The UCAN driver supports the microcontroller-based USB/CAN adapters from Theobroma Systems. There are two form-factors that run essentially the same firmware:
* Seal: standalone USB stick ( https://www.theobroma-systems.com/seal ) * Mule: integrated on the PCB of various System-on-Modules from Theobroma Systems like the A31-µQ7 and the RK3399-Q7 ( https://www.theobroma-systems.com/rk3399-q7 ) The USB wire protocol has been designed to be as generic and hardware-indendent as possible in the hope of being useful for implementation on other microcontrollers. Signed-off-by: Martin Elshuber <martin.elshu...@theobroma-systems.com> Signed-off-by: Jakob Unterwurzacher <jakob.unterwurzac...@theobroma-systems.com> Signed-off-by: Philipp Tomsich <philipp.toms...@theobroma-systems.com> --- Documentation/networking/can_ucan_protocol.rst | 315 +++++ Documentation/networking/index.rst | 1 + drivers/net/can/usb/Kconfig | 10 + drivers/net/can/usb/Makefile | 1 + drivers/net/can/usb/ucan.c | 1596 ++++++++++++++++++++++++ 5 files changed, 1923 insertions(+) create mode 100644 Documentation/networking/can_ucan_protocol.rst create mode 100644 drivers/net/can/usb/ucan.c diff --git a/Documentation/networking/can_ucan_protocol.rst b/Documentation/networking/can_ucan_protocol.rst new file mode 100644 index 000000000000..d859b36200b4 --- /dev/null +++ b/Documentation/networking/can_ucan_protocol.rst @@ -0,0 +1,315 @@ +================= +The UCAN Protocol +================= + +UCAN is the protocol used by the microcontroller-based USB-CAN +adapter that is integrated on System-on-Modules from Theobroma Systems +and that is also available as a standalone USB stick. + +The UCAN protocol has been designed to be hardware-independent. +It is modeled closely after how Linux represents CAN devices +internally. All multi-byte integers are encoded as Little Endian. + +All structures mentioned in this document are defined in +``drivers/net/can/usb/ucan.c``. + +USB Endpoints +============= + +UCAN devices use three USB endpoints: + +CONTROL endpoint + The driver sends device management commands on this endpoint + +IN endpoint + The device sends CAN data frames and CAN error frames + +OUT endpoint + The driver sends CAN data frames on the out endpoint + + +CONTROL Messages +================ + +UCAN devices are configured using vendor requests on the control pipe. + +To support multiple CAN interfaces in a single USB device all +configuration commands target the corresponding interface in the USB +descriptor. + +The driver uses ``ucan_ctrl_command_in/out`` and +``ucan_device_request_in`` to deliver commands to the device. + +Setup Packet +------------ + +================= ===================================================== +``bmRequestType`` Direction | Vendor | (Interface or Device) +``bRequest`` Command Number +``wValue`` Subcommand Number (16 Bit) or 0 if not used +``wIndex`` USB Interface Index (0 for device commands) +``wLength`` * Host to Device - Number of bytes to transmit + * Device to Host - Maximum Number of bytes to + receive. If the device send less. Commom ZLP + semantics are used. +================= ===================================================== + +Error Handling +-------------- + +The device indicates failed control commands by stalling the +pipe. + +Device Commands +--------------- + +UCAN_DEVICE_GET_FW_STRING +~~~~~~~~~~~~~~~~~~~~~~~~~ + +*Dev2Host; optional* + +Request the device firmware string. + + +Interface Commands +------------------ + +UCAN_COMMAND_START +~~~~~~~~~~~~~~~~~~ + +*Host2Dev; mandatory* + +Bring the CAN interface up. + +Payload Format + ``ucan_ctl_payload_t.cmd_start`` + +==== ============================ +mode or mask of ``UCAN_MODE_*`` +==== ============================ + +UCAN_COMMAND_STOP +~~~~~~~~~~~~~~~~~~ + +*Host2Dev; mandatory* + +Stop the CAN interface + +Payload Format + *empty* + +UCAN_COMMAND_RESET +~~~~~~~~~~~~~~~~~~ + +*Host2Dev; mandatory* + +Reset the CAN controller (including error counters) + +Payload Format + *empty* + +UCAN_COMMAND_GET +~~~~~~~~~~~~~~~~ + +*Host2Dev; mandatory* + +Get Information from the Device + +Subcommands +^^^^^^^^^^^ + +UCAN_COMMAND_GET_INFO + Request the device information structure ``ucan_ctl_payload_t.device_info``. + + See the ``device_info`` field for details, and + ``uapi/linux/can/netlink.h`` for an explanation of the + ``can_bittiming fields``. + + Payload Format + ``ucan_ctl_payload_t.device_info`` + +UCAN_COMMAND_GET_PROTOCOL_VERSION + + Request the device protocol version + ``ucan_ctl_payload_t.protocol_version``. The current protocol version is 3. + + Payload Format + ``ucan_ctl_payload_t.protocol_version`` + +.. note:: Devices that do not