Android4.0.3 USB OTG底层插入上报过程分析

下面的两个宏是PM8058的MMP11（R15），MMP12（P15）管脚。
#define EXT_CHG_VALID_MPP 10
#define EXT_CHG_VALID_MPP_2 11

static struct pm8xxx_mpp_init_info isl_mpp[] = {
PM8058_MPP_INIT(EXT_CHG_VALID_MPP, D_INPUT,
PM8058_MPP_DIG_LEVEL_S3, DIN_TO_INT),
PM8058_MPP_INIT(EXT_CHG_VALID_MPP_2, D_BI_DIR,
PM8058_MPP_DIG_LEVEL_S3, BI_PULLUP_10KOHM),
};

//配置管脚功能函数
#if defined(CONFIG_SMB137B_CHARGER) || defined(CONFIG_SMB137B_CHARGER_MODULE)
static int smb137b_detection_setup(void)
{
int ret = 0, i;

for (i = 0; i < ARRAY_SIZE(isl_mpp); i++) {
ret = pm8xxx_mpp_config(isl_mpp[i].mpp,&isl_mpp[i].config);
}

return ret;
}

static struct smb137b_platform_data smb137b_data __initdata = {
.chg_detection_config = smb137b_detection_setup,
.valid_n_gpio = PM8058_MPP_PM_TO_SYS(10),
.batt_mah_rating = 950,
};

static struct i2c_board_info smb137b_charger_i2c_info[] __initdata = {
{
I2C_BOARD_INFO("smb137b", 0x08),
.irq = PM8058_IRQ_BASE + PM8058_CBLPWR_IRQ,//计算后的irq值＝464
.platform_data = &smb137b_data,
},
};
#endif


static int __devinit smb137b_probe(struct i2c_client *client,const struct i2c_device_id *id)
｛
/*配置usb检测管脚*/
if (pdata->chg_detection_config)
ret = pdata->chg_detection_config();

/*用该检测gpio引脚前，申请该GPIO*/
ret = gpio_request(pdata->valid_n_gpio, "smb137b_charger_valid");

/*申请中断，该中断号码为464*/
ret = request_threaded_irq(client->irq, NULL,smb137b_valid_handler,
IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
"smb137b_charger_valid", client);

/*先读取一次检测管脚值*/
ret = gpio_get_value_cansleep(smb137b_chg->valid_n_gpio);
if (!ret) {

/*上报usb的插入状态*/
msm_charger_notify_event(smb137b_chg->adapter_hw_chg[0],CHG_INSERTED_EVENT);
smb137b_chg->usb_status = SMB137B_PRESENT;
}
｝
/*以后的处理都是在中断中进行处理*/
static irqreturn_t smb137b_valid_handler(int irq, void *dev_id)
{
struct smb137b_data *smb137b_chg;

smb137b_chg = i2c_get_clientdata(client);
smb137b_chg->current_hw_chg = smb137b_chg->adapter_hw_chg[0];

/*读出检测管脚的电平值*/
val = gpio_get_value_cansleep(smb137b_chg->valid_n_gpio);

if (val) {
if (smb137b_chg->usb_status != SMB137B_ABSENT) {
smb137b_chg->usb_status = SMB137B_ABSENT;
/*如果为高电平，通知usb移出*/
msm_charger_notify_event(smb137b_chg->current_hw_chg,CHG_REMOVED_EVENT);
}
} else if (smb137b_chg->usb_status == SMB137B_ABSENT) {
smb137b_chg->usb_status = SMB137B_PRESENT;
/*如果为高电平，通知usb插入*/
msm_charger_notify_event(smb137b_chg->current_hw_chg,CHG_INSERTED_EVENT);
}
｝
下面进入发通知流程继续跟踪
int msm_charger_notify_event(struct msm_hardware_charger *hw_chg,
enum msm_hardware_charger_event event)
{
/*把该消息加入循环队列中*/
msm_chg_enqueue_event(hw_chg, event);

/*调度work*/
queue_work(msm_chg.event_wq_thread, &msm_chg.queue_work);
return 0;
}
下面的两行是在static int __init msm_charger_init(void)函数中进行初始化的：

