* [PATCH v1 1/5] can: add new CAN FD bittiming parameters: Transmitter Delay Compensation (TDC)
2021-02-23 16:28 [PATCH v1 0/5] Introducing new CAN FD bittiming parameters: Transmission Delay Compensation (TDC) Vincent Mailhol
@ 2021-02-23 16:28 ` Vincent Mailhol
2021-02-23 16:28 ` [PATCH v1 2/5] can: dev: reorder struct can_priv members for better packing Vincent Mailhol
` (3 subsequent siblings)
4 siblings, 0 replies; 11+ messages in thread
From: Vincent Mailhol @ 2021-02-23 16:28 UTC (permalink / raw)
To: Marc Kleine-Budde, linux-can, Oliver Hartkopp
Cc: Wolfgang Grandegger, Vincent Mailhol
At high bit rates, the propagation delay from the TX pin to the RX pin
of the transceiver causes measurement errors: the sample point on the
RX pin might occur on the previous bit.
This issue is addressed in ISO 11898-1 section 11.3.3 "Transmitter
delay compensation" (TDC).
This patch adds two new structures: can_tdc and can_tdc_const in order
to implement this TDC.
The structures are then added to can_priv.
A controller supports TDC if an only if can_priv::tdc_const is not
NULL. TDC is active if and only if can_priv::tdc.tdco is not zero. No
new controller modes are introduced (i.e. no CAN_CTRL_MODE_TDC) in
order not to be redundant with above logic.
The names of the parameters are chosen to match existing CAN
controllers specification. References:
- Bosch C_CAN FD8:
https://www.bosch-semiconductors.com/media/ip_modules/pdf_2/c_can_fd8/users_manual_c_can_fd8_r210_1.pdf
- Microchip CAN FD Controller Module:
http://ww1.microchip.com/downloads/en/DeviceDoc/MCP251XXFD-CAN-FD-Controller-Module-Family-Reference-Manual-20005678B.pdf
- SAM E701/S70/V70/V71 Family:
https://www.mouser.com/datasheet/2/268/60001527A-1284321.pdf
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
include/linux/can/bittiming.h | 65 +++++++++++++++++++++++++++++++++++
include/linux/can/dev.h | 3 ++
2 files changed, 68 insertions(+)
diff --git a/include/linux/can/bittiming.h b/include/linux/can/bittiming.h
index 707575c668f4..91bf9f8926a7 100644
--- a/include/linux/can/bittiming.h
+++ b/include/linux/can/bittiming.h
@@ -1,5 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0-only */
/* Copyright (c) 2020 Pengutronix, Marc Kleine-Budde <kernel@pengutronix.de>
+ * Copyright (c) 2021 Vincent Mailhol <mailhol.vincent@wanadoo.fr>
*/
#ifndef _CAN_BITTIMING_H
@@ -10,6 +11,70 @@
#define CAN_SYNC_SEG 1
+/*
+ * struct can_tdc - CAN FD Transmission Delay Compensation parameters
+ *
+ * At high bit rates, the propagation delay from the TX pin to the RX
+ * pin of the transceiver causes measurement errors: the sample point
+ * on the RX pin might occur on the previous bit.
+ *
+ * To solve this issue, ISO 11898-1 introduces in section 11.3.3
+ * "Transmitter delay compensation" a SSP (Secondary Sample Point)
+ * equal to the distance, in time quanta, from the start of the bit
+ * time on the TX pin to the actual measurement on the RX pin.
+ *
+ * This structure contains the parameters to calculate that SSP.
+ *
+ * @tdcv: Transmitter Delay Compensation Value. Distance, in time
+ * quanta, from when the bit is sent on the TX pin to when it is
+ * received on the RX pin of the transmitter. Possible options:
+ *
+ * O: automatic mode. The controller dynamically measure @tdcv
+ * for each transmited CAN FD frame.
+ *
+ * Other values: manual mode. Use the fixed provided value.
+ *
+ * @tdco: Transmitter Delay Compensation Offset. Offset value, in time
+ * quanta, defining the distance between the start of the bit
+ * reception on the RX pin of the transceiver and the SSP
+ * position such as SSP = @tdcv + @tdco.
+ *
+ * If @tdco is zero, then TDC is disabled and both @tdcv and
+ * @tdcf should be ignored.
+ *
+ * @tdcf: Transmitter Delay Compensation Filter window. Defines the
+ * minimum value for the SSP position in time quanta. If SSP is
+ * less than @tdcf, then no delay compensations occur and the
+ * normal sampling point is used instead. The feature is enabled
+ * if and only if @tdcv is set to zero (automatic mode) and @tdcf
+ * is configured to a value greater than @tdco.
+ */
+struct can_tdc {
+ u32 tdcv;
+ u32 tdco;
+ u32 tdcf;
+};
+
+/*
+ * struct can_tdc_const - CAN hardware-dependent constant for
+ * Transmission Delay Compensation
+ *
+ * @tdcv_max: Transmitter Delay Compensation Value maximum value.
+ * Should be set to zero if the controller does not support
+ * manual mode for tdcv.
+ * @tdco_max: Transmitter Delay Compensation Offset maximum value.
+ * Should not be zero. If the controller does not support TDC,
+ * then the pointer to this structure should be NULL.
