sam0_sdhc: SDXC cards are not detected / handled properly

[benpicco]

Description

A 64 GB SDXC card shows issues with the sam0_sdhc driver.
It works fine with sdcard_spi.

The root cause is that sam0_sdhc and sdcard_spi both implement the bigh level and low level SD card interface on their own.

It appears that the high level interface of sdcard_spi is more complete whereas sam0_sdhc fails to detect the SDXH card (it doesn't even enable block addressing).

Ideally the high level code could be shared across drivers.

Steps to reproduce the issue

Insert a SD card > 32 GB. Try tests/mtd_raw or formatting the file system.

Expected results

test <id> works with tests/mtd_raw, format creates a valid file system.

Actual results

Test and format both get stuck.

Versions

[benpicco]

OK, this is weird. I didn't change anything, now it just works

2022-08-16 21:40:59,478 # Manual MTD test
2022-08-16 21:40:59,481 # init MTD_0… OK (32 MiB)
2022-08-16 21:40:59,485 # init MTD_1… OK (256 byte)
2022-08-16 21:40:59,679 # init MTD_2… OK (60906 MiB)
> test 2
2022-08-16 21:41:15,499 # [START]
2022-08-16 21:41:15,521 # [SUCCESS]

[maribu]

... now it just works

Maybe bad wiring? Let's close this for now, until we have indication that there indeed is an issue.

Or maybe the issue also got fixed as side-affect of fixing the driver on 8-bit platforms?

[benpicco]

Or maybe the issue also got fixed as side-affect of fixing the driver on 8-bit platforms?

This is about the native SD host controller driver for the sam0 platform, not the generic SPI one.

[maribu]

Oh yes, indeed. Sorry for the confusion 😅