Re: [dpdk-dev] [PATCH v2] igb_uio: issue FLR during open and release of device file

["Tan, Jianfeng" <jianfeng.tan@intel.com>]

Hi Thotton,

> -----Original Message-----
> From: Shijith Thotton [mailto:shijith.thotton@caviumnetworks.com]
> Sent: Friday, July 7, 2017 7:14 PM
> To: dev@dpdk.org
> Cc: Yigit, Ferruh; Gregory Etelson; Thomas Monjalon; Stephen Hemminger;
> Tan, Jianfeng; Lu, Wenzhuo
> Subject: [PATCH v2] igb_uio: issue FLR during open and release of device file
> 
> Set UIO info device file operations open and release. Call pci reset
> function inside open and release to clear device state at start and end.
> Copied this behaviour from vfio_pci kernel module code. With this patch,
> it is not mandatory to issue FLR by PMD's during init and close.

I'm afraid this will not work for restarted DPDK process. In current probe(), we set up the I/O mem and I/O port; and those sys files are used by EAL IGB_UIO initialization code to map I/O mem and port. After reset in release(), we will lose those sys files in next open().

Thanks,
Jianfeng

> 
> Bus master enable and disable are added in open and release respectively
> to take care of device DMA.
> 
> Signed-off-by: Shijith Thotton <shijith.thotton@caviumnetworks.com>
> ---
> v2 changes:
>  - Replaced pci_try_reset_function with pci_reset_function as it is not
>    available in older kernel versions.
> 
> v1 changes:
>  - Added pci set master inside open and clear master inside release.
>  - Remove obvious comments.
> 
> RFC: http://dpdk.org/ml/archives/dev/2017-May/066917.html
> 
>  lib/librte_eal/linuxapp/igb_uio/igb_uio.c | 33
> +++++++++++++++++++++++++++++++
>  1 file changed, 33 insertions(+)
> 
> diff --git a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
> b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
> index b9d427c..07a19a3 100644
> --- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
> +++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
> @@ -170,6 +170,37 @@ struct rte_uio_pci_dev {
>  	return IRQ_HANDLED;
>  }
> 
> +/**
> + * This gets called while opening uio device file.
> + */
> +static int
> +igbuio_pci_open(struct uio_info *info, struct inode *inode)
> +{
> +	struct rte_uio_pci_dev *udev = info->priv;
> +	struct pci_dev *dev = udev->pdev;
> +
> +	pci_reset_function(dev);
> +
> +	/* set bus master, which was cleared by the reset function */
> +	pci_set_master(dev);
> +
> +	return 0;
> +}
> +
> +static int
> +igbuio_pci_release(struct uio_info *info, struct inode *inode)
> +{
> +	struct rte_uio_pci_dev *udev = info->priv;
> +	struct pci_dev *dev = udev->pdev;
> +
> +	/* stop the device from further DMA */
> +	pci_clear_master(dev);
> +
> +	pci_reset_function(dev);
> +
> +	return 0;
> +}
> +
>  #ifdef CONFIG_XEN_DOM0
>  static int
>  igbuio_dom0_mmap_phys(struct uio_info *info, struct vm_area_struct
> *vma)
> @@ -372,6 +403,8 @@ struct rte_uio_pci_dev {
>  	udev->info.version = "0.1";
>  	udev->info.handler = igbuio_pci_irqhandler;
>  	udev->info.irqcontrol = igbuio_pci_irqcontrol;
> +	udev->info.open = igbuio_pci_open;
> +	udev->info.release = igbuio_pci_release;
>  #ifdef CONFIG_XEN_DOM0
>  	/* check if the driver run on Xen Dom0 */
>  	if (xen_initial_domain())
> --
> 1.8.3.1