ANDROID: usb: gadget: configfs: Support multiple android instances

Some platforms may choose to create more than one gadget ConfigFS
instance, often due to the hardware having multiple USB gadget
controllers which can be used simultaneously. Currently
android_device_create() assumes only one gadget instance is ever
created and creates a single "android0" device under the "android_usb"
class, resulting in a crash if a second gadget is registered since the
global android_device pointer gets overwritten with -EEXIST.

Fix this by properly supporting multiple instances and naming the
devices "android0", "android1", etc. when each instance is created
(via mkdir). For now keep the global singleton android_device pointing
to android0 for ease of use since f_midi and f_audio_source currently
use create_function_device() without any context as to which gadget
they will be bound to.

Bug: 120441124
Fixes: 429213f5d9eb ("ANDROID: usb: gadget: configfs: Add function devices to the parent")
Signed-off-by: Ajay Agarwal <ajaya@codeaurora.org>
[jackp@codeaurora.org: reworded commit text]
Signed-off-by: Jack Pham <jackp@codeaurora.org>
[sw0312.kim: backport from android common kernel commit 852619242c94 to support multiple udc]
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Change-Id: Iade5973db69a2a4a1800c8218b9f5fba6b59a1c8

diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index 2a8528e..1f21941 100644 (file)
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -26,6 +26,7 @@ void acc_disconnect(void);
 static struct class *android_class;
 static struct device *android_device;
 static int index;
+static int gadget_index;
 
 struct device *create_function_device(char *name)
 {
@@ -1463,15 +1464,13 @@ static void android_work(struct work_struct *data)
        spin_unlock_irqrestore(&cdev->lock, flags);
 
        if (status[0]) {
-               kobject_uevent_env(&android_device->kobj,
-                                       KOBJ_CHANGE, connected);
+               kobject_uevent_env(&gi->dev->kobj, KOBJ_CHANGE, connected);
                pr_info("%s: sent uevent %s\n", __func__, connected[0]);
                uevent_sent = true;
        }
 
        if (status[1]) {
-               kobject_uevent_env(&android_device->kobj,
-                                       KOBJ_CHANGE, configured);
+               kobject_uevent_env(&gi->dev->kobj, KOBJ_CHANGE, configured);
                pr_info("%s: sent uevent %s\n", __func__, configured[0]);
                uevent_sent = true;
 #ifdef CONFIG_AMLOGIC_USB
@@ -1480,8 +1479,7 @@ static void android_work(struct work_struct *data)
        }
 
        if (status[2]) {
-               kobject_uevent_env(&android_device->kobj,
-                                       KOBJ_CHANGE, disconnected);
+               kobject_uevent_env(&gi->dev->kobj, KOBJ_CHANGE, disconnected);
                pr_info("%s: sent uevent %s\n", __func__, disconnected[0]);
                uevent_sent = true;
 #ifdef CONFIG_AMLOGIC_USB
@@ -1753,21 +1751,23 @@ static int android_device_create(struct gadget_info *gi)
        struct device_attribute *attr;
 
        INIT_WORK(&gi->work, android_work);
-       android_device = device_create(android_class, NULL,
-                               MKDEV(0, 0), NULL, "android0");
-       if (IS_ERR(android_device))
-               return PTR_ERR(android_device);
+       gi->dev = device_create(android_class, NULL,
+                       MKDEV(0, 0), NULL, "android%d", gadget_index++);
+       if (IS_ERR(gi->dev))
+               return PTR_ERR(gi->dev);
 
-       dev_set_drvdata(android_device, gi);
+       dev_set_drvdata(gi->dev, gi);
+       if (!android_device)
+               android_device = gi->dev;
 
        attrs = android_usb_attributes;
        while ((attr = *attrs++)) {
                int err;
 
-               err = device_create_file(android_device, attr);
+               err = device_create_file(gi->dev, attr);
                if (err) {
-                       device_destroy(android_device->class,
-                                      android_device->devt);
+                       device_destroy(gi->dev->class,
+                                      gi->dev->devt);
                        return err;
                }
        }
@@ -1775,15 +1775,15 @@ static int android_device_create(struct gadget_info *gi)
        return 0;
 }
 
-static void android_device_destroy(void)
+static void android_device_destroy(struct gadget_info *gi)
 {
        struct device_attribute **attrs;
        struct device_attribute *attr;
 
        attrs = android_usb_attributes;
        while ((attr = *attrs++))
-               device_remove_file(android_device, attr);
-       device_destroy(android_device->class, android_device->devt);
+               device_remove_file(gi->dev, attr);
+       device_destroy(gi->dev->class, gi->dev->devt);
 }
 #else
 static inline int android_device_create(struct gadget_info *gi)
@@ -1791,7 +1791,7 @@ static inline int android_device_create(struct gadget_info *gi)
        return 0;
 }
 
-static inline void android_device_destroy(void)
+static inline void android_device_destroy(struct gadget_info *gi)
 {
 }
 #endif
@@ -1860,8 +1860,11 @@ err:
 
 static void gadgets_drop(struct config_group *group, struct config_item *item)
 {
+       struct gadget_info *gi;
+
+       gi = container_of(to_config_group(item), struct gadget_info, group);
        config_item_put(item);
-       android_device_destroy();
+       android_device_destroy(gi);
 }
 
 static struct configfs_group_operations gadgets_ops = {