--- /dev/null
+/*
+ * USB network interface driver for Samsung Kalmia based LTE USB modem like the
+ * Samsung GT-B3730 and GT-B3710.
+ *
+ * Copyright (C) 2011 Marius Bjoernstad Kotsbak <marius@kotsbak.com>
+ *
+ * Sponsored by Quicklink Video Distribution Services Ltd.
+ *
+ * Based on the cdc_eem module.
+ *
+ * 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.
+ */
+
+#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>
+
+/*
+ * The Samsung Kalmia based LTE USB modems have a CDC ACM port for modem control
+ * handled by the "option" module and an ethernet data port handled by this
+ * module.
+ *
+ * The stick must first be switched into modem mode by usb_modeswitch
+ * or similar tool. Then the modem gets sent two initialization packets by
+ * this module, which gives the MAC address of the device. User space can then
+ * connect the modem using AT commands through the ACM port and then use
+ * DHCP on the network interface exposed by this module. Network packets are
+ * sent to and from the modem in a proprietary format discovered after watching
+ * the behavior of the windows driver for the modem.
+ *
+ * More information about the use of the modem is available in usb_modeswitch
+ * forum and the project page:
+ *
+ * http://www.draisberghof.de/usb_modeswitch/bb/viewtopic.php?t=465
+ * https://github.com/mkotsbak/Samsung-GT-B3730-linux-driver
+ */
+
+/* #define DEBUG */
+/* #define VERBOSE */
+
+#define KALMIA_HEADER_LENGTH 6
+#define KALMIA_ALIGN_SIZE 4
+#define KALMIA_USB_TIMEOUT 10000
+
+/*-------------------------------------------------------------------------*/
+
+static int
+kalmia_send_init_packet(struct usbnet *dev, u8 *init_msg, u8 init_msg_len,
+ u8 *buffer, u8 expected_len)
+{
+ int act_len;
+ int status;
+
+ netdev_dbg(dev->net, "Sending init packet");
+
+ status = usb_bulk_msg(dev->udev, usb_sndbulkpipe(dev->udev, 0x02),
+ init_msg, init_msg_len, &act_len, KALMIA_USB_TIMEOUT);
+ if (status != 0) {
+ netdev_err(dev->net,
+ "Error sending init packet. Status %i, length %i\n",
+ status, act_len);
+ return status;
+ }
+ else if (act_len != init_msg_len) {
+ netdev_err(dev->net,
+ "Did not send all of init packet. Bytes sent: %i",
+ act_len);
+ }
+ else {
+ netdev_dbg(dev->net, "Successfully sent init packet.");
+ }
+
+ status = usb_bulk_msg(dev->udev, usb_rcvbulkpipe(dev->udev, 0x81),
+ buffer, expected_len, &act_len, KALMIA_USB_TIMEOUT);
+
+ if (status != 0)
+ netdev_err(dev->net,
+ "Error receiving init result. Status %i, length %i\n",
+ status, act_len);
+ else if (act_len != expected_len)
+ netdev_err(dev->net, "Unexpected init result length: %i\n",
+ act_len);
+
+ return status;
+}
+
+static int
+kalmia_init_and_get_ethernet_addr(struct usbnet *dev, u8 *ethernet_addr)
+{
+ static const char init_msg_1[] =
+ { 0x57, 0x50, 0x04, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 0x00,
+ 0x00, 0x00 };
+ static const char init_msg_2[] =
+ { 0x57, 0x50, 0x04, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0xf4,
+ 0x00, 0x00 };
+ static const int buflen = 28;
+ char *usb_buf;
+ int status;
+
+ usb_buf = kmalloc(buflen, GFP_DMA | GFP_KERNEL);
