tree 6ecae23ae25f89edce3ec7b6d620e7027635f67c
parent 8f3d9f354286745c751374f5f1fcafee6b3f3136
author Xu Yilun <yilun.xu@intel.com> 1574054441 +0800
committer Moritz Fischer <mdf@kernel.org> 1588217827 -0700

fpga: dfl: support multiple opens on feature device node.

Each DFL functional block, e.g. AFU (Accelerated Function Unit) and FME
(FPGA Management Engine), could implement more than one function within
its region, but current driver only allows one user application to access
it by exclusive open on device node. So this is not convenient and
flexible for userspace applications, as they have to combine lots of
different functions into one single application.

This patch removes the limitation here to allow multiple opens to each
feature device node for AFU and FME from userspace applications. If user
still needs exclusive access to these device node, O_EXCL flag must be
issued together with open.

Signed-off-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>