A38x: Broken Linux kernel booting over UART

[Pali Rohár]

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 at 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 at 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 at 70000, eth1: ethernet at 30000, eth2: ethernet at 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 ...