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, t...@redhat.com wrote:
>>> From: Tom Rix <t...@redhat.com>
>>>
>>> >From [PATCH 0/2] UIO support for dfl devices
>>> https://lore.kernel.org/linux-fpga/1602828151-24784-1-git-send-email-
>> yilun...@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 <t...@redhat.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
