Re: [PATCH 2/2] ems_usb: Added support for EMS CPC-USB/ARM7 CAN/USB interface

[Sebastian Haas <haas@ems-wuensche.com>]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Wolfgang Grandegger schrieb:
> Hi Sebastian,
> 
> Sebastian Haas wrote:
>> This patch adds support for one channel CAN/USB interace CPC-USB/ARM7 from
>> EMS Dr. Thomas Wuensche (http://www.ems-wuensche.com).
>>
>> Signed-off-by: Sebastian Haas <haas@ems-wuensche.com>
> 
> The driver is almost OK from the Socket-CAN point of view. Just some
> *final* nitpicking:
> 
> [snip]
>> +static void ems_usb_read_interrupt_callback(struct urb *urb)
>> +{
>> +	struct ems_usb *dev = urb->context;
>> +	struct net_device *netdev;
>> +	int err;
>> +
>> +	netdev = dev->netdev;
> 
> Could be done in the declaration part above.
Fixed.

>> +	if (!netif_device_present(netdev))
>> +		return;
>> +
>> +	switch (urb->status) {
>> +	case 0:
>> +		dev->free_slots = dev->intr_in_buffer[1];
>> +		break;
>> +
>> +	case -ECONNRESET: /* unlink */
>> +	case -ENOENT:
>> +	case -ESHUTDOWN:
>> +		return;
>> +
>> +	default:
>> +		dev_info(netdev->dev.parent, "Rx interrupt aborted %d\n",
>> +			 urb->status);
>> +		break;
>> +	}
>> +
>> +	err = usb_submit_urb(urb, GFP_ATOMIC);
>> +
>> +	if (err == -ENODEV)
>> +		netif_device_detach(netdev);
>> +	else if (err)
>> +		dev_err(netdev->dev.parent,
>> +			"failed resubmitting intr urb: %d\n", err);
>> +
>> +	return;
>> +}
>> +
>> +static void ems_usb_rx_can_msg(struct ems_usb *dev, struct ems_cpc_msg *msg)
>> +{
>> +	struct can_frame *cf;
>> +	struct sk_buff *skb;
>> +	int i;
>> +	struct net_device_stats *stats = &dev->netdev->stats;
>> +
>> +	skb = dev_alloc_skb(sizeof(struct can_frame));
> 
> Please use netdev_alloc_skb() ...
Fixed.

>> +	if (skb == NULL)
>> +		return;
>> +
>> +	skb->dev = dev->netdev;
> 
> ... making the line above obsolete.
Fixed.

