On 04/21/2016 06:08 AM, Tomasz Nowicki wrote:
On 21.04.2016 11:36, Arnd Bergmann wrote:
On Thursday 21 April 2016 11:28:15 Tomasz Nowicki wrote:
On 19.04.2016 15:06, Arnd Bergmann wrote:
On Monday 18 April 2016 21:31:54 Tomasz Nowicki wrote:
Basically the whole content of pci-thunder-ecam.c and pci-thunder-pem.c.
pci-thunder-ecam.c contains config space accessors. Similar for pci-thunder-pem.c but it also has extra init call (it is now called thunder_pem_init) which finds and maps related registers.
They seem to do much more than just override the accessors, they actually change the contents of the config space as well. Is that really necessary on ACPI based systems as well?
Yes, the pci-thunder-ecam.c accessors are meant to emulate config space capabilities. They are necessary to synthesize EA capabilities (fixed PCI BARs), it wont work without this, for ACPI boot as well.
Why is that? I thought the BARs never get reassigned when using ACPI, so I'm surprised it's actually needed. Maybe I misunderstood what you mean by fixed PCI BARs.
Yes, I meant something else. ThunderX has non-programmable PCI BAR addresses. So it uses PCI EA (Extended allocation) capabilities to get know PCI BARs addresses. But the early implementation (pass1.x) misses EA capabilities hence we need to emulate it in config space accessors.
Aside: In case it's helpful, at least one enterprise vendor I know of is only supporting later silicon as a result of this. So IMO there's no need to worry about this issue on the early preproduction chips.