[PATCH] PCI: tegra: Fix building Tegra194 PCIe driver

[PATCH] PCI: tegra: Fix building Tegra194 PCIe driver

[Jon Hunter]

Commit 7f100744749e ("PCI: tegra: Add Tegra194 MCFG quirks for ECAM
errata") caused a couple build regressions for the Tegra194 PCIe driver
which are:

1. The Tegra194 PCIe driver can no longer be built as a module. This
   was caused by removing the Makefile entry to build the pcie-tegra.c
   based upon the CONFIG_PCIE_TEGRA194 option. Therefore, restore this
   so that we can build the driver as a module if ACPI support is not
   enabled in the kernel.
2. If CONFIG_PCIE_TEGRA194 is configured to build the driver as a
   module, at the same time that CONFIG_ACPI and CONFIG_PCI_QUIRKS are
   selected to build the driver into the kernel, then the necessary
   functions in the driver to probe and remove the device when booting
   with device-tree and not compiled into to the driver. This prevents
   the PCIe devices being probed when booting with device-tree. Fix this
   by using the IS_ENABLED() macro.

Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
---
 drivers/pci/controller/dwc/Makefile        | 1 +
 drivers/pci/controller/dwc/pcie-tegra194.c | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
index eca805c1a023..f0d1e2d8c022 100644
--- a/drivers/pci/controller/dwc/Makefile
+++ b/drivers/pci/controller/dwc/Makefile
@@ -32,6 +32,7 @@ obj-$(CONFIG_PCIE_UNIPHIER_EP) += pcie-uniphier-ep.o
 # depending on whether ACPI, the DT driver, or both are enabled.
 
 obj-$(CONFIG_PCIE_AL) += pcie-al.o
+obj-$(CONFIG_PCIE_TEGRA194) += pcie-tegra194.o
 obj-$(CONFIG_PCI_HISI) += pcie-hisi.o
 
 ifdef CONFIG_ACPI
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index b19775ab134e..8bda1485d0c2 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -409,7 +409,7 @@ const struct pci_ecam_ops tegra194_pcie_ops = {
 };
 #endif /* defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS) */
 
-#ifdef CONFIG_PCIE_TEGRA194
+#if IS_ENABLED(CONFIG_PCIE_TEGRA194)
 
 static inline struct tegra_pcie_dw *to_tegra_pcie(struct dw_pcie *pci)
 {
-- 
2.25.1

Re: [PATCH] PCI: tegra: Fix building Tegra194 PCIe driver

[Krzysztof Wilczyński]

Hi Jon,

> Commit 7f100744749e ("PCI: tegra: Add Tegra194 MCFG quirks for ECAM
> errata") caused a couple build regressions for the Tegra194 PCIe driver
> which are:
> 
> 1. The Tegra194 PCIe driver can no longer be built as a module. This
>    was caused by removing the Makefile entry to build the pcie-tegra.c
>    based upon the CONFIG_PCIE_TEGRA194 option. Therefore, restore this
>    so that we can build the driver as a module if ACPI support is not
>    enabled in the kernel.
> 2. If CONFIG_PCIE_TEGRA194 is configured to build the driver as a
>    module, at the same time that CONFIG_ACPI and CONFIG_PCI_QUIRKS are
>    selected to build the driver into the kernel, then the necessary
>    functions in the driver to probe and remove the device when booting
>    with device-tree and not compiled into to the driver. This prevents
>    the PCIe devices being probed when booting with device-tree. Fix this
>    by using the IS_ENABLED() macro.

Thank you for fixing this!  Much appreciated.

There are also few build time warnings related to these changes you
mention above, as per:

  drivers/pci/controller/dwc/pcie-tegra194.c:259:18: warning: ‘event_cntr_data_offset’ defined but not used [-Wunused-const-variable=]
  drivers/pci/controller/dwc/pcie-tegra194.c:250:18: warning: ‘event_cntr_ctrl_offset’ defined but not used [-Wunused-const-variable=]
  drivers/pci/controller/dwc/pcie-tegra194.c:243:27: warning: ‘pcie_gen_freq’ defined but not used [-Wunused-const-variable=]

We could bill two birds with one stone, so to speak, and move these
variables into the block behind the CONFIG_PCIE_TEGRA194 and
CONFIG_PCIEASPM guards respectively, so that these symbols are no longer
unused.

Also, since this change fixes and issue introduced in a different
commit, then it would be prudent to add the "Fixes:" tag.

Krzysztof

Re: [PATCH] PCI: tegra: Fix building Tegra194 PCIe driver

[Jon Hunter]

Hi Krzysztof,

On 19/05/2021 17:57, Krzysztof Wilczyński wrote:
> Hi Jon,
> 
>> Commit 7f100744749e ("PCI: tegra: Add Tegra194 MCFG quirks for ECAM
>> errata") caused a couple build regressions for the Tegra194 PCIe driver
>> which are:
>>
>> 1. The Tegra194 PCIe driver can no longer be built as a module. This
>>    was caused by removing the Makefile entry to build the pcie-tegra.c
>>    based upon the CONFIG_PCIE_TEGRA194 option. Therefore, restore this
>>    so that we can build the driver as a module if ACPI support is not
>>    enabled in the kernel.
>> 2. If CONFIG_PCIE_TEGRA194 is configured to build the driver as a
>>    module, at the same time that CONFIG_ACPI and CONFIG_PCI_QUIRKS are
>>    selected to build the driver into the kernel, then the necessary
>>    functions in the driver to probe and remove the device when booting
>>    with device-tree and not compiled into to the driver. This prevents
>>    the PCIe devices being probed when booting with device-tree. Fix this
>>    by using the IS_ENABLED() macro.
> 
> Thank you for fixing this!  Much appreciated.
> 
> There are also few build time warnings related to these changes you
> mention above, as per:
> 
>   drivers/pci/controller/dwc/pcie-tegra194.c:259:18: warning: ‘event_cntr_data_offset’ defined but not used [-Wunused-const-variable=]
>   drivers/pci/controller/dwc/pcie-tegra194.c:250:18: warning: ‘event_cntr_ctrl_offset’ defined but not used [-Wunused-const-variable=]
>   drivers/pci/controller/dwc/pcie-tegra194.c:243:27: warning: ‘pcie_gen_freq’ defined but not used [-Wunused-const-variable=]
> 
> We could bill two birds with one stone, so to speak, and move these
> variables into the block behind the CONFIG_PCIE_TEGRA194 and
> CONFIG_PCIEASPM guards respectively, so that these symbols are no longer
> unused.

Ah good to know. Yes I can incorporate into this change as well. Thanks
for letting me know.

> Also, since this change fixes and issue introduced in a different
> commit, then it would be prudent to add the "Fixes:" tag.

Yes it would. I had missed that, but will add.

Thanks!
Jon

-- 
nvpublic