Hi Michal, On Fri, Mar 16, 2012 at 4:57 PM, Michal Simek <monstr@xxxxxxxxx> wrote: > In previous version I had carverout first which means that code was copyied > to physical address 0x0 and then vrigns were allocated. Current code > allocate vring first and then RTOS is not able to run from zero address. In general, depending on specific allocation ordering is error prone and you shouldn't do it. For a given device, we treat memory allocated with dma_alloc_coherent() as homogeneous. We care about its utilization and alignments of allocations rather than their specific location in the total region. If that's not the case, and there's special memory you want assigned with a specific purpose, than it's recommended to let the code make sure it happens explicitly, and not rely on implicit order of allocation. Today there's no way to assign several memory regions with a specific device, but a reasonable workaround that's being used is creating several sub-devices with the special memory, and then looking them up with stuff like device_for_each_child() or device_find_child(). About your specific issue: the current allocation scheme was chosen for simplicity, but I do plan to change it back by postponing the vring dma allocation until a remote processor is really powered on. It's not a lot of memory, but this way we'd only allocate it when really needed (so if it's CMA, others could use it). IOW: you can probably just wait a bit until this patch is ready and take it into your tree. It will most likely bring back the behavior you need :) Ohad. -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
