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Diffstat (limited to 'drivers/net/usb/cdc_eem.c')
-rw-r--r--drivers/net/usb/cdc_eem.c366
1 files changed, 366 insertions, 0 deletions
diff --git a/drivers/net/usb/cdc_eem.c b/drivers/net/usb/cdc_eem.c
new file mode 100644
index 000000000..baa9b14b1
--- /dev/null
+++ b/drivers/net/usb/cdc_eem.c
@@ -0,0 +1,366 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * USB CDC EEM network interface driver
+ * Copyright (C) 2009 Oberthur Technologies
+ * by Omar Laazimani, Olivier Condemine
+ */
+
+#include <linux/module.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>
+#include <linux/if_vlan.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 https://usb.org/sites/default/files/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)
+ return status;
+
+ /* no jumbogram (16K) support for now */
+
+ dev->net->hard_header_len += EEM_HEAD + ETH_FCS_LEN + VLAN_HLEN;
+ 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);
+ dev_kfree_skb_any(skb);
+ if (!skb2)
+ return NULL;
+
+ 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) | BIT(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
+ *
+ * Suspend is reported and maybe heeded.
+ */
+ case 2: /* Suspend hint */
+ usbnet_device_suggests_idle(dev);
+ continue;
+ 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,
+ .disable_hub_initiated_lpm = 1,
+};
+
+module_usb_driver(eem_driver);
+
+MODULE_AUTHOR("Omar Laazimani <omar.oberthur@gmail.com>");
+MODULE_DESCRIPTION("USB CDC EEM");
+MODULE_LICENSE("GPL");
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-25 02:17:42 +0000