PCI support for SOC_MT7621

PCI support for SOC_MT7621

[Sergio Paracuellos]

Hi all,

I have a concern about commit:

c4d48cf5e2f0 ("MIPS: ralink: deactivate PCI support for SOC_MT7621")

This commit make a regression for my kernel configuration for gnubee
board which is mt7621 SOC based and also has PCI. With this applied
PCI_DRIVERS_GENERIC is not selectable anymore and it becomes into a
PCI_DRIVERS_LEGACY configuration making impossible to compile
mt7621-pci driver for this board.

I think this should be reverted. Am I missing something here?

Thanks in advance for your time.

Best regards,
    Sergio Paracuellos

Re: PCI support for SOC_MT7621

[NeilBrown]

[-- Attachment #1: Type: text/plain, Size: 876 bytes --]

On Wed, Oct 16 2019, Sergio Paracuellos wrote:

> Hi all,
>
> I have a concern about commit:
>
> c4d48cf5e2f0 ("MIPS: ralink: deactivate PCI support for SOC_MT7621")
>
> This commit make a regression for my kernel configuration for gnubee
> board which is mt7621 SOC based and also has PCI. With this applied
> PCI_DRIVERS_GENERIC is not selectable anymore and it becomes into a
> PCI_DRIVERS_LEGACY configuration making impossible to compile
> mt7621-pci driver for this board.
>
> I think this should be reverted. Am I missing something here?

The commit reports a build error without the patch, and we don't want
that.
Maybe change the
  select HAVE_PCI
to
  select HAVE_PCI if STAGING
or
  select HAVE_PCI if PCI_MT7621

Hauke: do either of those fix your compile error?

Thanks,
NeilBrown


>
> Thanks in advance for your time.
>
> Best regards,
>     Sergio Paracuellos

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]

Re: PCI support for SOC_MT7621

[Sergio Paracuellos]

Hi Neil,

On Wed, Oct 16, 2019 at 11:57 PM NeilBrown <neil@brown.name> wrote:
>
> On Wed, Oct 16 2019, Sergio Paracuellos wrote:
>
> > Hi all,
> >
> > I have a concern about commit:
> >
> > c4d48cf5e2f0 ("MIPS: ralink: deactivate PCI support for SOC_MT7621")
> >
> > This commit make a regression for my kernel configuration for gnubee
> > board which is mt7621 SOC based and also has PCI. With this applied
> > PCI_DRIVERS_GENERIC is not selectable anymore and it becomes into a
> > PCI_DRIVERS_LEGACY configuration making impossible to compile
> > mt7621-pci driver for this board.
> >
> > I think this should be reverted. Am I missing something here?
>
> The commit reports a build error without the patch, and we don't want
> that.

I didn't understand properly the commit message. Yes, of course we
don't want a build
fail :).

> Maybe change the
>   select HAVE_PCI
> to
>   select HAVE_PCI if STAGING
> or
>   select HAVE_PCI if PCI_MT7621

I think the second one could be more accurate in this case.

>
> Hauke: do either of those fix your compile error?
>

If so, I don't have any problem to send a patch with this fixed if you
are busy. Just let me know.

> Thanks,
> NeilBrown

Best regards,
    Sergio Paracuellos
>
>
> >
> > Thanks in advance for your time.
> >
> > Best regards,
> >     Sergio Paracuellos

Re: PCI support for SOC_MT7621

[Sergio Paracuellos]

On Thu, Oct 17, 2019 at 8:12 AM Sergio Paracuellos
<sergio.paracuellos@gmail.com> wrote:
>
> Hi Neil,
>
> On Wed, Oct 16, 2019 at 11:57 PM NeilBrown <neil@brown.name> wrote:
> >
> > On Wed, Oct 16 2019, Sergio Paracuellos wrote:
> >
> > > Hi all,
> > >
> > > I have a concern about commit:
> > >
> > > c4d48cf5e2f0 ("MIPS: ralink: deactivate PCI support for SOC_MT7621")
> > >
> > > This commit make a regression for my kernel configuration for gnubee
> > > board which is mt7621 SOC based and also has PCI. With this applied
> > > PCI_DRIVERS_GENERIC is not selectable anymore and it becomes into a
> > > PCI_DRIVERS_LEGACY configuration making impossible to compile
> > > mt7621-pci driver for this board.
> > >
> > > I think this should be reverted. Am I missing something here?
> >
> > The commit reports a build error without the patch, and we don't want
> > that.
>
> I didn't understand properly the commit message. Yes, of course we
> don't want a build
> fail :).
>
> > Maybe change the
> >   select HAVE_PCI
> > to
> >   select HAVE_PCI if STAGING
> > or
> >   select HAVE_PCI if PCI_MT7621
>
> I think the second one could be more accurate in this case.

