Re: [edk2-devel] [edk2-platforms] [PATCH V3 0/6] KabylakeOpenBoardPkg: HDMI DDC I2C Bus Debugging

Re: [edk2-devel] [edk2-platforms] [PATCH V3 0/6] KabylakeOpenBoardPkg: HDMI DDC I2C Bus Debugging

[Nate DeSimone]

The series has been pushed as 5f9e175~.. 4b2a5f4

-----Original Message-----
From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Nate DeSimone
Sent: Thursday, September 8, 2022 6:07 PM
To: devel@edk2.groups.io
Cc: Chiu, Chasel <chasel.chiu@intel.com>; Chaganty, Rangasai V <rangasai.v.chaganty@intel.com>; Oram, Isaac W <isaac.w.oram@intel.com>; Dong, Eric <eric.dong@intel.com>; Gao, Liming <gaoliming@byosoft.com.cn>; Benjamin Doron <benjamin.doron00@gmail.com>; Kubacki, Michael <michael.kubacki@microsoft.com>; Soller, Jeremy <jeremy@system76.com>
Subject: [edk2-devel] [edk2-platforms] [PATCH V3 0/6] KabylakeOpenBoardPkg: HDMI DDC I2C Bus Debugging

Changes in V3:
 - Added new HdmiDebugPchDetectionLib to eliminate
   duplicated code between I2cHdmiDebugSerialPortLib
   and HdmiDebugGpioInitLib.
 - Removed duplicated register definitions
 - Removed commented out code
 - Removed TODOs

Changes in V2:
 - Use SerialPortTerminalLib from MinPlatformPkg.
 - Override SerialPortLib on StatusCodeHandlerSmm not
   StatusCodeRouter.

Normally the HDMI DDC I2C bus is used to read the EDID data from the monitor. An unintended but useful property of this interface is that is does not require DMA to perform I/O. This means that this interface can be used to perform I/O before DRAM is initialized.

HDMI video output is a common feature of many laptops.
This makes the HDMI DDC bus the only I/O interface that is often exposed outside of the laptop chassis while simultaneously capable of being used in Pre-Memory.
Oddly... this makes it an ideal and novel way to perform closed chassis debug.

This patch series adds a implementation of using the HDMI DDC I2C Bus as a "poor man's" UART. This is accomplished using the GMBUS that is part of the Intel HD Graphics device. Accordingly, this implementation will only work on systems with the HDMI port routed to the Intel graphics device, and will not work on systems with HDMI routed to a discrete GPU.

In order to use this implementation, one will also need a BusPirate programmed with Nate's Custom Bus Pirate FW for I2C Serial Debug. This firmware is available from:

https://github.com/nate-desimone/Bus_Pirate

This firmware interfaces with the I2C Bus and forwards traffic from it to the FTDI USB Serial Adapter that is integrated with the BusPirate. In combination, this results in the HDMI port appearing to function as a regular UART to the user.

If you would like to see this in action, I made a short YouTube video:

https://www.youtube.com/watch?v=xe7cFhRsr80

Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Sai Chaganty <rangasai.v.chaganty@intel.com>
Cc: Isaac Oram <isaac.w.oram@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Benjamin Doron <benjamin.doron00@gmail.com>
Cc: Michael Kubacki <michael.kubacki@microsoft.com>
Cc: Jeremy Soller <jeremy@system76.com>
Signed-off-by: Nate DeSimone <nathaniel.l.desimone@intel.com>

Nate DeSimone (6):
  KabylakeOpenBoardPkg: Add HdmiDebugPchDetectionLib
  KabylakeOpenBoardPkg: Add I2cHdmiDebugSerialPortLib
  KabylakeOpenBoardPkg: Add HdmiDebugGpioInitLib
  KabylakeOpenBoardPkg: Add SecBoardInitLib
  MinPlatformPkg: Add PcdDefaultTerminalType support to
    SerialPortTerminalLib
  KabylakeOpenBoardPkg/GalagoPro3: Enable HDMI DDC Debug Port

