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Date: Mon, 7 Dec 2020 11:49:51 +0800
From: Xu Yilun <yilun.xu@...el.com>
To: trix@...hat.com
Cc: gregkh@...uxfoundation.org, hao.wu@...el.com, mdf@...nel.org,
linux-kernel@...r.kernel.org, linux-fpga@...r.kernel.org
Subject: Re: [RFC] fpga: dfl: a prototype uio driver
On Sun, Dec 06, 2020 at 01:55:54PM -0800, trix@...hat.com wrote:
> From: Tom Rix <trix@...hat.com>
>
> >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.
Thanks,
Yilun
>
> Signed-off-by: Tom Rix <trix@...hat.com>
> ---
> 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 <linux/module.h>
> +#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 <linux/platform_device.h>
> #include <linux/slab.h>
> #include <linux/uuid.h>
> +#include <linux/uio_driver.h>
> #include <linux/fpga/fpga-region.h>
>
> /* 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 <stdlib.h>
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <sys/mman.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +#include <errno.h>
> +#include <stdint.h>
> +
> +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
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