Part Number: AM67A
Other Parts Discussed in Thread: TMDS64EVM, SK-AM64B
Hello,
We are working on adding Linux support for multiple custom boards based on the AM67A SoC, each having minor hardware variances. I noticed that several TI evaluation boards for different SoCs (like the AM64x) utilize the U-Boot multi-dtb-fit feature to handle board variants.
To avoid building and maintaining separate binaries for multiple boards, I want to implement this approach. We have an I2C EEPROM with a common data structure available on all boards, so the board detection logic was fairly straightforward to implement.
For the rest of the implementation—specifically packaging multiple DTBs and making adjustments inside the board initialization code—I have been using SoCs like the AM642 and J721S2 as a reference.
While the I2C read and board detection work perfectly, I hit a roadblock when trying to replace tiboot3.bin. The boot process always gets stuck during or immediately after dm_uninit.
Before I spend too much time debugging, I wanted to ask if there are any obvious mistakes in this approach, or if there is something platform-specific I need to consider for the AM67A regarding multi-dtb-fit in the initial boot phases.
Relevant changes made:
Inside j722s_init.c:
#ifdef CONFIG_SPL_OF_LIST
void do_dt_magic(void)
{
int ret, rescan, mmc_dev = -1;
static struct mmc *mmc;
/* Perform board detection */
do_board_detect();
/*
* Board detection has been done.
* Let us see if another dtb wouldn't be a better match
* for our board
*/
if (IS_ENABLED(CONFIG_CPU_V7R)) {
ret = fdtdec_resetup(&rescan);
printf("fdtdec_resetup returned %d, rescan = %d\n", ret, rescan);
if (!ret && rescan) {
printf("Rescanning devices after board detection...\n");
dm_uninit(); // HERE IT GET STUCK
dm_init_and_scan(true);
}
}
}
#endif
void board_init_f(ulong dummy)
{
int ret;
struct udevice *dev;
k3_spl_init();
#ifdef CONFIG_SPL_OF_LIST
do_dt_magic();
#endif
k3_mem_init();
setup_qos();
//...
}
On board level I implemented the do_board_detect and board_fit_config_name_match function:
void do_board_detect(void)
{
board_eeprom_detect();
switch (EEPROM_DATA->board) {
case BOARD_A:
printf("Board: Board A (HW rev %u.%u)\n",
EEPROM_DATA->hw_rev_major,
EEPROM_DATA->hw_rev_minor);
break;
case BOARD_B:
printf("Board: Board B (HW rev %u.%u)\n",
EEPROM_DATA->hw_rev_major,
EEPROM_DATA->hw_rev_minor);
break;
default:
printf("do_board_detect: unknown board variant\n");
break;
}
}
#if defined(CONFIG_SPL_LOAD_FIT)
int board_fit_config_name_match(const char *name)
{
printf("board_fit_config_name_match() called with name = %s\n", name);
if (!eeprom_was_detected()) {
printf("EEPROM not yet detected, deferring to FIT default config\n");
return -1;
}
printf("EEPROM detected, board type = %u\n", EEPROM_DATA->board);
switch (EEPROM_DATA->board) {
case BOARD_A:
if (!strcmp(name, "k3-am67a-r5-board-a") || !strcmp(name, "k3-am67a-board-a")) {
return 0;
}
break;
case BOARD_B:
if (!strcmp(name, "k3-am67a-r5-board-b") || !strcmp(name, "k3-am67a-board-b")) {
return 0;
}
break;
default:
printf("Unknown board variant, no matching DTB found\n");
break;
}
return -1;
}
#endif
Below also the boot logs.
U-Boot SPL 2026.01-00054-gd872d2b6be9b-dirty (Jun 23 2026 - 06:15:00 +0000)
SYSFW ABI: 4.0 (firmware rev 0x000b '11.2.8--v11.02.08 (Fancy Rat)')
Probing I2C bus 1 for EEPROM at address 0x53
Reading EEPROM from I2C bus 1 addr 0x53
EEPROM CRC: stored=0x44b9a992 computed=0x44b9a992
EEPROM manufacturerInfo: BOARD_B
Board: Board B (HW rev 0.2)
board_fit_config_name_match() called with name = k3-am67a-r5-board-a
EEPROM detected, board type = 2
board_fit_config_name_match() called with name = k3-am67a-r5-board-b
EEPROM detected, board type = 2
Selecting config 'k3-am67a-r5-board-b'
fdtdec_resetup returned 0, rescan = 1
Rescanning devices after board detection...
