Re: [PATCH] PCI: Apply _HPX link control for all supported pcie device

[Bjorn Helgaas]

On Thu, Nov 06, 2014 at 05:59:40PM -0800, Yinghai Lu wrote:
> With commit 6cd33649fa83 ("PCI: Add pci_configure_device() during enumeration")
> and following commits, we apply _HPX for pci devices.
> 
> that is called via pci_scan_slot
> 			==>pci_scan_single_device
> 				==>pci_device_add
> 					==>pci_configure_device
> 						==>program_hpp_type2
> and dev->subordinate is not allocated yet.
> 
> So that link control setup get skipped.
> 
> Acoording to ACPI spec, there is no requirement that need to be set to pcie
> root port or downstream port.
> 
> We could just change to pcie_cap_has_lnkctl to cover all pcie devices with
> link control cap.
> 
> Fixes: 6cd33649fa83 ("PCI: Add pci_configure_device() during enumeration")
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> 
> ---
>  drivers/pci/access.c |   13 -------------
>  drivers/pci/pci.h    |   13 +++++++++++++
>  drivers/pci/probe.c  |    2 +-
>  3 files changed, 14 insertions(+), 14 deletions(-)
> 
> Index: linux-2.6/drivers/pci/probe.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/probe.c
> +++ linux-2.6/drivers/pci/probe.c
> @@ -1323,7 +1323,7 @@ static void program_hpp_type2(struct pci
>  			~hpp->pci_exp_devctl_and, hpp->pci_exp_devctl_or);
>  
>  	/* Initialize Link Control Register */
> -	if (dev->subordinate)
> +	if (pcie_cap_has_lnkctl(dev))
>  		pcie_capability_clear_and_set_word(dev, PCI_EXP_LNKCTL,
>  			~hpp->pci_exp_lnkctl_and, hpp->pci_exp_lnkctl_or);

Nice catch!  It's much cleaner to do this based on pcie_cap_has_lnkctl().

> Index: linux-2.6/drivers/pci/access.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/access.c
> +++ linux-2.6/drivers/pci/access.c
> @@ -444,19 +444,6 @@ static inline int pcie_cap_version(const
>  	return pcie_caps_reg(dev) & PCI_EXP_FLAGS_VERS;
>  }
>  
> -static inline bool pcie_cap_has_lnkctl(const struct pci_dev *dev)
> -{
> -	int type = pci_pcie_type(dev);
> -
> -	return type == PCI_EXP_TYPE_ENDPOINT ||
> -	       type == PCI_EXP_TYPE_LEG_END ||
> -	       type == PCI_EXP_TYPE_ROOT_PORT ||
> -	       type == PCI_EXP_TYPE_UPSTREAM ||
> -	       type == PCI_EXP_TYPE_DOWNSTREAM ||
> -	       type == PCI_EXP_TYPE_PCI_BRIDGE ||
> -	       type == PCI_EXP_TYPE_PCIE_BRIDGE;
> -}
> -
>  static inline bool pcie_cap_has_sltctl(const struct pci_dev *dev)
>  {
>  	int type = pci_pcie_type(dev);
> Index: linux-2.6/drivers/pci/pci.h
> ===================================================================
> --- linux-2.6.orig/drivers/pci/pci.h
> +++ linux-2.6/drivers/pci/pci.h
> @@ -6,6 +6,19 @@
>  
>  extern const unsigned char pcie_link_speed[];
>  
> +static inline bool pcie_cap_has_lnkctl(const struct pci_dev *dev)
> +{
> +	int type = pci_pcie_type(dev);
> +
> +	return type == PCI_EXP_TYPE_ENDPOINT ||
> +	       type == PCI_EXP_TYPE_LEG_END ||
> +	       type == PCI_EXP_TYPE_ROOT_PORT ||
> +	       type == PCI_EXP_TYPE_UPSTREAM ||
> +	       type == PCI_EXP_TYPE_DOWNSTREAM ||
> +	       type == PCI_EXP_TYPE_PCI_BRIDGE ||
> +	       type == PCI_EXP_TYPE_PCIE_BRIDGE;
> +}

But I don't want to move pcie_cap_has_lnkctl() to pci.h and leave
pcie_cap_has_sltctl() and pcie_cap_has_rtctl() in access.c.  They're all
related, so I think they should stay together.

What if we left them in access.c, made them non-static, non-inline, and
just added prototypes to pci.h?  Or I guess we could add a prototype just
for pcie_cap_has_lnkctl(), since that's the only one we need so far.

Bjorn

> +
>  /* Functions internal to the PCI core code */
>  
>  int pci_create_sysfs_dev_files(struct pci_dev *pdev);
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