USB: g_ffs: the FunctionFS gadget driver

The Function Filesystem (FunctioFS) lets one create USB
composite functions in user space in the same way as GadgetFS
lets one create USB gadgets in user space.  This allows
creation of composite gadgets such that some of the functions
are implemented in kernel space (for instance Ethernet, serial
or mass storage) and other are implemented in user space.
Signed-off-by: NMichal Nazarewicz <m.nazarewicz@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/Kconfig

@@ -710,6 +710,43 @@ config USB_GADGETFS
 	  Say "y" to link the driver statically, or "m" to build a
 	  dynamically linked module called "gadgetfs".
 
+config USB_FUNCTIONFS
+	tristate "Function Filesystem (EXPERIMENTAL)"
+	depends on EXPERIMENTAL
+	help
+	  The Function Filesystem (FunctioFS) lets one create USB
+	  composite functions in user space in the same way as GadgetFS
+	  lets one create USB gadgets in user space.  This allows creation
+	  of composite gadgets such that some of the functions are
+	  implemented in kernel space (for instance Ethernet, serial or
+	  mass storage) and other are implemented in user space.
+
+	  Say "y" to link the driver statically, or "m" to build
+	  a dynamically linked module called "g_ffs".
+
+config USB_FUNCTIONFS_ETH
+	bool "Include CDC ECM (Ethernet) function"
+	depends on USB_FUNCTIONFS
+	help
+	  Include an CDC ECM (Ethernet) funcion in the CDC ECM (Funcion)
+	  Filesystem.  If you also say "y" to the RNDIS query below the
+	  gadget will have two configurations.
+
+config USB_FUNCTIONFS_RNDIS
+	bool "Include RNDIS (Ethernet) function"
+	depends on USB_FUNCTIONFS
+	help
+	  Include an RNDIS (Ethernet) funcion in the Funcion Filesystem.
+	  If you also say "y" to the CDC ECM query above the gadget will
+	  have two configurations.
+
+config USB_FUNCTIONFS_GENERIC
+	bool "Include 'pure' configuration"
+	depends on USB_FUNCTIONFS && (USB_FUNCTIONFS_ETH || USB_FUNCTIONFS_RNDIS)
+	help
+	  Include a configuration with FunctionFS and no Ethernet
+	  configuration.
+
 config USB_FILE_STORAGE
 	tristate "File-backed Storage Gadget"
 	depends on BLOCK

drivers/usb/gadget/Makefile

@@ -51,6 +51,8 @@ obj-$(CONFIG_USB_ZERO)		+= g_zero.o
 obj-$(CONFIG_USB_AUDIO)		+= g_audio.o
 obj-$(CONFIG_USB_ETH)		+= g_ether.o
 obj-$(CONFIG_USB_GADGETFS)	+= gadgetfs.o
+obj-$(CONFIG_USB_FUNCTIONFS)	+= g_ffs.o
+obj-$(CONFIG_USB_ETH_FUNCTIONFS)	+= g_eth_ffs.o
 obj-$(CONFIG_USB_FILE_STORAGE)	+= g_file_storage.o
 obj-$(CONFIG_USB_MASS_STORAGE)	+= g_mass_storage.o
 obj-$(CONFIG_USB_G_SERIAL)	+= g_serial.o

