From: Emanuele Ghidoli <[email protected]> Use alias-based RAM probing to detect different memory configurations on Toradex SMARC iMX95. The address wrap-around is not linear: address bits above the module capacity alias back with some low address bits XORed (bit 32 -> XOR 0xc000), as measured on 4GB and 8GB modules.
During probing, skip the first 256MB, since that region is reserved. Signed-off-by: Emanuele Ghidoli <[email protected]> --- board/toradex/smarc-imx95/smarc-imx95.c | 23 ++++++++++++++++++++++- include/configs/toradex-smarc-imx95.h | 15 +++++++++------ 2 files changed, 31 insertions(+), 7 deletions(-) diff --git a/board/toradex/smarc-imx95/smarc-imx95.c b/board/toradex/smarc-imx95/smarc-imx95.c index 6040c49975a3..d09ce8a52abe 100644 --- a/board/toradex/smarc-imx95/smarc-imx95.c +++ b/board/toradex/smarc-imx95/smarc-imx95.c @@ -3,14 +3,35 @@ #include <asm/arch/clock.h> #include <asm/arch/sys_proto.h> +#include <errno.h> #include <fdt_support.h> #include <init.h> #include "../common/tdx-cfg-block.h" +/* + * The address wrap-around is not linear: address bits above the module + * capacity alias back to the base with some low address bits XORed, as + * measured on 4GB and 8GB modules (bit 32 -> XOR 0xc000, bit 33 -> XOR + * 0x2000). + */ +static const struct ram_alias_check ram_alias_checks[] = { + { (void *)((uintptr_t)PHYS_SDRAM + SZ_4G), (void *)((uintptr_t)PHYS_SDRAM + 0xc000), SZ_8G }, + { (void *)((uintptr_t)PHYS_SDRAM + SZ_2G), (void *)(PHYS_SDRAM), SZ_4G }, + { NULL } +}; + int board_phys_sdram_size(phys_size_t *size) { - *size = PHYS_SDRAM_SIZE + PHYS_SDRAM_2_SIZE; + phys_size_t sz; + + sz = probe_ram_size_by_alias(ram_alias_checks); + if (!sz) { + puts("## WARNING: Less than 4GB RAM detected\n"); + return -EINVAL; + } + + *size = sz - PHYS_SDRAM_FW_RSVD; return 0; } diff --git a/include/configs/toradex-smarc-imx95.h b/include/configs/toradex-smarc-imx95.h index 8a880b965038..97e3322ac282 100644 --- a/include/configs/toradex-smarc-imx95.h +++ b/include/configs/toradex-smarc-imx95.h @@ -7,16 +7,19 @@ #include <linux/sizes.h> #include <asm/arch/imx-regs.h> -/* module has 8GB, 2GB from 0x80000000..0xffffffff, 6GB above */ +/* module has 8GB, 2GB from 0x80000000..0xffffffff, 6GB above. + * Actual size is determined at runtime. + */ #define SZ_6G _AC(0x180000000, ULL) -/* first 256MB reserved for firmware */ -#define CFG_SYS_INIT_RAM_ADDR 0x90000000 +/* The first 256MB of SDRAM is reserved for firmware (Cortex M7) */ +#define PHYS_SDRAM_FW_RSVD SZ_256M +#define CFG_SYS_INIT_RAM_ADDR PHYS_SDRAM #define CFG_SYS_INIT_RAM_SIZE SZ_2M -#define CFG_SYS_SDRAM_BASE 0x90000000 -#define PHYS_SDRAM 0x90000000 -#define PHYS_SDRAM_SIZE (SZ_2G - SZ_256M) +#define CFG_SYS_SDRAM_BASE PHYS_SDRAM +#define PHYS_SDRAM (0x80000000 + PHYS_SDRAM_FW_RSVD) +#define PHYS_SDRAM_SIZE (SZ_2G - PHYS_SDRAM_FW_RSVD) #define PHYS_SDRAM_2_SIZE SZ_6G #endif -- 2.43.0
