Serial console over USB Gadget

[Steve Kreyer]

Hi all,

Iam new to the beagle board. Since Iam not able to get an idc-10 to
DB9 serial adapter I've tried to get a serial connection using USB
gadget.

This works fine for U-Boot but I get stucked on Linux.

If U-Boot boots, on the host a ttyACM0 device appears which can be
connected to using minicom. After loading the kernel image from MMC
into RAM and booting it, minicom looses the connection to ttyACM0.
Instead a new device appears on the host called ttyACM1. But if I try
connecting to it minicom locks in "modem initialization" state...
Thus, the kernel boot is a kind of black box for me since I cant see
whats going on there (Maybe there is a kernel oops?). But it seems
that it can initialize the serial USB gadget port because of the
ttyACM1 device on the host.

Here is my kernel config / what I've done so far / kernel host output:

Beagle Board's USB serial / gadget kernel config:
CONFIG_SERIAL_8250=y
CONFIG_SERIAL_8250_CONSOLE=y
CONFIG_SERIAL_8250_NR_UARTS=32
CONFIG_SERIAL_8250_RUNTIME_UARTS=4
CONFIG_SERIAL_8250_EXTENDED=y
CONFIG_SERIAL_8250_MANY_PORTS=y
CONFIG_SERIAL_8250_SHARE_IRQ=y
CONFIG_SERIAL_8250_DETECT_IRQ=y
CONFIG_SERIAL_8250_RSA=y

CONFIG_SERIAL_CORE=y
CONFIG_SERIAL_CORE_CONSOLE=y

CONFIG_USB_SERIAL=y
CONFIG_USB_SERIAL_CONSOLE=y
CONFIG_USB_SERIAL_GENERIC=y

CONFIG_USB_GADGET_MUSB_HDRC=y
CONFIG_USB_GADGET=y

CONFIG_USB_GADGET_VBUS_DRAW=2
CONFIG_USB_GADGET_SELECTED=y

CONFIG_USB_GADGET_DUALSPEED=y

What I've done so far on the U-Boot console:

OMAP3 beagleboard.org # mmc init
mmc1 is available
OMAP3 beagleboard.org # fatload mmc 0:2 0x80300000 uImage
reading uImage

1991316 bytes read
OMAP3 beagleboard.org # fatload mmc 0:2 0x81600000 rd-ext2.bin
reading rd-ext2.bin

3394477 bytes rea' - try 'help'
OMAP3 beagleboard.org #
OMAP3 beagleboard.org #
OMAP3 beagleboard.org #
OMAP3 beagleboard.org # setenv bootargs console=ttyGS0,115200n8
ramdisk_size=8192 root=/dev/ram0 rw initrd=0x81600000,8M nohz=off
rootfstype=ext2
OMAP3 beagleboard.org # bootm 0x80300000

And last bot not least the kernel output on the host:
redwing@euklid:~$ dmesg
usb 2-1: USB disconnect, address 6
usb 2-1: new high speed USB device using ehci_hcd and address 7
usb 2-1: config 1 interface 0 altsetting 0 endpoint 0x81 has an
invalid bInterval 255, changing to 11
usb 2-1: configuration #1 chosen from 1 choice
cdc_acm 2-1:1.0: This device cannot do calls on its own. It is not a
modem.
cdc_acm 2-1:1.0: ttyACM0: USB ACM device
<--- This is after booting U-Boot with working serial console on
ttyACM0.
usb 2-1: USB disconnect, address 7
tty_port_close_start: count = -1
usb 2-1: new high speed USB device using ehci_hcd and address 8
hub 2-0:1.0: unable to enumerate USB device on port 1
tty_port_close_start: count = -1
usb 2-1: new high speed USB device using ehci_hcd and address 9
usb 2-1: configuration #2 chosen from 1 choice
cdc_acm 2-1:2.0: This device cannot do calls on its own. It is not a
modem.
cdc_acm 2-1:2.0: ttyACM1: USB ACM device
<--- This is after kernel startup

If you need additional information, please let me know.

Any help on this issue would be very appreciated.

Kind Regards,
Steve

[evino...@gmail.com]

Hi,

Have you fixed this issue ? I am facing a similar issue, any info on the topic would be useful.