[Letux-kernel] [PATCH 00/20] A bunch of JZ4730 fixups for letux-kernel

[H. Nikolaus Schaller]

> Am 28.11.2020 um 11:45 schrieb H. Nikolaus Schaller <hns at goldelico.com>:
> 
> Hi Lubomir,
> 
>> Am 27.11.2020 um 22:52 schrieb Lubomir Rintel <lkundrak at v3.sk>:
>> 
>> On Fri, Nov 27, 2020 at 01:45:43PM +0100, H. Nikolaus Schaller wrote:
>>> 
>>> Maybe can you send me your uImage binary for comparison and trying to boot that one?
>> 
>> Yes. Here's a branch [1] you've requested elsewhere in this thread, with
>> the last commit containing the build script and a built uImage:
>> 
>> git pull git://git.kernel.org/pub/scm/linux/kernel/git/lkundrak/linux.git lr/alpha400-for-nicholas
>> 
>> [1] https://git.kernel.org/pub/scm/linux/kernel/git/lkundrak/linux.git/log/?h=lr/alpha400-for-nicholas
> 
> Great! Your uImage boots.
> 
> So I can now try to find out what is different with my build process. Maybe some compiler option...

iMac:master hns$ file uImage arch/mips/boot/uImage
uImage:                u-boot legacy uImage, , Linux/MIPS, OS Kernel Image (gzip), 2849048 bytes, Fri Nov 27 18:51:04 2020, Load Address: 0x80100000, Entry Point: 0x80523BE8, Header CRC: 0xB17ACF55, Data CRC: 0x3BDC1AC6
arch/mips/boot/uImage: u-boot legacy uImage, , Linux/MIPS, OS Kernel Image (gzip), 5218723 bytes, Sat Nov 28 12:14:54 2020, Load Address: 0x80100000, Entry Point: 0x80523BE8, Header CRC: 0x5F4E2857, Data CRC: 0xBCF47A89
iMac:master hns$ 

Only the file size differs! Even the entry point is the same.

After finding a bug in my mkimage generator (it did not take the newly built vmlinux in a subdirectory but an old version in the root of my source tree) the results became better, but still no improvement.

Then I checked out your complete tree, copied the .config to the right location and:

2919423 bytes read
## Booting image at 80600000 ...
   Image Name:   Linux-5.10.0-rc5-letux-l400+
   Image Type:   MIPS Linux Kernel Image (gzip compressed)
   Data Size:    2919359 Bytes =  2.8 MB
   Load Address: 80100000
   Entry Point:  8053d0f4
   Verifying Checksum ... OK
   Uncompressing Kernel Image ... OK

Starting kernel ...

[    0.000000] Linux version 5.10.0-rc5-letux-l400+ (hns at iMac.fritz.box) (mipsel-linux-gnu-gcc (GCC) 4.9.2, GNU ld (GNU Binutils) 2.25) #4026 PREEMPT Sat Nov 28 14:32:55 CET 2020
[    0.000000] CPU0 revision is: 02d0024f (Ingenic XBurst)
[    0.000000] MIPS: machine is letux400,minipc
[    0.000000] earlycon: jz4740_uart0 at MMIO32 0x10030000 (options '115200n8')
[    0.000000] printk: bootconsole [jz4740_uart0] enabled
[    0.000000] printk: debug: ignoring loglevel setting.
[    0.000000] User-defined physical RAM map overwrite
[    0.000000] Initrd not found or empty - disabling initrd
[    0.000000] cma: Reserved 32 MiB at 0x01000000
...

So there is a subtle difference between your minimalistic tree and the full letux tree which blows up the uImage by ca. 80% and makes it fail to boot.
Have to study this now... But I think we are close.

BR and thanks,
Nikolaus