Have you tried with the config CONFIG_USB_G_ANDROID but not
CONFIG_USB_FUNCTIONFS. The android.c will include f_fs.c to support the adb
over usb functionfs. Or the since 3.14, it does not support use G_ANDROID
to control all android related gadget functin?
On Wednesday, March 18, 2015 at 7:14:52 AM UTC+8, Amit Pundir wrote:
>
> Hi,
>
> On 4 March 2015 at 07:09, Guoyin Chen <guoyi...@gmail.com <javascript:>>
> wrote:
> > I am trying to use the branch linux-linaro-lsk-v3.14-android from Linaro
> or
> > android-3.14 from AOSP. It seems the adb cannot work with f_fs.c driver.
> >
>
> It's been a while but ADB over FunctionFS worked for me with
> linux-linaro-lsk-v3.14-android and I don't see any reason why it
> shouldn't work with android-3.14 as such.
>
> Here are the set of instructions which worked for me:
>
> 1) Enable FunctionFS in kernel, "Device Drivers -> USB Support -> USB
> Gadget Support -> USB Gadget Driver -> Function Filesystem" and boot
> with this additional bootarg "g_ffs.idVendor=0x18d1".
>
> 2) Run following commands from Android shell:
> $ su
> # stop adbd
> # mkdir /dev/usb-ffs
> # mkdir /dev/usb-ffs/adb
> # mount -o uid=2000,gid=2000 -t functionfs adb /dev/usb-ffs/adb
> # start adbd
>
> 3) Run adb shell from host computer to verify.
>
> The trick above is that the adb FunctionFS mount path
> "/dev/usb-ffs/adb" and set of supported VendorIDs e.g
> "g_ffs.idVendor=0x18d1" are hardcoded in adbd. So we can not just set
> any random path/values there.
>
> Regards,
> Amit Pundir
>
> > Every time, you try the commands "mount -o uid=2000,gid=2000 -t
> functionfs
> > adb /dev/usb-ffs/adb", it will failed on no device found.
> >
> > in the function ffs_fs_mount(), it will try to look up a ffs_dev with
> the
> > name "adb". But the android gadget driver, there is not code to register
> > such device to f_fs.
> >
> > In 3.10 kernel, the ffs_fs_mount() will worked even with a null ffs_dev
> > returned by functionfs_acquire_dev_callback(dev_name), which defined in
> > android.c.
> >
> > Should we have some code in android gadget driver to init a adb ffs_dev
> as
> > the one in g_ffs driver's gfs_init()? Or any better way to add adb
> ffs_dev?
> >
> > 3.10 kernel:
> > /* "mount -t functionfs dev_name /dev/function" ends up here */
> >
> > static struct dentry *
> > ffs_fs_mount(struct file_system_type *t, int flags,
> > const char *dev_name, void *opts)
> > {
> > struct ffs_sb_fill_data data = {
> > .perms = {
> > .mode = S_IFREG | 0600,
> > .uid = GLOBAL_ROOT_UID,
> > .gid = GLOBAL_ROOT_GID,
> > },
> > .root_mode = S_IFDIR | 0500,
> > };
> > struct dentry *rv;
> > int ret;
> > void *ffs_dev;
> > struct ffs_data *ffs;
> >
> > ENTER();
> >
> >
> > ret = ffs_fs_parse_opts(&data, opts);
> > if (unlikely(ret < 0))
> > return ERR_PTR(ret);
> >
> > ffs = ffs_data_new();
> > if (unlikely(!ffs))
> > return ERR_PTR(-ENOMEM);
> > ffs->file_perms = data.perms;
> >
> > ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
> > if (unlikely(!ffs->dev_name)) {
> > ffs_data_put(ffs);
> > return ERR_PTR(-ENOMEM);
> > }
> >
> > ffs_dev = functionfs_acquire_dev_callback(dev_name);
> > if (IS_ERR(ffs_dev)) {
> > ffs_data_put(ffs);
> > return ERR_CAST(ffs_dev);
> > }
> >
> > ffs->private_data = ffs_dev;
> > data.ffs_data = ffs;
> >
> > rv = mount_nodev(t, flags, &data, ffs_sb_fill);
> > if (IS_ERR(rv) && data.ffs_data) {
> > functionfs_release_dev_callback(data.ffs_data);
> > ffs_data_put(data.ffs_data);
> > }
> > return rv;
> > }
> >
> > 3.14 kernel:
> > static struct dentry *
> > ffs_fs_mount(struct file_system_type *t, int flags,
> > const char *dev_name, void *opts)
> > {
> > struct ffs_sb_fill_data data = {
> > .perms = {
> > .mode = S_IFREG | 0600,
> > .uid = GLOBAL_ROOT_UID,
> > .gid = GLOBAL_ROOT_GID,
> > },
> > .root_mode = S_IFDIR | 0500,
> > };
> > struct dentry *rv;
> > int ret;
> > void *ffs_dev;
> > struct ffs_data *ffs;
> >
> > ENTER();
> >
> > ret = ffs_fs_parse_opts(&data, opts);
> > if (unlikely(ret < 0))
> > return ERR_PTR(ret);
> >
> > ffs = ffs_data_new();
> > if (unlikely(!ffs))
> > return ERR_PTR(-ENOMEM);
> > ffs->file_perms = data.perms;
> >
> > ffs->dev_name = kstrdup(dev_name, GFP_KERNEL);
> > if (unlikely(!ffs->dev_name)) {
> > ffs_data_put(ffs);
> > return ERR_PTR(-ENOMEM);
> > }
> >
> > ffs_dev = ffs_acquire_dev(dev_name);
> > if (IS_ERR(ffs_dev)) {
> > ffs_data_put(ffs);
> > return ERR_CAST(ffs_dev);
> > }
> > ffs->private_data = ffs_dev;
> > data.ffs_data = ffs;
> >
> > rv = mount_nodev(t, flags, &data, ffs_sb_fill);
> > if (IS_ERR(rv) && data.ffs_data) {
> > ffs_release_dev(data.ffs_data);
> > ffs_data_put(data.ffs_data);
> > }
> > return rv;
> > }
> >
> > --
> > --
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