diff options
| -rw-r--r-- | docs/case_closed_debugging.md | 31 | ||||
| -rw-r--r-- | extra/usb_serial/README.md | 4 |
2 files changed, 23 insertions, 12 deletions
diff --git a/docs/case_closed_debugging.md b/docs/case_closed_debugging.md index 2bd0d9727b..c3d0eb62ca 100644 --- a/docs/case_closed_debugging.md +++ b/docs/case_closed_debugging.md @@ -29,11 +29,13 @@ ChromiumOS SDK. ### Udev rules file There is a udev rules file, `extra/usb_serial/51-google-serial.rules` that should be installed in `/etc/udev/rules.d/` and udev should be told to reread -its rules. +its rules. This rules file can be installed using the +`extra/usb_serial/install` script. ### Kernel module A trivial Linux kernel module that identifies case closed debug capable USB -interfaces can be found in `extra/usb_serial`. +interfaces can be found in `extra/usb_serial`. This module is also built and +installed using the `extra/usb_serial/install` script. ### ChromiumOS chroot This is really only a requirement for using flashrom. If you only need access @@ -70,16 +72,21 @@ running kernel. It just adds an entry into the `usbserial` module's driver table that causes `usbserial` to recognize any case closed debugging serial console as a simple USB serial device. This addition has already made its way into the upstream kernel (v3.19), so eventually this module can be removed. -The `Makefile` in the `extra/usb_serial` directory will build the kernel module -against the current running kernel, and `insmod raiden.ko` will install it. -If installation fails due to missing dependencies you need to -`modprobe usbserial` first. - -An alternative to using this module is to install `usbserial` with -`modprobe usbserial vendor=<VID> product=<PID>`. The disadvantage of this method -is that it only works for an exact VID:PID match, and the module above does a -more detailed match of the USB descriptors to find interfaces that export the -Google simple serial vendor specific subclass. +The `extra/usb_serial/install` script will build and install the kernel module +as well as install the udev rules file. + +If for some reason you can't or don't want to use the kernel module the install +script provides a --fallback option that will install a udev rules file and +helper script instead that will add each new CCD capable device that is +attached to the host to the list of devices that usbserial will handle. The +disadvantage of this method is that it will generate `/dev/ttyUSB*` entries for +any USB interface on the device that has an IN/OUT pair of bulk endpoints. +This results in extra `/dev/ttyUSB*` entries that should not be used because +they are actually I2C or SPI bridges. + +The raiden module solves this by identifying a CCD serial port by the subclass +and protocol numbers of the USB device interface. This means that there does +not need to be a list of CCD capable device IDs anywhere. Use --- diff --git a/extra/usb_serial/README.md b/extra/usb_serial/README.md new file mode 100644 index 0000000000..f13e88eb24 --- /dev/null +++ b/extra/usb_serial/README.md @@ -0,0 +1,4 @@ +Case Closed Debugging Serial Consoles over USB +============================================== + +Please see the documentation in `../docs/case_closed_debugging.md`. |