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authorOmar Laazimani <omar.oberthur@gmail.com>2009-05-04 12:01:43 -0700
committerDavid S. Miller <davem@davemloft.net>2009-05-04 12:01:43 -0700
commit9f722c0978b04acba209f8ca1896ad05814bc3a3 (patch)
tree9c596d23beda50080a21a5ed90be3e9f4a6a5d1e /drivers/net/usb
parent0c266898b42fe4e4e2f9edfc9d3474c10f93aa6a (diff)
usbnet: CDC EEM support (v5)
This introduces a CDC Ethernet Emulation Model (EEM) host side driver to support USB EEM devices. EEM is different from the Ethernet Control Model (ECM) currently supported by the "CDC Ethernet" driver. One key difference is that it doesn't require of USB interface alternate settings to manage interface state; some maldesigned hardware can't handle that part of USB. It also avoids a separate USB interface for control and status updates. [ dbrownell@users.sourceforge.net: fix skb leaks, add rx packet checks, improve fault handling, EEM conformance updates, cleanup ] Signed-off-by: Omar Laazimani <omar.oberthur@gmail.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/usb')
-rw-r--r--drivers/net/usb/Kconfig14
-rw-r--r--drivers/net/usb/Makefile1
-rw-r--r--drivers/net/usb/cdc_eem.c381
3 files changed, 396 insertions, 0 deletions
diff --git a/drivers/net/usb/Kconfig b/drivers/net/usb/Kconfig
index 8ee21030e9a..dfc6cf765fb 100644
--- a/drivers/net/usb/Kconfig
+++ b/drivers/net/usb/Kconfig
@@ -180,6 +180,20 @@ config USB_NET_CDCETHER
IEEE 802 "local assignment" bit is set in the address, a "usbX"
name is used instead.
+config USB_NET_CDC_EEM
+ tristate "CDC EEM support"
+ depends on USB_USBNET && EXPERIMENTAL
+ help
+ This option supports devices conforming to the Communication Device
+ Class (CDC) Ethernet Emulation Model, a specification that's easy to
+ implement in device firmware. The CDC EEM specifications are available
+ from <http://www.usb.org/>.
+
+ This driver creates an interface named "ethX", where X depends on
+ what other networking devices you have in use. However, if the
+ IEEE 802 "local assignment" bit is set in the address, a "usbX"
+ name is used instead.
+
config USB_NET_DM9601
tristate "Davicom DM9601 based USB 1.1 10/100 ethernet devices"
depends on USB_USBNET
diff --git a/drivers/net/usb/Makefile b/drivers/net/usb/Makefile
index 88a87eeb376..c8aef62cf2b 100644
--- a/drivers/net/usb/Makefile
+++ b/drivers/net/usb/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_USB_RTL8150) += rtl8150.o
obj-$(CONFIG_USB_HSO) += hso.o
obj-$(CONFIG_USB_NET_AX8817X) += asix.o
obj-$(CONFIG_USB_NET_CDCETHER) += cdc_ether.o
+obj-$(CONFIG_USB_NET_CDC_EEM) += cdc_eem.o
obj-$(CONFIG_USB_NET_DM9601) += dm9601.o
obj-$(CONFIG_USB_NET_SMSC95XX) += smsc95xx.o
obj-$(CONFIG_USB_NET_GL620A) += gl620a.o
diff --git a/drivers/net/usb/cdc_eem.c b/drivers/net/usb/cdc_eem.c
new file mode 100644
index 00000000000..80e01778dd3
--- /dev/null
+++ b/drivers/net/usb/cdc_eem.c
@@ -0,0 +1,381 @@
+/*
+ * USB CDC EEM network interface driver
+ * Copyright (C) 2009 Oberthur Technologies
+ * by Omar Laazimani, Olivier Condemine
+ *
+ * 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/module.h>
+#include <linux/init.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/ctype.h>
+#include <linux/ethtool.h>
+#include <linux/workqueue.h>
+#include <linux/mii.h>
+#include <linux/usb.h>
+#include <linux/crc32.h>
+#include <linux/usb/cdc.h>
+#include <linux/usb/usbnet.h>
+
+
+/*
+ * This driver is an implementation of the CDC "Ethernet Emulation
+ * Model" (EEM) specification, which encapsulates Ethernet frames
+ * for transport over USB using a simpler USB device model than the
+ * previous CDC "Ethernet Control Model" (ECM, or "CDC Ethernet").
+ *
+ * For details, see www.usb.org/developers/devclass_docs/CDC_EEM10.pdf
+ *
+ * This version has been tested with GIGAntIC WuaoW SIM Smart Card on 2.6.24,
+ * 2.6.27 and 2.6.30rc2 kernel.
+ * It has also been validated on Openmoko Om 2008.12 (based on 2.6.24 kernel).
