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[75.142.250.213]) by smtp.gmail.com with ESMTPSA id b73sm12350502qkc.87.2020.12.07.04.42.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Dec 2020 04:43:00 -0800 (PST) Subject: Re: [RFC] fpga: dfl: a prototype uio driver To: "Wu, Hao" , "Xu, Yilun" Cc: "gregkh@linuxfoundation.org" , "mdf@kernel.org" , "linux-kernel@vger.kernel.org" , "linux-fpga@vger.kernel.org" References: <20201206215554.350230-1-trix@redhat.com> <20201207034950.GA29754@yilunxu-OptiPlex-7050> From: Tom Rix Message-ID: <56369ecc-5dfb-c896-d114-2ff59724ff97@redhat.com> Date: Mon, 7 Dec 2020 04:42:58 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.3.1 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 12/6/20 10:24 PM, Wu, Hao wrote: >> Subject: Re: [RFC] fpga: dfl: a prototype uio driver >> >> On Sun, Dec 06, 2020 at 01:55:54PM -0800, trix@redhat.com wrote: >>> From: Tom Rix >>> >>> >From [PATCH 0/2] UIO support for dfl devices >>> https://lore.kernel.org/linux-fpga/1602828151-24784-1-git-send-email- >> yilun.xu@intel.com/ >>> Here is an idea to have uio support with no driver override. >>> >>> This makes UIO the primary driver interface because every feature >>> will have one and makes the existing platform driver interface >>> secondary. There will be a new burden for locking write access when >>> they compete. >>> >>> Example shows finding the fpga's temperture. >> Hi Tom: >> >> Thanks for the idea and detailed illustrate with the patch. I see it >> abandons the driver_override and expose all the DFL devices to userspace >> by UIO. I'd like to see if we could get some more comments on it. > This allows concurrent access from both userspace and kernel space driver > to the same feature device? conflicts? Yes conflicts, that is why a lock is needed and the unpleasant part of this idea. Another way is split them and have uio for the unclaimed feature id's Tom > > Hao > >> Thanks, >> Yilun >> >>> Signed-off-by: Tom Rix >>> --- >>> drivers/fpga/dfl-fme-main.c | 9 +++- >>> drivers/fpga/dfl-uio.c | 96 +++++++++++++++++++++++++++++++++++++ >>> drivers/fpga/dfl.c | 44 ++++++++++++++++- >>> drivers/fpga/dfl.h | 9 ++++ >>> uio.c | 56 ++++++++++++++++++++++ >>> 5 files changed, 212 insertions(+), 2 deletions(-) >>> create mode 100644 drivers/fpga/dfl-uio.c >>> create mode 100644 uio.c >>> >>> diff --git a/drivers/fpga/dfl-fme-main.c b/drivers/fpga/dfl-fme-main.c >>> index 037dc4f946f0..3323e90a18c4 100644 >>> --- a/drivers/fpga/dfl-fme-main.c >>> +++ b/drivers/fpga/dfl-fme-main.c >>> @@ -709,12 +709,18 @@ static int fme_probe(struct platform_device >> *pdev) >>> if (ret) >>> goto dev_destroy; >>> >>> - ret = dfl_fpga_dev_ops_register(pdev, &fme_fops, THIS_MODULE); >>> + ret = dfl_fpga_dev_feature_init_uio(pdev, DFH_TYPE_FIU); >>> if (ret) >>> goto feature_uinit; >>> >>> + ret = dfl_fpga_dev_ops_register(pdev, &fme_fops, THIS_MODULE); >>> + if (ret) >>> + goto feature_uinit_uio; >>> + >>> return 0; >>> >>> +feature_uinit_uio: >>> + dfl_fpga_dev_feature_uinit_uio(pdev, DFH_TYPE_FIU); >>> feature_uinit: >>> dfl_fpga_dev_feature_uinit(pdev); >>> dev_destroy: >>> @@ -726,6 +732,7 @@ exit: >>> static int fme_remove(struct platform_device *pdev) >>> { >>> dfl_fpga_dev_ops_unregister(pdev); >>> + dfl_fpga_dev_feature_uinit_uio(pdev, DFH_TYPE_FIU); >>> dfl_fpga_dev_feature_uinit(pdev); >>> fme_dev_destroy(pdev); >>> >>> diff --git a/drivers/fpga/dfl-uio.c b/drivers/fpga/dfl-uio.c >>> new file mode 100644 >>> index 000000000000..7610ee0b19dc >>> --- /dev/null >>> +++ b/drivers/fpga/dfl-uio.c >>> @@ -0,0 +1,96 @@ >>> +/* SPDX-License-Identifier: GPL-2.0 */ >>> +/* >>> + * prototype dfl uio driver >>> + * >>> + * Copyright Tom Rix 2020 >>> + */ >>> +#include >>> +#include "dfl.h" >>> + >>> +static irqreturn_t dfl_uio_handler(int irq, struct uio_info *info) >>> +{ >>> + return IRQ_HANDLED; >>> +} >>> + >>> +static int dfl_uio_mmap(struct uio_info *info, struct vm_area_struct *vma) >>> +{ >>> + int ret = -ENODEV; >>> + return ret; >>> +} >>> + >>> +static int dfl_uio_open(struct uio_info *info, struct inode *inode) >>> +{ >>> + int ret = -ENODEV; >>> + struct dfl_feature *feature = container_of(info, struct dfl_feature, >> uio); >>> + if (feature->dev) >>> + mutex_lock(&feature->lock); >>> + >>> + ret = 0; >>> + return ret; >>> +} >>> + >>> +static int dfl_uio_release(struct uio_info *info, struct inode *inode) >>> +{ >>> + int ret = -ENODEV; >>> + struct dfl_feature *feature = container_of(info, struct dfl_feature, >> uio); >>> + if (feature->dev) >>> + mutex_unlock(&feature->lock); >>> + >>> + ret = 0; >>> + return ret; >>> +} >>> + >>> +static int dfl_uio_irqcontrol(struct uio_info *info, s32 irq_on) >>> +{ >>> + int ret = -ENODEV; >>> + return ret; >>> +} >>> + >>> +int dfl_uio_add(struct dfl_feature *feature) >>> +{ >>> + struct uio_info *uio = &feature->uio; >>> + struct resource *res = >>> + &feature->dev->resource[feature->resource_index]; >>> + int ret = 0; >>> + >>> + uio->name = kasprintf(GFP_KERNEL, "dfl-uio-%llx", feature->id); >>> + if (!uio->name) { >>> + ret = -ENOMEM; >>> + goto exit; >>> + } >>> + >>> + uio->version = "0.1"; >>> + uio->mem[0].memtype = UIO_MEM_PHYS; >>> + uio->mem[0].addr = res->start & PAGE_MASK; >>> + uio->mem[0].offs = res->start & ~PAGE_MASK; >>> + uio->mem[0].size = (uio->mem[0].offs + resource_size(res) >>> + + PAGE_SIZE - 1) & PAGE_MASK; >>> + /* How are nr_irqs > 1 handled ??? */ >>> + if (feature->nr_irqs == 1) >>> + uio->irq = feature->irq_ctx[0].irq; >>> + uio->handler = dfl_uio_handler; >>> + //uio->mmap = dfl_uio_mmap; >>> + uio->open = dfl_uio_open; >>> + uio->release = dfl_uio_release; >>> + uio->irqcontrol = dfl_uio_irqcontrol; >>> + >>> + ret = uio_register_device(&feature->dev->dev, uio); >>> + if (ret) >>> + goto err_register; >>> + >>> +exit: >>> + return ret; >>> +err_register: >>> + kfree(uio->name); >>> + goto exit; >>> +} >>> +EXPORT_SYMBOL_GPL(dfl_uio_add); >>> + >>> +int dfl_uio_remove(struct dfl_feature *feature) >>> +{ >>> + uio_unregister_device(&feature->uio); >>> + kfree(feature->uio.name); >>> + return 0; >>> +} >>> +EXPORT_SYMBOL_GPL(dfl_uio_remove); >>> + >>> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c >>> index 1305be48037d..af2cd3d1b5f6 100644 >>> --- a/drivers/fpga/dfl.c >>> +++ b/drivers/fpga/dfl.c >>> @@ -603,6 +603,7 @@ static int dfl_feature_instance_init(struct >> platform_device *pdev, >>> } >>> >>> feature->ops = drv->ops; >>> + mutex_init(&feature->lock); >>> >>> return ret; >>> } >>> @@ -663,10 +664,51 @@ exit: >>> } >>> EXPORT_SYMBOL_GPL(dfl_fpga_dev_feature_init); >>> >>> +int dfl_fpga_dev_feature_init_uio(struct platform_device *pdev, int >> dfh_type) { >>> + struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev- >>> dev); >>> + struct dfl_feature *feature; >>> + int ret; >>> + >>> + dfl_fpga_dev_for_each_feature(pdata, feature) { >>> + if (dfh_type == DFH_TYPE_FIU) { >>> + if (feature->id == FEATURE_ID_FIU_HEADER || >>> + feature->id == FEATURE_ID_AFU) >>> + continue; >>> + >>> + ret = dfl_uio_add(feature); >>> + if (ret) >>> + goto exit; >>> + } >>> + } >>> + >>> + return 0; >>> +exit: >>> + dfl_fpga_dev_feature_uinit_uio(pdev, dfh_type); >>> + return ret; >>> +} >>> +EXPORT_SYMBOL_GPL(dfl_fpga_dev_feature_init_uio); >>> + >>> +int