On Sat, May 05, 2018 at 12:16:13AM +0530, Ganapatrao Kulkarni wrote: > On Thu, Apr 26, 2018 at 4:29 PM, Mark Rutland <mark.rutland@xxxxxxx> wrote: > > On Wed, Apr 25, 2018 at 02:30:47PM +0530, Ganapatrao Kulkarni wrote: > >> + * > >> + * L3 Tile and DMC channel selection is through SMC call > >> + * SMC call arguments, > >> + * x0 = THUNDERX2_SMC_CALL_ID (Vendor SMC call Id) > >> + * x1 = THUNDERX2_SMC_SET_CHANNEL (Id to set DMC/L3C channel) > >> + * x2 = Node id > > > > How do we map Linux node IDs to the firmware's view of node IDs? > > > > I don't believe the two are necessarily the same -- Linux's node IDs are > > a Linux-specific construct. > > both are same, it is numa node id from ACPI/firmware. I am very wary about assuming that the Linux nid will always be the same as the ACPI node id. For that to *potentially* be true, this driver should depend on CONFIG_NUMA, NUMA must not be disabled on the command line, etc, or the node id will always be NUMA_NO_NODE. I would be *much* happier if we had an explicit mapping somewhere to the ID the FW expects. > > It would be much nicer if we could pass something based on the MPIDR, > > which is a known HW construct, or if this implicitly affected the > > current node. > > IMO, node id is sufficient. I agree that *a* node ID is sufficient, I just don't think that we're guaranteed to have the specific node ID the FW wants. > > It would be vastly more sane for this to not be muxed at all. :/ > > i am helpless due to crappy hw design! I'm certainly not blaming you for this! :) I hope the HW designers don't make the same mistake in future, though... Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
