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linux-zen-desktop/drivers/net/can/usb/ucan.c

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Initial commit
2023-08-30 17:31:07 +02:00
// SPDX-License-Identifier: GPL-2.0
/* Driver for Theobroma Systems UCAN devices, Protocol Version 3
*
* Copyright (C) 2018 Theobroma Systems Design und Consulting GmbH
*
*
* General Description:
*
* The USB Device uses three Endpoints:
*
* CONTROL Endpoint: Is used the setup the device (start, stop,
* info, configure).
*
* IN Endpoint: The device sends CAN Frame Messages and Device
* Information using the IN endpoint.
*
* OUT Endpoint: The driver sends configuration requests, and CAN
* Frames on the out endpoint.
*
* Error Handling:
*
* If error reporting is turned on the device encodes error into CAN
* error frames (see uapi/linux/can/error.h) and sends it using the
* IN Endpoint. The driver updates statistics and forward it.
*/
#include <linux/can.h>
#include <linux/can/dev.h>
#include <linux/can/error.h>
#include <linux/ethtool.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/signal.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/usb.h>
#define UCAN_DRIVER_NAME "ucan"
#define UCAN_MAX_RX_URBS 8
/* the CAN controller needs a while to enable/disable the bus */
#define UCAN_USB_CTL_PIPE_TIMEOUT 1000
/* this driver currently supports protocol version 3 only */
#define UCAN_PROTOCOL_VERSION_MIN 3
#define UCAN_PROTOCOL_VERSION_MAX 3
/* UCAN Message Definitions
* ------------------------
*
* ucan_message_out_t and ucan_message_in_t define the messages
* transmitted on the OUT and IN endpoint.
*
* Multibyte fields are transmitted with little endianness
*
* INTR Endpoint: a single uint32_t storing the current space in the fifo
*
* OUT Endpoint: single message of type ucan_message_out_t is
* transmitted on the out endpoint
*
* IN Endpoint: multiple messages ucan_message_in_t concateted in
* the following way:
*
* m[n].len <=> the length if message n(including the header in bytes)
* m[n] is is aligned to a 4 byte boundary, hence
* offset(m[0]) := 0;
* offset(m[n+1]) := offset(m[n]) + (m[n].len + 3) & 3
*
* this implies that
* offset(m[n]) % 4 <=> 0
*/
/* Device Global Commands */
enum {
UCAN_DEVICE_GET_FW_STRING = 0,
};
/* UCAN Commands */
enum {
/* start the can transceiver - val defines the operation mode */
UCAN_COMMAND_START = 0,
/* cancel pending transmissions and stop the can transceiver */
UCAN_COMMAND_STOP = 1,
/* send can transceiver into low-power sleep mode */
UCAN_COMMAND_SLEEP = 2,
/* wake up can transceiver from low-power sleep mode */
UCAN_COMMAND_WAKEUP = 3,
/* reset the can transceiver */
UCAN_COMMAND_RESET = 4,
/* get piece of info from the can transceiver - subcmd defines what
* piece
*/
UCAN_COMMAND_GET = 5,
/* clear or disable hardware filter - subcmd defines which of the two */
UCAN_COMMAND_FILTER = 6,
/* Setup bittiming */
UCAN_COMMAND_SET_BITTIMING = 7,
/* recover from bus-off state */
UCAN_COMMAND_RESTART = 8,
};
/* UCAN_COMMAND_START and UCAN_COMMAND_GET_INFO operation modes (bitmap).
* Undefined bits must be set to 0.
*/
enum {
UCAN_MODE_LOOPBACK = BIT(0),
UCAN_MODE_SILENT = BIT(1),
UCAN_MODE_3_SAMPLES = BIT(2),
UCAN_MODE_ONE_SHOT = BIT(3),
UCAN_MODE_BERR_REPORT = BIT(4),
};
/* UCAN_COMMAND_GET subcommands */
enum {
UCAN_COMMAND_GET_INFO = 0,
UCAN_COMMAND_GET_PROTOCOL_VERSION = 1,
};
/* UCAN_COMMAND_FILTER subcommands */
enum {
UCAN_FILTER_CLEAR = 0,
UCAN_FILTER_DISABLE = 1,
UCAN_FILTER_ENABLE = 2,
};
/* OUT endpoint message types */
enum {
UCAN_OUT_TX = 2, /* transmit a CAN frame */
};
/* IN endpoint message types */
enum {
UCAN_IN_TX_COMPLETE = 1, /* CAN frame transmission completed */
UCAN_IN_RX = 2, /* CAN frame received */
};
struct ucan_ctl_cmd_start {
__le16 mode; /* OR-ing any of UCAN_MODE_* */
} __packed;
struct ucan_ctl_cmd_set_bittiming {
__le32 tq; /* Time quanta (TQ) in nanoseconds */
__le16 brp; /* TQ Prescaler */
__le16 sample_point; /* Samplepoint on tenth percent */
u8 prop_seg; /* Propagation segment in TQs */
u8 phase_seg1; /* Phase buffer segment 1 in TQs */
u8 phase_seg2; /* Phase buffer segment 2 in TQs */
u8 sjw; /* Synchronisation jump width in TQs */
} __packed;
struct ucan_ctl_cmd_device_info {
__le32 freq; /* Clock Frequency for tq generation */
u8 tx_fifo; /* Size of the transmission fifo */
u8 sjw_max; /* can_bittiming fields... */
u8 tseg1_min;
u8 tseg1_max;
u8 tseg2_min;
u8 tseg2_max;
__le16 brp_inc;
__le32 brp_min;
__le32 brp_max; /* ...can_bittiming fields */
__le16 ctrlmodes; /* supported control modes */
__le16 hwfilter; /* Number of HW filter banks */
__le16 rxmboxes; /* Number of receive Mailboxes */
} __packed;
struct ucan_ctl_cmd_get_protocol_version {
__le32 version;
} __packed;
union ucan_ctl_payload {
/* Setup Bittiming
* bmRequest == UCAN_COMMAND_START
*/
struct ucan_ctl_cmd_start cmd_start;
/* Setup Bittiming
* bmRequest == UCAN_COMMAND_SET_BITTIMING
*/
struct ucan_ctl_cmd_set_bittiming cmd_set_bittiming;
/* Get Device Information