drivers/usb/gadget/g_ffs.c

+#include <linux/module.h>
+#include <linux/utsname.h>
+
+
+/*
+ * kbuild is not very cooperative with respect to linking separately
+ * compiled library objects into one module.  So for now we won't use
+ * separate compilation ... ensuring init/exit sections work to shrink
+ * the runtime footprint, and giving us at least some parts of what
+ * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
+ */
+
+#include "composite.c"
+#include "usbstring.c"
+#include "config.c"
+#include "epautoconf.c"
+
+#if defined CONFIG_USB_FUNCTIONFS_ETH || defined CONFIG_USB_FUNCTIONFS_RNDIS
+#  if defined USB_ETH_RNDIS
+#    undef USB_ETH_RNDIS
+#  endif
+#  ifdef CONFIG_USB_FUNCTIONFS_RNDIS
+#    define USB_ETH_RNDIS y
+#  endif
+
+#  include "f_ecm.c"
+#  include "f_subset.c"
+#  ifdef USB_ETH_RNDIS
+#    include "f_rndis.c"
+#    include "rndis.c"
+#  endif
+#  include "u_ether.c"
+
+static u8 gfs_hostaddr[ETH_ALEN];
+#else
+#  if !defined CONFIG_USB_FUNCTIONFS_GENERIC
+#    define CONFIG_USB_FUNCTIONFS_GENERIC
+#  endif
+#  define gether_cleanup() do { } while (0)
+#  define gether_setup(gadget, hostaddr)   ((int)0)
+#endif
+
+#include "f_fs.c"
+
+
+#define DRIVER_NAME	"g_ffs"
+#define DRIVER_DESC	"USB Function Filesystem"
+#define DRIVER_VERSION	"24 Aug 2004"
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_AUTHOR("Michal Nazarewicz");
+MODULE_LICENSE("GPL");
+
+
+static unsigned short gfs_vendor_id    = 0x0525;	/* XXX NetChip */
+static unsigned short gfs_product_id   = 0xa4ac;	/* XXX */
+
+static struct usb_device_descriptor gfs_dev_desc = {
+	.bLength		= sizeof gfs_dev_desc,
+	.bDescriptorType	= USB_DT_DEVICE,
+
+	.bcdUSB			= cpu_to_le16(0x0200),
+	.bDeviceClass		= USB_CLASS_PER_INTERFACE,
+
+	/* Vendor and product id can be overridden by module parameters.  */
+	/* .idVendor		= cpu_to_le16(gfs_vendor_id), */
+	/* .idProduct		= cpu_to_le16(gfs_product_id), */
+	/* .bcdDevice		= f(hardware) */
+	/* .iManufacturer	= DYNAMIC */
+	/* .iProduct		= DYNAMIC */
+	/* NO SERIAL NUMBER */
+	.bNumConfigurations	= 1,
+};
+
+#define GFS_MODULE_PARAM_DESC(name, field) \
+	MODULE_PARM_DESC(name, "Value of the " #field " field of the device descriptor sent to the host.  Takes effect only prior to the user-space driver registering to the FunctionFS.")
+
+module_param_named(usb_class,    gfs_dev_desc.bDeviceClass,    byte,   0644);
+GFS_MODULE_PARAM_DESC(usb_class, bDeviceClass);
+module_param_named(usb_subclass, gfs_dev_desc.bDeviceSubClass, byte,   0644);
+GFS_MODULE_PARAM_DESC(usb_subclass, bDeviceSubClass);
+module_param_named(usb_protocol, gfs_dev_desc.bDeviceProtocol, byte,   0644);
+GFS_MODULE_PARAM_DESC(usb_protocol, bDeviceProtocol);
+module_param_named(usb_vendor,   gfs_vendor_id,                ushort, 0644);
+GFS_MODULE_PARAM_DESC(usb_vendor, idVendor);
+module_param_named(usb_product,  gfs_product_id,               ushort, 0644);
+GFS_MODULE_PARAM_DESC(usb_product, idProduct);
+
+
+
+static const struct usb_descriptor_header *gfs_otg_desc[] = {
+	(const struct usb_descriptor_header *)
+	&(const struct usb_otg_descriptor) {
+		.bLength		= sizeof(struct usb_otg_descriptor),
+		.bDescriptorType	= USB_DT_OTG,
+
+		/* REVISIT SRP-only hardware is possible, although
+		 * it would not be called "OTG" ... */
+		.bmAttributes		= USB_OTG_SRP | USB_OTG_HNP,
+	},
+
+	NULL
+};
+
+/* string IDs are assigned dynamically */
+
+enum {
+	GFS_STRING_MANUFACTURER_IDX,
+	GFS_STRING_PRODUCT_IDX,
+#ifdef CONFIG_USB_FUNCTIONFS_RNDIS
+	GFS_STRING_RNDIS_CONFIG_IDX,
+#endif
+#ifdef CONFIG_USB_FUNCTIONFS_ETH
+	GFS_STRING_ECM_CONFIG_IDX,
