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Commit 404814af authored by Bjørn Mork's avatar Bjørn Mork Committed by David S. Miller
Browse files

net: cdc_ncm: add "ndp_to_end" sysfs attribute 



Adding a writable sysfs attribute for the "NDP to end"
quirk flag.

This makes it easier for end users to test new devices for
this firmware bug.  We've been lucky so far, but we should
not depend on reporters capable of rebuilding the driver.

Cc: Enrico Mioso <mrkiko.rs@gmail.com>
Signed-off-by: default avatarBjørn Mork <bjorn@mork.no>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0fe3e204

Documentation/ABI/testing/sysfs-class-net-cdc_ncm

+19 −0
Original line number Diff line number Diff line
@@ -19,6 +19,25 @@ Description: 
		Set to 0 to pad all frames. Set greater than tx_max to

		disable all padding.



What:		/sys/class/net/<iface>/cdc_ncm/ndp_to_end

Date:		Dec 2015

KernelVersion:	4.5

Contact:	Bjørn Mork <bjorn@mork.no>

Description:

		Boolean attribute showing the status of the "NDP to

		end" quirk.  Defaults to 'N', except for devices

		already known to need it enabled.



		The "NDP to end" quirk makes the driver place the NDP

		(the packet index table) after the payload.  The NCM

		specification does not mandate this, but some devices

		are known to be more restrictive. Write 'Y' to this

		attribute for temporary testing of a suspect device

		failing to work with the default driver settings.



		A device entry should be added to the driver if this

		quirk is found to be required.



What:		/sys/class/net/<iface>/cdc_ncm/rx_max

Date:		May 2014

KernelVersion:	3.16

drivers/net/usb/cdc_ncm.c

+43 −0
Original line number Diff line number Diff line
@@ -283,6 +283,48 @@ static DEVICE_ATTR(rx_max, S_IRUGO | S_IWUSR, cdc_ncm_show_rx_max, cdc_ncm_store 
static DEVICE_ATTR(tx_max, S_IRUGO | S_IWUSR, cdc_ncm_show_tx_max, cdc_ncm_store_tx_max);

static DEVICE_ATTR(tx_timer_usecs, S_IRUGO | S_IWUSR, cdc_ncm_show_tx_timer_usecs, cdc_ncm_store_tx_timer_usecs);



static ssize_t ndp_to_end_show(struct device *d, struct device_attribute *attr, char *buf)

{

	struct usbnet *dev = netdev_priv(to_net_dev(d));

	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];



	return sprintf(buf, "%c\n", ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END ? 'Y' : 'N');

}



static ssize_t ndp_to_end_store(struct device *d,  struct device_attribute *attr, const char *buf, size_t len)

{

	struct usbnet *dev = netdev_priv(to_net_dev(d));

	struct cdc_ncm_ctx *ctx = (struct cdc_ncm_ctx *)dev->data[0];

	bool enable;



	if (strtobool(buf, &enable))

		return -EINVAL;



	/* no change? */

	if (enable == (ctx->drvflags & CDC_NCM_FLAG_NDP_TO_END))

		return len;



	if (enable && !ctx->delayed_ndp16) {

		ctx->delayed_ndp16 = kzalloc(ctx->max_ndp_size, GFP_KERNEL);

		if (!ctx->delayed_ndp16)

			return -ENOMEM;

	}



	/* flush pending data before changing flag */

	netif_tx_lock_bh(dev->net);

	usbnet_start_xmit(NULL, dev->net);

	spin_lock_bh(&ctx->mtx);

	if (enable)

		ctx->drvflags |= CDC_NCM_FLAG_NDP_TO_END;

	else

		ctx->drvflags &= ~CDC_NCM_FLAG_NDP_TO_END;

	spin_unlock_bh(&ctx->mtx);

	netif_tx_unlock_bh(dev->net);



	return len;

}

static DEVICE_ATTR_RW(ndp_to_end);



#define NCM_PARM_ATTR(name, format, tocpu)				\

static ssize_t cdc_ncm_show_##name(struct device *d, struct device_attribute *attr, char *buf) \

{ \
@@ -305,6 +347,7 @@ NCM_PARM_ATTR(wNtbOutMaxDatagrams, "%u", le16_to_cpu); 


static struct attribute *cdc_ncm_sysfs_attrs[] = {

	&dev_attr_min_tx_pkt.attr,

	&dev_attr_ndp_to_end.attr,

	&dev_attr_rx_max.attr,

	&dev_attr_tx_max.attr,

	&dev_attr_tx_timer_usecs.attr,