+ * @tdcf_max: Transmitter Delay Compensation Filter window maximum
+ * value. Should be set to zero if the controller does not
+ * support this feature.
+ */
+struct can_tdc_const {
+ u32 tdcv_max;
+ u32 tdco_max;
+ u32 tdcf_max;
+};
+
#ifdef CONFIG_CAN_CALC_BITTIMING
int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
const struct can_bittiming_const *btc);
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index ac4d83a1ab81..4795da0eb949 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -42,6 +42,9 @@ struct can_priv {
struct can_bittiming bittiming, data_bittiming;
const struct can_bittiming_const *bittiming_const,
*data_bittiming_const;
+ struct can_tdc tdc;
+ const struct can_tdc_const *tdc_const;
+
const u16 *termination_const;
unsigned int termination_const_cnt;
u16 termination;
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v1 2/5] can: dev: reorder struct can_priv members for better packing
2021-02-23 16:28 [PATCH v1 0/5] Introducing new CAN FD bittiming parameters: Transmission Delay Compensation (TDC) Vincent Mailhol
2021-02-23 16:28 ` [PATCH v1 1/5] can: add new CAN FD bittiming parameters: Transmitter " Vincent Mailhol
@ 2021-02-23 16:28 ` Vincent Mailhol
2021-02-23 16:28 ` [PATCH v1 3/5] can: netlink: move '=' operators back to previous line (checkpatch fix) Vincent Mailhol
` (2 subsequent siblings)
4 siblings, 0 replies; 11+ messages in thread
From: Vincent Mailhol @ 2021-02-23 16:28 UTC (permalink / raw)
To: Marc Kleine-Budde, linux-can, Oliver Hartkopp
Cc: Wolfgang Grandegger, Vincent Mailhol
Save eight bytes of holes on x86-64 architectures by reordering struct
can_priv members.
Before:
$ pahole -C can_priv drivers/net/can/dev/dev.o
struct can_priv {
struct net_device * dev; /* 0 8 */
struct can_device_stats can_stats; /* 8 24 */
struct can_bittiming bittiming; /* 32 32 */
/* --- cacheline 1 boundary (64 bytes) --- */
struct can_bittiming data_bittiming; /* 64 32 */
const struct can_bittiming_const * bittiming_const; /* 96 8 */
const struct can_bittiming_const * data_bittiming_const; /* 104 8 */
struct can_tdc tdc; /* 112 12 */
/* XXX 4 bytes hole, try to pack */
/* --- cacheline 2 boundary (128 bytes) --- */
const struct can_tdc_const * tdc_const; /* 128 8 */
const u16 * termination_const; /* 136 8 */
unsigned int termination_const_cnt; /* 144 4 */
u16 termination; /* 148 2 */
/* XXX 2 bytes hole, try to pack */
const u32 * bitrate_const; /* 152 8 */
unsigned int bitrate_const_cnt; /* 160 4 */
/* XXX 4 bytes hole, try to pack */
const u32 * data_bitrate_const; /* 168 8 */
unsigned int data_bitrate_const_cnt; /* 176 4 */
u32 bitrate_max; /* 180 4 */
struct can_clock clock; /* 184 4 */
enum can_state state; /* 188 4 */
/* --- cacheline 3 boundary (192 bytes) --- */
u32 ctrlmode; /* 192 4 */
u32 ctrlmode_supported; /* 196 4 */
u32 ctrlmode_static; /* 200 4 */
int restart_ms; /* 204 4 */
struct delayed_work restart_work; /* 208 168 */
/* XXX last struct has 4 bytes of padding */
/* --- cacheline 5 boundary (320 bytes) was 56 bytes ago --- */
int (*do_set_bittiming)(struct net_device *); /* 376 8 */
/* --- cacheline 6 boundary (384 bytes) --- */
int (*do_set_data_bittiming)(struct net_device *); /* 384 8 */
int (*do_set_mode)(struct net_device *, enum can_mode); /* 392 8 */
int (*do_set_termination)(struct net_device *, u16); /* 400 8 */
int (*do_get_state)(const struct net_device *, enum can_state *); /* 408 8 */
int (*do_get_berr_counter)(const struct net_device *, struct can_berr_counter *); /* 416 8 */
unsigned int echo_skb_max; /* 424 4 */
/* XXX 4 bytes hole, try to pack */
struct sk_buff * * echo_skb; /* 432 8 */
/* size: 440, cachelines: 7, members: 31 */
/* sum members: 426, holes: 4, sum holes: 14 */
/* paddings: 1, sum paddings: 4 */
/* last cacheline: 56 bytes */
};
After:
$ pahole -C can_priv drivers/net/can/dev/dev.ostruct can_priv {
struct net_device * dev; /* 0 8 */
struct can_device_stats can_stats; /* 8 24 */
const struct can_bittiming_const * bittiming_const; /* 32 8 */