* bmRequest == UCAN_COMMAND_GET; wValue = UCAN_COMMAND_GET_INFO
*/
struct ucan_ctl_cmd_device_info cmd_get_device_info;
/* Get Protocol Version
* bmRequest == UCAN_COMMAND_GET;
* wValue = UCAN_COMMAND_GET_PROTOCOL_VERSION
*/
struct ucan_ctl_cmd_get_protocol_version cmd_get_protocol_version;
u8 raw[128];
} __packed;
enum {
UCAN_TX_COMPLETE_SUCCESS = BIT(0),
};
/* Transmission Complete within ucan_message_in */
struct ucan_tx_complete_entry_t {
u8 echo_index;
u8 flags;
} __packed __aligned(0x2);
/* CAN Data message format within ucan_message_in/out */
struct ucan_can_msg {
/* note DLC is computed by
* msg.len - sizeof (msg.len)
* - sizeof (msg.type)
* - sizeof (msg.can_msg.id)
*/
__le32 id;
union {
u8 data[CAN_MAX_DLEN]; /* Data of CAN frames */
u8 dlc; /* RTR dlc */
};
} __packed;
/* OUT Endpoint, outbound messages */
struct ucan_message_out {
__le16 len; /* Length of the content include header */
u8 type; /* UCAN_OUT_TX and friends */
u8 subtype; /* command sub type */
union {
/* Transmit CAN frame
* (type == UCAN_TX) && ((msg.can_msg.id & CAN_RTR_FLAG) == 0)
* subtype stores the echo id
*/
struct ucan_can_msg can_msg;
} msg;
} __packed __aligned(0x4);
/* IN Endpoint, inbound messages */
struct ucan_message_in {
__le16 len; /* Length of the content include header */
u8 type; /* UCAN_IN_RX and friends */
u8 subtype; /* command sub type */
union {
/* CAN Frame received
* (type == UCAN_IN_RX)
* && ((msg.can_msg.id & CAN_RTR_FLAG) == 0)
*/
struct ucan_can_msg can_msg;
/* CAN transmission complete
* (type == UCAN_IN_TX_COMPLETE)
*/
DECLARE_FLEX_ARRAY(struct ucan_tx_complete_entry_t,
can_tx_complete_msg);
} __aligned(0x4) msg;
} __packed __aligned(0x4);
/* Macros to calculate message lengths */
#define UCAN_OUT_HDR_SIZE offsetof(struct ucan_message_out, msg)
#define UCAN_IN_HDR_SIZE offsetof(struct ucan_message_in, msg)
#define UCAN_IN_LEN(member) (UCAN_OUT_HDR_SIZE + sizeof(member))
struct ucan_priv;
/* Context Information for transmission URBs */
struct ucan_urb_context {
struct ucan_priv *up;
bool allocated;
};
/* Information reported by the USB device */
struct ucan_device_info {
struct can_bittiming_const bittiming_const;
u8 tx_fifo;
};
/* Driver private data */
struct ucan_priv {
/* must be the first member */
struct can_priv can;
/* linux USB device structures */
struct usb_device *udev;
struct net_device *netdev;
/* lock for can->echo_skb (used around
* can_put/get/free_echo_skb
*/
spinlock_t echo_skb_lock;
/* usb device information information */
u8 intf_index;
u8 in_ep_addr;
u8 out_ep_addr;
u16 in_ep_size;
/* transmission and reception buffers */
struct usb_anchor rx_urbs;
struct usb_anchor tx_urbs;
union ucan_ctl_payload *ctl_msg_buffer;
struct ucan_device_info device_info;
/* transmission control information and locks */
spinlock_t context_lock;
unsigned int available_tx_urbs;
struct ucan_urb_context *context_array;
};
static u8 ucan_can_cc_dlc2len(struct ucan_can_msg *msg, u16 len)
{
if (le32_to_cpu(msg->id) & CAN_RTR_FLAG)
return can_cc_dlc2len(msg->dlc);
else
return can_cc_dlc2len(len - (UCAN_IN_HDR_SIZE + sizeof(msg->id)));
}
static void ucan_release_context_array(struct ucan_priv *up)
{
if (!up->context_array)
return;
/* lock is not needed because, driver is currently opening or closing */
up->available_tx_urbs = 0;
kfree(up->context_array);
up->context_array = NULL;
}
static int ucan_alloc_context_array(struct ucan_priv *up)
{
int i;
/* release contexts if any */
ucan_release_context_array(up);
up->context_array = kcalloc(up->device_info.tx_fifo,
sizeof(*up->context_array),
GFP_KERNEL);
if (!up->context_array) {
netdev_err(up->netdev,
"Not enough memory to allocate tx contexts\n");
return -ENOMEM;
}
for (i = 0; i < up->device_info.tx_fifo; i++) {
up->context_array[i].allocated = false;
up->context_array[i].up = up;
}
/* lock is not needed because, driver is currently opening */
up->available_tx_urbs = up->device_info.tx_fifo;
return 0;
}
static struct ucan_urb_context *ucan_alloc_context(struct ucan_priv *up)
{
int i;
unsigned long flags;
struct ucan_urb_context *ret = NULL;
if (WARN_ON_ONCE(!up->context_array))
return NULL;
/* execute context operation atomically */
spin_lock_irqsave(&up->context_lock, flags);
for (i = 0; i < up->device_info.tx_fifo; i++) {
if (!up->context_array[i].allocated) {
/* update context */
ret = &up->context_array[i];
up->context_array[i].allocated = true;
/* stop queue if necessary */
up->available_tx_urbs--;
if (!up->available_tx_urbs)
netif_stop_queue(up->netdev);
break;
}
}
spin_unlock_irqrestore(&up->context_lock, flags);
return ret;
}
static bool ucan_release_context(struct ucan_priv *up,
struct ucan_urb_context *ctx)
{
unsigned long flags;
bool ret = false;
if (WARN_ON_ONCE(!up->context_array))
return false;
/* execute context operation atomically */
spin_lock_irqsave(&up->context_lock, flags);
/* context was not allocated, maybe the device sent garbage */
if (ctx->allocated) {
ctx->allocated = false;
/* check if the queue needs to be woken */
