Benjamin Herrenschmidt wrote: > Oh and, don't do the set_dma_mask() in sbp2, it has nothing to do there. > It should be in the ohci1394 driver.
That's not quite right. OHCI-1394 implementations can go beyond 4GB bus address space. (Although I don't know if there are such implementations available. At least there are two implementations which can set the so-called Physical Range bigger than 4GB.) Sbp2 however requires that everything which it DMA-maps resides in the Physical Range of the controller. This way the CPU is not involved in most of the data transfers. The OHCI-1394 controller acts as bus bridge between IEEE 1394 bus and local bus, with a 1:1 mapping of IEEE 1394 bus addresses to and from local bus addresses --- but not in the whole 48 bits white IEEE 1394 bus address range, only in the implementation-dependent Physical Range. The minimum Physical Range that all OHCI-1394 implementations guarantee is 4GB. I could actually have set a bigger mask in sbp2 when the controller supports a programmable bigger range. So that's the story why that dma_set_mask went into sbp2: Sbp2 wants mappings in a _subset_ of the OHCI-1394 controllers DMA range. Anyway. For now I will simply go with what 2.6.23-rc has and what 2.6.21 had: No dma_set_mask anywhere in the 1394 subsystem. We can revisit this whenever an actual need arises. -- Stefan Richter -=====-=-=== =--- --==- http://arcgraph.de/sr/ _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
