Mike Banon has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/30987 )
Change subject: mb/asus: Add Asus A88XM-E FM2+ with documentation ......................................................................
Patch Set 34:
Finally I tested this latest patchset 34 on my A88XM-E with A10-6700 installed, and for me it's the opposite regarding IOMMU: if I apply this patchset as is, I get " AMD-Vi: Can not reserve memory region 0-80000 for mmio. AMD-Vi: This is a BIOS bug. Please contact your hardware vendor " at the beginning of Linux Kernel 4.15 booting (Linux Mint 19.2 LiveUSB) and, a few seconds later, iommu_disable kernel panic.
However, with IOMMU enabled, same Linux kernel is booting perfectly! And I see this IOMMU device at lspci. My .config - https://pastebin.com/5xrX7eqf , cat ./src/mainboard/asus/a88xm-e/config_seabios ### ### SeaBIOS custom configuration for ASUS A88XM-E ### # CONFIG_MEGASAS is not set # CONFIG_NVME is not set #
Although csb_patcher.sh from CB:33509 has been applied, its' changes do not affect IOMMU function, so I assume that IOMMU should be working for you as well with a small change below:
diff --git a/src/mainboard/asus/a88xm-e/devicetree.cb b/src/mainboard/asus/a88xm-e/devicetree.cb index 501d0f9995..aa00a5654a 100644 --- a/src/mainboard/asus/a88xm-e/devicetree.cb +++ b/src/mainboard/asus/a88xm-e/devicetree.cb @@ -26,7 +26,7 @@ chip northbridge/amd/agesa/family15tn/root_complex
chip northbridge/amd/agesa/family15tn # PCI side of HT root complex device pci 0.0 on end # Root Complex - device pci 0.2 off end # IOMMU + device pci 0.2 on end # IOMMU device pci 1.0 on end # Internal Graphics device pci 1.1 on end # Internal Audio (iGPU) device pci 2.0 on end # PCIEX16