ARM DMA Zones (coherent memory pool)

From: Tom St Denis
Date: Tue Jan 22 2013 - 07:36:04 EST


Hi all,

I was wondering if there was a proper way of instructing the init code (atomic_pool_init) for the DMA coherent subsystem to point to a fixed location instead of using alloc_pages()?

I ask because on our system (Zynq702/706 boards) DDR has a high latency (~25-30 cycles) whereas FPGA memory can be much quicker. What I'd like to do is create a 256Kbyte memory in FPGA BRAMs and then have the CPU point at it for the DMA zone.

Is that at all possible through a simple kernel cmdline or patch?

Tom
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/