Re: [RFC] PCI: designware: missing *config* reg space

[Murali Karicheri <m-karicheri2@ti.com>]

On 05/10/2015 08:54 AM, Pratyush Anand wrote:
> On Tue, Apr 28, 2015 at 1:57 AM, Murali Karicheri <m-karicheri2@ti.com> wrote:
>> All,
>>
>> I would like to take action to resolve the following print message thrown by
>> PCI designware core driver when kernel boots up on Keystone.
>>
>> [    0.415778] keystone-pcie 21801000.pcie: missing *config* reg space
>>
>> As per DT documentation introduced by commit
>> 4dd964df36d0e548e1806ec2ec275b62d4dc46e8 "PCI: designware: Look for
>> configuration space in 'reg', not 'ranges'
>>
>> This is introduced to stop abusing the range property for defining resource
>> for config space. However if the device binding doesn't have
>> reg-name = "config" defined, this throws out an unnecessary log message
>> at boot which seems to me not right. AFAIK, reg-names is not mandatory.
>> config space address in Keystone case is defined using index. So for
>> keystone this needs to be fixed.
>>
>> I propose to add the following check in the designware code to address
>> this. Keystone uses an older version of the Designware IP and doesn't have
>> the ATU support. So va_cfg0_base and va_cfg1_base are already set up in
>> ks_dw_pcie_host_init() before calling dw_pcie_host_init() and points to the
>> remote config space address (both same for keystone). I think for other DW
>> drivers, these variables are NULL. So add a check and avoid this error
>> message for Keystone. Any comments?
>>
> or may be just following one liner should do the job for you.
>
> diff --git a/drivers/pci/host/pcie-designware.c
> b/drivers/pci/host/pcie-designware.c
> index 2e9f84fdd9ce..4ff5308f0cc6 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -371,7 +371,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
>                  addrp = of_get_address(np, index, NULL, NULL);
>                  pp->cfg0_mod_base = of_read_number(addrp, ns);
>                  pp->cfg1_mod_base = pp->cfg0_mod_base + pp->cfg0_size;
> -       } else {
> +       } else if (!pp->va_cfg0_base) {
>                  dev_err(pp->dev, "missing *config* reg space\n");
>          }
Yes. That will work. I will post a patch for this.

Murali
>
> ~Pratyush
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-- 
Murali Karicheri
Linux Kernel, Keystone