[RFC][PATCH 2/9] usb: gadget: add usb_gadget_start/stop()
From: Roger Quadros
Date: Wed Mar 18 2015 - 09:58:58 EST
The OTG state machine needs a mechanism to start and
stop the gadget controller. Add usb_gadget_start()
and usb_gadget_stop().
Signed-off-by: Roger Quadros <rogerq@xxxxxx>
---
drivers/usb/gadget/udc/udc-core.c | 166 +++++++++++++++++++++++++++++++++++---
include/linux/usb/gadget.h | 3 +
2 files changed, 158 insertions(+), 11 deletions(-)
diff --git a/drivers/usb/gadget/udc/udc-core.c b/drivers/usb/gadget/udc/udc-core.c
index 5a81cb0..69b4123 100644
--- a/drivers/usb/gadget/udc/udc-core.c
+++ b/drivers/usb/gadget/udc/udc-core.c
@@ -35,6 +35,8 @@
* @dev - the child device to the actual controller
* @gadget - the gadget. For use by the class code
* @list - for use by the udc class driver
+ * @running - udc is running
+ * @softconnect - sysfs softconnect says OK to connect
*
* This represents the internal data structure which is used by the UDC-class
* to hold information about udc driver and gadget together.
@@ -44,6 +46,8 @@ struct usb_udc {
struct usb_gadget *gadget;
struct device dev;
struct list_head list;
+ bool running;
+ bool softconnect;
};
static struct class *udc_class;
@@ -187,7 +191,14 @@ EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);
*/
static inline int usb_gadget_udc_start(struct usb_udc *udc)
{
- return udc->gadget->ops->udc_start(udc->gadget, udc->driver);
+ int ret;
+
+ dev_dbg(&udc->dev, "%s\n", __func__);
+ ret = udc->gadget->ops->udc_start(udc->gadget, udc->driver);
+ if (!ret)
+ udc->running = 1;
+
+ return ret;
}
/**
@@ -204,10 +215,140 @@ static inline int usb_gadget_udc_start(struct usb_udc *udc)
*/
static inline void usb_gadget_udc_stop(struct usb_udc *udc)
{
+ dev_dbg(&udc->dev, "%s\n", __func__);
udc->gadget->ops->udc_stop(udc->gadget);
+ udc->running = 0;
}
/**
+ * usb_udc_start - Start the usb device controller only if conditions met
+ * @udc: The UDC to be started
+ *
+ * Start the UDC and connect to bus (enable pull) only if the
+ * following conditions are met
+ * - UDC is not already running
+ * - gadget function driver is loaded
+ * - userspace softconnect says OK to connect
+ *
+ * NOTE: udc_lock must be held by caller.
+ *
+ * Returs 0 on success or not ready to start, else negative errno.
+ */
+static int usb_udc_start(struct usb_udc *udc)
+{
+ int ret;
+
+ if (udc->running) {
+ dev_err(&udc->dev, "%s: not starting as already running\n",
+ __func__);
+ return -EBUSY;
+ }
+
+ if (udc->driver && udc->softconnect) {
+ ret = usb_gadget_udc_start(udc);
+ if (ret)
+ return ret;
+
+ usb_gadget_connect(udc->gadget);
+ }
+
+ return 0;
+}
+
+/**
+ * usb_udc_stop - Stop the usb device controller
+ * @udc: The UDC to be stopped
+ *
+ * Disconnect from bus (disable pull) and stop the UDC.
+ *
+ * NOTE: udc_lock must be held by caller.
+ *
+ * Returs 0 on success, else negative errno.
+ */
+static int usb_udc_stop(struct usb_udc *udc)
+{
+ if (!udc->running) {
+ dev_err(&udc->dev, "%s: not stopping as already halted\n",
+ __func__);
+ return -EBUSY;
+ }
+
+ usb_gadget_disconnect(udc->gadget);
+ udc->driver->disconnect(udc->gadget);
+ usb_gadget_udc_stop(udc);
+
+ return 0;
+}
+
+/**
+ * usb_gadget_start - start the usb gadget controller
+ * @gadget: the gadget device to start
+ *
+ * This is external API for use by OTG core.
+ *
+ * Start the usb device controller and connect to bus (enable pull).
+ * There is no guarantee that the controller is started
+ * as we might be missing some dependencies
+ * i.e. gadget function driver not loaded or softconnect disabled.
