usb gadget: cdc obex glue

The following patch introduces a new f_obex.c function driver.
It allows userspace obex servers to use usb as transport layer
for their messages.

[ dbrownell@users.sourceforge.net: various fixes and cleanups ]

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 446 insertions, 0 deletions

diff --git a/drivers/usb/gadget/f_obex.c b/drivers/usb/gadget/f_obex.c
new file mode 100644
index 000000000000..86241b2ca8f4
--- /dev/null
+++ b/drivers/usb/gadget/f_obex.c
@@ -0,0 +1,446 @@
+/*
+ * f_obex.c -- USB CDC OBEX function driver
+ *
+ * Copyright (C) 2008 Nokia Corporation
+ * Contact: Felipe Balbi <felipe.balbi@nokia.com>
+ *
+ * Based on f_acm.c by Al Borchers and David Brownell.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+/* #define VERBOSE_DEBUG */
+
+#include <linux/kernel.h>
+#include <linux/utsname.h>
+#include <linux/device.h>
+
+#include "u_serial.h"
+#include "gadget_chips.h"
+
+
+/*
+ * This CDC OBEX function support just packages a TTY-ish byte stream.
+ * A user mode server will put it into "raw" mode and handle all the
+ * relevant protocol details ... this is just a kernel passthrough.
+ *
+ * REVISIT this driver shouldn't actually activate before that user mode
+ * server is ready to respond!  When the "serial gadget" utility code
+ * adds open/close notifications, this driver should use them with new
+ * (TBS) composite gadget hooks that wrap usb_gadget_disconnect() and
+ * usb_gadget_connect() calls with refcounts ... disconnect() when we
+ * bind, then connect() when the user server code is ready to respond.
+ */
+
+struct obex_ep_descs {
+        struct usb_endpoint_descriptor  *obex_in;
+        struct usb_endpoint_descriptor  *obex_out;
+};
+
+struct f_obex {
+        struct gserial                  port;
+        u8                              ctrl_id;
+        u8                              data_id;
+        u8                              port_num;
+
+        struct obex_ep_descs            fs;
+        struct obex_ep_descs            hs;
+};
+
+static inline struct f_obex *func_to_obex(struct usb_function *f)
+{
+        return container_of(f, struct f_obex, port.func);
+}
+
+/*-------------------------------------------------------------------------*/
+
+#define OBEX_CTRL_IDX   0
+#define OBEX_DATA_IDX   1
+
+static struct usb_string obex_string_defs[] = {
+        [OBEX_CTRL_IDX].s       = "CDC Object Exchange (OBEX)",
+        [OBEX_DATA_IDX].s       = "CDC OBEX Data",
+        {  },   /* end of list */
+};
+
+static struct usb_gadget_strings obex_string_table = {
+        .language               = 0x0409,       /* en-US */
+        .strings                = obex_string_defs,
+};
+
+static struct usb_gadget_strings *obex_strings[] = {
+        &obex_string_table,
+        NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static struct usb_interface_descriptor obex_control_intf __initdata = {
+        .bLength                = sizeof(obex_control_intf),
+        .bDescriptorType        = USB_DT_INTERFACE,
+        .bInterfaceNumber       = 0,
+
+        .bAlternateSetting      = 0,
+        .bNumEndpoints          = 0,
+        .bInterfaceClass        = USB_CLASS_COMM,
+        .bInterfaceSubClass     = USB_CDC_SUBCLASS_OBEX,
+};
+
+static struct usb_interface_descriptor obex_data_nop_intf __initdata = {
+        .bLength                = sizeof(obex_data_nop_intf),
+        .bDescriptorType        = USB_DT_INTERFACE,
+        .bInterfaceNumber       = 1,
+
+        .bAlternateSetting      = 0,
+        .bNumEndpoints          = 0,
+        .bInterfaceClass        = USB_CLASS_CDC_DATA,
+};
+
+static struct usb_interface_descriptor obex_data_intf __initdata = {
+        .bLength                = sizeof(obex_data_intf),
+        .bDescriptorType        = USB_DT_INTERFACE,
+        .bInterfaceNumber       = 2,
+
+        .bAlternateSetting      = 1,
+        .bNumEndpoints          = 2,