INIT_WORK(&msm_chg.queue_work, process_events);
msm_chg.event_wq_thread = create_workqueue("msm_charger_eventd");
该work的处理函数如下：
static void process_events(struct work_struct *work)
{
struct msm_charger_event *event;
int rc;
/*循环处理等待队列中的消息*/
do {
rc = msm_chg_dequeue_event(&event);
if (!rc)
/*对单个的event进行处理*/
handle_event(event->hw_chg, event->event);
} while (!rc);
}
下面进入具体的handle_event函数分析：
static void handle_event(struct msm_hardware_charger *hw_chg, int event)
{
struct msm_hardware_charger_priv *priv = NULL;

if (hw_chg)
priv = hw_chg->charger_private;

switch (event) {
case CHG_INSERTED_EVENT:
if (hw_chg->type == CHG_TYPE_USB) {
.................
priv->hw_chg_state = CHG_PRESENT_STATE;

/*上报usb插入事件*/
notify_usb_of_the_plugin_event(priv, 1);
.........................
break;
case CHG_REMOVED_EVENT:
if (hw_chg->type == CHG_TYPE_USB) {
...............
usb_chg_current = 0;

/*上报usb移出事件*/
notify_usb_of_the_plugin_event(priv, 0);
........................
}
break;
}

/*进入notify_usb_of_the_plugin_event函数继续跟踪*/
static void notify_usb_of_the_plugin_event(struct msm_hardware_charger_priv
*hw_chg, int plugin)
{
plugin = !!plugin;
if (plugin == 1 && usb_notified_of_insertion == 0) {
usb_notified_of_insertion = 1;
if (notify_vbus_state_func_ptr) {
/*调用回调函数*/
(*notify_vbus_state_func_ptr) (plugin);
}
if (plugin == 0 && usb_notified_of_insertion == 1) {
if (notify_vbus_state_func_ptr) {
(*notify_vbus_state_func_ptr) (plugin);
}
usb_notified_of_insertion = 0;
}
}
/*下面进入回调函数的跟踪*/
/*在板级初始化时定义了一个全局函数指针*/
notify_vbus_state notify_vbus_state_func_ptr;

/*该函数指针在该回调函数中赋值*/
static int msm_hsusb_pmic_vbus_notif_init(void (*callback)(int online),
int init)
{
int ret = -ENOTSUPP;
if (machine_is_msm8x60_s9000() || pmic_id_notif_supported)) {
if (init)
ret = msm_charger_register_vbus_sn(callback);
else {
msm_charger_unregister_vbus_sn(callback);
ret = 0;
}
}
}
int msm_charger_register_vbus_sn(void (*callback)(int))
{
notify_vbus_state_func_ptr = callback;
return 0;
}

/*该回调函数注册的时机如下*/
#if defined(CONFIG_USB_GADGET_MSM_72K) || defined(CONFIG_USB_EHCI_MSM_72K)
static struct msm_otg_platform_data msm_otg_pdata = {
................
#ifdef CONFIG_BATTERY_MSM8X60
.pmic_vbus_notif_init = msm_hsusb_pmic_vbus_notif_init,
#endif
.........................

};
#endif
/*把该平台数据赋值给平台设备*/
msm_device_otg.dev.platform_data = &msm_otg_pdata;

/*注册该平台设备*/
static struct platform_device *surf_devices[] __initdata = {
#if defined(CONFIG_USB_GADGET_MSM_72K) || defined(CONFIG_USB_EHCI_HCD)
&msm_device_otg,
#endif
｝
static void __init msm8x60_init(struct msm_board_data *board_data)
｛
platform_add_devices(surf_devices,ARRAY_SIZE(surf_devices));
｝
static int __init msm_otg_probe(struct platform_device *pdev)
{
..............
/*初始化work工作队列*/
INIT_WORK(&dev->sm_work, msm_otg_sm_work);
dev->wq = alloc_workqueue("k_otg", WQ_NON_REENTRANT, 0);
..................
/*调用回调函数，为全局函数指针赋值*/
if (dev->pdata->pmic_vbus_notif_init) {
ret = dev->pdata->pmic_vbus_notif_init
(&msm_otg_set_vbus_state, 1);
if (!ret) {
dev->pmic_vbus_notif_supp = 1;
}
}
...............
.......................
}
/*然后用该函数上报plug的值*/
void msm_otg_set_vbus_state(int online)
{
struct msm_otg *dev = the_msm_otg;

/*如果上报插入事件，就设置B_SESS_VLD标志位*/
if (online)
set_bit(B_SESS_VLD, &dev->inputs);
/*如果上报移除事件，就清除B_SESS_VLD标志位*/
else
clear_bit(B_SESS_VLD, &dev->inputs);

