soc/amd/picasso: Split ops for internal and external PCIe GPP bridges

This change splits the device operations for internal and external PCIe
GPP bridges so that the external bridges use `pciexp_scan_bridge()`
instead of `pci_scan_bridge()`. `pciexp_scan_bridge()` is required for
external GPP bridges to enable ASPM on downstream devices if supported.

BUG=b:162352484
TEST=Verified on Trembyle:
$ lspci -s 1:00.0 -vvv | grep ASPM
LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L0s L1, Exit Latency L0s <4us, L1 <64u
      ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+
LnkCtl: ASPM L1 Enabled; RCB 64 bytes Disabled- CommClk
L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+ L1_PM_Substates+
L1SubCtl1: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1

Signed-off-by: Furquan Shaikh <furquan@google.com>
Change-Id: Ice2aa3e4758adccf7b0b89d4222fc65a40761153
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44016
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Peers <epeers@google.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

1 files changed, 20 insertions, 4 deletions

diff --git a/src/soc/amd/picasso/pcie_gpp.c b/src/soc/amd/picasso/pcie_gpp.c
index 73de80365d..96d33f2f1f 100644
--- a/src/soc/amd/picasso/pcie_gpp.c
+++ b/src/soc/amd/picasso/pcie_gpp.c
@@ -3,6 +3,7 @@
 #include <acpi/acpigen.h>
 #include <device/device.h>
 #include <device/pci.h>
+#include <device/pciexp.h>
 #include <device/pci_ids.h>
 #include <soc/pci_devs.h>
 #include <stdio.h>
@@ -36,7 +37,7 @@ static const char *pcie_gpp_acpi_name(const struct device *dev)
 	return NULL;
 }
 
-static struct device_operations pcie_gpp_ops = {
+static struct device_operations internal_pcie_gpp_ops = {
 	.read_resources		= pci_bus_read_resources,
 	.set_resources		= pci_dev_set_resources,
 	.enable_resources	= pci_bus_enable_resources,
@@ -47,14 +48,29 @@ static struct device_operations pcie_gpp_ops = {
 };
 
 static const unsigned short pci_device_ids[] = {
-	PCI_DEVICE_ID_AMD_FAM17H_PCIE_GPP,
 	PCI_DEVICE_ID_AMD_FAM17H_PCIE_GPP_BUSA,
 	PCI_DEVICE_ID_AMD_FAM17H_PCIE_GPP_BUSB,
 	0
 };
 
-static const struct pci_driver pcie_gpp_driver __pci_driver = {
-	.ops			= &pcie_gpp_ops,
+static const struct pci_driver internal_pcie_gpp_driver __pci_driver = {
+	.ops			= &internal_pcie_gpp_ops,
 	.vendor			= PCI_VENDOR_ID_AMD,
 	.devices		= pci_device_ids,
 };
+
+static struct device_operations external_pcie_gpp_ops = {
+	.read_resources		= pci_bus_read_resources,
+	.set_resources		= pci_dev_set_resources,
+	.enable_resources	= pci_bus_enable_resources,
+	.scan_bus		= pciexp_scan_bridge,
+	.reset_bus		= pci_bus_reset,
+	.acpi_name		= pcie_gpp_acpi_name,
+	.acpi_fill_ssdt		= acpi_device_write_pci_dev,
+};
+
+static const struct pci_driver external_pcie_gpp_driver __pci_driver = {
+	.ops			= &external_pcie_gpp_ops,
+	.vendor			= PCI_VENDOR_ID_AMD,
+	.device			= PCI_DEVICE_ID_AMD_FAM17H_PCIE_GPP,
+};