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path: root/drivers/net/can/c_can
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2017-01-30drivers: net: generalize napi_complete_done()Eric Dumazet
napi_complete_done() allows to opt-in for gro_flush_timeout, added back in linux-3.19, commit 3b47d30396ba ("net: gro: add a per device gro flush timer") This allows for more efficient GRO aggregation without sacrifying latencies. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-01-18can: c_can_pci: fix null-pointer-deref in c_can_start() - set device pointerEinar Jón
The priv->device pointer for c_can_pci is never set, but it is used without a NULL check in c_can_start(). Setting it in c_can_pci_probe() like c_can_plat_probe() prevents c_can_pci.ko from crashing, with and without CONFIG_PM. This might also cause the pm_runtime_*() functions in c_can.c to actually be executed for c_can_pci devices - they are the only other place where priv->device is used, but they all contain a null check. Signed-off-by: Einar Jón <tolvupostur@gmail.com> Cc: linux-stable <stable@vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2016-06-20can: c_can: Update D_CAN TX and RX functions to 32 bit - fix Altera Cyclone ↵Thor Thayer
access When testing CAN write floods on Altera's CycloneV, the first 2 bytes are sometimes 0x00, 0x00 or corrupted instead of the values sent. Also observed bytes 4 & 5 were corrupted in some cases. The D_CAN Data registers are 32 bits and changing from 16 bit writes to 32 bit writes fixes the problem. Testing performed on Altera CycloneV (D_CAN). Requesting tests on other C_CAN & D_CAN platforms. Reported-by: Richard Andrysek <richard.andrysek@gomtec.de> Signed-off-by: Thor Thayer <tthayer@opensource.altera.com> Cc: <stable@vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2015-11-23can: remove obsolete assignment for CAN protocol error typeOliver Hartkopp
The assignment 'cf->data[2] |= CAN_ERR_PROT_UNSPEC' used at CAN error message creation time is obsolete as CAN_ERR_PROT_UNSPEC is zero and cf->data[2] is initialized with zero in alloc_can_err_skb() anyway. So we could either assign 'cf->data[2] = CAN_ERR_PROT_UNSPEC' correctly or we can remove the obsolete OR operation entirely. Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2015-11-23can: fix assignment of error location in CAN error messagesOliver Hartkopp
As Dan Carpenter reported in http://marc.info/?l=linux-can&m=144793696016187 the assignment of the error location in CAN error messages had some bit wise overlaps. Indeed the value to be assigned in data[3] is no bitfield but defines a single value which points to a location inside the CAN frame on the wire. This patch fixes the assignments for the error locations in error messages. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2015-07-12can: c_can: Fix default pinmux glitch at initJ.D. Schroeder
The previous change 3973c526ae9c (net: can: c_can: Disable pins when CAN interface is down) causes a slight glitch on the pinctrl settings when used. Since commit ab78029 (drivers/pinctrl: grab default handles from device core), the device core will automatically set the default pins. This causes the pins to be momentarily set to the default and then to the sleep state in register_c_can_dev(). By adding an optional "enable" state, boards can set the default pin state to be disabled and avoid the glitch when the switch from default to sleep first occurs. If the "enable" state is not available c_can_pinctrl_select_state() falls back to using the "default" pinctrl state. [Roger Q] - Forward port to v4.2 and use pinctrl_get_select(). Signed-off-by: J.D. Schroeder <jay.schroeder@garmin.com> Signed-off-by: Roger Quadros <rogerq@ti.com> Reviewed-by: Grygorii Strashko <grygorii.strashko@ti.com> Cc: linux-stable <stable@vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2015-01-27Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: arch/arm/boot/dts/imx6sx-sdb.dts net/sched/cls_bpf.c Two simple sets of overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-21can: c_can: end pending transmission on network stop (ifdown)Viktor Babrian
Put controller into init mode in network stop to end pending transmissions. The issue is observed in cases when transmitted frame is not acked. Signed-off-by: Viktor Babrian <babrian.viktor@renyi.mta.hu> Cc: linux-stable <stable@vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2015-01-20can: move can_stats.bus_off++ from can_bus_off into can_change_stateAndri Yngvason
In order to be able to move the stats increment from can_bus_off() into can_change_state(), the increment had to be moved back into code that was using can_bus_off() but not can_change_state(). As a side-effect, this patch fixes the following bugs: * Redundant call to can_bus_off() in c_can. * Bus-off counted twice in xilinx_can. Signed-off-by: Andri Yngvason <andri.yngvason@marel.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2015-01-15can: c_can: use regmap_update_bits() to modify RAMINIT registerRoger Quadros