const struct can_bittiming_const * data_bittiming_const; /* 40 8 */
struct can_bittiming bittiming; /* 48 32 */
/* --- cacheline 1 boundary (64 bytes) was 16 bytes ago --- */
struct can_bittiming data_bittiming; /* 80 32 */
const struct can_tdc_const * tdc_const; /* 112 8 */
struct can_tdc tdc; /* 120 12 */
/* --- cacheline 2 boundary (128 bytes) was 4 bytes ago --- */
unsigned int bitrate_const_cnt; /* 132 4 */
const u32 * bitrate_const; /* 136 8 */
const u32 * data_bitrate_const; /* 144 8 */
unsigned int data_bitrate_const_cnt; /* 152 4 */
u32 bitrate_max; /* 156 4 */
struct can_clock clock; /* 160 4 */
unsigned int termination_const_cnt; /* 164 4 */
const u16 * termination_const; /* 168 8 */
u16 termination; /* 176 2 */
/* XXX 2 bytes hole, try to pack */
enum can_state state; /* 180 4 */
u32 ctrlmode; /* 184 4 */
u32 ctrlmode_supported; /* 188 4 */
/* --- cacheline 3 boundary (192 bytes) --- */
u32 ctrlmode_static; /* 192 4 */
int restart_ms; /* 196 4 */
struct delayed_work restart_work; /* 200 168 */
/* XXX last struct has 4 bytes of padding */
/* --- cacheline 5 boundary (320 bytes) was 48 bytes ago --- */
int (*do_set_bittiming)(struct net_device *); /* 368 8 */
int (*do_set_data_bittiming)(struct net_device *); /* 376 8 */
/* --- cacheline 6 boundary (384 bytes) --- */
int (*do_set_mode)(struct net_device *, enum can_mode); /* 384 8 */
int (*do_set_termination)(struct net_device *, u16); /* 392 8 */
int (*do_get_state)(const struct net_device *, enum can_state *); /* 400 8 */
int (*do_get_berr_counter)(const struct net_device *, struct can_berr_counter *); /* 408 8 */
unsigned int echo_skb_max; /* 416 4 */
/* XXX 4 bytes hole, try to pack */
struct sk_buff * * echo_skb; /* 424 8 */
/* size: 432, cachelines: 7, members: 31 */
/* sum members: 426, holes: 2, sum holes: 6 */
/* paddings: 1, sum paddings: 4 */
/* last cacheline: 48 bytes */
};
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
include/linux/can/dev.h | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 4795da0eb949..27b275e463da 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -39,22 +39,23 @@ struct can_priv {
struct net_device *dev;
struct can_device_stats can_stats;
- struct can_bittiming bittiming, data_bittiming;
const struct can_bittiming_const *bittiming_const,
*data_bittiming_const;
- struct can_tdc tdc;
+ struct can_bittiming bittiming, data_bittiming;
const struct can_tdc_const *tdc_const;
+ struct can_tdc tdc;
- const u16 *termination_const;
- unsigned int termination_const_cnt;
- u16 termination;
- const u32 *bitrate_const;
unsigned int bitrate_const_cnt;
+ const u32 *bitrate_const;
const u32 *data_bitrate_const;
unsigned int data_bitrate_const_cnt;
u32 bitrate_max;
struct can_clock clock;
+ unsigned int termination_const_cnt;
+ const u16 *termination_const;
+ u16 termination;
+
enum can_state state;
/* CAN controller features - see include/uapi/linux/can/netlink.h */
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v1 3/5] can: netlink: move '=' operators back to previous line (checkpatch fix)
2021-02-23 16:28 [PATCH v1 0/5] Introducing new CAN FD bittiming parameters: Transmission Delay Compensation (TDC) Vincent Mailhol
2021-02-23 16:28 ` [PATCH v1 1/5] can: add new CAN FD bittiming parameters: Transmitter " Vincent Mailhol
2021-02-23 16:28 ` [PATCH v1 2/5] can: dev: reorder struct can_priv members for better packing Vincent Mailhol
@ 2021-02-23 16:28 ` Vincent Mailhol
2021-02-23 19:47 ` Marc Kleine-Budde
2021-02-23 19:49 ` Marc Kleine-Budde
2021-02-23 16:28 ` [PATCH v1 4/5] can: add netlink interface for CAN-FD Transmitter Delay Compensation (TDC) Vincent Mailhol
2021-02-23 16:28 ` [PATCH v1 5/5] can: bittiming: add calculation for CAN FD " Vincent Mailhol
4 siblings, 2 replies; 11+ messages in thread
From: Vincent Mailhol @ 2021-02-23 16:28 UTC (permalink / raw)
To: Marc Kleine-Budde, linux-can, Oliver Hartkopp
Cc: Wolfgang Grandegger, Vincent Mailhol
Fix the warning triggered by having an '=' at the beginning of the
line and add one indentation to fix the alignment.
