Commit f7ae3091 authored by Qianru Huang's avatar Qianru Huang Committed by Jiri Kosina
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Documentation: hid: intel-ish-hid: add section for firmware loading 



Add a section to describe the ISH firmware loading process for Lunar Lake
and later generations.

Signed-off-by: default avatarQianru Huang <qianru.huang@intel.com>
Signed-off-by: default avatarZhang Lixu <lixu.zhang@intel.com>
Acked-by: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.com>
parent 806a4c35

Documentation/hid/intel-ish-hid.rst

+65 −0
Original line number Diff line number Diff line
@@ -339,6 +339,71 @@ End to End HID transport Sequence Diagram 
          |                        |                       |                               |





ISH Firmware Loading from Host Flow

-----------------------------------



Starting from the Lunar Lake generation, the ISH firmware has been divided into two components for better space optimization and increased flexibility. These components include a bootloader that is integrated into the BIOS, and a main firmware that is stored within the operating system's file system.



The process works as follows:



- Initially, the ISHTP driver sends a command, HOST_START_REQ_CMD, to the ISH bootloader. In response, the bootloader sends back a HOST_START_RES_CMD. This response includes the ISHTP_SUPPORT_CAP_LOADER bit. Subsequently, the ISHTP driver checks if this bit is set. If it is, the firmware loading process from the host begins.



- During this process, the ISHTP driver first invokes the request_firmware() function, followed by sending a LOADER_CMD_XFER_QUERY command. Upon receiving a response from the bootloader, the ISHTP driver sends a LOADER_CMD_XFER_FRAGMENT command. After receiving another response, the ISHTP driver sends a LOADER_CMD_START command. The bootloader responds and then proceeds to the Main Firmware.



- After the process concludes, the ISHTP driver calls the release_firmware() function.



For more detailed information, please refer to the flow descriptions provided below:



::



  +---------------+                                                    +-----------------+

  | ISHTP Driver  |                                                    | ISH Bootloader  |

  +---------------+                                                    +-----------------+

          |                                                                     |

          |~~~Send HOST_START_REQ_CMD~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>|

          |                                                                     |

          |<--Send HOST_START_RES_CMD(Includes ISHTP_SUPPORT_CAP_LOADER bit)----|

          |                                                                     |

  ****************************************************************************************

  * if ISHTP_SUPPORT_CAP_LOADER bit is set                                               *

  ****************************************************************************************

          |                                                                     |

          |~~~start loading firmware from host process~~~+                      |

          |                                              |                      |

          |<---------------------------------------------+                      |

          |                                                                     |

  ---------------------------                                                   |

  | Call request_firmware() |                                                   |

  ---------------------------                                                   |

          |                                                                     |

          |~~~Send LOADER_CMD_XFER_QUERY~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>|

          |                                                                     |

          |<--Send response-----------------------------------------------------|

          |                                                                     |

          |~~~Send LOADER_CMD_XFER_FRAGMENT~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>|

          |                                                                     |

          |<--Send response-----------------------------------------------------|

          |                                                                     |

          |~~~Send LOADER_CMD_START~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~>|

          |                                                                     |

          |<--Send response-----------------------------------------------------|

          |                                                                     |

          |                                                                     |~~~Jump to Main Firmware~~~+

          |                                                                     |                           |

          |                                                                     |<--------------------------+

          |                                                                     |

  ---------------------------                                                   |

  | Call release_firmware() |                                                   |

  ---------------------------                                                   |

          |                                                                     |

  ****************************************************************************************

  * end if                                                                               *

  ****************************************************************************************

          |                                                                     |

  +---------------+                                                    +-----------------+

  | ISHTP Driver  |                                                    | ISH Bootloader  |

  +---------------+                                                    +-----------------+



ISH Debugging

-------------