Introduction:
-------------
The AM65x family of SoCs is the first device family from K3 Multicore
SoC architecture, targeted for broad market and industrial control with
aim to meet the complex processing needs of modern embedded products.
The device is built over three domains, each containing specific processing
cores, voltage domains and peripherals:
1. Wake-up (WKUP) domain:
- Device Management and Security Controller (DMSC)
2. Microcontroller (MCU) domain:
- Dual Core ARM Cortex-R5F processor
3. MAIN domain:
- Quad core 64-bit ARM Cortex-A53
More info can be found in TRM: http://www.ti.com/lit/pdf/spruid7
Boot Flow:
----------
On AM65x family devices, ROM supports boot only via MCU(R5). This means that
bootloader has to run on R5 core. In order to meet this constraint, and for
the following reasons the boot flow is designed as mentioned:
1. Need to move away from R5 asap, so that we want to start *any*
firmware on the r5 cores like.... autosar can be loaded to receive CAN
response and other safety operations to be started. This operation is
very time critical and is applicable for all automotive use cases.
2. U-Boot on A53 should start other remotecores for various
applications. This should happen before running Linux.
3. In production boot flow, we might not like to use full u-boot,
instead use Flacon boot flow to reduce boot time.
+------------------------------------------------------------------------+
| DMSC | R5 | A53 |
+------------------------------------------------------------------------+
| +--------+ | | |
| | Reset | | | |
| +--------+ | | |
| : | | |
| +--------+ | +-----------+ | |
| | *ROM* |----------|-->| Reset rls | | |
| +--------+ | +-----------+ | |
| | | | : | |
| | ROM | | : | |
| |services| | : | |
| | | | +-------------+ | |
| | | | | *R5 ROM* | | |
| | | | +-------------+ | |
| | |<---------|---|Load and auth| | |
| | | | | tiboot3.bin | | |
| | | | +-------------+ | |
| | | | : | |
| | | | : | |
| | | | : | |
| | | | +-------------+ | |
| | | | | *R5 SPL* | | |
| | | | +-------------+ | |
| | | | | Load | | |
| | | | | sysfw.itb | | |
| | Start | | +-------------+ | |
| | System |<---------|---| Start | | |
| |Firmware| | | SYSFW | | |
| +--------+ | +-------------+ | |
| : | | | | |
| +---------+ | | Load | | |
| | *SYSFW* | | | system | | |
| +---------+ | | Config data | | |
| | |<--------|---| | | |
| | | | +-------------+ | |
| | | | | | | |
| | | | | DDR | | |
| | | | | config | | |
| | | | +-------------+ | |
| | | | | | | |
| | |<--------|---| Start A53 | | |
| | | | | and Reset | | |
| | | | +-------------+ | |
| | | | | +-----------+ |
| | |---------|-----------------------|---->| Reset rls | |
| | | | | +-----------+ |
| | DMSC | | | : |
| |Services | | | +-----------+ |
| | |<--------|-----------------------|---->|*ATF/OPTEE*| |
| | | | | +-----------+ |
| | | | | : |
| | | | | +-----------+ |
| | |<--------|-----------------------|---->| *A53 SPL* | |
| | | | | +-----------+ |
| | | | | | Load | |
| | | | | | u-boot.img| |
| | | | | +-----------+ |
| | | | | : |
| | | | | +-----------+ |
| | |<--------|-----------------------|---->| *U-Boot* | |
| | | | | +-----------+ |
| | | | | | prompt | |
| | | | | +-----------+ |
| +---------+ | | |
| | | |
+------------------------------------------------------------------------+
- Here DMSC acts as master and provides all the critical services. R5/A53
requests DMSC to get these services done as shown in the above diagram.
