Hi, with the latest letux-4.16 kernel it is again possible to flash some Letux-OS into the eMMC. Intermediate versions had an experimental driver which is broken, so that the eMMC was usually inaccessible from user-space.
The new kernel tree includes a tool /root/tsx [1] which allows to manually controls the txs02612 to switch between µSD and eMMC.
It is simple to use:
/root/txs eMMC switches to eMMC /root/txs uSD switches to µSD
It calls partprobe so that the partitions become available.
Now we can use makesd [2] to install some Letux-OS variant in eMMC:
1. download makesd as described on the project page [2] to your host PC 2. make an SD card for the Pyra: DEV=/dev/your-sd-reader pyra -r xfce or use pyra-4g for 4GB RAM 3. copy makesd to the rootfs partition (so that we can run it on the Pyra as well) 4. boot the Pyra with this 4.16 based SD card 5. console login or ssh into the Pyra 6. setup outgoing internet connection on the Pyra (e.g. through ethernet-gadget over USB) 7. /root/txs eMMC 8. check by cat /proc/partitions that the eMMC has been selected as /dev/mmcblk0 you see that the special boot sectors mmcblk0boot0 exist 9. DEV=/dev/mmcblk0 ./makesd pyra -r xfce or use pyra-4g for 4GB RAM
Note that this flashes Letux-OS (with a not well configured XFCE) and not Pyra-OS. But it should be possible to copy/reuse some principles and code for a Pyra-OS flasher.
In the long run, we should get rid of the /root/txs tool.
This needs someone to write a better driver [3] that hooks itself into the MMC subsystem of Linux and automatically controls the switch. Then, the eMMC will always be accessible and an µSD in addition/parallel if installed.
But this driver does not yet exist. Besides a failed experimental one [4] which tried to use the SDIO subdevice mechanism.
A better driver might follow the principles of the i2c-mux drivers: drivers/i2c/i2c-mux.c. But that is up to the developer of a better driver to decide how it is to be done.
BR, Nikolaus
[1]: http://git.goldelico.com/?p=gta04-kernel.git;a=commit;h=a00abbbf2d67bd5c0548... [2]: http://projects.goldelico.com/p/gta04-makesd/ [3]: http://projects.goldelico.com/p/gta04-kernel/issues/698/ [4]: http://git.goldelico.com/?p=gta04-kernel.git;a=shortlog;h=refs/heads/work/le...
On 04/13/2018 07:54 PM, H. Nikolaus Schaller wrote:
Hi, with the latest letux-4.16 kernel it is again possible to flash some Letux-OS into the eMMC. Intermediate versions had an experimental driver which is broken, so that the eMMC was usually inaccessible from user-space.
The new kernel tree includes a tool /root/tsx [1] which allows to manually controls the txs02612 to switch between µSD and eMMC.
How are the defaults set up ? I'd prefer it to have the eMMC as default, and have uboot/linux switch to µSD if it detects a card at boot.
Hi,
Am 14.04.2018 um 09:30 schrieb aTc atc@k-n-p.org:
On 04/13/2018 07:54 PM, H. Nikolaus Schaller wrote:
Hi, with the latest letux-4.16 kernel it is again possible to flash some Letux-OS into the eMMC. Intermediate versions had an experimental driver which is broken, so that the eMMC was usually inaccessible from user-space. The new kernel tree includes a tool /root/tsx [1] which allows to manually controls the txs02612 to switch between µSD and eMMC.
How are the defaults set up ?
Well, this depends on how they are defined in u-boot and kernel code... They can either be defined to set or clear the control gpio, which chooses between µSG and eMMC.
There is also a hardware override to be able to force load of SPL/MLO from either one, but this becomes disabled as soon as MLO is started.
I'd prefer it to have the eMMC as default, and have uboot/linux switch to µSD if it detects a card at boot.
Yes, I'd like to have it the same way.
And it is already (almost) this way in current u-boot and kernel code.
Except for auto-detection of µSD. This needs special drivers for U-Boot and Kernel I did mention. May even be simpler in Kernel than in U-Boot (because µSD detection is not easily scriptable).
In other words, if you follow the instructions, you can then boot completely from eMMC (but not yet from µSD). You can always boot from the Standard-SD slot since it is scanned first by the BootROM.
Some other background info: what Letux OS usually provides, is the minimum to make hardware completely useable. Letux OS is in its core a "board support package" provided by a hardware developer. Therefore it is severely limited by the number of people working on polishing things and providing patches.
So it looks as if the project soon needs a bigger kernel developer team to write such drivers (and fix other things) according to your (and others) preferences.
BR, Nikolaus
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aTc -
H. Nikolaus Schaller