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

[Jon Hunter <jonathanh@nvidia.com>]

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")
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
---
 drivers/pci/controller/dwc/Makefile        | 1 +
 drivers/pci/controller/dwc/pcie-tegra194.c | 6 +++++-
 2 files changed, 6 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..ae70e53a7826 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -240,13 +240,16 @@
 #define EP_STATE_DISABLED	0
 #define EP_STATE_ENABLED	1
 
+#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
 
 struct tegra_pcie_dw {
 	struct device *dev;
@@ -409,7 +413,7 @@ 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