I have been looking at the various options for USB/Ethernet
communication with an embedded target. I determined that CDC EEM met my
needs best, and since there was no CDC EEM gadget, I decided to try and
write one myself. I am fairly new to the USB code, so I thought I'd
submit it to the experts on this list for advice/review, and in case
this code is helpful to others. Any input would be appreciated. (Patch
is below)
Some things to note:
1. I changed the semantics of the wrap/unwrap callbacks in struct
gether as follows. This change necessitated a modification of the rndis
gadget.
wrap():
old semantics: Always copies the sk_buff. Caller is
responsible
for freeing original sk_buff.
new semantics: Only copies if necessary. For EEM it will often
not
be necessary since the 2-byte EEM header should fit within
the
reserved space. wrap() is responsible for freeing the
original
sk_buff, if necessary.
unwrap():
old semantics: sk_buff that comes out is the same is the one
that
went in, only with extra protocol trimmed off.
new semantics: An sk_buff list is returned since one USB request
could have multiple ethernet frames. The sk_buff that was
passed in is consumed by unwrap() (or placed on the queue).
2. I didn't know how to deal with the alignment problems generated by
the fact that there could be multiple ethernet frames in one USB
transfer. My solution was to (for each frame in the transfer): 1) clone
the original sk_buff, 2) trim the the clone down to a single frame, then
3) copy the trimmed sk_buff and place the copy on the unwrap queue.
This seems really expensive.
One potential solution would be to optimize for the general case, which
is a single ethernet frame at the beginning of the USB transfer. That
would require removing the NET_IP_ALIGN from the rx sk_buff (since the
EEM header is two bytes), then processing the first ethernet frame in
the transfer with just an skb_clone, and only copy the skb for any
additional frames. I did not implement this optimization because it
makes the code messier, but it may be worth it.
3. The wrap/unwrap callbacks now use port_usb from struct eth_dev, so
the appropriate spinlock is held with irqs disabled for the duration of
the wrap() or unwrap() callback. I'm thinking that might not be the
best idea.
4. I used the preallocated struct usb_request in struct
usb_composite_dev to send responses to EEM commands (currently only echo
response). I didn't do any sort of locking and/or state management
because the other drivers don't seem to, but it seems wrong because I
think there could be an outstanding command when another command comes
in. I think to be correct I'd have to keep track of whether or not a
command response is already in flight.
---
drivers/usb/gadget/Kconfig | 26 ++-
drivers/usb/gadget/ether.c | 31 ++-
drivers/usb/gadget/f_eem.c | 557
++++++++++++++++++++++++++++++++++++++++++
drivers/usb/gadget/rndis.c | 13 +-
drivers/usb/gadget/u_ether.c | 85 +++++--
drivers/usb/gadget/u_ether.h | 8 +-
6 files changed, 681 insertions(+), 39 deletions(-)
create mode 100644 drivers/usb/gadget/f_eem.c
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 26cfd0c..8d36bca 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -610,8 +610,8 @@ config USB_ETH
tristate "Ethernet Gadget (with CDC Ethernet support)"
depends on NET
help
- This driver implements Ethernet style communication, in either
- of two ways:
+ This driver implements Ethernet style communication, in one of
+ several ways:
- The "Communication Device Class" (CDC) Ethernet Control
Model.
That protocol is often avoided with pure Ethernet adapters,
in
@@ -621,7 +621,11 @@ config USB_ETH
- On hardware can't implement that protocol, a simple CDC
subset
is used, placing fewer demands on USB.
- RNDIS support is a third option, more demanding than that
subset.
+ - CDC Ethernet Emulation Model (EEM) is a newer standard that
has
+ a simpler interface that can be used by more USB hardware.
+
+ RNDIS support is an additional option, more demanding than
than
+ subset.
Within the USB device, this gadget driver exposes a network
device
"usbX", where X depends on what other networking devices you
have.
@@ -654,6 +658,22 @@ config USB_ETH_RNDIS
XP, you'll need to download drivers from Microsoft's website;
a URL
is given in comments found in that info file.
+config USB_ETH_EEM
+ bool "Ethernet Emulation Model (EEM) support"
+ depends on USB_ETH
+ default n
+ help
+ CDC EEM is a newer USB standard that is somewhat simpler than
CDC ECM
+ and therefore can be supported by more hardware. Technically
ECM and
+ EEM are designed for different applications. The ECM model
extends
+ the network interface to the target (e.g. a USB cable modem),
and the
+ EEM model is for mobile devices to communicate with hosts
using
+ ethernet over USB. For Linux gadgets, however, the interface
with
+ the host is the same (a usbX device), so the differences are
minimal.