use of regmap_read() and regmap_write() in c_can_hw_raminit_syscon() is not safe as the RAMINIT register can be shared between different drivers at least for TI SoCs. To make the modification atomic we switch to using regmap_update_bits(). regmap_update_bits() skips writing to the register if it's read content is the same as what is going to be written. This causes an issue for us when we need to clear the DONE bit with the initial condition START:0, DONE:1 as DONE bit must be written with 1 to clear it. So we defer the clearing of DONE bit to later when we set the START bit. There we are sure that START bit is changed from 0 to 1 so the write of 1 to already set DONE bit will happen. Signed-off-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-12-14Merge tag 'driver-core-3.19-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core update from Greg KH: "Here's the set of driver core patches for 3.19-rc1. They are dominated by the removal of the .owner field in platform drivers. They touch a lot of files, but they are "simple" changes, just removing a line in a structure. Other than that, a few minor driver core and debugfs changes. There are some ath9k patches coming in through this tree that have been acked by the wireless maintainers as they relied on the debugfs changes. Everything has been in linux-next for a while" * tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (324 commits) Revert "ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries" fs: debugfs: add forward declaration for struct device type firmware class: Deletion of an unnecessary check before the function call "vunmap" firmware loader: fix hung task warning dump devcoredump: provide a one-way disable function device: Add dev_<level>_once variants ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries ath: use seq_file api for ath9k debugfs files debugfs: add helper function to create device related seq_file drivers/base: cacheinfo: remove noisy error boot message Revert "core: platform: add warning if driver has no owner" drivers: base: support cpu cache information interface to userspace via sysfs drivers: base: add cpu_device_create to support per-cpu devices topology: replace custom attribute macros with standard DEVICE_ATTR* cpumask: factor out show_cpumap into separate helper function driver core: Fix unbalanced device reference in drivers_probe driver core: fix race with userland in device_add() sysfs/kernfs: make read requests on pre-alloc files use the buffer. sysfs/kernfs: allow attributes to request write buffer be pre-allocated. fs: sysfs: return EGBIG on write if offset is larger than file size ...
2014-11-17net: can: c_can: Add support for TI am4372 DCANRoger Quadros
AM4372 SoC has 2 DCAN modules. Add compatible id and raminit driver data for it. The driver data is same as AM3352 but this gives us flexibility to add AM4372 specific quirks if required later. Signed-off-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-11-17can: c_can: Add support for TI am3352 DCANRoger Quadros
AM3352 SoC has 2 DCAN modules. Add compatible id and raminit driver data for am3352 DCAN. Signed-off-by: Roger Quadros <rogerq@ti.com> Acked-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-11-17can: c_can: Add support for TI DRA7 DCANRoger Quadros
DRA7 SoC has 2 CAN IPs. Provide compatible IDs and RAMINIT register data for both. Signed-off-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-11-17can: c_can: Disable pins when CAN interface is downRoger Quadros
DRA7 CAN IP suffers from a problem which causes it to be prevented from fully turning OFF (i.e. stuck in transition) if the module was disabled while there was traffic on the CAN_RX line. To work around this issue we select the SLEEP pin state by default on probe and use the DEFAULT pin state on CAN up and back to the SLEEP pin state on CAN down. Signed-off-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-11-17can: c_can: Add support for START pulse in RAMINIT sequenceRoger Quadros
Some SoCs e.g. (TI DRA7xx) need a START pulse to start the RAMINIT sequence i.e. START bit must be set and cleared before checking for the DONE bit status. Signed-off-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-11-17can: c_can: Add syscon/regmap RAMINIT mechanismRoger Quadros
Some TI SoCs like DRA7 have a RAMINIT register specification different from the other AMxx SoCs and as expected by the existing driver. To add more insanity, this register is shared with other IPs like DSS, PCIe and PWM. Provides a more generic mechanism to specify the RAMINIT register location and START/DONE bit position and use the syscon/regmap framework to access the register. Signed-off-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-11-17can: c_can: Add RAMINIT register information to driver dataRoger Quadros
Some platforms (e.g. TI) need special RAMINIT register handling. Provide a way to store RAMINIT register description in driver data. Signed-off-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-11-17can: c_can: Introduce c_can_driver_data structureRoger Quadros
We want to have more data than just can_dev_id to be present in the driver data e.g. TI platforms need RAMINIT register description. Introduce the c_can_driver_data structure and move the can_dev_id into it. Tidy up the way it is used on probe(). Signed-off-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-11-17can: c_can: Add timeout to c_can_hw_raminit_ti()Roger Quadros
TI's RAMINIT DONE mechanism is buggy on AM43xx SoC and may not always be set after the START bit is set. Although it seems to work fine even in that case. So add a timeout mechanism to c_can_hw_raminit_wait_ti(). Don't bail out in that failure case but just print an error message. Signed-off-by: Roger Quadros <rogerq@ti.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-10-20net: can: c_can: drop owner assignment from platform_driversWolfram Sang
