Move the nfp_net_get_port_mac_by_hwinfo() check to ahead in the
get/set_eeprom() functions to in order to check for a VF netdev, which
this function does not support.
It is debatable if this is a fix or an enhancement, and we have chosen
to go for the latter. It does address a problem introduced by
commit 74b4f1739d ("nfp: flower: change get/set_eeprom logic and enable for flower reps").
However, the ethtool->len == 0 check avoids the problem manifesting as a
run-time bug (NULL pointer dereference of app).
Signed-off-by: James Hershaw <james.hershaw@corigine.com>
Reviewed-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20230206154836.2803995-1-simon.horman@corigine.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Petr Machata says:
====================
mlxsw: Misc devlink changes
This patchset adjusts mlxsw to recent devlink changes in net-next.
Patch #1 removes a devl_param_driverinit_value_set() call that was
unnecessary, but now additionally triggers a WARN_ON.
Patches #2-#4 are non-functional preparations for the following patches.
Patch #5 fixes a use-after-free that is triggered while changing network
namespaces.
Patch #6 makes mlxsw consistent with netdevsim by having mlxsw register
its devlink instance before its sub-objects. It helps us avoid a warning
described in the commit message.
====================
Link: https://lore.kernel.org/r/cover.1675692666.git.petrm@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Recent changes made it possible to register the devlink instance before
its sub-objects and under the instance lock. Among other things, it
allows us to avoid warnings such as this one [1]. The warning is
generated because a buggy firmware is generating a health event during
driver initialization, before the devlink instance is registered.
Move the registration of the devlink instance to the beginning of the
initialization flow to avoid such problems.
A similar change was implemented in netdevsim in commit 82a3aef2e6
("netdevsim: move devlink registration under the instance lock").
[1]
WARNING: CPU: 3 PID: 49 at net/devlink/leftover.c:7509 devlink_recover_notify.constprop.0+0xaf/0xc0
[...]
Call Trace:
<TASK>
devlink_health_report+0x45/0x1d0
mlxsw_core_health_event_work+0x24/0x30 [mlxsw_core]
process_one_work+0x1db/0x390
worker_thread+0x49/0x3b0
kthread+0xe5/0x110
ret_from_fork+0x1f/0x30
</TASK>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Cited commit added 'DEVLINK_CMD_PARAM_DEL' notifications whenever the
network namespace of the devlink instance is changed. Specifically, the
notifications are generated after calling reload_down(), but before
calling reload_up(). At this stage, the data structures accessed while
reading the value of the "acl_region_rehash_interval" devlink parameter
are uninitialized, resulting in a use-after-free [1].
Fix by moving the registration and unregistration of the devlink
parameter to the TCAM code where it is actually used. This means that
the parameter is unregistered during reload_down() and then
re-registered during reload_up(), avoiding the use-after-free between
these two operations.
Reproducer:
# ip netns add test123
# devlink dev reload pci/0000:06:00.0 netns test123
[1]
BUG: KASAN: use-after-free in mlxsw_sp_acl_tcam_vregion_rehash_intrvl_get+0xb2/0xd0
Read of size 4 at addr ffff888162fd37d8 by task devlink/1323
[...]
Call Trace:
<TASK>
dump_stack_lvl+0x95/0xbd
print_report+0x181/0x4a1
kasan_report+0xdb/0x200
mlxsw_sp_acl_tcam_vregion_rehash_intrvl_get+0xb2/0xd0
mlxsw_sp_params_acl_region_rehash_intrvl_get+0x32/0x80
devlink_nl_param_fill.constprop.0+0x29a/0x11e0
devlink_param_notify.constprop.0+0xb9/0x250
devlink_notify_unregister+0xbc/0x470
devlink_reload+0x1aa/0x440
devlink_nl_cmd_reload+0x559/0x11b0
genl_family_rcv_msg_doit.isra.0+0x1f8/0x2e0
genl_rcv_msg+0x558/0x7f0
netlink_rcv_skb+0x170/0x440
genl_rcv+0x2d/0x40
netlink_unicast+0x53f/0x810
netlink_sendmsg+0x961/0xe80
__sys_sendto+0x2a4/0x420
__x64_sys_sendto+0xe5/0x1c0
do_syscall_64+0x38/0x80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Fixes: 7d7e9169a3 ("devlink: move devlink reload notifications back in between _down() and _up() calls")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Move the initialization and de-initialization code further below in
order to avoid forward declarations in the next patch. No functional
changes.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Move mutex_destroy() to the end to make the function symmetric with
mlxsw_sp_acl_tcam_init(). No functional changes.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The "acl_region_rehash_interval" devlink parameter is a "runtime"
parameter, making the call to devl_param_driverinit_value_set()
pointless. Before cited commit the function simply returned an error
(that was not checked), but now it emits a WARNING [1].