/*获得wakelock锁*/
wake_lock(&dev->wlock);

/*调度工作队列中的work*/
queue_work(dev->wq, &dev->sm_work);
}
/*下面进入work继续跟踪*/
static void msm_otg_sm_work(struct work_struct *w)
｛
enum usb_otg_state state;
state = dev->otg.state;
switch (state) {
case OTG_STATE_UNDEFINED:
if (!dev->otg.host || !is_host())
{
set_bit(ID, &dev->inputs);
}

if (dev->otg.gadget && is_b_sess_vld())
{
set_bit(B_SESS_VLD, &dev->inputs);
}

if ((test_bit(ID, &dev->inputs)) && !test_bit(ID_A, &dev->inputs)) {
/*改变otg的状态机状态为OTG_STATE_B_IDLE*/
dev->otg.state = OTG_STATE_B_IDLE;
}
work = 1;
break;
case OTG_STATE_B_IDLE:
if (test_bit(B_SESS_VLD, &dev->inputs) && !test_bit(ID_B, &dev->inputs)) {
/*改变otg的状态机状态为OTG_STATE_B_PERIPHERAL*/
dev->otg.state = OTG_STATE_B_PERIPHERAL;

msm_otg_set_power(&dev->otg, 0);

/*启动外围设备*/
msm_otg_start_peripheral(&dev->otg, 1);
}
break;
/*如果work为1，则继续调度work*/
if (work)
queue_work(dev->wq, &dev->sm_work);
｝
/*上面的work牵涉到两个函数，通过寄存器的值判断，设置相应的位域*/
static int is_host(void)
{
struct msm_otg *dev = the_msm_otg;

if (dev->pdata->otg_mode == OTG_ID)
{
/*读出该寄存器的第8位，如果读出的为1，则返回0，即该设备为B device*/
return (OTGSC_ID & readl(USB_OTGSC)) ? 0 : 1;
}
}

static int is_b_sess_vld(void)
{
struct msm_otg *dev = the_msm_otg;

if (dev->pdata->otg_mode == OTG_ID)
{
/*读出该寄存器的第11位，如果为1，则返回1，该寄存器在spec中说明如下：Indicates that the Vbus is above the B session valid threshold.*/
return (OTGSC_BSV & readl(USB_OTGSC)) ? 1 : 0;
}
}
/*下面进入msm_otg_start_peripheral函数进行分析*/
static void msm_otg_start_peripheral(struct otg_transceiver *xceiv, int on)
{
struct msm_otg *dev = container_of(xceiv, struct msm_otg, otg);
if (on) {
usb_gadget_vbus_connect(xceiv->gadget);
}
}
/*设置gadget的vbus*/
static inline int usb_gadget_vbus_connect(struct usb_gadget *gadget)
{
if (!gadget->ops->vbus_session)
return -EOPNOTSUPP;
return gadget->ops->vbus_session(gadget, 1);
}
/*调用底层gadget的回调函数*/
gadget->ops->vbus_session(gadget, 1);

/*下面是该回调函数的结构体*/
static const struct usb_gadget_ops msm72k_ops = {
.get_frame = msm72k_get_frame,
/*该回调函数*/
.vbus_session = msm72k_udc_vbus_session,
.vbus_draw = msm72k_udc_vbus_draw,
.pullup = msm72k_pullup,
.wakeup = msm72k_wakeup,
.set_selfpowered = msm72k_set_selfpowered,
};
/*回调函数的注册过程如下*/
static int msm72k_probe(struct platform_device *pdev)
{
ui = kzalloc(sizeof(struct usb_info), GFP_KERNEL);
ui->gadget.ops = &msm72k_ops;
}
/*看下vbus的回调函数*/
static int msm72k_udc_vbus_session(struct usb_gadget *_gadget, int is_active)
{
/*设置vbus的状态*/
msm_hsusb_set_vbus_state(is_active);
return 0;
}
/*继续跟踪设置vbus的状态*/
void msm_hsusb_set_vbus_state(int online)
{
struct usb_info *ui = the_usb_info;

/*根据传入的状态设置usb的状态位*/
if (online) {
ui->usb_state = USB_STATE_POWERED;
ui->flags |= USB_FLAG_VBUS_ONLINE;
} else {
ui->gadget.speed = USB_SPEED_UNKNOWN;
ui->usb_state = USB_STATE_NOTATTACHED;
ui->flags |= USB_FLAG_VBUS_OFFLINE;
}

