diff options
Diffstat (limited to 'Documentation/fpga/dfl.rst')
| -rw-r--r-- | Documentation/fpga/dfl.rst | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/fpga/dfl.rst b/Documentation/fpga/dfl.rst index c41ac76ffaae..f3a1223f2517 100644 --- a/Documentation/fpga/dfl.rst +++ b/Documentation/fpga/dfl.rst @@ -7,6 +7,7 @@ Authors: - Enno Luebbers <enno.luebbers@intel.com> - Xiao Guangrong <guangrong.xiao@linux.intel.com> - Wu Hao <hao.wu@intel.com> +- Xu Yilun <yilun.xu@intel.com> The Device Feature List (DFL) FPGA framework (and drivers according to this framework) hides the very details of low layer hardwares and provides @@ -530,6 +531,31 @@ Being able to specify more than one DFL per BAR has been considered, but it was determined the use case did not provide value. Specifying a single DFL per BAR simplifies the implementation and allows for extra error checking. + +Userspace driver support for DFL devices +======================================== +The purpose of an FPGA is to be reprogrammed with newly developed hardware +components. New hardware can instantiate a new private feature in the DFL, and +then present a DFL device in the system. In some cases users may need a +userspace driver for the DFL device: + +* Users may need to run some diagnostic test for their hardware. +* Users may prototype the kernel driver in user space. +* Some hardware is designed for specific purposes and does not fit into one of + the standard kernel subsystems. + +This requires direct access to MMIO space and interrupt handling from +userspace. The uio_dfl module exposes the UIO device interfaces for this +purpose. + +Currently the uio_dfl driver only supports the Ether Group sub feature, which +has no irq in hardware. So the interrupt handling is not added in this driver. + +UIO_DFL should be selected to enable the uio_dfl module driver. To support a +new DFL feature via UIO direct access, its feature id should be added to the +driver's id_table. + + Open discussion =============== FME driver exports one ioctl (DFL_FPGA_FME_PORT_PR) for partial reconfiguration |