|  | // 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"); |