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Message-ID: <78c66206-f264-9a95-e782-2195fc86306f@redhat.com>
Date: Mon, 19 Oct 2020 07:01:34 -0700
From: Tom Rix <trix@...hat.com>
To: Xu Yilun <yilun.xu@...el.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 2/2] fpga: dfl: add the userspace I/O device support for
DFL devices
On 10/18/20 9:16 PM, Xu Yilun wrote:
> On Fri, Oct 16, 2020 at 09:36:00AM -0700, Tom Rix wrote:
>> On 10/15/20 11:02 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.
>>>
>>> Signed-off-by: Xu Yilun <yilun.xu@...el.com>
>>> ---
>>> drivers/fpga/Kconfig | 10 ++++++
>>> drivers/fpga/Makefile | 1 +
>>> drivers/fpga/dfl-uio-pdev.c | 83 +++++++++++++++++++++++++++++++++++++++++++++
>>> 3 files changed, 94 insertions(+)
>>> create mode 100644 drivers/fpga/dfl-uio-pdev.c
>>>
>>> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
>>> index 5d7f0ae..e054722 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
>>> + resources, and let the generic UIO platform device driver provide
>> 'and lets the'
> Yes.
>
>>> + support to userspace access to kernel interrupts and memory
>>> + 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
>>>
>>> # 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..d35b846
>>> --- /dev/null
>>> +++ b/drivers/fpga/dfl-uio-pdev.c
>>> @@ -0,0 +1,83 @@
>>> +// 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 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, idx = 0;
>> idx is not needed.
> I could remove the idx. But I think I could ++res during the resource
> filling.
ok.
You may want to check the code generation, my feeling is ++res will be worse.
Tom
>
> Thanks,
> Yilun
>
>>> +
>>> + pdevinfo.name = "uio_pdrv_genirq";
>>> +
>>> + res = kcalloc(ddev->num_irqs + 1, sizeof(*res), GFP_KERNEL);
>>> + if (!res)
>>> + return -ENOMEM;
>>> +
>>> + res[idx].parent = &ddev->mmio_res;
>> res[0].parent =
>>> + res[idx].flags = IORESOURCE_MEM;
>>> + res[idx].start = ddev->mmio_res.start;
>>> + res[idx].end = ddev->mmio_res.end;
>>> + ++idx;
>>> +
>>> + /* then add irq resource */
>>> + for (i = 0; i < ddev->num_irqs; i++) {
>>> + res[idx].flags = IORESOURCE_IRQ;
>> res[i+1].flags =
>>
>> Tom
>>
>>> + res[idx].start = ddev->irqs[i];
>>> + res[idx].end = ddev->irqs[i];
>>> + ++idx;
>>> + }
>>> +
>>> + uio_pdata.name = DRIVER_NAME;
>>> + uio_pdata.version = "0";
>>> +
>>> + pdevinfo.res = res;
>>> + pdevinfo.num_res = idx;
>>> + 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,
>>> + },
>>> + .probe = dfl_uio_pdev_probe,
>>> + .remove = dfl_uio_pdev_remove,
>>> +};
>>> +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");
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