A38x: Broken Linux kernel booting over UART

Hello!
Current U-Boot master has broken booting of Linux kernel over UART on A38x.
After transferring image over UART it just prints:
CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
It resets board and does not boot kernel. Note that I'm trying to boot recent 5.15 kernel image, not something old.
I did git bisect and it found following commit which broke booting:
9774462e34faaa64a91eb9c68b438a52d22bba6a is the first bad commit commit 9774462e34faaa64a91eb9c68b438a52d22bba6a Author: Tom Rini trini@konsulko.com Date: Mon Aug 30 09:16:30 2021 -0400
arm: Disable ATAGs support
Prior this commit booting working fine.
Do you have any idea what is with above commit? Or any hints?

On Mon, Oct 11, 2021 at 12:13:29PM +0200, Pali Rohár wrote:
Hello!
Current U-Boot master has broken booting of Linux kernel over UART on A38x.
After transferring image over UART it just prints:
CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
It resets board and does not boot kernel. Note that I'm trying to boot recent 5.15 kernel image, not something old.
I did git bisect and it found following commit which broke booting:
9774462e34faaa64a91eb9c68b438a52d22bba6a is the first bad commit commit 9774462e34faaa64a91eb9c68b438a52d22bba6a Author: Tom Rini trini@konsulko.com Date: Mon Aug 30 09:16:30 2021 -0400
arm: Disable ATAGs support
Prior this commit booting working fine.
Do you have any idea what is with above commit? Or any hints?
Can you provide the full log of what you're doing? And what's in that image you're passing, exactly? Thanks.

On Monday 11 October 2021 10:03:21 Tom Rini wrote:
On Mon, Oct 11, 2021 at 12:13:29PM +0200, Pali Rohár wrote:
Hello!
Current U-Boot master has broken booting of Linux kernel over UART on A38x.
After transferring image over UART it just prints:
CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
It resets board and does not boot kernel. Note that I'm trying to boot recent 5.15 kernel image, not something old.
I did git bisect and it found following commit which broke booting:
9774462e34faaa64a91eb9c68b438a52d22bba6a is the first bad commit commit 9774462e34faaa64a91eb9c68b438a52d22bba6a Author: Tom Rini trini@konsulko.com Date: Mon Aug 30 09:16:30 2021 -0400
arm: Disable ATAGs support
Prior this commit booting working fine.
Do you have any idea what is with above commit? Or any hints?
Can you provide the full log of what you're doing? And what's in that image you're passing, exactly? Thanks.
Here is full log:
$ make CROSS_COMPILE=arm-linux-gnueabihf- turris_omnia_defconfig ... $ make CROSS_COMPILE=arm-linux-gnueabihf- -j8 ... $ ./tools/kwboot -b ./u-boot-spl.kwb -B 5200000 -t /dev/ttyUSB0 Patching image boot signature to UART Injecting binary header code for changing baudrate to 5200000 Bd Injecting code for changing baudrate back Aligning image header to Xmodem block size Sending boot message. Please reboot the target...- Waiting 2s and flushing tty Sending boot image header (115072 bytes)... 0 % [......................................................................] ... 93 % [........................................................... ] Done
U-Boot SPL 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200) High speed PHY - Version: 2.0 MiniPCIe/mSATA card detection... MiniPCIe Detected Device ID 6820 board SerDes lanes topology details: | Lane # | Speed | Type | -------------------------------- | 0 | 5 | PCIe0 | | 1 | 5 | USB3 HOST0 | | 2 | 5 | PCIe1 | | 3 | 5 | USB3 HOST1 | | 4 | 5 | PCIe2 | | 5 | 0 | SGMII2 | -------------------------------- High speed PHY - Ended Successfully mv_ddr: 14.0.0 DDR3 Training Sequence - Switching XBAR Window to FastPath Window mv_ddr: completed successfully Disabling MCU watchdog... disabled Trying to boot from BOOTROM Returning to BootROM (return address 0xffff05c4)...
Changing baudrate to 5200000 Bd
Sending boot image data (747780 bytes)... 0 % [......................................................................] ... 99 % [................................. ] Done Finishing transfer
Changing baudrate back to 115200 Bd
[Type Ctrl-\ + c to quit]
U-Boot 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200)
SoC: MV88F6820-A0 at 1600 MHz DRAM: 2 GiB (800 MHz, 32-bit, 2T, ECC not enabled) WDT: Started watchdog@20300 with servicing (60s timeout) MMC: mv_sdh: 0 Loading Environment from SPIFlash... SF: Detected s25fl164k with page size 256 Bytes, erase size 4 KiB, total 8 MiB OK Model: Turris Omnia Turris Omnia: RAM size: 2048 MiB Serial Number: 0000000B00007B3C Regdomain set to ** Net: eth0: ethernet@70000, eth1: ethernet@30000, eth2: ethernet@34000 =>
$ kermit C-Kermit>set line /dev/ttyUSB0 C-Kermit>set speed 115200 C-Kermit>set carrier-watch off C-Kermit>connect Connecting to /dev/ttyUSB0, speed 115200 Escape character: Ctrl-\ (ASCII 28, FS): enabled Type the escape character followed by C to get back, or followed by ? to see other options. ----------------------------------------------------
=> echo $uart_boot loadb $kernel_addr_r 5200000 && part uuid mmc 0:1 partuuid && setenv bootargs earlyprintk rootwait console=ttyS0,115200 rootfstype=btrfs root=PARTUUID=${partuuid} rootflags=commit=5,subvol=@ rw cfg80211.freg=${regdomain} && bootz ${kernel_addr_r} => run uart_boot ## Switch baudrate to 5200000 bps and press ENTER ... C-Kermit>set speed 5200000 ?No keywords match - 5200000 (,Transmission rate for /dev/ttyUSB0 (bits per second))
?SET SPEED fails, speed is 5260273 C-Kermit>send /tmp/kernel C-Kermit>set speed 115200 /dev/ttyUSB0, 115200 bps C-Kermit>connect CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 ## Switch baudrate to 115200 bps and press ESC ... Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...

On Mon, Oct 11, 2021 at 04:25:48PM +0200, Pali Rohár wrote:
On Monday 11 October 2021 10:03:21 Tom Rini wrote:
On Mon, Oct 11, 2021 at 12:13:29PM +0200, Pali Rohár wrote:
Hello!
Current U-Boot master has broken booting of Linux kernel over UART on A38x.
After transferring image over UART it just prints:
CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
It resets board and does not boot kernel. Note that I'm trying to boot recent 5.15 kernel image, not something old.
I did git bisect and it found following commit which broke booting:
9774462e34faaa64a91eb9c68b438a52d22bba6a is the first bad commit commit 9774462e34faaa64a91eb9c68b438a52d22bba6a Author: Tom Rini trini@konsulko.com Date: Mon Aug 30 09:16:30 2021 -0400
arm: Disable ATAGs support
Prior this commit booting working fine.
Do you have any idea what is with above commit? Or any hints?
Can you provide the full log of what you're doing? And what's in that image you're passing, exactly? Thanks.
Here is full log:
$ make CROSS_COMPILE=arm-linux-gnueabihf- turris_omnia_defconfig ... $ make CROSS_COMPILE=arm-linux-gnueabihf- -j8 ... $ ./tools/kwboot -b ./u-boot-spl.kwb -B 5200000 -t /dev/ttyUSB0 Patching image boot signature to UART Injecting binary header code for changing baudrate to 5200000 Bd Injecting code for changing baudrate back Aligning image header to Xmodem block size Sending boot message. Please reboot the target...- Waiting 2s and flushing tty Sending boot image header (115072 bytes)... 0 % [......................................................................] ... 93 % [........................................................... ] Done
U-Boot SPL 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200) High speed PHY - Version: 2.0 MiniPCIe/mSATA card detection... MiniPCIe Detected Device ID 6820 board SerDes lanes topology details: | Lane # | Speed | Type |
| 0 | 5 | PCIe0 | | 1 | 5 | USB3 HOST0 | | 2 | 5 | PCIe1 | | 3 | 5 | USB3 HOST1 | | 4 | 5 | PCIe2 | | 5 | 0 | SGMII2 |
High speed PHY - Ended Successfully mv_ddr: 14.0.0 DDR3 Training Sequence - Switching XBAR Window to FastPath Window mv_ddr: completed successfully Disabling MCU watchdog... disabled Trying to boot from BOOTROM Returning to BootROM (return address 0xffff05c4)...
