The difference between TZDRAM and TZRAM

When I looked up the ATF code, I found that Tegra defines two macros:
1.’/atf_src/arm-trusted-firmware/plat/nvidia/tegra/include/t186/tegra_def.h’, the file defines the base address and size of TZRAM, the base address is 0x30000000 and the size is 256KB;
2.’/atf_src/arm-trusted-firmware/plat/nvidia/tegra/include/platform_def.h’, the file defines the size and end address of TZDRAM, the size is 4MB, but the base address of TZDRAM is not given;
May I ask:

  1. What is the difference between TZDRAM and TZRAM? Personally, TZDRAM is an area divided by MC in DRAM (off-chip); TZRAM is an area in on-chip memory.
  2. Where should I find the base address of TZDRAM?


hello fanyangyf688,

it’s bootloader to allocate a dedicated carveout, TZ-DRAM, to run a secure OS.
once a channel is configured as TrustZone, it cannot be used for a non-TrustZone process
please access TX2 Technical Reference Manual,
you may also refer to [19.4.4 TZ Bit Support in Push-Buffer Mechanism] for more details.

thanks for your reply! but,
I just want to know the specific configuration of TZDRAM in TX2 (such as starting physical address and ending physical address), I don’t know where to find this configuration.

hello fanyangyf688,

the TZ-DRAM base address is included in the aft makefiles,
for example,

# platform settings
TZDRAM_BASE                             := 0x30000000
$(eval $(call add_define,TZDRAM_BASE))

this base address of TZ-DRAM were different according to platforms,
it’s 0x40000000; for Jetson Xavier NX, Jetson AGX Xavier series,
it’s 0x30000000; for Jetson TX2 series devices,
it’s 0xff800000; for Jetson Nano, Jetson TX1 series devices,

thanks for your reply!
I also found TZDRAM_BASE, as you said, the value is ‘0x3000_0000’.
But the question is, the memory base address of DRAM is ‘TEGRA_DRAM_BASE=0x8000_0000’, why is TZDRAM_BASE not in the memory range of DRAM?
In addition, ‘TEGRA_TZRAM_BASE=0x3000_0000’, does this mean that both TZDRAM and TZRAM are in the on-chip RAM?

hello fanyangyf688,

please access TX2 Technical Reference Manual, and check Chapter-2.3 for the system address map.
you may also refer to [Table 117: Tegra Carveout Summary] for the details of TZ-DRAM and TZRAM.

but I still don’t know where TZDRAM is, I created a new topic, please refer to here.
thanks for your attention.