Revert "usb: gadget: udc: core: Invoke usb_gadget_connect only when started"

This reverts commit 0db213ea8eed5534a5169e807f28103cbc9d23df.

It introduces an issues with configuring the USB gadget hangs forever
on multiple Qualcomm and NXP i.MX SoC at least.

Cc: stable@vger.kernel.org
Fixes: 0db213ea8eed ("usb: gadget: udc: core: Invoke usb_gadget_connect only when started")
Reported-by: Stephan Gerhold <stephan@gerhold.net>
Reported-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/all/ZF4BvgsOyoKxdPFF@francesco-nb.int.toradex.com/
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/r/20230512131435.205464-3-francesco@dolcini.it
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index 583c339..52e6d2e 100644 (file)
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -37,10 +37,6 @@ static const struct bus_type gadget_bus_type;
  * @vbus: for udcs who care about vbus status, this value is real vbus status;
  * for udcs who do not care about vbus status, this value is always true
  * @started: the UDC's started state. True if the UDC had started.
- * @connect_lock: protects udc->vbus, udc->started, gadget->connect, gadget->deactivate related
- * functions. usb_gadget_connect_locked, usb_gadget_disconnect_locked,
- * usb_udc_connect_control_locked, usb_gadget_udc_start_locked, usb_gadget_udc_stop_locked are
- * called with this lock held.
  *
  * This represents the internal data structure which is used by the UDC-class
  * to hold information about udc driver and gadget together.
@@ -52,7 +48,6 @@ struct usb_udc {
        struct list_head                list;
        bool                            vbus;
        bool                            started;
-       struct mutex                    connect_lock;
 };
 
 static struct class *udc_class;
@@ -692,9 +687,17 @@ out:
 }
 EXPORT_SYMBOL_GPL(usb_gadget_vbus_disconnect);
 
-/* Internal version of usb_gadget_connect needs to be called with connect_lock held. */
-static int usb_gadget_connect_locked(struct usb_gadget *gadget)
-       __must_hold(&gadget->udc->connect_lock)
+/**
+ * usb_gadget_connect - software-controlled connect to USB host
+ * @gadget:the peripheral being connected
+ *
+ * Enables the D+ (or potentially D-) pullup.  The host will start
+ * enumerating this gadget when the pullup is active and a VBUS session
+ * is active (the link is powered).
+ *
+ * Returns zero on success, else negative errno.
+ */
+int usb_gadget_connect(struct usb_gadget *gadget)
 {
        int ret = 0;
 
@@ -703,12 +706,10 @@ static int usb_gadget_connect_locked(struct usb_gadget *gadget)
                goto out;
        }
 
-       if (gadget->deactivated || !gadget->udc->started) {
+       if (gadget->deactivated) {
                /*
                 * If gadget is deactivated we only save new state.
                 * Gadget will be connected automatically after activation.
-                *
-                * udc first needs to be started before gadget can be pulled up.
                 */
                gadget->connected = true;
                goto out;
@@ -723,32 +724,22 @@ out:
 
        return ret;
 }
+EXPORT_SYMBOL_GPL(usb_gadget_connect);
 
 /**
- * usb_gadget_connect - software-controlled connect to USB host
- * @gadget:the peripheral being connected
+ * usb_gadget_disconnect - software-controlled disconnect from USB host
+ * @gadget:the peripheral being disconnected
  *
- * Enables the D+ (or potentially D-) pullup.  The host will start
- * enumerating this gadget when the pullup is active and a VBUS session
- * is active (the link is powered).
+ * Disables the D+ (or potentially D-) pullup, which the host may see
+ * as a disconnect (when a VBUS session is active).  Not all systems
+ * support software pullup controls.
+ *
+ * Following a successful disconnect, invoke the ->disconnect() callback
+ * for the current gadget driver so that UDC drivers don't need to.
  *
  * Returns zero on success, else negative errno.
  */
-int usb_gadget_connect(struct usb_gadget *gadget)
-{
-       int ret;
-
-       mutex_lock(&gadget->udc->connect_lock);
-       ret = usb_gadget_connect_locked(gadget);
-       mutex_unlock(&gadget->udc->connect_lock);
-
-       return ret;
-}
-EXPORT_SYMBOL_GPL(usb_gadget_connect);
-
-/* Internal version of usb_gadget_disconnect needs to be called with connect_lock held. */
-static int usb_gadget_disconnect_locked(struct usb_gadget *gadget)
-       __must_hold(&gadget->udc->connect_lock)
+int usb_gadget_disconnect(struct usb_gadget *gadget)
 {
        int ret = 0;
 