Changing baudrate to 5200000 Bd
Sending boot image data (747780 bytes)... 0 % [......................................................................] ... 99 % [................................. ] Done Finishing transfer
Changing baudrate back to 115200 Bd
[Type Ctrl-\ + c to quit]
U-Boot 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200)
SoC: MV88F6820-A0 at 1600 MHz DRAM: 2 GiB (800 MHz, 32-bit, 2T, ECC not enabled) WDT: Started watchdog@20300 with servicing (60s timeout) MMC: mv_sdh: 0 Loading Environment from SPIFlash... SF: Detected s25fl164k with page size 256 Bytes, erase size 4 KiB, total 8 MiB OK Model: Turris Omnia Turris Omnia: RAM size: 2048 MiB Serial Number: 0000000B00007B3C Regdomain set to ** Net: eth0: ethernet@70000, eth1: ethernet@30000, eth2: ethernet@34000 =>
$ kermit C-Kermit>set line /dev/ttyUSB0 C-Kermit>set speed 115200 C-Kermit>set carrier-watch off C-Kermit>connect Connecting to /dev/ttyUSB0, speed 115200 Escape character: Ctrl-\ (ASCII 28, FS): enabled Type the escape character followed by C to get back, or followed by ? to see other options.
=> echo $uart_boot loadb $kernel_addr_r 5200000 && part uuid mmc 0:1 partuuid && setenv bootargs earlyprintk rootwait console=ttyS0,115200 rootfstype=btrfs root=PARTUUID=${partuuid} rootflags=commit=5,subvol=@ rw cfg80211.freg=${regdomain} && bootz ${kernel_addr_r} => run uart_boot ## Switch baudrate to 5200000 bps and press ENTER ... C-Kermit>set speed 5200000 ?No keywords match - 5200000 (,Transmission rate for /dev/ttyUSB0 (bits per second))
?SET SPEED fails, speed is 5260273 C-Kermit>send /tmp/kernel C-Kermit>set speed 115200 /dev/ttyUSB0, 115200 bps C-Kermit>connect CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 ## Switch baudrate to 115200 bps and press ESC ... Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
OK, and is /tmp/kernel something with an appended dtb then?

On Monday 11 October 2021 10:32:22 Tom Rini wrote:
On Mon, Oct 11, 2021 at 04:25:48PM +0200, Pali Rohár wrote:
On Monday 11 October 2021 10:03:21 Tom Rini wrote:
On Mon, Oct 11, 2021 at 12:13:29PM +0200, Pali Rohár wrote:
Hello!
Current U-Boot master has broken booting of Linux kernel over UART on A38x.
After transferring image over UART it just prints:
CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
It resets board and does not boot kernel. Note that I'm trying to boot recent 5.15 kernel image, not something old.
I did git bisect and it found following commit which broke booting:
9774462e34faaa64a91eb9c68b438a52d22bba6a is the first bad commit commit 9774462e34faaa64a91eb9c68b438a52d22bba6a Author: Tom Rini trini@konsulko.com Date: Mon Aug 30 09:16:30 2021 -0400
arm: Disable ATAGs support
Prior this commit booting working fine.
Do you have any idea what is with above commit? Or any hints?
Can you provide the full log of what you're doing? And what's in that image you're passing, exactly? Thanks.
Here is full log:
$ make CROSS_COMPILE=arm-linux-gnueabihf- turris_omnia_defconfig ... $ make CROSS_COMPILE=arm-linux-gnueabihf- -j8 ... $ ./tools/kwboot -b ./u-boot-spl.kwb -B 5200000 -t /dev/ttyUSB0 Patching image boot signature to UART Injecting binary header code for changing baudrate to 5200000 Bd Injecting code for changing baudrate back Aligning image header to Xmodem block size Sending boot message. Please reboot the target...- Waiting 2s and flushing tty Sending boot image header (115072 bytes)... 0 % [......................................................................] ... 93 % [........................................................... ] Done
U-Boot SPL 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200) High speed PHY - Version: 2.0 MiniPCIe/mSATA card detection... MiniPCIe Detected Device ID 6820 board SerDes lanes topology details: | Lane # | Speed | Type |
| 0 | 5 | PCIe0 | | 1 | 5 | USB3 HOST0 | | 2 | 5 | PCIe1 | | 3 | 5 | USB3 HOST1 | | 4 | 5 | PCIe2 | | 5 | 0 | SGMII2 |
High speed PHY - Ended Successfully mv_ddr: 14.0.0 DDR3 Training Sequence - Switching XBAR Window to FastPath Window mv_ddr: completed successfully Disabling MCU watchdog... disabled Trying to boot from BOOTROM Returning to BootROM (return address 0xffff05c4)...
Changing baudrate to 5200000 Bd
Sending boot image data (747780 bytes)... 0 % [......................................................................] ... 99 % [................................. ] Done Finishing transfer
Changing baudrate back to 115200 Bd
[Type Ctrl-\ + c to quit]
U-Boot 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200)
SoC: MV88F6820-A0 at 1600 MHz DRAM: 2 GiB (800 MHz, 32-bit, 2T, ECC not enabled) WDT: Started watchdog@20300 with servicing (60s timeout) MMC: mv_sdh: 0 Loading Environment from SPIFlash... SF: Detected s25fl164k with page size 256 Bytes, erase size 4 KiB, total 8 MiB OK Model: Turris Omnia Turris Omnia: RAM size: 2048 MiB Serial Number: 0000000B00007B3C Regdomain set to ** Net: eth0: ethernet@70000, eth1: ethernet@30000, eth2: ethernet@34000 =>
$ kermit C-Kermit>set line /dev/ttyUSB0 C-Kermit>set speed 115200 C-Kermit>set carrier-watch off C-Kermit>connect Connecting to /dev/ttyUSB0, speed 115200 Escape character: Ctrl-\ (ASCII 28, FS): enabled Type the escape character followed by C to get back, or followed by ? to see other options.
=> echo $uart_boot loadb $kernel_addr_r 5200000 && part uuid mmc 0:1 partuuid && setenv bootargs earlyprintk rootwait console=ttyS0,115200 rootfstype=btrfs root=PARTUUID=${partuuid} rootflags=commit=5,subvol=@ rw cfg80211.freg=${regdomain} && bootz ${kernel_addr_r} => run uart_boot ## Switch baudrate to 5200000 bps and press ENTER ... C-Kermit>set speed 5200000 ?No keywords match - 5200000 (,Transmission rate for /dev/ttyUSB0 (bits per second))
?SET SPEED fails, speed is 5260273 C-Kermit>send /tmp/kernel C-Kermit>set speed 115200 /dev/ttyUSB0, 115200 bps C-Kermit>connect CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 ## Switch baudrate to 115200 bps and press ESC ... Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
OK, and is /tmp/kernel something with an appended dtb then?
Yes, single image suitable for single kermit UART transfer: cat arch/arm/boot/zImage arch/arm/boot/dts/armada-385-turris-omnia.dtb > /tmp/kernel

On Mon, Oct 11, 2021 at 04:33:44PM +0200, Pali Rohár wrote:
On Monday 11 October 2021 10:32:22 Tom Rini wrote:
On Mon, Oct 11, 2021 at 04:25:48PM +0200, Pali Rohár wrote:
On Monday 11 October 2021 10:03:21 Tom Rini wrote:
On Mon, Oct 11, 2021 at 12:13:29PM +0200, Pali Rohár wrote:
Hello!
Current U-Boot master has broken booting of Linux kernel over UART on A38x.
After transferring image over UART it just prints:
CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
It resets board and does not boot kernel. Note that I'm trying to boot recent 5.15 kernel image, not something old.