Fix by removing the function call.
[1]
WARNING: CPU: 0 PID: 7 at net/devlink/leftover.c:10974
devl_param_driverinit_value_set+0x8c/0x90
[...]
Call Trace:
<TASK>
mlxsw_sp2_params_register+0x83/0xb0 [mlxsw_spectrum]
__mlxsw_core_bus_device_register+0x5e5/0x990 [mlxsw_core]
mlxsw_core_bus_device_register+0x42/0x60 [mlxsw_core]
mlxsw_pci_probe+0x1f0/0x230 [mlxsw_pci]
local_pci_probe+0x1a/0x40
work_for_cpu_fn+0xf/0x20
process_one_work+0x1db/0x390
worker_thread+0x1d5/0x3b0
kthread+0xe5/0x110
ret_from_fork+0x1f/0x30
</TASK>
Fixes: 85fe0b324c ("devlink: make devlink_param_driverinit_value_set() return void")
Signed-off-by: Danielle Ratson <danieller@nvidia.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Yury Norov says:
====================
sched: cpumask: improve on cpumask_local_spread() locality
cpumask_local_spread() currently checks local node for presence of i'th
CPU, and then if it finds nothing makes a flat search among all non-local
CPUs. We can do it better by checking CPUs per NUMA hops.
This has significant performance implications on NUMA machines, for example
when using NUMA-aware allocated memory together with NUMA-aware IRQ
affinity hints.
Performance tests from patch 8 of this series for mellanox network
driver show:
TCP multi-stream, using 16 iperf3 instances pinned to 16 cores (with aRFS on).
Active cores: 64,65,72,73,80,81,88,89,96,97,104,105,112,113,120,121
+-------------------------+-----------+------------------+------------------+
| | BW (Gbps) | TX side CPU util | RX side CPU util |
+-------------------------+-----------+------------------+------------------+
| Baseline | 52.3 | 6.4 % | 17.9 % |
+-------------------------+-----------+------------------+------------------+
| Applied on TX side only | 52.6 | 5.2 % | 18.5 % |
+-------------------------+-----------+------------------+------------------+
| Applied on RX side only | 94.9 | 11.9 % | 27.2 % |
+-------------------------+-----------+------------------+------------------+
| Applied on both sides | 95.1 | 8.4 % | 27.3 % |
+-------------------------+-----------+------------------+------------------+
Bottleneck in RX side is released, reached linerate (~1.8x speedup).
~30% less cpu util on TX.
====================
Link: https://lore.kernel.org/r/20230121042436.2661843-1-yury.norov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Now that we have an iterator-based alternative for a very common case
of using cpumask_local_spread for all cpus in a row, it's worth to
mention that in comment to cpumask_local_spread().
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The recently introduced sched_numa_hop_mask() exposes cpumasks of CPUs
reachable within a given distance budget, wrap the logic for iterating over
all (distance, mask) values inside an iterator macro.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Tariq has pointed out that drivers allocating IRQ vectors would benefit
from having smarter NUMA-awareness - cpumask_local_spread() only knows
about the local node and everything outside is in the same bucket.
sched_domains_numa_masks is pretty much what we want to hand out (a cpumask
of CPUs reachable within a given distance budget), introduce
sched_numa_hop_mask() to export those cpumasks.
Link: http://lore.kernel.org/r/20220728191203.4055-1-tariqt@nvidia.com
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Now after moving all NUMA logic into sched_numa_find_nth_cpu(),
else-branch of cpumask_local_spread() is just a function call, and
we can simplify logic by using ternary operator.
While here, replace BUG() with WARN_ON().
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Peter Lafreniere <peter@n8pjl.ca>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The function finds Nth set CPU in a given cpumask starting from a given
node.
Leveraging the fact that each hop in sched_domains_numa_masks includes the
same or greater number of CPUs than the previous one, we can use binary
search on hops instead of linear walk, which makes the overall complexity
of O(log n) in terms of number of cpumask_weight() calls.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Peter Lafreniere <peter@n8pjl.ca>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Introduce cpumask_nth_and_andnot() based on find_nth_and_andnot_bit().
