On Thu, Jul 13, 2017 at 12:25:20PM +0800, Wu Hao wrote: > On Wed, Jul 12, 2017 at 09:51:32AM -0500, Alan Tull wrote: > > On Sun, Jun 25, 2017 at 8:51 PM, Wu Hao <hao.wu@xxxxxxxxx> wrote: > > > > Hi Hao, > > > > > Add a document for Intel FPGA driver overview. > > > > > > Signed-off-by: Enno Luebbers <enno.luebbers@xxxxxxxxx> > > > Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> > > > Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx> > > > ---- > > > v2: added FME fpga-mgr/bridge/region platform driver to driver organization. > > > updated open discussion per current implementation. > > > fixed some typos. > > > --- > > > Documentation/fpga/intel-fpga.txt | 256 ++++++++++++++++++++++++++++++++++++++ > > > 1 file changed, 256 insertions(+) > > > create mode 100644 Documentation/fpga/intel-fpga.txt > > > > > > diff --git a/Documentation/fpga/intel-fpga.txt b/Documentation/fpga/intel-fpga.txt > > > new file mode 100644 > > > index 0000000..4a29470 > > > --- /dev/null > > > +++ b/Documentation/fpga/intel-fpga.txt > > > @@ -0,0 +1,256 @@ > > > +=============================================================================== > > > + Intel FPGA driver Overview > > > +------------------------------------------------------------------------------- > > > + Enno Luebbers <enno.luebbers@xxxxxxxxx> > > > + Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx> > > > + Wu Hao <hao.wu@xxxxxxxxx> > > > + > > > +The Intel FPGA driver provides interfaces for userspace applications to > > > +configure, enumerate, open, and access FPGA accelerators on platforms equipped > > > +with Intel(R) FPGA PCIe based solutions and enables system level management > > > +functions such as FPGA reconfiguration, power management, and virtualization. > > > + > > > +HW Architecture > > > +=============== > > > +From the OS's point of view, the FPGA hardware appears as a regular PCIe device. > > > +The FPGA device memory is organized using a predefined data structure (Device > > > +Feature List). Features supported by the particular FPGA device are exposed > > > +through these data structures, as illustrated below: > > > + > > > + +-------------------------------+ +-------------+ > > > + | PF | | VF | > > > + +-------------------------------+ +-------------+ > > > + ^ ^ ^ ^ > > > + | | | | > > > ++-----|------------|---------|--------------|-------+ > > > +| | | | | | > > > +| +-----+ +-------+ +-------+ +-------+ | > > > +| | FME | | Port0 | | Port1 | | Port2 | | > > > +| +-----+ +-------+ +-------+ +-------+ | > > > +| ^ ^ ^ | > > > +| | | | | > > > +| +-------+ +------+ +-------+ | > > > +| | AFU | | AFU | | AFU | | > > > +| +-------+ +------+ +-------+ | > > > +| | > > > +| FPGA PCIe Device | > > > ++---------------------------------------------------+ > > > + > > > +The driver supports PCIe SR-IOV to create virtual functions (VFs) which can be > > > +used to assign individual accelerators to virtual machines. > > > + > > > +FME (FPGA Management Engine) > > > +============================ > > > +The FPGA Management Engine performs power and thermal management, error > > > +reporting, reconfiguration, performance reporting, and other infrastructure > > > +functions. Each FPGA has one FME, which is always accessed through the physical > > > +function (PF). > > > + > > > +User-space applications can acquire exclusive access to the FME using open(), > > > +and release it using close(). > > > + > > > +The following functions are exposed through ioctls: > > > + > > > + Get driver API version (FPGA_GET_API_VERSION) > > > + Check for extensions (FPGA_CHECK_EXTENSION) > > > + Assign port to PF (FPGA_FME_PORT_ASSIGN) > > > + Release port from PF (FPGA_FME_PORT_RELEASE) > > > + Program bitstream (FPGA_FME_PORT_PR) > > > + > > > > I was hoping the API mailing list might have an opinion about this, > > but I think adding ioctls to the kernel is discouraged. Could these > > be sysfs? > > Hi Alan, > > As you see below, we have defined a lot of sysfs interface for device > info, attributes and simple control operations. But for some actions > which requires complex inputs/outputs parameters (e.g a struct with > multiple items) with userspace, ioctls are used. I feel in such cases, > ioctls seem more suitable than sysfs. > Also, we're thinking that some operations require that you first "acquire ownership" of the respective device, which I believe maps more easily to open() and ioctls than sysfs. Thanks - Enno -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
