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    ARM: imx: add suspend in ocram support for i.mx6q · df595746
    Anson Huang 提交于
    When system enter suspend, we can set the DDR IO to
    high-Z state to save DDR IOs' power consumption, this
    operation can save many power(from ~26mA@1.5V to ~15mA@1.5V,
    measured on i.MX6Q SabreSD board, R25) of DDR IOs. To
    achieve that, we need to copy the suspend code to ocram
    and run the low level hardware related code(set DDR IOs
    to high-Z state) in ocram.
    
    If there is no ocram space available, then system will
    still do suspend in external DDR, hence no DDR IOs will
    be set to high-Z.
    
    The OCRAM usage layout is as below,
    
    ocram suspend region(4K currently):
    ======================== high address ======================
                                  .
                                  .
                                  .
                                  ^
                                  ^
                                  ^
                          imx6_suspend code
                 PM_INFO structure(imx6_cpu_pm_info)
    ======================== low address =======================
    Reviewed-by: NSascha Hauer <s.hauer@pengutronix.de>
    Signed-off-by: NAnson Huang <b20788@freescale.com>
    Signed-off-by: NShawn Guo <shawn.guo@linaro.org>
    df595746
hardware.h 4.7 KB