+ * build on 23-April-2009
+ */
+
+#define EEM_HEAD 2 /* 2 byte header */
+
+/*-------------------------------------------------------------------------*/
+
+static void eem_linkcmd_complete(struct urb *urb)
+{
+ dev_kfree_skb(urb->context);
+ usb_free_urb(urb);
+}
+
+static void eem_linkcmd(struct usbnet *dev, struct sk_buff *skb)
+{
+ struct urb *urb;
+ int status;
+
+ urb = usb_alloc_urb(0, GFP_ATOMIC);
+ if (!urb)
+ goto fail;
+
+ usb_fill_bulk_urb(urb, dev->udev, dev->out,
+ skb->data, skb->len, eem_linkcmd_complete, skb);
+
+ status = usb_submit_urb(urb, GFP_ATOMIC);
+ if (status) {
+ usb_free_urb(urb);
+fail:
+ dev_kfree_skb(skb);
+ devwarn(dev, "link cmd failure\n");
+ return;
+ }
+}
+
+static int eem_bind(struct usbnet *dev, struct usb_interface *intf)
+{
+ int status = 0;
+
+ status = usbnet_get_endpoints(dev, intf);
+ if (status < 0) {
+ usb_set_intfdata(intf, NULL);
+ usb_driver_release_interface(driver_of(intf), intf);
+ return status;
+ }
+
+ /* no jumbogram (16K) support for now */
+
+ dev->net->hard_header_len += EEM_HEAD + ETH_FCS_LEN;
+
+ return 0;
+}
+
+/*
+ * EEM permits packing multiple Ethernet frames into USB transfers
+ * (a "bundle"), but for TX we don't try to do that.
+ */
+static struct sk_buff *eem_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
+ gfp_t flags)
+{
+ struct sk_buff *skb2 = NULL;
+ u16 len = skb->len;
+ u32 crc = 0;
+ int padlen = 0;
+
+ /* When ((len + EEM_HEAD + ETH_FCS_LEN) % dev->maxpacket) is
+ * zero, stick two bytes of zero length EEM packet on the end.
+ * Else the framework would add invalid single byte padding,
+ * since it can't know whether ZLPs will be handled right by
+ * all the relevant hardware and software.
+ */
+ if (!((len + EEM_HEAD + ETH_FCS_LEN) % dev->maxpacket))
+ padlen += 2;
+
+ if (!skb_cloned(skb)) {
+ int headroom = skb_headroom(skb);
+ int tailroom = skb_tailroom(skb);
+
+ if ((tailroom >= ETH_FCS_LEN + padlen)
+ && (headroom >= EEM_HEAD))
+ goto done;
+
+ if ((headroom + tailroom)
+ > (EEM_HEAD + ETH_FCS_LEN + padlen)) {
+ skb->data = memmove(skb->head +
+ EEM_HEAD,
+ skb->data,
+ skb->len);
+ skb_set_tail_pointer(skb, len);
+ goto done;
+ }
+ }
+
+ skb2 = skb_copy_expand(skb, EEM_HEAD, ETH_FCS_LEN + padlen, flags);
+ if (!skb2)
+ return NULL;
+
+ dev_kfree_skb_any(skb);
+ skb = skb2;
+
+done:
+ /* we don't use the "no Ethernet CRC" option */
+ crc = crc32_le(~0, skb->data, skb->len);
+ crc = ~crc;
+
+ put_unaligned_le32(crc, skb_put(skb, 4));
+
+ /* EEM packet header format:
+ * b0..13: length of ethernet frame
+ * b14: bmCRC (1 == valid Ethernet CRC)
+ * b15: bmType (0 == data)
+ */
+ len = skb->len;
+ put_unaligned_le16(BIT(14) | len, skb_push(skb, 2));
+
+ /* Bundle a zero length EEM packet if needed */
+ if (padlen)
+ put_unaligned_le16(0, skb_put(skb, 2));
+
+ return skb;
+}
+
+static int eem_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
+{
+ /*
+ * Our task here is to strip off framing, leaving skb with one
+ * data frame for the usbnet framework code to process. But we
+ * may have received multiple EEM payloads, or command payloads.
+ * So we must process _everything_ as if it's a header, except
+ * maybe the last data payload
+ *
+ * REVISIT the framework needs updating so that when we consume
+ * all payloads (the last or only message was a command, or a
+ * zero length EEM packet) that is not accounted as an rx_error.
