[v6,0/2] usb: serial: add support for CH348

  Hello

The CH348 is an octo serial to USB adapter.
The following patch adds a driver for supporting it.
Since there is no public datasheet, unfortunatly it remains some magic values.

It was tested with a large range of baud from 1200 to 1500000 and used with
success in one of our kernel CI testlab.

Regards

Changes since v1:
- use a data structure for encoding/decoding messages.
- check if needed endpoints exists
- fix URB leak in ch348_allocate_status_read error case
- test for maximum baud rate as stated by datasheet

Changes since v2:
- specify ch348_rxbuf data length
- Use correct speed_t dwDTERate instead of __le32
- test for maximum baud rate supported according to datasheet
- Use a define for CH348_TX_HDRSIZE

Changes since v3
- Fixed all reported problem from https://lore.kernel.org/lkml/Y5NDwEakGJbmB6+b@Red/T/#mb6234d0427cfdabf412190565e215995a41482dd
  Mostly reworked the endpoint mux to be the same than mx_uport

Changes since v4:
- The V4 was sent against stable and next have ch348_set_termios ktermios
  parameter const that I forgot to change

Changes since v5:
- Fixed all reported problem from https://lore.kernel.org/lkml/20230106135338.643951-1-clabbe@baylibre.com/T/#m044aab24dfb652ea34aa06f8ef704da9d6a2e036
- Major change is dropping of all status handling which was unused.
  It will be probably necessary to bring it back when using GPIO.
  This will be done when I will finish my next devboard.

Corentin Labbe (2):
  usb: serial: add support for CH348
  usb: serial: add myself as maintainer of CH348

 MAINTAINERS                 |   5 +
 drivers/usb/serial/Kconfig  |   9 +
 drivers/usb/serial/Makefile |   1 +
 drivers/usb/serial/ch348.c  | 491 ++++++++++++++++++++++++++++++++++++
 4 files changed, 506 insertions(+)
 create mode 100644 drivers/usb/serial/ch348.c
  

Tested-by: David Heidelberg <david@ixit.cz>
Reviewed-by: David Heidelberg <david@ixit.cz>

Thank you

On 28/06/2023 15:38, Corentin Labbe wrote:
> Hello
>
> The CH348 is an octo serial to USB adapter.
> The following patch adds a driver for supporting it.
> Since there is no public datasheet, unfortunatly it remains some magic values.
>
> It was tested with a large range of baud from 1200 to 1500000 and used with
> success in one of our kernel CI testlab.
>
> Regards
>
> Changes since v1:
> - use a data structure for encoding/decoding messages.
> - check if needed endpoints exists
> - fix URB leak in ch348_allocate_status_read error case
> - test for maximum baud rate as stated by datasheet
>
> Changes since v2:
> - specify ch348_rxbuf data length
> - Use correct speed_t dwDTERate instead of __le32
> - test for maximum baud rate supported according to datasheet
> - Use a define for CH348_TX_HDRSIZE
>
> Changes since v3
> - Fixed all reported problem from https://lore.kernel.org/lkml/Y5NDwEakGJbmB6+b@Red/T/#mb6234d0427cfdabf412190565e215995a41482dd
>    Mostly reworked the endpoint mux to be the same than mx_uport
>
> Changes since v4:
> - The V4 was sent against stable and next have ch348_set_termios ktermios
>    parameter const that I forgot to change
>
> Changes since v5:
> - Fixed all reported problem from https://lore.kernel.org/lkml/20230106135338.643951-1-clabbe@baylibre.com/T/#m044aab24dfb652ea34aa06f8ef704da9d6a2e036
> - Major change is dropping of all status handling which was unused.
>    It will be probably necessary to bring it back when using GPIO.
>    This will be done when I will finish my next devboard.
>
> Corentin Labbe (2):
>    usb: serial: add support for CH348
>    usb: serial: add myself as maintainer of CH348
>
>   MAINTAINERS                 |   5 +
>   drivers/usb/serial/Kconfig  |   9 +
>   drivers/usb/serial/Makefile |   1 +
>   drivers/usb/serial/ch348.c  | 491 ++++++++++++++++++++++++++++++++++++
>   4 files changed, 506 insertions(+)
>   create mode 100644 drivers/usb/serial/ch348.c
>
  

