/*
* f_eem.c -- USB CDC Ethernet (EEM) link function driver
*
* Copyright (C) 2003-2005,2008 David Brownell
* Copyright (C) 2008 Nokia Corporation
* Copyright (C) 2009 EF Johnson Technologies
*
* 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
*/
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/etherdevice.h>
#include <linux/crc32.h>
#include <linux/slab.h>
#include "u_ether.h"
#define EEM_HLEN 2
/*
* This function is a "CDC Ethernet Emulation Model" (CDC EEM)
* Ethernet link.
*/
struct eem_ep_descs {
struct usb_endpoint_descriptor *in;
struct usb_endpoint_descriptor *out;
};
struct f_eem {
struct gether port;
u8 ctrl_id;
struct eem_ep_descs fs;
struct eem_ep_descs hs;
};
static inline struct f_eem *func_to_eem(struct usb_function *f)
{
return container_of(f, struct f_eem, port.func);
}
/*-------------------------------------------------------------------------*/
/* interface descriptor: */
static struct usb_interface_descriptor eem_intf __initdata = {
.bLength = sizeof eem_intf,
.bDescriptorType = USB_DT_INTERFACE,
/* .bInterfaceNumber = DYNAMIC */
.bNumEndpoints = 2,
.bInterfaceClass = USB_CLASS_COMM,
.bInterfaceSubClass = USB_CDC_SUBCLASS_EEM,
.bInterfaceProtocol = USB_CDC_PROTO_EEM,
/* .iInterface = DYNAMIC */
};
/* full speed support: */
static struct usb_endpoint_descriptor eem_fs_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 eem_fs_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 *eem_fs_function[] __initdata = {
/* CDC EEM control descriptors */
(struct usb_descriptor_header *) &eem_intf,
(struct usb_descriptor_header *) &eem_fs_in_desc,
(struct usb_descriptor_header *) &eem_fs_out_desc,
NULL,
};
/* high speed support: */
static struct usb_endpoint_descriptor eem_hs_in_desc __initdata = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_IN,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(512),
};
static struct usb_endpoint_descriptor eem_hs_out_desc __initdata = {
.bLength = USB_DT_ENDPOINT_SIZE,
.bDescriptorType = USB_DT_ENDPOINT,
.bEndpointAddress = USB_DIR_OUT,
.bmAttributes = USB_ENDPOINT_XFER_BULK,
.wMaxPacketSize = cpu_to_le16(512),
};
static struct usb_descriptor_header *eem_hs_function[] __initdata = {
/* CDC EEM control descriptors */
(struct usb_descriptor_header *) &eem_intf,
(struct usb_descriptor_header *) &eem_hs_in_desc,
(struct usb_descriptor_header *) &eem_hs_out_desc,
NULL,
};
/* string descriptors: */
static struct usb_string eem_string_defs[] = {
[0].s = "CDC Ethernet Emulation Model (EEM)",
{ } /* end of list */
};
static struct usb_gadget_strings eem_string_table = {
.language = 0x0409, /* en-us */
.strings = eem_string_defs,
};
static struct usb_gadget_strings *eem_strings[] = {
&eem_string_table,
NULL,
};
/*-------------------------------------------------------------------------*/
static int eem_setup(struct usb_function *f, const struct usb_ctrlrequest *ctrl)
{
struct usb_composite_dev *cdev = f->config->cdev;
int value = -EOPNOTSUPP;
u16 w_index = le16_to_cpu(ctrl->wIndex);
u16 w_value = le16_to_cpu(ctrl->wValue);
u16 w_length = le16_to_cpu(ctrl->wLength);
DBG(cdev, "invalid control req%02x.%02x v%04x i%04x l%d\n",
ctrl->bRequestType, ctrl->bRequest,
w_value, w_index, w_length);
/* device either stalls (value < 0) or reports success */
return value;
}
static int eem_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
{
struct f_eem *eem = func_to_eem(f);
struct usb_composite_dev *cdev = f->config->cdev;
struct net_device *net;
/* we know alt == 0, so this is an activation or a reset */
if (alt != 0)
goto fail;
if (intf == eem->ctrl_id) {
if (eem->port.in_ep->driver_data) {
DBG(cdev, "reset eem\n");
gether_disconnect(&eem->port);
}
if (!eem->port.in) {
DBG(cdev, "init eem\n");
eem->port.in = ep_choose(cdev->gadget,
eem->hs.in, eem->fs.in);
eem->port.out = ep_choose(cdev->gadget,
eem->hs.out, eem->fs.out);
}
/* zlps should not occur because zero-length EEM packets
* will be inserted in those cases where they would occur
*/
eem->port.is_zlp_ok = 1;
eem->port.cdc_filter = DEFAULT_FILTER;
DBG(cdev, "activate eem\n");
net = gether_connect(&eem->port);
if (IS_ERR(net))
return PTR_ERR(net);
} else
goto fail;
return 0;
fail:
