Merge tag 'fpga-late-for-5.20-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/fpga/linux-fpga into char-misc-next

Xu writes:

Here is the second set of FPGA changes for 5.20-rc1

FPGA Manager core:
- Ivan's change to support image offset and data size setting for
reprograming. A parse_header() callback is introduced for drivers to
specify these info.
- Colin's immediate spelling fix for Ivan's patch.

Microchip:
- Ivan's change to add Microchip MPF FPGA manager driver. And MAINTAINERS
entry added for the driver.

All patches have been reviewed on the mailing list, and have been in the
last linux-next releases (as part of our for-next branch).

Signed-off-by: Xu Yilun <yilun.xu@intel.com>

* tag 'fpga-late-for-5.20-rc1' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/fpga/linux-fpga:
  fpga: fpga-mgr: Fix spelling mistake "bitsream" -> "bitstream"
  MAINTAINERS: add Microchip PolarFire FPGA drivers entry
  dt-bindings: fpga: add binding doc for microchip-spi fpga mgr
  fpga: microchip-spi: add Microchip MPF FPGA manager
  docs: fpga: mgr: document parse_header() callback
  fpga: fpga-mgr: support bitstream offset in image buffer

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.