diff options
Diffstat (limited to 'drivers/net/usb/kalmia.c')
| -rw-r--r-- | drivers/net/usb/kalmia.c | 358 |
1 files changed, 358 insertions, 0 deletions
diff --git a/drivers/net/usb/kalmia.c b/drivers/net/usb/kalmia.c new file mode 100644 index 000000000..613fc6910 --- /dev/null +++ b/drivers/net/usb/kalmia.c @@ -0,0 +1,358 @@ +// 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; + + eth_hw_addr_set(dev->net, ethernet_addr); + + 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"); |