[Letux-kernel] X1600 / LX16 support - here: adding MMC

[H. Nikolaus Schaller]

> Am 09.02.2024 um 22:27 schrieb Andreas Kemnade <andreas at kemnade.info>:
> 
> On Fri, 9 Feb 2024 21:53:04 +0100
> Andreas Kemnade <andreas at kemnade.info> wrote:
> 
>> On Fri, 9 Feb 2024 18:10:49 +0100
>> "H. Nikolaus Schaller" <hns at goldelico.com> wrote:
>> 
>>>> I have debugged several other emmc/sd problems on other boards this way.    
>>> 
>>> I agree that it can work but IMHO setting it up is quite a distraction
>>> and in the saved time the problem can be analysed by different methods.
>>> 
>>> But we can of course work in parallel - and one method will find the bugs.
>>> 
>> something interesting seen:
>> while typing in commands in the shell.
>> 
>> ke[    0.000191] mmc0: host does not support reading read-only switch, assuming 
>> write-enable
>> [    0.000191] mmc0: new high speed SDHC card at address 59b4
>> [    0.000191] mmcblk0: mmc0:59b4 SN32G 29.7 GiB
>> [    0.000191]  mmcblk0: unable to read partition table
>> [    0.000191] mmc0: card 59b4 removed
>> r[    0.000191] mmc0: host does not support reading read-only switch, assuming write-enable
>> [    0.000191] mmc0: error -145 whilst initialising SD card
>> 
>> and endless errors again...
>> 
> but only for mmc1.
> 
> tried again with setting bus-width to 1 and I got immediately:
> [    0.000192] jz4740-mmc 13460000.mmc: Ingenic SD/MMC card driver registered
> [    0.000192] jz4740-mmc 13460000.mmc: Using DMA, 4-bit mode
> [    0.000192] Freeing unused kernel image (initmem) memory: 1316K
> [    0.000192] This architecture does not have kernel memory protection.
> [    0.000192] Run /sbin/init as init process
> [    0.000192]   with arguments:
> [    0.000192]     /sbin/init
> [    0.000192]   with environment:
> [    0.000192]     HOME=/
> [    0.000192]     TERM=linux
> [    0.000192] process '/bin/busybox' started with executable stack
> ^Mcan't run '/etc/init.d/rcS': No such file or directory
> 
> Please press Enter to activa[    0.000192] jz4740-mmc 13460000.mmc: no support for card's volts
> te this console. [    0.000192] mmc1: error -22 whilst initialising SDIO card
> [    0.000192] mmc0: host does not support reading read-only switch, assuming write-enable
> [    0.000192] mmc0: new high speed SDHC card at address 59b4
> [    0.000192] mmcblk0: mmc0:59b4 SN32G 29.7 GiB

That is good!

> [    0.000192]  mmcblk0: unable to read partition table
> [    0.000192] mmc0: card 59b4 removed
> 
> and silence besides of mmc1 errors.

What I have as a theory is that the clocks are wrong and outside of specs. Some SD card
and some x1600 MSC may handle this well - and in some cases not.

BR,
Nikolaus