if (!up->available_tx_urbs)
netif_wake_queue(up->netdev);
up->available_tx_urbs++;
ret = true;
}
spin_unlock_irqrestore(&up->context_lock, flags);
return ret;
}
static int ucan_ctrl_command_out(struct ucan_priv *up,
u8 cmd, u16 subcmd, u16 datalen)
{
return usb_control_msg(up->udev,
usb_sndctrlpipe(up->udev, 0),
cmd,
USB_DIR_OUT | USB_TYPE_VENDOR |
USB_RECIP_INTERFACE,
subcmd,
up->intf_index,
up->ctl_msg_buffer,
datalen,
UCAN_USB_CTL_PIPE_TIMEOUT);
}
static int ucan_device_request_in(struct ucan_priv *up,
u8 cmd, u16 subcmd, u16 datalen)
{
return usb_control_msg(up->udev,
usb_rcvctrlpipe(up->udev, 0),
cmd,
USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
subcmd,
0,
up->ctl_msg_buffer,
datalen,
UCAN_USB_CTL_PIPE_TIMEOUT);
}
/* Parse the device information structure reported by the device and
* setup private variables accordingly
*/
static void ucan_parse_device_info(struct ucan_priv *up,
struct ucan_ctl_cmd_device_info *device_info)
{
struct can_bittiming_const *bittiming =
&up->device_info.bittiming_const;
u16 ctrlmodes;
/* store the data */
up->can.clock.freq = le32_to_cpu(device_info->freq);
up->device_info.tx_fifo = device_info->tx_fifo;
strcpy(bittiming->name, "ucan");
bittiming->tseg1_min = device_info->tseg1_min;
bittiming->tseg1_max = device_info->tseg1_max;
bittiming->tseg2_min = device_info->tseg2_min;
bittiming->tseg2_max = device_info->tseg2_max;
bittiming->sjw_max = device_info->sjw_max;
bittiming->brp_min = le32_to_cpu(device_info->brp_min);
bittiming->brp_max = le32_to_cpu(device_info->brp_max);
bittiming->brp_inc = le16_to_cpu(device_info->brp_inc);
ctrlmodes = le16_to_cpu(device_info->ctrlmodes);
up->can.ctrlmode_supported = 0;
if (ctrlmodes & UCAN_MODE_LOOPBACK)
up->can.ctrlmode_supported |= CAN_CTRLMODE_LOOPBACK;
if (ctrlmodes & UCAN_MODE_SILENT)
up->can.ctrlmode_supported |= CAN_CTRLMODE_LISTENONLY;
if (ctrlmodes & UCAN_MODE_3_SAMPLES)
up->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
if (ctrlmodes & UCAN_MODE_ONE_SHOT)
up->can.ctrlmode_supported |= CAN_CTRLMODE_ONE_SHOT;
if (ctrlmodes & UCAN_MODE_BERR_REPORT)
up->can.ctrlmode_supported |= CAN_CTRLMODE_BERR_REPORTING;
}
/* Handle a CAN error frame that we have received from the device.
* Returns true if the can state has changed.
*/
static bool ucan_handle_error_frame(struct ucan_priv *up,
struct ucan_message_in *m,
canid_t canid)
{
enum can_state new_state = up->can.state;
struct net_device_stats *net_stats = &up->netdev->stats;
struct can_device_stats *can_stats = &up->can.can_stats;
if (canid & CAN_ERR_LOSTARB)
can_stats->arbitration_lost++;
if (canid & CAN_ERR_BUSERROR)
can_stats->bus_error++;
if (canid & CAN_ERR_ACK)
net_stats->tx_errors++;
if (canid & CAN_ERR_BUSOFF)
new_state = CAN_STATE_BUS_OFF;
/* controller problems, details in data[1] */
if (canid & CAN_ERR_CRTL) {
u8 d1 = m->msg.can_msg.data[1];
if (d1 & CAN_ERR_CRTL_RX_OVERFLOW)
net_stats->rx_over_errors++;
/* controller state bits: if multiple are set the worst wins */
if (d1 & CAN_ERR_CRTL_ACTIVE)
new_state = CAN_STATE_ERROR_ACTIVE;
if (d1 & (CAN_ERR_CRTL_RX_WARNING | CAN_ERR_CRTL_TX_WARNING))
new_state = CAN_STATE_ERROR_WARNING;
if (d1 & (CAN_ERR_CRTL_RX_PASSIVE | CAN_ERR_CRTL_TX_PASSIVE))
new_state = CAN_STATE_ERROR_PASSIVE;
}
/* protocol error, details in data[2] */
if (canid & CAN_ERR_PROT) {
u8 d2 = m->msg.can_msg.data[2];
if (d2 & CAN_ERR_PROT_TX)
net_stats->tx_errors++;
else
net_stats->rx_errors++;
}
/* no state change - we are done */
if (up->can.state == new_state)
return false;
/* we switched into a better state */
if (up->can.state > new_state) {
up->can.state = new_state;
return true;
}
/* we switched into a worse state */
up->can.state = new_state;
switch (new_state) {
case CAN_STATE_BUS_OFF:
can_stats->bus_off++;
can_bus_off(up->netdev);
break;
case CAN_STATE_ERROR_PASSIVE:
can_stats->error_passive++;
break;
case CAN_STATE_ERROR_WARNING:
can_stats->error_warning++;
break;
default:
break;
}
return true;
}
/* Callback on reception of a can frame via the IN endpoint
*
* This function allocates an skb and transferres it to the Linux
* network stack
*/
static void ucan_rx_can_msg(struct ucan_priv *up, struct ucan_message_in *m)
{
int len;
canid_t canid;
struct can_frame *cf;
struct sk_buff *skb;
struct net_device_stats *stats = &up->netdev->stats;
/* get the contents of the length field */
len = le16_to_cpu(m->len);
/* check sanity */
if (len < UCAN_IN_HDR_SIZE + sizeof(m->msg.can_msg.id)) {
netdev_warn(up->netdev, "invalid input message len: %d\n", len);
return;
}
/* handle error frames */
canid = le32_to_cpu(m->msg.can_msg.id);
if (canid & CAN_ERR_FLAG) {
bool busstate_changed = ucan_handle_error_frame(up, m, canid);
/* if berr-reporting is off only state changes get through */
if (!(up->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING) &&
!busstate_changed)
return;
} else {
canid_t canid_mask;
/* compute the mask for canid */
canid_mask = CAN_RTR_FLAG;
if (canid & CAN_EFF_FLAG)
canid_mask |= CAN_EFF_MASK | CAN_EFF_FLAG;