 .../PeiAspireVn7Dash572GInitPreMemLib.c       |   3 +-
 .../AspireVn7Dash572G/OpenBoardPkg.dsc        |  12 +-
 .../AspireVn7Dash572G/OpenBoardPkgPcd.dsc     |   9 +
 .../BoardInitLib/PeiGalagoPro3InitPreMemLib.c |  13 +-
 .../GalagoPro3/OpenBoardPkg.dsc               |  85 +-
 .../GalagoPro3/OpenBoardPkgPcd.dsc            |  40 +
 .../Include/Library/HdmiDebugGpioInitLib.h    |  26 +
 .../Library/HdmiDebugPchDetectionLib.h        |  34 +
 .../PeiKabylakeRvp3InitPreMemLib.c            |  13 +-
 .../KabylakeRvp3/OpenBoardPkg.dsc             |  12 +-
 .../KabylakeRvp3/OpenBoardPkgPcd.dsc          |   9 +
 .../HdmiDebugGpioInitLib.c                    | 163 ++++
 .../HdmiDebugGpioInitLib.inf                  |  43 +
 .../HdmiDebugPchDetectionLib.c                |  67 ++
 .../HdmiDebugPchDetectionLib.inf              |  38 +
 .../DxeI2cHdmiDebugSerialPortLib.inf          |  53 ++
 .../DxeSmmI2cHdmiDebugSerialPortLib.c         | 161 ++++
 .../Library/I2cHdmiDebugSerialPortLib/Gmbus.c | 755 ++++++++++++++++++  .../Library/I2cHdmiDebugSerialPortLib/Gmbus.h | 319 ++++++++
 .../I2cDebugPortProtocol.c                    | 189 +++++
 .../I2cDebugPortProtocol.h                    |  77 ++
 .../I2cDebugPortTplDxe.c                      |  44 +
 .../I2cDebugPortTplNull.c                     |  36 +
 .../I2cHdmiDebugSerialPortLib.c               | 198 +++++
 .../I2cHdmiDebugSerialPortLib/IgfxI2c.c       |  79 ++
 .../I2cHdmiDebugSerialPortLib/IgfxI2c.h       |  99 +++
 .../PeiI2cHdmiDebugSerialPortLib.c            | 224 ++++++
 .../PeiI2cHdmiDebugSerialPortLib.inf          |  54 ++
 .../SecI2cHdmiDebugSerialPortLib.c            | 134 ++++
 .../SecI2cHdmiDebugSerialPortLib.inf          |  53 ++
 .../SmmI2cHdmiDebugSerialPortLib.inf          |  53 ++
 .../SecBoardInitLib/Ia32/SecBoardInit.nasm    |  18 +
 .../Library/SecBoardInitLib/SecBoardInitLib.c |  35 +
 .../SecBoardInitLib/SecBoardInitLib.inf       |  39 +
 .../KabylakeOpenBoardPkg/OpenBoardPkg.dec     |  33 +-
 .../SerialPortTerminalLib.c                   |  66 +-
 .../SerialPortTerminalLib.h                   |  11 +-
 .../SerialPortTerminalLib.inf                 |  17 +-
 38 files changed, 3259 insertions(+), 55 deletions(-)  create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Include/Library/HdmiDebugGpioInitLib.h
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Include/Library/HdmiDebugPchDetectionLib.h
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/HdmiDebugGpioInitLib/HdmiDebugGpioInitLib.c
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/HdmiDebugGpioInitLib/HdmiDebugGpioInitLib.inf
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/HdmiDebugPchDetectionLib/HdmiDebugPchDetectionLib.c
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/HdmiDebugPchDetectionLib/HdmiDebugPchDetectionLib.inf
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/DxeI2cHdmiDebugSerialPortLib.inf
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/DxeSmmI2cHdmiDebugSerialPortLib.c
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/Gmbus.c
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/Gmbus.h
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/I2cDebugPortProtocol.c
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/I2cDebugPortProtocol.h
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/I2cDebugPortTplDxe.c
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/I2cDebugPortTplNull.c
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/I2cHdmiDebugSerialPortLib.c
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/IgfxI2c.c
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/IgfxI2c.h
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/PeiI2cHdmiDebugSerialPortLib.c
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/PeiI2cHdmiDebugSerialPortLib.inf
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/SecI2cHdmiDebugSerialPortLib.c
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/SecI2cHdmiDebugSerialPortLib.inf
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/I2cHdmiDebugSerialPortLib/SmmI2cHdmiDebugSerialPortLib.inf
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/SecBoardInitLib/Ia32/SecBoardInit.nasm
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/SecBoardInitLib/SecBoardInitLib.c
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/Library/SecBoardInitLib/SecBoardInitLib.inf

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2.27.0.windows.1