linux-kernel - Re: [PATCH 2/5] PCI: Extract link speed & width retrieval from pcie_get_minimum

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Date:   Mon, 14 Nov 2016 15:02:16 -0600
From:   Bjorn Helgaas <helgaas@...nel.org>
To:     Alex Williamson <alex.williamson@...hat.com>
Cc:     linux-pci@...r.kernel.org, bhelgaas@...gle.com,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/5] PCI: Extract link speed & width retrieval from
 pcie_get_minimum_link()

On Wed, Oct 26, 2016 at 12:01:22PM -0600, Alex Williamson wrote:
> Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
> ---
>  drivers/pci/pci.c   |   26 ++++++++++++++++++++------
>  include/linux/pci.h |    2 ++
>  2 files changed, 22 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index b901ee7..6d6cf89 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4729,6 +4729,25 @@ int pcie_set_mps(struct pci_dev *dev, int mps)
>  }
>  EXPORT_SYMBOL(pcie_set_mps);
>  
> +int pcie_get_link(struct pci_dev *dev, enum pci_bus_speed *speed,
> +		  enum pcie_link_width *width)

Seems like "pcie_get_link" is missing a word.  I know
pcie_get_minimum_link() exists already and is similar.

pcie_get_link_speed(), maybe?  I know it also gets the width, so maybe
there's a more inclusive term that would be better.

> +{
> +	int ret;
> +	u16 lnksta;
> +
> +	ret = pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta);
> +	if (ret)
> +		return ret;
> +
> +	if (speed)
> +		*speed = pcie_link_speed[lnksta & PCI_EXP_LNKSTA_CLS];
> +	if (width)
> +		*width = (lnksta & PCI_EXP_LNKSTA_NLW) >>
> +					PCI_EXP_LNKSTA_NLW_SHIFT;
> +
> +	return 0;
> +}
> +
>  /**
>   * pcie_get_minimum_link - determine minimum link settings of a PCI device
>   * @dev: PCI device to query
> @@ -4747,18 +4766,13 @@ int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed,
>  	*width = PCIE_LNK_WIDTH_UNKNOWN;
>  
>  	while (dev) {
> -		u16 lnksta;
>  		enum pci_bus_speed next_speed;
>  		enum pcie_link_width next_width;
>  
> -		ret = pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &lnksta);
> +		ret = pcie_get_link(dev, &next_speed, &next_width);
>  		if (ret)
>  			return ret;
>  
> -		next_speed = pcie_link_speed[lnksta & PCI_EXP_LNKSTA_CLS];
> -		next_width = (lnksta & PCI_EXP_LNKSTA_NLW) >>
> -			PCI_EXP_LNKSTA_NLW_SHIFT;
> -
>  		if (next_speed < *speed)
>  			*speed = next_speed;
>  
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index c3248d5..fbfbb40 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1026,6 +1026,8 @@ static inline int pci_is_managed(struct pci_dev *pdev)
>  int pcie_set_mps(struct pci_dev *dev, int mps);
>  int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed,
>  			  enum pcie_link_width *width);
> +int pcie_get_link(struct pci_dev *dev, enum pci_bus_speed *speed,
> +		  enum pcie_link_width *width);
>  int __pci_reset_function(struct pci_dev *dev);
>  int __pci_reset_function_locked(struct pci_dev *dev);
>  int pci_reset_function(struct pci_dev *dev);
> 
> --
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