+        .bInterfaceClass        = USB_CLASS_CDC_DATA,
+};
+
+static struct usb_cdc_header_desc obex_cdc_header_desc __initdata = {
+        .bLength                = sizeof(obex_cdc_header_desc),
+        .bDescriptorType        = USB_DT_CS_INTERFACE,
+        .bDescriptorSubType     = USB_CDC_HEADER_TYPE,
+        .bcdCDC                 = __constant_cpu_to_le16(0x0120),
+};
+
+static struct usb_cdc_union_desc obex_cdc_union_desc __initdata = {
+        .bLength                = sizeof(obex_cdc_union_desc),
+        .bDescriptorType        = USB_DT_CS_INTERFACE,
+        .bDescriptorSubType     = USB_CDC_UNION_TYPE,
+        .bMasterInterface0      = 1,
+        .bSlaveInterface0       = 2,
+};
+
+static struct usb_cdc_obex_desc obex_desc __initdata = {
+        .bLength                = sizeof(obex_desc),
+        .bDescriptorType        = USB_DT_CS_INTERFACE,
+        .bDescriptorSubType     = USB_CDC_OBEX_TYPE,
+        .bcdVersion             = __constant_cpu_to_le16(0x0100),
+};
+
+/* High-Speed Support */
+
+static struct usb_endpoint_descriptor obex_hs_ep_out_desc __initdata = {
+        .bLength                = USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType        = USB_DT_ENDPOINT,
+
+        .bEndpointAddress       = USB_DIR_OUT,
+        .bmAttributes           = USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize         = __constant_cpu_to_le16(512),
+};
+
+static struct usb_endpoint_descriptor obex_hs_ep_in_desc __initdata = {
+        .bLength                = USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType        = USB_DT_ENDPOINT,
+
+        .bEndpointAddress       = USB_DIR_IN,
+        .bmAttributes           = USB_ENDPOINT_XFER_BULK,
+        .wMaxPacketSize         = __constant_cpu_to_le16(512),
+};
+
+static struct usb_descriptor_header *hs_function[] __initdata = {
+        (struct usb_descriptor_header *) &obex_control_intf,
+        (struct usb_descriptor_header *) &obex_cdc_header_desc,
+        (struct usb_descriptor_header *) &obex_desc,
+        (struct usb_descriptor_header *) &obex_cdc_union_desc,
+
+        (struct usb_descriptor_header *) &obex_data_nop_intf,
+        (struct usb_descriptor_header *) &obex_data_intf,
+        (struct usb_descriptor_header *) &obex_hs_ep_in_desc,
+        (struct usb_descriptor_header *) &obex_hs_ep_out_desc,
+        NULL,
+};
+
+/* Full-Speed Support */
+
+static struct usb_endpoint_descriptor obex_fs_ep_in_desc __initdata = {
+        .bLength                = USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType        = USB_DT_ENDPOINT,
+
+        .bEndpointAddress       = USB_DIR_IN,
+        .bmAttributes           = USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_endpoint_descriptor obex_fs_ep_out_desc __initdata = {
+        .bLength                = USB_DT_ENDPOINT_SIZE,
+        .bDescriptorType        = USB_DT_ENDPOINT,
+
+        .bEndpointAddress       = USB_DIR_OUT,
+        .bmAttributes           = USB_ENDPOINT_XFER_BULK,
+};
+
+static struct usb_descriptor_header *fs_function[] __initdata = {
+        (struct usb_descriptor_header *) &obex_control_intf,
+        (struct usb_descriptor_header *) &obex_cdc_header_desc,
+        (struct usb_descriptor_header *) &obex_desc,
+        (struct usb_descriptor_header *) &obex_cdc_union_desc,
+
+        (struct usb_descriptor_header *) &obex_data_nop_intf,
+        (struct usb_descriptor_header *) &obex_data_intf,
+        (struct usb_descriptor_header *) &obex_fs_ep_in_desc,
+        (struct usb_descriptor_header *) &obex_fs_ep_out_desc,
+        NULL,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static int obex_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
+{
+        struct f_obex           *obex = func_to_obex(f);
+        struct usb_composite_dev *cdev = f->config->cdev;
+
+        if (intf == obex->ctrl_id) {
+                if (alt != 0)
+                        goto fail;