Extract of ./scripts/checkpatch.pl -f drivers/net/can/dev/netlink.c:
CHECK: Assignment operator '=' should be on the previous line
+ [IFLA_CAN_BITTIMING_CONST]
+ = { .len = sizeof(struct can_bittiming_const) },
CHECK: Assignment operator '=' should be on the previous line
+ [IFLA_CAN_DATA_BITTIMING]
+ = { .len = sizeof(struct can_bittiming) },
CHECK: Assignment operator '=' should be on the previous line
+ [IFLA_CAN_DATA_BITTIMING_CONST]
+ = { .len = sizeof(struct can_bittiming_const) },
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
drivers/net/can/dev/netlink.c | 26 ++++++++++++--------------
1 file changed, 12 insertions(+), 14 deletions(-)
diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index 867f6be31230..75851fab7ff5 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -8,20 +8,18 @@
#include <net/rtnetlink.h>
static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
- [IFLA_CAN_STATE] = { .type = NLA_U32 },
- [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
- [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
- [IFLA_CAN_RESTART] = { .type = NLA_U32 },
- [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
- [IFLA_CAN_BITTIMING_CONST]
- = { .len = sizeof(struct can_bittiming_const) },
- [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
- [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
- [IFLA_CAN_DATA_BITTIMING]
- = { .len = sizeof(struct can_bittiming) },
- [IFLA_CAN_DATA_BITTIMING_CONST]
- = { .len = sizeof(struct can_bittiming_const) },
- [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
+ [IFLA_CAN_STATE] = { .type = NLA_U32 },
+ [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
+ [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
+ [IFLA_CAN_RESTART] = { .type = NLA_U32 },
+ [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
+ [IFLA_CAN_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
+ [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
+ [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
+ [IFLA_CAN_DATA_BITTIMING] = { .len = sizeof(struct can_bittiming) },
+ [IFLA_CAN_DATA_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
+ [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
+ [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
};
static int can_validate(struct nlattr *tb[], struct nlattr *data[],
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH v1 3/5] can: netlink: move '=' operators back to previous line (checkpatch fix)
2021-02-23 16:28 ` [PATCH v1 3/5] can: netlink: move '=' operators back to previous line (checkpatch fix) Vincent Mailhol
@ 2021-02-23 19:47 ` Marc Kleine-Budde
2021-02-24 0:05 ` Vincent MAILHOL
2021-02-23 19:49 ` Marc Kleine-Budde
1 sibling, 1 reply; 11+ messages in thread
From: Marc Kleine-Budde @ 2021-02-23 19:47 UTC (permalink / raw)
To: Vincent Mailhol; +Cc: linux-can, Oliver Hartkopp, Wolfgang Grandegger
[-- Attachment #1: Type: text/plain, Size: 3278 bytes --]
On 24.02.2021 01:28:50, Vincent Mailhol wrote:
> Fix the warning triggered by having an '=' at the beginning of the
> line and add one indentation to fix the alignment.
>
> Extract of ./scripts/checkpatch.pl -f drivers/net/can/dev/netlink.c:
>
> CHECK: Assignment operator '=' should be on the previous line
> + [IFLA_CAN_BITTIMING_CONST]
> + = { .len = sizeof(struct can_bittiming_const) },
>
> CHECK: Assignment operator '=' should be on the previous line
> + [IFLA_CAN_DATA_BITTIMING]
> + = { .len = sizeof(struct can_bittiming) },
>
> CHECK: Assignment operator '=' should be on the previous line
> + [IFLA_CAN_DATA_BITTIMING_CONST]
> + = { .len = sizeof(struct can_bittiming_const) },
>
> Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
> ---
> drivers/net/can/dev/netlink.c | 26 ++++++++++++--------------
> 1 file changed, 12 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
> index 867f6be31230..75851fab7ff5 100644
> --- a/drivers/net/can/dev/netlink.c
> +++ b/drivers/net/can/dev/netlink.c
> @@ -8,20 +8,18 @@
> #include <net/rtnetlink.h>
>
> static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
> - [IFLA_CAN_STATE] = { .type = NLA_U32 },
> - [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
> - [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
> - [IFLA_CAN_RESTART] = { .type = NLA_U32 },
> - [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> - [IFLA_CAN_BITTIMING_CONST]
> - = { .len = sizeof(struct can_bittiming_const) },
> - [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
> - [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
> - [IFLA_CAN_DATA_BITTIMING]
> - = { .len = sizeof(struct can_bittiming) },
> - [IFLA_CAN_DATA_BITTIMING_CONST]
> - = { .len = sizeof(struct can_bittiming_const) },
> - [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
What about having only one space before and after the "="? Otherwise if
another entry is added wich is longer, the aligning would be broken again...
> + [IFLA_CAN_STATE] = { .type = NLA_U32 },
> + [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
> + [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
> + [IFLA_CAN_RESTART] = { .type = NLA_U32 },
> + [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> + [IFLA_CAN_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
> + [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
> + [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
> + [IFLA_CAN_DATA_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> + [IFLA_CAN_DATA_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
> + [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
> + [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
> };
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH v1 3/5] can: netlink: move '=' operators back to previous line (checkpatch fix)
2021-02-23 19:47 ` Marc Kleine-Budde
@ 2021-02-24 0:05 ` Vincent MAILHOL
0 siblings, 0 replies; 11+ messages in thread
From: Vincent MAILHOL @ 2021-02-24 0:05 UTC (permalink / raw)
To: Marc Kleine-Budde
Cc: linux-can, Oliver Hartkopp, Wolfgang Grandegger, Vincent Mailhol
Hi Marc,
On Wed. 24 Feb 2021 at 04:47, Marc Kleine-Budde <mkl@pengutronix.de> wrote:
>
> On 24.02.2021 01:28:50, Vincent Mailhol wrote:
> > Fix the warning triggered by having an '=' at the beginning of the
> > line and add one indentation to fix the alignment.
