From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?q?Bj=C3=B8rn=20Mork?= Subject: [PATCH v2 net-next 7/8] net: cdc_ncm: allow tuning min_tx_pkt Date: Fri, 30 May 2014 09:31:09 +0200 Message-ID: <1401435070-26721-8-git-send-email-bjorn@mork.no> References: <1401435070-26721-1-git-send-email-bjorn@mork.no> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: , Alexey Orishko , Oliver Neukum , Enrico Mioso , David Laight , Lars Melin , Peter Stuge , Greg Suarez , =?UTF-8?q?Bj=C3=B8rn=20Mork?= To: netdev@vger.kernel.org Return-path: Received: from canardo.mork.no ([148.122.252.1]:51753 "EHLO canardo.mork.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754812AbaE3HcD (ORCPT ); Fri, 30 May 2014 03:32:03 -0400 In-Reply-To: <1401435070-26721-1-git-send-email-bjorn@mork.no> Sender: netdev-owner@vger.kernel.org List-ID: The min_tx_pkt variable decides the cutoff point where the driver will stop padding out NTBs to maximum size. The padding is a tradeoff where we use some USB bus bandwidth to allow the device to receive fixed size buffers. Different devices will have different optimal settings, spanning from no padding at all to padding every NTB. There is no way to automatically figure out which setting is best for a specific device. The default value is a reasonable tradeoff, calculated based on the USB packet size and out NTB max size. This may have to be changed along with any tx_max changes. Signed-off-by: Bj=C3=B8rn Mork --- drivers/net/usb/cdc_ncm.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c index 98c3adb5aea3..80a844e0ae03 100644 --- a/drivers/net/usb/cdc_ncm.c +++ b/drivers/net/usb/cdc_ncm.c @@ -185,6 +185,14 @@ static u32 cdc_ncm_check_tx_max(struct usbnet *dev= , u32 new_tx) return val; } =20 +static ssize_t cdc_ncm_show_min_tx_pkt(struct device *d, struct device= _attribute *attr, char *buf) +{ + struct usbnet *dev =3D netdev_priv(to_net_dev(d)); + struct cdc_ncm_ctx *ctx =3D (struct cdc_ncm_ctx *)dev->data[0]; + + return sprintf(buf, "%u\n", ctx->min_tx_pkt); +} + static ssize_t cdc_ncm_show_rx_max(struct device *d, struct device_att= ribute *attr, char *buf) { struct usbnet *dev =3D netdev_priv(to_net_dev(d)); @@ -209,6 +217,20 @@ static ssize_t cdc_ncm_show_tx_timer_usecs(struct = device *d, struct device_attri return sprintf(buf, "%u\n", ctx->timer_interval / (u32)NSEC_PER_USEC)= ; } =20 +static ssize_t cdc_ncm_store_min_tx_pkt(struct device *d, struct devi= ce_attribute *attr, const char *buf, size_t len) +{ + struct usbnet *dev =3D netdev_priv(to_net_dev(d)); + struct cdc_ncm_ctx *ctx =3D (struct cdc_ncm_ctx *)dev->data[0]; + unsigned long val; + + /* no need to restrict values - anything from 0 to infinity is OK */ + if (kstrtoul(buf, 0, &val)) + return -EINVAL; + + ctx->min_tx_pkt =3D val; + return len; +} + static ssize_t cdc_ncm_store_rx_max(struct device *d, struct device_a= ttribute *attr, const char *buf, size_t len) { struct usbnet *dev =3D netdev_priv(to_net_dev(d)); @@ -256,6 +278,7 @@ static ssize_t cdc_ncm_store_tx_timer_usecs(struct = device *d, struct device_att return len; } =20 +static DEVICE_ATTR(min_tx_pkt, S_IRUGO | S_IWUSR, cdc_ncm_show_min_tx_= pkt, cdc_ncm_store_min_tx_pkt); static DEVICE_ATTR(rx_max, S_IRUGO | S_IWUSR, cdc_ncm_show_rx_max, cdc= _ncm_store_rx_max); 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); @@ -281,6 +304,7 @@ NCM_PARM_ATTR(wNdpOutAlignment, "%u", le16_to_cpu); NCM_PARM_ATTR(wNtbOutMaxDatagrams, "%u", le16_to_cpu); =20 static struct attribute *cdc_ncm_sysfs_attrs[] =3D { + &dev_attr_min_tx_pkt.attr, &dev_attr_rx_max.attr, &dev_attr_tx_max.attr, &dev_attr_tx_timer_usecs.attr, --=20 2.0.0.rc4