linux-toradex.git/drivers/net/can/spi, branch v5.0

can: hi311x: Use level-triggered interrupt

2018-11-09T16:20:08+00:00

If the hi3110 shares the SPI bus with another traffic-intensive device
and packets are received in high volume (by a separate machine sending
with "cangen -g 0 -i -x"), reception stops after a few minutes and the
counter in /proc/interrupts stops incrementing.  Bus state is "active".
Bringing the interface down and back up reconvenes the reception.  The
issue is not observed when the hi3110 is the sole device on the SPI bus.

Using a level-triggered interrupt makes the issue go away and lets the
hi3110 successfully receive 2 GByte over the course of 5 days while a
ks8851 Ethernet chip on the same SPI bus handles 6 GByte of traffic.

Unfortunately the hi3110 datasheet is mum on the trigger type.  The pin
description on page 3 only specifies the polarity (active high):
http://www.holtic.com/documents/371-hi-3110_v-rev-kpdf.do

Cc: Mathias Duckeck 
Cc: Akshay Bhat 
Cc: Casey Fitzpatrick 
Signed-off-by: Lukas Wunner 
Cc: linux-stable 
Signed-off-by: Marc Kleine-Budde

can: hi311x: Work around TX complete interrupt erratum

2018-05-10T16:25:30+00:00

When sending packets as fast as possible using "cangen -g 0 -i -x", the
HI-3110 occasionally latches the interrupt pin high on completion of a
packet, but doesn't set the TXCPLT bit in the INTF register.  The INTF
register contains 0x00 as if no interrupt has occurred.  Even waiting
for a few milliseconds after the interrupt doesn't help.

Work around this apparent erratum by instead checking the TXMTY bit in
the STATF register ("TX FIFO empty").  We know that we've queued up a
packet for transmission if priv->tx_len is nonzero.  If the TX FIFO is
empty, transmission of that packet must have completed.

Note that this is congruent with our handling of received packets, which
likewise gleans from the STATF register whether a packet is waiting in
the RX FIFO, instead of looking at the INTF register.

Cc: Mathias Duckeck 
Cc: Akshay Bhat 
Cc: Casey Fitzpatrick 
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Lukas Wunner 
Acked-by: Akshay Bhat 
Signed-off-by: Marc Kleine-Budde

can: hi311x: Acquire SPI lock on ->do_get_berr_counter

2018-05-10T16:20:51+00:00

hi3110_get_berr_counter() may run concurrently to the rest of the driver
but neglects to acquire the lock protecting access to the SPI device.
As a result, it and the rest of the driver may clobber each other's tx
and rx buffers.

We became aware of this issue because transmission of packets with
"cangen -g 0 -i -x" frequently hung.  It turns out that agetty executes
->do_get_berr_counter every few seconds via the following call stack:

    CPU: 2 PID: 1605 Comm: agetty
    [<7f3f7500>] (hi3110_get_berr_counter [hi311x])
    [<7f130204>] (can_fill_info [can_dev])
    [<80693bc0>] (rtnl_fill_ifinfo)
    [<806949ec>] (rtnl_dump_ifinfo)
    [<806b4834>] (netlink_dump)
    [<806b4bc8>] (netlink_recvmsg)
    [<8065f180>] (sock_recvmsg)
    [<80660f90>] (___sys_recvmsg)
    [<80661e7c>] (__sys_recvmsg)
    [<80661ec0>] (SyS_recvmsg)
    [<80108b20>] (ret_fast_syscall+0x0/0x1c)

agetty listens to netlink messages in order to update the login prompt
when IP addresses change (if /etc/issue contains \4 or \6 escape codes):
https://git.kernel.org/pub/scm/utils/util-linux/util-linux.git/commit/?id=e36deb6424e8

It's a useful feature, though it seems questionable that it causes CAN
bit error statistics to be queried.

