- 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
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