It's used in the following patch to traverse cpumasks without storing
intermediate result in temporary cpumask.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Peter Lafreniere <peter@n8pjl.ca>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
In the following patches the function is used to implement in-place bitmaps
traversing without storing intermediate result in temporary bitmaps.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Tariq Toukan <tariqt@nvidia.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Peter Lafreniere <peter@n8pjl.ca>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Eric Dumazet says:
====================
net: core: use a dedicated kmem_cache for skb head allocs
Our profile data show that using kmalloc(non_const_size)/kfree(ptr)
has a certain cost, because kfree(ptr) has to pull a 'struct page'
in cpu caches.
Using a dedicated kmem_cache for TCP skb->head allocations makes
a difference, both in cpu cycles and memory savings.
This kmem_cache could also be used for GRO skb allocations,
this is left as a future exercise.
====================
Link: https://lore.kernel.org/r/20230206173103.2617121-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Recent removal of ksize() in alloc_skb() increased
performance because we no longer read
the associated struct page.
We have an equivalent cost at kfree_skb() time.
kfree(skb->head) has to access a struct page,
often cold in cpu caches to get the owning
struct kmem_cache.
Considering that many allocations are small (at least for TCP ones)
we can have our own kmem_cache to avoid the cache line miss.
This also saves memory because these small heads
are no longer padded to 1024 bytes.
CONFIG_SLUB=y
$ grep skbuff_small_head /proc/slabinfo
skbuff_small_head 2907 2907 640 51 8 : tunables 0 0 0 : slabdata 57 57 0
CONFIG_SLAB=y
$ grep skbuff_small_head /proc/slabinfo
skbuff_small_head 607 624 640 6 1 : tunables 54 27 8 : slabdata 104 104 5
Notes:
- After Kees Cook patches and this one, we might
be able to revert commit
dbae2b0628 ("net: skb: introduce and use a single page frag cache")
because GRO_MAX_HEAD is also small.
- This patch is a NOP for CONFIG_SLOB=y builds.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
All kmalloc_reserve() callers have to make the same computation,
we can factorize them, to prepare following patch in the series.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We have many places using this expression:
SKB_DATA_ALIGN(sizeof(struct skb_shared_info))
Use of SKB_HEAD_ALIGN() will allow to clean them.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Marc Kleine-Budde says:
====================
pull-request: can-next 2023-02-06
this is a pull request of 47 patches for net-next/master.
The first two patch is by Oliver Hartkopp. One adds missing error
checking to the CAN_GW protocol, the other adds a missing CAN address
family check to the CAN ISO TP protocol.
Thomas Kopp contributes a performance optimization to the mcp251xfd
driver.
The next 11 patches are by Geert Uytterhoeven and add support for
R-Car V4H systems to the rcar_canfd driver.
Stephane Grosjean and Lukas Magel contribute 8 patches to the peak_usb
driver, which add support for configurable CAN channel ID.
The last 17 patches are by me and target the CAN bit timing
configuration. The bit timing is cleaned up, error messages are
improved and forwarded to user space via NL_SET_ERR_MSG_FMT() instead
of netdev_err(), and the SJW handling is updated, including the
definition of a new default value that will benefit CAN-FD
controllers, by increasing their oscillator tolerance.
* tag 'linux-can-next-for-6.3-20230206' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next: (47 commits)
can: bittiming: can_validate_bitrate(): report error via netlink
can: bittiming: can_calc_bittiming(): convert from netdev_err() to NL_SET_ERR_MSG_FMT()
can: bittiming: can_calc_bittiming(): clean up SJW handling
can: bittiming: can_sjw_set_default(): use Phase Seg2 / 2 as default for SJW
can: bittiming: can_sjw_check(): check that SJW is not longer than either Phase Buffer Segment
can: bittiming: can_sjw_check(): report error via netlink and harmonize error value
can: bittiming: can_fixup_bittiming(): report error via netlink and harmonize error value
can: bittiming: factor out can_sjw_set_default() and can_sjw_check()
can: bittiming: can_changelink() pass extack down callstack
can: netlink: can_changelink(): convert from netdev_err() to NL_SET_ERR_MSG_FMT()
can: netlink: can_validate(): validate sample point for CAN and CAN-FD
can: dev: register_candev(): bail out if both fixed bit rates and bit timing constants are provided
can: dev: register_candev(): ensure that bittiming const are valid
can: bittiming: can_get_bittiming(): use direct return and remove unneeded else
can: bittiming: can_fixup_bittiming(): set effective tq
can: bittiming: can_fixup_bittiming(): use CAN_SYNC_SEG instead of 1
can: bittiming(): replace open coded variants of can_bit_time()
can: peak_usb: Reorder include directives alphabetically
can: peak_usb: align CAN channel ID format in log with sysfs attribute
can: peak_usb: export PCAN CAN channel ID as sysfs device attribute
...