+ if (!usb_buf)
+ return -ENOMEM;
+
+ memcpy(usb_buf, init_msg_1, 12);
+ status = kalmia_send_init_packet(dev, usb_buf, sizeof(init_msg_1)
+ / sizeof(init_msg_1[0]), usb_buf, 24);
+ if (status != 0)
+ return status;
+
+ memcpy(usb_buf, init_msg_2, 12);
+ status = kalmia_send_init_packet(dev, usb_buf, sizeof(init_msg_2)
+ / sizeof(init_msg_2[0]), usb_buf, 28);
+ if (status != 0)
+ return status;
+
+ memcpy(ethernet_addr, usb_buf + 10, ETH_ALEN);
+
+ kfree(usb_buf);
+ return status;
+}
+
+static int
+kalmia_bind(struct usbnet *dev, struct usb_interface *intf)
+{
+ int status;
+ u8 ethernet_addr[ETH_ALEN];
+
+ /* Don't bind to AT command interface */
+ if (intf->cur_altsetting->desc.bInterfaceClass != USB_CLASS_VENDOR_SPEC)
+ return -EINVAL;
+
+ dev->in = usb_rcvbulkpipe(dev->udev, 0x81 & USB_ENDPOINT_NUMBER_MASK);
+ dev->out = usb_sndbulkpipe(dev->udev, 0x02 & USB_ENDPOINT_NUMBER_MASK);
+ dev->status = NULL;
+
+ dev->net->hard_header_len += KALMIA_HEADER_LENGTH;
+ dev->hard_mtu = 1400;
+ dev->rx_urb_size = dev->hard_mtu * 10; // Found as optimal after testing
+
+ status = kalmia_init_and_get_ethernet_addr(dev, ethernet_addr);
+
+ if (status < 0) {
+ usb_set_intfdata(intf, NULL);
+ usb_driver_release_interface(driver_of(intf), intf);
+ return status;
+ }
+
+ memcpy(dev->net->dev_addr, ethernet_addr, ETH_ALEN);
+
+ return status;
+}
+
+static struct sk_buff *
+kalmia_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
+{
+ struct sk_buff *skb2 = NULL;
+ u16 content_len;
+ unsigned char *header_start;
+ unsigned char ether_type_1, ether_type_2;
+ u8 remainder, padlen = 0;
+
+ if (!skb_cloned(skb)) {
+ int headroom = skb_headroom(skb);
+ int tailroom = skb_tailroom(skb);
+
+ if ((tailroom >= KALMIA_ALIGN_SIZE) && (headroom
+ >= KALMIA_HEADER_LENGTH))
+ goto done;
+
+ if ((headroom + tailroom) > (KALMIA_HEADER_LENGTH
+ + KALMIA_ALIGN_SIZE)) {
+ skb->data = memmove(skb->head + KALMIA_HEADER_LENGTH,
+ skb->data, skb->len);
+ skb_set_tail_pointer(skb, skb->len);
+ goto done;
+ }
+ }
+
+ skb2 = skb_copy_expand(skb, KALMIA_HEADER_LENGTH,
+ KALMIA_ALIGN_SIZE, flags);
+ if (!skb2)
+ return NULL;
+
+ dev_kfree_skb_any(skb);
+ skb = skb2;
+
+done:
+ header_start = skb_push(skb, KALMIA_HEADER_LENGTH);
+ ether_type_1 = header_start[KALMIA_HEADER_LENGTH + 12];
+ ether_type_2 = header_start[KALMIA_HEADER_LENGTH + 13];
+
+ netdev_dbg(dev->net, "Sending etherType: %02x%02x", ether_type_1,
+ ether_type_2);
+
+ /* According to empiric data for data packages */
+ header_start[0] = 0x57;
+ header_start[1] = 0x44;
+ content_len = skb->len - KALMIA_HEADER_LENGTH;
+
+ put_unaligned_le16(content_len, &header_start[2]);
+ header_start[4] = ether_type_1;
+ header_start[5] = ether_type_2;
+
+ /* Align to 4 bytes by padding with zeros */
+ remainder = skb->len % KALMIA_ALIGN_SIZE;
+ if (remainder > 0) {
+ padlen = KALMIA_ALIGN_SIZE - remainder;
+ memset(skb_put(skb, padlen), 0, padlen);
+ }
+
+ netdev_dbg(dev->net,
+ "Sending package with length %i and padding %i. Header: %6phC.",
+ content_len, padlen, header_start);
+
+ return skb;
+}
+
+static int
+kalmia_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.
