Re: [PATCH v4 20/24] fpga: dfl: add FPGA Accelerated Function Unit driver basic framework

[Wu Hao]

On Thu, Apr 05, 2018 at 01:26:57PM -0500, Alan Tull wrote:
> On Tue, Feb 13, 2018 at 3:24 AM, Wu Hao <hao.wu@xxxxxxxxx> wrote:
> 
> Hi Hao,
> 
> One minor thing below.
> 
> > On DFL FPGA devices, the Accelerated Function Unit (AFU), can be
> > reprogrammed for different functions. It connects to the FPGA
> > infrastructure("blue bistream") via a Port. Port CSRs are implemented
> > separately from the AFU CSRs to provide control and status of the Port.
> > Once valid green bitstream is programmed into the AFU, it allows access
> > to the AFU CSRs in the AFU MMIO space.
> >
> > This patch only implements basic driver framework for AFU, including
> > device file operation framework.
> >
> > Signed-off-by: Tim Whisonant <tim.whisonant@xxxxxxxxx>
> > Signed-off-by: Enno Luebbers <enno.luebbers@xxxxxxxxx>
> > Signed-off-by: Shiva Rao <shiva.rao@xxxxxxxxx>
> > Signed-off-by: Christopher Rauer <christopher.rauer@xxxxxxxxx>
> > Signed-off-by: Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
> > Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
> > ---
> > v3: rename driver to dfl-afu-main.c
> > v4: rename to dfl-port and fix SPDX license issue.
> > ---
> >  drivers/fpga/Kconfig        |   9 +++
> >  drivers/fpga/Makefile       |   2 +
> >  drivers/fpga/dfl-afu-main.c | 159 ++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 170 insertions(+)
> >  create mode 100644 drivers/fpga/dfl-afu-main.c
> >
> > diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> > index 65d54a4..4c6b45f 100644
> > --- a/drivers/fpga/Kconfig
> > +++ b/drivers/fpga/Kconfig
> > @@ -168,6 +168,15 @@ config FPGA_DFL_FME_REGION
> >         help
> >           Say Y to enable FPGA Region driver for FPGA Management Engine.
> >
> > +config FPGA_DFL_AFU
> > +       tristate "FPGA DFL AFU Driver"
> > +       depends on FPGA_DFL
> > +       help
> > +         This is the driver for FPGA Accelerated Function Unit (AFU) which
> > +         implements AFU and Port management features. A User AFU connects
> > +         to the FPGA infrastructure via a Port. There may be more than 1
> > +         Port/AFU per DFL based FPGA device.
> > +
> >  config FPGA_DFL_PCI
> >         tristate "FPGA Device Feature List (DFL) PCIe Device Driver"
> >         depends on PCI && FPGA_DFL
> > diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
> > index 163894e..5c9607b 100644
> > --- a/drivers/fpga/Makefile
> > +++ b/drivers/fpga/Makefile
> > @@ -34,8 +34,10 @@ obj-$(CONFIG_FPGA_DFL_FME)           += dfl-fme.o
> >  obj-$(CONFIG_FPGA_DFL_FME_MGR)         += dfl-fme-mgr.o
> >  obj-$(CONFIG_FPGA_DFL_FME_BRIDGE)      += dfl-fme-br.o
> >  obj-$(CONFIG_FPGA_DFL_FME_REGION)      += dfl-fme-region.o
> > +obj-$(CONFIG_FPGA_DFL_AFU)             += dfl-afu.o
> >
> >  dfl-fme-objs := dfl-fme-main.o dfl-fme-pr.o
> > +dfl-afu-objs := dfl-afu-main.o
> >
> >  # Drivers for FPGAs which implement DFL
> >  obj-$(CONFIG_FPGA_DFL_PCI)             += dfl-pci.o
> > diff --git a/drivers/fpga/dfl-afu-main.c b/drivers/fpga/dfl-afu-main.c
> > new file mode 100644
> > index 0000000..70db28c
> > --- /dev/null
> > +++ b/drivers/fpga/dfl-afu-main.c
> > @@ -0,0 +1,159 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Driver for FPGA Accelerated Function Unit (AFU)
> > + *
> > + * Copyright (C) 2017 Intel Corporation, Inc.
> > + *
> > + * Authors:
> > + *   Wu Hao <hao.wu@xxxxxxxxx>
> > + *   Xiao Guangrong <guangrong.xiao@xxxxxxxxxxxxxxx>
> > + *   Joseph Grecco <joe.grecco@xxxxxxxxx>
> > + *   Enno Luebbers <enno.luebbers@xxxxxxxxx>
> > + *   Tim Whisonant <tim.whisonant@xxxxxxxxx>
> > + *   Ananda Ravuri <ananda.ravuri@xxxxxxxxx>
> > + *   Henry Mitchel <henry.mitchel@xxxxxxxxx>
> > + */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +
> > +#include "dfl.h"
> > +
> > +static int port_hdr_init(struct platform_device *pdev, struct feature *feature)
> > +{
> > +       dev_dbg(&pdev->dev, "PORT HDR Init.\n");
> > +
> > +       return 0;
> > +}
> > +
> > +static void port_hdr_uinit(struct platform_device *pdev,
> > +                          struct feature *feature)
> > +{
> > +       dev_dbg(&pdev->dev, "PORT HDR UInit.\n");
> > +}
> > +
> > +static const struct feature_ops port_hdr_ops = {
> > +       .init = port_hdr_init,
> > +       .uinit = port_hdr_uinit,
> > +};
> > +
> > +static struct feature_driver port_feature_drvs[] = {
> > +       {
> > +               .id = PORT_FEATURE_ID_HEADER,
> > +               .ops = &port_hdr_ops,
> > +       },
> > +       {
> > +               .ops = NULL,
> > +       }
> > +};
> > +
> > +static int afu_open(struct inode *inode, struct file *filp)
> > +{
> > +       struct platform_device *fdev = fpga_inode_to_feature_dev(inode);
> > +       struct feature_platform_data *pdata;
> > +       int ret;
> > +
> > +       pdata = dev_get_platdata(&fdev->dev);
> > +       if (WARN_ON(!pdata))
> > +               return -ENODEV;
> > +
> > +       ret = feature_dev_use_begin(pdata);
> > +       if (ret)
> > +               return ret;
> > +
> > +       dev_dbg(&fdev->dev, "Device File Open\n");
> > +       filp->private_data = fdev;
> > +
> > +       return 0;
> > +}
> > +
> > +static int afu_release(struct inode *inode, struct file *filp)
> > +{
> > +       struct platform_device *pdev = filp->private_data;
> > +       struct feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
> > +
> > +       dev_dbg(&pdev->dev, "Device File Release\n");
> > +
> > +       feature_dev_use_end(pdata);
> > +
> > +       return 0;
> > +}
> > +
> > +static long afu_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> > +{
> > +       struct platform_device *pdev = filp->private_data;
> > +       struct feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
> > +       struct feature *f;
> > +       long ret;
> > +
> > +       dev_dbg(&pdev->dev, "%s cmd 0x%x\n", __func__, cmd);
> > +
> > +       switch (cmd) {
> > +       default:
> > +               /*
> > +                * Let sub-feature's ioctl function to handle the cmd
> > +                * Sub-feature's ioctl returns -ENODEV when cmd is not
> > +                * handled in this sub feature, and returns 0 and other
> > +                * error code if cmd is handled.
> > +                */
> > +               fpga_dev_for_each_feature(pdata, f)
> > +                       if (f->ops && f->ops->ioctl) {
> > +                               ret = f->ops->ioctl(pdev, f, cmd, arg);
> > +                               if (ret == -ENODEV)
> > +                                       continue;
> > +                               else
> > +                                       return ret;
> 
> The continue..else isn't needed.  Could just be
> if (ret != -ENODEV)
>         return ret;

