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Message-ID: <20201215020608.GB14854@yilunxu-OptiPlex-7050>
Date: Tue, 15 Dec 2020 10:06:08 +0800
From: Xu Yilun <yilun.xu@...el.com>
To: Tom Rix <trix@...hat.com>
Cc: mdf@...nel.org, linux-fpga@...r.kernel.org,
linux-kernel@...r.kernel.org, gregkh@...uxfoundation.org,
lgoncalv@...hat.com, hao.wu@...el.com
Subject: Re: [PATCH v2 1/2] fpga: dfl: add the userspace I/O device support
for DFL devices
On Mon, Dec 14, 2020 at 02:03:03PM -0800, Tom Rix wrote:
>
>
> On 12/13/20 7:36 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 leverages the uio_pdrv_genirq, it adds the uio_pdrv_genirq
> > platform device with the DFL device's resources, and let the generic UIO
> > platform device driver provide support to userspace access to kernel
> > interrupts and memory locations.
> >
> > The driver matches DFL devices in a different way. It has no device id
> > table, instead it matches any DFL device which could not be handled by
> > other DFL drivers. For this purpose, a match() ops is added to the dfl
> > driver, to allow dfl drivers have their own matching algorithem instead
> > of the standard id_table matching.
>
> Because (*match) is added, this change is doing two things.
>
> In the next version, please split the new interface out, i believe these are
>
> the dfl.c/h changes.
Yes, I'll split it out.
>
> >
> > Signed-off-by: Xu Yilun <yilun.xu@...el.com>
> > ---
> > v2: 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.
> > fix some comments.
> > ---
> > drivers/fpga/Kconfig | 10 ++++
> > drivers/fpga/Makefile | 1 +
> > drivers/fpga/dfl-uio-pdev.c | 108 ++++++++++++++++++++++++++++++++++++++++++++
> > drivers/fpga/dfl.c | 22 +++++++--
> > include/linux/dfl.h | 7 +++
> > 5 files changed, 143 insertions(+), 5 deletions(-)
> > create mode 100644 drivers/fpga/dfl-uio-pdev.c
> >
> > diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> > index 5d7f0ae..eb8a616 100644
> > --- a/drivers/fpga/Kconfig
> > +++ b/drivers/fpga/Kconfig
> > @@ -202,6 +202,16 @@ config FPGA_DFL_NIOS_INTEL_PAC_N3000
> > the card. It also instantiates the SPI master (spi-altera) for
> > the card's BMC (Board Management Controller).
> >
> > +config FPGA_DFL_UIO_PDEV
> > + tristate "FPGA DFL Driver for Userspace I/O platform devices"
> > + depends on FPGA_DFL && UIO_PDRV_GENIRQ
> > + help
> > + Enable this to allow some DFL drivers be written in userspace. It
> > + adds the uio_pdrv_genirq platform device with the DFL device's
> DFL feature's
Will change it.
> > + resources, and lets the generic UIO platform device driver provide
> > + support to userspace access to kernel interrupts and memory
> support for userspace
Will change it.
> > + locations.
> > +
> > config FPGA_DFL_PCI
> > tristate "FPGA DFL PCIe Device Driver"
> > depends on PCI && FPGA_DFL
> > diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
> > index 18dc9885..e07b3d5 100644
> > --- a/drivers/fpga/Makefile
> > +++ b/drivers/fpga/Makefile
> > @@ -45,6 +45,7 @@ dfl-afu-objs := dfl-afu-main.o dfl-afu-region.o dfl-afu-dma-region.o
> > dfl-afu-objs += dfl-afu-error.o
> >
> > obj-$(CONFIG_FPGA_DFL_NIOS_INTEL_PAC_N3000) += dfl-n3000-nios.o
> > +obj-$(CONFIG_FPGA_DFL_UIO_PDEV) += dfl-uio-pdev.o
> This does not really align with += dfl-pci.o, add another tab.
Will change it.
> >
> > # Drivers for FPGAs which implement DFL
> > obj-$(CONFIG_FPGA_DFL_PCI) += dfl-pci.o
> > diff --git a/drivers/fpga/dfl-uio-pdev.c b/drivers/fpga/dfl-uio-pdev.c
> > new file mode 100644
> > index 0000000..68ede04
> > --- /dev/null
> > +++ b/drivers/fpga/dfl-uio-pdev.c
> > @@ -0,0 +1,108 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * DFL driver for Userspace I/O platform devices
> > + *
> > + * Copyright (C) 2020 Intel Corporation, Inc.