>> +	skb->protocol = htons(ETH_P_CAN);
>> +
>> +	cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
>> +
>> +	cf->can_id = msg->msg.can_msg.id;
>> +	cf->can_dlc = min_t(u8, msg->msg.can_msg.length, 8);
>> +
>> +	if (msg->type == CPC_MSG_TYPE_EXT_CAN_FRAME
>> +	    || msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME)
>> +		cf->can_id |= CAN_EFF_FLAG;
>> +
>> +	if (msg->type == CPC_MSG_TYPE_RTR_FRAME
>> +	    || msg->type == CPC_MSG_TYPE_EXT_RTR_FRAME) {
>> +		cf->can_id |= CAN_RTR_FLAG;
>> +	} else {
>> +		for (i = 0; i < cf->can_dlc; i++)
>> +			cf->data[i] = msg->msg.can_msg.msg[i];
>> +	}
>> +
>> +	netif_rx(skb);
>> +
>> +	dev->netdev->last_rx = jiffies;
>> +	stats->rx_packets++;
>> +	stats->rx_bytes += cf->can_dlc;
>> +}
>> +
>> +static void ems_usb_rx_err(struct ems_usb *dev, struct ems_cpc_msg *msg)
>> +{
>> +	struct can_frame *cf;
>> +	struct sk_buff *skb;
>> +	struct net_device_stats *stats = &dev->netdev->stats;
>> +
>> +	skb = dev_alloc_skb(sizeof(struct can_frame));
>> +	if (skb == NULL)
>> +		return;
>> +
>> +	skb->dev = dev->netdev;
> 
> Ditto.
> 
> [snip]
>> +static int ems_usb_start_xmit(struct sk_buff *skb, struct net_device *netdev)
>> +{
>> +	struct ems_usb *dev = netdev_priv(netdev);
>> +	struct ems_tx_urb_context *context = NULL;
>> +	struct net_device_stats *stats = &netdev->stats;
>> +	struct can_frame *cf = (struct can_frame *)skb->data;
>> +	struct ems_cpc_msg *msg;
>> +	struct urb *urb;
>> +	u8 *buf;
>> +	int i, err;
>> +	size_t size = CPC_HEADER_SIZE + CPC_MSG_HEADER_LEN
>> +			+ sizeof(struct cpc_can_msg);
>> +
>> +	/* create a URB, and a buffer for it, and copy the data to the URB */
>> +	urb = usb_alloc_urb(0, GFP_ATOMIC);
>> +	if (!urb) {
>> +		dev_err(netdev->dev.parent, "No memory left for URBs\n");
>> +		goto nomem;
>> +	}
>> +
>> +	buf = usb_buffer_alloc(dev->udev, size, GFP_ATOMIC, &urb->transfer_dma);
>> +	if (!buf) {
>> +		dev_err(netdev->dev.parent, "No memory left for USB buffer\n");
>> +		usb_free_urb(urb);
>> +		goto nomem;
>> +	}
>> +
>> +	msg = (struct ems_cpc_msg *)&buf[CPC_HEADER_SIZE];
>> +
>> +	msg->msg.can_msg.id = cf->can_id & 0x1FFFFFFFU;
> 
> Please use CAN_ERR_MASK instead (even if the name is somehow
> misleading). See http://lxr.linux.no/#linux+v2.6.31/include/linux/can.h#L31.
Fixed.

> [snip]
>> +}
>> +
>> +
> 
> Remove one empty line, please.
Fixed.

>> +static void init_params_sja1000(struct ems_cpc_msg *msg)
>> +{
>> +	struct cpc_sja1000_params *sja1000 =
>> +		&msg->msg.can_params.cc_params.sja1000;
>> +
>> +	msg->type = CPC_CMD_TYPE_CAN_PARAMS;
>> +	msg->length = sizeof(struct cpc_can_params);
>> +	msg->msgid = 0;
>> +
>> +	msg->msg.can_params.cc_type = CPC_CC_TYPE_SJA1000;
>> +
>> +	/* Acceptance filter open */
>> +	sja1000->acc_code0 = 0x00;
>> +	sja1000->acc_code1 = 0x00;
>> +	sja1000->acc_code2 = 0x00;
>> +	sja1000->acc_code3 = 0x00;
>> +
>> +	/* Acceptance filter open */
>> +	sja1000->acc_mask0 = 0xFF;
>> +	sja1000->acc_mask1 = 0xFF;
>> +	sja1000->acc_mask2 = 0xFF;
>> +	sja1000->acc_mask3 = 0xFF;
>> +
>> +	sja1000->btr0 = 0;
>> +	sja1000->btr1 = 0;
>> +
>> +	sja1000->outp_contr = SJA1000_DEFAULT_OUTPUT_CONTROL;
>> +	sja1000->mode = SJA1000_MOD_RM;
>> +}
>> +
>> +/*
>> + * probe function for new CPC-USB devices
>> + */
>> +static int ems_usb_probe(struct usb_interface *intf,
>> +			 const struct usb_device_id *id)
>> +{
>> +	struct net_device *netdev;
>> +	struct ems_usb *dev;
>> +	int i, err;
>> +
>> +	netdev = alloc_candev(sizeof(struct ems_usb));
>> +	if (!netdev) {
>> +		dev_err(netdev->dev.parent, "Couldn't alloc candev\n");
>> +		return -ENOMEM;
>> +	}
>> +
>> +	dev = netdev_priv(netdev);
>> +
>> +	dev->udev = interface_to_usbdev(intf);
>> +	dev->netdev = netdev;
>> +
>> +	dev->can.state = CAN_STATE_STOPPED;
>> +	dev->can.bittiming_const = &ems_usb_bittiming_const;
>> +	dev->can.do_set_bittiming = ems_usb_set_bittiming;
>> +	dev->can.do_set_mode = ems_usb_set_mode;
>> +
>> +	netdev->flags |= IFF_ECHO; /* we support local echo */
>> +
>> +	/*
>> +	 * The device actually uses a 16MHz clock to generate the CAN clock
>> +	 * but it expects SJA1000 bit settings based on 8MHz (is internally
>> +	 * converted).
>> +	 */
> 
> Should go up to the macro definition.
Fixed.