Hello Corentin, light reminder about this patchset and Nicolas question :)

Thank you
David

On 30/08/2023 23:13, Nicolas Frattaroli wrote:
> On Mittwoch, 28. Juni 2023 15:38:32 CEST Corentin Labbe wrote:
>> Hello
>>
>> The CH348 is an octo serial to USB adapter.
>> The following patch adds a driver for supporting it.
>> Since there is no public datasheet, unfortunatly it remains some magic values.
>>
>> It was tested with a large range of baud from 1200 to 1500000 and used with
>> success in one of our kernel CI testlab.
>>
>> Regards
>>
>> [...]
> Hello,
>
> thank you for your work on this. I recently made myself a CH348
> board and used this patchset with a small test application[1]
> to see how it performs. Specifically, I ran this on an RK3566
> single board computer, connecting one serial adapter to the
> other, with the test as follows:
>
>   ./serialtest /dev/ttyUSB0 9600 # UART0 of 1st CH348 board
>   ./serialtest /dev/ttyUSB8 9600 # UART0 of 2nd CH348 board
>
> One problem I've noticed is that writes to the tty fd never
> seem to block. On two CH340 adapters I have, they do seem to
> block, whereas here, you can see from the statistics at the
> end that magnitudes more bytes were written than read, with
> seemingly most of them being discarded. From my reading of
> the termios parameters I set, this shouldn't be the case,
> right?
>
> You can see from the error percentage that it gets less
> bad as you increase the serial baudrate; I've tested up
> to 6 mbaud like this. I assume that's because less written
> bytes get discarded.
>
> Any ideas on whether I'm relying on weird driver behaviour
> with the blocking here or if this driver actually has a
> defect whereby it never signals to userspace that less
> bytes were written than have been submitted?
>
> Kind regards,
> Nicolas Frattaroli
>
> [1]: https://github.com/CounterPillow/serialtest
>
>
  

Le Wed, Aug 30, 2023 at 07:43:03PM +0200, Nicolas Frattaroli a écrit :
> On Mittwoch, 28. Juni 2023 15:38:32 CEST Corentin Labbe wrote:
> > Hello
> > 
> > The CH348 is an octo serial to USB adapter.
> > The following patch adds a driver for supporting it.
> > Since there is no public datasheet, unfortunatly it remains some magic values.
> > 
> > It was tested with a large range of baud from 1200 to 1500000 and used with
> > success in one of our kernel CI testlab.
> > 
> > Regards
> > 
> > [...]
> 
> Hello,
> 
> thank you for your work on this. I recently made myself a CH348
> board and used this patchset with a small test application[1]
> to see how it performs. Specifically, I ran this on an RK3566
> single board computer, connecting one serial adapter to the
> other, with the test as follows:
> 
>  ./serialtest /dev/ttyUSB0 9600 # UART0 of 1st CH348 board
>  ./serialtest /dev/ttyUSB8 9600 # UART0 of 2nd CH348 board
> 
> One problem I've noticed is that writes to the tty fd never
> seem to block. On two CH340 adapters I have, they do seem to
> block, whereas here, you can see from the statistics at the
> end that magnitudes more bytes were written than read, with
> seemingly most of them being discarded. From my reading of
> the termios parameters I set, this shouldn't be the case,
> right?
> 
> You can see from the error percentage that it gets less
> bad as you increase the serial baudrate; I've tested up
> to 6 mbaud like this. I assume that's because less written
> bytes get discarded.
> 
> Any ideas on whether I'm relying on weird driver behaviour
> with the blocking here or if this driver actually has a
> defect whereby it never signals to userspace that less
> bytes were written than have been submitted?
> 
> Kind regards,
> Nicolas Frattaroli
> 
> [1]: https://github.com/CounterPillow/serialtest
> 

Hello

Sorry for the very long delay of the answer.
I have reproduced the problem on my board.
My reproducer is https://github.com/montjoie/lava-tests/blob/master/test2a2.py

This problem seems to be here since the v1 of my patchset.
The vendor driver seems to work so it is not an hardware problem.

I have no clue at the moment, it is hard to diff with vendor driver since it create tty directly and do not use usbserial.

Regards