+
+ If you say "y" here, the Ethernet gadget driver will use the
EEM
+ protocol rather than ECM. If unsure, say "n".
+
config USB_GADGETFS
tristate "Gadget Filesystem (EXPERIMENTAL)"
depends on EXPERIMENTAL
diff --git a/drivers/usb/gadget/ether.c b/drivers/usb/gadget/ether.c
index bd102f5..f37de28 100644
--- a/drivers/usb/gadget/ether.c
+++ b/drivers/usb/gadget/ether.c
@@ -61,6 +61,11 @@
* simpler, Microsoft pushes their own approach: RNDIS. The published
* RNDIS specs are ambiguous and appear to be incomplete, and are also
* needlessly complex. They borrow more from CDC ACM than CDC ECM.
+ *
+ * While CDC ECM, CDC Subset, and RNDIS are designed to extend the
ethernet
+ * interface to the target, CDC EEM was designed to use ethernet over
the USB
+ * link between the host and target. CDC EEM is implemented as an
alternative
+ * to those other protocols when that communication model is more
appropriate
*/
#define DRIVER_DESC "Ethernet Gadget"
@@ -114,6 +119,7 @@ static inline bool has_rndis(void)
#include "f_rndis.c"
#include "rndis.c"
#endif
+#include "f_eem.c"
#include "u_ether.c"
/*----------------------------------------------------------------------
---*/
@@ -150,6 +156,10 @@ static inline bool has_rndis(void)
#define RNDIS_VENDOR_NUM 0x0525 /* NetChip */
#define RNDIS_PRODUCT_NUM 0xa4a2 /* Ethernet/RNDIS Gadget */
+/* For EEM gadgets */
+#define EEM_VENDOR_NUM 0x0525 /* INVALID - NEEDS TO BE ALLOCATED */
+#define EEM_PRODUCT_NUM 0xa4a1 /* INVALID - NEEDS TO BE
ALLOCATED */
+
/*----------------------------------------------------------------------
---*/
static struct usb_device_descriptor device_desc = {
@@ -246,8 +256,16 @@ static struct usb_configuration rndis_config_driver
= {
/*----------------------------------------------------------------------
---*/
+#ifdef CONFIG_USB_ETH_EEM
+static int use_eem = 1;
+#else
+static int use_eem;
+#endif
+module_param(use_eem, bool, 0);
+MODULE_PARM_DESC(use_eem, "use CDC EEM mode");
+
/*
- * We _always_ have an ECM or CDC Subset configuration.
+ * We _always_ have an ECM, CDC Subset, or EEM configuration.
*/
static int __init eth_do_config(struct usb_configuration *c)
{
@@ -258,7 +276,9 @@ static int __init eth_do_config(struct
usb_configuration *c)
c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
}
- if (can_support_ecm(c->cdev->gadget))
+ if (use_eem)
+ return eem_bind_config(c);
+ else if (can_support_ecm(c->cdev->gadget))
return ecm_bind_config(c, hostaddr);
else
return geth_bind_config(c, hostaddr);
@@ -286,7 +306,12 @@ static int __init eth_bind(struct usb_composite_dev
*cdev)
return status;
/* set up main config label and device descriptor */
- if (can_support_ecm(cdev->gadget)) {
+ if (use_eem) {
+ /* EEM */
+ eth_config_driver.label = "CDC Ethernet (EEM)";
+ device_desc.idVendor = cpu_to_le16(EEM_VENDOR_NUM);
+ device_desc.idProduct = cpu_to_le16(EEM_PRODUCT_NUM);
+ } else if (can_support_ecm(cdev->gadget)) {
/* ECM */
eth_config_driver.label = "CDC Ethernet (ECM)";
} else {
diff --git a/drivers/usb/gadget/f_eem.c b/drivers/usb/gadget/f_eem.c
new file mode 100644
index 0000000..7c599cf
--- /dev/null
+++ b/drivers/usb/gadget/f_eem.c
@@ -0,0 +1,557 @@
+/*
+ * 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 "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)
+{
+}
+
+/*
+ * 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:
+ /* do not use the "no CRC" option */
+ put_unaligned_le32(~crc32_le(~0, skb->data, skb->len),