I did git bisect and it found following commit which broke booting:
9774462e34faaa64a91eb9c68b438a52d22bba6a is the first bad commit commit 9774462e34faaa64a91eb9c68b438a52d22bba6a Author: Tom Rini trini@konsulko.com Date: Mon Aug 30 09:16:30 2021 -0400
arm: Disable ATAGs support
Prior this commit booting working fine.
Do you have any idea what is with above commit? Or any hints?
Can you provide the full log of what you're doing? And what's in that image you're passing, exactly? Thanks.
Here is full log:
$ make CROSS_COMPILE=arm-linux-gnueabihf- turris_omnia_defconfig ... $ make CROSS_COMPILE=arm-linux-gnueabihf- -j8 ... $ ./tools/kwboot -b ./u-boot-spl.kwb -B 5200000 -t /dev/ttyUSB0 Patching image boot signature to UART Injecting binary header code for changing baudrate to 5200000 Bd Injecting code for changing baudrate back Aligning image header to Xmodem block size Sending boot message. Please reboot the target...- Waiting 2s and flushing tty Sending boot image header (115072 bytes)... 0 % [......................................................................] ... 93 % [........................................................... ] Done
U-Boot SPL 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200) High speed PHY - Version: 2.0 MiniPCIe/mSATA card detection... MiniPCIe Detected Device ID 6820 board SerDes lanes topology details: | Lane # | Speed | Type |
| 0 | 5 | PCIe0 | | 1 | 5 | USB3 HOST0 | | 2 | 5 | PCIe1 | | 3 | 5 | USB3 HOST1 | | 4 | 5 | PCIe2 | | 5 | 0 | SGMII2 |
High speed PHY - Ended Successfully mv_ddr: 14.0.0 DDR3 Training Sequence - Switching XBAR Window to FastPath Window mv_ddr: completed successfully Disabling MCU watchdog... disabled Trying to boot from BOOTROM Returning to BootROM (return address 0xffff05c4)...
Changing baudrate to 5200000 Bd
Sending boot image data (747780 bytes)... 0 % [......................................................................] ... 99 % [................................. ] Done Finishing transfer
Changing baudrate back to 115200 Bd
[Type Ctrl-\ + c to quit]
U-Boot 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200)
SoC: MV88F6820-A0 at 1600 MHz DRAM: 2 GiB (800 MHz, 32-bit, 2T, ECC not enabled) WDT: Started watchdog@20300 with servicing (60s timeout) MMC: mv_sdh: 0 Loading Environment from SPIFlash... SF: Detected s25fl164k with page size 256 Bytes, erase size 4 KiB, total 8 MiB OK Model: Turris Omnia Turris Omnia: RAM size: 2048 MiB Serial Number: 0000000B00007B3C Regdomain set to ** Net: eth0: ethernet@70000, eth1: ethernet@30000, eth2: ethernet@34000 =>
$ kermit C-Kermit>set line /dev/ttyUSB0 C-Kermit>set speed 115200 C-Kermit>set carrier-watch off C-Kermit>connect Connecting to /dev/ttyUSB0, speed 115200 Escape character: Ctrl-\ (ASCII 28, FS): enabled Type the escape character followed by C to get back, or followed by ? to see other options.
=> echo $uart_boot loadb $kernel_addr_r 5200000 && part uuid mmc 0:1 partuuid && setenv bootargs earlyprintk rootwait console=ttyS0,115200 rootfstype=btrfs root=PARTUUID=${partuuid} rootflags=commit=5,subvol=@ rw cfg80211.freg=${regdomain} && bootz ${kernel_addr_r} => run uart_boot ## Switch baudrate to 5200000 bps and press ENTER ... C-Kermit>set speed 5200000 ?No keywords match - 5200000 (,Transmission rate for /dev/ttyUSB0 (bits per second))
?SET SPEED fails, speed is 5260273 C-Kermit>send /tmp/kernel C-Kermit>set speed 115200 /dev/ttyUSB0, 115200 bps C-Kermit>connect CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 ## Switch baudrate to 115200 bps and press ESC ... Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
OK, and is /tmp/kernel something with an appended dtb then?
Yes, single image suitable for single kermit UART transfer: cat arch/arm/boot/zImage arch/arm/boot/dts/armada-385-turris-omnia.dtb > /tmp/kernel
Well, OK, there we go. That's what you need to figure out how to fix booting of. You're hitting the panic in arch/arm/lib/bootm.c and need to make sure that (a) we do whatever is needed for appended dtb to be found by the kernel still/again and (b) check that ourselves, before panic or not, in that case. Before this was probably enabling ATAGs, but that wasn't (I think? I forget the magic behind appended dtb as it's been a while) actually used by Linux, just by U-Boot to not panic at that point.

On Monday 11 October 2021 10:45:44 Tom Rini wrote:
On Mon, Oct 11, 2021 at 04:33:44PM +0200, Pali Rohár wrote:
On Monday 11 October 2021 10:32:22 Tom Rini wrote:
On Mon, Oct 11, 2021 at 04:25:48PM +0200, Pali Rohár wrote:
On Monday 11 October 2021 10:03:21 Tom Rini wrote:
On Mon, Oct 11, 2021 at 12:13:29PM +0200, Pali Rohár wrote:
Hello!
Current U-Boot master has broken booting of Linux kernel over UART on A38x.
After transferring image over UART it just prints:
CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
It resets board and does not boot kernel. Note that I'm trying to boot recent 5.15 kernel image, not something old.
I did git bisect and it found following commit which broke booting:
9774462e34faaa64a91eb9c68b438a52d22bba6a is the first bad commit commit 9774462e34faaa64a91eb9c68b438a52d22bba6a Author: Tom Rini trini@konsulko.com Date: Mon Aug 30 09:16:30 2021 -0400
arm: Disable ATAGs support
Prior this commit booting working fine.
Do you have any idea what is with above commit? Or any hints?
Can you provide the full log of what you're doing? And what's in that image you're passing, exactly? Thanks.
Here is full log:
$ make CROSS_COMPILE=arm-linux-gnueabihf- turris_omnia_defconfig ... $ make CROSS_COMPILE=arm-linux-gnueabihf- -j8 ... $ ./tools/kwboot -b ./u-boot-spl.kwb -B 5200000 -t /dev/ttyUSB0 Patching image boot signature to UART Injecting binary header code for changing baudrate to 5200000 Bd Injecting code for changing baudrate back Aligning image header to Xmodem block size Sending boot message. Please reboot the target...- Waiting 2s and flushing tty Sending boot image header (115072 bytes)... 0 % [......................................................................] ... 93 % [........................................................... ] Done
U-Boot SPL 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200) High speed PHY - Version: 2.0 MiniPCIe/mSATA card detection... MiniPCIe Detected Device ID 6820 board SerDes lanes topology details: | Lane # | Speed | Type |
| 0 | 5 | PCIe0 | | 1 | 5 | USB3 HOST0 | | 2 | 5 | PCIe1 | | 3 | 5 | USB3 HOST1 | | 4 | 5 | PCIe2 | | 5 | 0 | SGMII2 |
High speed PHY - Ended Successfully mv_ddr: 14.0.0 DDR3 Training Sequence - Switching XBAR Window to FastPath Window mv_ddr: completed successfully Disabling MCU watchdog... disabled Trying to boot from BOOTROM Returning to BootROM (return address 0xffff05c4)...
Changing baudrate to 5200000 Bd
Sending boot image data (747780 bytes)... 0 % [......................................................................] ... 99 % [................................. ] Done Finishing transfer
Changing baudrate back to 115200 Bd
[Type Ctrl-\ + c to quit]
U-Boot 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200)
SoC: MV88F6820-A0 at 1600 MHz DRAM: 2 GiB (800 MHz, 32-bit, 2T, ECC not enabled) WDT: Started watchdog@20300 with servicing (60s timeout) MMC: mv_sdh: 0 Loading Environment from SPIFlash... SF: Detected s25fl164k with page size 256 Bytes, erase size 4 KiB, total 8 MiB OK Model: Turris Omnia Turris Omnia: RAM size: 2048 MiB Serial Number: 0000000B00007B3C Regdomain set to ** Net: eth0: ethernet@70000, eth1: ethernet@30000, eth2: ethernet@34000 =>
$ kermit C-Kermit>set line /dev/ttyUSB0 C-Kermit>set speed 115200 C-Kermit>set carrier-watch off C-Kermit>connect Connecting to /dev/ttyUSB0, speed 115200 Escape character: Ctrl-\ (ASCII 28, FS): enabled Type the escape character followed by C to get back, or followed by ? to see other options.