+                /* NOP */
+                DBG(cdev, "reset obex ttyGS%d control\n", obex->port_num);
+
+        } else if (intf == obex->data_id) {
+                if (alt > 1)
+                        goto fail;
+
+                if (obex->port.in->driver_data) {
+                        DBG(cdev, "reset obex ttyGS%d\n", obex->port_num);
+                        gserial_disconnect(&obex->port);
+                }
+
+                if (!obex->port.in_desc) {
+                        DBG(cdev, "init obex ttyGS%d\n", obex->port_num);
+                        obex->port.in_desc = ep_choose(cdev->gadget,
+                                        obex->hs.obex_in, obex->fs.obex_in);
+                        obex->port.out_desc = ep_choose(cdev->gadget,
+                                        obex->hs.obex_out, obex->fs.obex_out);
+                }
+
+                if (alt == 1) {
+                        DBG(cdev, "activate obex ttyGS%d\n", obex->port_num);
+                        gserial_connect(&obex->port, obex->port_num);
+                }
+
+        } else
+                goto fail;
+
+        return 0;
+
+fail:
+        return -EINVAL;
+}
+
+static int obex_get_alt(struct usb_function *f, unsigned intf)
+{
+        struct f_obex           *obex = func_to_obex(f);
+
+        if (intf == obex->ctrl_id)
+                return 0;
+
+        return obex->port.in->driver_data ? 1 : 0;
+}
+
+static void obex_disable(struct usb_function *f)
+{
+        struct f_obex   *obex = func_to_obex(f);
+        struct usb_composite_dev *cdev = f->config->cdev;
+
+        DBG(cdev, "obex ttyGS%d disable\n", obex->port_num);
+        gserial_disconnect(&obex->port);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int __init
+obex_bind(struct usb_configuration *c, struct usb_function *f)
+{
+        struct usb_composite_dev *cdev = c->cdev;
+        struct f_obex           *obex = func_to_obex(f);
+        int                     status;
+        struct usb_ep           *ep;
+
+        /* allocate instance-specific interface IDs, and patch descriptors */
+
+        status = usb_interface_id(c, f);
+        if (status < 0)
+                goto fail;
+        obex->ctrl_id = status;
+
+        obex_control_intf.bInterfaceNumber = status;
+        obex_cdc_union_desc.bMasterInterface0 = status;
+
+        status = usb_interface_id(c, f);
+        if (status < 0)
+                goto fail;
+        obex->data_id = status;
+
+        obex_data_nop_intf.bInterfaceNumber = status;
+        obex_data_intf.bInterfaceNumber = status;
+        obex_cdc_union_desc.bSlaveInterface0 = status;
+
+        /* allocate instance-specific endpoints */
+
+        ep = usb_ep_autoconfig(cdev->gadget, &obex_fs_ep_in_desc);
+        if (!ep)
+                goto fail;
+        obex->port.in = ep;
+        ep->driver_data = cdev; /* claim */
+
+        ep = usb_ep_autoconfig(cdev->gadget, &obex_fs_ep_out_desc);
+        if (!ep)
+                goto fail;
+        obex->port.out = ep;
+        ep->driver_data = cdev; /* claim */
+
+        /* copy descriptors, and track endpoint copies */
+        f->descriptors = usb_copy_descriptors(fs_function);
+
+        obex->fs.obex_in = usb_find_endpoint(fs_function,
+                        f->descriptors, &obex_fs_ep_in_desc);
+        obex->fs.obex_out = usb_find_endpoint(fs_function,
+                        f->descriptors, &obex_fs_ep_out_desc);
+
+        /* support all relevant hardware speeds... we expect that when
+         * hardware is dual speed, all bulk-capable endpoints work at
+         * both speeds
+         */
+        if (gadget_is_dualspeed(c->cdev->gadget)) {
+
+                obex_hs_ep_in_desc.bEndpointAddress =
+                                obex_fs_ep_in_desc.bEndpointAddress;
+                obex_hs_ep_out_desc.bEndpointAddress =
+                                obex_fs_ep_out_desc.bEndpointAddress;
+