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) | BIT(14), 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(skb, 0, req->buf,
skb->len);
+ req->length = skb->len;
+ req->complete = eem_cmd_complete;
+ req->zero = 1;
+ 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 */
+ crc = get_unaligned_le32(skb->data + len -
ETH_FCS_LEN);
+ if (header & BIT(14))
+ crc2 = ~crc32_le(~0,
+ skb->data,
+ skb->len - ETH_FCS_LEN);
+ else
+ 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;
+}
+
diff --git a/drivers/usb/gadget/rndis.c b/drivers/usb/gadget/rndis.c
index ca41b0b..a246dec 100644
--- a/drivers/usb/gadget/rndis.c
+++ b/drivers/usb/gadget/rndis.c
@@ -1022,22 +1022,29 @@ static rndis_resp_t *rndis_add_response (int
configNr, u32 length)
return r;
}
-int rndis_rm_hdr(struct sk_buff *skb)
+int rndis_rm_hdr(struct gether *,
+ struct sk_buff *skb,
+ struct sk_buff_head *list)
{
/* tmp points to a struct rndis_packet_msg_type */
__le32 *tmp = (void *) skb->data;
/* MessageType, MessageLength */
if (cpu_to_le32(REMOTE_NDIS_PACKET_MSG)
- != get_unaligned(tmp++))
+ != get_unaligned(tmp++)) {
+ dev_kfree_skb_any(skb);
return -EINVAL;
+ }
tmp++;
/* DataOffset, DataLength */
- if (!skb_pull(skb, get_unaligned_le32(tmp++) + 8))
+ if (!skb_pull(skb, get_unaligned_le32(tmp++) + 8)) {
+ dev_kfree_skb_any(skb);
return -EOVERFLOW;
+ }
skb_trim(skb, get_unaligned_le32(tmp++));
+ skb_queue_tail(list, skb);
return 0;
}
diff --git a/drivers/usb/gadget/u_ether.c b/drivers/usb/gadget/u_ether.c
index aac69b5..9714a53 100644
--- a/drivers/usb/gadget/u_ether.c
+++ b/drivers/usb/gadget/u_ether.c
@@ -37,8 +37,9 @@
* one (!) network link through the USB gadget stack, normally "usb0".
*
* The control and data models are handled by the function driver which
- * connects to this code; such as CDC Ethernet, "CDC Subset", or RNDIS.
- * That includes all descriptor and endpoint management.
+ * connects to this code; such as CDC Ethernet (ECM or EEM),
+ * "CDC Subset", or RNDIS. That includes all descriptor and endpoint
+ * management.
*
* Link level addressing is handled by this component using module
* parameters; if no such parameters are provided, random link level
@@ -68,9 +69,13 @@ struct eth_dev {
struct list_head tx_reqs, rx_reqs;
atomic_t tx_qlen;
+ struct sk_buff_head rx_frames;
+
unsigned header_len;
- struct sk_buff *(*wrap)(struct sk_buff *skb);
- int (*unwrap)(struct sk_buff *skb);
+ struct sk_buff *(*wrap)(struct gether *, struct sk_buff
*skb);
+ int (*unwrap)(struct gether *,
+ struct sk_buff *skb,
+ struct sk_buff_head
*list);
struct work_struct work;
@@ -269,7 +274,7 @@ enomem:
static void rx_complete(struct usb_ep *ep, struct usb_request *req)
{
- struct sk_buff *skb = req->context;
+ struct sk_buff *skb = req->context, *skb2;
struct eth_dev *dev = ep->driver_data;
int status = req->status;
@@ -278,26 +283,47 @@ static void rx_complete(struct usb_ep *ep, struct
usb_request *req)
/* normal completion */
case 0:
skb_put(skb, req->actual);
- if (dev->unwrap)
- status = dev->unwrap(skb);
- if (status < 0
- || ETH_HLEN > skb->len
- || skb->len > ETH_FRAME_LEN) {
- dev->net->stats.rx_errors++;
- dev->net->stats.rx_length_errors++;
- DBG(dev, "rx length %d\n", skb->len);
- break;
- }
- skb->protocol = eth_type_trans(skb, dev->net);
- dev->net->stats.rx_packets++;
- dev->net->stats.rx_bytes += skb->len;
+ if (dev->unwrap) {
+ unsigned long flags;
- /* no buffer copies needed, unless hardware can't
- * use skb buffers.
