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Diffstat (limited to 'docs/ap-ec-comm.md')
| -rw-r--r-- | docs/ap-ec-comm.md | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/docs/ap-ec-comm.md b/docs/ap-ec-comm.md index 4270fca5f8..6f1292bcaf 100644 --- a/docs/ap-ec-comm.md +++ b/docs/ap-ec-comm.md @@ -120,6 +120,27 @@ cat /sys/kernel/debug/tracing/trace 369.421383: cros_ec_request_done: version: 0, command: EC_CMD_USB_PD_DISCOVERY, ec result: EC_RES_SUCCESS, retval: 5 ``` +## API synchronization + +EC, coreboot, user space (`platform2)` and kernel needs to access the same +information contained in `ec_commands.h`. + +* Coreboot regularly update [ec_commands.h]. +* User space/depthcharge use `ec_commands.h` installed by + `chromeos-base/chromeos-ec-headers` package. +* Kernel `ec_commands.h` - named + `./include/linux/platform_data/cros_ec_commands.h` - is not a direct +copy. New commands and options are added on a need-to-know basis +alongside the kernel code that uses these commands. + +A copy of `ec_commands.h`, matching kernel standard is auto-generated at +`/build/kernel/include/linux/mfd/cros_ec_commands.h` when +`make build_cros_ec_commands` or `make buildall` is run. (It is far from +perfect, since the kernel include file has not been updated with `clang-format` as +`ec_commands.h` has been). Copy the necessary changes from that file to +`include/linux/platform_data/cros_ec_commands.h` and push the changes upstream +first following the [upstream instructions]. + ## Transport-specific details Although the command and response formats are the same across all transports, @@ -179,3 +200,5 @@ after receiving a host packet and before it has a response ready. [Industrial I/O]: https://www.kernel.org/doc/html/v4.14/driver-api/iio/index.html [host command task]: https://chromium.googlesource.com/chromiumos/platform/ec/+/HEAD/common/host_command.c [Transport-specific details]: #Transport_specific-details +[ec_commands.h]: https://source.chromium.org/chromiumos/chromiumos/codesearch/+/main:src/third_party/coreboot/src/ec/google/chromeec/ec_commands.h +[upstream instructions]: https://chromium.googlesource.com/chromiumos/docs/+/HEAD/kernel_development.md#Upstream-development. |