> > + */
> > +#include <linux/dfl.h>
> > +#include <linux/errno.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/slab.h>
> > +#include <linux/uio_driver.h>
> > +
> > +#define DRIVER_NAME "dfl-uio-pdev"
> > +
> > +static struct dfl_driver dfl_uio_pdev_driver;
> > +
> > +static int check_for_other_drv_match(struct device_driver *drv, void *data)
> > +{
> > + struct dfl_driver *ddrv = to_dfl_drv(drv);
> > + struct dfl_device *ddev = data;
> > +
> > + /* skip myself */
> > + if (ddrv == &dfl_uio_pdev_driver)
> > + return 0;
> > +
> > + return dfl_match_device(ddev, ddrv);
> > +}
> > +
> > +static int dfl_uio_pdev_match(struct dfl_device *ddev)
> > +{
> > + /*
> > + * If any other driver wants the device, leave the device to this other
> > + * driver.
> > + */
> > + if (bus_for_each_drv(&dfl_bus_type, NULL, ddev, check_for_other_drv_match))
> > + return 0;
> > +
> > + return 1;
> > +}
> > +
> > +static int dfl_uio_pdev_probe(struct dfl_device *ddev)
> > +{
> > + struct device *dev = &ddev->dev;
> > + struct platform_device_info pdevinfo = { 0 };
> > + struct uio_info uio_pdata = { 0 };
> > + struct platform_device *uio_pdev;
> > + struct resource *res;
> > + int i;
> > +
> > + pdevinfo.name = "uio_pdrv_genirq";
> > +
> > + res = kcalloc(ddev->num_irqs + 1, sizeof(*res), GFP_KERNEL);
> > + if (!res)
> > + return -ENOMEM;
> > +
> > + res[0].parent = &ddev->mmio_res;
> > + res[0].flags = IORESOURCE_MEM;
> > + res[0].start = ddev->mmio_res.start;
> > + res[0].end = ddev->mmio_res.end;
> > +
> > + /* then add irq resource */
> > + for (i = 0; i < ddev->num_irqs; i++) {
> > + res[i + 1].flags = IORESOURCE_IRQ;
> > + res[i + 1].start = ddev->irqs[i];
> > + res[i + 1].end = ddev->irqs[i];
> > + }
> > +
> > + uio_pdata.name = DRIVER_NAME;
> > + uio_pdata.version = "0";
> > +
> > + pdevinfo.res = res;
> > + pdevinfo.num_res = ddev->num_irqs + 1;
> > + pdevinfo.parent = &ddev->dev;
> > + pdevinfo.id = PLATFORM_DEVID_AUTO;
> > + pdevinfo.data = &uio_pdata;
> > + pdevinfo.size_data = sizeof(uio_pdata);
> > +
> > + uio_pdev = platform_device_register_full(&pdevinfo);
> > + if (!IS_ERR(uio_pdev))
> > + dev_set_drvdata(dev, uio_pdev);
> > +
> > + kfree(res);
> > +
> > + return PTR_ERR_OR_ZERO(uio_pdev);
> > +}
> > +
> > +static void dfl_uio_pdev_remove(struct dfl_device *ddev)
> > +{
> > + struct platform_device *uio_pdev = dev_get_drvdata(&ddev->dev);
> > +
> > + platform_device_unregister(uio_pdev);
> > +}
> > +
> > +static struct dfl_driver dfl_uio_pdev_driver = {
> > + .drv = {
> > + .name = DRIVER_NAME,
> > + },
> > + .match = dfl_uio_pdev_match,
> > + .probe = dfl_uio_pdev_probe,
> > + .remove = dfl_uio_pdev_remove,
> > +};
> Could move this to the top and remove the forward decl.
I think it may be unnecessary. If we move it to the top, then we should
forward declare the 3 callbacks.
