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| author | Xu Yilun <yilun.xu@intel.com> | 2021-03-08 04:59:36 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-03-28 15:58:18 +0300 |
| commit | d72260cc7879c72c186900e7c153007a6137ed8e (patch) | |
| tree | 316d95232beaa8ad34a78df037b764333b089f30 /Documentation/fpga | |
| parent | bbfb54e7b3e484943f8c00c58a0d6549e9078640 (diff) | |
| download | linux-d72260cc7879c72c186900e7c153007a6137ed8e.tar.xz | |
Documentation: fpga: dfl: Add description for DFL UIO support
This patch adds description for UIO support for dfl devices on DFL
bus.
Reviewed-by: Tom Rix <trix@redhat.com>
Reviewed-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/1615168776-8553-3-git-send-email-yilun.xu@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/fpga')
| -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 |