I have an i.MX 8M Plus-EVK board with lpddr 6GB size.
I am trying to change ddr size 6GB to 4GB.
But I don't understand how to change uboot source.
1. include/configs/imx8mp_evk.h
/* Totally 6GB DDR */
#define CONFIG_SYS_SDRAM_BASE 0x40000000
#define PHYS_SDRAM 0x40000000
#define PHYS_SDRAM_SIZE 0xC0000000 /* 3 GB */
#define PHYS_SDRAM_2 0x1,0000,0000
#ifdef CONFIG_TARGET_IMX8MP_DDR4_EVK
#define PHYS_SDRAM_2_SIZE 0x40000000 /* 1 GB */
#else
#define PHYS_SDRAM_2_SIZE 0xC0000000 /* 3 GB */
#endif
I checked define CONFIG_TARGET_IMX8MP_DDR4_EVK=y. This setup should work for a total of 4GB. why ddr size is 6GB?
2. dtb in uboot
memory@40000000 {
device_type = "memory";
reg = <0x0 0x40000000 0 0xc0000000>, /* 3GB */
<0x1 0x00000000 0 0xc0000000>; /* 3GB */
};
I checked memory map in 2.2 Cortex-A53 Memory map of i.MX 8M Plus Application Processor Reference Manual.
----------------------------------------------------------------------------------------------------------------------------------
1_0000_0000 | 2_3FFF_FFFF | DDR Address | 5120MB DDR | Memory (All modules except M7)
4000_0000 | FFFF_FFFF | DDR Address | 3072MB DDR | Memory (All modules)
----------------------------------------------------------------------------------------------------------------------------------
I do not understand line "<0x1 0x00000000 0 0xc0000000>; /* 3GB */".
Does it have something to do with PHYS_SDRAM_2_SIZE and <0x1 0x00000000 0 0xc0000000> ?
please let me know how to work it.
Finally I am trying to set up it follows.
reg = <0x0 0x40000000 0 0xc0000000>, /* 3GB */
<0x1 0x00000000 0 0x10000000>; /* 1GB */
Is it correct?
