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.grzesc...@pengutronix.de>
Cc stable ? -- balbi
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