eMMC card - Intel Atom E3800 - Another UefI issue

[matute81]

Hello,
I'm continuing my war with UEFI, but I'm not completely sure that's its fault this time...
I'm developing on a board equiped with an eMMC card, no flash disk or SATA disk.
Reading the Intel Atom e3800 specifications I found that eMMC controller is on PCI at bus 0, device 0x17, fun 0.
Executing "pci" command in efi shell I saw the device in that position.
When I take control of the system and disable Uefi boot services I try to detect PCI devices and my list is the same of the previous list (retrieved via EFI shell) except for 2 devices: SDIO controller and eMMC controller.
My PCI searching function is good, no problem there.
Someone could explain me why I'm not able to see this devices on PCI and how can I find them (eMMC in particular)?

Thank you,
Regards

Daniele

[jtokarchuk]

[misread SDIO as SDO, editted this out]

The term eMMC is short for "embedded Multi-Media Controller" and refers to a package consisting of both flash memory and a flash memory controller integrated on the same silicon die. This is commonly used in UEFI

-- here's an explanation on where it's used: https://msdn.microsoft.com/en-us/librar ... 85%29.aspx

That's the general knowledge, I'm afraid I lack the experience to implement it though. Perhaps someone else will chime in.

[matute81]

I found a setting in the BIOS about these devices:
South Cluster config --> LPSS & SCC config--> Device mode -> PCI/ACPI

Setting ACPI I'm not able to see the devices qith a PCI scan, otherwise setting PCI I'm able to.
If somebody know more about finding these devices in both mode I'll be very happy to learn something!
Bye

[mallard]

SDO usually stands for "Serial Data Out" -- which is commonly found on an audio controller (Serial data line, it's twin brother is SDI, serial data in.)

That may be, but the device in question is an "SDIO controller", which is something rather different...

[jtokarchuk]

SDO usually stands for "Serial Data Out" -- which is commonly found on an audio controller (Serial data line, it's twin brother is SDI, serial data in.)

That may be, but the device in question is an "SDIO controller", which is something rather different...

bah, correct you are. reading fail.

[Octocontrabass]

Setting ACPI I'm not able to see the devices qith a PCI scan, otherwise setting PCI I'm able to.
If somebody know more about finding these devices in both mode I'll be very happy to learn something!

The PCI mode makes the devices appear on the PCI bus as PCI devices.

Therefore, I expect the ACPI mode makes the devices appear in the ACPI tables, which would require you to implement ACPI in order to locate them.

[matute81]

Yes, that's true.
My priority now is implenting a basic driver for eMMC,that looks not so easy...
have you got any knowledge about that device?

[rdos]

I've done a SD card device driver, but the specifications are horrible, and there is a huge amount of "variability" that seems to serve no purpose whatsoever. When I tried to run my driver with a new SD card it failed, and so did it when I tried another computer. If it is really an SDIO device, rather than a SD card, you are in for even more problems.

Given a choice, I'd select a computer that had other alternative disc interfaces, like IDE or AHCI. Even USB flash is cleaner and less problematic than SD cards.

[matute81]

Hi,
I agree rdos.
I'm trying to write a basic driver for emmc card.
Using intel controller it should be less "random", I hope it can works with the most of devices.
I've both AHCI and IDE driver but my hardware engineer seems to have fun changing the cards on the table

I'm working using the intel atom e3800 specification and Jedec emmc standard. Do you know these specifications?
They look unclear in some part (as usual I'd say) but the protocol seems less complicated than AHCI

Bye,
Daniele