Be that as it may, if hi3110_get_berr_counter() is invoked while a frame
is sent by hi3110_hw_tx(), bogus SPI transfers like the following may
occur:

    => 12 00             (hi3110_get_berr_counter() wanted to transmit
                          EC 00 to query the transmit error counter,
                          but the first byte was overwritten by
                          hi3110_hw_tx_frame())

    => EA 00 3E 80 01 FB (hi3110_hw_tx_frame() wanted to transmit a
                          frame, but the first byte was overwritten by
                          hi3110_get_berr_counter() because it wanted
                          to query the receive error counter)

This sequence hangs the transmission because the driver believes it has
sent a frame and waits for the interrupt signaling completion, but in
reality the chip has never sent away the frame since the commands it
received were malformed.

Fix by acquiring the SPI lock in hi3110_get_berr_counter().

I've scrutinized the entire driver for further unlocked SPI accesses but
found no others.

Cc: Mathias Duckeck 
Cc: Akshay Bhat 
Cc: Casey Fitzpatrick 
Cc: Stef Walter 
Cc: Karel Zak 
Cc: stable@vger.kernel.org # v4.12+
Signed-off-by: Lukas Wunner 
Reviewed-by: Akshay Bhat 
Signed-off-by: Marc Kleine-Budde

drivers/net: Use octal not symbolic permissions

2018-03-26T16:07:49+00:00

Prefer the direct use of octal for permissions.

Done with checkpatch -f --types=SYMBOLIC_PERMS --fix-inplace
and some typing.

Miscellanea:

o Whitespace neatening around these conversions.

Signed-off-by: Joe Perches 
Reviewed-by: Wei Liu 
Signed-off-by: David S. Miller

can: mcp251x: mcp251x_setup(): remove unused parameter "struct mcp251x_priv *priv"

2018-01-05T10:12:08+00:00

The 2nd parameter of mcp251x_setup() "struct mcp251x_priv *priv" is not
used, so remove it.

Suggested-by: Oleksij Rempel 
Signed-off-by: Marc Kleine-Budde

can: hi311x: Add Holt HI-311x CAN driver

2017-04-04T15:35:59+00:00

This patch adds support for the Holt HI-311x CAN controller. The HI311x
CAN controller is capable of transmitting and receiving standard data
frames, extended data frames and remote frames. The HI311x interfaces
with the host over SPI.

Datasheet: www.holtic.com/documents/371-hi-3110_v-rev-jpdf.do

Signed-off-by: Akshay Bhat 
Acked-by: Wolfgang Grandegger 
Signed-off-by: Marc Kleine-Budde

can: mcp251x: add message about sucessful/unsuccessful probe

2016-06-23T09:23:49+00:00

Silent ignorance of errors during probe procedure is a bad thing, this
patch fixes it. Extra message added for hardware initialization
failure. Such common issues are mostly caused by wrong wiring.  Message
about success added as well, it should be useful to debug new hardware
configuration, especially in case of several CAN buses.

Signed-off-by: Ed Spiridonov 
Signed-off-by: Marc Kleine-Budde

can: mcp251x: Replace create_freezable_workqueue with alloc_workqueue

2016-05-09T09:07:28+00:00

Replace scheduled to be removed create_freezable_workqueue with
alloc_workqueue.

priv->wq should be explicitly set as freezable to ensure it is frozen
in the suspend sequence and work items are drained so that no new work
item starts execution until thawed. Thus, use of WQ_FREEZABLE flag
here is required.

WQ_MEM_RECLAIM flag has been set here to ensure forward progress
regardless of memory pressure.

The order of execution is not important so set @max_active as 0.

Signed-off-by: Amitoj Kaur Chawla 
Acked-by: Tejun Heo 
Signed-off-by: Marc Kleine-Budde

can: mcp251x: avoid write to error flag register if it's unnecessary

2016-03-04T07:45:17+00:00

Only two bits (RX0OVR and RX1OVR) are writable in EFLG, write is useless
if these bits aren't set.

Signed-off-by: Ed Spiridonov 
Signed-off-by: Marc Kleine-Budde

spi: Drop owner assignment from spi_drivers

2015-10-28T01:30:17+00:00

An spi_driver does not need to set an owner, it will be populated by the
driver core.

Signed-off-by: Andrew F. Davis 
Acked-by: Jonathan Cameron 
Signed-off-by: Mark Brown