/*调度usb的工作队列*/
if (in_interrupt()) {
schedule_work(&ui->work);
} else {
usb_do_work(&ui->work);
return;
}
}
/*在usb_do_work中会进入一个大的状态机循环*/
static void usb_do_work(struct work_struct *w)
{
struct usb_info *ui = container_of(w, struct usb_info, work);
struct msm_otg *otg = to_msm_otg(ui->xceiv);
unsigned long iflags;
unsigned flags, _vbus;

for (;;) {
spin_lock_irqsave(&ui->lock, iflags);
flags = ui->flags;
ui->flags = 0;
_vbus = is_usb_online(ui);
spin_unlock_irqrestore(&ui->lock, iflags);

/* give up if we have nothing to do */
if (flags == 0)
break;

switch (ui->state) {
case USB_STATE_IDLE:
if (flags & USB_FLAG_START) {
int ret;
/*重启设备控制器*/
usb_reset(ui);

/*申请中断处理函数*/
ret = request_irq(otg->irq, usb_interrupt,IRQF_SHARED,ui->pdev->name, ui);
ui->irq = otg->irq;

/*改变设备状态*/
ui->state = USB_STATE_ONLINE;
usb_do_work_check_vbus(ui);

/*使能D＋数据线上的上拉电阻*/
msm72k_pullup_internal(&ui->gadget, 1);
break;
case USB_STATE_ONLINE:
if (flags & USB_FLAG_SUSPEND) {
int maxpower = usb_get_max_power(ui);
otg_set_power(ui->xceiv, 0);
break;
}
if (flags & USB_FLAG_CONFIGURED) {
int maxpower = usb_get_max_power(ui);
switch_set_state(&ui->sdev,atomic_read(&ui->configured));
ui->chg_current = maxpower;
otg_set_power(ui->xceiv, maxpower);
break;
}
if (flags & USB_FLAG_RESET) {
msm72k_pullup_internal(&ui->gadget, 0);
usb_reset(ui);
msm72k_pullup_internal(&ui->gadget, 1);
break;
}
break;
case USB_STATE_OFFLINE:
if ((flags & USB_FLAG_VBUS_ONLINE) && _vbus) {
/*重启设备控制器*/
usb_reset(ui);

/*改变设备状态*/
ui->state = USB_STATE_ONLINE;
usb_do_work_check_vbus(ui);

/*申请中断处理函数*/
ret = request_irq(otg->irq, usb_interrupt,IRQF_SHARED,ui->pdev->name, ui);
ui->irq = otg->irq;

/*使能D＋数据线上的上拉电阻*/
msm72k_pullup_internal(&ui->gadget, 1);
}
break;
}
}
}

/*中断函数的实时处理*/
static irqreturn_t usb_interrupt(int irq, void *data)
{
struct usb_info *ui = data;
unsigned n;
unsigned long flags;

n = readl(USB_USBSTS);
writel(n, USB_USBSTS);

/*端口变化探测*/
if (n & STS_PCI) {
msm_hsusb_set_speed(ui);
if (atomic_read(&ui->configured)) {
ui->usb_state = USB_STATE_CONFIGURED;
ui->flags = USB_FLAG_CONFIGURED;
ui->driver->resume(&ui->gadget);
schedule_work(&ui->work);
} else {
msm_hsusb_set_state(USB_STATE_DEFAULT);
}
}
/*usb重启*/
if (n & STS_URI) {
dev_dbg(&ui->pdev->dev, "reset\n");
ui->gadget.speed = USB_SPEED_UNKNOWN;
msm_hsusb_set_state(USB_STATE_DEFAULT);
......................
}
/*usb挂起状态*/
if (n & STS_SLI) {
dev_dbg(&ui->pdev->dev, "suspend\n");
ui->usb_state = USB_STATE_SUSPENDED;
ui->flags = USB_FLAG_SUSPEND;
ui->driver->suspend(&ui->gadget);
schedule_work(&ui->work);
}
/*usb事务传输完成中断*/
if (n & STS_UI) {
n = readl(USB_ENDPTSETUPSTAT);
if (n & EPT_RX(0))
handle_setup(ui);

n = readl(USB_ENDPTCOMPLETE);
writel(n, USB_ENDPTCOMPLETE);
while (n) {
unsigned bit = __ffs(n);
handle_endpoint(ui, bit);
n = n & (~(1 << bit));
}
}
return IRQ_HANDLED;
}