else
canid_mask |= CAN_SFF_MASK;
if (canid & ~canid_mask)
netdev_warn(up->netdev,
"unexpected bits set (canid %x, mask %x)",
canid, canid_mask);
canid &= canid_mask;
}
/* allocate skb */
skb = alloc_can_skb(up->netdev, &cf);
if (!skb)
return;
/* fill the can frame */
cf->can_id = canid;
/* compute DLC taking RTR_FLAG into account */
cf->len = ucan_can_cc_dlc2len(&m->msg.can_msg, len);
/* copy the payload of non RTR frames */
if (!(cf->can_id & CAN_RTR_FLAG) || (cf->can_id & CAN_ERR_FLAG))
memcpy(cf->data, m->msg.can_msg.data, cf->len);
/* don't count error frames as real packets */
if (!(cf->can_id & CAN_ERR_FLAG)) {
stats->rx_packets++;
if (!(cf->can_id & CAN_RTR_FLAG))
stats->rx_bytes += cf->len;
}
/* pass it to Linux */
netif_rx(skb);
}
/* callback indicating completed transmission */
static void ucan_tx_complete_msg(struct ucan_priv *up,
struct ucan_message_in *m)
{
unsigned long flags;
u16 count, i;
u8 echo_index;
u16 len = le16_to_cpu(m->len);
struct ucan_urb_context *context;
if (len < UCAN_IN_HDR_SIZE || (len % 2 != 0)) {
netdev_err(up->netdev, "invalid tx complete length\n");
return;
}
count = (len - UCAN_IN_HDR_SIZE) / 2;
for (i = 0; i < count; i++) {
/* we did not submit such echo ids */
echo_index = m->msg.can_tx_complete_msg[i].echo_index;
if (echo_index >= up->device_info.tx_fifo) {
up->netdev->stats.tx_errors++;
netdev_err(up->netdev,
"invalid echo_index %d received\n",
echo_index);
continue;
}
/* gather information from the context */
context = &up->context_array[echo_index];
/* Release context and restart queue if necessary.
* Also check if the context was allocated
*/
if (!ucan_release_context(up, context))
continue;
spin_lock_irqsave(&up->echo_skb_lock, flags);
if (m->msg.can_tx_complete_msg[i].flags &
UCAN_TX_COMPLETE_SUCCESS) {
/* update statistics */
up->netdev->stats.tx_packets++;
up->netdev->stats.tx_bytes +=
can_get_echo_skb(up->netdev, echo_index, NULL);
} else {
up->netdev->stats.tx_dropped++;
can_free_echo_skb(up->netdev, echo_index, NULL);
}
spin_unlock_irqrestore(&up->echo_skb_lock, flags);
}
}
/* callback on reception of a USB message */
static void ucan_read_bulk_callback(struct urb *urb)
{
int ret;
int pos;
struct ucan_priv *up = urb->context;
struct net_device *netdev = up->netdev;
struct ucan_message_in *m;
/* the device is not up and the driver should not receive any
* data on the bulk in pipe
*/
if (WARN_ON(!up->context_array)) {
usb_free_coherent(up->udev,
up->in_ep_size,
urb->transfer_buffer,
urb->transfer_dma);
return;
}
/* check URB status */
switch (urb->status) {
case 0:
break;
case -ENOENT:
case -EPIPE:
case -EPROTO:
case -ESHUTDOWN:
case -ETIME:
/* urb is not resubmitted -> free dma data */
usb_free_coherent(up->udev,
up->in_ep_size,
urb->transfer_buffer,
urb->transfer_dma);
netdev_dbg(up->netdev, "not resubmitting urb; status: %d\n",
urb->status);
return;
default:
goto resubmit;
}
/* sanity check */
if (!netif_device_present(netdev))
return;
/* iterate over input */
pos = 0;
while (pos < urb->actual_length) {
int len;
/* check sanity (length of header) */
if ((urb->actual_length - pos) < UCAN_IN_HDR_SIZE) {
netdev_warn(up->netdev,
"invalid message (short; no hdr; l:%d)\n",
urb->actual_length);
goto resubmit;
}
/* setup the message address */
m = (struct ucan_message_in *)
((u8 *)urb->transfer_buffer + pos);
len = le16_to_cpu(m->len);
/* check sanity (length of content) */
if (urb->actual_length - pos < len) {
netdev_warn(up->netdev,
"invalid message (short; no data; l:%d)\n",
urb->actual_length);
print_hex_dump(KERN_WARNING,
"raw data: ",
DUMP_PREFIX_ADDRESS,
16,
1,
urb->transfer_buffer,
urb->actual_length,
true);
goto resubmit;
}
switch (m->type) {
case UCAN_IN_RX:
ucan_rx_can_msg(up, m);
break;
case UCAN_IN_TX_COMPLETE:
ucan_tx_complete_msg(up, m);
break;
default:
netdev_warn(up->netdev,
"invalid message (type; t:%d)\n",
m->type);
break;
}
/* proceed to next message */
pos += len;
/* align to 4 byte boundary */
pos = round_up(pos, 4);
}
resubmit:
/* resubmit urb when done */
usb_fill_bulk_urb(urb, up->udev,
usb_rcvbulkpipe(up->udev,
up->in_ep_addr),
urb->transfer_buffer,
up->in_ep_size,
ucan_read_bulk_callback,
up);
usb_anchor_urb(urb, &up->rx_urbs);
ret = usb_submit_urb(urb, GFP_ATOMIC);
if (ret < 0) {
netdev_err(up->netdev,
"failed resubmitting read bulk urb: %d\n",
ret);
usb_unanchor_urb(urb);
usb_free_coherent(up->udev,
up->in_ep_size,
urb->transfer_buffer,
urb->transfer_dma);
if (ret == -ENODEV)
netif_device_detach(netdev);
}
}
/* callback after transmission of a USB message */
static void ucan_write_bulk_callback(struct urb *urb)
{
unsigned long flags;
struct ucan_priv *up;
struct ucan_urb_context *context = urb->context;
/* get the urb context */
if (WARN_ON_ONCE(!context))
return;
/* free up our allocated buffer */
usb_free_coherent(urb->dev,
sizeof(struct ucan_message_out),
urb->transfer_buffer,
urb->transfer_dma);
up = context->up;
if (WARN_ON_ONCE(!up))
return;
/* sanity check */
if (!netif_device_present(up->netdev))
return;