A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2014-09-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: arch/mips/net/bpf_jit.c drivers/net/can/flexcan.c Both the flexcan and MIPS bpf_jit conflicts were cases of simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-18can: c_can_platform: fix parameters of c_can_hw_raminit_ti()Roger Quadros
Pass the correct 'mask' and 'value' bits to c_can_hw_raminit_wait_ti(). They seem to have been swapped in the usage instances. Reported-by: Jay Schroeder <jay.schroeder@garmin.com> Signed-off-by: Roger Quadros <rogerq@ti.com> Cc: linux-stable <stable@vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-08-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Pulling to get some TIPC fixes that a net-next series depends upon. Signed-off-by: David S. Miller <davem@davemloft.net>
2014-08-21can: c_can: checking IS_ERR() instead of NULLDan Carpenter
devm_ioremap() returns NULL on error, not an ERR_PTR(). Fixes: 33cf75656923 ('can: c_can_platform: Fix raminit, use devm_ioremap() instead of devm_ioremap_resource()') Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: linux-stable <stable@vger.kernel.org> # >= v3.11 Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-08-18net: can: use kbuild magic to inherit debug settingsWolfram Sang
No need to manually copy debug settings into subdir Makefiles. kbuild has a mechanism for inheriting, so let's use it. Signed-off-by: Wolfram Sang <wsa@the-dreams.de> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-08-12PCI: Remove DEFINE_PCI_DEVICE_TABLE macro useBenoit Taine
We should prefer `struct pci_device_id` over `DEFINE_PCI_DEVICE_TABLE` to meet kernel coding style guidelines. This issue was reported by checkpatch. A simplified version of the semantic patch that makes this change is as follows (http://coccinelle.lip6.fr/): // <smpl> @@ identifier i; declarer name DEFINE_PCI_DEVICE_TABLE; initializer z; @@ - DEFINE_PCI_DEVICE_TABLE(i) + const struct pci_device_id i[] = z; // </smpl> [bhelgaas: add semantic patch] Signed-off-by: Benoit Taine <benoit.taine@lip6.fr> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
2014-07-30Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-25can: c_can_platform: Fix raminit, use devm_ioremap() instead of ↵George Cherian
devm_ioremap_resource() The raminit register is shared register for both can0 and can1. Since commit: 32766ff net: can: Convert to use devm_ioremap_resource devm_ioremap_resource() is used to map raminit register. When using both interfaces the mapping for the can1 interface fails, leading to a non functional can interface. Signed-off-by: George Cherian <george.cherian@ti.com> Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com> Cc: linux-stable <stable@vger.kernel.org> # >= v3.11 Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-07-15can: c_can: convert to use devm * apiLad, Prabhakar
This patch uses devm_* APIs as they are device managed and make code simpler. Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
2014-05-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
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>
2014-05-19can: c_can: add hwinit support for non-TI devicesPavel Machek
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>
2014-05-19can: c_can: Add and make use of 32-bit accesses functionsPavel Machek
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>
2014-05-19can: c_can: make {read,write}_reg functions constPavel Machek
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>
2014-05-19can: c_can: remove obsolete STRICT_FRAME_ORDERING Kconfig optionOliver Hartkopp
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>
2014-05-12Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
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>
2014-04-25can: c_can: Add support for eg20t (pch_can)Alexander Stein
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>
2014-04-24can: c_can_pci: enable PCI bus master only for MSIWolfgang Grandegger
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>
2014-04-24can: c_can: use proper type for 'instance'Wolfram Sang
Commit 6439fbce1075 (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>
2014-04-24can: c_can: Speed up tx buffer invalidationThomas Gleixner
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>
2014-04-24can: c_can: Remove tx lockingThomas Gleixner
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>
2014-04-24can: c_can: Use proper u32 variables in c_can_write_msg_object()Thomas Gleixner
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>
2014-04-24can: c_can: Cleanup c_can_write_msg_object()Thomas Gleixner
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>
2014-04-24can: c_can: Cleanup c_can_msg_obj_put/get()Thomas Gleixner
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>
2014-04-24can: c_can: Cleanup c_can_inval_msg_object()Thomas Gleixner
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>
2014-04-24can: c_can: Cleanup setup of receive buffersThomas Gleixner
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>
2014-04-24can: c_can: Cleanup c_can_read_msg_object()Thomas Gleixner
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>
2014-04-24can: c_can: Cleanup irq enable/disableThomas Gleixner
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>
2014-04-24can: c_can: Work around C_CAN RX wreckageThomas Gleixner
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>
2014-04-24can: c_can: Disable rx split as workaroundThomas Gleixner
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>