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687 commits

Author SHA1 Message Date
Tyler Hall a8e83b1753 slcan: Port write_wakeup deadlock fix from slip
The commit "slip: Fix deadlock in write_wakeup" fixes a deadlock caused
by a change made in both slcan and slip. This is a direct port of that
fix.

Signed-off-by: Tyler Hall <tylerwhall@gmail.com>
Cc: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: Andre Naujoks <nautsch2@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-16 21:29:13 -07:00
David S. Miller c99f7abf0e Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	include/net/inetpeer.h
	net/ipv6/output_core.c

Changes in net were fixing bugs in code removed in net-next.

Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-03 23:32:12 -07:00
Oliver Hartkopp 45fb4f8d81 can: only rename enabled led triggers when changing the netdev name
Commit a1ef7bd9fc ("can: rename LED trigger name on netdev renames") renames
the led trigger names according to the changed netdevice name.

As not every CAN driver supports and initializes the led triggers, checking for
the CAN private datastructure with safe_candev_priv() in the notifier chain is
not enough.

This patch adds a check when CONFIG_CAN_LEDS is enabled and the driver does not
support led triggers.

For stable 3.9+

Cc: Fabio Baltieri <fabio.baltieri@gmail.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-27 15:05:41 +02:00
Kedareswara rao Appana b1201e44f5 can: xilinx CAN controller support
This patch adds xilinx CAN controller support. This driver supports both ZYNQ
CANPS and Soft IP AXI CAN controller.

Signed-off-by: Kedareswara rao Appana <appanad@xilinx.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-26 09:36:31 +02:00
David S. Miller 54e5c4def0 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/bonding/bond_alb.c
	drivers/net/ethernet/altera/altera_msgdma.c
	drivers/net/ethernet/altera/altera_sgdma.c
	net/ipv6/xfrm6_output.c

Several cases of overlapping changes.

The xfrm6_output.c has a bug fix which overlaps the renaming
of skb->local_df to skb->ignore_df.

In the Altera TSE driver cases, the register access cleanups
in net-next overlapped with bug fixes done in net.

Similarly a bug fix to send ALB packets in the bonding driver using
the right source address overlaps with cleanups in net-next.

Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-24 00:32:30 -04:00
Marc Kleine-Budde cf68f517c5 can: gs_usb: gs_destroy_candev(): fix use after free
This patch fixes a use after free of "dev" in gs_destroy_candev().

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-21 13:04:20 +02:00
Stephane Grosjean 0b5a958cf4 can: peak_pci: prevent use after free at netdev removal
As remarked by Christopher R. Baker in his post at

http://marc.info/?l=linux-can&m=139707295706465&w=2

there's a possibility for an use after free condition at device removal.

This simplified patch introduces an additional variable to prevent the issue.
Thanks for catching this.

Cc: linux-stable <stable@vger.kernel.org>
Reported-by: Christopher R. Baker <cbaker@rec.ri.cmu.edu>
Signed-off-by: Stephane Grosjean <s.grosjean@peak-system.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-21 08:17:03 +02:00
Maximilian Schneider d08e973a77 can: gs_usb: Added support for the GS_USB CAN devices
The Geschwister Schneider Family of devices are galvanically isolated USB2.0 to
CAN2.0A/B adapters. Currently two form factors are available, a tethered dongle
in a rugged enclosure, and mini-pci-e card.

Signed-off-by: Maximilian Schneider <max@schneidersoft.net>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-19 09:38:25 +02:00
Sergei Shtylyov fd1159318e can: add Renesas R-Car CAN driver
Add support for the CAN controller found in Renesas R-Car SoCs.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-19 09:38:23 +02:00
Pavel Machek a9c692099e can: c_can: add hwinit support for non-TI devices
Non-TI chips (including socfpga) needs different raminit sequence. Implement
it.

Tested-by: Thor Thayer <tthayer@altera.com>
Signed-off-by: Thor Thayer <tthayer@altera.com>
Signed-off-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-19 09:38:23 +02:00
Pavel Machek ccbc5357db can: c_can: Add and make use of 32-bit accesses functions
Add helpers for 32-bit accesses and replace open-coded 32-bit access
with calls to helpers. Minimum changes are done to the pci case, as I
don't have access to that hardware.