=> echo $uart_boot loadb $kernel_addr_r 5200000 && part uuid mmc 0:1 partuuid && setenv bootargs earlyprintk rootwait console=ttyS0,115200 rootfstype=btrfs root=PARTUUID=${partuuid} rootflags=commit=5,subvol=@ rw cfg80211.freg=${regdomain} && bootz ${kernel_addr_r} => run uart_boot ## Switch baudrate to 5200000 bps and press ENTER ... C-Kermit>set speed 5200000 ?No keywords match - 5200000 (,Transmission rate for /dev/ttyUSB0 (bits per second))
?SET SPEED fails, speed is 5260273 C-Kermit>send /tmp/kernel C-Kermit>set speed 115200 /dev/ttyUSB0, 115200 bps C-Kermit>connect CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 ## Switch baudrate to 115200 bps and press ESC ... Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
OK, and is /tmp/kernel something with an appended dtb then?
Yes, single image suitable for single kermit UART transfer: cat arch/arm/boot/zImage arch/arm/boot/dts/armada-385-turris-omnia.dtb > /tmp/kernel
Well, OK, there we go. That's what you need to figure out how to fix booting of. You're hitting the panic in arch/arm/lib/bootm.c and need to make sure that (a) we do whatever is needed for appended dtb to be found by the kernel still/again and (b) check that ourselves, before panic or not, in that case. Before this was probably enabling ATAGs, but that wasn't (I think? I forget the magic behind appended dtb as it's been a while) actually used by Linux, just by U-Boot to not panic at that point.
Ok, thanks for hints. So seems that som unrelated code path via atags was used even for DTS booting. I also do not remember details. I will try to debug it...

On Monday 11 October 2021 17:49:05 Pali Rohár wrote:
On Monday 11 October 2021 10:45:44 Tom Rini wrote:
On Mon, Oct 11, 2021 at 04:33:44PM +0200, Pali Rohár wrote:
On Monday 11 October 2021 10:32:22 Tom Rini wrote:
On Mon, Oct 11, 2021 at 04:25:48PM +0200, Pali Rohár wrote:
On Monday 11 October 2021 10:03:21 Tom Rini wrote:
On Mon, Oct 11, 2021 at 12:13:29PM +0200, Pali Rohár wrote:
> Hello! > > Current U-Boot master has broken booting of Linux kernel over UART on > A38x. > > After transferring image over UART it just prints: > > CACHE: Misaligned operation at range [01000000, 014e5d96] > ## Total Size = 0x004e5d96 = 5135766 Bytes > ## Start Addr = 0x01000000 > Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] > FDT and ATAGS support not compiled in > > resetting ... > > It resets board and does not boot kernel. Note that I'm trying to boot > recent 5.15 kernel image, not something old. > > I did git bisect and it found following commit which broke booting: > > 9774462e34faaa64a91eb9c68b438a52d22bba6a is the first bad commit > commit 9774462e34faaa64a91eb9c68b438a52d22bba6a > Author: Tom Rini trini@konsulko.com > Date: Mon Aug 30 09:16:30 2021 -0400 > > arm: Disable ATAGs support > > Prior this commit booting working fine. > > Do you have any idea what is with above commit? Or any hints?
Can you provide the full log of what you're doing? And what's in that image you're passing, exactly? Thanks.
Here is full log:
$ make CROSS_COMPILE=arm-linux-gnueabihf- turris_omnia_defconfig ... $ make CROSS_COMPILE=arm-linux-gnueabihf- -j8 ... $ ./tools/kwboot -b ./u-boot-spl.kwb -B 5200000 -t /dev/ttyUSB0 Patching image boot signature to UART Injecting binary header code for changing baudrate to 5200000 Bd Injecting code for changing baudrate back Aligning image header to Xmodem block size Sending boot message. Please reboot the target...- Waiting 2s and flushing tty Sending boot image header (115072 bytes)... 0 % [......................................................................] ... 93 % [........................................................... ] Done
U-Boot SPL 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200) High speed PHY - Version: 2.0 MiniPCIe/mSATA card detection... MiniPCIe Detected Device ID 6820 board SerDes lanes topology details: | Lane # | Speed | Type |
| 0 | 5 | PCIe0 | | 1 | 5 | USB3 HOST0 | | 2 | 5 | PCIe1 | | 3 | 5 | USB3 HOST1 | | 4 | 5 | PCIe2 | | 5 | 0 | SGMII2 |
High speed PHY - Ended Successfully mv_ddr: 14.0.0 DDR3 Training Sequence - Switching XBAR Window to FastPath Window mv_ddr: completed successfully Disabling MCU watchdog... disabled Trying to boot from BOOTROM Returning to BootROM (return address 0xffff05c4)...
Changing baudrate to 5200000 Bd
Sending boot image data (747780 bytes)... 0 % [......................................................................] ... 99 % [................................. ] Done Finishing transfer
Changing baudrate back to 115200 Bd
[Type Ctrl-\ + c to quit]
U-Boot 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200)
SoC: MV88F6820-A0 at 1600 MHz DRAM: 2 GiB (800 MHz, 32-bit, 2T, ECC not enabled) WDT: Started watchdog@20300 with servicing (60s timeout) MMC: mv_sdh: 0 Loading Environment from SPIFlash... SF: Detected s25fl164k with page size 256 Bytes, erase size 4 KiB, total 8 MiB OK Model: Turris Omnia Turris Omnia: RAM size: 2048 MiB Serial Number: 0000000B00007B3C Regdomain set to ** Net: eth0: ethernet@70000, eth1: ethernet@30000, eth2: ethernet@34000 =>
$ kermit C-Kermit>set line /dev/ttyUSB0 C-Kermit>set speed 115200 C-Kermit>set carrier-watch off C-Kermit>connect Connecting to /dev/ttyUSB0, speed 115200 Escape character: Ctrl-\ (ASCII 28, FS): enabled Type the escape character followed by C to get back, or followed by ? to see other options.
=> echo $uart_boot loadb $kernel_addr_r 5200000 && part uuid mmc 0:1 partuuid && setenv bootargs earlyprintk rootwait console=ttyS0,115200 rootfstype=btrfs root=PARTUUID=${partuuid} rootflags=commit=5,subvol=@ rw cfg80211.freg=${regdomain} && bootz ${kernel_addr_r} => run uart_boot ## Switch baudrate to 5200000 bps and press ENTER ... C-Kermit>set speed 5200000 ?No keywords match - 5200000 (,Transmission rate for /dev/ttyUSB0 (bits per second))
?SET SPEED fails, speed is 5260273 C-Kermit>send /tmp/kernel C-Kermit>set speed 115200 /dev/ttyUSB0, 115200 bps C-Kermit>connect CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 ## Switch baudrate to 115200 bps and press ESC ... Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
OK, and is /tmp/kernel something with an appended dtb then?
Yes, single image suitable for single kermit UART transfer: cat arch/arm/boot/zImage arch/arm/boot/dts/armada-385-turris-omnia.dtb > /tmp/kernel
Well, OK, there we go. That's what you need to figure out how to fix booting of. You're hitting the panic in arch/arm/lib/bootm.c and need to make sure that (a) we do whatever is needed for appended dtb to be found by the kernel still/again and (b) check that ourselves, before panic or not, in that case. Before this was probably enabling ATAGs, but that wasn't (I think? I forget the magic behind appended dtb as it's been a while) actually used by Linux, just by U-Boot to not panic at that point.