> >
> > Extract of ./scripts/checkpatch.pl -f drivers/net/can/dev/netlink.c:
> >
> > CHECK: Assignment operator '=' should be on the previous line
> > + [IFLA_CAN_BITTIMING_CONST]
> > + = { .len = sizeof(struct can_bittiming_const) },
> >
> > CHECK: Assignment operator '=' should be on the previous line
> > + [IFLA_CAN_DATA_BITTIMING]
> > + = { .len = sizeof(struct can_bittiming) },
> >
> > CHECK: Assignment operator '=' should be on the previous line
> > + [IFLA_CAN_DATA_BITTIMING_CONST]
> > + = { .len = sizeof(struct can_bittiming_const) },
> >
> > Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
> > ---
> > drivers/net/can/dev/netlink.c | 26 ++++++++++++--------------
> > 1 file changed, 12 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
> > index 867f6be31230..75851fab7ff5 100644
> > --- a/drivers/net/can/dev/netlink.c
> > +++ b/drivers/net/can/dev/netlink.c
> > @@ -8,20 +8,18 @@
> > #include <net/rtnetlink.h>
> >
> > static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
> > - [IFLA_CAN_STATE] = { .type = NLA_U32 },
> > - [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
> > - [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
> > - [IFLA_CAN_RESTART] = { .type = NLA_U32 },
> > - [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> > - [IFLA_CAN_BITTIMING_CONST]
> > - = { .len = sizeof(struct can_bittiming_const) },
> > - [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
> > - [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
> > - [IFLA_CAN_DATA_BITTIMING]
> > - = { .len = sizeof(struct can_bittiming) },
> > - [IFLA_CAN_DATA_BITTIMING_CONST]
> > - = { .len = sizeof(struct can_bittiming_const) },
> > - [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
>
> What about having only one space before and after the "="? Otherwise if
> another entry is added wich is longer, the aligning would be broken again...
Yes sir!
I do not have a strong preference between one style or the
other. Will resend the patch with a single space instead of
tabulations.
> > + [IFLA_CAN_STATE] = { .type = NLA_U32 },
> > + [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
> > + [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
> > + [IFLA_CAN_RESTART] = { .type = NLA_U32 },
> > + [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> > + [IFLA_CAN_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
> > + [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
> > + [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
> > + [IFLA_CAN_DATA_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> > + [IFLA_CAN_DATA_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
> > + [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
> > + [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
> > };
>
> Marc
>
> --
> Pengutronix e.K. | Marc Kleine-Budde |
> Embedded Linux | https://www.pengutronix.de |
> Vertretung West/Dortmund | Phone: +49-231-2826-924 |
> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v1 3/5] can: netlink: move '=' operators back to previous line (checkpatch fix)
2021-02-23 16:28 ` [PATCH v1 3/5] can: netlink: move '=' operators back to previous line (checkpatch fix) Vincent Mailhol
2021-02-23 19:47 ` Marc Kleine-Budde
@ 2021-02-23 19:49 ` Marc Kleine-Budde
2021-02-24 0:10 ` Vincent MAILHOL
1 sibling, 1 reply; 11+ messages in thread
From: Marc Kleine-Budde @ 2021-02-23 19:49 UTC (permalink / raw)
To: Vincent Mailhol; +Cc: linux-can, Oliver Hartkopp, Wolfgang Grandegger
[-- Attachment #1: Type: text/plain, Size: 2075 bytes --]
On 24.02.2021 01:28:50, Vincent Mailhol wrote:
[...]
> --- a/drivers/net/can/dev/netlink.c
> +++ b/drivers/net/can/dev/netlink.c
> @@ -8,20 +8,18 @@
> #include <net/rtnetlink.h>
>
> static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
> - [IFLA_CAN_STATE] = { .type = NLA_U32 },
> - [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
> - [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
> - [IFLA_CAN_RESTART] = { .type = NLA_U32 },
> - [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> - [IFLA_CAN_BITTIMING_CONST]
> - = { .len = sizeof(struct can_bittiming_const) },
> - [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
> - [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
> - [IFLA_CAN_DATA_BITTIMING]
> - = { .len = sizeof(struct can_bittiming) },
> - [IFLA_CAN_DATA_BITTIMING_CONST]
> - = { .len = sizeof(struct can_bittiming_const) },
> - [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
> + [IFLA_CAN_STATE] = { .type = NLA_U32 },
> + [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
> + [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
> + [IFLA_CAN_RESTART] = { .type = NLA_U32 },
> + [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> + [IFLA_CAN_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
> + [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
> + [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
> + [IFLA_CAN_DATA_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> + [IFLA_CAN_DATA_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
> + [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
> + [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
You doubled the last entry by mistake.
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH v1 3/5] can: netlink: move '=' operators back to previous line (checkpatch fix)
2021-02-23 19:49 ` Marc Kleine-Budde
@ 2021-02-24 0:10 ` Vincent MAILHOL
0 siblings, 0 replies; 11+ messages in thread
From: Vincent MAILHOL @ 2021-02-24 0:10 UTC (permalink / raw)
To: Marc Kleine-Budde; +Cc: linux-can, Oliver Hartkopp, Wolfgang Grandegger
Hi Marc,
On Wed. 24 Feb 2021 at 04:49, Marc Kleine-Budde <mkl@pengutronix.de> wrote:
>
> On 24.02.2021 01:28:50, Vincent Mailhol wrote:
> [...]
