FunctionFS: enable multiple functions
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Michal Nazarewicz <mina86@mina86.com> Cc: Felipe Balbi <balbi@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andrzej Pietrasiewicz
Greg Kroah-Hartman
Родитель
304f0b2453
Коммит
581791f5c7
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@ -0,0 +1,67 @@
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*How FunctionFS works*
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From kernel point of view it is just a composite function with some
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unique behaviour. It may be added to an USB configuration only after
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the user space driver has registered by writing descriptors and
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strings (the user space program has to provide the same information
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that kernel level composite functions provide when they are added to
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the configuration).
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This in particular means that the composite initialisation functions
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may not be in init section (ie. may not use the __init tag).
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From user space point of view it is a file system which when
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mounted provides an "ep0" file. User space driver need to
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write descriptors and strings to that file. It does not need
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to worry about endpoints, interfaces or strings numbers but
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simply provide descriptors such as if the function was the
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only one (endpoints and strings numbers starting from one and
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interface numbers starting from zero). The FunctionFS changes
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them as needed also handling situation when numbers differ in
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different configurations.
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When descriptors and strings are written "ep#" files appear
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(one for each declared endpoint) which handle communication on
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a single endpoint. Again, FunctionFS takes care of the real
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numbers and changing of the configuration (which means that
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"ep1" file may be really mapped to (say) endpoint 3 (and when
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configuration changes to (say) endpoint 2)). "ep0" is used
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for receiving events and handling setup requests.
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When all files are closed the function disables itself.
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What I also want to mention is that the FunctionFS is designed in such
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a way that it is possible to mount it several times so in the end
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a gadget could use several FunctionFS functions. The idea is that
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each FunctionFS instance is identified by the device name used
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when mounting.
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One can imagine a gadget that has an Ethernet, MTP and HID interfaces
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where the last two are implemented via FunctionFS. On user space
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level it would look like this:
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$ insmod g_ffs.ko idVendor=<ID> iSerialNumber=<string> functions=mtp,hid
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$ mkdir /dev/ffs-mtp && mount -t functionfs mtp /dev/ffs-mtp
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$ ( cd /dev/ffs-mtp && mtp-daemon ) &
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$ mkdir /dev/ffs-hid && mount -t functionfs hid /dev/ffs-hid
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$ ( cd /dev/ffs-hid && hid-daemon ) &
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On kernel level the gadget checks ffs_data->dev_name to identify
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whether it's FunctionFS designed for MTP ("mtp") or HID ("hid").
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If no "functions" module parameters is supplied, the driver accepts
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just one function with any name.
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When "functions" module parameter is supplied, only functions
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with listed names are accepted. In particular, if the "functions"
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parameter's value is just a one-element list, then the behaviour
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is similar to when there is no "functions" at all; however,
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only a function with the specified name is accepted.
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The gadget is registered only after all the declared function
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filesystems have been mounted and USB descriptors of all functions
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have been written to their ep0's.
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Conversely, the gadget is unregistered after the first USB function
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closes its endpoints.
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@ -1031,6 +1031,12 @@ struct ffs_sb_fill_data {
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struct ffs_file_perms perms;
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umode_t root_mode;
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const char *dev_name;
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union {
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/* set by ffs_fs_mount(), read by ffs_sb_fill() */
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void *private_data;
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/* set by ffs_sb_fill(), read by ffs_fs_mount */
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struct ffs_data *ffs_data;
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};
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};
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static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
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@ -1047,8 +1053,14 @@ static int ffs_sb_fill(struct super_block *sb, void *_data, int silent)
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goto Enomem;
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ffs->sb = sb;
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ffs->dev_name = data->dev_name;