dfl_fpga_dev_feature_uinit_uio(struct platform_device *pdev, int >> dfh_type) { >>> + struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev- >>> dev); >>> + struct dfl_feature *feature; >>> + int ret = 0; >>> + >>> + dfl_fpga_dev_for_each_feature(pdata, feature) { >>> + if (dfh_type == DFH_TYPE_FIU) { >>> + if (feature->id == FEATURE_ID_FIU_HEADER || >>> + feature->id == FEATURE_ID_AFU) >>> + continue; >>> + >>> + ret |= dfl_uio_remove(feature); >>> + } >>> + } >>> + return ret; >>> +} >>> +EXPORT_SYMBOL_GPL(dfl_fpga_dev_feature_uinit_uio); >>> + >>> static void dfl_chardev_uinit(void) >>> { >>> int i; >>> - >>> for (i = 0; i < DFL_FPGA_DEVT_MAX; i++) >>> if (MAJOR(dfl_chrdevs[i].devt)) { >>> unregister_chrdev_region(dfl_chrdevs[i].devt, >>> diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h >>> index a85d1cd7a130..fde0fc902d4d 100644 >>> --- a/drivers/fpga/dfl.h >>> +++ b/drivers/fpga/dfl.h >>> @@ -26,6 +26,7 @@ >>> #include >>> #include >>> #include >>> +#include >>> #include >>> >>> /* maximum supported number of ports */ >>> @@ -232,6 +233,7 @@ struct dfl_feature_irq_ctx { >>> * struct dfl_feature - sub feature of the feature devices >>> * >>> * @dev: ptr to pdev of the feature device which has the sub feature. >>> + * @uio: uio interface for feature. >>> * @id: sub feature id. >>> * @index: unique identifier for an sub feature within the feature device. >>> * It is possible that multiply sub features with same feature id are >>> @@ -248,6 +250,8 @@ struct dfl_feature_irq_ctx { >>> */ >>> struct dfl_feature { >>> struct platform_device *dev; >>> + struct uio_info uio; >>> + struct mutex lock; /* serialize dev and uio */ >>> u64 id; >>> int index; >>> int resource_index; >>> @@ -360,6 +364,11 @@ void dfl_fpga_dev_feature_uinit(struct >> platform_device *pdev); >>> int dfl_fpga_dev_feature_init(struct platform_device *pdev, >>> struct dfl_feature_driver *feature_drvs); >>> >>> +int dfl_fpga_dev_feature_init_uio(struct platform_device *pdev, int >> dfh_type); >>> +int dfl_fpga_dev_feature_uinit_uio(struct platform_device *pdev, int >> dfh_type); >>> +int dfl_uio_add(struct dfl_feature *feature); >>> +int dfl_uio_remove(struct dfl_feature *feature); >>> + >>> int dfl_fpga_dev_ops_register(struct platform_device *pdev, >>> const struct file_operations *fops, >>> struct module *owner); >>> diff --git a/uio.c b/uio.c >>> new file mode 100644 >>> index 000000000000..50210aab4822 >>> --- /dev/null >>> +++ b/uio.c >>> @@ -0,0 +1,56 @@ >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> + >>> +int main() >>> +{ >>> + int fd; >>> + uint64_t *ptr; >>> + unsigned page_size=sysconf(_SC_PAGESIZE); >>> + struct stat sb; >>> + >>> + /* >>> + * this is fid 1, thermal mgt >>> + * ex/ >>> + * # cat /sys/class/hwmon/hwmon3/temp1_input >>> + * 39000 >>> + */ >>> + fd = open("/dev/uio0", O_RDONLY|O_SYNC); >>> + if (fd < 0) { >>> + perror("uio open:"); >>> + return errno; >>> + } >>> + >>> + ptr = (uint64_t *) mmap(NULL, page_size, PROT_READ, MAP_SHARED, >> fd, 0); >>> + if (!ptr) { >>> + perror("uio mmap:"); >>> + } else { >>> + >>> + /* from dfl-fme-main.c : >>> + * >>> + * #define FME_THERM_RDSENSOR_FMT1 0x10 >>> + * #define FPGA_TEMPERATURE GENMASK_ULL(6, 0) >>> + * >>> + * case hwmon_temp_input: >>> + * v = readq(feature->ioaddr + >> FME_THERM_RDSENSOR_FMT1); >>> + * *val = (long)(FIELD_GET(FPGA_TEMPERATURE, v) * 1000); >>> + * break; >>> + */ >>> + uint64_t v = ptr[2]; >>> + v &= (1 << 6) -1; >>> + v *= 1000; >>> + printf("Temperature %d\n", v); >>> + >>> + munmap(ptr, page_size); >>> + } >>> + if (close(fd)) >>> + perror("uio close:"); >>> + >>> + return errno; >>> +} >>> -- >>> 2.18.4