Ok, thanks for hints. So seems that som unrelated code path via atags was used even for DTS booting. I also do not remember details. I will try to debug it...
Hello Tom!
I would like to know, what is required to enable same boot atags behavior like before applying that commit 9774462e34fa ("arm: Disable ATAGs support")?
I have enabled following U-Boot option (as it seems to be enough):
CONFIG_SUPPORT_PASSING_ATAGS=y
And also I have compiled kernel with following debug options:
CONFIG_DEBUG_LL=y CONFIG_DEBUG_MVEBU_UART0_ALTERNATE=y CONFIG_DEBUG_UNCOMPRESS=y
(to see early kernel output on mvebu UART console).
But I see only these lines on UART:
Starting kernel ...
DTB:0x014E0798 (0x00004F96) C:0x010000E0-0x014E5740->0x010AF400-0x01594A60 DTB:0x0158FAB8 (0x00004F96) Uncompressing Linux... done, booting the kernel.
And no more output. After some time watchdog reboots board.
Which means that something more in U-Boot is needed to enable atags booting (with possible appended DTB). Or that mentioned commit really broke booting. Any idea?
I looked at the kernel code and early code which runs prior decompresser looks if after zImage is valid magic number for DTB. And if yes, it replace content of variable where is pointer to atags struct by pointer to DTB. So if I understood it correctly then kernel completely ignores atags if there is attached DTB (after zImage). So for me it looks like U-Boot can set to r2 any value, it even does not have to be valid atags structure, kernel ignores it if it found attached DTB.

On Fri, Nov 05, 2021 at 12:38:21PM +0100, Pali Rohár wrote:
On Monday 11 October 2021 17:49:05 Pali Rohár wrote:
On Monday 11 October 2021 10:45:44 Tom Rini wrote:
On Mon, Oct 11, 2021 at 04:33:44PM +0200, Pali Rohár wrote:
On Monday 11 October 2021 10:32:22 Tom Rini wrote:
On Mon, Oct 11, 2021 at 04:25:48PM +0200, Pali Rohár wrote:
On Monday 11 October 2021 10:03:21 Tom Rini wrote: > On Mon, Oct 11, 2021 at 12:13:29PM +0200, Pali Rohár wrote: > > > Hello! > > > > Current U-Boot master has broken booting of Linux kernel over UART on > > A38x. > > > > After transferring image over UART it just prints: > > > > CACHE: Misaligned operation at range [01000000, 014e5d96] > > ## Total Size = 0x004e5d96 = 5135766 Bytes > > ## Start Addr = 0x01000000 > > Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] > > FDT and ATAGS support not compiled in > > > > resetting ... > > > > It resets board and does not boot kernel. Note that I'm trying to boot > > recent 5.15 kernel image, not something old. > > > > I did git bisect and it found following commit which broke booting: > > > > 9774462e34faaa64a91eb9c68b438a52d22bba6a is the first bad commit > > commit 9774462e34faaa64a91eb9c68b438a52d22bba6a > > Author: Tom Rini trini@konsulko.com > > Date: Mon Aug 30 09:16:30 2021 -0400 > > > > arm: Disable ATAGs support > > > > Prior this commit booting working fine. > > > > Do you have any idea what is with above commit? Or any hints? > > Can you provide the full log of what you're doing? And what's in that > image you're passing, exactly? Thanks.
Here is full log:
$ make CROSS_COMPILE=arm-linux-gnueabihf- turris_omnia_defconfig ... $ make CROSS_COMPILE=arm-linux-gnueabihf- -j8 ... $ ./tools/kwboot -b ./u-boot-spl.kwb -B 5200000 -t /dev/ttyUSB0 Patching image boot signature to UART Injecting binary header code for changing baudrate to 5200000 Bd Injecting code for changing baudrate back Aligning image header to Xmodem block size Sending boot message. Please reboot the target...- Waiting 2s and flushing tty Sending boot image header (115072 bytes)... 0 % [......................................................................] ... 93 % [........................................................... ] Done
U-Boot SPL 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200) High speed PHY - Version: 2.0 MiniPCIe/mSATA card detection... MiniPCIe Detected Device ID 6820 board SerDes lanes topology details: | Lane # | Speed | Type |
| 0 | 5 | PCIe0 | | 1 | 5 | USB3 HOST0 | | 2 | 5 | PCIe1 | | 3 | 5 | USB3 HOST1 | | 4 | 5 | PCIe2 | | 5 | 0 | SGMII2 |
High speed PHY - Ended Successfully mv_ddr: 14.0.0 DDR3 Training Sequence - Switching XBAR Window to FastPath Window mv_ddr: completed successfully Disabling MCU watchdog... disabled Trying to boot from BOOTROM Returning to BootROM (return address 0xffff05c4)...
Changing baudrate to 5200000 Bd
Sending boot image data (747780 bytes)... 0 % [......................................................................] ... 99 % [................................. ] Done Finishing transfer
Changing baudrate back to 115200 Bd
[Type Ctrl-\ + c to quit]
U-Boot 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200)
SoC: MV88F6820-A0 at 1600 MHz DRAM: 2 GiB (800 MHz, 32-bit, 2T, ECC not enabled) WDT: Started watchdog@20300 with servicing (60s timeout) MMC: mv_sdh: 0 Loading Environment from SPIFlash... SF: Detected s25fl164k with page size 256 Bytes, erase size 4 KiB, total 8 MiB OK Model: Turris Omnia Turris Omnia: RAM size: 2048 MiB Serial Number: 0000000B00007B3C Regdomain set to ** Net: eth0: ethernet@70000, eth1: ethernet@30000, eth2: ethernet@34000 =>
$ kermit C-Kermit>set line /dev/ttyUSB0 C-Kermit>set speed 115200 C-Kermit>set carrier-watch off C-Kermit>connect Connecting to /dev/ttyUSB0, speed 115200 Escape character: Ctrl-\ (ASCII 28, FS): enabled Type the escape character followed by C to get back, or followed by ? to see other options.
=> echo $uart_boot loadb $kernel_addr_r 5200000 && part uuid mmc 0:1 partuuid && setenv bootargs earlyprintk rootwait console=ttyS0,115200 rootfstype=btrfs root=PARTUUID=${partuuid} rootflags=commit=5,subvol=@ rw cfg80211.freg=${regdomain} && bootz ${kernel_addr_r} => run uart_boot ## Switch baudrate to 5200000 bps and press ENTER ... C-Kermit>set speed 5200000 ?No keywords match - 5200000 (,Transmission rate for /dev/ttyUSB0 (bits per second))
?SET SPEED fails, speed is 5260273 C-Kermit>send /tmp/kernel C-Kermit>set speed 115200 /dev/ttyUSB0, 115200 bps C-Kermit>connect CACHE: Misaligned operation at range [01000000, 014e5d96] ## Total Size = 0x004e5d96 = 5135766 Bytes ## Start Addr = 0x01000000 ## Switch baudrate to 115200 bps and press ESC ... Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] FDT and ATAGS support not compiled in
resetting ...
OK, and is /tmp/kernel something with an appended dtb then?
Yes, single image suitable for single kermit UART transfer: cat arch/arm/boot/zImage arch/arm/boot/dts/armada-385-turris-omnia.dtb > /tmp/kernel
Well, OK, there we go. That's what you need to figure out how to fix booting of. You're hitting the panic in arch/arm/lib/bootm.c and need to make sure that (a) we do whatever is needed for appended dtb to be found by the kernel still/again and (b) check that ourselves, before panic or not, in that case. Before this was probably enabling ATAGs, but that wasn't (I think? I forget the magic behind appended dtb as it's been a while) actually used by Linux, just by U-Boot to not panic at that point.
Ok, thanks for hints. So seems that som unrelated code path via atags was used even for DTS booting. I also do not remember details. I will try to debug it...
Hello Tom!
I would like to know, what is required to enable same boot atags behavior like before applying that commit 9774462e34fa ("arm: Disable ATAGs support")?