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ffs->dev_name = kstrdup(data->dev_name, GFP_KERNEL);
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if (unlikely(!ffs->dev_name))
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goto Enomem;
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ffs->file_perms = data->perms;
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ffs->private_data = data->private_data;
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/* used by the caller of this function */
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data->ffs_data = ffs;
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sb->s_fs_info = ffs;
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sb->s_blocksize = PAGE_CACHE_SIZE;
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@ -1167,20 +1179,29 @@ ffs_fs_mount(struct file_system_type *t, int flags,
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},
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.root_mode = S_IFDIR | 0500,
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};
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struct dentry *rv;
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int ret;
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void *ffs_dev;
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ENTER();
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ret = functionfs_check_dev_callback(dev_name);
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if (unlikely(ret < 0))
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return ERR_PTR(ret);
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ret = ffs_fs_parse_opts(&data, opts);
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if (unlikely(ret < 0))
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return ERR_PTR(ret);
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ffs_dev = functionfs_acquire_dev_callback(dev_name);
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if (IS_ERR(ffs_dev))
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return ffs_dev;
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data.dev_name = dev_name;
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return mount_single(t, flags, &data, ffs_sb_fill);
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data.private_data = ffs_dev;
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rv = mount_nodev(t, flags, &data, ffs_sb_fill);
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/* data.ffs_data is set by ffs_sb_fill */
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if (IS_ERR(rv))
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functionfs_release_dev_callback(data.ffs_data);
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return rv;
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}
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static void
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@ -1189,8 +1210,10 @@ ffs_fs_kill_sb(struct super_block *sb)
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ENTER();
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kill_litter_super(sb);
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if (sb->s_fs_info)
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if (sb->s_fs_info) {
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functionfs_release_dev_callback(sb->s_fs_info);
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ffs_data_put(sb->s_fs_info);
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}
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}
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static struct file_system_type ffs_fs_type = {
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@ -1256,6 +1279,7 @@ static void ffs_data_put(struct ffs_data *ffs)
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ffs_data_clear(ffs);
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BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
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waitqueue_active(&ffs->ep0req_completion.wait));
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kfree(ffs->dev_name);
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kfree(ffs);
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}
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}
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@ -67,6 +67,15 @@ MODULE_LICENSE("GPL");
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#define GFS_VENDOR_ID 0x1d6b /* Linux Foundation */
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#define GFS_PRODUCT_ID 0x0105 /* FunctionFS Gadget */
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#define GFS_MAX_DEVS 10
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struct gfs_ffs_obj {
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const char *name;
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bool mounted;
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bool desc_ready;
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struct ffs_data *ffs_data;
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};
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static struct usb_device_descriptor gfs_dev_desc = {
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.bLength = sizeof gfs_dev_desc,
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.bDescriptorType = USB_DT_DEVICE,
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@ -78,12 +87,17 @@ static struct usb_device_descriptor gfs_dev_desc = {
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.idProduct = cpu_to_le16(GFS_PRODUCT_ID),
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};
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static char *func_names[GFS_MAX_DEVS];
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static unsigned int func_num;
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module_param_named(bDeviceClass, gfs_dev_desc.bDeviceClass, byte, 0644);
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MODULE_PARM_DESC(bDeviceClass, "USB Device class");
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module_param_named(bDeviceSubClass, gfs_dev_desc.bDeviceSubClass, byte, 0644);
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MODULE_PARM_DESC(bDeviceSubClass, "USB Device subclass");
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module_param_named(bDeviceProtocol, gfs_dev_desc.bDeviceProtocol, byte, 0644);
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MODULE_PARM_DESC(bDeviceProtocol, "USB Device protocol");
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module_param_array_named(functions, func_names, charp, &func_num, 0);
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MODULE_PARM_DESC(functions, "USB Functions list");
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static const struct usb_descriptor_header *gfs_otg_desc[] = {
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(const struct usb_descriptor_header *)
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@ -158,13 +172,34 @@ static struct usb_composite_driver gfs_driver = {
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.iProduct = DRIVER_DESC,
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};
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static struct ffs_data *gfs_ffs_data;
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static unsigned long gfs_registered;
