On Fri, 30 Sep 2005 14:22:18 +0100 Alex Zeffertt <ajz at cambridgebroadband.com> wrote:
> Till now I have worked around this problem by calling > dcache_invalidate_range() and dcache_flush_range() before and after > accesses to these areas. I'm now considering changing to Kalle's > way of doing it. > > Are there any drawbacks to this approach? To answer my own question: yes there is a drawback. I've just done some performance tests on my driver. In the first test the driver uses invalidate/flush calls to keep the cache coherent. In the second test I just use Kalle's mod to setbat(). In the second test the perfomance of the driver is roughly 1/3 of the performance in the first test. What I really want is a way of asserting GBL whenever the CPM accesses ANY memory area other than DPRAM. Hm. Alex