I have enabled following U-Boot option (as it seems to be enough):
CONFIG_SUPPORT_PASSING_ATAGS=y
And also I have compiled kernel with following debug options:
CONFIG_DEBUG_LL=y CONFIG_DEBUG_MVEBU_UART0_ALTERNATE=y CONFIG_DEBUG_UNCOMPRESS=y
(to see early kernel output on mvebu UART console).
But I see only these lines on UART:
Starting kernel ...
DTB:0x014E0798 (0x00004F96) C:0x010000E0-0x014E5740->0x010AF400-0x01594A60 DTB:0x0158FAB8 (0x00004F96) Uncompressing Linux... done, booting the kernel.
And no more output. After some time watchdog reboots board.
Which means that something more in U-Boot is needed to enable atags booting (with possible appended DTB). Or that mentioned commit really broke booting. Any idea?
Looking at the U-Boot commit again, you had previously also been doing CMDLINE, INITRD and MEMORY ATAGs. Since I see this in the kernel: /* * Look for an appended DTB. If found, we cannot use it to * validate the calculated start of physical memory, as its * memory nodes may need to be augmented by ATAGS stored at * an offset from the same start of physical memory. */ we might well need to still pass at least the memory tag? No one has tried (I suspect) a completely empty ATAGs + appended DTB until more or less now.

On Friday 05 November 2021 10:35:10 Tom Rini wrote:
On Fri, Nov 05, 2021 at 12:38:21PM +0100, Pali Rohár wrote:
On Monday 11 October 2021 17:49:05 Pali Rohár wrote:
On Monday 11 October 2021 10:45:44 Tom Rini wrote:
On Mon, Oct 11, 2021 at 04:33:44PM +0200, Pali Rohár wrote:
On Monday 11 October 2021 10:32:22 Tom Rini wrote:
On Mon, Oct 11, 2021 at 04:25:48PM +0200, Pali Rohár wrote: > On Monday 11 October 2021 10:03:21 Tom Rini wrote: > > On Mon, Oct 11, 2021 at 12:13:29PM +0200, Pali Rohár wrote: > > > > > Hello! > > > > > > Current U-Boot master has broken booting of Linux kernel over UART on > > > A38x. > > > > > > After transferring image over UART it just prints: > > > > > > CACHE: Misaligned operation at range [01000000, 014e5d96] > > > ## Total Size = 0x004e5d96 = 5135766 Bytes > > > ## Start Addr = 0x01000000 > > > Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] > > > FDT and ATAGS support not compiled in > > > > > > resetting ... > > > > > > It resets board and does not boot kernel. Note that I'm trying to boot > > > recent 5.15 kernel image, not something old. > > > > > > I did git bisect and it found following commit which broke booting: > > > > > > 9774462e34faaa64a91eb9c68b438a52d22bba6a is the first bad commit > > > commit 9774462e34faaa64a91eb9c68b438a52d22bba6a > > > Author: Tom Rini trini@konsulko.com > > > Date: Mon Aug 30 09:16:30 2021 -0400 > > > > > > arm: Disable ATAGs support > > > > > > Prior this commit booting working fine. > > > > > > Do you have any idea what is with above commit? Or any hints? > > > > Can you provide the full log of what you're doing? And what's in that > > image you're passing, exactly? Thanks. > > Here is full log: > > $ make CROSS_COMPILE=arm-linux-gnueabihf- turris_omnia_defconfig > ... > $ make CROSS_COMPILE=arm-linux-gnueabihf- -j8 > ... > $ ./tools/kwboot -b ./u-boot-spl.kwb -B 5200000 -t /dev/ttyUSB0 > Patching image boot signature to UART > Injecting binary header code for changing baudrate to 5200000 Bd > Injecting code for changing baudrate back > Aligning image header to Xmodem block size > Sending boot message. Please reboot the target...- > Waiting 2s and flushing tty > Sending boot image header (115072 bytes)... > 0 % [......................................................................] > ... > 93 % [........................................................... ] > Done > > U-Boot SPL 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200) > High speed PHY - Version: 2.0 > MiniPCIe/mSATA card detection... MiniPCIe > Detected Device ID 6820 > board SerDes lanes topology details: > | Lane # | Speed | Type | > -------------------------------- > | 0 | 5 | PCIe0 | > | 1 | 5 | USB3 HOST0 | > | 2 | 5 | PCIe1 | > | 3 | 5 | USB3 HOST1 | > | 4 | 5 | PCIe2 | > | 5 | 0 | SGMII2 | > -------------------------------- > High speed PHY - Ended Successfully > mv_ddr: 14.0.0 > DDR3 Training Sequence - Switching XBAR Window to FastPath Window > mv_ddr: completed successfully > Disabling MCU watchdog... disabled > Trying to boot from BOOTROM > Returning to BootROM (return address 0xffff05c4)... > > Changing baudrate to 5200000 Bd > > Sending boot image data (747780 bytes)... > 0 % [......................................................................] > ... > 99 % [................................. ] > Done > Finishing transfer > > Changing baudrate back to 115200 Bd > > [Type Ctrl-\ + c to quit] > > > U-Boot 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200) > > SoC: MV88F6820-A0 at 1600 MHz > DRAM: 2 GiB (800 MHz, 32-bit, 2T, ECC not enabled) > WDT: Started watchdog@20300 with servicing (60s timeout) > MMC: mv_sdh: 0 > Loading Environment from SPIFlash... SF: Detected s25fl164k with page size 256 Bytes, erase size 4 KiB, total 8 MiB > OK > Model: Turris Omnia > Turris Omnia: > RAM size: 2048 MiB > Serial Number: 0000000B00007B3C > Regdomain set to ** > Net: eth0: ethernet@70000, eth1: ethernet@30000, eth2: ethernet@34000 > => > > $ kermit > C-Kermit>set line /dev/ttyUSB0 > C-Kermit>set speed 115200 > C-Kermit>set carrier-watch off > C-Kermit>connect > Connecting to /dev/ttyUSB0, speed 115200 > Escape character: Ctrl-\ (ASCII 28, FS): enabled > Type the escape character followed by C to get back, > or followed by ? to see other options. > ---------------------------------------------------- > > => echo $uart_boot > loadb $kernel_addr_r 5200000 && part uuid mmc 0:1 partuuid && setenv bootargs earlyprintk rootwait console=ttyS0,115200 rootfstype=btrfs root=PARTUUID=${partuuid} rootflags=commit=5,subvol=@ rw cfg80211.freg=${regdomain} && bootz ${kernel_addr_r} > => run uart_boot > ## Switch baudrate to 5200000 bps and press ENTER ... > C-Kermit>set speed 5200000 > ?No keywords match - 5200000 (,Transmission rate for /dev/ttyUSB0 (bits per second)) > > ?SET SPEED fails, speed is 5260273 > C-Kermit>send /tmp/kernel > C-Kermit>set speed 115200 > /dev/ttyUSB0, 115200 bps > C-Kermit>connect > CACHE: Misaligned operation at range [01000000, 014e5d96] > ## Total Size = 0x004e5d96 = 5135766 Bytes > ## Start Addr = 0x01000000 > ## Switch baudrate to 115200 bps and press ESC ... > Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] > FDT and ATAGS support not compiled in > > resetting ...
OK, and is /tmp/kernel something with an appended dtb then?
Yes, single image suitable for single kermit UART transfer: cat arch/arm/boot/zImage arch/arm/boot/dts/armada-385-turris-omnia.dtb > /tmp/kernel
Well, OK, there we go. That's what you need to figure out how to fix booting of. You're hitting the panic in arch/arm/lib/bootm.c and need to make sure that (a) we do whatever is needed for appended dtb to be found by the kernel still/again and (b) check that ourselves, before panic or not, in that case. Before this was probably enabling ATAGs, but that wasn't (I think? I forget the magic behind appended dtb as it's been a while) actually used by Linux, just by U-Boot to not panic at that point.
Ok, thanks for hints. So seems that som unrelated code path via atags was used even for DTS booting. I also do not remember details. I will try to debug it...
Hello Tom!
I would like to know, what is required to enable same boot atags behavior like before applying that commit 9774462e34fa ("arm: Disable ATAGs support")?
