[Letux-kernel] jz4730-i2c - clocksource

[H. Nikolaus Schaller]

Hi Paul,

> Am 07.03.2021 um 14:05 schrieb Paul Boddie <paul at boddie.org.uk>:
> 
> On Sunday, 7 March 2021 00:16:53 CET Paul Boddie wrote:
>> On Saturday, 6 March 2021 23:20:48 CET H. Nikolaus Schaller wrote:
>>> You might try to download my binary builds and replace uImage or modules
>>> or DTB to check where the difference is.
>>> 
>>> https://download.goldelico.com/letux-kernel/latest-l400/
>>> 
>>> And, which defconfig did you use? I use the letix_mipsbook_defconfig.
>>> The alpha400_defconfig may be incomplete for LCD.
>> 
>> I'll try again with letux_mipsbook_defconfig and see if it makes a
>> difference.
> 
> Since I suspect that I am making a mistake in deploying the files, where 
> should each of these things go on a memory card?
> 
> The uImage file should go in the first (FAT) partition, of course.

Yes. Exact names depends on what U-Boot expects. On my system it should be
named "Image" without the "u".

> 
> The second partition should contain the root filesystem. I found that unlike 
> the legacy configuration, which used ext2, the kernel command line only had 
> ext4 and ext3 for the rootfstype. So I changed the command line and stuck with 
> the ext2 format for now.

AFAIR you can read ext2 through ext3 driver. But of course you are free to change
that. Kernel would warn/fail if the config doesn't match the SD card.

> 
> The modules are presumably installed to the second partition as normal, this 
> typically being done using the modules_install Makefile target with 
> INSTALL_MOD_PATH set to the base of the mounted partition. They should end up 
> at the following location within INSTALL_MOD_PATH:
> 
> lib/modules/5.12.0-rc2-letux-l400+

Yes. They go to /lib/modules/5.12.0-rc2-letux-l400+/

> 
> The device tree files are typically installed using the dtbs_install Makefile 
> target with INSTALL_PATH set to the location of the boot directory. They 
> should end up at the following location within INSTALL_PATH:
> 
> dtbs/5.12.0-rc2-letux-l400+/ingenic/alpha400.dtb
> 
> Normally, this would be the following in the running system:
> 
> /boot/dtbs/5.12.0-rc2-letux-l400+/ingenic/alpha400.dtb
> 
> This is where I wonder if I am doing something wrong because the device-
> trees.tbz download has one file with this path:
> 
> ingenic/alpha400.dtb
> 
> Where would this be unpacked? Should it be on the first partition? What 
> happened to the dtbs/5.12.0-rc2-letux-l400+ part of the path?

It should go to /boot and dtbs/5.12.0-rc2-letux-l400+ should be stripped
off. The reason is that this is loaded by U-Boot which does not know the
exact kernel name. Only the kernel knows its name and can search modules
in /lib/modules/5.12.0-rc2-letux-l400+/

This means the .dtb must be located where U-Boot (or a boot.scr) is looking
for it.

So I have:

root at letux:~# ls -lR /boot
/boot:
total 5136
-rw-r--r-- 1 root root 5232705 Mar  4  2021 Image
-rw-r--r-- 1 root root      96 Mar  4  2021 Image.info
-rw-r--r-- 1 root root    2108 Mar  4  2021 bootargs.scr
drwxr-xr-x 2 root root    4096 Mar  4  2021 ingenic

/boot/ingenic:
total 12
-rw-r--r-- 1 root root 12078 Mar  3  2021 alpha400.dtb
root at letux:~# ls -l /lib/modules/5.12.0-rc2-letux-l400+/
total 696
drwxr-xr-x 8 1002 root   4096 Mar  7  2021 kernel
-rw-r--r-- 1 root root 107540 Jan  1 00:01 modules.alias
-rw-r--r-- 1 root root 114082 Jan  1 00:01 modules.alias.bin
-rw-r--r-- 1 1002 root  13845 Mar  7  2021 modules.builtin
-rw-r--r-- 1 root root  15600 Jan  1 00:01 modules.builtin.bin
-rw-r--r-- 1 1002 root  69374 Mar  7  2021 modules.builtin.modinfo
-rw-r--r-- 1 1002 root     69 Mar  7  2021 modules.ccwmap
-rw-r--r-- 1 root root  23159 Jan  1 00:01 modules.dep
-rw-r--r-- 1 root root  40380 Jan  1 00:01 modules.dep.bin
-rw-r--r-- 1 root root    134 Jan  1 00:01 modules.devname
-rw-r--r-- 1 1002 root     73 Mar  7  2021 modules.ieee1394map
-rw-r--r-- 1 1002 root    141 Mar  7  2021 modules.inputmap
-rw-r--r-- 1 1002 root     81 Mar  7  2021 modules.isapnpmap
-rw-r--r-- 1 1002 root     74 Mar  7  2021 modules.ofmap
-rw-r--r-- 1 1002 root  14338 Mar  7  2021 modules.order
-rw-r--r-- 1 1002 root     99 Mar  7  2021 modules.pcimap
-rw-r--r-- 1 1002 root     43 Mar  7  2021 modules.seriomap
-rw-r--r-- 1 root root     55 Jan  1 00:01 modules.softdep
-rw-r--r-- 1 root root 105905 Jan  1 00:01 modules.symbols
-rw-r--r-- 1 root root 127270 Jan  1 00:01 modules.symbols.bin
-rw-r--r-- 1 1002 root    189 Mar  7  2021 modules.usbmap
root at letux:~# 

Hope this helps!

BR,
Nikolaus


PS: I think one of my fixes for the ingenic-timer for jz4730
did break the jz4770-tcu code which is used by the jz4780.
Have a fix almost tested.

BTW: the jz4780 does NOT use the ingenic-ost timers. It completely
relies on the 16 bit jz4770-ingenic-timer.

PPS: the jz4780.dtsi also defines the timers as "interrupt-controller"
which is IMHO nonsense. It would allow

	interrupt-parent = <&tcu>;

This may also affect initialization of the ingenic-timer.
But if I remove it we get:

[ 0.000000] clocksource: ingenic-timer: mask: 0xffff max_cycles: 0xffff, max_idle_ns: 38884100 ns
[ 0.000000] ingenic_tcu_init: Unable to start CPU timers: -19
[ 0.000000] Failed to initialize '/timer at 10002000': -19
[ 0.000000] timer_probe: no matching timers found