Hello,
As stated in i.MX 7Dual Reference Manual (RM), Rev. 1, 01/2018:
If the SPI flash device requires the quad enable command, it
can be sent via these configuration structure fields:
device_quad_mode_en, device_cmd, write_cmd_ipcr,
write_enable_ipcr, busy_bit_offset, and read_status_ipcr.
So, customers should properly write the parameters, described
in section 6.6.6.3 (QuadSPI configuration parameters) of the RM.
The ROM expects the QuadSPI configuration parameters (as explained in the QuadSPI
Configuration Parameters) to be present in the serial flash memory from the offset 0x400
of serial flash of length 512 bytes. The ROM reads these configuration parameters using
the default read command configured in the LUT of the QuadSPI interface with the
SCLOCK operating at 20 MHz.
In the second step, the ROM configures the selected QuadSPI interface with the
configuration parameters read from the serial flash and starts the boot procedure.
Regards,
Yuri.