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[PATCH v2 0/6] can: slcan: extend supported features (step 2)

Dario Binacchi posted 6 patches 3 years, 4 months ago
There is a newer version of this series
MAINTAINERS                        |   6 +
drivers/net/can/slcan/slcan-core.c | 451 +++++++++--------------------
2 files changed, 139 insertions(+), 318 deletions(-)
[PATCH v2 0/6] can: slcan: extend supported features (step 2)
Posted by Dario Binacchi 3 years, 4 months ago 
With this series I try to finish the task, started with the series [1],
of completely removing the dependency of the slcan driver from the
userspace slcand/slcan_attach applications.

The series, however, still lacks a patch for sending the bitrate setting
command to the adapter:

slcan_attach -b <btr> <dev>

Without at least this patch the task cannot be considered truly completed.

The idea I got is that this can only happen through the ethtool API.
Among the various operations made available by this interface I would
have used the set_regs (but only the get_regs has been developed), or,
the set_eeprom, even if the setting would not be stored in an eeprom.
IMHO it would take a set_regs operation with a `struct ethtool_wregs'
parameter similar to `struct ethtool_eeprom' without the magic field:

struct ethtool_wregs {
	__u32	cmd;
	__u32	offset;
	__u32	len;
	__u8	data[0];
};

But I am not the expert and if there was an alternative solution already
usable, it would be welcome.

The series also contains patches that remove the legacy stuff (slcan_devs,
SLCAN_MAGIC, ...) and do some module cleanup.

The series has been created on top of the patches:

can: slcan: convert comments to network style comments
can: slcan: slcan_init() convert printk(LEVEL ...) to pr_level()
can: slcan: fix whitespace issues
can: slcan: convert comparison to NULL into !val
can: slcan: clean up if/else
can: slcan: use scnprintf() as a hardening measure
can: slcan: do not report txerr and rxerr during bus-off
can: slcan: do not sleep with a spin lock held

applied to linux-next.

[1] https://lore.kernel.org/all/20220628163137.413025-1-dario.binacchi@amarulasolutions.com/

Changes in v2:
- Re-add headers that export at least one symbol used by the module.
- Update the commit description.
- Drop the old "slcan" name to use the standard canX interface naming.
- Remove comment on listen-only command.
- Update the commit subject and description.
- Add the patch "MAINTAINERS: Add myself as maintainer of the SLCAN driver"
  to the series.

Dario Binacchi (6):
  can: slcan: remove useless header inclusions
  can: slcan: remove legacy infrastructure
  can: slcan: change every `slc' occurrence in `slcan'
  can: slcan: use the generic can_change_mtu()
  can: slcan: add support for listen-only mode
  MAINTAINERS: Add maintainer for the slcan driver

 MAINTAINERS                        |   6 +
 drivers/net/can/slcan/slcan-core.c | 451 +++++++++--------------------
 2 files changed, 139 insertions(+), 318 deletions(-)

-- 
2.32.0
Re: [PATCH v2 0/6] can: slcan: extend supported features (step 2)
Posted by Marc Kleine-Budde 3 years, 4 months ago 
On 25.07.2022 08:54:13, Dario Binacchi wrote:
> With this series I try to finish the task, started with the series [1],
> of completely removing the dependency of the slcan driver from the
> userspace slcand/slcan_attach applications.
> 
> The series, however, still lacks a patch for sending the bitrate setting
> command to the adapter:
> 
> slcan_attach -b <btr> <dev>
> 
> Without at least this patch the task cannot be considered truly completed.
> 
> The idea I got is that this can only happen through the ethtool API.
> Among the various operations made available by this interface I would
> have used the set_regs (but only the get_regs has been developed), or,
> the set_eeprom, even if the setting would not be stored in an eeprom.
> IMHO it would take a set_regs operation with a `struct ethtool_wregs'
> parameter similar to `struct ethtool_eeprom' without the magic field:

This doesn't feel right.

> struct ethtool_wregs {
> 	__u32	cmd;
> 	__u32	offset;
> 	__u32	len;
> 	__u8	data[0];
> };
> 
> But I am not the expert and if there was an alternative solution already
> usable, it would be welcome.

Have a look at the get/set_tunable() callback:

| https://elixir.bootlin.com/linux/latest/source/include/linux/ethtool.h#L575

You probably have to add a new tunable. Here you'll find the people and
commits that changed the tunable:

| https://github.com/torvalds/linux/blame/master/include/uapi/linux/ethtool.h#L229

It's usually worth including them in an RFC patch series where you add a
new tunable and make use of it in the slcan driver.

regards,
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 |
Re: [PATCH v2 0/6] can: slcan: extend supported features (step 2)
Posted by Dario Binacchi 3 years, 4 months ago 
Hello Marc,

On Mon, Jul 25, 2022 at 3:25 PM Marc Kleine-Budde <mkl@pengutronix.de> wrote:
>
> On 25.07.2022 08:54:13, Dario Binacchi wrote:
> > With this series I try to finish the task, started with the series [1],
> > of completely removing the dependency of the slcan driver from the
> > userspace slcand/slcan_attach applications.
> >
> > The series, however, still lacks a patch for sending the bitrate setting
> > command to the adapter:
> >
> > slcan_attach -b <btr> <dev>
> >
> > Without at least this patch the task cannot be considered truly completed.
> >
> > The idea I got is that this can only happen through the ethtool API.
> > Among the various operations made available by this interface I would
> > have used the set_regs (but only the get_regs has been developed), or,
> > the set_eeprom, even if the setting would not be stored in an eeprom.
> > IMHO it would take a set_regs operation with a `struct ethtool_wregs'
> > parameter similar to `struct ethtool_eeprom' without the magic field:
>
> This doesn't feel right.
>
> > struct ethtool_wregs {
> >       __u32   cmd;
> >       __u32   offset;
> >       __u32   len;
> >       __u8    data[0];
> > };
> >
> > But I am not the expert and if there was an alternative solution already
> > usable, it would be welcome.
>
> Have a look at the get/set_tunable() callback:
>
> | https://elixir.bootlin.com/linux/latest/source/include/linux/ethtool.h#L575
>
> You probably have to add a new tunable. Here you'll find the people and
> commits that changed the tunable:
>
> | https://github.com/torvalds/linux/blame/master/include/uapi/linux/ethtool.h#L229
>
> It's usually worth including them in an RFC patch series where you add a
> new tunable and make use of it in the slcan driver.

Thank you very much for the suggestions.
Regards,

Dario
>
> regards,
> 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 |



-- 

Dario Binacchi

Embedded Linux Developer

dario.binacchi@amarulasolutions.com

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