dm_uninit() called
// HERE IT GETS STUCKU-Boot SPL 2026.01-00054-gd872d2b6be9b-dirty (Jun 23 2026 - 09:23:48 +0000)
SYSFW ABI: 4.0 (firmware rev 0x000b '11.2.8--v11.02.08 (Fancy Rat)')
Probing I2C bus 1 for EEPROM at address 0x53
Reading EEPROM from I2C bus 1 addr 0x53
EEPROM CRC: stored=0xf0fbb19f computed=0xf0fbb19f
EEPROM manufacturerInfo: BOARD_B
Board: Board B (HW rev 0.2)
SPL initial stack usage: 17176 bytes
Trying to boot from MMC1
board_fit_config_name_match() called with name = k3-am67a-r5-board-a
EEPROM detected, board type = 2
board_fit_config_name_match() called with name = k3-am67a-r5-board-b
EEPROM detected, board type = 2
Selecting config 'k3-am67a-r5-board-b'
Authentication passed
Authentication passed
Authentication passed
init_env from device 9 not supported!
Authentication passed
Authentication passed
Starting ATF on ARM64 core...
NOTICE: BL31: v2.14.1(release):lts-v2.14.1
NOTICE: BL31: Built : 14:00:55, Jun 16 2026
I/TC:
I/TC: OP-TEE version: 4.9.0 (gcc version 14.2.0 (Debian 14.2.0-19)) #1 Tue Jun 16 13:59:35 UTC 2026 aarch64
I/TC: WARNING: This OP-TEE configuration might be insecure!
I/TC: WARNING: Please check optee.readthedocs.io/.../porting_guidelines.html
I/TC: Primary CPU initializing
I/TC: GIC redistributor base address not provided
I/TC: Assuming default GIC group status and modifier
I/TC: SYSFW ABI: 4.0 (firmware rev 0x000b '11.2.8--v11.02.08 (Fancy Rat)')
I/TC: Activated SA2UL device
I/TC: Enabled firewalls for SA2UL TRNG device
I/TC: EIP76D TRNG initialized
I/TC: SA2UL Drivers initialized
I/TC: HUK Initialized
I/TC: Disabling output console
U-Boot SPL 2026.01-00054-gd872d2b6be9b-dirty (Jun 23 2026 - 06:01:11 +0000)
SYSFW ABI: 4.0 (firmware rev 0x000b '11.2.8--v11.02.08 (Fancy Rat)')
DM ABI: 3.0 (firmware ver 0x000b 'MSDK.11.01.00.05--v11.01.09' patch_ver: 9)
Probing I2C bus 1 for EEPROM at address 0x53
Reading EEPROM from I2C bus 1 addr 0x53
EEPROM CRC: stored=0x44b9a992 computed=0x44b9a992
EEPROM manufacturerInfo: BOARD_B
Board: Board B (HW rev 0.2)
Trying to boot from MMC1
board_fit_config_name_match() called with name = k3-am67a-r5-board-a
EEPROM detected, board type = 2
board_fit_config_name_match() called with name = k3-am67a-r5-board-b
EEPROM detected, board type = 2
Selecting config 'k3-am67a-r5-board-b'
Authentication passed
Authentication passed
U-Boot 2026.01-00054-gd872d2b6be9b-dirty (Jun 23 2026 - 06:01:11 +0000)
SoC: J722S SR1.0 HS-FS
Model: Board B
DRAM: 2 GiB (total 4 GiB)
Core: 80 devices, 28 uclasses, devicetree: separate
MMC: mmc@fa10000: 0, mmc@fa00000: 1
Loading Environment from MMC... Reading from MMC(0)... OK
In: serial@2800000
Out: serial@2800000
Err: serial@2800000
Probing I2C bus 1 for EEPROM at address 0x53
Reading EEPROM from I2C bus 1 addr 0x53
EEPROM CRC: stored=0x44b9a992 computed=0x44b9a992
EEPROM manufacturerInfo: BOARD_B
Board: Board B (HW rev 0.2)
Net: No ethernet found.
Press SPACE to abort autoboot in 2 secondsThank you!
Martin