I have enabled following U-Boot option (as it seems to be enough):
CONFIG_SUPPORT_PASSING_ATAGS=y
And also I have compiled kernel with following debug options:
CONFIG_DEBUG_LL=y CONFIG_DEBUG_MVEBU_UART0_ALTERNATE=y CONFIG_DEBUG_UNCOMPRESS=y
(to see early kernel output on mvebu UART console).
But I see only these lines on UART:
Starting kernel ...
DTB:0x014E0798 (0x00004F96) C:0x010000E0-0x014E5740->0x010AF400-0x01594A60 DTB:0x0158FAB8 (0x00004F96) Uncompressing Linux... done, booting the kernel.
And no more output. After some time watchdog reboots board.
Which means that something more in U-Boot is needed to enable atags booting (with possible appended DTB). Or that mentioned commit really broke booting. Any idea?
Looking at the U-Boot commit again, you had previously also been doing CMDLINE, INITRD and MEMORY ATAGs. Since I see this in the kernel: /* * Look for an appended DTB. If found, we cannot use it to * validate the calculated start of physical memory, as its * memory nodes may need to be augmented by ATAGS stored at * an offset from the same start of physical memory. */ we might well need to still pass at least the memory tag? No one has tried (I suspect) a completely empty ATAGs + appended DTB until more or less now.
Now I found it! Issue is with CMDLINE. Without CONFIG_CMDLINE_TAG kernel does not see any cmdline passed by bootloader, it fallbacks to default cmdline (which was empty for my zImage) and therefore has not printed anything on UART (because console=... was not there). Missing rootfs then caused freeze, timeout and board reset. So it looked like U-Boot was not able to boot kernel at all, even everything worked fine. I realized it with CONFIG_CMDLINE="earlyprintk console=ttyS0,115200" kernel config option.
Compiling U-Boot with CONFIG_CMDLINE_TAG=y fixed this issue as U-Boot started passing cmdline to kernel again.
So now I have a question: Do we want to support booting zImage with appended DTB in U-Boot when ATAGs support is now disabled by default?

On Fri, Nov 05, 2021 at 04:16:46PM +0100, Pali Rohár wrote:
On Friday 05 November 2021 10:35:10 Tom Rini wrote:
On Fri, Nov 05, 2021 at 12:38:21PM +0100, Pali Rohár wrote:
On Monday 11 October 2021 17:49:05 Pali Rohár wrote:
On Monday 11 October 2021 10:45:44 Tom Rini wrote:
On Mon, Oct 11, 2021 at 04:33:44PM +0200, Pali Rohár wrote:
On Monday 11 October 2021 10:32:22 Tom Rini wrote: > On Mon, Oct 11, 2021 at 04:25:48PM +0200, Pali Rohár wrote: > > On Monday 11 October 2021 10:03:21 Tom Rini wrote: > > > On Mon, Oct 11, 2021 at 12:13:29PM +0200, Pali Rohár wrote: > > > > > > > Hello! > > > > > > > > Current U-Boot master has broken booting of Linux kernel over UART on > > > > A38x. > > > > > > > > After transferring image over UART it just prints: > > > > > > > > CACHE: Misaligned operation at range [01000000, 014e5d96] > > > > ## Total Size = 0x004e5d96 = 5135766 Bytes > > > > ## Start Addr = 0x01000000 > > > > Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] > > > > FDT and ATAGS support not compiled in > > > > > > > > resetting ... > > > > > > > > It resets board and does not boot kernel. Note that I'm trying to boot > > > > recent 5.15 kernel image, not something old. > > > > > > > > I did git bisect and it found following commit which broke booting: > > > > > > > > 9774462e34faaa64a91eb9c68b438a52d22bba6a is the first bad commit > > > > commit 9774462e34faaa64a91eb9c68b438a52d22bba6a > > > > Author: Tom Rini trini@konsulko.com > > > > Date: Mon Aug 30 09:16:30 2021 -0400 > > > > > > > > arm: Disable ATAGs support > > > > > > > > Prior this commit booting working fine. > > > > > > > > Do you have any idea what is with above commit? Or any hints? > > > > > > Can you provide the full log of what you're doing? And what's in that > > > image you're passing, exactly? Thanks. > > > > Here is full log: > > > > $ make CROSS_COMPILE=arm-linux-gnueabihf- turris_omnia_defconfig > > ... > > $ make CROSS_COMPILE=arm-linux-gnueabihf- -j8 > > ... > > $ ./tools/kwboot -b ./u-boot-spl.kwb -B 5200000 -t /dev/ttyUSB0 > > Patching image boot signature to UART > > Injecting binary header code for changing baudrate to 5200000 Bd > > Injecting code for changing baudrate back > > Aligning image header to Xmodem block size > > Sending boot message. Please reboot the target...- > > Waiting 2s and flushing tty > > Sending boot image header (115072 bytes)... > > 0 % [......................................................................] > > ... > > 93 % [........................................................... ] > > Done > > > > U-Boot SPL 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200) > > High speed PHY - Version: 2.0 > > MiniPCIe/mSATA card detection... MiniPCIe > > Detected Device ID 6820 > > board SerDes lanes topology details: > > | Lane # | Speed | Type | > > -------------------------------- > > | 0 | 5 | PCIe0 | > > | 1 | 5 | USB3 HOST0 | > > | 2 | 5 | PCIe1 | > > | 3 | 5 | USB3 HOST1 | > > | 4 | 5 | PCIe2 | > > | 5 | 0 | SGMII2 | > > -------------------------------- > > High speed PHY - Ended Successfully > > mv_ddr: 14.0.0 > > DDR3 Training Sequence - Switching XBAR Window to FastPath Window > > mv_ddr: completed successfully > > Disabling MCU watchdog... disabled > > Trying to boot from BOOTROM > > Returning to BootROM (return address 0xffff05c4)... > > > > Changing baudrate to 5200000 Bd > > > > Sending boot image data (747780 bytes)... > > 0 % [......................................................................] > > ... > > 99 % [................................. ] > > Done > > Finishing transfer > > > > Changing baudrate back to 115200 Bd > > > > [Type Ctrl-\ + c to quit] > > > > > > U-Boot 2021.10-00600-gf331497d3ad4 (Oct 11 2021 - 16:13:39 +0200) > > > > SoC: MV88F6820-A0 at 1600 MHz > > DRAM: 2 GiB (800 MHz, 32-bit, 2T, ECC not enabled) > > WDT: Started watchdog@20300 with servicing (60s timeout) > > MMC: mv_sdh: 0 > > Loading Environment from SPIFlash... SF: Detected s25fl164k with page size 256 Bytes, erase size 4 KiB, total 8 MiB > > OK > > Model: Turris Omnia > > Turris Omnia: > > RAM size: 2048 MiB > > Serial Number: 0000000B00007B3C > > Regdomain set to ** > > Net: eth0: ethernet@70000, eth1: ethernet@30000, eth2: ethernet@34000 > > => > > > > $ kermit > > C-Kermit>set line /dev/ttyUSB0 > > C-Kermit>set speed 115200 > > C-Kermit>set carrier-watch off > > C-Kermit>connect > > Connecting to /dev/ttyUSB0, speed 115200 > > Escape character: Ctrl-\ (ASCII 28, FS): enabled > > Type the escape character followed by C to get back, > > or followed by ? to see other options. > > ---------------------------------------------------- > > > > => echo $uart_boot > > loadb $kernel_addr_r 5200000 && part uuid mmc 0:1 partuuid && setenv bootargs earlyprintk rootwait console=ttyS0,115200 rootfstype=btrfs root=PARTUUID=${partuuid} rootflags=commit=5,subvol=@ rw cfg80211.freg=${regdomain} && bootz ${kernel_addr_r} > > => run uart_boot > > ## Switch baudrate to 5200000 bps and press ENTER ... > > C-Kermit>set speed 5200000 > > ?No keywords match - 5200000 (,Transmission rate for /dev/ttyUSB0 (bits per second)) > > > > ?SET SPEED fails, speed is 5260273 > > C-Kermit>send /tmp/kernel > > C-Kermit>set speed 115200 > > /dev/ttyUSB0, 115200 bps > > C-Kermit>connect > > CACHE: Misaligned operation at range [01000000, 014e5d96] > > ## Total Size = 0x004e5d96 = 5135766 Bytes > > ## Start Addr = 0x01000000 > > ## Switch baudrate to 115200 bps and press ESC ... > > Kernel image @ 0x1000000 [ 0x000000 - 0x4e0e60 ] > > FDT and ATAGS support not compiled in > > > > resetting ... > > OK, and is /tmp/kernel something with an appended dtb then?