/* transmission failed (USB - the device will not send a TX complete) */
if (urb->status) {
netdev_warn(up->netdev,
"failed to transmit USB message to device: %d\n",
urb->status);
/* update counters an cleanup */
spin_lock_irqsave(&up->echo_skb_lock, flags);
can_free_echo_skb(up->netdev, context - up->context_array, NULL);
spin_unlock_irqrestore(&up->echo_skb_lock, flags);
up->netdev->stats.tx_dropped++;
/* release context and restart the queue if necessary */
if (!ucan_release_context(up, context))
netdev_err(up->netdev,
"urb failed, failed to release context\n");
}
}
static void ucan_cleanup_rx_urbs(struct ucan_priv *up, struct urb **urbs)
{
int i;
for (i = 0; i < UCAN_MAX_RX_URBS; i++) {
if (urbs[i]) {
usb_unanchor_urb(urbs[i]);
usb_free_coherent(up->udev,
up->in_ep_size,
urbs[i]->transfer_buffer,
urbs[i]->transfer_dma);
usb_free_urb(urbs[i]);
}
}
memset(urbs, 0, sizeof(*urbs) * UCAN_MAX_RX_URBS);
}
static int ucan_prepare_and_anchor_rx_urbs(struct ucan_priv *up,
struct urb **urbs)
{
int i;
memset(urbs, 0, sizeof(*urbs) * UCAN_MAX_RX_URBS);
for (i = 0; i < UCAN_MAX_RX_URBS; i++) {
void *buf;
urbs[i] = usb_alloc_urb(0, GFP_KERNEL);
if (!urbs[i])
goto err;
buf = usb_alloc_coherent(up->udev,
up->in_ep_size,
GFP_KERNEL, &urbs[i]->transfer_dma);
if (!buf) {
/* cleanup this urb */
usb_free_urb(urbs[i]);
urbs[i] = NULL;
goto err;
}
usb_fill_bulk_urb(urbs[i], up->udev,
usb_rcvbulkpipe(up->udev,
up->in_ep_addr),
buf,
up->in_ep_size,
ucan_read_bulk_callback,
up);
urbs[i]->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
usb_anchor_urb(urbs[i], &up->rx_urbs);
}
return 0;
err:
/* cleanup other unsubmitted urbs */
ucan_cleanup_rx_urbs(up, urbs);
return -ENOMEM;
}
/* Submits rx urbs with the semantic: Either submit all, or cleanup
* everything. I case of errors submitted urbs are killed and all urbs in
* the array are freed. I case of no errors every entry in the urb
* array is set to NULL.
*/
static int ucan_submit_rx_urbs(struct ucan_priv *up, struct urb **urbs)
{
int i, ret;
/* Iterate over all urbs to submit. On success remove the urb
* from the list.
*/
for (i = 0; i < UCAN_MAX_RX_URBS; i++) {
ret = usb_submit_urb(urbs[i], GFP_KERNEL);
if (ret) {
netdev_err(up->netdev,
"could not submit urb; code: %d\n",
ret);
goto err;
}
/* Anchor URB and drop reference, USB core will take
* care of freeing it
*/
usb_free_urb(urbs[i]);
urbs[i] = NULL;
}
return 0;
err:
/* Cleanup unsubmitted urbs */
ucan_cleanup_rx_urbs(up, urbs);
/* Kill urbs that are already submitted */
usb_kill_anchored_urbs(&up->rx_urbs);
return ret;
}
/* Open the network device */
static int ucan_open(struct net_device *netdev)
{
int ret, ret_cleanup;
u16 ctrlmode;
struct urb *urbs[UCAN_MAX_RX_URBS];
struct ucan_priv *up = netdev_priv(netdev);
ret = ucan_alloc_context_array(up);
if (ret)
return ret;
/* Allocate and prepare IN URBS - allocated and anchored
* urbs are stored in urbs[] for clean
*/
ret = ucan_prepare_and_anchor_rx_urbs(up, urbs);
if (ret)
goto err_contexts;
/* Check the control mode */
ctrlmode = 0;
if (up->can.ctrlmode & CAN_CTRLMODE_LOOPBACK)
ctrlmode |= UCAN_MODE_LOOPBACK;
if (up->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
ctrlmode |= UCAN_MODE_SILENT;
if (up->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
ctrlmode |= UCAN_MODE_3_SAMPLES;
if (up->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
ctrlmode |= UCAN_MODE_ONE_SHOT;
/* Enable this in any case - filtering is down within the
* receive path
*/
ctrlmode |= UCAN_MODE_BERR_REPORT;
up->ctl_msg_buffer->cmd_start.mode = cpu_to_le16(ctrlmode);
/* Driver is ready to receive data - start the USB device */
ret = ucan_ctrl_command_out(up, UCAN_COMMAND_START, 0, 2);
if (ret < 0) {
netdev_err(up->netdev,
"could not start device, code: %d\n",
ret);
goto err_reset;
}
/* Call CAN layer open */
ret = open_candev(netdev);
if (ret)
goto err_stop;
/* Driver is ready to receive data. Submit RX URBS */
ret = ucan_submit_rx_urbs(up, urbs);
if (ret)
goto err_stop;
up->can.state = CAN_STATE_ERROR_ACTIVE;
/* Start the network queue */
netif_start_queue(netdev);
return 0;
err_stop:
/* The device have started already stop it */
ret_cleanup = ucan_ctrl_command_out(up, UCAN_COMMAND_STOP, 0, 0);
if (ret_cleanup < 0)
netdev_err(up->netdev,
"could not stop device, code: %d\n",
ret_cleanup);
err_reset:
/* The device might have received data, reset it for
* consistent state
*/
ret_cleanup = ucan_ctrl_command_out(up, UCAN_COMMAND_RESET, 0, 0);
if (ret_cleanup < 0)
netdev_err(up->netdev,
"could not reset device, code: %d\n",
ret_cleanup);
/* clean up unsubmitted urbs */
ucan_cleanup_rx_urbs(up, urbs);
err_contexts:
ucan_release_context_array(up);
return ret;
}
static struct urb *ucan_prepare_tx_urb(struct ucan_priv *up,
struct ucan_urb_context *context,
struct can_frame *cf,
u8 echo_index)
{
int mlen;
struct urb *urb;
struct ucan_message_out *m;
/* create a URB, and a buffer for it, and copy the data to the URB */
urb = usb_alloc_urb(0, GFP_ATOMIC);
if (!urb) {