Tested-by: Thor Thayer <tthayer@altera.com>
Signed-off-by: Thor Thayer <tthayer@altera.com>
Signed-off-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-19 09:38:22 +02:00
Pavel Machek e07e83ae60 can: c_can: make {read,write}_reg functions const
This patch makes the {read,write}_reg functions const, this is a preparation to
make use of {read,write}_reg in the hwinit callback.

Signed-off-by: Thor Thayer <tthayer@altera.com>
Signed-off-by: Pavel Machek <pavel@denx.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-19 09:38:22 +02:00
Jean Delvare fdddfab5c9 can: pch_can: Fix Kconfig dependencies
The pch_can driver is for a companion chip to the Intel Atom E600
series processors. These are 32-bit x86 processors so the driver is
only needed on X86_32. Add COMPILE_TEST as an alternative, so that the
driver can still be build-tested elsewhere.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-19 09:38:22 +02:00
Jean Delvare d01481c35a can: mscan: Fix Kconfig dependencies
The only driver based on MSCAN at the moment is for PPC machines,
so it makes no sense to present the menu on M68K. The menu will always
be empty there.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-19 09:38:21 +02:00
Jean Delvare eeaf4448c8 can: at91_can: Fix Kconfig dependencies
The at91_can driver is AT91-specific so it should depend on ARCH_AT91
rather than just ARM. Add COMPILE_TEST as an alternative, so that the
driver can still be build-tested elsewhere.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-19 09:38:21 +02:00
Dan Carpenter e1dfefebae can: mcp251x: fix coccinelle warnings
drivers/net/can/spi/mcp251x.c:953:7-27: ERROR: Threaded IRQ with no primary handler requested without IRQF_ONESHOT

 Make sure threaded IRQs without a primary handler are always request with
 IRQF_ONESHOT

Generated by: scripts/coccinelle/misc/irqf_oneshot.cocci

CC: Stefano Babic <sbabic@denx.de>
CC: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-19 09:38:07 +02:00
Oliver Hartkopp 524369e239 can: c_can: remove obsolete STRICT_FRAME_ORDERING Kconfig option
In 2b9aecdce2 ("can: c_can: Disable rx split as workaround") a new Kconfig
option was introduced as a workaround. The tests performed by Alexander Stein
confirmed this option to be obsolete with all the other cleanups and fixes
that had been discussed that time:
http://marc.info/?l=linux-can&m=139746476821294&w=2

Both (author and tester) agreed to remove this Kconfig option again:
http://marc.info/?l=linux-can&m=139883820714229&w=2

As some more cleanups took place since then a simple revert is not possible.
This patch removes the entire option as it would behave when disabled.
Further beautification’s can be done later.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-19 09:03:06 +02:00
David S. Miller 5f013c9bc7 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	drivers/net/ethernet/altera/altera_sgdma.c
	net/netlink/af_netlink.c
	net/sched/cls_api.c
	net/sched/sch_api.c

The netlink conflict dealt with moving to netlink_capable() and
netlink_ns_capable() in the 'net' tree vs. supporting 'tc' operations
in non-init namespaces.  These were simple transformations from
netlink_capable to netlink_ns_capable.

The Altera driver conflict was simply code removal overlapping some
void pointer cast cleanups in net-next.

Signed-off-by: David S. Miller <davem@davemloft.net>
2014-05-12 13:19:14 -04:00
Kurt Van Dijck 0f8dced5ef can: softing: remove unused sysfs attributes
'frequency' indicates the embedded cpu's frequency, but that
should not be necessary for any purpose.
'txpending' is an attribute for debugging.

Signed-off-by: Kurt Van Dijck <kurt.van.dijck@eia.be>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-25 00:09:03 +02:00
Kurt Van Dijck ec2e11ed3f can: softing: drop 'channel' sysfs attribute
netdev->dev_id obsoletes this property.
None of the remaining properties contribute to udev detection methods.
The regular calls for the sysfs group can thus safely be restored.