> > +module_dfl_driver(dfl_uio_pdev_driver);
> > +
> > +MODULE_DESCRIPTION("DFL driver for Userspace I/O platform devices");
> > +MODULE_AUTHOR("Intel Corporation");
> > +MODULE_LICENSE("GPL v2");
> > diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> > index 511b20f..dd90111 100644
> > --- a/drivers/fpga/dfl.c
> > +++ b/drivers/fpga/dfl.c
> > @@ -256,12 +256,13 @@ dfl_match_one_device(const struct dfl_device_id *id, struct dfl_device *ddev)
> > return NULL;
> > }
> >
> > -static int dfl_bus_match(struct device *dev, struct device_driver *drv)
> > +int dfl_match_device(struct dfl_device *ddev, struct dfl_driver *ddrv)
> > {
> > - struct dfl_device *ddev = to_dfl_dev(dev);
> > - struct dfl_driver *ddrv = to_dfl_drv(drv);
> > const struct dfl_device_id *id_entry;
> >
> > + if (ddrv->match)
> > + return ddrv->match(ddev);
> > +
> > id_entry = ddrv->id_table;
> > if (id_entry) {
> > while (id_entry->feature_id) {
> > @@ -275,6 +276,15 @@ static int dfl_bus_match(struct device *dev, struct device_driver *drv)
> >
> > return 0;
> > }
> > +EXPORT_SYMBOL_GPL(dfl_match_device);
> > +
> > +static int dfl_bus_match(struct device *dev, struct device_driver *drv)
> > +{
> > + struct dfl_device *ddev = to_dfl_dev(dev);
> > + struct dfl_driver *ddrv = to_dfl_drv(drv);
> > +
> > + return dfl_match_device(ddev, ddrv);
> > +}
> >
> > static int dfl_bus_probe(struct device *dev)
> > {
> > @@ -328,7 +338,7 @@ static struct attribute *dfl_dev_attrs[] = {
> > };
> > ATTRIBUTE_GROUPS(dfl_dev);
> >
> > -static struct bus_type dfl_bus_type = {
> > +struct bus_type dfl_bus_type = {
> > .name = "dfl",
> > .match = dfl_bus_match,
> > .probe = dfl_bus_probe,
> > @@ -336,6 +346,7 @@ static struct bus_type dfl_bus_type = {
> > .uevent = dfl_bus_uevent,
> > .dev_groups = dfl_dev_groups,
> > };
> > +EXPORT_SYMBOL_GPL(dfl_bus_type);
> >
> > static void release_dfl_dev(struct device *dev)
> > {
> > @@ -469,7 +480,8 @@ static int dfl_devs_add(struct dfl_feature_platform_data *pdata)
> >
> > int __dfl_driver_register(struct dfl_driver *dfl_drv, struct module *owner)
> > {
> > - if (!dfl_drv || !dfl_drv->probe || !dfl_drv->id_table)
> > + if (!dfl_drv || !dfl_drv->probe ||
> > + (!dfl_drv->id_table && !dfl_drv->match))
> > return -EINVAL;
> >
> > dfl_drv->drv.owner = owner;
> > diff --git a/include/linux/dfl.h b/include/linux/dfl.h
> > index 6cc1098..7bd97ec 100644
> > --- a/include/linux/dfl.h
> > +++ b/include/linux/dfl.h
> > @@ -11,6 +11,8 @@
> > #include <linux/device.h>
> > #include <linux/mod_devicetable.h>
> >
> > +extern struct bus_type dfl_bus_type;
>
> Why is this needed ?
>
> This is a public interface, likely should happen somewhere in drivers/fpga
The dfl-uio-pdev module is using this variable. Do you mean we should
move it to DFL internal header file, drivers/fpga/dfl.h ?
>
> > +
> > /**
> > * enum dfl_id_type - define the DFL FIU types
> > */
> > @@ -51,6 +53,8 @@ struct dfl_device {
> > * @drv: driver model structure.
> > * @id_table: pointer to table of device IDs the driver is interested in.
> > * { } member terminated.
> > + * @match: returns a positive value if given device can be handled by the
> returns one
Will change it.
> > + * driver and zero otherwise. If NULL, matching is based on id_table.
> > * @probe: mandatory callback for device binding.
> > * @remove: callback for device unbinding.
> > */
> > @@ -58,6 +62,7 @@ struct dfl_driver {
> > struct device_driver drv;
> > const struct dfl_device_id *id_table;
> >
> > + int (*match)(struct dfl_device *dfl_dev);
> > int (*probe)(struct dfl_device *dfl_dev);
> > void (*remove)(struct dfl_device *dfl_dev);
> > };
> > @@ -65,6 +70,8 @@ struct dfl_driver {
> > #define to_dfl_dev(d) container_of(d, struct dfl_device, dev)
> > #define to_dfl_drv(d) container_of(d, struct dfl_driver, drv)
> >
> > +int dfl_match_device(struct dfl_device *ddev, struct dfl_driver *ddrv);
>
> Is it really necessary put this as a public interface ?
I may move it to drivers/fpga/dfl.h
Thanks,
Yilun
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