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[75.142.250.213]) by smtp.gmail.com with ESMTPSA id v137sm5863135qka.110.2020.12.18.05.59.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 18 Dec 2020 05:59:19 -0800 (PST) Subject: Re: [PATCH v3 2/3] fpga: dfl: add the userspace I/O device support for DFL devices To: "Wu, Hao" , "Xu, Yilun" , "mdf@kernel.org" , "linux-fpga@vger.kernel.org" , "linux-kernel@vger.kernel.org" Cc: "gregkh@linuxfoundation.org" , "lgoncalv@redhat.com" References: <1608183881-18692-1-git-send-email-yilun.xu@intel.com> <1608183881-18692-3-git-send-email-yilun.xu@intel.com> From: Tom Rix Message-ID: <0d3f1f40-9f89-0ec2-96c4-b8b087f31382@redhat.com> Date: Fri, 18 Dec 2020 05:59:17 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: linux-fpga@vger.kernel.org On 12/18/20 12:05 AM, Wu, Hao wrote: >> Subject: [PATCH v3 2/3] fpga: dfl: add the userspace I/O device support for >> DFL devices >> >> 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. > Looks like we want to build UIO driver as the default/generic driver for DFL, > it seems fine but my concern is that UIO has its own limitation, if some day, > dfl device is extended, but UIO has limitation, then we may need to select > another one as the default driver.. or we can just match them using > id_table as we know UIO meets the requirement for those DFL devices? When we have multiple defaults, could this be handled in the configury ? Tom > >> Signed-off-by: Xu Yilun >> --- >> 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. >> v3: split the dfl.c changes out of this patch. >> some minor fixes >> --- >> drivers/fpga/Kconfig | 10 ++++ >> drivers/fpga/Makefile | 1 + >> drivers/fpga/dfl-uio-pdev.c | 110 >> ++++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 121 insertions(+) >> create mode 100644 drivers/fpga/dfl-uio-pdev.c >> >> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig >> index 5d7f0ae..7a88af9 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 feature's >> + resources, and lets the generic UIO platform device driver provide >> + support for userspace access to kernel interrupts and memory >> + locations. > If we consider this as a default driver for everybody in DFL, then we could > consider build it into the core, otherwise it always requires to be loaded > manually, right? > >> + >> 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..8847fe0 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..8c57233 >> --- /dev/null >> +++ b/drivers/fpga/dfl-uio-pdev.c >> @@ -0,0 +1,110 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * DFL driver for Userspace I/O platform devices >> + * >> + * Copyright (C) 2020 Intel Corporation, Inc. >> + */ >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +#include "dfl.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]; >> + } > How many interrupts UIO could support? or we need some > warning or just even return error here? > > Thanks > Hao > >> + >> + 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, >> +}; >> +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"); >> -- >> 2.7.4