On 1/1/21 7:13 PM, Xu Yilun wrote: > This patch adds description for UIO support for dfl devices on DFL > bus. > > Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx> > --- > v2: no doc in v1, add it for v2. > v3: some documentation fixes. > v4: documentation change since the driver matching is changed. > v5: no change. > --- > Documentation/fpga/dfl.rst | 24 ++++++++++++++++++++++++ > 1 file changed, 24 insertions(+) > > diff --git a/Documentation/fpga/dfl.rst b/Documentation/fpga/dfl.rst > index 0404fe6..b8497f3 100644 > --- a/Documentation/fpga/dfl.rst > +++ b/Documentation/fpga/dfl.rst > @@ -7,6 +7,7 @@ Authors: > - Enno Luebbers <enno.luebbers@xxxxxxxxx> > - Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> > - Wu Hao <hao.wu@xxxxxxxxx> > +- Xu Yilun <yilun.xu@xxxxxxxxx> > > The Device Feature List (DFL) FPGA framework (and drivers according to > this framework) hides the very details of low layer hardwares and provides > @@ -502,6 +503,29 @@ FME Partial Reconfiguration Sub Feature driver (see drivers/fpga/dfl-fme-pr.c) > could be a reference. > > > +UIO 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 get a DFL device in their system. In some cases users may need a userspace > +driver for the DFL device: > + > +* Users may need to run some diagnostic test for their hardwares. > +* 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 the direct access to the MMIO space and interrupt handling in This may be better stated as: "This requires direct access to MMIO space and interrupt handling from userspace." - Russ > +userspace. The dfl-uio-pdev module exposes the UIO device interfaces for this > +purpose. It adds the uio_pdrv_genirq platform device with the resources of > +the DFL feature, and lets the generic UIO platform device driver provide UIO > +support to userspace. > + > +FPGA_DFL_UIO_PDEV should be selected to enable the dfl-uio-pdev module driver. > +To support a new DFL feature been directly accessed via UIO, 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
