soc/amd/common/data_fabric: read PCI bus decoding from DF registers
The data fabric also controls which PCI bus numbers get decoded to the
PCI root. In order for the resource allocator to know how the hardware
is configured, read the corresponding data fabric registers to get the
information that then gets passed to the allocator.
Picasso, Cezanne, Mendocino and Rembrandt only support one PCI segment
with 256 buses while the Phoenix and Glinda data fabric hardware has
support for more PCI segments. Due to this change, the register layout
is different and incompatible between those two, so introduce the
SOC_AMD_COMMON_BLOCK_DATA_FABRIC_MULTI_PCI_SEGMENT Kconfig option for a
SoC to specify which implementation is needed. At the moment, coreboot
doesn't have support for multiple PCI segments and the code doesn't
support PCI segments other than segment 0.
On Picasso the PCI bus number limit read back from the data fabric
register is 255 even though CONFIG_ECAM_MMCONF_BUS_NUMBER is set to 64,
so also make sure that the bus and limit returned by
data_fabric_get_pci_bus_numbers is within the expected limits.
TEST=PCI bus allocation still works on Mandolin (Picasso) and Birman
(Phoenix). Picasso has 64 PCI buses. coreboot puts this info into the
resource producer in _SB\PCI0\_CRS which the Linux kernel reads:
* coreboot: PCI0 _CRS: adding busses [0-3f]
* Linux: pci_bus 0000:00: root bus resource [bus 00-3f]
This matches the information in the ACPI MCFG table.
Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: Ide5fa9b3e95cfd59232048910cc8feacb6dbdb94
Reviewed-on: https://review.coreboot.org/c/coreboot/+/77080
Reviewed-by: Martin L Roth <gaumless@gmail.com>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/amd/common/block/data_fabric/domain.c b/src/soc/amd/common/block/data_fabric/domain.c
index 88b1160..d693879 100644
--- a/src/soc/amd/common/block/data_fabric/domain.c
+++ b/src/soc/amd/common/block/data_fabric/domain.c
@@ -16,10 +16,15 @@
{
uint8_t bus, limit;
- /* TODO: Systems with more than one PCI root need to read the data fabric registers to
- see which PCI bus numbers get decoded to which PCI root. */
- bus = 0;
- limit = CONFIG_ECAM_MMCONF_BUS_NUMBER - 1;
+ if (data_fabric_get_pci_bus_numbers(domain, &bus, &limit) != CB_SUCCESS) {
+ printk(BIOS_ERR, "No PCI bus numbers decoded to PCI root.\n");
+ return;
+ }
+
+ /* TODO: Check if bus >= CONFIG_ECAM_MMCONF_BUS_NUMBER and return in that case */
+
+ /* Make sure to not report more than CONFIG_ECAM_MMCONF_BUS_NUMBER PCI buses */
+ limit = MIN(limit, CONFIG_ECAM_MMCONF_BUS_NUMBER - 1);
/* Set bus first number of PCI root */
domain->link_list->secondary = bus;