Signed-off-by: Kurt Van Dijck <kurt.van.dijck@eia.be>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-25 00:08:58 +02:00
Alexander Stein abcd7f750a can: c_can: Add support for eg20t (pch_can)
Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Acked-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-25 00:08:43 +02:00
Olivier Sobrie 8e964fe21d can: usb: Kconfig: Improve help for CAN_KVASER_USB
Add two new USB devices supported by the driver and fix bad
english.

Signed-off-by: Olivier Sobrie <olivier@sobrie.be>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:54:16 +02:00
Olivier Sobrie b4f20130af can: kvaser_usb: add support for Kvaser Leaf v2 and usb mini PCIe
This patch adds support for the Kvaser Leaf v2 and Leaf usb mini
PCIe card.

Signed-off-by: Olivier Sobrie <olivier@sobrie.be>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:54:16 +02:00
Olivier Sobrie e59e36e733 can: kvaser_usb: add retries/timeout to kvaser_usb_wait_msg()
On some Kvaser hardware, the firmware returns extra messages after the
request for card info. For instance on a Leaf Light v2:
  --> CMD_GET_CARD_INFO
  <-- CMD_USB_THROTTLE
  <-- CMD_GET_CARD_INFO2
  <-- CMD_GET_CARD_INFO_REQ
When it happens, the probing function fails because we only read
the first usb message.

To overcome this issue, we add a mechanism of retries to the
kvaser_usb_wait_msg() function.

I tested this patch with the following hardware:
 - Kvaser Leaf Light
 - Kvaser Leaf Light v2
 - Kvaser USBCan R

This patch is necessary for the Leaf Light v2 hardware.

Signed-off-by: Olivier Sobrie <olivier@sobrie.be>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:54:16 +02:00
Stefano Babic 869ba1e67a can: move SPI drivers into a separate directory
Create a directory for all CAN drivers using SPI and move mcp251x driver there.

Signed-off-by: Stefano Babic <sbabic@denx.de>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:54:16 +02:00
Alexander Shiyan ee967fffd9 can: mcp251x: Improve mcp251x_hw_probe()
This patch adds check for mcp251x_hw_reset() result on startup and
removes unnecessary checking for CANSTAT register since this value
is being checked in mcp251x_hw_reset().

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Tested-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:54:15 +02:00
Alexander Shiyan ff06d611a3 can: mcp251x: Improve mcp251x_hw_reset()
The MCP251x utilizes an oscillator startup timer (OST), which holds the
chip in reset, to insure that the oscillator has stabilized before the
internal state machine begins to operate. The OST maintains reset for
the first 128 OSC clock cycles after power up or reset.
So, this patch removes unnecessary loops and reduce delay for power on
and reset to the safe value.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Tested-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:54:15 +02:00
Alexander Shiyan 31473c286c can: mcp251x: Check return value of spi_setup()
This patch moves setup of SPI bus a bit earlier and adds check for spi_setup()
result to be sure SPI bus is communicating with the device properly.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Tested-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:54:15 +02:00
Alexander Stein 367525c8c2 can: slcan: Fix spinlock variant
slc_xmit is called within softirq context and locks sl->lock, but
slcan_write_wakeup is not softirq context, so we need to use
spin_[un]lock_bh!
Detected using kernel lock debugging mechanism.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:32:41 +02:00
Oliver Hartkopp d482443244 can: fix return value from can_get_bittiming()
When trying to set a data bitrate on non CAN FD devices the 'ip' tool
answers with:

	RTNETLINK answers: Unknown error 524

Rename '-ENOTSUPP' to '-EOPNOTSUPP' so that 'ip' answers correctly:

       RTNETLINK answers: Operation not supported

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:30:39 +02:00
Oliver Hartkopp a9edcdedbd can: sja1000_isa: add locking for indirect register access mode
When accessing the SJA1000 controller registers in the indirect access mode,
writing the register number and reading/writing the data has to be an atomic
attempt.

As the sja1000_isa driver is an old style driver with a fixed number of
instances the locking variable depends on the same index like all the other
configuration elements given on the module command line.

As a positive side effect dev->dev_id is populated by the instance index,
which was missing in 3e66d0138c ("can: populate netdev::dev_id for udev
discrimination").