@@ -760,12 +751,10 @@ static int usb_gadget_disconnect_locked(struct usb_gadget *gadget)
        if (!gadget->connected)
                goto out;
 
-       if (gadget->deactivated || !gadget->udc->started) {
+       if (gadget->deactivated) {
                /*
                 * If gadget is deactivated we only save new state.
                 * Gadget will stay disconnected after activation.
-                *
-                * udc should have been started before gadget being pulled down.
                 */
                gadget->connected = false;
                goto out;
@@ -785,30 +774,6 @@ out:
 
        return ret;
 }
-
-/**
- * usb_gadget_disconnect - software-controlled disconnect from USB host
- * @gadget:the peripheral being disconnected
- *
- * Disables the D+ (or potentially D-) pullup, which the host may see
- * as a disconnect (when a VBUS session is active).  Not all systems
- * support software pullup controls.
- *
- * Following a successful disconnect, invoke the ->disconnect() callback
- * for the current gadget driver so that UDC drivers don't need to.
- *
- * Returns zero on success, else negative errno.
- */
-int usb_gadget_disconnect(struct usb_gadget *gadget)
-{
-       int ret;
-
-       mutex_lock(&gadget->udc->connect_lock);
-       ret = usb_gadget_disconnect_locked(gadget);
-       mutex_unlock(&gadget->udc->connect_lock);
-
-       return ret;
-}
 EXPORT_SYMBOL_GPL(usb_gadget_disconnect);
 
 /**
@@ -829,11 +794,10 @@ int usb_gadget_deactivate(struct usb_gadget *gadget)
        if (gadget->deactivated)
                goto out;
 
-       mutex_lock(&gadget->udc->connect_lock);
        if (gadget->connected) {
-               ret = usb_gadget_disconnect_locked(gadget);
+               ret = usb_gadget_disconnect(gadget);
                if (ret)
-                       goto unlock;
+                       goto out;
 
                /*
                 * If gadget was being connected before deactivation, we want
@@ -843,8 +807,6 @@ int usb_gadget_deactivate(struct usb_gadget *gadget)
        }
        gadget->deactivated = true;
 
-unlock:
-       mutex_unlock(&gadget->udc->connect_lock);
 out:
        trace_usb_gadget_deactivate(gadget, ret);
 
@@ -868,7 +830,6 @@ int usb_gadget_activate(struct usb_gadget *gadget)
        if (!gadget->deactivated)
                goto out;
 
-       mutex_lock(&gadget->udc->connect_lock);
        gadget->deactivated = false;
 
        /*
@@ -876,8 +837,7 @@ int usb_gadget_activate(struct usb_gadget *gadget)
         * while it was being deactivated, we call usb_gadget_connect().
         */
        if (gadget->connected)
-               ret = usb_gadget_connect_locked(gadget);
-       mutex_unlock(&gadget->udc->connect_lock);
+               ret = usb_gadget_connect(gadget);
 
 out:
        trace_usb_gadget_activate(gadget, ret);
@@ -1118,13 +1078,12 @@ EXPORT_SYMBOL_GPL(usb_gadget_set_state);
 
 /* ------------------------------------------------------------------------- */
 
-/* Acquire connect_lock before calling this function. */
-static void usb_udc_connect_control_locked(struct usb_udc *udc) __must_hold(&udc->connect_lock)
+static void usb_udc_connect_control(struct usb_udc *udc)
 {
-       if (udc->vbus && udc->started)
-               usb_gadget_connect_locked(udc->gadget);
+       if (udc->vbus)
+               usb_gadget_connect(udc->gadget);
        else
-               usb_gadget_disconnect_locked(udc->gadget);
+               usb_gadget_disconnect(udc->gadget);
 }
 
 /**
@@ -1140,12 +1099,10 @@ void usb_udc_vbus_handler(struct usb_gadget *gadget, bool status)
 {
        struct usb_udc *udc = gadget->udc;
 
-       mutex_lock(&udc->connect_lock);
        if (udc) {
                udc->vbus = status;
-               usb_udc_connect_control_locked(udc);
+               usb_udc_connect_control(udc);
        }
-       mutex_unlock(&udc->connect_lock);
 }
 EXPORT_SYMBOL_GPL(usb_udc_vbus_handler);
 