Actually I tested this two changes with my current configuration.
PCI_MT7621 depends on PCI so the second one gets into a recursive
dependency problem. We can skip depends on PCI and only select
PCI_DRIVERS_GENERIC in mt7621_pci Kconfig file to avoid this. The
following change works,  but I don't know if this is the correct thing
to do:

$ git diff arch/mips/ralink/Kconfig drivers/staging/mt7621-pci/Kconfig
diff --git a/arch/mips/ralink/Kconfig b/arch/mips/ralink/Kconfig
index 1434fa60f3db..94e9ce994494 100644
--- a/arch/mips/ralink/Kconfig
+++ b/arch/mips/ralink/Kconfig
@@ -51,6 +51,7 @@ choice
                select MIPS_GIC
                select COMMON_CLK
                select CLKSRC_MIPS_GIC
+               select HAVE_PCI if PCI_MT7621
 endchoice

 choice
diff --git a/drivers/staging/mt7621-pci/Kconfig
b/drivers/staging/mt7621-pci/Kconfig
index af928b75a940..ce58042f2f21 100644
--- a/drivers/staging/mt7621-pci/Kconfig
+++ b/drivers/staging/mt7621-pci/Kconfig
@@ -2,7 +2,6 @@
 config PCI_MT7621
        tristate "MediaTek MT7621 PCI Controller"
        depends on RALINK
-       depends on PCI
        select PCI_DRIVERS_GENERIC
        help
          This selects a driver for the MediaTek MT7621 PCI Controller.

In the other hand, the "select HAVE_PCI if STAGING" one works as it is.

Thanks,
    Sergio Paracuellos
>
> >
> > Hauke: do either of those fix your compile error?
> >
>
> If so, I don't have any problem to send a patch with this fixed if you
> are busy. Just let me know.
>
> > Thanks,
> > NeilBrown
>
> Best regards,
>     Sergio Paracuellos
> >
> >
> > >
> > > Thanks in advance for your time.
> > >
> > > Best regards,
> > >     Sergio Paracuellos

[PATCH] MIPS: ralink: enable PCI support only if driver for mt7621 SoC is selected

[Sergio Paracuellos]

Some versions of SoC MT7621 have three PCI express hosts. Some boards
make use of those PCI through the staging driver mt7621-pci. Recently
PCI support has been removed from MT7621 Soc kernel configuration due
to a build error. This makes imposible to compile staging driver and
produces a regression for gnubee based boards. Enable support for PCI
again but enable it only if staging mt7621-pci driver is selected.

Fixes: c4d48cf5e2f0 ("MIPS: ralink: deactivate PCI support for SOC_MT7621")

Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: ralf@linux-mips.org
Cc: jhogan@kernel.org
Cc: john@phrozen.org
Cc: NeilBrown <neil@brown.name>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-mips@vger.kernel.org
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
---
 arch/mips/ralink/Kconfig           | 1 +
 drivers/staging/mt7621-pci/Kconfig | 1 -
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/ralink/Kconfig b/arch/mips/ralink/Kconfig
index 1434fa60f3db..94e9ce994494 100644
--- a/arch/mips/ralink/Kconfig
+++ b/arch/mips/ralink/Kconfig
@@ -51,6 +51,7 @@ choice
 		select MIPS_GIC
 		select COMMON_CLK
 		select CLKSRC_MIPS_GIC
+		select HAVE_PCI if PCI_MT7621
 endchoice
 
 choice
diff --git a/drivers/staging/mt7621-pci/Kconfig b/drivers/staging/mt7621-pci/Kconfig
index af928b75a940..ce58042f2f21 100644
--- a/drivers/staging/mt7621-pci/Kconfig
+++ b/drivers/staging/mt7621-pci/Kconfig
@@ -2,7 +2,6 @@
 config PCI_MT7621
 	tristate "MediaTek MT7621 PCI Controller"
 	depends on RALINK
-	depends on PCI
 	select PCI_DRIVERS_GENERIC
 	help
 	  This selects a driver for the MediaTek MT7621 PCI Controller.
-- 
2.19.1