> > --- a/drivers/net/can/dev/netlink.c
> > +++ b/drivers/net/can/dev/netlink.c
> > @@ -8,20 +8,18 @@
> > #include <net/rtnetlink.h>
> >
> > static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
> > - [IFLA_CAN_STATE] = { .type = NLA_U32 },
> > - [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
> > - [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
> > - [IFLA_CAN_RESTART] = { .type = NLA_U32 },
> > - [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> > - [IFLA_CAN_BITTIMING_CONST]
> > - = { .len = sizeof(struct can_bittiming_const) },
> > - [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
> > - [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
> > - [IFLA_CAN_DATA_BITTIMING]
> > - = { .len = sizeof(struct can_bittiming) },
> > - [IFLA_CAN_DATA_BITTIMING_CONST]
> > - = { .len = sizeof(struct can_bittiming_const) },
> > - [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
> > + [IFLA_CAN_STATE] = { .type = NLA_U32 },
> > + [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
> > + [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
> > + [IFLA_CAN_RESTART] = { .type = NLA_U32 },
> > + [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> > + [IFLA_CAN_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
> > + [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
> > + [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
> > + [IFLA_CAN_DATA_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> > + [IFLA_CAN_DATA_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
> > + [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
> > + [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
>
> You doubled the last entry by mistake.
Arf...
As you noticed, the double entry is then removed in the next
patch. That is because I saw the issue but miserably modified the
wrong patch.
I will correct this in v2.
Yours sincerely,
Vincent
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH v1 4/5] can: add netlink interface for CAN-FD Transmitter Delay Compensation (TDC)
2021-02-23 16:28 [PATCH v1 0/5] Introducing new CAN FD bittiming parameters: Transmission Delay Compensation (TDC) Vincent Mailhol
` (2 preceding siblings ...)
2021-02-23 16:28 ` [PATCH v1 3/5] can: netlink: move '=' operators back to previous line (checkpatch fix) Vincent Mailhol
@ 2021-02-23 16:28 ` Vincent Mailhol
2021-02-23 19:52 ` Marc Kleine-Budde
2021-02-23 16:28 ` [PATCH v1 5/5] can: bittiming: add calculation for CAN FD " Vincent Mailhol
4 siblings, 1 reply; 11+ messages in thread
From: Vincent Mailhol @ 2021-02-23 16:28 UTC (permalink / raw)
To: Marc Kleine-Budde, linux-can, Oliver Hartkopp
Cc: Wolfgang Grandegger, Vincent Mailhol
Add the netlink interface for TDC parameters of struct can_tdc and
can_tdc_const.
Contrary to the can_bittiming(_const) structures for which there is
just a single IFLA_CAN(_DATA)_BITTMING(_CONST) entry per structure,
here, an IFLA_CAN_TDC* entry is added for each of the TDC parameters
of the newly introduced struct can_tdc and struct can_tdc_const.
For struct can_tdc, these are:
IFLA_CAN_TDCV
IFLA_CAN_TDCO
IFLA_CAN_TDCF
For struct can_tdc_const, these are:
IFLA_CAN_TDCV_MAX_CONST
IFLA_CAN_TDCO_MAX_CONST
IFLA_CAN_TDCF_MAX_CONST
This is done so that changes can be applied in the future to the
structures without breaking the netlink interface.
All the new parameters are defined as u32. This arbitrary choice is
done to mimic the other bittiming values with are also all of type
u32. An u16 would have been sufficient to hold the TDC values.
