soc/intel/tigerlake: Add soc_get_cpu_rp_vw_idx() function

The PMC IPC method used to enable/disable PCIe clk sources uses the
LCAP PN field to distinguish PCH RPs. For CPU RPs, the PMC IPC
command expects the RP number to be its "virtual wire index"
instead. This new function returns this virtual wire index
for each of the CPU PCIe RPs.

BUG=b:197983574

Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Change-Id: I7aa14a634dcd90c4817009db970fb209ae02c63d
Reviewed-on: https://review.coreboot.org/c/coreboot/+/60179
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Tim Crawford <tcrawford@system76.com>
Reviewed-by: Cliff Huang <cliff.huang@intel.corp-partner.google.com>
Reviewed-by: Subrata Banik <subratabanik@google.com>

src/soc/intel/common/block/include/intelblocks/pcie_rp.h

@@ -121,4 +121,7 @@ enum pcie_rp_type {
 struct device; /* Not necessary to include all of device/device.h */
 enum pcie_rp_type soc_get_pcie_rp_type(const struct device *dev);
 
+/* Return the virtual wire index that represents CPU-side PCIe root ports */
+int soc_get_cpu_rp_vw_idx(const struct device *dev);
+
 #endif /* SOC_INTEL_COMMON_BLOCK_PCIE_RP_H */

src/soc/intel/tigerlake/pcie_rp.c

@@ -4,6 +4,8 @@
 #include <intelblocks/pcie_rp.h>
 #include <soc/pci_devs.h>
 
+#define CPU_CPIE_VW_IDX_BASE		24
+
 static const struct pcie_rp_group pch_lp_rp_groups[] = {
 	{ .slot = PCH_DEV_SLOT_PCIE,	.count = 8 },
 	{ .slot = PCH_DEV_SLOT_PCIE_1,	.count = 8 },
@@ -49,3 +51,22 @@ enum pcie_rp_type soc_get_pcie_rp_type(const struct device *dev)
 
 	return PCIE_RP_UNKNOWN;
 }
+
+int soc_get_cpu_rp_vw_idx(const struct device *dev)
+{
+	if (dev->path.type != DEVICE_PATH_PCI)
+		return -1;
+
+	switch (dev->path.pci.devfn) {
+	case SA_DEVFN_PEG1:
+		return CPU_CPIE_VW_IDX_BASE + 2;
+	case SA_DEVFN_PEG2:
+		return CPU_CPIE_VW_IDX_BASE + 1;
+	case SA_DEVFN_PEG3:
+		return CPU_CPIE_VW_IDX_BASE;
+	case SA_DEVFN_CPU_PCIE:
+		return CPU_CPIE_VW_IDX_BASE + 3;
+	default:
+		return -1;
+	}
+}