Reported-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:22:53 +02:00
Wolfgang Grandegger 78c181bc8a can: c_can_pci: enable PCI bus master only for MSI
Coverity complains that c_can_pci_probe() calls pci_enable_msi() without
checking the result:

CID 712278 (#1 of 1): Unchecked return value (CHECKED_RETURN) 3. check_return:
Calling pci_enable_msi_block without checking return value (as is done
elsewhere 88 out of 105 times).
 88        pci_enable_msi(pdev);

This is CID 712278.

Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Reported-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:22:52 +02:00
Wolfram Sang f323d7a1d2 can: c_can: use proper type for 'instance'
Commit 6439fbce10 (can: c_can: fix error checking of priv->instance in
probe()) found the warning but applied a suboptimal solution. Since, both
pdev->id and of_alias_get_id() return integers, it makes sense to convert the
variable to an integer and avoid the cast.

Signed-off-by: Wolfram Sang <wsa@sang-engineering.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:09:01 +02:00
Thomas Gleixner 939415973f can: c_can: Speed up tx buffer invalidation
It's suffcient to kill the TXIE bit in the message control register
even if the documentation of C and D CAN says that it's not allowed to
do that while MSGVAL is set. Reality tells a different story and this
change gives us another 2% of CPU back for not waiting on I/O.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:09:01 +02:00
Thomas Gleixner 35bdafb576 can: c_can: Remove tx locking
Mark suggested to use one IF for the softirq and the other for the
xmit function to avoid the xmit lock.

That requires to write the frame into the interface first, then handle
the echo skb and store the dlc before committing the TX request to the
message ram.

We use an atomic to handle the active buffers instead of reading the
MSGVAL register as thats way faster especially on PCH/x86.

Suggested-by: Mark <mark5@del-llc.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:09:01 +02:00
Thomas Gleixner d48071be6c can: c_can: Use proper u32 variables in c_can_write_msg_object()
Instead of obfuscating the code by artificial 16 bit splits use the
proper 32 bit assignments and split the result when writing to the
interface.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:09:01 +02:00
Thomas Gleixner 23ef0a895d can: c_can: Cleanup c_can_write_msg_object()
Remove the MASK from the TX transfer side.

Make the code readable and get rid of the annoying IFX_WRITE_XXX_16BIT
macros which are just obfuscating the code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:09:01 +02:00
Thomas Gleixner 7af28630b8 can: c_can: Cleanup c_can_msg_obj_put/get()
Sigh!

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:09:00 +02:00
Thomas Gleixner b07faaaf1f can: c_can: Cleanup c_can_inval_msg_object()
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:09:00 +02:00
Thomas Gleixner 8ff2de0fb4 can: c_can: Cleanup setup of receive buffers
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:09:00 +02:00
Thomas Gleixner 4fb6dccd13 can: c_can: Cleanup c_can_read_msg_object()
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:09:00 +02:00
Thomas Gleixner 2d5f4f8569 can: c_can: Cleanup irq enable/disable
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:09:00 +02:00
Thomas Gleixner d61d09de02 can: c_can: Work around C_CAN RX wreckage
Alexander reported that the new optimized handling of the RX fifo
causes random packet loss on Intel PCH C_CAN hardware.

After a few fruitless debugging sessions I got hold of a PCH (eg20t)
afflicted system. That machine does not have the CAN interface wired
up, but it was possible to reproduce the issue with the HW loopback
mode.

As Alexander observed correctly, clearing the NewDat flag along with
reading out the message buffer causes that issue on C_CAN, while D_CAN
handles that correctly.

Instead of restoring the original message buffer handling horror the
following workaround solves the issue:

    transfer buffer to IF without clearing the NewDat
    handle the message
    clear NewDat bit

That's similar to the original code but conditional for C_CAN.

I really wonder why all user manuals (C_CAN, Intel PCH and some more)
recommend to clear the NewDat bit right away. The knows it all Oracle
operated by Gurgle does not unearth any useful information either. I
simply cannot believe that we are the first to uncover that HW issue.