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
drivers/net/can/dev/netlink.c | 75 +++++++++++++++++++++++++++++++-
include/uapi/linux/can/netlink.h | 6 +++
2 files changed, 79 insertions(+), 2 deletions(-)
diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index 75851fab7ff5..f63e105d3df8 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -19,7 +19,12 @@ static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
[IFLA_CAN_DATA_BITTIMING] = { .len = sizeof(struct can_bittiming) },
[IFLA_CAN_DATA_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
[IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
- [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
+ [IFLA_CAN_TDCV] = { .type = NLA_U32 },
+ [IFLA_CAN_TDCV_MAX_CONST] = { .type = NLA_U32 },
+ [IFLA_CAN_TDCO] = { .type = NLA_U32 },
+ [IFLA_CAN_TDCO_MAX_CONST] = { .type = NLA_U32 },
+ [IFLA_CAN_TDCF] = { .type = NLA_U32 },
+ [IFLA_CAN_TDCF_MAX_CONST] = { .type = NLA_U32 },
};
static int can_validate(struct nlattr *tb[], struct nlattr *data[],
@@ -219,6 +224,51 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
priv->termination = termval;
}
+ if (data[IFLA_CAN_TDCV]) {
+ u32 tdcv = nla_get_u32(data[IFLA_CAN_TDCV]);
+
+ if (!priv->tdc_const || !priv->tdc_const->tdcv_max)
+ return -EOPNOTSUPP;
+
+ if (tdcv > priv->tdc_const->tdcv_max)
+ return -EINVAL;
+
+ if (dev->flags & IFF_UP)
+ return -EBUSY;
+
+ priv->tdc.tdcv = tdcv;
+ }
+
+ if (data[IFLA_CAN_TDCO]) {
+ u32 tdco = nla_get_u32(data[IFLA_CAN_TDCO]);
+
+ if (!priv->tdc_const || !priv->tdc_const->tdco_max)
+ return -EOPNOTSUPP;
+
+ if (tdco > priv->tdc_const->tdco_max)
+ return -EINVAL;
+
+ if (dev->flags & IFF_UP)
+ return -EBUSY;
+
+ priv->tdc.tdco = tdco;
+ }
+
+ if (data[IFLA_CAN_TDCF]) {
+ u32 tdcf = nla_get_u32(data[IFLA_CAN_TDCF]);
+
+ if (!priv->tdc_const || !priv->tdc_const->tdcf_max)
+ return -EOPNOTSUPP;
+
+ if (tdcf > priv->tdc_const->tdcf_max)
+ return -EINVAL;
+
+ if (dev->flags & IFF_UP)
+ return -EBUSY;
+
+ priv->tdc.tdcf = tdcf;
+ }
+
return 0;
}
@@ -253,6 +303,16 @@ static size_t can_get_size(const struct net_device *dev)
size += nla_total_size(sizeof(*priv->data_bitrate_const) *
priv->data_bitrate_const_cnt);
size += sizeof(priv->bitrate_max); /* IFLA_CAN_BITRATE_MAX */
+ if (priv->tdc.tdco) {
+ size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCV */
+ size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCO */
+ size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCF */
+ }
+ if (priv->tdc_const) {
+ size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCV_MAX_CONST */
+ size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCO_MAX_CONST */
+ size += nla_total_size(sizeof(u32)); /* IFLA_CAN_TDCF_MAX_CONST */
+ }
return size;
}
@@ -314,7 +374,18 @@ static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
(nla_put(skb, IFLA_CAN_BITRATE_MAX,
sizeof(priv->bitrate_max),
- &priv->bitrate_max))
+ &priv->bitrate_max)) ||
+
+ (priv->tdc_const &&
+ (nla_put_u32(skb, IFLA_CAN_TDCV, priv->tdc.tdcv) ||
+ nla_put_u32(skb, IFLA_CAN_TDCO, priv->tdc.tdco) ||
+ nla_put_u32(skb, IFLA_CAN_TDCF, priv->tdc.tdcf) ||
+ nla_put_u32(skb, IFLA_CAN_TDCV_MAX_CONST,
+ priv->tdc_const->tdcv_max) ||
+ nla_put_u32(skb, IFLA_CAN_TDCO_MAX_CONST,
+ priv->tdc_const->tdco_max) ||
+ nla_put_u32(skb, IFLA_CAN_TDCF_MAX_CONST,
+ priv->tdc_const->tdcf_max)))
)
return -EMSGSIZE;
diff --git a/include/uapi/linux/can/netlink.h b/include/uapi/linux/can/netlink.h
index f730d443b918..e69c4b330ae6 100644
--- a/include/uapi/linux/can/netlink.h
+++ b/include/uapi/linux/can/netlink.h
@@ -134,6 +134,12 @@ enum {
IFLA_CAN_BITRATE_CONST,
IFLA_CAN_DATA_BITRATE_CONST,
IFLA_CAN_BITRATE_MAX,
+ IFLA_CAN_TDCV,
+ IFLA_CAN_TDCO,
+ IFLA_CAN_TDCF,
+ IFLA_CAN_TDCV_MAX_CONST,
+ IFLA_CAN_TDCO_MAX_CONST,
+ IFLA_CAN_TDCF_MAX_CONST,
__IFLA_CAN_MAX
};
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH v1 4/5] can: add netlink interface for CAN-FD Transmitter Delay Compensation (TDC)
2021-02-23 16:28 ` [PATCH v1 4/5] can: add netlink interface for CAN-FD Transmitter Delay Compensation (TDC) Vincent Mailhol
@ 2021-02-23 19:52 ` Marc Kleine-Budde
0 siblings, 0 replies; 11+ messages in thread
From: Marc Kleine-Budde @ 2021-02-23 19:52 UTC (permalink / raw)
To: Vincent Mailhol; +Cc: linux-can, Oliver Hartkopp, Wolfgang Grandegger
[-- Attachment #1: Type: text/plain, Size: 804 bytes --]
On 24.02.2021 01:28:51, Vincent Mailhol wrote:
[...]
> --- a/drivers/net/can/dev/netlink.c
> +++ b/drivers/net/can/dev/netlink.c
> @@ -19,7 +19,12 @@ static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
> [IFLA_CAN_DATA_BITTIMING] = { .len = sizeof(struct can_bittiming) },
> [IFLA_CAN_DATA_BITTIMING_CONST] = { .len = sizeof(struct can_bittiming_const) },
> [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
> - [IFLA_CAN_TERMINATION] = { .type = NLA_U16 },
here you remove the double last entry.
