soc/intel/tigerlake: Define soc_get_pcie_rp_type

In order to distinguish PCH from CPU PCIe RPs, define the
soc_get_pcie_rp_type function for Tiger Lake.

BUG=b:197983574

Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Change-Id: Ic3f7d3f2fc12ae2b53604cd8f8b694a7674c3620
Reviewed-on: https://review.coreboot.org/c/coreboot/+/59853
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@mailbox.org>
Reviewed-by: Subrata Banik <subrata.banik@intel.com>

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

@@ -117,4 +117,8 @@ enum pcie_rp_type {
 	PCIE_RP_PCH,
 };
 
+/* For PCIe RTD3 support, each SoC that uses it must implement this function. */
+struct device; /* Not necessary to include all of device/device.h */
+enum pcie_rp_type soc_get_pcie_rp_type(const struct device *dev);
+
 #endif /* SOC_INTEL_COMMON_BLOCK_PCIE_RP_H */

src/soc/intel/tigerlake/Makefile.inc

@@ -34,6 +34,7 @@ ramstage-y += lockdown.c
 ramstage-y += lpm.c
 ramstage-y += me.c
 ramstage-y += p2sb.c
+ramstage-y += pcie_rp.c
 ramstage-y += pmc.c
 ramstage-y += reset.c
 ramstage-y += soundwire.c

src/soc/intel/tigerlake/pcie_rp.c

@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <device/device.h>
+#include <intelblocks/pcie_rp.h>
+#include <soc/pci_devs.h>
+
+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 },
+	{ .slot = PCH_DEV_SLOT_PCIE_2,	.count = 4 },
+	{ 0 }
+};
+
+static const struct pcie_rp_group cpu_rp_groups[] = {
+	{ .slot = SA_DEV_SLOT_PEG,	.start = 0, .count = 3 },
+	{ .slot = SA_DEV_SLOT_CPU_PCIE,	.start = 0, .count = 1 },
+	{ 0 }
+};
+
+static bool is_part_of_group(const struct device *dev,
+			     const struct pcie_rp_group *groups)
+{
+	if (dev->path.type != DEVICE_PATH_PCI)
+		return false;
+
+	const unsigned int slot_to_find = PCI_SLOT(dev->path.pci.devfn);
+	const unsigned int fn_to_find = PCI_FUNC(dev->path.pci.devfn);
+	const struct pcie_rp_group *group;
+	unsigned int i;
+	unsigned int fn;
+
+	for (group = groups; group->count; ++group) {
+		for (i = 0, fn = rp_start_fn(group); i < group->count; i++, fn++) {
+			if (slot_to_find == group->slot && fn_to_find == fn)
+				return true;
+		}
+	}
+
+	return false;
+}
+
+enum pcie_rp_type soc_get_pcie_rp_type(const struct device *dev)
+{
+	if (is_part_of_group(dev, pch_lp_rp_groups))
+		return PCIE_RP_PCH;
+
+	if (is_part_of_group(dev, cpu_rp_groups))
+		return PCIE_RP_CPU;
+
+	return PCIE_RP_UNKNOWN;
+}