Change Details

This fixes e.g. amdgpu operation on the NXP Layerscape LX2160A SoC (powering the SolidRun HoneyComb LX2K workstation) which has a Translation Offset in ACPI for below-4G PCI addresses. Tested by: Dan Kotowski <dan.kotowski@a9development.com>

This fixes e.g. amdgpu operation on the NXP Layerscape LX2160A SoC (powering the SolidRun HoneyComb LX2K workstation) which has a Translation Offset in ACPI for below-4G PCI addresses. --- See https://github.com/freebsd/drm-kmod/issues/84 for our long debugging session :) tl;dr due to how Linux drivers are written, LinuxKPI requires raw physical memory addresses. In D21096 / rS350570, a `BUS_TRANSLATE_RESOURCE` method was introduced to allow LinuxKPI to get physical addresses in `pci_resource_start`, this was done for PowerPC and implemented in `ofw_pci`. When translation was implemented in `pci_host_generic` in r10:372c142b4fc almost a year later, this method was not implemented — instead a local `static` function was added for a similar purpose. And that's why GPUs were mysteriously broken on the LX2K, instead of talking to the GPU's configuration register area, the driver was talking to something else and receiving all zeros. --- BIKESHEDDING TIME: Obviously this first version of the patch is not beautiful. Having a second wrapper function that throws out the `end` is… meh :/ Would it be fine to just convert to the start-only API, and recalculate `end` in callers based on `start` and the size? (And if not, any suggestions on naming these, any other changes?)

This fixes e.g. amdgpu operation on the NXP Layerscape LX2160A SoC (powering the SolidRun HoneyComb LX2K workstation) which has a Translation Offset in ACPI for below-4G PCI addresses. --- See https://github.com/freebsd/drm-kmod/issues/84 for our long debugging session :) tl;dr due to how Linux drivers are written, LinuxKPI requires raw physical memory addresses. (powering the SolidRun HoneyComb LX2K workstation) which has aIn D21096 / rS350570, a `BUS_TRANSLATE_RESOURCE` method was introduced to allow LinuxKPI to get physical addresses in `pci_resource_start`, this was done for PowerPC and implemented in `ofw_pci`. Translation Offset in ACPI for below-4G PCI addresseWhen translation was implemented in `pci_host_generic` in r10:372c142b4fc almost a year later, this method was not implemented — instead a local `static` function was added for a similar purpose. And that's why GPUs were mysteriously broken on the LX2K, instead of talking to the GPU's configuration register area, the driver was talking to something else and receiving all zeros. Tested by: Dan Kotowski <dan.kotowski@a9development.com>--- BIKESHEDDING TIME: Obviously this first version of the patch is not beautiful. Having a second wrapper function that throws out the `end` is… meh :/ Would it be fine to just convert to the start-only API, and recalculate `end` in callers based on `start` and the size? (And if not, any suggestions on naming these, any other changes?)