netdev_err(up->netdev, "no memory left for URBs\n");
return NULL;
}
m = usb_alloc_coherent(up->udev,
sizeof(struct ucan_message_out),
GFP_ATOMIC,
&urb->transfer_dma);
if (!m) {
netdev_err(up->netdev, "no memory left for USB buffer\n");
usb_free_urb(urb);
return NULL;
}
/* build the USB message */
m->type = UCAN_OUT_TX;
m->msg.can_msg.id = cpu_to_le32(cf->can_id);
if (cf->can_id & CAN_RTR_FLAG) {
mlen = UCAN_OUT_HDR_SIZE +
offsetof(struct ucan_can_msg, dlc) +
sizeof(m->msg.can_msg.dlc);
m->msg.can_msg.dlc = cf->len;
} else {
mlen = UCAN_OUT_HDR_SIZE +
sizeof(m->msg.can_msg.id) + cf->len;
memcpy(m->msg.can_msg.data, cf->data, cf->len);
}
m->len = cpu_to_le16(mlen);
m->subtype = echo_index;
/* build the urb */
usb_fill_bulk_urb(urb, up->udev,
usb_sndbulkpipe(up->udev,
up->out_ep_addr),
m, mlen, ucan_write_bulk_callback, context);
urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
return urb;
}
static void ucan_clean_up_tx_urb(struct ucan_priv *up, struct urb *urb)
{
usb_free_coherent(up->udev, sizeof(struct ucan_message_out),
urb->transfer_buffer, urb->transfer_dma);
usb_free_urb(urb);
}
/* callback when Linux needs to send a can frame */
static netdev_tx_t ucan_start_xmit(struct sk_buff *skb,
struct net_device *netdev)
{
unsigned long flags;
int ret;
u8 echo_index;
struct urb *urb;
struct ucan_urb_context *context;
struct ucan_priv *up = netdev_priv(netdev);
struct can_frame *cf = (struct can_frame *)skb->data;
/* check skb */
if (can_dev_dropped_skb(netdev, skb))
return NETDEV_TX_OK;
/* allocate a context and slow down tx path, if fifo state is low */
context = ucan_alloc_context(up);
echo_index = context - up->context_array;
if (WARN_ON_ONCE(!context))
return NETDEV_TX_BUSY;
/* prepare urb for transmission */
urb = ucan_prepare_tx_urb(up, context, cf, echo_index);
if (!urb)
goto drop;
/* put the skb on can loopback stack */
spin_lock_irqsave(&up->echo_skb_lock, flags);
can_put_echo_skb(skb, up->netdev, echo_index, 0);
spin_unlock_irqrestore(&up->echo_skb_lock, flags);
/* transmit it */
usb_anchor_urb(urb, &up->tx_urbs);
ret = usb_submit_urb(urb, GFP_ATOMIC);
/* cleanup urb */
if (ret) {
/* on error, clean up */
usb_unanchor_urb(urb);
ucan_clean_up_tx_urb(up, urb);
if (!ucan_release_context(up, context))
netdev_err(up->netdev,
"xmit err: failed to release context\n");
/* remove the skb from the echo stack - this also
* frees the skb
*/
spin_lock_irqsave(&up->echo_skb_lock, flags);
can_free_echo_skb(up->netdev, echo_index, NULL);
spin_unlock_irqrestore(&up->echo_skb_lock, flags);
if (ret == -ENODEV) {
netif_device_detach(up->netdev);
} else {
netdev_warn(up->netdev,
"xmit err: failed to submit urb %d\n",
ret);
up->netdev->stats.tx_dropped++;
}
return NETDEV_TX_OK;
}
netif_trans_update(netdev);
/* release ref, as we do not need the urb anymore */
usb_free_urb(urb);
return NETDEV_TX_OK;
drop:
if (!ucan_release_context(up, context))
netdev_err(up->netdev,
"xmit drop: failed to release context\n");
dev_kfree_skb(skb);
up->netdev->stats.tx_dropped++;
return NETDEV_TX_OK;
}
/* Device goes down
*
* Clean up used resources
*/
static int ucan_close(struct net_device *netdev)
{
int ret;
struct ucan_priv *up = netdev_priv(netdev);
up->can.state = CAN_STATE_STOPPED;
/* stop sending data */
usb_kill_anchored_urbs(&up->tx_urbs);
/* stop receiving data */
usb_kill_anchored_urbs(&up->rx_urbs);
/* stop and reset can device */
ret = ucan_ctrl_command_out(up, UCAN_COMMAND_STOP, 0, 0);
if (ret < 0)
netdev_err(up->netdev,
"could not stop device, code: %d\n",
ret);
ret = ucan_ctrl_command_out(up, UCAN_COMMAND_RESET, 0, 0);
if (ret < 0)
netdev_err(up->netdev,
"could not reset device, code: %d\n",
ret);
netif_stop_queue(netdev);
ucan_release_context_array(up);
close_candev(up->netdev);
return 0;
}
/* CAN driver callbacks */
static const struct net_device_ops ucan_netdev_ops = {
.ndo_open = ucan_open,
.ndo_stop = ucan_close,
.ndo_start_xmit = ucan_start_xmit,
.ndo_change_mtu = can_change_mtu,
};
static const struct ethtool_ops ucan_ethtool_ops = {
.get_ts_info = ethtool_op_get_ts_info,
};
/* Request to set bittiming
*
* This function generates an USB set bittiming message and transmits
* it to the device
*/
static int ucan_set_bittiming(struct net_device *netdev)
{
int ret;
struct ucan_priv *up = netdev_priv(netdev);
struct ucan_ctl_cmd_set_bittiming *cmd_set_bittiming;
cmd_set_bittiming = &up->ctl_msg_buffer->cmd_set_bittiming;
cmd_set_bittiming->tq = cpu_to_le32(up->can.bittiming.tq);
cmd_set_bittiming->brp = cpu_to_le16(up->can.bittiming.brp);
cmd_set_bittiming->sample_point =
cpu_to_le16(up->can.bittiming.sample_point);
cmd_set_bittiming->prop_seg = up->can.bittiming.prop_seg;
cmd_set_bittiming->phase_seg1 = up->can.bittiming.phase_seg1;
cmd_set_bittiming->phase_seg2 = up->can.bittiming.phase_seg2;
cmd_set_bittiming->sjw = up->can.bittiming.sjw;
ret = ucan_ctrl_command_out(up, UCAN_COMMAND_SET_BITTIMING, 0,
sizeof(*cmd_set_bittiming));
return (ret < 0) ? ret : 0;
}
/* Restart the device to get it out of BUS-OFF state.
