On Thu, Apr 11, 2024 at 02:16:24PM +1000, David Gideon wrote:
> Hi Everyone,
>
> Our Xilinx FPGA driver (zynq-fpga.c) is no longer compatible with
> fpga-mgr.c and barfs with:
>
> "Invalid bitstream, could not find a sync word. Bitstream must
> be a byte swapped .bin file"
>
> It seems to come from here (inside fpga_mgr_write_init_buf()):
> size_t header_size = info->header_size;
>
> It uses header_size to decide whether or not to call
> fpga_mgr_write_init() with a NULL buffer and a 0 size, or use a real
> buffer and real size, like this:
>
> if (header_size > count)
> ret = -EINVAL;
> else if (!header_size)
> ret = fpga_mgr_write_init(mgr, info, NULL, 0);
> else
> ret = fpga_mgr_write_init(mgr, info, buf, count);
>
> The trouble is, that if I follow my code path, info->header_size isn't
> set by anyone. So it's **ALWAYS** zero. But the value **should** be
>From your link below, I see info->header_size is set here:
@@ -404,6 +571,8 @@ static int fpga_mgr_firmware_load(struct fpga_manager *mgr,
*/
int fpga_mgr_load(struct fpga_manager *mgr, struct fpga_image_info *info)
{
+ info->header_size = mgr->mops->initial_header_size;
+
if (info->sgt)
return fpga_mgr_buf_load_sg(mgr, info, info->sgt);
Thanks,
Yilun
> 128:
>
> static const struct fpga_manager_ops zynq_fpga_ops = {
> .initial_header_size = 128,
> ...
> };
>
> The issue seems to have been introduced as part of commit 3cc624beba
> which I have linked to here:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/fpga/fpga-mgr.c?id=3cc624beba6310a8a534fb00841f22445a200d54
>
>
> What I find really interesting is that the original mailing list patch
> submission didn't have this bug, and would have worked for us:
>
> + if (info->header_size)
> + header_size = info->header_size;
> + else
> + header_size = mgr->mops->initial_header_size;
>
> Could this be a viable way to ensure that the FPGA manager driver is
> compatible with the zynq-fpga.c driver again?
>
>
> - DG
>
