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. --- 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 +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 -- 2.7.4
