Why does Intel Agilex® 7 SoC FPGA fail to access DDR space when HPS EMIF is enabled with Half Rate Converter (HRC) On and Quarter Rate?

Due to a problem with u-boot-spl(u-boot-socfpga-v2022.01) for Intel Agilex® 7 SoC FPGA, you may not be able to access all HPS DDR space when HPS EMIF is enabled with Half Rate Converter (HRC) On and Quarter Rate.  For example, if HPS EMIF is a 2GB configuration, HPS can only access the first half of 2GB, and the second half of 2GB is just an alias for the first half.

To work around this problem, you need to change the source code in u-boot-socfpga/drivers/ddr/altera/sdram_agilex.c(81) from   

   update_value |= (hmc_readl(plat, CTRLCFG3) & 0x4);

To

   update_value |= 0x4;

This problem is scheduled to be fixed in a future release of the u-boot-spl.