Sources:
--------
1. SYSFW:
Tree: git://git.ti.com/processor-firmware/system-firmware-image-gen.git
Branch: master
2. ATF:
Tree: https://github.com/ARM-software/arm-trusted-firmware.git
Branch: master
3. OPTEE:
Tree: https://github.com/OP-TEE/optee_os.git
Branch: master
4. U-Boot:
Tree: http://git.denx.de/u-boot.git
Branch: master
Build procedure:
----------------
1. SYSFW:
$ make CROSS_COMPILE=arm-linux-gnueabihf-
2. ATF:
$ make CROSS_COMPILE=aarch64-linux-gnu- ARCH=aarch64 PLAT=k3 TARGET_BOARD=generic SPD=opteed
3. OPTEE:
$ make PLATFORM=k3-am65x CFG_ARM64_core=y
4. U-Boot:
4.1. R5:
$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- am65x_evm_r5_defconfig O=/tmp/r5
$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- O=/tmp/r5
4.2. A53:
$ make ARCH=arm CROSS_COMPILE=aarch64-linux-gnu- am65x_evm_a53_defconfig O=/tmp/a53
$ make ARCH=arm CROSS_COMPILE=aarch64-linux-gnu- ATF=<path to ATF dir>/build/k3/generic/release/bl31.bin TEE=<path to OPTEE OS dir>/out/arm-plat-k3/core/tee-pager.bin O=/tmp/a53
Target Images
--------------
Copy the below images to an SD card and boot:
- sysfw.itb from step 1
- tiboot3.bin from step 4.1
- tispl.bin, u-boot.img from 4.2
Image formats:
--------------
- tiboot3.bin:
+-----------------------+
| X.509 |
| Certificate |
| +-------------------+ |
| | | |
| | R5 | |
| | u-boot-spl.bin | |
| | | |
| +-------------------+ |
| | | |
| | FIT header | |
| | +---------------+ | |
| | | | | |
| | | DTB 1...N | | |
| | +---------------+ | |
| +-------------------+ |
+-----------------------+
- tispl.bin
+-----------------------+
| |
| FIT HEADER |
| +-------------------+ |
| | | |
| | A53 ATF | |
| +-------------------+ |
| | | |
| | A53 OPTEE | |
| +-------------------+ |
| | | |
| | A53 SPL | |
| +-------------------+ |
| | | |
| | SPL DTB 1...N | |
| +-------------------+ |
+-----------------------+
- sysfw.itb
+-----------------------+
| |
| FIT HEADER |
| +-------------------+ |
| | | |
| | sysfw.bin | |
| +-------------------+ |
| | | |
| | board config | |
| +-------------------+ |
| | | |
| | PM config | |
| +-------------------+ |
| | | |
| | RM config | |
| +-------------------+ |
| | | |
| | Secure config | |
| +-------------------+ |
+-----------------------+
eMMC:
-----
ROM supports booting from eMMC from boot0 partition offset 0x0
Flashing images to eMMC:
The following commands can be used to download tiboot3.bin, tispl.bin,
u-boot.img, and sysfw.itb from an SD card and write them to the eMMC boot0
partition at respective addresses.
=> mmc dev 0 1
=> fatload mmc 1 ${loadaddr} tiboot3.bin
=> mmc write ${loadaddr} 0x0 0x400
=> fatload mmc 1 ${loadaddr} tispl.bin
=> mmc write ${loadaddr} 0x400 0x1000
=> fatload mmc 1 ${loadaddr} u-boot.img
=> mmc write ${loadaddr} 0x1400 0x2000
=> fatload mmc 1 ${loadaddr} sysfw.itb
=> mmc write ${loadaddr} 0x3600 0x800
To give the ROM access to the boot partition, the following commands must be
used for the first time:
=> mmc partconf 0 1 1 1
=> mmc bootbus 0 1 0 0
To create a software partition for the rootfs, the following command can be
used:
=> gpt write mmc 0 ${partitions}
eMMC layout:
boot0 partition (8 MB) user partition
0x0+----------------------------------+ 0x0+-------------------------+
| tiboot3.bin (512 KB) | | |
0x400+----------------------------------+ | |
| tispl.bin (2 MB) | | |
0x1400+----------------------------------+ | rootfs |
| u-boot.img (4 MB) | | |
0x3400+----------------------------------+ | |
| environment (128 KB) | | |
0x3500+----------------------------------+ | |
| backup environment (128 KB) | | |
0x3600+----------------------------------+ | |
| sysfw (1 MB) | | |
0x3E00+----------------------------------+ +-------------------------+
Kernel image and DT are expected to be present in the /boot folder of rootfs.
To boot kernel from eMMC, use the following commands:
=> setenv mmcdev 0
=> setenv bootpart 0
=> boot
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