+ */
+ do {
+ struct sk_buff *skb2 = NULL;
+ u16 header;
+ u16 len = 0;
+
+ /* incomplete EEM header? */
+ if (skb->len < EEM_HEAD)
+ return 0;
+
+ /*
+ * EEM packet header format:
+ * b0..14: EEM type dependant (Data or Command)
+ * b15: bmType
+ */
+ header = get_unaligned_le16(skb->data);
+ skb_pull(skb, EEM_HEAD);
+
+ /*
+ * The bmType bit helps to denote when EEM
+ * packet is data or command :
+ * bmType = 0 : EEM data payload
+ * bmType = 1 : EEM (link) command
+ */
+ if (header & BIT(15)) {
+ u16 bmEEMCmd;
+
+ /*
+ * EEM (link) command packet:
+ * b0..10: bmEEMCmdParam
+ * b11..13: bmEEMCmd
+ * b14: bmReserved (must be 0)
+ * b15: 1 (EEM command)
+ */
+ if (header & BIT(14)) {
+ devdbg(dev, "reserved command %04x\n", header);
+ continue;
+ }
+
+ bmEEMCmd = (header >> 11) & 0x7;
+ switch (bmEEMCmd) {
+
+ /* Responding to echo requests is mandatory. */
+ case 0: /* Echo command */
+ len = header & 0x7FF;
+
+ /* bogus command? */
+ if (skb->len < len)
+ return 0;
+
+ skb2 = skb_clone(skb, GFP_ATOMIC);
+ if (unlikely(!skb2))
+ goto next;
+ skb_trim(skb2, len);
+ put_unaligned_le16(BIT(15) | (1 << 11) | len,
+ skb_push(skb2, 2));
+ eem_linkcmd(dev, skb2);
+ break;
+
+ /*
+ * Host may choose to ignore hints.
+ * - suspend: peripheral ready to suspend
+ * - response: suggest N millisec polling
+ * - response complete: suggest N sec polling
+ */
+ case 2: /* Suspend hint */
+ case 3: /* Response hint */
+ case 4: /* Response complete hint */
+ continue;
+
+ /*
+ * Hosts should never receive host-to-peripheral
+ * or reserved command codes; or responses to an
+ * echo command we didn't send.
+ */
+ case 1: /* Echo response */
+ case 5: /* Tickle */
+ default: /* reserved */
+ devwarn(dev, "unexpected link command %d\n",
+ bmEEMCmd);
+ continue;
+ }
+
+ } else {
+ u32 crc, crc2;
+ int is_last;
+
+ /* zero length EEM packet? */
+ if (header == 0)
+ continue;
+
+ /*
+ * EEM data packet header :
+ * b0..13: length of ethernet frame
+ * b14: bmCRC
+ * b15: 0 (EEM data)
+ */
+ len = header & 0x3FFF;
+
+ /* bogus EEM payload? */
+ if (skb->len < len)
+ return 0;
+
+ /* bogus ethernet frame? */
+ if (len < (ETH_HLEN + ETH_FCS_LEN))
+ goto next;
+
+ /*
+ * Treat the last payload differently: framework
+ * code expects our "fixup" to have stripped off
+ * headers, so "skb" is a data packet (or error).
+ * Else if it's not the last payload, keep "skb"
+ * for further processing.
+ */
+ is_last = (len == skb->len);
+ if (is_last)
+ skb2 = skb;
+ else {
+ skb2 = skb_clone(skb, GFP_ATOMIC);
+ if (unlikely(!skb2))
+ return 0;
+ }
+
+ crc = get_unaligned_le32(skb2->data
+ + len - ETH_FCS_LEN);
+ skb_trim(skb2, len - ETH_FCS_LEN);
+
+ /*
+ * The bmCRC helps to denote when the CRC field in
+ * the Ethernet frame contains a calculated CRC:
+ * bmCRC = 1 : CRC is calculated
+ * bmCRC = 0 : CRC = 0xDEADBEEF
+ */
+ if (header & BIT(14))
+ crc2 = ~crc32_le(~0, skb2->data, len);
+ else
+ crc2 = 0xdeadbeef;
+
+ if (is_last)
+ return crc == crc2;
+
+ if (unlikely(crc != crc2)) {
+ dev->stats.rx_errors++;
+ dev_kfree_skb_any(skb2);
+ } else
+ usbnet_skb_return(dev, skb2);
+ }
+
+next:
+ skb_pull(skb, len);
+ } while (skb->len);
+
+ return 1;
+}
+
+static const struct driver_info eem_info = {
+ .description = "CDC EEM Device",
+ .flags = FLAG_ETHER,
+ .bind = eem_bind,
+ .rx_fixup = eem_rx_fixup,
+ .tx_fixup = eem_tx_fixup,
+};
+
+/*-------------------------------------------------------------------------*/
+
+static const struct usb_device_id products[] = {
+{
+ USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_EEM,
+ USB_CDC_PROTO_EEM),
+ .driver_info = (unsigned long) &eem_info,
+},
+{
+ /* EMPTY == end of list */
+},
+};
+MODULE_DEVICE_TABLE(usb, products);
+
+static struct usb_driver eem_driver = {
+ .name = "cdc_eem",
+ .id_table = products,
+ .probe = usbnet_probe,
+ .disconnect = usbnet_disconnect,
+ .suspend = usbnet_suspend,
+ .resume = usbnet_resume,
+};
+
+
+static int __init eem_init(void)
+{
+ return usb_register(&eem_driver);
+}
+module_init(eem_init);
+
+static void __exit eem_exit(void)
+{
+ usb_deregister(&eem_driver);
+}
+module_exit(eem_exit);
+
+MODULE_AUTHOR("Omar Laazimani <omar.oberthur@gmail.com>");
+MODULE_DESCRIPTION("USB CDC EEM");
+MODULE_LICENSE("GPL");