• Joseph Lo's avatar
    ARM: tegra: add common LP1 suspend support · 95872f42
    Joseph Lo authored
    The LP1 suspending mode on Tegra means CPU rail off, devices and PLLs are
    clock gated and SDRAM in self-refresh mode. That means the low level LP1
    suspending and resuming code couldn't be run on DRAM and the CPU must
    switch to the always on clock domain (a.k.a. CLK_M 12MHz oscillator). And
    the system clock (SCLK) would be switched to CLK_S, a 32KHz oscillator.
    The LP1 low level handling code need to be moved to IRAM area first. And
    marking the LP1 mask for indicating the Tegra device is in LP1. The CPU
    power timer needs to be re-calculated based on 32KHz that was originally
    based on PCLK.
    
    When resuming from LP1, the LP1 reset handler will resume PLLs and then
    put DRAM to normal mode. Then jumping to the "tegra_resume" that will
    restore full context before back to kernel. The "tegra_resume" handler
    was expected to be found in PMC_SCRATCH41 register.
    
    This is common LP1 procedures for Tegra, so we do these jobs mainly in
    this patch:
    * moving LP1 low level handling code to IRAM
    * marking LP1 mask
    * copying the physical address of "tegra_resume" to PMC_SCRATCH41
    * re-calculate the CPU power timer based on 32KHz
    Signed-off-by: default avatarJoseph Lo <josephl@nvidia.com>
    [swarren, replaced IRAM_CODE macro with IO_ADDRESS(TEGRA_IRAM_CODE_AREA)]
    Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
    95872f42
pmc.h 1.41 KB