpga-mgr.rst > +++ b/Documentation/driver-api/fpga/fpga-mgr.rst > @@ -79,12 +79,27 @@ do the programming sequence for this particular FPGA. These ops return 0 for > success or negative error codes otherwise. > > The programming sequence is:: > - 1. .write_init > - 2. .write or .write_sg (may be called once or multiple times) > - 3. .write_complete > - > -The .write_init function will prepare the FPGA to receive the image data. The > -buffer passed into .write_init will be at most .initial_header_size bytes long; > + 1. .parse_header (optional, may be called once or multiple times) > + 2. .write_init > + 3. .write or .write_sg (may be called once or multiple times) > + 4. .write_complete > + > +The .parse_header function will set header_size and data_size to > +struct fpga_image_info. Before parse_header call, header_size is initialized > +with initial_header_size. If flag skip_header of fpga_manager_ops is true, > +.write function will get image buffer starting at header_size offset from the > +beginning. If data_size is set, .write function will get data_size bytes of > +the image buffer, otherwise .write will get data up to the end of image buffer. > +This will not affect .write_sg, .write_sg will still get whole image in > +sg_table form. If FPGA image is already mapped as a single contiguous buffer, > +whole buffer will be passed into .parse_header. If image is in scatter-gather > +form, core code will buffer up at least .initial_header_size before the first > +call of .parse_header, if it is not enough, .parse_header should set desired > +size into info->header_size and return -EAGAIN, then it will be called again > +with greater part of image buffer on the input. > + > +The .write_init function will prepare the FPGA to receive the image data. The > +buffer passed into .write_init will be at least info->header_size bytes long; > if the whole bitstream is not immediately available then the core code will > buffer up at least this much before starting. > > -- > 2.25.1 >
