Hi Thomas! > > On 8/14/24 20:47, Mary Strodl wrote: > > The following series adds support for the Congatec CGEB interface > > found on some Congatec x86 boards. The CGEB interface is a BIOS > > interface which provides access to onboard peripherals like I2C > > busses and watchdogs. It works by mapping BIOS code and searching > > for magic values which specify the entry points to the CGEB call. > > The CGEB call is an API provided by the BIOS which provides access > > to the functions in an ioctl like fashion. > > > > At the request of some folks the first time I sent this series out, > > CGEB has a userspace component which runs the x86 blob (rather than > > running it directly in the kernel), which sends requests back and > > forth using the cn_netlink API. > > > > You can find a reference implementation of the userspace helper here: > > https://github.com/Mstrodl/cgeb-helper > > > > I didn't get an answer when I asked where the userspace component > > should live, so I didn't put a ton of work into getting the helper > > up to snuff since similar userspace helpers (like v86d) are not > > in-tree. If folks would like the helper in-tree, that's fine too. > > Hello Mary !! > > It was by pure luck that I found your series. > > It seems we are working on the same thing, the Congatec Board Controller. > > I sent a first version of my series few weeks ago [1]. > My implementation is very different. > There is an MFD which maps the needed IO regions and declares cells > (gpio, watchdog, i2c). It also contains all the code to communicate with > the Board Controller (using ioread and iowrite). > The DMI table is used to detect if the board is supported, so the driver > can be probed (or not). > Other drivers (gpio, i2c and watchdog for now) use the API provided by > the MFD to communicate with the Board Controller. > With this approach, I don't need a userspace component. > > For this work I used the Congatec driver (that Thomas Gleixner pointed > you) as reference. But as mentioned by Thomas the driver is not well > written at all. > By the way their latest version is available in their yocto metalayer > (please find the link in my series). > I'm glad to see that Congatec has taken a different approach with their driver and is no longer relying on the BIOS blob method. Years ago, I shared my frustrations with them over this outdated solution through numerous phone calls, but the company I worked for was simply too small to have any real influence. > For now I did the job for the conga-SA7 board (which has a 5th > generation Board Controller). > So if you have hardware which has the same generation of the Board > Controller, you can easily test the series. You only need to add the DMI > entry of your board in the MFD driver. > > For other generations, I had a quick look. The sequences seem very > similar, with minor differences. It could be easily implemented in the > future, and only the MFD will be modified. > Fantastic news - looks like all the pain with this board controller under Linux is gone soon. -- greets -- Christian Gmeiner, MSc https://christian-gmeiner.info/privacypolicy