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Embedded Linux | https://www.pengutronix.de |
Vertretung West/Dortmund | Phone: +49-231-2826-924 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH v1 5/5] can: bittiming: add calculation for CAN FD Transmitter Delay Compensation (TDC)
2021-02-23 16:28 [PATCH v1 0/5] Introducing new CAN FD bittiming parameters: Transmission Delay Compensation (TDC) Vincent Mailhol
` (3 preceding siblings ...)
2021-02-23 16:28 ` [PATCH v1 4/5] can: add netlink interface for CAN-FD Transmitter Delay Compensation (TDC) Vincent Mailhol
@ 2021-02-23 16:28 ` Vincent Mailhol
4 siblings, 0 replies; 11+ messages in thread
From: Vincent Mailhol @ 2021-02-23 16:28 UTC (permalink / raw)
To: Marc Kleine-Budde, linux-can, Oliver Hartkopp
Cc: Wolfgang Grandegger, Vincent Mailhol
The logic for the tdco calculation is to just reuse the normal sample
point: tdco = sp. Because the sample point is expressed in tenth of
percent and the tdco is expressed in time quanta, a conversion is
needed.
At the end,
ssp = tdcv + tdco
= tdcv + sp.
Another popular method is to set tdco to the middle of the bit:
tdc->tdco = can_bit_time(dbt) / 2
During benchmark tests, we could not find a clear advantages for one
of the two methods.
The tdco calculation is triggered each time the data_bittiming is
changed so that users relying on automated calculation can use the
netlink interface the exact same way without need of new parameters.
For example, a command such as:
ip link set canX type can bitrate 500000 dbitrate 4000000 fd on
would trigger the calculation.
The user using CONFIG_CAN_CALC_BITTIMING who does not want automated
calculation needs to manually set tdco to zero.
For example with:
ip link set canX type can tdco 0 bitrate 500000 dbitrate 4000000 fd on
(if the tdco parameter is provided in a previous command, it will be
overwritten).
If tdcv is set to zero (default), it is automatically calculated by
the transiver for each frame. As such, there is no code in the kernel
to calculate it.
tdcf has no automated calculation functions because we could not
figure out a formula for this parameter.
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
---
drivers/net/can/dev/bittiming.c | 23 +++++++++++++++++++++++
drivers/net/can/dev/netlink.c | 1 +
include/linux/can/bittiming.h | 6 ++++++
3 files changed, 30 insertions(+)
diff --git a/drivers/net/can/dev/bittiming.c b/drivers/net/can/dev/bittiming.c
index f7fe226bb395..5d6c2f217210 100644
--- a/drivers/net/can/dev/bittiming.c
+++ b/drivers/net/can/dev/bittiming.c
@@ -174,6 +174,29 @@ int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
return 0;
}
+
+void can_calc_tdco(struct net_device *dev)
+{
+ struct can_priv *priv = netdev_priv(dev);
+ const struct can_bittiming *dbt = &priv->data_bittiming;
+ struct can_tdc *tdc = &priv->tdc;
+ const struct can_tdc_const *tdc_const = priv->tdc_const;
+
+ if (!tdc_const)
+ return;
+
+ /* As specified in ISO 11898-1 section 11.3.3 "Transmitter
+ * delay compensation" (TDC) is only applicable if data BRP is
+ * one or two.
+ */
+ if (dbt->brp == 1 || dbt->brp == 2) {
+ /* Reuse "normal" sample point and convert it to time quanta */
+ tdc->tdco = min(can_bit_time(dbt) * dbt->sample_point / 1000,
+ tdc_const->tdco_max);
+ } else {
+ tdc->tdco = 0;
+ }
+}
#endif /* CONFIG_CAN_CALC_BITTIMING */
/* Checks the validity of the specified bit-timing parameters prop_seg,
diff --git a/drivers/net/can/dev/netlink.c b/drivers/net/can/dev/netlink.c
index f63e105d3df8..ed99d9392dfb 100644
--- a/drivers/net/can/dev/netlink.c
+++ b/drivers/net/can/dev/netlink.c
@@ -183,6 +183,7 @@ static int can_changelink(struct net_device *dev, struct nlattr *tb[],
priv->data_bitrate_const_cnt);
if (err)
return err;
+ can_calc_tdco(dev);
if (priv->bitrate_max && dbt.bitrate > priv->bitrate_max) {
netdev_err(dev, "canfd data bitrate surpasses transceiver capabilities of %d bps\n",
diff --git a/include/linux/can/bittiming.h b/include/linux/can/bittiming.h
index 91bf9f8926a7..8c042a025a7f 100644
--- a/include/linux/can/bittiming.h
+++ b/include/linux/can/bittiming.h
@@ -78,6 +78,8 @@ struct can_tdc_const {
#ifdef CONFIG_CAN_CALC_BITTIMING
int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
const struct can_bittiming_const *btc);
+
+void can_calc_tdco(struct net_device *dev);
#else /* !CONFIG_CAN_CALC_BITTIMING */
static inline int
can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
@@ -86,6 +88,10 @@ can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
netdev_err(dev, "bit-timing calculation not available\n");
return -EINVAL;
}
+
+static inline void can_calc_tdco(struct net_device *dev)
+{
+}
#endif /* CONFIG_CAN_CALC_BITTIMING */
int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
--
2.26.2
^ permalink raw reply related [flat|nested] 11+ messages in thread