@@ -1167,7 +1124,7 @@ void usb_gadget_udc_reset(struct usb_gadget *gadget,
 EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);
 
 /**
- * usb_gadget_udc_start_locked - tells usb device controller to start up
+ * usb_gadget_udc_start - tells usb device controller to start up
  * @udc: The UDC to be started
  *
  * This call is issued by the UDC Class driver when it's about
@@ -1178,11 +1135,8 @@ EXPORT_SYMBOL_GPL(usb_gadget_udc_reset);
  * necessary to have it powered on.
  *
  * Returns zero on success, else negative errno.
- *
- * Caller should acquire connect_lock before invoking this function.
  */
-static inline int usb_gadget_udc_start_locked(struct usb_udc *udc)
-       __must_hold(&udc->connect_lock)
+static inline int usb_gadget_udc_start(struct usb_udc *udc)
 {
        int ret;
 
@@ -1199,7 +1153,7 @@ static inline int usb_gadget_udc_start_locked(struct usb_udc *udc)
 }
 
 /**
- * usb_gadget_udc_stop_locked - tells usb device controller we don't need it anymore
+ * usb_gadget_udc_stop - tells usb device controller we don't need it anymore
  * @udc: The UDC to be stopped
  *
  * This call is issued by the UDC Class driver after calling
@@ -1208,11 +1162,8 @@ static inline int usb_gadget_udc_start_locked(struct usb_udc *udc)
  * The details are implementation specific, but it can go as
  * far as powering off UDC completely and disable its data
  * line pullups.
- *
- * Caller should acquire connect lock before invoking this function.
  */
-static inline void usb_gadget_udc_stop_locked(struct usb_udc *udc)
-       __must_hold(&udc->connect_lock)
+static inline void usb_gadget_udc_stop(struct usb_udc *udc)
 {
        if (!udc->started) {
                dev_err(&udc->dev, "UDC had already stopped\n");
@@ -1371,7 +1322,6 @@ int usb_add_gadget(struct usb_gadget *gadget)
 
        udc->gadget = gadget;
        gadget->udc = udc;
-       mutex_init(&udc->connect_lock);
 
        udc->started = false;
 
@@ -1573,15 +1523,11 @@ static int gadget_bind_driver(struct device *dev)
        if (ret)
                goto err_bind;
 
-       mutex_lock(&udc->connect_lock);
-       ret = usb_gadget_udc_start_locked(udc);
-       if (ret) {
-               mutex_unlock(&udc->connect_lock);
+       ret = usb_gadget_udc_start(udc);
+       if (ret)
                goto err_start;
-       }
        usb_gadget_enable_async_callbacks(udc);
-       usb_udc_connect_control_locked(udc);
-       mutex_unlock(&udc->connect_lock);
+       usb_udc_connect_control(udc);
 
        kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
        return 0;
@@ -1612,14 +1558,12 @@ static void gadget_unbind_driver(struct device *dev)
 
        kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
 
-       mutex_lock(&udc->connect_lock);
-       usb_gadget_disconnect_locked(gadget);
+       usb_gadget_disconnect(gadget);
        usb_gadget_disable_async_callbacks(udc);
        if (gadget->irq)
                synchronize_irq(gadget->irq);
        udc->driver->unbind(gadget);
-       usb_gadget_udc_stop_locked(udc);
-       mutex_unlock(&udc->connect_lock);
+       usb_gadget_udc_stop(udc);
 
        mutex_lock(&udc_lock);
        driver->is_bound = false;
@@ -1705,15 +1649,11 @@ static ssize_t soft_connect_store(struct device *dev,
        }
 
        if (sysfs_streq(buf, "connect")) {
-               mutex_lock(&udc->connect_lock);
-               usb_gadget_udc_start_locked(udc);
-               usb_gadget_connect_locked(udc->gadget);
-               mutex_unlock(&udc->connect_lock);
+               usb_gadget_udc_start(udc);
+               usb_gadget_connect(udc->gadget);
        } else if (sysfs_streq(buf, "disconnect")) {
-               mutex_lock(&udc->connect_lock);
-               usb_gadget_disconnect_locked(udc->gadget);
-               usb_gadget_udc_stop_locked(udc);
-               mutex_unlock(&udc->connect_lock);
+               usb_gadget_disconnect(udc->gadget);
+               usb_gadget_udc_stop(udc);
        } else {
                dev_err(dev, "unsupported command '%s'\n", buf);
                ret = -EINVAL;