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: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The mandatory GetNtbParameters control request is an important part of
the host <-> device protocol negotiation in CDC NCM (and CDC MBIM). It
gives device limits which the host must obey when configuring the
protocol aggregation variables. The driver will enforce this by
rejecting attempts to set any of the tunable variables to a value
which is not supported by the device.  Exporting the parameter block
helps userspace decide which values are allowed without resorting
to trial and error.
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The ethtool coalesce API is not applicable for this driver. Forcing
it to fit the NCM aggregation redefined the API in a driver specific
way, which is much worse than defining a clean new API. These ethtool
coalesce functions have therefore been replaced by a new sysfs API.
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Attach a driver specific sysfs group to the netdev, and use it
for the rx/tx aggregation variables.

The datagram aggregation defined by the CDC NCM specification is
specific to this device class (including CDC MBIM). Using the
ethtool interrupt coalesce API as an interface to the aggregation
parameters redefined that API in a driver specific and confusing
way.  A sysfs group
 - makes it clear that this is a driver specific userspace API, and
 - allows us to export the real values instead of some translated
   version, and
 - lets us include more aggregation variables which were impossible
   to force into the ethtool API.

Additionally, using sysfs allows tuning the driver on space
constrained hosts where userspace tools like ethtool are undesired.
Suggested-by: NPeter Stuge <peter@stuge.se>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It doesn't matter whether the buffer size goes up or down.  We have to
keep usbnet and device syncronized to be able to split transfers at the
correct boundaries. The spec allow skipping short packets when using
max sized transfers.  If we don't tell usbnet about our new expected rx
buffer size, then it will merge and/or split NTBs.  The driver does not
support this, and the result will be lots of framing errors.

Fix by always reallocating usbnet rx buffers when the rx_max value
changes.

Fixes: 68864abf ("net: cdc_ncm: support rx_max/tx_max updates when running")
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We are calling usbnet_start_xmit() to flush any remaining data,
depending on the side effect that tx_curr_skb is set to NULL,
ensuring a new allocation using the updated tx_max.  But this
side effect will only happen if there were any cached data ready
to transmit. If not, then an empty tx_curr_skb is still allocated
using the old tx_max size. Free it to avoid a buffer overrun.

Fixes: 68864abf ("net: cdc_ncm: support rx_max/tx_max updates when running")
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Cloning the big skbs we use for USB buffering chokes up TCP and
SCTP because the socket memory limits are hitting earlier than
they should. It is better to unconditionally copy the unwrapped
packets to freshly allocated skbs.
Reported-by: NJim Baxter <jim_baxter@mentor.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There is a typo here where we test for USB_CDC_NCM_NTH32_SIGN instead
of USB_CDC_NCM_NTB32_SUPPORTED.  The test probably still works as
written because 0x686D636E has (1 << 1) set and doesn't have (1 << 0)
set.

Fixes: f8afb73d ('net: cdc_ncm: factor out one-time device initialization')
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We can end up with a freshly allocated tx_curr_skb with no frames
in it.  In this case it does not make any sense to start the timer.
This avoids the timer periodically trying to start tx when there
is nothing in the queue.
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Calling netif_carrier_{on,off} is sufficient.  There is no need
to duplicate the carrier state in a driver specific flag.
Acked-by: NEnrico Mioso <mrkiko.rs@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Reported-by: NJoe Perches <joe@perches.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Finish the rx_max/tx_max setup by flushing buffers and
informing usbnet about the changes.  This way, the settings
can be modified while the netdev is up and running.
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that we have split out the part of the device setup
which MUST be done with the data interface in altsetting 0,
we can delay the rest of the initialization. This allows us
to move some of post-init buffer size config from bind to
the appropriate setup function.

The purpose of this refactoring is to collect all code
adjusting the rx_max and tx_max buffers in one place, so
that it is easier to call it from multiple call sites.
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Split the parts of setup dealing with device initialization from
parts just setting defaults for attributes which might be
changed after initialization.

