| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* |
| * 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. |
| */ |
| |
| #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\n", |
| status); |
| 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\n", |
| status); |
| 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, ARRAY_SIZE(init_msg_1), |
| usb_buf, 24); |
| if (status != 0) |
| goto out; |
| |
| memcpy(usb_buf, init_msg_2, 12); |
| status = kalmia_send_init_packet(dev, usb_buf, ARRAY_SIZE(init_msg_2), |
| usb_buf, 28); |
| if (status != 0) |
| goto out; |
| |
| memcpy(ethernet_addr, usb_buf + 10, ETH_ALEN); |
| out: |
| 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) |
| 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; |
| skb_put_zero(skb, 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 switched 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"); |