>> +	dev->can.clock.freq = EMS_USB_ARM7_CLOCK;
>> +
>> +	netdev->netdev_ops = &ems_usb_netdev_ops;
>> +
>> +	netdev->flags |= IFF_ECHO; /* we support local echo */
>> +
>> +	init_usb_anchor(&dev->rx_submitted);
>> +
>> +	init_usb_anchor(&dev->tx_submitted);
>> +	atomic_set(&dev->active_tx_urbs, 0);
>> +
>> +	for (i = 0; i < MAX_TX_URBS; i++)
>> +		dev->tx_contexts[i].echo_index = MAX_TX_URBS;
>> +
>> +	dev->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
>> +	if (!dev->intr_urb) {
>> +		dev_err(netdev->dev.parent, "Couldn't alloc intr URB\n");
>> +		free_candev(netdev);
> 
> Please use goto's for cleanup to avoid code duplication.
> 
>> +		return -ENOMEM;
>> +	}
>> +
>> +	dev->intr_in_buffer = kzalloc(INTR_IN_BUFFER_SIZE, GFP_KERNEL);
>> +	if (!dev->intr_in_buffer) {
>> +		dev_err(netdev->dev.parent, "Couldn't alloc Intr buffer\n");
>> +		free_candev(netdev);
>> +		usb_free_urb(dev->intr_urb);
>> +		return -ENOMEM;
> 
> Ditto.
> 
>> +	}
>> +
>> +	dev->tx_msg_buffer = kzalloc(CPC_HEADER_SIZE +
>> +				     sizeof(struct ems_cpc_msg), GFP_KERNEL);
>> +	if (!dev->tx_msg_buffer) {
>> +		dev_err(netdev->dev.parent, "Couldn't alloc Tx buffer\n");
>> +		free_candev(netdev);
>> +		usb_free_urb(dev->intr_urb);
>> +		kfree(dev->intr_in_buffer);
>> +		return -ENOMEM;
> 
> Ditto.
> 
>> +	}
>> +
>> +	usb_set_intfdata(intf, dev);
>> +
>> +	SET_NETDEV_DEV(netdev, &intf->dev);
>> +
>> +	init_params_sja1000(&dev->active_params);
>> +
>> +	err = ems_usb_command_msg(dev, &dev->active_params);
>> +	if (err) {
>> +		dev_err(netdev->dev.parent,
>> +			"couldn't initialize controller: %d\n", err);
>> +		free_candev(netdev);
>> +		usb_free_urb(dev->intr_urb);
>> +		return err;
> 
> Ditto. Also kfree(dev->intr_in_buffer) seems to be missing.
Fixed.

> Please add a version number to the next patch, e.g. [PATCH v3 ...].
Okay, have to figure out how to do with stgit ;-)

> It would also be nice, if some USB guru's could have a look as well.
Oliver Neukum already did a quick review. I've fixed serveral
GFP_ATOMIC/KERNEL issues and a problem with DMA coherency on his feedback.

Cheers, Sebastian
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iEYEARECAAYFAkqvfUAACgkQpqRB8PJG7Xxw/ACfT8FUQ5DlmrcDnxotWceIcyNn
fOIAoI/w8NHJg0qGxpF2PvU6Qd5BXaBg
=DV5x
-----END PGP SIGNATURE-----
-- 
EMS Dr. Thomas Wuensche e.K.
Sonnenhang 3
85304 Ilmmuenster
HRA Neuburg a.d. Donau, HR-Nr. 70.106
Phone: +49-8441-490260
Fax  : +49-8441-81860
http://www.ems-wuensche.com