mainboard: add Dell Latitude E7240

Based on autoport output.

It boots to Arch Linux (Linux 6.6.3) from USB and mSATA with SeaBIOS.

Change-Id: I6933bdbcc8d0bbb85d62657624740266284ac71c
Signed-off-by: Iru Cai <mytbk920423@gmail.com>
Signed-off-by: Nicholas Chin <nic.c3.14@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/79746
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>

Documentation/mainboard/dell/e7240.md

@@ -0,0 +1,83 @@
+# Dell Latitude E7240
+
+This page is about the notebook [Dell Latitude E7240].
+
+## Release status
+
+Dell Latitude E7240 was released in 2013 and is now end of life.
+It can be bought from a secondhand market like Taobao or eBay.
+
+## Required proprietary blobs
+
+The following blobs are required to operate the hardware:
+1. mrc.bin
+2. Intel ME firmware
+
+Memory reference code in mrc.bin is used to initialize the Haswell platform.
+You need this blob to build a working coreboot image. Please read
+[mrc.bin](../../northbridge/intel/haswell/mrc.bin) for instructions on
+retrieving and using it.
+
+Intel ME firmware is in the flash chip. It is not needed when building coreboot.
+It can be extracted from the OEM firmware. You can also flash only the BIOS
+region to leave Intel ME firmware untouched.
+
+## Programming
+
+The laptop can be flashed internally under OEM firmware using [dell-flash-unlock].
+
+To flash with an external programmer, you need to remove the battery and the base cover.
+
+![Dell Latitude E7240 mainboard](e7240.webp)
+
+For more details have a look at the general [flashing tutorial].
+
+It is also possible to flash internally under coreboot.
+
+## Debugging
+
+The board can be debugged with EHCI debug. The EHCI debug port is next to the miniDP port.
+
+There's a serial port on dock, but it's not yet supported in coreboot.
+
+Schematic of this laptop can be found online. The board name is Compal LA-9431P.
+
+## Test status
+
+### Not working
+
+- EC ACPI
+- SD/MMC card reader (kernel reports "Timeout waiting for hardware cmd interrupt.")
+- No internal display before booting to OS when connected with a dock
+
+### Working
+
+- Integrated graphics init with libgfxinit
+- mSATA
+- WLAN
+- USB
+- Keyboard
+- Touchpad and the buttons on it
+- Dock: all USB ports, DisplayPort, eSATA
+- Internal flashing
+
+
+## Technology
+
+```{eval-rst}
++------------------+-----------------------------+
+| CPU              | Intel Haswell-ULT           |
++------------------+-----------------------------+
+| PCH              | Intel Lynx Point Low Power  |
++------------------+-----------------------------+
+| EC               | SMSC MEC5075                |
++------------------+-----------------------------+
+| Super I/O        | SMSC ECE5048                |
++------------------+-----------------------------+
+| Coprocessor      | Intel Management Engine     |
++------------------+-----------------------------+
+```
+
+[Dell Latitude E7240]: https://www.dell.com/support/home/en-us/product-support/product/latitude-e7240-ultrabook/docs
+[dell-flash-unlock]: https://github.com/nic3-14159/dell-flash-unlock
+[flashing tutorial]: ../../flash_tutorial/ext_power.md

Documentation/mainboard/index.md

@@ -76,6 +76,7 @@ N130WU / N131WU <clevo/n130wu/index.md>
 ```{toctree}
 :maxdepth: 1
 
+Latitude E7240 <dell/e7240.md>
 OptiPlex 9010 SFF <dell/optiplex_9010.md>
 ```