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* [PATCH v10 0/2] UIO support for dfl devices
@ 2021-02-01  5:38 Xu Yilun
  2021-02-01  5:38 ` [PATCH v10 1/2] uio: uio_dfl: add userspace i/o driver for DFL bus Xu Yilun
  2021-02-01  5:38 ` [PATCH v10 2/2] Documentation: fpga: dfl: Add description for DFL UIO support Xu Yilun
  0 siblings, 2 replies; 6+ messages in thread
From: Xu Yilun @ 2021-02-01  5:38 UTC (permalink / raw)
  To: gregkh, mdf, linux-fpga, linux-kernel; +Cc: trix, lgoncalv, yilun.xu, hao.wu

This patchset supports some dfl device drivers written in userspace.

In the patchset v1, the "driver_override" interface should be used to bind
the DFL UIO driver to DFL devices. But there is concern that the 
"driver_override" interface is not OK itself.

In v2, we use a new matching algorithem. The "driver_override" interface
is abandoned, the DFL UIO driver matches any DFL device which could not be
handled by other DFL drivers. So the DFL UIO driver could be used for new 
DFL devices which are not supported by kernel. The concern is the UIO may 
not be suitable as a default/generic driver for all dfl features, such as
features with multiple interrupts.

In v4, we specify each matching device in the id_table of the UIO driver,
just the same as other dfl drivers do. Now the UIO driver supports Ether
Group feature. To support more DFL features, their feature ids should be
added to the driver's id_table.

Before v9, we create a "uio_pdrv_genirq" platform device using DFL devices'
resources. Then we leverage the uio_pdrv_genirq driver for UIO support. It
is suggested that we implement a driver in drivers/uio that directly calls
UIO framework APIs. So we implement the uio_dfl driver in v9. The driver
now only binds the ether group feature, which has no irq. So the irq 
support is not implemented yet.


Main changes from v1: 
- switch to the new matching algorithem. It matches DFL devices which could
  not be handled by other DFL drivers.
- refacor the code about device resources filling.
- add the documentation.

Main changes from v2: 
- split the match ops changes in dfl.c to an independent patch.
- move the declarations needed for dfl-uio-pdev from include/linux/dfl.h
  to driver/fpga/dfl.h
- some minor fixes.

Main changes from v3: 
- switch to specifying each matching device in the driver's id_table.
- refactor the irq handling code.

Main changes from v4: 
- refactor the irq handling code.

Main changes from v5: 
- fix the res[] zero initialization issue.
- improve the return code for probe().
- some doc improvement.

Main changes from v6: 
- use platform_device_register_resndata() for pdev creation.

Main changes from v7: 
- some doc fixes.

Main changes from v8:
- switch to add a uio driver in drivers/uio

Main changes from v9:
- add this source file in MAINTAINERS
- improve the Kconfig, add more descriptive Kconfig header, add detailed
  path for opae uio example in Kconfig.


Xu Yilun (2):
  uio: uio_dfl: add userspace i/o driver for DFL bus
  Documentation: fpga: dfl: Add description for DFL UIO support

 Documentation/fpga/dfl.rst | 23 ++++++++++++++++
 MAINTAINERS                |  1 +
 drivers/uio/Kconfig        | 17 ++++++++++++
 drivers/uio/Makefile       |  1 +
 drivers/uio/uio_dfl.c      | 66 ++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 108 insertions(+)
 create mode 100644 drivers/uio/uio_dfl.c

-- 
2.7.4


^ permalink raw reply	[flat|nested] 6+ messages in thread
* [PATCH v10 1/2] uio: uio_dfl: add userspace i/o driver for DFL bus
  2021-02-01  5:38 [PATCH v10 0/2] UIO support for dfl devices Xu Yilun
@ 2021-02-01  5:38 ` Xu Yilun
  2021-02-01 14:12   ` Tom Rix
  2021-02-01  5:38 ` [PATCH v10 2/2] Documentation: fpga: dfl: Add description for DFL UIO support Xu Yilun
  1 sibling, 1 reply; 6+ messages in thread
From: Xu Yilun @ 2021-02-01  5:38 UTC (permalink / raw)
  To: gregkh, mdf, linux-fpga, linux-kernel; +Cc: trix, lgoncalv, yilun.xu, hao.wu

