DRV8873-Q1: Where is the output of the chip output to the fault information protection such as short circuit to ground, and how can the customer identify it?

Hi Xiaofu, 

Please refer to section 7.3.2 for all the motor drive protection circuits. The reporting method and the behavior after fault are all specified there. There is a dedicated fault pin on this device to report certain faults. Here is the datasheet:

DRV8873 H-Bridge Motor Driver datasheet (ti.com)

Best,

Keerthi