implement this command use the old + protocol version 1 + +UCAN_COMMAND_SET_BITTIMING +~~~~~~~~~~~~~~~~~~~~~~~~~~ + +*Host2Dev; mandatory* + +Setup bittiming by sending the the structure +``ucan_ctl_payload_t.cmd_set_bittiming`` (see ``struct bittiming`` for +details) + +Payload Format + ``ucan_ctl_payload_t.cmd_set_bittiming``. + +UCAN_SLEEP/WAKE +~~~~~~~~~~~~~~~ + +*Host2Dev; optional* + +Configure sleep and wake modes. Not yet supported by the driver. + +UCAN_FILTER +~~~~~~~~~~~ + +*Host2Dev; optional* + +Setup hardware CAN filters. Not yet supported by the driver. + +Allowed interface commands +-------------------------- + +================== =================== ================== +Legal Device State Command New Device State +================== =================== ================== +stopped SET_BITTIMING stopped +stopped START started +started STOP or RESET stopped +stopped STOP or RESET stopped +started RESTART started +any GET *no change* +================== =================== ================== + +IN Message Format +================= + +A data packet on the USB IN endpoint contains one or more +``ucan_message_in`` values. If multiple messages are batched in a USB +data packet, the ``len`` field can be used to jump to the next +``ucan_message_in`` value (take care to sanity-check the ``len`` value +against the actual data size). + +.. _can_ucan_in_message_len: + +``len`` field +------------- + +Each ``ucan_message_in`` must be aligned to a 4-byte boundary (relative +to the start of the start of the data buffer). That means that there +may be padding bytes between multiple ``ucan_message_in`` values: + +.. code:: + + +----------------------------+ < 0 + | | + | struct ucan_message_in | + | | + +----------------------------+ < len + [padding] + +----------------------------+ < round_up(len, 4) + | | + | struct ucan_message_in | + | | + +----------------------------+ + [...] + +``type`` field +-------------- + +The ``type`` field specifies the type of the message. + +UCAN_IN_RX +~~~~~~~~~~ + +``subtype`` + zero + +Data received from the CAN bus (ID + payload). + +UCAN_IN_TX_COMPLETE +~~~~~~~~~~~~~~~~~~~ + +``subtype`` + zero + +The CAN device has sent a message to the CAN bus. It answers with a +set of echo-ids from previous UCAN_OUT_TX messages + +Flow Control +------------ + +When receiving CAN messages there is no flow control on the USB +buffer. The driver has to handle inbound message quickly enough to +avoid drops. I case the device buffer overflow the condition is +reported by sending corresponding error frames (see +:ref:`can_ucan_error_handling`) + + +OUT Message Format +================== + +A data packet on the USB OUT endpoint contains one or more ``struct +ucan_message_out`` values. If multiple messages are batched into one +data packet, the device uses the ``len`` field to jump to the next +ucan_message_out value. Each ucan_message_out must be aligned to 4 +bytes (relative to the start of the data buffer). The mechanism is +same as described in :ref:`can_ucan_in_message_len`. + +.. code:: + + +----------------------------+ < 0 + | | + | struct ucan_message_out | + | | + +----------------------------+ < len + [padding] + +----------------------------+ < round_up(len, 4) + | | + | struct ucan_message_out | + | | + +----------------------------+ + [...] + +``type`` field +-------------- + +In protocol version 3 only ``UCAN_OUT_TX`` is defined, others are used +only by legacy devices (protocol version 1). + +UCAN_OUT_TX +~~~~~~~~~~~ +``subtype`` + echo id to be replied within a CAN_IN_TX_COMPLETE message + +Transmit a CAN frame. (parameters: ``id``, ``data``) + +Flow Control +------------ + +When the device outbound buffers are full it starts sending *NAKs* on +the *OUT* pipe until more buffers are available. The driver stops the +queue when a certain threshold of out packets are incomplete. + +.. _can_ucan_error_handling: + +CAN Error Handling +================== + +If error reporting is turned on the device encodes errors into CAN +error frames (see ``uapi/linux/can/error.h``) and sends it using the +IN endpoint. The driver updates its error statistics and forwards +it. + +Although UCAN devices can suppress error frames completely, in Linux +the driver is always interested. Hence, the device is always started with +the ``UCAN_MODE_BERR_REPORT`` set. Filtering those messages for the +user space is done by the driver. + +Example Conversation +==================== + +#) Device is connected to USB +#) Host sends command ``UCAN_COMMAND_RESET``, subcmd 0 +#) Host sends command ``UCAN_COMMAND_GET``, subcmd ``UCAN_COMMAND_GET_INFO`` +#) Device sends ``UCAN_IN_DEVICE_INFO`` +#) Host sends command ``UCAN_OUT_SET_BITTIMING`` +#) Host sends command ``UCAN_COMMAND_START``, subcmd 0, mode ``UCAN_MODE_BERR_REPORT`` diff --git a/Documentation/networking/index.rst b/Documentation/networking/index.rst index 90966c2692d8..18903968cebf 100644 --- a/Documentation/networking/index.rst +++ b/Documentation/networking/index.rst @@ -8,6 +8,7 @@ Contents: batman-adv can + can_ucan_protocol kapi z8530book msg_zerocopy diff --git a/drivers/net/can/usb/Kconfig b/drivers/net/can/usb/Kconfig index c36f4bdcbf4f..490cdce1f1da 100644 --- a/drivers/net/can/usb/Kconfig +++ b/drivers/net/can/usb/Kconfig @@ -89,4 +89,14 @@ config CAN_MCBA_USB This driver supports the CAN BUS Analyzer interface from Microchip (http://www.microchip.com/development-tools/). +config CAN_UCAN + tristate "Theobroma Systems UCAN interface" + ---help--- + This driver supports the Theobroma Systems + UCAN USB-CAN interface. + + UCAN is an microcontroller-based USB-CAN interface that + is integrated on System-on-Modules made by Theobroma Systems + (https://www.theobroma-systems.com/som-products). + endmenu diff --git a/drivers/net/can/usb/Makefile b/drivers/net/can/usb/Makefile index 49ac7b99ba32..4176e8358232 100644 --- a/drivers/net/can/usb/Makefile +++ b/drivers/net/can/usb/Makefile @@ -10,3 +10,4 @@ obj-$(CONFIG_CAN_KVASER_USB) += kvaser_usb.o obj-$(CONFIG_CAN_PEAK_USB) += peak_usb/ obj-$(CONFIG_CAN_8DEV_USB) += usb_8dev.o obj-$(CONFIG_CAN_MCBA_USB) += mcba_usb.o +obj-$(CONFIG_CAN_UCAN) += ucan.o diff --git a/drivers/net/can/usb/ucan.c b/drivers/net/can/usb/ucan.c new file mode 100644 index 000000000000..bb2d62dcbd7b --- /dev/null +++ b/drivers/net/can/usb/ucan.c @@ -0,0 +1,1596 @@ +// 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/module.h> +#include <linux/netdevice.h> +#include <linux/signal.h> +#include <linux/skbuff.h> +#include <linux/slab.h> +#include <linux/usb.h> + +#include <linux/can.h> +#include <linux/can/dev.h> +#include <linux/can/error.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) + */ + struct ucan_tx_complete_entry_t can_tx_complete_msg[0]; + } __aligned(0x4) msg; +} __packed; + +/* 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; + u8 dlc; + 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 usb_interface *intf; + struct net_device *netdev; + + /* 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_get_can_dlc(struct ucan_can_msg *msg, u16 len) +{ + if (le32_to_cpu(msg->id) & CAN_RTR_FLAG) + return get_can_dlc(msg->dlc); + else + return get_can_dlc(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); + + goto done_restore; + } + } + +done_restore: + 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) + goto done_restore; + 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++; + +done_restore: + 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 *ctl_cmd_device_info) +{ + struct can_bittiming_const *bittiming = + &up->device_info.bittiming_const; + u16 ctrlmodes; + + /* store the data */ + up->can.clock.freq = le32_to_cpu(ctl_cmd_device_info->freq); + up->device_info.tx_fifo = ctl_cmd_device_info->tx_fifo; + strcpy(bittiming->name, "ucan"); + bittiming->tseg1_min = ctl_cmd_device_info->tseg1_min; + bittiming->tseg1_max = ctl_cmd_device_info->tseg1_max; + bittiming->tseg2_min = ctl_cmd_device_info->tseg2_min; + bittiming->tseg2_max = ctl_cmd_device_info->tseg2_max; + bittiming->sjw_max = ctl_cmd_device_info->sjw_max; + bittiming->brp_min = le32_to_cpu(ctl_cmd_device_info->brp_min); + bittiming->brp_max = le32_to_cpu(ctl_cmd_device_info->brp_max); + bittiming->brp_inc = le16_to_cpu(ctl_cmd_device_info->brp_inc); + + ctrlmodes = le16_to_cpu(ctl_cmd_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); + netdev_info(up->netdev, "link has gone into BUS-OFF state\n"); + 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, + "masking unexpected set bits in canid (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->can_dlc = ucan_get_can_dlc(&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->can_dlc); + + /* don't count error frames as real packets */ + stats->rx_packets++; + stats->rx_bytes += cf->can_dlc; + + /* 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) +{ + u16 count, i; + u8 echo_index, dlc; + 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, + "device answered with invalid echo_index %d\n", + echo_index); + continue; + } + + /* gather information from the context */ + context = &up->context_array[echo_index]; + dlc = READ_ONCE(context->dlc); + + /* Release context and restart queue if necessary. + * Also check if the context was allocated + */ + if (ucan_release_context(up, context)) + continue; + + 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 += dlc; + can_get_echo_skb(up->netdev, echo_index); + } else { + up->netdev->stats.tx_dropped++; + can_free_echo_skb(up->netdev, echo_index); + } + } +} + +/* 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 resumbmitting 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 input message %d; too short (no header)\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 input message al:%d pos:%d len:%d; too short (no data)\n", + urb->actual_length, pos, len); + 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 input message type\n"); + 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_KERNEL); + + 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) +{ + struct ucan_urb_context *context = urb->context; + struct ucan_priv *up; + + /* 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 */ + can_free_echo_skb(up->netdev, context - up->context_array); + + 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) + goto err; + + /* 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); + +err: + 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->can_dlc; + } else { + mlen = UCAN_OUT_HDR_SIZE + + sizeof(m->msg.can_msg.id) + cf->can_dlc; + memcpy(m->msg.can_msg.data, cf->data, cf->can_dlc); + } + m->len = cpu_to_le16(mlen); + + context->dlc = cf->can_dlc; + + 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) +{ + 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_dropped_invalid_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 */ + can_put_echo_skb(skb, up->netdev, echo_index); + + /* 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 submit err: failed to release context\n"); + + /* remove the skb from the echo stack - this also + * frees the skb + */ + can_free_echo_skb(up->netdev, echo_index); + + if (ret == -ENODEV) { + netif_device_detach(up->netdev); + } else { + netdev_warn(up->netdev, + "failed to transmit tx_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, +}; + +/* 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 */ + ret = -ENODEV; + iface_desc = intf->cur_altsetting; + if (!iface_desc) + goto err; + + 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: incompatible (possibly old) interface. It must have 2 endpoints but has %d\n", + UCAN_DRIVER_NAME, iface_desc->desc.bNumEndpoints); + goto err; + } + + /* 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; + } + if (in_ep_size < sizeof(struct ucan_message_in)) { + dev_err(&udev->dev, "%s: invalid in_ep MaxPacketSize\n", + UCAN_DRIVER_NAME); + goto err; + } + if (out_ep_size < sizeof(struct ucan_message_out)) { + dev_err(&udev->dev, "%s: invalid out_ep MaxPacketSize\n", + UCAN_DRIVER_NAME); + goto err; + } + + /* 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 transferes */ + 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 memory for controls transfers\n", + UCAN_DRIVER_NAME); + goto err; + } + + /* 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. The firmware on this device is too old, please update!\n", + UCAN_DRIVER_NAME, ret); + if (ret >= 0) + ret = -EINVAL; + goto err; + } + + /* 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); + ret = -EINVAL; + goto err; + } + + /* request the device information and store it in ctl_msg_buffer + * + * note: ucan_ctrl_command_* wrappers connot 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; + } + if (ret < sizeof(ctl_msg_buffer->cmd_get_device_info)) { + dev_err(&udev->dev, "%s: device reported invalid device info\n", + UCAN_DRIVER_NAME); + ret = -EINVAL; + goto err; + } + 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); + ret = -EINVAL; + goto err; + } + + /* 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); + ret = -ENOMEM; + goto err; + } + + up = netdev_priv(netdev); + + /* initialze data */ + up->udev = udev; + up->intf = intf; + 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); + netdev->netdev_ops = &ucan_netdev_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 terminiation */ + strncpy(firmware_str, up->ctl_msg_buffer->raw, + sizeof(union ucan_ctl_payload)); + firmware_str[sizeof(union ucan_ctl_payload)] = '\0'; + } 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); +err: + return ret; +} + +/* disconnect the device */ +static void ucan_disconnect(struct usb_interface *intf) +{ + struct usb_device *udev; + struct ucan_priv *up = usb_get_intfdata(intf); + + udev = interface_to_usbdev(intf); + + usb_set_intfdata(intf, NULL); + + if (up) { + unregister_netdev(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.elshu...@theobroma-systems.com>"); +MODULE_AUTHOR("Jakob Unterwurzacher <jakob.unterwurzac...@theobroma-systems.com>"); +MODULE_DESCRIPTION("Driver for Theobroma Systems UCAN devices"); -- 2.11.0
