diff options
Diffstat (limited to 'Documentation/driver-api/fpga/fpga-mgr.rst')
| -rw-r--r-- | Documentation/driver-api/fpga/fpga-mgr.rst | 27 |
1 files 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. |