Hi,

i have successfully run the GPMC in asynchronous mode for a while, but to 
get more stable and higher read bandwidth i have recently switched to the 
synchronous mode with burst-reads. This works well when doing reads and 
writes with memcpy in kernel space but i'am struggling to get it working 
with EDMA. I 'am using the exact same DMA configuration that i was using 
for the asynchronous mode but it shows a weird behavior. Apparently the 
EDMA tries to access the GPMC with burst of 32 x 16 bit words where the 
GPMC support a max 16 x 16 bit burst accesses. As a result reading data 
gives packet with 16 correct data followed by 16 constant value then 16 
correct data again. The CAM3 cape seems to be working well with burst reads 
and EDMA so i suspect that they are using a specific DMA configuration (or 
a specific DMA channel) but i just cannot figure it out. Any advice ?


Jonathan Piat

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