Agree, will fix this in the next version. Thanks.

Hao

> 
> Thanks,
> Alan
> 
> > +                       }
> > +       }
> > +
> > +       return -EINVAL;
> > +}
> > +
> > +static const struct file_operations afu_fops = {
> > +       .owner = THIS_MODULE,
> > +       .open = afu_open,
> > +       .release = afu_release,
> > +       .unlocked_ioctl = afu_ioctl,
> > +};
> > +
> > +static int afu_probe(struct platform_device *pdev)
> > +{
> > +       int ret;
> > +
> > +       dev_dbg(&pdev->dev, "%s\n", __func__);
> > +
> > +       ret = fpga_dev_feature_init(pdev, port_feature_drvs);
> > +       if (ret)
> > +               return ret;
> > +
> > +       ret = fpga_register_dev_ops(pdev, &afu_fops, THIS_MODULE);
> > +       if (ret)
> > +               fpga_dev_feature_uinit(pdev);
> > +
> > +       return ret;
> > +}
> > +
> > +static int afu_remove(struct platform_device *pdev)
> > +{
> > +       dev_dbg(&pdev->dev, "%s\n", __func__);
> > +
> > +       fpga_dev_feature_uinit(pdev);
> > +       fpga_unregister_dev_ops(pdev);
> > +
> > +       return 0;
> > +}
> > +
> > +static struct platform_driver afu_driver = {
> > +       .driver = {
> > +               .name    = FPGA_FEATURE_DEV_PORT,
> > +       },
> > +       .probe   = afu_probe,
> > +       .remove  = afu_remove,
> > +};
> > +
> > +module_platform_driver(afu_driver);
> > +
> > +MODULE_DESCRIPTION("FPGA Accelerated Function Unit driver");
> > +MODULE_AUTHOR("Intel Corporation");
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_ALIAS("platform:dfl-port");
> > --
> > 2.7.4
> >