S3C2440电源管理有关问题及其解决方法
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关于2440的电源管理调试出现过的问题以及解决方法：
1、系统睡眠与唤醒，拿到普通的代码，出现的问题经常是进入睡眠后，GPIO唤醒总是导致系统重新启动，其实这是因为没有设置CPU的运行模式，而这运行模式是通过设置GPG13，GPG14，GPG15来进行的。所以就要想唤醒后恢复到睡眠之前的状态，则要在进入睡眠前设置这三个GPIO的模式，可以在arch/arm/plat-s3c24xx/pm.c文件中的s3c2410_pm_enter（）中在进入谁面前，也就是执行__raw_writel(0x00, S3C2410_CLKCON)前加入如下三条语句：
__raw_writel(__raw_readl(S3C2410_EINTPEND), S3C2410_EINTPEND);
__raw_writel(__raw_readl(S3C2410_INTPND), S3C2410_INTPND);
__raw_writel(__raw_readl(S3C2410_SRCPND), S3C2410_SRCPND);
即可使系统恢复正常。
附：
我修改的s3c2410_pm_enter函数如下：
static int s3c2410_pm_enter(suspend_state_t state)
{
unsigned long regs_save[16];
int tmp;
/* ensure the debug is initialised (if enabled) */
s3c2410_pm_debug_init();
DBG("s3c2410_pm_enter(%d)n", state);
/* our board doesn't support hard disk.*/
if (state != PM_SUSPEND_MEM) {
printk(KERN_ERR PFX "error: only PM_SUSPEND_MEM supportedn");
return -EINVAL;
}
if (pm_cpu_prep == NULL || pm_cpu_sleep == NULL) {
printk(KERN_ERR PFX "error: no cpu sleep functions setn");
return -EINVAL;
}
/* configure pin GPF4 for wake-up */
//enable_irq_wake(IRQ_EINT4);
//s3c2410_gpio_cfgpin(S3C2410_GPF4,S3C2410_GPF4_EINT4);
//set_irq_type(IRQ_EINT4, IRQT_BOTHEDGE);
tmp = __raw_readl(S3C2410_EINTMASK);
tmp &= ~(1UL<<4);
__raw_writel(tmp,S3C2410_EINTMASK);
s3c2410_gpio_cfgpin(S3C2410_GPG13,S3C2410_GPG13_INP);//tfirst
s3c2410_gpio_cfgpin(S3C2410_GPG14,S3C2410_GPG14_INP);//tfirst
s3c2410_gpio_cfgpin(S3C2410_GPG15,S3C2410_GPG15_INP);//tfirst
/* check if we have anything to wake-up with... bad things seem
* to happen if you suspend with no wakeup (system will often
* require a full power-cycle)
*/
if (!any_allowed(s3c_irqwake_intmask, s3c_irqwake_intallow) &&
!any_allowed(s3c_irqwake_eintmask, s3c_irqwake_eintallow)) {
printk(KERN_ERR PFX "No sources enabled for wake-up!n");
printk(KERN_ERR PFX "Aborting sleepn");
return -EINVAL;
}
/* prepare check area if configured */
s3c2410_pm_check_prepare();
/* set USB pad as suspend mode ,tfirst add ,2009-05-27 */
__raw_writel(__raw_readl(S3C2410_MISCCR) | (3<<12),S3C2410_MISCCR);
/* store the physical address of the register recovery block */
s3c2410_sleep_save_phys = virt_to_phys(regs_save);
DBG("s3c2410_sleep_save_phys=0x%08lxn", s3c2410_sleep_save_phys);
/* save resume address */
__raw_writel(virt_to_phys(s3c2410_cpu_resume), S3C2410_GSTATUS3);
/*clear the General Status Registers reg 2*/
__raw_writel(0xff,S3C2410_GSTATUS2);
/* save all necessary core registers not covered by the drivers */
s3c2410_pm_do_save(misc_save, ARRAY_SIZE(misc_save));
s3c2410_pm_do_save(gpio_save, ARRAY_SIZE(gpio_save));
s3c2410_pm_do_save(core_save, ARRAY_SIZE(core_save));
s3c2410_pm_do_save(uart_save, ARRAY_SIZE(uart_save));
/* set the irq configuration for wake */
s3c2410_pm_configure_extint();
DBG("sleep: irq wakeup masks: %08lx,%08lxn",
s3c_irqwake_intmask, s3c_irqwake_eintmask);
__raw_writel(s3c_irqwake_intmask, S3C2410_INTMSK);
__raw_writel(s3c_irqwake_eintmask, S3C2410_EINTMASK);
/* ack any outstanding external interrupts before we go to sleep */
__raw_writel(__raw_readl(S3C2410_EINTPEND), S3C2410_EINTPEND);
__raw_writel(__raw_readl(S3C2410_INTPND), S3C2410_INTPND);
__raw_writel(__raw_readl(S3C2410_SRCPND), S3C2410_SRCPND);
/* call cpu specific preparation */
pm_cpu_prep();
/* flush cache back to ram */
flush_cache_all();
s3c2410_pm_check_store();
/* send the cpu to sleep... */
__raw_writel(0x00, S3C2410_CLKCON); /* turn off clocks over sleep */
/* s3c2410_cpu_save will also act as our return point from when
* we resume as it saves its own register state, so use the return
* code to differentiate return from save and return from sleep */
