Boot Mode Writer Service

Introduction

The boot mode writer service can be used to program boot mode efuses present on devices to support reduced boot pin mode feature. A host provided in the boot mode writer configuration substructure in the general boardconfig structure can use this service. The service accepts the boot mode efuse index and the 32-bit raw fuse value as inputs.

Note

The value of a boot mode efuse cannot be modified after programming.

How to derive to-be programmed value?

One needs the following data items: #. Raw boot mode value for the boot mode of interest. This value is fixed for every boot mode on a device. #. The 25-bit bitmask for the efuse which has to be programmed.

The following figure demonstrates the procedure to derive the value to be sent over tisci message.

../_images/boot_mode_value_calc.png

How to get the values?

You need the following data items to derive the boot mode value (to send over tisci) for a boot mode of interest:

  1. Raw boot mode value. (Refer the Boot Mode Pins Section of the TRM)
  2. The efuse bitmask. (Refer the boot mode efuse soc document)