研发干货丨关于RK3399 开发板休眠、关机功能简析
文章目录
Power按键
~短按休眠和长按关机
关机命令
~poweroff命令关机
OK3399-C平台采用RK3399 主CPU芯片设计，支持底板Power按键休眠唤醒以及关机功能，Linux命令行也可以通过命令进行关机，下面对这两种方式进行简单的解析。
Power按键
Power按键的休眠唤醒功能一般是与PMIC芯片和CPU相关的，硬件上该按键会连接到PMIC的PWRON引脚和CPU对应的引脚上。
先来看power按键在PMIC侧的响应机制，POWER键按下以后，经过TdbPWRONF时间以后，INT引脚变为低电平，触发中断。内核驱动响应中断，执行休眠程序。
如果PWRON继续保持低电平超过TdPWRONLP，PMIC就会响应，RK3399板卡将进行关机。
短按休眠和长按关机
Log信息：
[ 10.250531] PM: Syncing filesystems ... done.[ 10.255148] test message. //加入的测试信息[ 10.256842] Freezing user space processes ... (elapsed 0.003 seconds) done.[ 10.260770] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done. [ 10.263308] Suspending console(s) (use no_console_suspend to debug)INFO: sleep mode config[0xde]:INFO: AP_PWROFFINFO: SLP_ARMPD INFO: SLP_PLLPDINFO: DDR_RETINFO: SLP_CENTER_PDINFO: wakeup source config[0x804]:INFO: GPIO interrupt can wakeup systemINFO: PWM interrupt can wakeup systemINFO: PWM CONFIG[0x4]:INFO: PWM: PWM2D_REGULATOR_ENINFO: APIOS info[0x0]:INFO: not configINFO: GPIO POWER INFO:INFO: GPIO1_C1INFO: GPIO1_B6INFO: PMU_MODE_CONG: 0x1477bf51
涉及驱动文件
kernel/kernel/power/suspend.c
/** * enter_state - Do common work needed to enter system sleep state. * @state: System sleep state to enter. * * Make sure that no one else is trying to put the system into a sleep state. * Fail if that's not the case. Otherwise, prepare for system suspend, make the * system enter the given sleep state and clean up after wakeup. */static int enter_state(suspend_state_t state){ int error; trace_suspend_resume(TPS("suspend_enter"), state, true); if (state == PM_SUSPEND_FREEZE) {#ifdef CONFIG_PM_DEBUG if (pm_test_level != TEST_NONE && pm_test_level <= TEST_CPUS) { pr_warning("PM: Unsupported test mode for suspend to idle," "please choose none/freezer/devices/platform.\n"); return -EAGAIN; }#endif } else if (!valid_state(state)) { return -EINVAL; } if (!mutex_trylock(&pm_mutex)) return -EBUSY; if (state == PM_SUSPEND_FREEZE) freeze_begin();#ifndef CONFIG_SUSPEND_SKIP_SYNC trace_suspend_resume(TPS("sync_filesystems"), 0, true); printk(KERN_INFO "PM: Syncing filesystems ... "); sys_sync(); printk("done.\n"); trace_suspend_resume(TPS("sync_filesystems"), 0, false);#endif pr_debug("PM: Preparing system for sleep (%s)\n", pm_states[state]); pm_suspend_clear_flags(); error = suspend_prepare(state); if (error) goto Unlock; if (suspend_test(TEST_FREEZER)) goto Finish; trace_suspend_resume(TPS("suspend_enter"), state, false); pr_debug("PM: Suspending system (%s)\n", pm_states[state]); pm_restrict_gfp_mask(); error = suspend_devices_and_enter(state); pm_restore_gfp_mask(); Finish: pr_debug("PM: Finishing wakeup.\n"); suspend_finish(); Unlock: mutex_unlock(&pm_mutex); return error;}
通过代码可知，Power按键触发的休眠和关机会执行sys_sync函数，进行系统数据的保存，这与突然掉电导致的异常关机是有很大区别的。
关机命令
RK3399 平台Linux下的关机命令有shutdown、halt、poweroff命令等.
