diff options
Diffstat (limited to 'drivers/net/usb/cdc_eem.c')
| -rw-r--r-- | drivers/net/usb/cdc_eem.c | 377 |
1 files changed, 377 insertions, 0 deletions
diff --git a/drivers/net/usb/cdc_eem.c b/drivers/net/usb/cdc_eem.c new file mode 100644 index 00000000..685a4e22 --- /dev/null +++ b/drivers/net/usb/cdc_eem.c @@ -0,0 +1,377 @@ +/* + * 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> +#include <linux/gfp.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); + netdev_warn(dev->net, "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; + dev->hard_mtu = dev->net->mtu + dev->net->hard_header_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 dependent (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)) { + netdev_dbg(dev->net, "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 */ + netdev_warn(dev->net, + "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; + } + + /* + * 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)) { + crc = get_unaligned_le32(skb2->data + + len - ETH_FCS_LEN); + crc2 = ~crc32_le(~0, skb2->data, skb2->len + - ETH_FCS_LEN); + } else { + crc = get_unaligned_be32(skb2->data + + len - ETH_FCS_LEN); + crc2 = 0xdeadbeef; + } + skb_trim(skb2, len - ETH_FCS_LEN); + + if (is_last) + return crc == crc2; + + if (unlikely(crc != crc2)) { + dev->net->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 | FLAG_POINTTOPOINT, + .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, +}; + +module_usb_driver(eem_driver); + +MODULE_AUTHOR("Omar Laazimani <omar.oberthur@gmail.com>"); +MODULE_DESCRIPTION("USB CDC EEM"); +MODULE_LICENSE("GPL"); |