+#endif
+#ifdef CONFIG_USB_FUNCTIONFS_GENERIC
+	GFS_STRING_GENERIC_CONFIG_IDX,
+#endif
+};
+
+static       char gfs_manufacturer[50];
+static const char gfs_driver_desc[] = DRIVER_DESC;
+static const char gfs_short_name[]  = DRIVER_NAME;
+
+static struct usb_string gfs_strings[] = {
+	[GFS_STRING_MANUFACTURER_IDX].s = gfs_manufacturer,
+	[GFS_STRING_PRODUCT_IDX].s = gfs_driver_desc,
+#ifdef CONFIG_USB_FUNCTIONFS_RNDIS
+	[GFS_STRING_RNDIS_CONFIG_IDX].s = "FunctionFS + RNDIS",
+#endif
+#ifdef CONFIG_USB_FUNCTIONFS_ETH
+	[GFS_STRING_ECM_CONFIG_IDX].s = "FunctionFS + ECM",
+#endif
+#ifdef CONFIG_USB_FUNCTIONFS_GENERIC
+	[GFS_STRING_GENERIC_CONFIG_IDX].s = "FunctionFS",
+#endif
+	{  } /* end of list */
+};
+
+static struct usb_gadget_strings *gfs_dev_strings[] = {
+	&(struct usb_gadget_strings) {
+		.language	= 0x0409,	/* en-us */
+		.strings	= gfs_strings,
+	},
+	NULL,
+};
+
+
+#ifdef CONFIG_USB_FUNCTIONFS_RNDIS
+static int gfs_do_rndis_config(struct usb_configuration *c);
+
+static struct usb_configuration gfs_rndis_config_driver = {
+	.label			= "FunctionFS + RNDIS",
+	.bind			= gfs_do_rndis_config,
+	.bConfigurationValue	= 1,
+	/* .iConfiguration	= DYNAMIC */
+	.bmAttributes		= USB_CONFIG_ATT_SELFPOWER,
+};
+#  define gfs_add_rndis_config(cdev) \
+	usb_add_config(cdev, &gfs_rndis_config_driver)
+#else
+#  define gfs_add_rndis_config(cdev) 0
+#endif
+
+
+#ifdef CONFIG_USB_FUNCTIONFS_ETH
+static int gfs_do_ecm_config(struct usb_configuration *c);
+
+static struct usb_configuration gfs_ecm_config_driver = {
+	.label			= "FunctionFS + ECM",
+	.bind			= gfs_do_ecm_config,
+	.bConfigurationValue	= 1,
+	/* .iConfiguration	= DYNAMIC */
+	.bmAttributes		= USB_CONFIG_ATT_SELFPOWER,
+};
+#  define gfs_add_ecm_config(cdev) \
+	usb_add_config(cdev, &gfs_ecm_config_driver)
+#else
+#  define gfs_add_ecm_config(cdev) 0
+#endif
+
+
+#ifdef CONFIG_USB_FUNCTIONFS_GENERIC
+static int gfs_do_generic_config(struct usb_configuration *c);
+
+static struct usb_configuration gfs_generic_config_driver = {
+	.label			= "FunctionFS",
+	.bind			= gfs_do_generic_config,
+	.bConfigurationValue	= 2,
+	/* .iConfiguration	= DYNAMIC */
+	.bmAttributes		= USB_CONFIG_ATT_SELFPOWER,
+};
+#  define gfs_add_generic_config(cdev) \
+	usb_add_config(cdev, &gfs_generic_config_driver)
+#else
+#  define gfs_add_generic_config(cdev) 0
+#endif
+
+
+static int gfs_bind(struct usb_composite_dev *cdev);
+static int gfs_unbind(struct usb_composite_dev *cdev);
+
+static struct usb_composite_driver gfs_driver = {
+	.name		= gfs_short_name,
+	.dev		= &gfs_dev_desc,
+	.strings	= gfs_dev_strings,
+	.bind		= gfs_bind,
+	.unbind		= gfs_unbind,
+};
+
+
+static struct ffs_data *gfs_ffs_data;
+static unsigned long gfs_registered;
+
+
+static int  gfs_init(void)
+{
+	ENTER();
+
+	return functionfs_init();
+}
+module_init(gfs_init);
+
+static void  gfs_exit(void)
+{
+	ENTER();
+
+	if (test_and_clear_bit(0, &gfs_registered))
+		usb_composite_unregister(&gfs_driver);
+
+	functionfs_cleanup();
+}
+module_exit(gfs_exit);
+
+
+static int functionfs_ready_callback(struct ffs_data *ffs)
+{
+	int ret;
+
+	ENTER();
+
+	if (WARN_ON(test_and_set_bit(0, &gfs_registered)))
+		return -EBUSY;
+
+	gfs_ffs_data = ffs;
+	ret = usb_composite_register(&gfs_driver);
+	if (unlikely(ret < 0))
+		clear_bit(0, &gfs_registered);
+	return ret;
+}
+
+static void functionfs_closed_callback(struct ffs_data *ffs)
+{
+	ENTER();
+
+	if (test_and_clear_bit(0, &gfs_registered))
+		usb_composite_unregister(&gfs_driver);
+}
+
+
+static int functionfs_check_dev_callback(const char *dev_name)
+{
+	return 0;
+}
+
+
+