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static DEFINE_MUTEX(gfs_lock);
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static unsigned int missing_funcs;
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static bool gfs_ether_setup;
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static bool gfs_registered;
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static bool gfs_single_func;
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static struct gfs_ffs_obj *ffs_tab;
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static int __init gfs_init(void)
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{
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int i;
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ENTER();
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if (!func_num) {
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gfs_single_func = true;
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func_num = 1;
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}
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ffs_tab = kcalloc(func_num, sizeof *ffs_tab, GFP_KERNEL);
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if (!ffs_tab)
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return -ENOMEM;
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if (!gfs_single_func)
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for (i = 0; i < func_num; i++)
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ffs_tab[i].name = func_names[i];
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missing_funcs = func_num;
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return functionfs_init();
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}
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module_init(gfs_init);
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@ -172,63 +207,165 @@ module_init(gfs_init);
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static void __exit gfs_exit(void)
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{
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ENTER();
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mutex_lock(&gfs_lock);
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if (test_and_clear_bit(0, &gfs_registered))
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if (gfs_registered)
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usb_composite_unregister(&gfs_driver);
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gfs_registered = false;
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functionfs_cleanup();
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mutex_unlock(&gfs_lock);
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kfree(ffs_tab);
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}
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module_exit(gfs_exit);
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static int functionfs_ready_callback(struct ffs_data *ffs)
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static struct gfs_ffs_obj *gfs_find_dev(const char *dev_name)
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{
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int ret;
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int i;
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ENTER();
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if (WARN_ON(test_and_set_bit(0, &gfs_registered)))
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return -EBUSY;
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if (gfs_single_func)
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return &ffs_tab[0];
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for (i = 0; i < func_num; i++)
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if (strcmp(ffs_tab[i].name, dev_name) == 0)
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return &ffs_tab[i];
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return NULL;
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}
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static int functionfs_ready_callback(struct ffs_data *ffs)
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{
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struct gfs_ffs_obj *ffs_obj;
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int ret;
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ENTER();
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mutex_lock(&gfs_lock);
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ffs_obj = ffs->private_data;
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if (!ffs_obj) {
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ret = -EINVAL;
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goto done;
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}
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if (WARN_ON(ffs_obj->desc_ready)) {
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ret = -EBUSY;
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goto done;
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}
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ffs_obj->desc_ready = true;
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ffs_obj->ffs_data = ffs;
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if (--missing_funcs) {
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ret = 0;
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goto done;
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}
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if (gfs_registered) {
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ret = -EBUSY;
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goto done;
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}
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gfs_registered = true;
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gfs_ffs_data = ffs;
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ret = usb_composite_probe(&gfs_driver, gfs_bind);
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if (unlikely(ret < 0))
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clear_bit(0, &gfs_registered);
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gfs_registered = false;
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done:
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mutex_unlock(&gfs_lock);
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return ret;
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}
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static void functionfs_closed_callback(struct ffs_data *ffs)
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{
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struct gfs_ffs_obj *ffs_obj;
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ENTER();
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mutex_lock(&gfs_lock);
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if (test_and_clear_bit(0, &gfs_registered))
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ffs_obj = ffs->private_data;
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if (!ffs_obj)
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goto done;
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ffs_obj->desc_ready = false;
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missing_funcs++;
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|
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if (gfs_registered)