====================
Link: https://lore.kernel.org/r/20230206131620.2758724-1-mkl@pengutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Use actual CPU number instead of hardcoded value to decide the size
of 'cpu_used_mask' in 'struct sw_flow'. Below is the reason.
'struct cpumask cpu_used_mask' is embedded in struct sw_flow.
Its size is hardcoded to CONFIG_NR_CPUS bits, which can be
8192 by default, it costs memory and slows down ovs_flow_alloc.
To address this:
Redefine cpu_used_mask to pointer.
Append cpumask_size() bytes after 'stat' to hold cpumask.
Initialization cpu_used_mask right after stats_last_writer.
APIs like cpumask_next and cpumask_set_cpu never access bits
beyond cpu count, cpumask_size() bytes of memory is enough.
Signed-off-by: Eddy Tao <taoyuan_eddy@hotmail.com>
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Link: https://lore.kernel.org/r/OS3P286MB229570CCED618B20355D227AF5D59@OS3P286MB2295.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The forward declaration was introduced with a prototype that does
not match the function definition:
drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c:2166:13: error: conflicting types for 'xgbe_phy_perform_ratechange' due to enum/integer mismatch; have 'void(struct xgbe_prv_data *, enum xgbe_mb_cmd, enum xgbe_mb_subcmd)' [-Werror=enum-int-mismatch]
2166 | static void xgbe_phy_perform_ratechange(struct xgbe_prv_data *pdata,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/amd/xgbe/xgbe-phy-v2.c:391:13: note: previous declaration of 'xgbe_phy_perform_ratechange' with type 'void(struct xgbe_prv_data *, unsigned int, unsigned int)'
391 | static void xgbe_phy_perform_ratechange(struct xgbe_prv_data *pdata,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
Ideally there should not be any forward declarations here, which
would make it easier to show that there is no unbounded recursion.
I tried fixing this but could not figure out how to avoid the
recursive call.
As a hotfix, address only the broken prototype to fix the build
problem instead.
Fixes: 4f3b20bfbb ("amd-xgbe: add support for rx-adaptation")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Acked-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Link: https://lore.kernel.org/r/20230203121553.2871598-1-arnd@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Ajit Khaparde says:
====================
bnxt: Add Auxiliary driver support
Add auxiliary device driver for Broadcom devices.
The bnxt_en driver will register and initialize an aux device
if RDMA is enabled in the underlying device.
The bnxt_re driver will then probe and initialize the
RoCE interfaces with the infiniband stack.
We got rid of the bnxt_en_ops which the bnxt_re driver used to
communicate with bnxt_en.
Similarly We have tried to clean up most of the bnxt_ulp_ops.
In most of the cases we used the functions and entry points provided
by the auxiliary bus driver framework.
And now these are the minimal functions needed to support the functionality.
We will try to work on getting rid of the remaining if we find any
other viable option in future.
* 'aux-bus-v11' of https://github.com/ajitkhaparde1/linux:
bnxt_en: Remove runtime interrupt vector allocation
RDMA/bnxt_re: Remove the sriov config callback
bnxt_en: Remove struct bnxt access from RoCE driver
bnxt_en: Use auxiliary bus calls over proprietary calls
bnxt_en: Use direct API instead of indirection
bnxt_en: Remove usage of ulp_id
RDMA/bnxt_re: Use auxiliary driver interface
bnxt_en: Add auxiliary driver support
====================
Link: https://lore.kernel.org/r/20230202033809.3989-1-ajit.khaparde@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Marc Kleine-Budde <mkl@pengutronix.de> says:
several people noticed that on modern CAN controllers with wide bit
timing registers the default SJW of 1 can result in unstable or no
synchronization to the CAN network. See Patch 14/17 for details.
During review of v1 Vincent pointed out that the original code and the
series doesn't always check user provided bit timing parameters,
sometimes silently limits them and the return error values are not
consistent.
This series first cleans up some code in bittiming.c, replacing
open-coded variants by macros or functions (Patches 1, 2).
Patch 3 adds the missing assignment of the effective TQ if the
interface is configured with low level timing parameters.
Patch 4 is another code cleanup.
Patches 5, 6 check the bit timing parameter during interface
registration.
