Hi Greg, On Sat, Feb 27, 2021 at 04:42:55PM +0100, Greg KH wrote: > On Sat, Feb 27, 2021 at 11:27:03PM +0800, Xu Yilun wrote: > > This patch supports the DFL drivers be written in userspace. This is > > realized by exposing the userspace I/O device interfaces. > > > > The driver now only binds the ether group feature, which has no irq. So > > the irq support is not implemented yet. > > > > Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx> > > Reviewed-by: Tom Rix <trix@xxxxxxxxxx> > > --- > > v9: switch to add a uio driver in drivers/uio > > v10: add the source file in MAINTAINERS > > more descriptive Kconfig header > > add detailed path for opae uio example > > v11: no change > > --- > > MAINTAINERS | 1 + > > drivers/uio/Kconfig | 17 +++++++++++++ > > drivers/uio/Makefile | 1 + > > drivers/uio/uio_dfl.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++ > > 4 files changed, 85 insertions(+) > > create mode 100644 drivers/uio/uio_dfl.c > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > index 000fe0b..4dc0354 100644 > > --- a/MAINTAINERS > > +++ b/MAINTAINERS > > @@ -6943,6 +6943,7 @@ S: Maintained > > F: Documentation/ABI/testing/sysfs-bus-dfl* > > F: Documentation/fpga/dfl.rst > > F: drivers/fpga/dfl* > > +F: drivers/uio/uio_dfl.c > > F: include/linux/dfl.h > > F: include/uapi/linux/fpga-dfl.h > > > > diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig > > index 202ee81..5531f3a 100644 > > --- a/drivers/uio/Kconfig > > +++ b/drivers/uio/Kconfig > > @@ -165,4 +165,21 @@ config UIO_HV_GENERIC > > to network and storage devices from userspace. > > > > If you compile this as a module, it will be called uio_hv_generic. > > + > > +config UIO_DFL > > + tristate "Generic driver for DFL (Device Feature List) bus" > > + depends on FPGA_DFL > > + help > > + Generic DFL (Device Feature List) driver for Userspace I/O devices. > > + It is useful to provide direct access to DFL devices from userspace. > > + A sample userspace application using this driver is available for > > + download in a git repository: > > + > > + git clone https://github.com/OPAE/opae-sdk.git > > + > > + It could be found at: > > + > > + opae-sdk/tools/libopaeuio/ > > + > > + If you compile this as a module, it will be called uio_dfl. > > endif > > diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile > > index c285dd2..f2f416a1 100644 > > --- a/drivers/uio/Makefile > > +++ b/drivers/uio/Makefile > > @@ -11,3 +11,4 @@ obj-$(CONFIG_UIO_PRUSS) += uio_pruss.o > > obj-$(CONFIG_UIO_MF624) += uio_mf624.o > > obj-$(CONFIG_UIO_FSL_ELBC_GPCM) += uio_fsl_elbc_gpcm.o > > obj-$(CONFIG_UIO_HV_GENERIC) += uio_hv_generic.o > > +obj-$(CONFIG_UIO_DFL) += uio_dfl.o > > diff --git a/drivers/uio/uio_dfl.c b/drivers/uio/uio_dfl.c > > new file mode 100644 > > index 0000000..89c0fc7 > > --- /dev/null > > +++ b/drivers/uio/uio_dfl.c > > @@ -0,0 +1,66 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +/* > > + * Generic DFL driver for Userspace I/O devicess > > + * > > + * Copyright (C) 2021 Intel Corporation, Inc. > > + */ > > +#include <linux/dfl.h> > > +#include <linux/errno.h> > > +#include <linux/module.h> > > +#include <linux/uio_driver.h> > > + > > +#define DRIVER_NAME "uio_dfl" > > + > > +static int uio_dfl_probe(struct dfl_device *ddev) > > +{ > > + struct resource *r = &ddev->mmio_res; > > + struct device *dev = &ddev->dev; > > + struct uio_info *uioinfo; > > + struct uio_mem *uiomem; > > + int ret; > > + > > + uioinfo = devm_kzalloc(dev, sizeof(struct uio_info), GFP_KERNEL); > > + if (!uioinfo) > > + return -ENOMEM; > > + > > + uioinfo->name = DRIVER_NAME; > > + uioinfo->version = "0"; > > + > > + uiomem = &uioinfo->mem[0]; > > + uiomem->memtype = UIO_MEM_PHYS; > > + uiomem->addr = r->start & PAGE_MASK; > > + uiomem->offs = r->start & ~PAGE_MASK; > > + uiomem->size = (uiomem->offs + resource_size(r) > > + + PAGE_SIZE - 1) & PAGE_MASK; > > + uiomem->name = r->name; > > + > > + /* Irq is yet to be supported */ > > + uioinfo->irq = UIO_IRQ_NONE; > > + > > + ret = devm_uio_register_device(dev, uioinfo); > > + if (ret) > > + dev_err(dev, "unable to register uio device\n"); > > + > > + return ret; > > +} > > + > > +#define FME_FEATURE_ID_ETH_GROUP 0x10 > > Why are you saying that an ethernet driver should be using the UIO > interface? > > And why can't you use the existing UIO drivers that bind to memory > regions specified by firmware? Without an interrupt being used, why is > UIO needed at all? That was an earlier version -- which from your comments you didn't seem to like :) Maybe miscommunication. Essentially I see two options: - Have a DFL bus driver instantiate a platform driver (uio_pdrv_genirq) which I *think* you described above? - What this patch implements -- a UIO driver on the DFL bus These FPGA devices can on the fly change their contents and -- even if just for test -- being able to expose a bunch of registers via UIO can be extremely useful. Whether a device should expose registers or not should be up to the implemeneter of the FPGA design I think (policy). This patch (or the previous version) provides a mechanism to do so via DFL. This is similar in nature to uio_pdrv_genirq on a DT based platform, to expose the registers you instantiate the DT node. Re-implementing a new driver for each of these instances doesn't seem desirable and tying DFL as enumeration mechanism to UIO seems like a good compromise for enabling this kind of functionality. Note this is *not* an attempt to bypass the network stack or other existing subsystems. Cheers, Moritz