return -EINVAL;
}
static void eem_disable(struct usb_function *f)
{
struct f_eem *eem = func_to_eem(f);
struct usb_composite_dev *cdev = f->config->cdev;
DBG(cdev, "eem deactivated\n");
if (eem->port.in_ep->driver_data)
gether_disconnect(&eem->port);
}
/*-------------------------------------------------------------------------*/
/* EEM function driver setup/binding */
static int __init
eem_bind(struct usb_configuration *c, struct usb_function *f)
{
struct usb_composite_dev *cdev = c->cdev;
struct f_eem *eem = func_to_eem(f);
int status;
struct usb_ep *ep;
/* allocate instance-specific interface IDs */
status = usb_interface_id(c, f);
if (status < 0)
goto fail;
eem->ctrl_id = status;
eem_intf.bInterfaceNumber = status;
status = -ENODEV;
/* allocate instance-specific endpoints */
ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_in_desc);
if (!ep)
goto fail;
eem->port.in_ep = ep;
ep->driver_data = cdev; /* claim */
ep = usb_ep_autoconfig(cdev->gadget, &eem_fs_out_desc);
if (!ep)
goto fail;
eem->port.out_ep = ep;
ep->driver_data = cdev; /* claim */
status = -ENOMEM;
/* copy descriptors, and track endpoint copies */
f->descriptors = usb_copy_descriptors(eem_fs_function);
if (!f->descriptors)
goto fail;
eem->fs.in = usb_find_endpoint(eem_fs_function,
f->descriptors, &eem_fs_in_desc);
eem->fs.out = usb_find_endpoint(eem_fs_function,
f->descriptors, &eem_fs_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)) {
eem_hs_in_desc.bEndpointAddress =
eem_fs_in_desc.bEndpointAddress;
eem_hs_out_desc.bEndpointAddress =
eem_fs_out_desc.bEndpointAddress;
/* copy descriptors, and track endpoint copies */
f->hs_descriptors = usb_copy_descriptors(eem_hs_function);
if (!f->hs_descriptors)
goto fail;
eem->hs.in = usb_find_endpoint(eem_hs_function,
f->hs_descriptors, &eem_hs_in_desc);
eem->hs.out = usb_find_endpoint(eem_hs_function,
f->hs_descriptors, &eem_hs_out_desc);
}
DBG(cdev, "CDC Ethernet (EEM): %s speed IN/%s OUT/%s\n",
gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full",
eem->port.in_ep->name, eem->port.out_ep->name);
return 0;
fail:
if (f->descriptors)
usb_free_descriptors(f->descriptors);
/* we might as well release our claims on endpoints */
if (eem->port.out)
eem->port.out_ep->driver_data = NULL;
if (eem->port.in)
eem->port.in_ep->driver_data = NULL;
ERROR(cdev, "%s: can't bind, err %d\n", f->name, status);
return status;
}
static void
eem_unbind(struct usb_configuration *c, struct usb_function *f)
{
struct f_eem *eem = func_to_eem(f);
DBG(c->cdev, "eem unbind\n");
if (gadget_is_dualspeed(c->cdev->gadget))
usb_free_descriptors(f->hs_descriptors);
usb_free_descriptors(f->descriptors);
kfree(eem);
}
static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
{
struct sk_buff *skb = (struct sk_buff *)req->context;
dev_kfree_skb_any(skb);
}
/*
* Add the EEM header and ethernet checksum.
* We currently do not attempt to put multiple ethernet frames
* into a single USB transfer
*/
static struct sk_buff *eem_wrap(struct gether *port, struct sk_buff *skb)
{
struct sk_buff *skb2 = NULL;
struct usb_ep *in = port->in_ep;
int padlen = 0;
u16 len = skb->len;
if (!skb_cloned(skb)) {
int headroom = skb_headroom(skb);
int tailroom = skb_tailroom(skb);
/* When (len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) is 0,
* stick two bytes of zero-length EEM packet on the end.
*/
if (((len + EEM_HLEN + ETH_FCS_LEN) % in->maxpacket) == 0)
padlen += 2;
if ((tailroom >= (ETH_FCS_LEN + padlen)) &&
(headroom >= EEM_HLEN))
goto done;
}
skb2 = skb_copy_expand(skb, EEM_HLEN, ETH_FCS_LEN + padlen, GFP_ATOMIC);
dev_kfree_skb_any(skb);
skb = skb2;
if (!skb)
return skb;
done:
/* use the "no CRC" option */
put_unaligned_be32(0xdeadbeef, skb_put(skb, 4));
/* EEM packet header format:
* b0..13: length of ethernet frame
* b14: bmCRC (0 == sentinel CRC)
* b15: bmType (0 == data)
*/
len = skb->len;
put_unaligned_le16(len & 0x3FFF, skb_push(skb, 2));
/* add a zero-length EEM packet, if needed */
if (padlen)
put_unaligned_le16(0, skb_put(skb, 2));
return skb;
}
/*
* Remove the EEM header. Note that there can be many EEM packets in a single
* USB transfer, so we need to break them out and handle them independently.