+static int gfs_bind(struct usb_composite_dev *cdev)
+{
+	int ret;
+
+	ENTER();
+
+	if (WARN_ON(!gfs_ffs_data))
+		return -ENODEV;
+
+	ret = gether_setup(cdev->gadget, gfs_hostaddr);
+	if (unlikely(ret < 0))
+		goto error_quick;
+
+	gfs_dev_desc.idVendor  = cpu_to_le16(gfs_vendor_id);
+	gfs_dev_desc.idProduct = cpu_to_le16(gfs_product_id);
+
+	snprintf(gfs_manufacturer, sizeof gfs_manufacturer, "%s %s with %s",
+		 init_utsname()->sysname, init_utsname()->release,
+		 cdev->gadget->name);
+	ret = usb_string_id(cdev);
+	if (unlikely(ret < 0))
+		goto error;
+	gfs_strings[GFS_STRING_MANUFACTURER_IDX].id = ret;
+	gfs_dev_desc.iManufacturer = ret;
+
+	ret = usb_string_id(cdev);
+	if (unlikely(ret < 0))
+		goto error;
+	gfs_strings[GFS_STRING_PRODUCT_IDX].id = ret;
+	gfs_dev_desc.iProduct = ret;
+
+#ifdef CONFIG_USB_FUNCTIONFS_RNDIS
+	ret = usb_string_id(cdev);
+	if (unlikely(ret < 0))
+		goto error;
+	gfs_strings[GFS_STRING_RNDIS_CONFIG_IDX].id = ret;
+	gfs_rndis_config_driver.iConfiguration = ret;
+#endif
+
+#ifdef CONFIG_USB_FUNCTIONFS_ETH
+	ret = usb_string_id(cdev);
+	if (unlikely(ret < 0))
+		goto error;
+	gfs_strings[GFS_STRING_ECM_CONFIG_IDX].id = ret;
+	gfs_ecm_config_driver.iConfiguration = ret;
+#endif
+
+#ifdef CONFIG_USB_FUNCTIONFS_GENERIC
+	ret = usb_string_id(cdev);
+	if (unlikely(ret < 0))
+		goto error;
+	gfs_strings[GFS_STRING_GENERIC_CONFIG_IDX].id = ret;
+	gfs_generic_config_driver.iConfiguration = ret;
+#endif
+
+	ret = functionfs_bind(gfs_ffs_data, cdev);
+	if (unlikely(ret < 0))
+		goto error;
+
+	ret = gfs_add_rndis_config(cdev);
+	if (unlikely(ret < 0))
+		goto error_unbind;
+
+	ret = gfs_add_ecm_config(cdev);
+	if (unlikely(ret < 0))
+		goto error_unbind;
+
+	ret = gfs_add_generic_config(cdev);
+	if (unlikely(ret < 0))
+		goto error_unbind;
+
+	return 0;
+
+error_unbind:
+	functionfs_unbind(gfs_ffs_data);
+error:
+	gether_cleanup();
+error_quick:
+	gfs_ffs_data = NULL;
+	return ret;
+}
+
+static int gfs_unbind(struct usb_composite_dev *cdev)
+{
+	ENTER();
+
+	/* We may have been called in an error recovery frem
+	 * composite_bind() after gfs_unbind() failure so we need to
+	 * check if gfs_ffs_data is not NULL since gfs_bind() handles
+	 * all error recovery itself.  I'd rather we werent called
+	 * from composite on orror recovery, but what you're gonna
+	 * do...? */
+
+	if (gfs_ffs_data) {
+		gether_cleanup();
+		functionfs_unbind(gfs_ffs_data);
+		gfs_ffs_data = NULL;
+	}
+
+	return 0;
+}
+
+
+static int __gfs_do_config(struct usb_configuration *c,
+			   int (*eth)(struct usb_configuration *c, u8 *ethaddr),
+			   u8 *ethaddr)
+{
+	int ret;
+
+	if (WARN_ON(!gfs_ffs_data))
+		return -ENODEV;
+
+	if (gadget_is_otg(c->cdev->gadget)) {
+		c->descriptors = gfs_otg_desc;
+		c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
+	}
+
+	if (eth) {
+		ret = eth(c, ethaddr);
+		if (unlikely(ret < 0))
+			return ret;
+	}
+
+	ret = functionfs_add(c->cdev, c, gfs_ffs_data);
+	if (unlikely(ret < 0))
+		return ret;
+
+	return 0;
+}
+
+#ifdef CONFIG_USB_FUNCTIONFS_RNDIS
+static int gfs_do_rndis_config(struct usb_configuration *c)
+{
+	ENTER();
+
+	return __gfs_do_config(c, rndis_bind_config, gfs_hostaddr);
+}
+#endif
+
+#ifdef CONFIG_USB_FUNCTIONFS_ETH
+static int gfs_do_ecm_config(struct usb_configuration *c)
+{
+	ENTER();
+
+	return __gfs_do_config(c,
+			       can_support_ecm(c->cdev->gadget)
+			     ? ecm_bind_config : geth_bind_config,
+			       gfs_hostaddr);
+}
+#endif
+
+#ifdef CONFIG_USB_FUNCTIONFS_GENERIC
+static int gfs_do_generic_config(struct usb_configuration *c)
+{
+	ENTER();
+
+	return __gfs_do_config(c, NULL, NULL);
+}
+#endif