• Afzal Mohammed's avatar
    dfu: ram support · a9479f04
    Afzal Mohammed authored
    DFU spec mentions it as a method to upgrade firmware (software stored
    in writable non-volatile memory). It also says other potential uses of
    DFU is beyond scope of the spec.
    
    Here such a beyond the scope use is being attempted - directly pumping
    binary images from host via USB to RAM. This facility is a developer
    centric one in that it gives advantage over upgrading non-volatile
    memory for testing new images every time during development and/or
    testing.
    
    Directly putting image onto RAM would speed up upgrade process. This and
    convenience was the initial thoughts that led to doing this, speed
    improvement over MMC was only 1 second though - 6 sec on RAM as opposed
    to 7 sec on MMC in beagle bone, perhaps enabling cache and/or optimizing
    DFU framework to avoid multiple copy for ram (if worth) may help, and
    on other platforms and other boot media like NAND maybe improvement
    would be higher.
    
    And for a platform that doesn't yet have proper DFU suppport for
    non-volatile media's, DFU to RAM can be used.
    
    Another minor advantage would be to increase life of mmc/nand as it
    would be less used during development/testing.
    
    usage: <image name> ram <start address> <size>
    eg. kernel ram 0x81000000 0x1000000
    
    Downloading images to RAM using DFU is not something new, this is
    acheived in openmoko also.
    
    DFU on RAM can be used for extracting RAM contents to host using dfu
    upload. Perhaps this can be extended to io for squeezing out register
    dump through usb, if it is worth.
    Signed-off-by: default avatarAfzal Mohammed <afzal.mohd.ma@gmail.com>
    Cc: Heiko Schocher <hs@denx.de>
    Cc: Marek Vasut <marex@denx.de>
    Cc: Lukasz Majewski <l.majewski@samsung.com>
    Cc: Pantelis Antoniou <panto@antoniou-consulting.com>
    Cc: Gerhard Sittig <gsi@denx.de>
    Acked-by: default avatarMarek Vasut <marex@denx.de>
    Acked-by: default avatarLukasz Majewski <l.majewski@samsung.com>
    Acked-by: default avatarHeiko Schocher <hs@denx.de>
    a9479f04
dfu_ram.c 1.64 KB