kernel/include/linux/usb/cdc_ncm.h, branch linux-3.17.y

net: cdc_ncm: fix 64bit division build error

2014-05-21T05:56:06Z

The upper timer_interval limit is arbitrary and much higher than anything usable in the real world. Reducing it from 15s to ~4s to make the timer_interval fit in an u32 does not make much difference. The limit is still outside the practical bounds. This eliminates the need for a 64bit timer_interval, fixing a build error related to 64bit division: drivers/built-in.o: In function `cdc_ncm_get_coalesce': ak8975.c:(.text+0x1ac994): undefined reference to `__aeabi_uldivmod' Reported-by: Stephen Rothwell Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller

net: cdc_ncm: remove redundant "disconnected" flag

2014-05-17T02:39:02Z

Calling netif_carrier_{on,off} is sufficient. There is no need to duplicate the carrier state in a driver specific flag. Acked-by: Enrico Mioso Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller

net: cdc_ncm: use sane defaults for rx/tx buffers

2014-05-17T02:39:02Z

Lots of devices request much larger buffers than reasonable. This cause real problems for users of hosts with limited resources. Reducing the default buffer size to 16kB for such devices is a reasonable trade-off between allowing them to aggregate traffic and avoiding memory exhaustion on resource restrained hosts. Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller

net: cdc_ncm/cdc_mbim: adding NCM protocol statistics

2014-05-17T02:39:01Z

To have an idea of the effects of the protocol coalescing it's useful to have some counters showing the different aspects. Due to the asymmetrical usbnet interface the netdev rx_bytes counter has been counting real received payload, while the tx_bytes counter has included the NCM/MBIM framing overhead. This overhead can be many times the payload because of the aggressive padding strategy of this driver, and will vary a lot depending on device and traffic. With very few exceptions, users are only interested in the payload size. Having an somewhat accurate payload byte counter is particularly important for mobile broadband devices, which many NCM devices and of course all MBIM devices are. Users and userspace applications will use this counter to monitor account quotas. Having protocol specific counters for the overhead, we are now able to correct the tx_bytes netdev counter so that it shows the real payload Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller

net: cdc_ncm: set reasonable padding limits

2014-05-17T02:39:01Z

We pad frames larger than X to maximum size for devices which don't need a ZLP after maximum sized frames. This allows the device to optimize its transfers for one fixed buffer size. X was arbitrarily set at 512 bytes regardless of real buffer maximum, causing extreme overheads due to excessive padding of larger tx buffers. Limit the padding to at most 3 full USB packets, still allowing the overhead to payload ratio of 3/1. Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller

net: cdc_ncm: use true max dgram count for header estimates

2014-05-17T02:39:01Z

Many newer NCM and MBIM devices will request a maximum tx datagram count which is much smaller than our hard-coded absolute max. We can reduce the overhead without sacrificing any of the simplicity for these devices, by simply using the true negotiated count in when calculated the maximum NTH and NDP header sizes. Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller

net: cdc_ncm: use ethtool to tune coalescing settings

2014-05-17T02:39:01Z

Datagram coalescing is an integral part of the NCM and MBIM protocols, intended to reduce the interrupt load primarily on the device end of the USB link. As with all coalescing solutions, there is a trade-off between buffering and interrupts. The current defaults are based on the assumption that device side buffers should be the limiting factor. However, many modern high speed LTE modems suffers from buffer-bloat, making this assumption fail. This results in sub-optimal performance due to excessive coalescing. And in cases where such modems are connected to cheap embedded hosts there is often severe buffer allocation issues, giving very noticeable performance degradation . A start on improving this is going from build time hard coded limits to per device user configurable limits. The ethtool coalescing API was selected as user interface because, although the tuned values are buffer sizes, these settings directly control datagram coalescing. Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller

net: cdc_ncm/cdc_mbim: rework probing of NCM/MBIM functions

2014-05-13T21:46:09Z

The NCM class match in the cdc_mbim driver is confusing and cause unexpected behaviour. The USB core guarantees that a USB interface is in altsetting 0 when probing starts. This means that devices implementing a NCM 1.0 backwards compatible MBIM function (a "NCM/MBIM function") always hit the NCM entry in the cdc_mbim driver match table. Such functions will never match any of the MBIM entries. This causes unexpeced behaviour for cases where the NCM and MBIM entries are differet, which is currently the case for all except Ericsson devices. Improve the probing of NCM/MBIM functions by looking up the device again in the cdc_mbim match table after switching to the MBIM identity. The shared altsetting selection is updated to better accommodate the new probing logic, returning the preferred altsetting for the control interface instead of the data interface. The control interface altsetting update is moved to the cdc_mbim driver. It is never necessary to change the control interface altsetting for NCM. Cc: Greg Suarez Reported by: Yu-an Shih Signed-off-by: Bjørn Mork Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2014-03-26T00:29:20Z

Conflicts: Documentation/devicetree/bindings/net/micrel-ks8851.txt net/core/netpoll.c The net/core/netpoll.c conflict is a bug fix in 'net' happening to code which is completely removed in 'net-next'. In micrel-ks8851.txt we simply have overlapping changes. Signed-off-by: David S. Miller

net: cdc_ncm: respect operator preferred MTU reported by MBIM

2014-03-20T20:57:35Z

According to "Universal Serial Bus Communications Class Subclass Specification for Mobile Broadband Interface Model, Revision 1.0, Errata-1" published by USB-IF, the wMTU field of the MBIM extended functional descriptor indicates the operator preferred MTU for IP data streams. This patch modifies cdc_ncm_setup to ensure that the MTU value set on the usbnet device does not exceed the operator preferred MTU indicated by wMTU if the MBIM device exposes a MBIM extended functional descriptor. Signed-off-by: Ben Chan Signed-off-by: David S. Miller