According to the i.MX 8M Plus reference manual (Rev 1), 11.2.1.2, the USB controller "Supports four programmable, bidirectional USB endpoints".
However, if I read address 0x3810c14c (GHWPARAMS3), I read the value 0x08210085. This would indicate that DWC_USB3_NUM_EPS is 16 and DWC_USB3_NUM_IN_EPS is 8.
This is also consistent with my testing. I have tried to enumerate a Function FS device with varying number of endpoints. I am able to enumerate with up to 7 IN and 7 OUT endpoints. Anything more than that causes an error. Given that the bidirectional control endpoint 0 will always occupy one IN/OUT endpoint pair, this seems to be in line with the values I read from the register.
Is the data sheet wrong? Do I have to worry that newer revisions of the chip will be limited to 4 bidirectional endpoints?