Poweroff命令关机
Log信息：
[root@rk3399:/]# poweroff[root@rk3399:/]# stop finishedStopping input-event-daemon: donestop auto-reboot finishedStopping dnsmasq: OKStopping vsftpd: stopped vsftpd (pid 1072)OK[ 20.099392] [BT_RFKILL]: bt shut off power[ 20.132245] configfs-gadget gadget: unbind function 'Function FS Gadget'/ffffffc07b025a38Stopping sshd: OKStopping lighttpd: OKGracefully shutting down php-fpm . doneStopping dhcpcd...stopped /sbin/dhcpcd (pid 924)killall: rkisp_3A_server: no process killedStopping network: OKstop finishedStopping system message bus: doneSaving random seed... done.Stopping logging: OKumount: can't remount adb read-onlyumount: devtmpfs busy - remounted read-only[ 21.589884] EXT4-fs (mmcblk2p8): re-mounted. Opts: (null)The system is going down NOW! Sent SIGTERM to all processesSent SIGKILL to all processesRequesting system poweroff[ 23.597578] cpu cpu4: min=816000, max=816000[ 23.598572] cpu cpu0: min=816000, max=816000[ 23.669985] I : [File] : drivers/gpu/arm/midgard_for_linux/platform/rk/mali_kbase_config_rk.c; [Line] : 274; [Func] : kbase_platform_rk_shutdown(); to make vdd_gpu enabled for turning off pd_gpu in pm_framework.[ 23.671701] rk-vcodec ff660000.rkvdec: shutdown[ 23.672132] rk-vcodec ff650000.vpu_service: shutdown[ 23.673046] rk808 0-001b: System power off[ 23.673419] rk808 0-001b: test message //加入的测试信息
[root@rk3399:/]# poweroff --helpBusyBox v1.27.2 (2020-03-19 09:39:13 UTC) multi-call binary.Usage: poweroff [-d DELAY] [-n] [-f]Halt and shut off power -d SEC Delay interval -n Do not sync -f Force (don't go through init)
Poweroff命令做的事可以从打印信息上看出来，其实可以分为两部分，一是配置系统，停止当前的服务，进行数据保存。二是调用电源管理驱动对应的接口，完成电源配置，RK3399 主板进行关机。
涉及驱动文件
kernel/drivers/mfd/rk808.c
static void rk808_syscore_shutdown(void){ int ret; struct rk808 *rk808 = i2c_get_clientdata(rk808_i2c_client); if (!rk808) { dev_warn(&rk808_i2c_client->dev, "have no rk808, so do nothing here\n"); return; } /* close rtc int when power off */ regmap_update_bits(rk808->regmap, RK808_INT_STS_MSK_REG1, (0x3 << 5), (0x3 << 5)); regmap_update_bits(rk808->regmap, RK808_RTC_INT_REG, (0x3 << 2), (0x0 << 2)); /* * For PMIC that power off supplies by write register via i2c bus, * it's better to do power off at syscore shutdown here. * * Because when run to kernel's "pm_power_off" call, i2c may has * been stopped or PMIC may not be able to get i2c transfer while * there are too many devices are competiting. */ if (system_state == SYSTEM_POWER_OFF) { /* power off supplies ! */ if (pm_shutdown) { dev_info(&rk808_i2c_client->dev, "System power off\n"); ret = pm_shutdown(rk808->regmap); if (ret) dev_err(&rk808_i2c_client->dev, "System power off error!\n"); mdelay(10); dev_info(&rk808_i2c_client->dev, "Cpu should never reach here, stop!\n"); while (1) ; } }}#define DEV_OFF_RST BIT(3)static int rk808_shutdown(struct regmap *regmap){ int ret; ret = regmap_update_bits(regmap, RK808_DEVCTRL_REG, DEV_OFF_RST, DEV_OFF_RST); return ret;}
最终调用的的rk808shutdown接口函数，对RK808DEVCTRLREG寄存器写入DEVOFF_RST，触发RK3399主板关机。
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