Patch 7 adds a validation of the sample point.
The patches 8-13 convert the error messages from netdev_err() to
NL_SET_ERR_MSG_FMT, factor out the SJW handling from
can_fixup_bittiming(), add checking and error messages for the
individual limits and harmonize the error return values.
Patch 14 changes the default SJW value from 1 to min(Phase Seg1, Phase
Seg2 / 2).
Patch 15 switches can_calc_bittiming() to use the new SJW handling.
Patch 16 converts can_calc_bittiming() to NL_SET_ERR_MSG_FMT().
And patch 16 adds a NL_SET_ERR_MSG_FMT() error message to
can_validate_bitrate().
v1: https://lore.kernel.org/all/20220907103845.3929288-1-mkl@pengutronix.de
Link: https://lore.kernel.org/all/20230202110854.2318594-1-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Replace the netdev_err() by NL_SET_ERR_MSG_FMT() to better inform the
user about the problem. While there, use %u to print unsigned values
and improve error message a bit.
In case of an error, return -EINVAL instead of -EDOM, this corresponds
better to the actual meaning of the error value.
Link: https://lore.kernel.org/all/20230202110854.2318594-17-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
"The (Re-)Synchronization Jump Width (SJW) defines how far a
resynchronization may move the Sample Point inside the limits defined
by the Phase Buffer Segments to compensate for edge phase errors." [1]
In other words, this means that the SJW parameter controls the
tolerance of the CAN controller to frequency errors compared to other
CAN controllers.
If the user space does not provide an SJW parameter, the kernel
chooses a default value of 1. This has proven to be a good default
value for classic CAN controllers, but no longer for modern CAN-FD
controllers.
In the past there were CAN controllers like the sja1000 with a rather
limited range of bit timing parameters. For the standard bit rates
this results in the following bit timing parameters:
| Bit timing parameters for sja1000 with 8.000000 MHz ref clock
| _----+--------------=> tseg1: 1 … 16
| / / _---------=> tseg2: 1 … 8
| | | / _-----=> sjw: 1 … 4
| | | | / _-=> brp: 1 … 64 (inc: 1)
| | | | | /
| nominal | | | | | real Bitrt nom real SampP
| Bitrate TQ[ns] PrS PhS1 PhS2 SJW BRP Bitrate Error SampP SampP Error BTR0 BTR1
| 1000000 125 2 3 2 1 1 1000000 0.0% 75.0% 75.0% 0.0% 0x00 0x14
| 800000 125 3 4 2 1 1 800000 0.0% 80.0% 80.0% 0.0% 0x00 0x16
| 666666 125 4 4 3 1 1 666666 0.0% 80.0% 75.0% 6.2% 0x00 0x27
| 500000 125 6 7 2 1 1 500000 0.0% 87.5% 87.5% 0.0% 0x00 0x1c
| 250000 250 6 7 2 1 2 250000 0.0% 87.5% 87.5% 0.0% 0x01 0x1c
| 125000 500 6 7 2 1 4 125000 0.0% 87.5% 87.5% 0.0% 0x03 0x1c
| 100000 625 6 7 2 1 5 100000 0.0% 87.5% 87.5% 0.0% 0x04 0x1c
| 83333 750 6 7 2 1 6 83333 0.0% 87.5% 87.5% 0.0% 0x05 0x1c
| 50000 1250 6 7 2 1 10 50000 0.0% 87.5% 87.5% 0.0% 0x09 0x1c
| 33333 1875 6 7 2 1 15 33333 0.0% 87.5% 87.5% 0.0% 0x0e 0x1c
| 20000 3125 6 7 2 1 25 20000 0.0% 87.5% 87.5% 0.0% 0x18 0x1c
| 10000 6250 6 7 2 1 50 10000 0.0% 87.5% 87.5% 0.0% 0x31 0x1c
The attentive reader will notice that the SJW is 1 in most cases,
while the Seg2 phase is 2. Both values are given in TQ units, which in
turn is a duration in nanoseconds.
For example the 500 kbit/s configuration:
| nominal real Bitrt nom real SampP
| Bitrate TQ[ns] PrS PhS1 PhS2 SJW BRP Bitrate Error SampP SampP Error BTR0 BTR1
| 500000 125 6 7 2 1 1 500000 0.0% 87.5% 87.5% 0.0% 0x00 0x1c
the TQ is 125ns, the Phase Seg2 is "2" (== 250ns), the SJW is "1" (==
125 ns).