Some commands of the device initialization are only allowed when
the data interface is in its disabled altsetting, so we must
separate them out of we are to allow rerunning parts of setup.
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Split out the part of setup dealing with updating the rx_max
and tx_max buffer sizes so that this code can be reused for
dynamically updating the limits.
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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 <gsuarez@smithmicro.com>
Reported by: Yu-an Shih <yshih@nvidia.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 4d619f62 ("net: cdc_ncm: no point in filling up the NTBs
if we send ZLPs") changed the padding logic for devices with the ZLP
flag set.  This meant that frames of any size will be sent without
additional padding, except for the single byte added if the size is
a multiple of the USB packet size. But if the unpadded size is
identical to the maximum frame size, and the maximum size is a
multiplum of the USB packet size, then this one-byte padding will
overflow the buffer.

Prevent padding if already at maximum frame size, letting usbnet
transmit a ZLP instead in this case.

Fixes: 4d619f62 ("net: cdc_ncm: no point in filling up the NTBs if we send ZLPs")
Reported by: Yu-an Shih <yshih@nvidia.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: NBen Chan <benchan@chromium.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is a context modified revert of commit 6a9612e2
("net: cdc_ncm: remove ncm_parm field") which introduced
a NCM specification violation, causing setup errors for
some devices. These errors resulted in the device and
host disagreeing about shared settings, with complete
failure to communicate as the end result.

The NCM specification require that many of the NCM specific
control reuests are sent only while the NCM Data Interface
is in alternate setting 0. Reverting the commit ensures that
we follow this requirement.

Fixes: 6a9612e2 ("net: cdc_ncm: remove ncm_parm field")
Reported-and-tested-by: NPasi Kärkkäinen <pasik@iki.fi>
Reported-by: NThomas Schäfer <tschaefer@t-online.de>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>.   Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.

This covers everything under drivers/net except for wireless, which
has been submitted separately.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is harmless but cdc_ncm_setup() returns negative error codes
truncated to u8 values.  There is only one caller and treats all
non-zero returns as errors but doesn't store the the return code.  So
the code works correctly but it's messy and upsets the static checkers.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Remove device IDs of NCM-like (but not NCM-conformant) devices, that are
handled by the huawwei_cdc_ncm driver now.
Signed-off-by: NEnrico Mioso <mrkiko.rs@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some drivers implementing NCM-like protocols, may re-use those functions, as is
the case in the huawei_cdc_ncm driver.
Export them via EXPORT_SYMBOL_GPL, in accordance with how other functions have
been exported.
Signed-off-by: NEnrico Mioso <mrkiko.rs@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are MBIM devices out there reporting

  dwNtbInMaxSize=2048 dwNtbOutMaxSize=2048

and since the spec require a datagram max size of at least
2048, this means that a full sized datagram will never fit.

Still, sending larger NTBs than the device supports is not
going to help.  We do not have any other options than either
 a) refusing to bindi, or
 b) respect the insanely low value.

Alternative b will at least make these devices work, so go
for it.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Make it a bit easier for users to figure out what goes
wrong when bind fails.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Most setup errors are ignored to ensure maximum firmware
compatibilty.  But GET_NTB_PARAMETERS and the functional
descriptors are required.  Use proper error codes and
log level if these fail.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rewriting the "set max datagram" part of dc_ncm_setup to
separate the selection and validatation of the size from
the code which optionally informs the device of this
value.  This ensures that we use the correct value
regardless of device support for the get and set commands.

Removing some of the many indent levels while doing this
to make the code more readable.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Converting the constants used in these comparisons at build
time instead of converting the variables for every received
frame at run time.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These signatures are well known bit patterns, mostly made up
of ascii characters.  Mentally parsing works best if they
are printed in hex.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Take advantage of standard device name prefixing and
netdevice msglvl control where possible.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix cut'n'paste typo.  Log the bogus length and not the
irrelevant signature.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

usbnet use the hard_mtu value for sizing the tx queue and nothing
else.  We will be transmitting buffers of up to tx_max size, so
that's the proper value to give usbnet.

The individual datagram size is completely irrelevant here.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

No need to keep this code duplicated from usbnet.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

These functions were merely wrappers around the usbnet
variants.  Remove them.

Cc: Alexey Orishko <alexey.orishko@gmail.com>
Signed-off-by: NBjørn Mork <bjorn@mork.no>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>