[PATCH] drivers/misc/cxl: Avoid unnecessary error message

[Andrew Donnellan]

On 31/01/17 14:43, Gavin Shan wrote:
> The following error message was observed. It's complaining M32
> memory window is missed on virtual PHB, which is a bit confusing.
> The problem is the memory windows are never updated from its
> device-tree node.
>
>    PCI: Memory resource 0 not set for host bridge \
>    /pciex at 3fffe40000000/pci at 0/device at 0
>
> This avoids the unnecessary error message by updating the PHB's
> memory windows with pci_process_bridge_OF_ranges(). The function
> is exported as well.
>
> Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>

I talked this over with Gavin in person today.

We don't set a memory window on the vPHB or its devices because it's not 
necessary.

The effect of this patch is to copy the memory resources from the *real* 
PHB to the vPHB, as given through the device tree. It shouldn't have any 
practical effect other than squashing this message.


> ---
>  arch/powerpc/kernel/pci-common.c | 1 +
>  drivers/misc/cxl/vphb.c          | 9 +++++++++
>  2 files changed, 10 insertions(+)
>
> diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
> index 74bec54..b5ffd8a 100644
> --- a/arch/powerpc/kernel/pci-common.c
> +++ b/arch/powerpc/kernel/pci-common.c
> @@ -824,6 +824,7 @@ void pci_process_bridge_OF_ranges(struct pci_controller *hose,
>  		}
>  	}
>  }
> +EXPORT_SYMBOL_GPL(pci_process_bridge_OF_ranges);
>
>  /* Decide whether to display the domain number in /proc */
>  int pci_proc_domain(struct pci_bus *bus)
> diff --git a/drivers/misc/cxl/vphb.c b/drivers/misc/cxl/vphb.c
> index 3519ace..8382761 100644
> --- a/drivers/misc/cxl/vphb.c
> +++ b/drivers/misc/cxl/vphb.c
> @@ -215,6 +215,15 @@ int cxl_pci_vphb_add(struct cxl_afu *afu)
>  	if (!phb)
>  		return -ENODEV;
>
> +	/* Parse IO and memory ranges */
> +	if (dev_is_pci(parent)) {

Is this ever going to be false?

> +		struct pci_dev *pdev;

I think we tend to keep declarations up at the top of the function?

> +
> +		pdev = to_pci_dev(parent);
> +		vphb_dn = pnv_pci_get_phb_node(pdev);
> +		pci_process_bridge_OF_ranges(phb, vphb_dn, false);
> +	}
> +
>  	/* Setup parent in sysfs */
>  	phb->parent = parent;
>
>

-- 
Andrew Donnellan              OzLabs, ADL Canberra
andrew.donnellan at au1.ibm.com  IBM Australia Limited