+                /* copy descriptors, and track endpoint copies */
+                f->hs_descriptors = usb_copy_descriptors(hs_function);
+
+                obex->hs.obex_in = usb_find_endpoint(hs_function,
+                                f->descriptors, &obex_hs_ep_in_desc);
+                obex->hs.obex_out = usb_find_endpoint(hs_function,
+                                f->descriptors, &obex_hs_ep_out_desc);
+        }
+
+        DBG(cdev, "obex ttyGS%d: %s speed IN/%s OUT/%s\n",
+                        obex->port_num,
+                        gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
+                        obex->port.in->name, obex->port.out->name);
+
+        return 0;
+
+fail:
+        /* we might as well release our claims on endpoints */
+        if (obex->port.out)
+                obex->port.out->driver_data = NULL;
+        if (obex->port.in)
+                obex->port.in->driver_data = NULL;
+
+        ERROR(cdev, "%s/%p: can't bind, err %d\n", f->name, f, status);
+
+        return status;
+}
+
+static void
+obex_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+        if (gadget_is_dualspeed(c->cdev->gadget))
+                usb_free_descriptors(f->hs_descriptors);
+        usb_free_descriptors(f->descriptors);
+        kfree(func_to_obex(f));
+}
+
+/* Some controllers can't support CDC OBEX ... */
+static inline bool can_support_obex(struct usb_configuration *c)
+{
+        /* Since the first interface is a NOP, we can ignore the
+         * issue of multi-interface support on most controllers.
+         *
+         * Altsettings are mandatory, however...
+         */
+        if (!gadget_supports_altsettings(c->cdev->gadget))
+                return false;
+
+        /* everything else is *probably* fine ... */
+        return true;
+}
+
+/**
+ * obex_bind_config - add a CDC OBEX function to a configuration
+ * @c: the configuration to support the CDC OBEX instance
+ * @port_num: /dev/ttyGS* port this interface will use
+ * Context: single threaded during gadget setup
+ *
+ * Returns zero on success, else negative errno.
+ *
+ * Caller must have called @gserial_setup() with enough ports to
+ * handle all the ones it binds.  Caller is also responsible
+ * for calling @gserial_cleanup() before module unload.
+ */
+int __init obex_bind_config(struct usb_configuration *c, u8 port_num)
+{
+        struct f_obex   *obex;
+        int             status;
+
+        if (!can_support_obex(c))
+                return -EINVAL;
+
+        /* maybe allocate device-global string IDs, and patch descriptors */
+        if (obex_string_defs[OBEX_CTRL_IDX].id == 0) {
+                status = usb_string_id(c->cdev);
+                if (status < 0)
+                        return status;
+                obex_string_defs[OBEX_CTRL_IDX].id = status;
+
+                obex_control_intf.iInterface = status;
+
+                status = usb_string_id(c->cdev);
+                if (status < 0)
+                        return status;
+                obex_string_defs[OBEX_DATA_IDX].id = status;
+
+                obex_data_nop_intf.iInterface =
+                        obex_data_intf.iInterface = status;
+        }
+
+        /* allocate and initialize one new instance */
+        obex = kzalloc(sizeof *obex, GFP_KERNEL);
+        if (!obex)
+                return -ENOMEM;
+
+        obex->port_num = port_num;
+
+        obex->port.func.name = "obex";
+        obex->port.func.strings = obex_strings;
+        /* descriptors are per-instance copies */
+        obex->port.func.bind = obex_bind;
+        obex->port.func.unbind = obex_unbind;
+        obex->port.func.set_alt = obex_set_alt;
+        obex->port.func.get_alt = obex_get_alt;
+        obex->port.func.disable = obex_disable;
+
+        status = usb_add_function(c, &obex->port.func);
+        if (status)
+                kfree(obex);
+
+        return status;
+}
+
+MODULE_AUTHOR("Felipe Balbi");
+MODULE_LICENSE("GPL");