android-5.4/ANDROID-usb-gadget-configfs-Add-Uevent-to-notify-userspace.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Badhri Jagan Sridharan <Badhri@google.com>
Date: Mon, 15 Dec 2014 10:44:47 -0800
Subject: ANDROID: usb: gadget: configfs: Add Uevent to notify userspace

Android userspace UsbDeviceManager relies on the
uevents generated by the composition driver to
generate user notifications. This CL adds uevents
to be generated whenever USB changes its state
i.e. connected, disconnected, configured.

This CL also intercepts the setup requests from
the usb_core anb routes it to the specific
usb function if required.

Bug: 68755607
Bug: 120441124
Change-Id: Ib3d3a78255a532f7449dac286f776c2966caf8c1
[badhri: Migrate to using udc uevents from upstream sysfs.]
Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
[AmitP: Folded following android-4.9 commit changes into this patch
        9214c899f730 ("ANDROID: usb: gadget: configfs: handle gadget reset request for android")]
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
[adelva: Folded change 5c899c9fd75d ("ANDROID: usb: gadget: configfs:
         fix null ptr in android_disconnect") into this patch]
Signed-off-by: Alistair Delva <adelva@google.com>
[maennich: Folded change 43e98b082f9e ("ANDROID: usb: gadget: configfs:
           fix compiler warning") into this patch]
Signed-off-by: Matthias Maennich <maennich@google.com>
---
 drivers/usb/gadget/Kconfig    |   8 ++
 drivers/usb/gadget/configfs.c | 168 +++++++++++++++++++++++++++++++++-
 2 files changed, 174 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 02ff850278b1..f5e82dcac583 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -230,6 +230,14 @@ config USB_CONFIGFS
 	  appropriate symbolic links.
 	  For more information see Documentation/usb/gadget_configfs.rst.
 
+config USB_CONFIGFS_UEVENT
+	bool "Uevent notification of Gadget state"
+	depends on USB_CONFIGFS
+	help
+	  Enable uevent notifications to userspace when the gadget
+	  state changes. The gadget can be in any of the following
+	  three states: "CONNECTED/DISCONNECTED/CONFIGURED"
+
 config USB_CONFIGFS_SERIAL
 	bool "Generic serial bulk in/out"
 	depends on USB_CONFIGFS
diff --git a/drivers/usb/gadget/configfs.c b/drivers/usb/gadget/configfs.c
index ab9ac48a751a..51007d9adf0c 100644
--- a/drivers/usb/gadget/configfs.c
+++ b/drivers/usb/gadget/configfs.c
@@ -10,6 +10,19 @@
 #include "u_f.h"
 #include "u_os_desc.h"
 
+#ifdef CONFIG_USB_CONFIGFS_UEVENT
+#include <linux/platform_device.h>
+#include <linux/kdev_t.h>
+#include <linux/usb/ch9.h>
+
+#ifdef CONFIG_USB_CONFIGFS_F_ACC
+extern int acc_ctrlrequest(struct usb_composite_dev *cdev,
+				const struct usb_ctrlrequest *ctrl);
+void acc_disconnect(void);
+#endif
+static struct class *android_class;
+#endif
+
 int check_user_usb_string(const char *name,
 		struct usb_gadget_strings *stringtab_dev)
 {
@@ -63,6 +76,12 @@ struct gadget_info {
 	char qw_sign[OS_STRING_QW_SIGN_LEN];
 	spinlock_t spinlock;
 	bool unbind;
+#ifdef CONFIG_USB_CONFIGFS_UEVENT
+	bool connected;
+	bool sw_connected;
+	struct work_struct work;
+	struct device *dev;
+#endif
 };
 
 static inline struct gadget_info *to_gadget_info(struct config_item *item)
@@ -268,7 +287,7 @@ static ssize_t gadget_dev_desc_UDC_store(struct config_item *item,
 
 	mutex_lock(&gi->lock);
 
-	if (!strlen(name)) {
+	if (!strlen(name) || strcmp(name, "none") == 0) {
 		ret = unregister_gadget(gi);
 		if (ret)
 			goto err;
@@ -1375,6 +1394,57 @@ static int configfs_composite_bind(struct usb_gadget *gadget,
 	return ret;
 }
 
+#ifdef CONFIG_USB_CONFIGFS_UEVENT
+static void android_work(struct work_struct *data)
+{
+	struct gadget_info *gi = container_of(data, struct gadget_info, work);
+	struct usb_composite_dev *cdev = &gi->cdev;
+	char *disconnected[2] = { "USB_STATE=DISCONNECTED", NULL };
+	char *connected[2]    = { "USB_STATE=CONNECTED", NULL };
+	char *configured[2]   = { "USB_STATE=CONFIGURED", NULL };
+	/* 0-connected 1-configured 2-disconnected*/
+	bool status[3] = { false, false, false };
+	unsigned long flags;
+	bool uevent_sent = false;
+
+	spin_lock_irqsave(&cdev->lock, flags);
+	if (cdev->config)
+		status[1] = true;
+
+	if (gi->connected != gi->sw_connected) {
+		if (gi->connected)
+			status[0] = true;
+		else
+			status[2] = true;
+		gi->sw_connected = gi->connected;
+	}
+	spin_unlock_irqrestore(&cdev->lock, flags);
+
+	if (status[0]) {
+		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(&gi->dev->kobj, KOBJ_CHANGE, configured);
+		pr_info("%s: sent uevent %s\n", __func__, configured[0]);
+		uevent_sent = true;
+	}
+
+	if (status[2]) {
+		kobject_uevent_env(&gi->dev->kobj, KOBJ_CHANGE, disconnected);
+		pr_info("%s: sent uevent %s\n", __func__, disconnected[0]);
+		uevent_sent = true;
+	}
+
+	if (!uevent_sent) {
+		pr_info("%s: did not send uevent (%d %d %p)\n", __func__,
+			gi->connected, gi->sw_connected, cdev->config);
+	}
+}
+#endif
+
 static void configfs_composite_unbind(struct usb_gadget *gadget)
 {
 	struct usb_composite_dev	*cdev;
@@ -1400,6 +1470,80 @@ static void configfs_composite_unbind(struct usb_gadget *gadget)
 	spin_unlock_irqrestore(&gi->spinlock, flags);
 }
 