Reported-and-tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:09:00 +02:00
Thomas Gleixner 2b9aecdce2 can: c_can: Disable rx split as workaround
The RX buffer split causes packet loss in the hardware:

What happens is:

RX Packet 1 --> message buffer 1 (newdat bit is not cleared)
RX Packet 2 --> message buffer 2 (newdat bit is not cleared)
RX Packet 3 --> message buffer 3 (newdat bit is not cleared)
RX Packet 4 --> message buffer 4 (newdat bit is not cleared)
RX Packet 5 --> message buffer 5 (newdat bit is not cleared)
RX Packet 6 --> message buffer 6 (newdat bit is not cleared)
RX Packet 7 --> message buffer 7 (newdat bit is not cleared)
RX Packet 8 --> message buffer 8 (newdat bit is not cleared)

Clear newdat bit in message buffer 1
Clear newdat bit in message buffer 2
Clear newdat bit in message buffer 3
Clear newdat bit in message buffer 4
Clear newdat bit in message buffer 5
Clear newdat bit in message buffer 6
Clear newdat bit in message buffer 7
Clear newdat bit in message buffer 8

Now if during that clearing of newdat bits, a new message comes in,
the HW gets confused and drops it.

It does not matter how many of them you clear. I put a delay between
clear of buffer 1 and buffer 2 which was long enough that the message
should have been queued either in buffer 1 or buffer 9. But it did not
show up anywhere. The next message ended up in buffer 1. So the
hardware lost a packet of course without telling it via one of the
error handlers.

That does not happen on all clear newdat bit events. I see one of 10k
packets dropped in the scenario which allows us to reproduce. But the
trace looks always the same.

Not splitting the RX Buffer avoids the packet loss but can cause
reordering. It's hard to trigger, but it CAN happen.

With that mode we use the HW as it was probably designed for. We read
from the buffer 1 upwards and clear the buffer as we get the
message. That's how all microcontrollers use it. So I assume that the
way we handle the buffers was never really tested. According to the
public documentation it should just work :)

Let the user decide which evil is the lesser one.

[ Oliver Hartkopp: Provided a sane config option and help text and
  made me switch to favour potential and unlikely reordering over
  packet loss ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:09:00 +02:00
Thomas Gleixner fa39b54ccf can: c_can: Get rid of pointless interrupts
The driver handles pointlessly TWO interrupts per packet. The reason
is that it enables the status interrupt which fires for each rx and tx
packet and it enables the per message object interrupts as well.

The status interrupt merily acks or in case of D_CAN ignores the TX/RX
state and then the message object interrupt fires.

The message objects interrupts are only useful if all message objects
have hardware filters activated.

But we don't have that and its not simple to implement in that driver
without rewriting it completely.

So we can ditch the message object interrupts and handle the RX/TX
right away from the status interrupt. Instead of TWO we handle ONE.

Note: We must keep the TXIE/RXIE bits in the message buffers because
the status interrupt alone is not reliable enough in corner cases.

If we ever have the need for HW filtering, then this code needs a
complete overhaul and we can think about it then. For now we prefer a
lower interrupt load.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:08:57 +02:00
Thomas Gleixner b9011aae93 can: c_can: Avoid status register update for D_CAN
On D_CAN the RXOK, TXOK and LEC bits are cleared/set on read of the
status register. No need to update them.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:08:57 +02:00
Thomas Gleixner 6b48ff8d93 can: c_can: Simplify buffer reenabling
Instead of writing to the message object we can simply clear the
NewDat bit with the get method.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:08:57 +02:00
Thomas Gleixner 1da394d889 can: c_can: Always update error stats
If the allocation of the error skb fails, we still want to see the
error statistics.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:08:57 +02:00
Thomas Gleixner 097aec1968 can: c_can: Fix berr reporting
Reading the LEC type with

  return (mode & ENABLED) && (status & LEC_MASK);

is not guaranteed to return (status & LEC_MASK) if the enabled bit in
mode is set. It's guaranteed to return 0 or !=0.

Remove the inline function and call unconditionally into the
berr_handling code and return early when the reporting is disabled.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:08:56 +02:00
Thomas Gleixner f058d548e8 can: c_can: Handle state change correctly
If the allocation of an error skb fails, the state change handling
returns w/o doing any work. That leaves the interface in a wreckaged
state as the internal status is wrong.

Split the interface handling and the skb handling.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-04-24 22:08:56 +02:00