* Called when the user runs "ip link set can1 type can restart".
*/
static int ucan_set_mode(struct net_device *netdev, enum can_mode mode)
{
int ret;
unsigned long flags;
struct ucan_priv *up = netdev_priv(netdev);
switch (mode) {
case CAN_MODE_START:
netdev_dbg(up->netdev, "restarting device\n");
ret = ucan_ctrl_command_out(up, UCAN_COMMAND_RESTART, 0, 0);
up->can.state = CAN_STATE_ERROR_ACTIVE;
/* check if queue can be restarted,
* up->available_tx_urbs must be protected by the
* lock
*/
spin_lock_irqsave(&up->context_lock, flags);
if (up->available_tx_urbs > 0)
netif_wake_queue(up->netdev);
spin_unlock_irqrestore(&up->context_lock, flags);
return ret;
default:
return -EOPNOTSUPP;
}
}
/* Probe the device, reset it and gather general device information */
static int ucan_probe(struct usb_interface *intf,
const struct usb_device_id *id)
{
int ret;
int i;
u32 protocol_version;
struct usb_device *udev;
struct net_device *netdev;
struct usb_host_interface *iface_desc;
struct ucan_priv *up;
struct usb_endpoint_descriptor *ep;
u16 in_ep_size;
u16 out_ep_size;
u8 in_ep_addr;
u8 out_ep_addr;
union ucan_ctl_payload *ctl_msg_buffer;
char firmware_str[sizeof(union ucan_ctl_payload) + 1];
udev = interface_to_usbdev(intf);
/* Stage 1 - Interface Parsing
* ---------------------------
*
* Identifie the device USB interface descriptor and its
* endpoints. Probing is aborted on errors.
*/
/* check if the interface is sane */
iface_desc = intf->cur_altsetting;
if (!iface_desc)
return -ENODEV;
dev_info(&udev->dev,
"%s: probing device on interface #%d\n",
UCAN_DRIVER_NAME,
iface_desc->desc.bInterfaceNumber);
/* interface sanity check */
if (iface_desc->desc.bNumEndpoints != 2) {
dev_err(&udev->dev,
"%s: invalid EP count (%d)",
UCAN_DRIVER_NAME, iface_desc->desc.bNumEndpoints);
goto err_firmware_needs_update;
}
/* check interface endpoints */
in_ep_addr = 0;
out_ep_addr = 0;
in_ep_size = 0;
out_ep_size = 0;
for (i = 0; i < iface_desc->desc.bNumEndpoints; i++) {
ep = &iface_desc->endpoint[i].desc;
if (((ep->bEndpointAddress & USB_ENDPOINT_DIR_MASK) != 0) &&
((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
USB_ENDPOINT_XFER_BULK)) {
/* In Endpoint */
in_ep_addr = ep->bEndpointAddress;
in_ep_addr &= USB_ENDPOINT_NUMBER_MASK;
in_ep_size = le16_to_cpu(ep->wMaxPacketSize);
} else if (((ep->bEndpointAddress & USB_ENDPOINT_DIR_MASK) ==
0) &&
((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK) ==
USB_ENDPOINT_XFER_BULK)) {
/* Out Endpoint */
out_ep_addr = ep->bEndpointAddress;
out_ep_addr &= USB_ENDPOINT_NUMBER_MASK;
out_ep_size = le16_to_cpu(ep->wMaxPacketSize);
}
}
/* check if interface is sane */
if (!in_ep_addr || !out_ep_addr) {
dev_err(&udev->dev, "%s: invalid endpoint configuration\n",
UCAN_DRIVER_NAME);
goto err_firmware_needs_update;
}
if (in_ep_size < sizeof(struct ucan_message_in)) {
dev_err(&udev->dev, "%s: invalid in_ep MaxPacketSize\n",
UCAN_DRIVER_NAME);
goto err_firmware_needs_update;
}
if (out_ep_size < sizeof(struct ucan_message_out)) {
dev_err(&udev->dev, "%s: invalid out_ep MaxPacketSize\n",
UCAN_DRIVER_NAME);
goto err_firmware_needs_update;
}
/* Stage 2 - Device Identification
* -------------------------------
*
* The device interface seems to be a ucan device. Do further
* compatibility checks. On error probing is aborted, on
* success this stage leaves the ctl_msg_buffer with the
* reported contents of a GET_INFO command (supported
* bittimings, tx_fifo depth). This information is used in
* Stage 3 for the final driver initialisation.