+#ifdef CONFIG_USB_CONFIGFS_UEVENT
+static int android_setup(struct usb_gadget *gadget,
+			const struct usb_ctrlrequest *c)
+{
+	struct usb_composite_dev *cdev = get_gadget_data(gadget);
+	unsigned long flags;
+	struct gadget_info *gi = container_of(cdev, struct gadget_info, cdev);
+	int value = -EOPNOTSUPP;
+	struct usb_function_instance *fi;
+
+	spin_lock_irqsave(&cdev->lock, flags);
+	if (!gi->connected) {
+		gi->connected = 1;
+		schedule_work(&gi->work);
+	}
+	spin_unlock_irqrestore(&cdev->lock, flags);
+	list_for_each_entry(fi, &gi->available_func, cfs_list) {
+		if (fi != NULL && fi->f != NULL && fi->f->setup != NULL) {
+			value = fi->f->setup(fi->f, c);
+			if (value >= 0)
+				break;
+		}
+	}
+
+#ifdef CONFIG_USB_CONFIGFS_F_ACC
+	if (value < 0)
+		value = acc_ctrlrequest(cdev, c);
+#endif
+
+	if (value < 0)
+		value = composite_setup(gadget, c);
+
+	spin_lock_irqsave(&cdev->lock, flags);
+	if (c->bRequest == USB_REQ_SET_CONFIGURATION &&
+						cdev->config) {
+		schedule_work(&gi->work);
+	}
+	spin_unlock_irqrestore(&cdev->lock, flags);
+
+	return value;
+}
+
+static void android_disconnect(struct usb_gadget *gadget)
+{
+	struct usb_composite_dev        *cdev = get_gadget_data(gadget);
+	struct gadget_info *gi = container_of(cdev, struct gadget_info, cdev);
+
+	/* FIXME: There's a race between usb_gadget_udc_stop() which is likely
+	 * to set the gadget driver to NULL in the udc driver and this drivers
+	 * gadget disconnect fn which likely checks for the gadget driver to
+	 * be a null ptr. It happens that unbind (doing set_gadget_data(NULL))
+	 * is called before the gadget driver is set to NULL and the udc driver
+	 * calls disconnect fn which results in cdev being a null ptr.
+	 */
+	if (cdev == NULL) {
+		WARN(1, "%s: gadget driver already disconnected\n", __func__);
+		return;
+	}
+
+	/* accessory HID support can be active while the
+		accessory function is not actually enabled,
+		so we need to inform it when we are disconnected.
+	*/
+
+#ifdef CONFIG_USB_CONFIGFS_F_ACC
+	acc_disconnect();
+#endif
+	gi->connected = 0;
+	schedule_work(&gi->work);
+	composite_disconnect(gadget);
+}
+
+#else // CONFIG_USB_CONFIGFS_UEVENT
+
 static int configfs_composite_setup(struct usb_gadget *gadget,
 		const struct usb_ctrlrequest *ctrl)
 {
@@ -1447,6 +1591,8 @@ static void configfs_composite_disconnect(struct usb_gadget *gadget)
 	spin_unlock_irqrestore(&gi->spinlock, flags);
 }
 
+#endif // CONFIG_USB_CONFIGFS_UEVENT
+
 static void configfs_composite_suspend(struct usb_gadget *gadget)
 {
 	struct usb_composite_dev *cdev;
@@ -1495,10 +1641,15 @@ static const struct usb_gadget_driver configfs_driver_template = {
 	.bind           = configfs_composite_bind,
 	.unbind         = configfs_composite_unbind,
 
+#ifdef CONFIG_USB_CONFIGFS_UEVENT
+	.setup          = android_setup,
+	.reset          = android_disconnect,
+	.disconnect     = android_disconnect,
+#else
 	.setup          = configfs_composite_setup,
 	.reset          = configfs_composite_disconnect,
 	.disconnect     = configfs_composite_disconnect,
-
+#endif
 	.suspend	= configfs_composite_suspend,
 	.resume		= configfs_composite_resume,
 
@@ -1559,6 +1710,12 @@ static struct config_group *gadgets_make(
 	gi->composite.gadget_driver.function = kstrdup(name, GFP_KERNEL);
 	gi->composite.name = gi->composite.gadget_driver.function;
 
+#ifdef CONFIG_USB_CONFIGFS_UEVENT
+	INIT_WORK(&gi->work, android_work);
+	gi->dev = device_create(android_class, NULL,
+				MKDEV(0, 0), NULL, "android0");
+#endif
+
 	if (!gi->composite.gadget_driver.function)
 		goto err;
 
@@ -1610,6 +1767,13 @@ static int __init gadget_cfs_init(void)
 	config_group_init(&gadget_subsys.su_group);
 
 	ret = configfs_register_subsystem(&gadget_subsys);
+
+#ifdef CONFIG_USB_CONFIGFS_UEVENT
+	android_class = class_create(THIS_MODULE, "android_usb");
+	if (IS_ERR(android_class))
+		return PTR_ERR(android_class);
+#endif
+
 	return ret;
 }
 module_init(gadget_cfs_init);