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@intel.com>
---
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
---
 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 147d1d9..4d01a21 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
+
+static const struct dfl_device_id uio_dfl_ids[] = {
+	{ FME_ID, FME_FEATURE_ID_ETH_GROUP },
+	{ }
+};
+MODULE_DEVICE_TABLE(dfl, uio_dfl_ids);
+
+static struct dfl_driver uio_dfl_driver = {
+	.drv = {
+		.name = DRIVER_NAME,
+	},
+	.id_table	= uio_dfl_ids,
+	.probe		= uio_dfl_probe,
+};
+module_dfl_driver(uio_dfl_driver);
+
+MODULE_DESCRIPTION("Generic DFL driver for Userspace I/O devices");
+MODULE_AUTHOR("Intel Corporation");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* [PATCH v10 2/2] Documentation: fpga: dfl: Add description for DFL UIO support
  2021-02-01  5:38 [PATCH v10 0/2] UIO support for dfl devices Xu Yilun
  2021-02-01  5:38 ` [PATCH v10 1/2] uio: uio_dfl: add userspace i/o driver for DFL bus Xu Yilun
@ 2021-02-01  5:38 ` Xu Yilun
  2021-02-01 12:59   ` Wu, Hao
  1 sibling, 1 reply; 6+ messages in thread
From: Xu Yilun @ 2021-02-01  5:38 UTC (permalink / raw)
  To: gregkh, mdf, linux-fpga, linux-kernel; +Cc: trix, lgoncalv, yilun.xu, hao.wu

This patch adds description for UIO support for dfl devices on DFL
bus.

Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Reviewed-by: Tom Rix <trix@redhat.com>
---
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.
v6: improve the title of the userspace driver support section.
    some word improvement.
v7: rebased to next-20210119
v8: some doc fixes.
v9: some doc change since we switch to the driver in drivers/uio.
v10: no change.
---
 Documentation/fpga/dfl.rst | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/Documentation/fpga/dfl.rst b/Documentation/fpga/dfl.rst
index c41ac76..e35cf87 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 +531,28 @@ 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.
+
+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
-- 
2.7.4


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* RE: [PATCH v10 2/2] Documentation: fpga: dfl: Add description for DFL UIO support
  2021-02-01  5:38 ` [PATCH v10 2/2] Documentation: fpga: dfl: Add description for DFL UIO support Xu Yilun
@ 2021-02-01 12:59   ` Wu, Hao
  2021-02-02  1:59     ` Xu Yilun
  0 siblings, 1 reply; 6+ messages in thread
From: Wu, Hao @ 2021-02-01 12:59 UTC (permalink / raw)
  To: Xu, Yilun, gregkh, mdf, linux-fpga, linux-kernel; +Cc: trix, lgoncalv

> Subject: [PATCH v10 2/2] Documentation: fpga: dfl: Add description for DFL UIO
> support
> 
> This patch adds description for UIO support for dfl devices on DFL
> bus.
> 
> Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> Reviewed-by: Tom Rix <trix@redhat.com>
> ---
> 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.
> v6: improve the title of the userspace driver support section.
>     some word improvement.
> v7: rebased to next-20210119
> v8: some doc fixes.
> v9: some doc change since we switch to the driver in drivers/uio.
> v10: no change.
> ---
>  Documentation/fpga/dfl.rst | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
> 
> diff --git a/Documentation/fpga/dfl.rst b/Documentation/fpga/dfl.rst
> index c41ac76..e35cf87 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 +531,28 @@ 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.

