1Some notes about the working of the atomisp drivers (learned while working 2on cleaning it up). 3 4The atomisp seems to be a generic DSP(ISP) like processor without a fixed 5pipeline. It does not have its own memory, but instead uses main memory. 6The ISP has its own address-space and main memory needs to be mapped into 7its address space through the ISP's MMU. 8 9Memory is allocated by the hmm code. hmm_alloc() returns an ISP virtual 10address. The hmm code keeps a list of all allocations and when necessary 11the hmm code finds the backing hmm-buffer-object (hmm_bo) by looking 12up the hmm_bo based on the ISP virtual address. 13 14The actual processing pipeline is made by loading one or more programs, 15called binaries. The shisp_240??0_v21.bin firmware file contains many 16different binaries. Binaries are picked by filling a ia_css_binary_descr 17struct with various input and output parameters and then calling 18ia_css_binary_find(). Some binaries support creating multiple outputs 19(preview + video frame?) at the same time. 20 21For example for the /dev/video0 preview node load_preview_binaries() 22from atomisp/pci/sh_css.c is called and then loads a preview and 23optionally a scalar binary. Note when digital zoom is disabled 24(it is enabled by default) only the preview binary is loaded. 25So in this case a single binary handles the entire pipeline. 26 27Since getting a picture requires multiple processing steps, 28this means that unlike in fixed pipelines the soft pipelines 29on the ISP can do multiple processing steps in a single pipeline 30element (in a single binary). 31