reboot ..

最後 reset 是...arm/arm/mach-kk40/reset.c

static void kk40_arch_reset(char mode, const char *cmd)
{
        u32 boot_flag = 0;
        u32 boot_mode = BOOT_MODE_REBOOT;

        if (cmd) {
                if (!strcmp(cmd, "loader") || !strcmp(cmd, "bootloader"))
                        boot_flag = SYS_LOADER_REBOOT_FLAG + BOOT_LOADER;
                else if(!strcmp(cmd, "recovery"))
                        boot_flag = SYS_LOADER_REBOOT_FLAG + BOOT_RECOVER;
                else if (!strcmp(cmd, "charge"))
                        boot_mode = BOOT_MODE_CHARGE;
        } else {
                if (is_panic)
                        boot_mode = BOOT_MODE_PANIC;
        }
#ifndef RK30_PMU_BASE
        writel_relaxed(boot_flag, RK30_GRF_BASE + GRF_OS_REG4); // for loader
        writel_relaxed(boot_mode, RK30_GRF_BASE + GRF_OS_REG5); // for linux
#else
        writel_relaxed(boot_flag, RK30_PMU_BASE + PMU_SYS_REG0);        // for loader
        writel_relaxed(boot_mode, RK30_PMU_BASE + PMU_SYS_REG1);        // for linux
#endif
 ....

所以會reboot flag 和 mode 會被寫入 cpu register...