ANDROID: usb: gadget: Add support for MTP OS desc

Windows requires OS specific descriptors for automatic
install of drivers for MTP devices.

https://msdn.microsoft.com/en-us/library/windows/
hardware/gg463179.aspx

BUG=24583401
BUG=chrome-os-partner:43409

Change-Id: I9397072ca3d183efbc9571c6cde3790f10d8851e
Signed-off-by: Badhri Jagan Sridharan <Badhri@google.com>
Reviewed-on: https://chromium-review.googlesource.com/304346
Commit-Ready: Andrew Bresticker <abrestic@chromium.org>
Tested-by: Andrew Bresticker <abrestic@chromium.org>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>

diff --git a/drivers/usb/gadget/function/f_mtp.c b/drivers/usb/gadget/function/f_mtp.c
index 7f5c390885feb7bba8cd90505cb92e4397fa0302..74195be9b054ae4f547fd526615a9ba8d917677c 100644 (file)
--- a/drivers/usb/gadget/function/f_mtp.c
+++ b/drivers/usb/gadget/function/f_mtp.c
@@ -346,6 +346,8 @@ struct mtp_instance {
        struct usb_function_instance func_inst;
        const char *name;
        struct mtp_dev *dev;
+       char mtp_ext_compat_id[16];
+       struct usb_os_desc mtp_os_desc;
 };
 
 /* temporary variable used between mtp_open() and mtp_gadget_bind() */
@@ -1157,6 +1159,7 @@ mtp_function_bind(struct usb_configuration *c, struct usb_function *f)
        struct mtp_dev  *dev = func_to_mtp(f);
        int                     id;
        int                     ret;
+       struct mtp_instance *fi_mtp;
 
        dev->cdev = cdev;
        DBG(cdev, "mtp_function_bind dev: %p\n", dev);
@@ -1174,6 +1177,18 @@ mtp_function_bind(struct usb_configuration *c, struct usb_function *f)
                mtp_string_defs[INTERFACE_STRING_INDEX].id = ret;
                mtp_interface_desc.iInterface = ret;
        }
+
+       fi_mtp = container_of(f->fi, struct mtp_instance, func_inst);
+
+       if (cdev->use_os_string) {
+               f->os_desc_table = kzalloc(sizeof(*f->os_desc_table),
+                                       GFP_KERNEL);
+               if (!f->os_desc_table)
+                       return -ENOMEM;
+               f->os_desc_n = 1;
+               f->os_desc_table[0].os_desc = &fi_mtp->mtp_os_desc;
+       }
+
        /* allocate endpoints */
        ret = mtp_create_bulk_endpoints(dev, &mtp_fullspeed_in_desc,
                        &mtp_fullspeed_out_desc, &mtp_intr_desc);
@@ -1223,6 +1238,8 @@ mtp_function_unbind(struct usb_configuration *c, struct usb_function *f)
        while ((req = mtp_req_get(dev, &dev->intr_idle)))
                mtp_request_free(req, dev->ep_intr);
        dev->state = STATE_OFFLINE;
+       kfree(f->os_desc_table);
+       f->os_desc_n = 0;
 }
 
 static int mtp_function_set_alt(struct usb_function *f,
@@ -1406,6 +1423,7 @@ static void mtp_free_inst(struct usb_function_instance *fi)
        fi_mtp = to_fi_mtp(fi);
        kfree(fi_mtp->name);
        mtp_cleanup();
+       kfree(fi_mtp->mtp_os_desc.group.default_groups);
        kfree(fi_mtp);
 }
 
@@ -1413,6 +1431,8 @@ struct usb_function_instance *alloc_inst_mtp_ptp(bool mtp_config)
 {
        struct mtp_instance *fi_mtp;
        int ret = 0;
+       struct usb_os_desc *descs[1];
+       char *names[1];
 
        fi_mtp = kzalloc(sizeof(*fi_mtp), GFP_KERNEL);
        if (!fi_mtp)
@@ -1420,6 +1440,13 @@ struct usb_function_instance *alloc_inst_mtp_ptp(bool mtp_config)
        fi_mtp->func_inst.set_inst_name = mtp_set_inst_name;
        fi_mtp->func_inst.free_func_inst = mtp_free_inst;
 
+       fi_mtp->mtp_os_desc.ext_compat_id = fi_mtp->mtp_ext_compat_id;
+       INIT_LIST_HEAD(&fi_mtp->mtp_os_desc.ext_prop);
+       descs[0] = &fi_mtp->mtp_os_desc;
+       names[0] = "MTP";
+       usb_os_desc_prepare_interf_dir(&fi_mtp->func_inst.group, 1,
+                                       descs, names, THIS_MODULE);
+
        if (mtp_config) {
                ret = mtp_setup_configfs(fi_mtp);
                if (ret) {