Current uio_dfl doesn't have interrupt handling support, right? I guess we need
to make sure no confusion on the description here. other place looks good to me.

Hao

> +
> +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
> --
> 2.7.4


^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH v10 1/2] uio: uio_dfl: add userspace i/o driver for DFL bus
  2021-02-01  5:38 ` [PATCH v10 1/2] uio: uio_dfl: add userspace i/o driver for DFL bus Xu Yilun
@ 2021-02-01 14:12   ` Tom Rix
  0 siblings, 0 replies; 6+ messages in thread
From: Tom Rix @ 2021-02-01 14:12 UTC (permalink / raw)
  To: Xu Yilun, gregkh, mdf, linux-fpga, linux-kernel; +Cc: lgoncalv, hao.wu


On 1/31/21 9:38 PM, 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@intel.com>
> ---
> 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
> ---
>  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 147d1d9..4d01a21 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/

Yes, it is there.  Thanks!

Reviewed-by: Tom Rix <trix@redhat.com>

> +
> +	  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
> +
> +static const struct dfl_device_id uio_dfl_ids[] = {
> +	{ FME_ID, FME_FEATURE_ID_ETH_GROUP },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(dfl, uio_dfl_ids);
> +
> +static struct dfl_driver uio_dfl_driver = {
> +	.drv = {
> +		.name = DRIVER_NAME,
> +	},
> +	.id_table	= uio_dfl_ids,
> +	.probe		= uio_dfl_probe,
> +};
> +module_dfl_driver(uio_dfl_driver);
> +
> +MODULE_DESCRIPTION("Generic DFL driver for Userspace I/O devices");
> +MODULE_AUTHOR("Intel Corporation");
> +MODULE_LICENSE("GPL v2");


^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [PATCH v10 2/2] Documentation: fpga: dfl: Add description for DFL  UIO support
  2021-02-01 12:59   ` Wu, Hao
@ 2021-02-02  1:59     ` Xu Yilun
  0 siblings, 0 replies; 6+ messages in thread
From: Xu Yilun @ 2021-02-02  1:59 UTC (permalink / raw)
  To: Wu, Hao; +Cc: gregkh, mdf, linux-fpga, linux-kernel, trix, lgoncalv

On Mon, Feb 01, 2021 at 08:59:06PM +0800, Wu, Hao wrote:
> > Subject: [PATCH v10 2/2] Documentation: fpga: dfl: Add description for DFL UIO
> > support
> >
> > This patch adds description for UIO support for dfl devices on DFL
> > bus.
> >
> > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > Reviewed-by: Tom Rix <trix@redhat.com>
> > ---
> > 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.
> > v6: improve the title of the userspace driver support section.
> >     some word improvement.
> > v7: rebased to next-20210119
> > v8: some doc fixes.
> > v9: some doc change since we switch to the driver in drivers/uio.
> > v10: no change.
> > ---
> >  Documentation/fpga/dfl.rst | 23 +++++++++++++++++++++++
> >  1 file changed, 23 insertions(+)
> >
> > diff --git a/Documentation/fpga/dfl.rst b/Documentation/fpga/dfl.rst
> > index c41ac76..e35cf87 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 +531,28 @@ 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.
> 
> Current uio_dfl doesn't have interrupt handling support, right? I guess we need
> to make sure no confusion on the description here. other place looks good to me.

Will fix it.

Thanks,
Yilun

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-02-02  2:04 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-01  5:38 [PATCH v10 0/2] UIO support for dfl devices Xu Yilun
2021-02-01  5:38 ` [PATCH v10 1/2] uio: uio_dfl: add userspace i/o driver for DFL bus Xu Yilun
2021-02-01 14:12   ` Tom Rix
2021-02-01  5:38 ` [PATCH v10 2/2] Documentation: fpga: dfl: Add description for DFL UIO support Xu Yilun
2021-02-01 12:59   ` Wu, Hao
2021-02-02  1:59     ` Xu Yilun

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