+ */
+int usb_gadget_start(struct usb_gadget *gadget)
+{
+ int ret;
+ struct usb_udc *udc = NULL;
+
+ dev_dbg(&gadget->dev, "%s\n", __func__);
+ mutex_lock(&udc_lock);
+ list_for_each_entry(udc, &udc_list, list)
+ if (udc->gadget == gadget)
+ goto found;
+
+ dev_err(gadget->dev.parent, "%s: gadget not registered.\n",
+ __func__);
+ mutex_unlock(&udc_lock);
+ return -EINVAL;
+
+found:
+ ret = usb_udc_start(udc);
+ mutex_unlock(&udc_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_start);
+
+/**
+ * usb_gadget_stop - stop the usb gadget
+ * @gadget: The gadget device we want to stop
+ *
+ * This is external API for use by OTG core.
+ *
+ * Disconnect from the bus (disable pull) and stop the
+ * gadget controller.
+ */
+int usb_gadget_stop(struct usb_gadget *gadget)
+{
+ int ret;
+ struct usb_udc *udc = NULL;
+
+ dev_dbg(&gadget->dev, "%s\n", __func__);
+ mutex_lock(&udc_lock);
+ list_for_each_entry(udc, &udc_list, list)
+ if (udc->gadget == gadget)
+ goto found;
+
+ dev_err(gadget->dev.parent, "%s: gadget not registered.\n",
+ __func__);
+ mutex_unlock(&udc_lock);
+ return -EINVAL;
+
+found:
+ ret = usb_udc_stop(udc);
+ mutex_unlock(&udc_lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_gadget_stop);
+
+/**
* usb_udc_release - release the usb_udc struct
* @dev: the dev member within usb_udc
*
@@ -278,6 +419,7 @@ int usb_add_gadget_udc_release(struct device *parent, struct usb_gadget *gadget,
goto err3;
udc->gadget = gadget;
+ udc->softconnect = 1; /* connect by default */
mutex_lock(&udc_lock);
list_add_tail(&udc->list, &udc_list);
@@ -329,10 +471,8 @@ static void usb_gadget_remove_driver(struct usb_udc *udc)
kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
- usb_gadget_disconnect(udc->gadget);
- udc->driver->disconnect(udc->gadget);
+ usb_udc_stop(udc);
udc->driver->unbind(udc->gadget);
- usb_gadget_udc_stop(udc);
udc->driver = NULL;
udc->dev.driver = NULL;
@@ -378,6 +518,7 @@ EXPORT_SYMBOL_GPL(usb_del_gadget_udc);
/* ------------------------------------------------------------------------- */
+/* udc_lock must be held */
static int udc_bind_to_driver(struct usb_udc *udc, struct usb_gadget_driver *driver)
{
int ret;
@@ -392,12 +533,12 @@ static int udc_bind_to_driver(struct usb_udc *udc, struct usb_gadget_driver *dri
ret = driver->bind(udc->gadget, driver);
if (ret)
goto err1;
- ret = usb_gadget_udc_start(udc);
+
+ ret = usb_udc_start(udc);
if (ret) {
driver->unbind(udc->gadget);
goto err1;
}
- usb_gadget_connect(udc->gadget);
kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
return 0;
@@ -510,12 +651,15 @@ static ssize_t usb_udc_softconn_store(struct device *dev,
}
if (sysfs_streq(buf, "connect")) {
- usb_gadget_udc_start(udc);
- usb_gadget_connect(udc->gadget);
+ mutex_lock(&udc_lock);
+ udc->softconnect = 1;
+ usb_udc_start(udc);
+ mutex_unlock(&udc_lock);
} else if (sysfs_streq(buf, "disconnect")) {
- usb_gadget_disconnect(udc->gadget);
- udc->driver->disconnect(udc->gadget);
- usb_gadget_udc_stop(udc);
+ mutex_lock(&udc_lock);
+ udc->softconnect = 0;
+ usb_udc_stop(udc);
+ mutex_unlock(&udc_lock);
} else {
dev_err(dev, "unsupported command '%s'\n", buf);
return -EINVAL;
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index e2f00fd..7ada7e6 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -922,6 +922,9 @@ int usb_gadget_probe_driver(struct usb_gadget_driver *driver);
*/
int usb_gadget_unregister_driver(struct usb_gadget_driver *driver);
+int usb_gadget_start(struct usb_gadget *gadget);
+int usb_gadget_stop(struct usb_gadget *gadget);
+
extern int usb_add_gadget_udc_release(struct device *parent,
struct usb_gadget *gadget, void (*release)(struct device *dev));
extern int usb_add_gadget_udc(struct device *parent, struct usb_gadget *gadget);
--
2.1.0
--
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