Re: [PATCH V2] PCI: tegra: Fix building Tegra194 PCIe driver

["Krzysztof Wilczyński" <kw@linux.com>]

Hi Jon,

> Commit 7f100744749e ("PCI: tegra: Add Tegra194 MCFG quirks for ECAM
> errata") caused a few 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.
> 3. The below build warnings to be seen with particular kernel
>    configurations. Fix these by adding the necessary guards around these
>    variable definitions.
> 
>   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=]
> 
> Fixes: 7f100744749e ("PCI: tegra: Add Tegra194 MCFG quirks for ECAM errata")

Thank you for fixing this!  Much appreciated!

[...]
> +#if IS_ENABLED(CONFIG_PCIE_TEGRA194)
>  static const unsigned int pcie_gen_freq[] = {
>  	GEN1_CORE_CLK_FREQ,
>  	GEN2_CORE_CLK_FREQ,
>  	GEN3_CORE_CLK_FREQ,
>  	GEN4_CORE_CLK_FREQ
>  };
> +#endif
>  
> +#if defined(CONFIG_PCIEASPM)
>  static const u32 event_cntr_ctrl_offset[] = {
>  	0x1d8,
>  	0x1a8,
> @@ -264,6 +267,7 @@ static const u32 event_cntr_data_offset[] = {
>  	0x1c8,
>  	0x1dc
>  };
> +#endif

A small note about the above - I believe Bjorn might prefer if we move
these two into the existing blocks, rather than wrapping both as done
here, so that things are grouped together.  Albeit, I leave it to Bjorn
to give us feedback on his preferred style.

Reviewed-by: Krzysztof Wilczyński <kw@linux.com>

Krzysztof