if (s3c2410_cpu_save(regs_save) == 0) {
flush_cache_all();
pm_cpu_sleep();
}
/* restore the cpu state */
cpu_init();
/*unset the return-from-sleep flag, to ensure reset */
tmp = __raw_readl(S3C2410_GSTATUS2);
tmp |= S3C2410_GSTATUS2_OFFRESET;
__raw_writel(tmp, S3C2410_GSTATUS2);
/* restore the system state */
s3c2410_pm_do_restore_core(core_save, ARRAY_SIZE(core_save));
s3c2410_pm_do_restore(misc_save, ARRAY_SIZE(misc_save));//
s3c2410_pm_do_restore(gpio_save, ARRAY_SIZE(gpio_save));
s3c2410_pm_do_restore(uart_save, ARRAY_SIZE(uart_save));
s3c2410_pm_debug_init();
/* check what irq (if any) restored the system */
DBG("post sleep: IRQs 0x%08x, 0x%08xn",
__raw_readl(S3C2410_SRCPND),
__raw_readl(S3C2410_EINTPEND));
s3c2410_pm_show_resume_irqs(IRQ_EINT0, __raw_readl(S3C2410_SRCPND),
s3c_irqwake_intmask);
s3c2410_pm_show_resume_irqs(IRQ_EINT4-4, __raw_readl(S3C2410_EINTPEND),
s3c_irqwake_eintmask);
DBG("post sleep, preparing to returnn");
s3c2410_pm_check_restore();
/* ok, let's return from sleep */
dump_irq_reg();
DBG("S3C2410 PM Resume (post-restore)n");
return 0;
}
2、在调试的过程中，出现过系统无法进入睡眠的情况。情况大概是串口终端已经进入睡眠了，系统停止了，但是用精密电源去测，发现电流还是没有下降，通过跟踪，才知道系统逐个调用各个驱动的suspend，按照s3c2410-ts.c原来提供的驱动结构:
static struct platform_driver s3c2410ts_driver = {
.name = "s3c2410-ts",
.bus = &platform_bus_type,
.probe = s3c2410ts_probe,
.remove = s3c2410ts_remove,
};
，系统无法使得触摸品进入睡眠，至于什么原因，不是很理解，将驱动的系统注册接口改为如下：
static struct platform_driver s3c2410ts_driver= {
.probe= s3c2410ts_probe,
.remove= s3c2410ts_remove,
.suspend= s3c2410ts_suspend,
.resume= s3c2410ts_resume,
.driver= {
.name= "s3c2410-ts",
.owner= THIS_MODULE,
},
};
系统就可以进入睡眠了。
3.在调试的过程中，还出现过跟LCD唤醒相关的问题。主要就是两个问题
一个问题是，在唤醒LCD之后，LCD会花屏。原以为拿到的这个代码已经做好了睡眠/唤醒，看了代码才发现，这个代码在睡眠之前，没有保存LCD的设置，在唤醒之后是重新初始化LCD的控制器，所以会出现花屏的现象，所以自己重新实现了s3c2410fb_suspend和s3c2410fb_resume两个函数，代码如下：
static int s3c2410fb_suspend(struct platform_device *dev, pm_message_t state)
{
struct fb_info *fbinfo = platform_get_drvdata(dev);
struct s3c2410fb_info *info = fbinfo->par;
unsigned long flags;
s3c2410fb_stop_lcd(info);
local_irq_save(flags);
lcdcon1 = readl(info->io + S3C2410_LCDCON1);
lcdcon2 = readl(info->io + S3C2410_LCDCON2);
lcdcon3 = readl(info->io + S3C2410_LCDCON3);
lcdcon4 = readl(info->io + S3C2410_LCDCON4);
lcdcon5 = readl(info->io + S3C2410_LCDCON5);
lcdsaddr1 = readl(info->io + S3C2410_LCDSADDR1);
lcdsaddr2 = readl(info->io + S3C2410_LCDSADDR2);
lcdsaddr3 = readl(info->io + S3C2410_LCDSADDR3);
redlut = readl(info->io + S3C2410_REDLUT);
greenlut = readl(info->io + S3C2410_GREENLUT);
bluelut = readl(info->io + S3C2410_BLUELUT);
dithmode = readl(info->io + S3C2410_DITHMODE);
tpal = readl(info->io + S3C2410_TPAL);
lcdintpnd = readl(info->io + S3C2410_LCDINTPND);
lcdsrcpnd = readl(info->io + S3C2410_LCDSRCPND);
lcdintmsk = readl(info->io + S3C2410_LCDINTMSK);
lpcsel = readl(info->io + S3C2410_LPCSEL);
lcdcon1 &= ~S3C2410_LCDCON1_ENVID;
local_irq_restore(flags);
/* sleep before disabling the clock, we need to ensure
* the LCD DMA engine is not going to get back on the bus
* before the clock goes off again (bjd) */
msleep(1);
clk_disable(info->clk);
/*
* shutdown the LCD power and backlight power
*/
s3c2410_gpio_setpin(S3C2410_GPG12, 0);
s3c2410_gpio_setpin(S3C2410_GPG4, 1);
return 0;
}
static int s3c2410fb_resume(struct platform_device *dev)
{
struct fb_info *fbinfo = platform_get_drvdata(dev);
struct s3c2410fb_info *info = fbinfo->par;
struct s3c2410fb_mach_info *mach_info = info->dev->platform_data;
unsigned long flags;
int i;
printk("=======framebuffer resume.=====n");
s3c2410_gpio_setpin(S3C2410_GPG4, 0);
msleep(10);
//s3c2410_gpio_setpin(S3C2410_GPG12, 1);
//msleep(10);
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