*/
static int eem_unwrap(struct gether *port,
struct sk_buff *skb,
struct sk_buff_head *list)
{
struct usb_composite_dev *cdev = port->func.config->cdev;
int status = 0;
do {
struct sk_buff *skb2;
u16 header;
u16 len = 0;
if (skb->len < EEM_HLEN) {
status = -EINVAL;
DBG(cdev, "invalid EEM header\n");
goto error;
}
/* remove the EEM header */
header = get_unaligned_le16(skb->data);
skb_pull(skb, EEM_HLEN);
/* EEM packet header format:
* b0..14: EEM type dependent (data or command)
* b15: bmType (0 == data, 1 == command)
*/
if (header & BIT(15)) {
struct usb_request *req = cdev->req;
u16 bmEEMCmd;
/* EEM command packet format:
* b0..10: bmEEMCmdParam
* b11..13: bmEEMCmd
* b14: reserved (must be zero)
* b15: bmType (1 == command)
*/
if (header & BIT(14))
continue;
bmEEMCmd = (header >> 11) & 0x7;
switch (bmEEMCmd) {
case 0: /* echo */
len = header & 0x7FF;
if (skb->len < len) {
status = -EOVERFLOW;
goto error;
}
skb2 = skb_clone(skb, GFP_ATOMIC);
if (unlikely(!skb2)) {
DBG(cdev, "EEM echo response error\n");
goto next;
}
skb_trim(skb2, len);
put_unaligned_le16(BIT(15) | BIT(11) | len,
skb_push(skb2, 2));
skb_copy_bits(skb2, 0, req->buf, skb2->len);
req->length = skb2->len;
req->complete = eem_cmd_complete;
req->zero = 1;
req->context = skb2;
if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
DBG(cdev, "echo response queue fail\n");
break;
case 1: /* echo response */
case 2: /* suspend hint */
case 3: /* response hint */
case 4: /* response complete hint */
case 5: /* tickle */
default: /* reserved */
continue;
}
} else {
u32 crc, crc2;
struct sk_buff *skb3;
/* check for zero-length EEM packet */
if (header == 0)
continue;
/* EEM data packet format:
* b0..13: length of ethernet frame
* b14: bmCRC (0 == sentinel, 1 == calculated)
* b15: bmType (0 == data)
*/
len = header & 0x3FFF;
if ((skb->len < len)
|| (len < (ETH_HLEN + ETH_FCS_LEN))) {
status = -EINVAL;
goto error;
}
/* validate CRC */
if (header & BIT(14)) {
crc = get_unaligned_le32(skb->data + len
- ETH_FCS_LEN);
crc2 = ~crc32_le(~0,
skb->data, len - ETH_FCS_LEN);
} else {
crc = get_unaligned_be32(skb->data + len
- ETH_FCS_LEN);
crc2 = 0xdeadbeef;
}
if (crc != crc2) {
DBG(cdev, "invalid EEM CRC\n");
goto next;
}
skb2 = skb_clone(skb, GFP_ATOMIC);
if (unlikely(!skb2)) {
DBG(cdev, "unable to unframe EEM packet\n");
continue;
}
skb_trim(skb2, len - ETH_FCS_LEN);
skb3 = skb_copy_expand(skb2,
NET_IP_ALIGN,
0,
GFP_ATOMIC);
if (unlikely(!skb3)) {
DBG(cdev, "unable to realign EEM packet\n");
dev_kfree_skb_any(skb2);
continue;
}
dev_kfree_skb_any(skb2);
skb_queue_tail(list, skb3);
}
next:
skb_pull(skb, len);
} while (skb->len);
error:
dev_kfree_skb_any(skb);
return status;
}
/**
* eem_bind_config - add CDC Ethernet (EEM) network link to a configuration
* @c: the configuration to support the network link
* Context: single threaded during gadget setup
*
* Returns zero on success, else negative errno.
*
* Caller must have called @gether_setup(). Caller is also responsible
* for calling @gether_cleanup() before module unload.
*/
int __init eem_bind_config(struct usb_configuration *c)
{
struct f_eem *eem;
int status;
/* maybe allocate device-global string IDs */
if (eem_string_defs[0].id == 0) {
/* control interface label */
status = usb_string_id(c->cdev);
if (status < 0)
return status;
eem_string_defs[0].id = status;
eem_intf.iInterface = status;
}
/* allocate and initialize one new instance */
eem = kzalloc(sizeof *eem, GFP_KERNEL);
if (!eem)
return -ENOMEM;
eem->port.cdc_filter = DEFAULT_FILTER;
eem->port.func.name = "cdc_eem";
eem->port.func.strings = eem_strings;
/* descriptors are per-instance copies */
eem->port.func.bind = eem_bind;
eem->port.func.unbind = eem_unbind;
eem->port.func.set_alt = eem_set_alt;
eem->port.func.setup = eem_setup;
eem->port.func.disable = eem_disable;
eem->port.wrap = eem_wrap;
eem->port.unwrap = eem_unwrap;
eem->port.header_len = EEM_HLEN;
status = usb_add_function(c, &eem->port.func);
if (status)
kfree(eem);
return status;
}