+ */
+ static const u8 HEADER_END_OF_USB_PACKET[] =
+ { 0x57, 0x5a, 0x00, 0x00, 0x08, 0x00 };
+ static const u8 EXPECTED_UNKNOWN_HEADER_1[] =
+ { 0x57, 0x43, 0x1e, 0x00, 0x15, 0x02 };
+ static const u8 EXPECTED_UNKNOWN_HEADER_2[] =
+ { 0x57, 0x50, 0x0e, 0x00, 0x00, 0x00 };
+ int i = 0;
+
+ /* incomplete header? */
+ if (skb->len < KALMIA_HEADER_LENGTH)
+ return 0;
+
+ do {
+ struct sk_buff *skb2 = NULL;
+ u8 *header_start;
+ u16 usb_packet_length, ether_packet_length;
+ int is_last;
+
+ header_start = skb->data;
+
+ if (unlikely(header_start[0] != 0x57 || header_start[1] != 0x44)) {
+ if (!memcmp(header_start, EXPECTED_UNKNOWN_HEADER_1,
+ sizeof(EXPECTED_UNKNOWN_HEADER_1)) || !memcmp(
+ header_start, EXPECTED_UNKNOWN_HEADER_2,
+ sizeof(EXPECTED_UNKNOWN_HEADER_2))) {
+ netdev_dbg(dev->net,
+ "Received expected unknown frame header: %6phC. Package length: %i\n",
+ header_start,
+ skb->len - KALMIA_HEADER_LENGTH);
+ }
+ else {
+ netdev_err(dev->net,
+ "Received unknown frame header: %6phC. Package length: %i\n",
+ header_start,
+ skb->len - KALMIA_HEADER_LENGTH);
+ return 0;
+ }
+ }
+ else
+ netdev_dbg(dev->net,
+ "Received header: %6phC. Package length: %i\n",
+ header_start, skb->len - KALMIA_HEADER_LENGTH);
+
+ /* subtract start header and end header */
+ usb_packet_length = skb->len - (2 * KALMIA_HEADER_LENGTH);
+ ether_packet_length = get_unaligned_le16(&header_start[2]);
+ skb_pull(skb, KALMIA_HEADER_LENGTH);
+
+ /* Some small packets misses end marker */
+ if (usb_packet_length < ether_packet_length) {
+ ether_packet_length = usb_packet_length
+ + KALMIA_HEADER_LENGTH;
+ is_last = true;
+ }
+ else {
+ netdev_dbg(dev->net, "Correct package length #%i", i
+ + 1);
+
+ is_last = (memcmp(skb->data + ether_packet_length,
+ HEADER_END_OF_USB_PACKET,
+ sizeof(HEADER_END_OF_USB_PACKET)) == 0);
+ if (!is_last) {
+ header_start = skb->data + ether_packet_length;
+ netdev_dbg(dev->net,
+ "End header: %6phC. Package length: %i\n",
+ header_start,
+ skb->len - KALMIA_HEADER_LENGTH);
+ }
+ }
+
+ if (is_last) {
+ skb2 = skb;
+ }
+ else {
+ skb2 = skb_clone(skb, GFP_ATOMIC);
+ if (unlikely(!skb2))
+ return 0;
+ }
+
+ skb_trim(skb2, ether_packet_length);
+
+ if (is_last) {
+ return 1;
+ }
+ else {
+ usbnet_skb_return(dev, skb2);
+ skb_pull(skb, ether_packet_length);
+ }
+
+ i++;
+ }
+ while (skb->len);
+
+ return 1;
+}
+
+static const struct driver_info kalmia_info = {
+ .description = "Samsung Kalmia LTE USB dongle",
+ .flags = FLAG_WWAN,
+ .bind = kalmia_bind,
+ .rx_fixup = kalmia_rx_fixup,
+ .tx_fixup = kalmia_tx_fixup
+};
+
+/*-------------------------------------------------------------------------*/
+
+static const struct usb_device_id products[] = {
+ /* The unswitched USB ID, to get the module auto loaded: */
+ { USB_DEVICE(0x04e8, 0x689a) },
+ /* The stick swithed into modem (by e.g. usb_modeswitch): */
+ { USB_DEVICE(0x04e8, 0x6889),
+ .driver_info = (unsigned long) &kalmia_info, },
+ { /* EMPTY == end of list */} };
+MODULE_DEVICE_TABLE( usb, products);
+
+static struct usb_driver kalmia_driver = {
+ .name = "kalmia",
+ .id_table = products,
+ .probe = usbnet_probe,
+ .disconnect = usbnet_disconnect,
+ .suspend = usbnet_suspend,
+ .resume = usbnet_resume,
+ .disable_hub_initiated_lpm = 1,
+};
+
+module_usb_driver(kalmia_driver);
+
+MODULE_AUTHOR("Marius Bjoernstad Kotsbak <marius@kotsbak.com>");
+MODULE_DESCRIPTION("Samsung Kalmia USB network driver");
+MODULE_LICENSE("GPL");
Code Review / kvmfornfv.git / blobdiff