Looking at a more modern CAN controller like a mcp2518fd, it has wider
bit timing registers.
| Bit timing parameters for mcp251xfd with 40.000000 MHz ref clock
| _----+--------------=> tseg1: 2 … 256
| / / _---------=> tseg2: 1 … 128
| | | / _-----=> sjw: 1 … 128
| | | | / _-=> brp: 1 … 256 (inc: 1)
| | | | | /
| nominal | | | | | real Bitrt nom real SampP
| Bitrate TQ[ns] PrS PhS1 PhS2 SJW BRP Bitrate Error SampP SampP Error NBTCFG
| 500000 25 34 35 10 1 1 500000 0.0% 87.5% 87.5% 0.0% 0x00440900
The TQ is 25ns, the Phase Seg 2 is "10" (== 250ns), the SJW is "1" (==
25ns).
Since the kernel chooses a default SJW of 1 regardless of the TQ, this
leads to a much smaller SJW and thus much smaller tolerances to
frequency errors.
To maintain the same oscillator tolerances on controllers with wide
bit timing registers, select a default SJW value of Phase Seg2 / 2
unless Phase Seg 1 is less. This results in the following bit timing
parameters:
| Bit timing parameters for mcp251xfd with 40.000000 MHz ref clock
| _----+--------------=> tseg1: 2 … 256
| / / _---------=> tseg2: 1 … 128
| | | / _-----=> sjw: 1 … 128
| | | | / _-=> brp: 1 … 256 (inc: 1)
| | | | | /
| nominal | | | | | real Bitrt nom real SampP
| Bitrate TQ[ns] PrS PhS1 PhS2 SJW BRP Bitrate Error SampP SampP Error NBTCFG
| 500000 25 34 35 10 5 1 500000 0.0% 87.5% 87.5% 0.0% 0x00440904
The TQ is 25ns, the Phase Seg 2 is "10" (== 250ns), the SJW is "5" (==
125ns). Which is the same as on the sja1000 controller.
[1] http://web.archive.org/http://www.oertel-halle.de/files/cia99paper.pdf
Link: https://lore.kernel.org/all/20230202110854.2318594-15-mkl@pengutronix.de
Cc: Mark Bath <mark@baggywrinkle.co.uk>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
If the user space has supplied an invalid SJW value (greater than the
maximum SJW value), report -EINVAL instead of -ERANGE, this better
matches the actual meaning of the error value.
Additionally report an error message via netlink to the user space.
Link: https://lore.kernel.org/all/20230202110854.2318594-13-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Factor out the functionality of assigning a SJW default value into
can_sjw_set_default() and the checking the SJW limits into
can_sjw_check().
This functions will be improved and called from a different function
in the following patches.
Link: https://lore.kernel.org/all/20230202110854.2318594-11-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This is a preparation patch.
In order to pass warning/error messages during netlink calls back to
user space, pass the extack struct down the callstack of
can_changelink(), the actual error messages will be added in the
following ptaches.
Link: https://lore.kernel.org/all/20230202110854.2318594-10-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Since commit 51c352bdbc ("netlink: add support for formatted extack
messages") formatted extack messages are supported to inform the user
space or warnings/errors during netlink calls.
Replace the netdev_err() by NL_SET_ERR_MSG_FMT() to better inform the
user about the problem. While there, use %u to print unsigned values
and improve error message a bit.
Link: https://lore.kernel.org/all/20230202110854.2318594-9-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Implement the function can_bittiming_const_valid() to check the
validity of the specified bit timing constant. Call this function from
register_candev() to check the bit timing constants during the
registration of the CAN interface.
Link: https://lore.kernel.org/all/20230202110854.2318594-6-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
The can_fixup_bittiming() function is used to validate the
user-supplied low-level bit timing parameters and calculate the
bitrate prescaler (brp) from the requested time quanta (tq) and the
CAN clock of the controller.
can_fixup_bittiming() selects the best matching integer bit rate
prescaler, which may result in a different time quantum than the value
specified by the user.
Calculate the resulting time quantum and assign it so that the user
sees the effective time quantum.
Link: https://lore.kernel.org/all/20230202110854.2318594-4-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Commit 1c47fa6b31 ("can: dev: add a helper function to calculate the
duration of one bit") made the constant CAN_SYNC_SEG available in a
header file.
The magic number 1 in can_fixup_bittiming() represents the width of
the sync segment, replace it by CAN_SYNC_SEG to make the code more
readable.
Link: https://lore.kernel.org/all/20230202110854.2318594-3-mkl@pengutronix.de
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