- */
- status = netif_rx(skb);
+ spin_lock_irqsave(&dev->lock, flags);
+ if (dev->port_usb) {
+ status = dev->unwrap(dev->port_usb,
+ skb,
+
&dev->rx_frames);
+ } else {
+ dev_kfree_skb_any(skb);
+ status = -ENOTCONN;
+ }
+ spin_unlock_irqrestore(&dev->lock, flags);
+ } else {
+ skb_queue_tail(&dev->rx_frames, skb);
+ }
skb = NULL;
+
+ skb2 = skb_dequeue(&dev->rx_frames);
+ while (skb2) {
+ if (status < 0
+ || ETH_HLEN > skb2->len
+ || skb2->len > ETH_FRAME_LEN) {
+ dev->net->stats.rx_errors++;
+ dev->net->stats.rx_length_errors++;
+ DBG(dev, "rx length %d\n", skb2->len);
+ dev_kfree_skb_any(skb2);
+ goto next_frame;
+ }
+ skb2->protocol = eth_type_trans(skb2, dev->net);
+ dev->net->stats.rx_packets++;
+ dev->net->stats.rx_bytes += skb2->len;
+
+ /* no buffer copies needed, unless hardware
can't
+ * use skb buffers.
+ */
+ status = netif_rx(skb2);
+next_frame:
+ skb2 = skb_dequeue(&dev->rx_frames);
+ }
break;
/* software-driven interface shutdown */
@@ -536,14 +562,15 @@ static int eth_start_xmit(struct sk_buff *skb,
struct net_device *net)
* or there's not enough space for extra headers we need
*/
if (dev->wrap) {
- struct sk_buff *skb_new;
+ unsigned long flags;
- skb_new = dev->wrap(skb);
- if (!skb_new)
+ spin_lock_irqsave(&dev->lock, flags);
+ if (dev->port_usb)
+ skb = dev->wrap(dev->port_usb, skb);
+ spin_unlock_irqrestore(&dev->lock, flags);
+ if (!skb)
goto drop;
- dev_kfree_skb_any(skb);
- skb = skb_new;
length = skb->len;
}
req->buf = skb->data;
@@ -577,9 +604,9 @@ static int eth_start_xmit(struct sk_buff *skb,
struct net_device *net)
}
if (retval) {
+ dev_kfree_skb_any(skb);
drop:
dev->net->stats.tx_dropped++;
- dev_kfree_skb_any(skb);
spin_lock_irqsave(&dev->req_lock, flags);
if (list_empty(&dev->tx_reqs))
netif_start_queue(net);
@@ -752,6 +779,8 @@ int __init gether_setup(struct usb_gadget *g, u8
ethaddr[ETH_ALEN])
INIT_LIST_HEAD(&dev->tx_reqs);
INIT_LIST_HEAD(&dev->rx_reqs);
+ skb_queue_head_init(&dev->rx_frames);
+
/* network device setup */
dev->net = net;
strcpy(net->name, "usb%d");
diff --git a/drivers/usb/gadget/u_ether.h b/drivers/usb/gadget/u_ether.h
index 0d1f7ae..efa3178 100644
--- a/drivers/usb/gadget/u_ether.h
+++ b/drivers/usb/gadget/u_ether.h
@@ -64,8 +64,11 @@ struct gether {
* we currently don't support multiple frames per SKB.
*/
u32 header_len;
- struct sk_buff *(*wrap)(struct sk_buff *skb);
- int (*unwrap)(struct sk_buff *skb);
+ struct sk_buff *(*wrap)(struct gether *,
+ struct sk_buff *skb);
+ int (*unwrap)(struct gether *,
+ struct sk_buff *skb,
+ struct sk_buff_head
*list);
/* called on network open/close */
void (*open)(struct gether *);
@@ -109,6 +112,7 @@ static inline bool can_support_ecm(struct usb_gadget
*gadget)
/* each configuration may bind one instance of an ethernet link */
int geth_bind_config(struct usb_configuration *c, u8
ethaddr[ETH_ALEN]);
int ecm_bind_config(struct usb_configuration *c, u8 ethaddr[ETH_ALEN]);
+int eem_bind_config(struct usb_configuration *c);
#ifdef CONFIG_USB_ETH_RNDIS
--
1.6.0.4
--
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