Secondly, I found the following definition in the uboot source:
/* MT35XU512ABA1G12 has only one Die, so QSPI0 B won't work */
#ifdef CONFIG_FSL_FSPI
#define CONFIG_SF_DEFAULT_BUS 0
#define CONFIG_SF_DEFAULT_CS 0
#define CONFIG_SF_DEFAULT_SPEED 160000000 /***160Mhz***/
#define CONFIG_SF_DEFAULT_MODE SPI_MODE_0
#define FSL_FSPI_FLASH_SIZE SZ_64M
#define FSL_FSPI_FLASH_NUM 1
#define FSPI0_BASE_ADDR 0x5d120000
#define FSPI0_AMBA_BASE 0
#define CONFIG_SYS_FSL_FSPI_AHB
#endif
Among them MT36XU512ABA1G12 type has only one Die (QSPI0 B is not working), and we have two Dies with IS26KL512, it can not be used. How to configure QSPI0 B to work mode (ie 8-line working mode)?
The Die information for IS26KL512 is shown below:
