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

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

[Murali Karicheri]

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?


--- a/drivers/pci/host/pcie-designware.c
+++ b/drivers/pci/host/pcie-designware.c
@@ -348,7 +348,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
         struct platform_device *pdev = to_platform_device(pp->dev);
         struct of_pci_range range;
         struct of_pci_range_parser parser;
-       struct resource *cfg_res;
+       struct resource *cfg_res = NULL;
         u32 val, na, ns;
         const __be32 *addrp;
         int i, index, ret;
@@ -359,7 +359,11 @@ int dw_pcie_host_init(struct pcie_port *pp)
         of_property_read_u32(np, "#address-cells", &na);
         ns = of_n_size_cells(np);

-       cfg_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, 
"config");
+       if (!pp->va_cfg0_base && !pp->va_cfg0_base)
+               cfg_res = platform_get_resource_byname(pdev,
+                                                      IORESOURCE_MEM,
+                                                      "config");
+
         if (cfg_res) {
                 pp->cfg0_size = resource_size(cfg_res)/2;
                 pp->cfg1_size = resource_size(cfg_res)/2;
@@ -372,7 +376,8 @@ int dw_pcie_host_init(struct pcie_port *pp)
                 pp->cfg0_mod_base = of_read_number(addrp, ns);
                 pp->cfg1_mod_base = pp->cfg0_mod_base + pp->cfg0_size;
         } else {
-               dev_err(pp->dev, "missing *config* reg space\n");
+               if (!pp->va_cfg0_base && !pp->va_cfg1_base)
+                       dev_err(pp->dev, "missing *config* reg space\n");
         }



-- 
Murali Karicheri
Linux Kernel, Texas Instruments

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

[Pratyush Anand]

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");
        }


~Pratyush

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

[Murali Karicheri]

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