From: Randy Dunlap <rdunlap@infradead.org>
To: Subhashini Rao Beerisetty <subhashbeerisetty@gmail.com>,
Greg KH <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org,
kernelnewbies <kernelnewbies@kernelnewbies.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: Embedded USB Debug(EUD) driver
Date: Sat, 7 Aug 2021 07:54:57 -0700 [thread overview]
Message-ID: <1cd59c72-2221-ec3a-da8d-ca377530db80@infradead.org> (raw)
In-Reply-To: <CAPY=qRTx+V_P1390b09wyBwMqDOJ2MBH8=5iBgfLCz6t_mBKwQ@mail.gmail.com>
On 8/7/21 7:23 AM, Subhashini Rao Beerisetty wrote:
> On Sat, Jul 31, 2021 at 11:12 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>>
>> On Fri, Jul 30, 2021 at 11:33:09PM +0530, Subhashini Rao Beerisetty wrote:
>>> Hi All,
>>>
>>> I'm currently looking for the Embedded USB Debug (EUD) interface driver.
>>
>> For what specific hardware? Do you have the needed "special" cable? We
>> have support in the kernel for some types of these cables, what kernel
>> versions have you tried that did not work for this?
> It's for MSM hardware and yes we have the "special" cable.
> I could not find the device driver for this in the mainline tree. It
> would be helpful if you could point me to the kernel tree which
> supports this feature. We will compile this suggested kernel and
> necessary drivers and then will give a try on our hardware
Hi,
See USB_SERIAL_DEBUG in drivers/usb/serial/.
That symbol builds usb_debug.c in that same directory.
It may help to read Documentation/x86/earlyprintk.rst.
My own cheat sheet (quick reference) says this: (it may or
may not help you) (it might need some updating for XHCI):
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Using USB debug port (on a USB EHCI controller)
On the system under test:
CONFIG_USB_EHCI_HCD=y
kernel command line:
earlyprintk=dbgpN,keep
With an XHCI controller, use:
earlyprintk=xdbcN,keep
Also add:
console=tty0
or console=ttyUSB0
for console output to go to the serial port.
Make sure that USB_SERIAL=y, USB_SERIAL_CONSOLE=y,
and USB_SERIAL_DEBUG=y.
------
On the logging system:
(requires CONFIG_USB_SERIAL_DEBUG=y)
Run minicom and tell it to connect to /dev/ttyUSB#.
Optionally have it log all messages to a file.
#####
--
~Randy
prev parent reply other threads:[~2021-08-07 14:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAPY=qRS0F0iv15w34w13xutoUThbDqFtYniM=eLLmqaMdXya3g@mail.gmail.com>
2021-07-31 5:42 ` Embedded USB Debug(EUD) driver Greg KH
2021-08-07 14:23 ` Subhashini Rao Beerisetty
2021-08-07 14:54 ` Randy Dunlap [this message]
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