On Tue, Mar 26, 2013 at 06:17:57PM +0100, Michael Grzeschik wrote: > On Tue, Mar 26, 2013 at 07:06:19PM +0200, Felipe Balbi wrote: > > On Tue, Mar 26, 2013 at 05:58:37PM +0100, Michael Grzeschik wrote: > > > The udc uses an shared dma memory space between hard and software. This > > > memory layout is described in ci13xxx_qh and ci13xxx_td which are marked > > > with the attribute ((packed)). > > > > > > The compiler currently does not know about the alignment of the memory > > > layout, and will create strb and ldrb operations. > > > > > > The Datasheet of the synopsys core describes, that some operations on > > > the mapped memory need to be atomic double word operations. I.e. the > > > next pointer addressing in the qhead, as otherwise the hardware could > > > read wrong data and totally stuck. > > > > > > This patch adds the attribute ((aligned(4))) to the structures to tell > > > the compiler to use 32bit operations. It also adds an wmb() for the > > > prepared TD data before it gets enqueued into the qhead. > > > > > > Signed-off-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx> > > > > Cc stable ? > > Yes, will add when repost. can also add: Reviewed-by: Felipe Balbi <balbi@xxxxxx> -- balbi
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