*/
/* Prepare Memory for control transfers */
ctl_msg_buffer = devm_kzalloc(&udev->dev,
sizeof(union ucan_ctl_payload),
GFP_KERNEL);
if (!ctl_msg_buffer) {
dev_err(&udev->dev,
"%s: failed to allocate control pipe memory\n",
UCAN_DRIVER_NAME);
return -ENOMEM;
}
/* get protocol version
*
* note: ucan_ctrl_command_* wrappers cannot be used yet
* because `up` is initialised in Stage 3
*/
ret = usb_control_msg(udev,
usb_rcvctrlpipe(udev, 0),
UCAN_COMMAND_GET,
USB_DIR_IN | USB_TYPE_VENDOR |
USB_RECIP_INTERFACE,
UCAN_COMMAND_GET_PROTOCOL_VERSION,
iface_desc->desc.bInterfaceNumber,
ctl_msg_buffer,
sizeof(union ucan_ctl_payload),
UCAN_USB_CTL_PIPE_TIMEOUT);
/* older firmware version do not support this command - those
* are not supported by this drive
*/
if (ret != 4) {
dev_err(&udev->dev,
"%s: could not read protocol version, ret=%d\n",
UCAN_DRIVER_NAME, ret);
if (ret >= 0)
ret = -EINVAL;
goto err_firmware_needs_update;
}
/* this driver currently supports protocol version 3 only */
protocol_version =
le32_to_cpu(ctl_msg_buffer->cmd_get_protocol_version.version);
if (protocol_version < UCAN_PROTOCOL_VERSION_MIN ||
protocol_version > UCAN_PROTOCOL_VERSION_MAX) {
dev_err(&udev->dev,
"%s: device protocol version %d is not supported\n",
UCAN_DRIVER_NAME, protocol_version);
goto err_firmware_needs_update;
}
/* request the device information and store it in ctl_msg_buffer
*
* note: ucan_ctrl_command_* wrappers cannot be used yet
* because `up` is initialised in Stage 3
*/
ret = usb_control_msg(udev,
usb_rcvctrlpipe(udev, 0),
UCAN_COMMAND_GET,
USB_DIR_IN | USB_TYPE_VENDOR |
USB_RECIP_INTERFACE,
UCAN_COMMAND_GET_INFO,
iface_desc->desc.bInterfaceNumber,
ctl_msg_buffer,
sizeof(ctl_msg_buffer->cmd_get_device_info),
UCAN_USB_CTL_PIPE_TIMEOUT);
if (ret < 0) {
dev_err(&udev->dev, "%s: failed to retrieve device info\n",
UCAN_DRIVER_NAME);
goto err_firmware_needs_update;
}
if (ret < sizeof(ctl_msg_buffer->cmd_get_device_info)) {
dev_err(&udev->dev, "%s: device reported invalid device info\n",
UCAN_DRIVER_NAME);
goto err_firmware_needs_update;
}
if (ctl_msg_buffer->cmd_get_device_info.tx_fifo == 0) {
dev_err(&udev->dev,
"%s: device reported invalid tx-fifo size\n",
UCAN_DRIVER_NAME);
goto err_firmware_needs_update;
}
/* Stage 3 - Driver Initialisation
* -------------------------------
*
* Register device to Linux, prepare private structures and
* reset the device.
*/
/* allocate driver resources */
netdev = alloc_candev(sizeof(struct ucan_priv),
ctl_msg_buffer->cmd_get_device_info.tx_fifo);
if (!netdev) {
dev_err(&udev->dev,
"%s: cannot allocate candev\n", UCAN_DRIVER_NAME);
return -ENOMEM;
}
up = netdev_priv(netdev);
/* initialize data */
up->udev = udev;
up->netdev = netdev;
up->intf_index = iface_desc->desc.bInterfaceNumber;
up->in_ep_addr = in_ep_addr;
up->out_ep_addr = out_ep_addr;
up->in_ep_size = in_ep_size;
up->ctl_msg_buffer = ctl_msg_buffer;
up->context_array = NULL;
up->available_tx_urbs = 0;
up->can.state = CAN_STATE_STOPPED;
up->can.bittiming_const = &up->device_info.bittiming_const;
up->can.do_set_bittiming = ucan_set_bittiming;
up->can.do_set_mode = &ucan_set_mode;
spin_lock_init(&up->context_lock);
spin_lock_init(&up->echo_skb_lock);
netdev->netdev_ops = &ucan_netdev_ops;
netdev->ethtool_ops = &ucan_ethtool_ops;
usb_set_intfdata(intf, up);
SET_NETDEV_DEV(netdev, &intf->dev);
/* parse device information
* the data retrieved in Stage 2 is still available in
* up->ctl_msg_buffer
*/
ucan_parse_device_info(up, &ctl_msg_buffer->cmd_get_device_info);
/* just print some device information - if available */
ret = ucan_device_request_in(up, UCAN_DEVICE_GET_FW_STRING, 0,
sizeof(union ucan_ctl_payload));
if (ret > 0) {
/* copy string while ensuring zero termination */
strscpy(firmware_str, up->ctl_msg_buffer->raw,
sizeof(union ucan_ctl_payload) + 1);
} else {
strcpy(firmware_str, "unknown");
}
/* device is compatible, reset it */
ret = ucan_ctrl_command_out(up, UCAN_COMMAND_RESET, 0, 0);
if (ret < 0)
goto err_free_candev;
init_usb_anchor(&up->rx_urbs);
init_usb_anchor(&up->tx_urbs);
up->can.state = CAN_STATE_STOPPED;
/* register the device */
ret = register_candev(netdev);
if (ret)
goto err_free_candev;
/* initialisation complete, log device info */
netdev_info(up->netdev, "registered device\n");
netdev_info(up->netdev, "firmware string: %s\n", firmware_str);
/* success */
return 0;
err_free_candev:
free_candev(netdev);
return ret;
err_firmware_needs_update:
dev_err(&udev->dev,
"%s: probe failed; try to update the device firmware\n",
UCAN_DRIVER_NAME);
return -ENODEV;
}
/* disconnect the device */
static void ucan_disconnect(struct usb_interface *intf)
{
struct ucan_priv *up = usb_get_intfdata(intf);
usb_set_intfdata(intf, NULL);
if (up) {
unregister_candev(up->netdev);
free_candev(up->netdev);
}
}
static struct usb_device_id ucan_table[] = {
/* Mule (soldered onto compute modules) */
{USB_DEVICE_INTERFACE_NUMBER(0x2294, 0x425a, 0)},
/* Seal (standalone USB stick) */
{USB_DEVICE_INTERFACE_NUMBER(0x2294, 0x425b, 0)},
{} /* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, ucan_table);
/* driver callbacks */
static struct usb_driver ucan_driver = {
.name = UCAN_DRIVER_NAME,
.probe = ucan_probe,
.disconnect = ucan_disconnect,
.id_table = ucan_table,
};
module_usb_driver(ucan_driver);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Martin Elshuber <martin.elshuber@theobroma-systems.com>");
MODULE_AUTHOR("Jakob Unterwurzacher <jakob.unterwurzacher@theobroma-systems.com>");
MODULE_DESCRIPTION("Driver for Theobroma Systems UCAN devices");