Yes, single image suitable for single kermit UART transfer: cat arch/arm/boot/zImage arch/arm/boot/dts/armada-385-turris-omnia.dtb > /tmp/kernel
Well, OK, there we go. That's what you need to figure out how to fix booting of. You're hitting the panic in arch/arm/lib/bootm.c and need to make sure that (a) we do whatever is needed for appended dtb to be found by the kernel still/again and (b) check that ourselves, before panic or not, in that case. Before this was probably enabling ATAGs, but that wasn't (I think? I forget the magic behind appended dtb as it's been a while) actually used by Linux, just by U-Boot to not panic at that point.
Ok, thanks for hints. So seems that som unrelated code path via atags was used even for DTS booting. I also do not remember details. I will try to debug it...
Hello Tom!
I would like to know, what is required to enable same boot atags behavior like before applying that commit 9774462e34fa ("arm: Disable ATAGs support")?
I have enabled following U-Boot option (as it seems to be enough):
CONFIG_SUPPORT_PASSING_ATAGS=y
And also I have compiled kernel with following debug options:
CONFIG_DEBUG_LL=y CONFIG_DEBUG_MVEBU_UART0_ALTERNATE=y CONFIG_DEBUG_UNCOMPRESS=y
(to see early kernel output on mvebu UART console).
But I see only these lines on UART:
Starting kernel ...
DTB:0x014E0798 (0x00004F96) C:0x010000E0-0x014E5740->0x010AF400-0x01594A60 DTB:0x0158FAB8 (0x00004F96) Uncompressing Linux... done, booting the kernel.
And no more output. After some time watchdog reboots board.
Which means that something more in U-Boot is needed to enable atags booting (with possible appended DTB). Or that mentioned commit really broke booting. Any idea?
Looking at the U-Boot commit again, you had previously also been doing CMDLINE, INITRD and MEMORY ATAGs. Since I see this in the kernel: /* * Look for an appended DTB. If found, we cannot use it to * validate the calculated start of physical memory, as its * memory nodes may need to be augmented by ATAGS stored at * an offset from the same start of physical memory. */ we might well need to still pass at least the memory tag? No one has tried (I suspect) a completely empty ATAGs + appended DTB until more or less now.
Now I found it! Issue is with CMDLINE. Without CONFIG_CMDLINE_TAG kernel does not see any cmdline passed by bootloader, it fallbacks to default cmdline (which was empty for my zImage) and therefore has not printed anything on UART (because console=... was not there). Missing rootfs then caused freeze, timeout and board reset. So it looked like U-Boot was not able to boot kernel at all, even everything worked fine. I realized it with CONFIG_CMDLINE="earlyprintk console=ttyS0,115200" kernel config option.
Compiling U-Boot with CONFIG_CMDLINE_TAG=y fixed this issue as U-Boot started passing cmdline to kernel again.
So now I have a question: Do we want to support booting zImage with appended DTB in U-Boot when ATAGs support is now disabled by default?
Based on your experience, yes, there are use cases for appended dtb booting still. So it should be at least documented what you need to do where in order for that to work, and perhaps some platforms will want to enable it by default.

On Friday 05 November 2021 11:20:01 Tom Rini wrote:
On Fri, Nov 05, 2021 at 04:16:46PM +0100, Pali Rohár wrote:
So now I have a question: Do we want to support booting zImage with appended DTB in U-Boot when ATAGs support is now disabled by default?
Based on your experience, yes, there are use cases for appended dtb booting still. So it should be at least documented what you need to do where in order for that to work, and perhaps some platforms will want to enable it by default.
What could be implemented in U-Boot is extracting DTB from zImage+DTB binary and boot it like if user supply separate zImage and separate DTB files. With this approach there is no need to have ATAGs support enabled. It would mean that kernel's code for using attached DTB would not be used anymore as DTB would be passed to kernel separately, like any modern boot setup.
Main issue with this approach is that if you load zImage+DTB binary from disk or UART into memory then you loose information about total binary size. And if you examine memory after the zImage, you cannot be sure if data were loaded by previous command (disk read, UART transfer) or if is just some garbage in RAM. So you can have false-positive detection that DTB was appended.
This issue does not happen in case of booting zImage+DTB encapsulated in uImage format, as in uImage is stored total size of that concatenated binary. So booting via bootm should be fine. IIRC zImage+DTB-in-uImage via bootm is used for booting new kernels on Nokia N900.
Currently affected by this issue is bootz command, which takes only start address of the zImage binary and total size is not specified. Command bootz takes third argument which specifies location of DTB in memory and understand special value "-" which says to atags booting. I'm thinking here... what about adding a new special value e.g. "+" which would mean that DTB is attached to zImage? This could issue that automatic detection of attached DTB into zImage is not reliable.
Any opinion?
Another approach instead of extracting DTB from zImage+DTB binary could be to teach U-Boot to provide some simple minimalistic ATAGs and then boot those zImage+DTB binaries like before with minimalistic ATAGs...

On Fri, Nov 05, 2021 at 04:47:31PM +0100, Pali Rohár wrote:
On Friday 05 November 2021 11:20:01 Tom Rini wrote:
On Fri, Nov 05, 2021 at 04:16:46PM +0100, Pali Rohár wrote:
So now I have a question: Do we want to support booting zImage with appended DTB in U-Boot when ATAGs support is now disabled by default?
Based on your experience, yes, there are use cases for appended dtb booting still. So it should be at least documented what you need to do where in order for that to work, and perhaps some platforms will want to enable it by default.
What could be implemented in U-Boot is extracting DTB from zImage+DTB binary and boot it like if user supply separate zImage and separate DTB files. With this approach there is no need to have ATAGs support enabled. It would mean that kernel's code for using attached DTB would not be used anymore as DTB would be passed to kernel separately, like any modern boot setup.
Main issue with this approach is that if you load zImage+DTB binary from disk or UART into memory then you loose information about total binary size. And if you examine memory after the zImage, you cannot be sure if data were loaded by previous command (disk read, UART transfer) or if is just some garbage in RAM. So you can have false-positive detection that DTB was appended.
This issue does not happen in case of booting zImage+DTB encapsulated in uImage format, as in uImage is stored total size of that concatenated binary. So booting via bootm should be fine. IIRC zImage+DTB-in-uImage via bootm is used for booting new kernels on Nokia N900.
Currently affected by this issue is bootz command, which takes only start address of the zImage binary and total size is not specified. Command bootz takes third argument which specifies location of DTB in memory and understand special value "-" which says to atags booting. I'm thinking here... what about adding a new special value e.g. "+" which would mean that DTB is attached to zImage? This could issue that automatic detection of attached DTB into zImage is not reliable.
Any opinion?
Another approach instead of extracting DTB from zImage+DTB binary could be to teach U-Boot to provide some simple minimalistic ATAGs and then boot those zImage+DTB binaries like before with minimalistic ATAGs...
So, there's certainly still valid reasons and times to boot an appended DTB. It's just not a generally common case I think. But it does show that ATAGs were getting a bit more use still than I had expected. I think we should update the help / prompt on SUPPORT_PASSING_ATAGS to make it clear this is needed for appended dtb booting and if I followed you right, CMDLINE should at least also be enabled for that case, and maybe also update something under doc/. I don't think we should put too much effort in to making us find and pass the appended dtb for what is an otherwise niche case.
participants (2)
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Pali Rohár
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Tom Rini