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usb_composite_unregister(&gfs_driver);
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gfs_registered = false;
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done:
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mutex_unlock(&gfs_lock);
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}
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|
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static int functionfs_check_dev_callback(const char *dev_name)
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static void *functionfs_acquire_dev_callback(const char *dev_name)
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{
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return 0;
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struct gfs_ffs_obj *ffs_dev;
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|
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ENTER();
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mutex_lock(&gfs_lock);
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|
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ffs_dev = gfs_find_dev(dev_name);
|
||||
if (!ffs_dev) {
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ffs_dev = ERR_PTR(-ENODEV);
|
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goto done;
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||||
}
|
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|
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if (ffs_dev->mounted) {
|
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ffs_dev = ERR_PTR(-EBUSY);
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goto done;
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}
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ffs_dev->mounted = true;
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|
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done:
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mutex_unlock(&gfs_lock);
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return ffs_dev;
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}
|
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|
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static void functionfs_release_dev_callback(struct ffs_data *ffs_data)
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{
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struct gfs_ffs_obj *ffs_dev;
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|
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ENTER();
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mutex_lock(&gfs_lock);
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|
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ffs_dev = ffs_data->private_data;
|
||||
if (ffs_dev)
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ffs_dev->mounted = false;
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|
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mutex_unlock(&gfs_lock);
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}
|
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|
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/*
|
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* It is assumed that gfs_bind is called from a context where gfs_lock is held
|
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*/
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static int gfs_bind(struct usb_composite_dev *cdev)
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{
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||||
int ret, i;
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||||
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ENTER();
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if (WARN_ON(!gfs_ffs_data))
|
||||
if (missing_funcs)
|
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return -ENODEV;
|
||||
|
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ret = gether_setup(cdev->gadget, gfs_hostaddr);
|
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if (unlikely(ret < 0))
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goto error_quick;
|
||||
gfs_ether_setup = true;
|
||||
|
||||
ret = usb_string_ids_tab(cdev, gfs_strings);
|
||||
if (unlikely(ret < 0))
|
||||
goto error;
|
||||
|
||||
ret = functionfs_bind(gfs_ffs_data, cdev);
|
||||
if (unlikely(ret < 0))
|
||||
goto error;
|
||||
for (i = func_num; --i; ) {
|
||||
ret = functionfs_bind(ffs_tab[i].ffs_data, cdev);
|
||||
if (unlikely(ret < 0)) {
|
||||
while (++i < func_num)
|
||||
functionfs_unbind(ffs_tab[i].ffs_data);
|
||||
goto error;
|
||||
}
|
||||
}
|
||||
|
||||
for (i = 0; i < ARRAY_SIZE(gfs_configurations); ++i) {
|
||||
struct gfs_configuration *c = gfs_configurations + i;
|
||||
|
|
@ -246,16 +383,22 @@ static int gfs_bind(struct usb_composite_dev *cdev)
|
|||
return 0;
|
||||
|
||||
error_unbind:
|
||||
functionfs_unbind(gfs_ffs_data);
|
||||
for (i = 0; i < func_num; i++)
|
||||
functionfs_unbind(ffs_tab[i].ffs_data);
|
||||
error:
|
||||
gether_cleanup();
|
||||
error_quick:
|
||||
gfs_ffs_data = NULL;
|
||||
gfs_ether_setup = false;
|
||||
return ret;
|
||||
}
|
||||
|
||||
/*
|
||||
* It is assumed that gfs_unbind is called from a context where gfs_lock is held
|
||||
*/
|
||||
static int gfs_unbind(struct usb_composite_dev *cdev)
|
||||
{
|
||||
int i;
|
||||
|
||||
ENTER();
|
||||
|
||||
/*
|
||||
|
|
@ -266,22 +409,29 @@ static int gfs_unbind(struct usb_composite_dev *cdev)
|
|||
* from composite on orror recovery, but what you're gonna
|
||||
* do...?
|
||||
*/
|
||||
if (gfs_ffs_data) {
|
||||
if (gfs_ether_setup)
|
||||
gether_cleanup();
|
||||
functionfs_unbind(gfs_ffs_data);
|
||||
gfs_ffs_data = NULL;
|
||||
}
|
||||
gfs_ether_setup = false;
|
||||
|
||||
for (i = func_num; --i; )
|
||||
if (ffs_tab[i].ffs_data)
|
||||
functionfs_unbind(ffs_tab[i].ffs_data);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* It is assumed that gfs_do_config is called from a context where
|
||||
* gfs_lock is held
|
||||
*/
|
||||
static int gfs_do_config(struct usb_configuration *c)
|
||||
{
|
||||
struct gfs_configuration *gc =
|
||||
container_of(c, struct gfs_configuration, c);
|
||||
int i;
|
||||
int ret;
|
||||
|
||||
if (WARN_ON(!gfs_ffs_data))
|
||||
if (missing_funcs)
|
||||
return -ENODEV;
|
||||
|
||||
if (gadget_is_otg(c->cdev->gadget)) {
|
||||
|
|
@ -295,9 +445,11 @@ static int gfs_do_config(struct usb_configuration *c)
|
|||
return ret;
|
||||
}
|
||||
|
||||
ret = functionfs_bind_config(c->cdev, c, gfs_ffs_data);
|
||||
if (unlikely(ret < 0))
|
||||
return ret;
|
||||
for (i = 0; i < func_num; i++) {
|
||||
ret = functionfs_bind_config(c->cdev, c, ffs_tab[i].ffs_data);
|
||||
if (unlikely(ret < 0))
|
||||
return ret;
|
||||
}
|
||||
|
||||
/*
|
||||
* After previous do_configs there may be some invalid
|
||||
|
|
|
|||
|
|
@ -190,8 +190,10 @@ static int functionfs_ready_callback(struct ffs_data *ffs)
|
|||
__attribute__((warn_unused_result, nonnull));
|
||||
static void functionfs_closed_callback(struct ffs_data *ffs)
|
||||
__attribute__((nonnull));
|
||||
static int functionfs_check_dev_callback(const char *dev_name)
|
||||
static void *functionfs_acquire_dev_callback(const char *dev_name)
|
||||
__attribute__((warn_unused_result, nonnull));
|
||||
static void functionfs_release_dev_callback(struct ffs_data *ffs_data)
|
||||
__attribute__((nonnull));
|
||||
|
||||
|
||||
#endif
|
||||
|
|
|
|||
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