Greetings,
In 50b1a69cee0d ("ARM: dts: imx8m: add UHS or HS400/HS400ES properties") u-boot dt props were added to enable UHS and HS400 on a couple of IMX8MM boards including the imx8mm-evk and in the subsequent patch enabled the config items.
While I see this making a huge difference for eMMC performance in U-Boot I find it doesn't do anything for microSD performance.
The issue appears to be that sd_get_capabilities() is not appropriately detecting UHS speeds on cards that appropriately detect as SDR104/DDR50 in Linux:
u-boot=> mmc info Device: FSL_SDHC Manufacturer ID: 1b OEM: 534d Name: 00000 Bus Speed: 50000000 Mode: SD High Speed (50MHz) card capabilities: widths [4, 1] modes [MMC legacy, SD High Speed (50MHz)] ^^^^ no SDR104 detected for this card host capabilities: widths [4, 1] modes [MMC legacy, MMC High Speed (26MHz), SD High Speed (50MHz), MMC High Speed (52MHz), UHS DDR50 (50MHz), UHS SDR104 (208MHz)] Rd Block Len: 512 SD version 3.0 High Capacity: Yes Capacity: 14.9 GiB Bus Width: 4-bit Erase Group Size: 512 Bytes
The same card in Linux shows the following upon insertion and performance tests show that it is operating at SDR104 speeds: mmc1: new ultra high speed SDR104 SDHC card at address 0001
I haven't found very good documentation on the SD switch settings to understand if something is wrong in the U-Boot implementation of of sd_get_capabilities() and I suppose it also could be an issue in sdhci-esdhc-imx.c.
Any ideas where to look?
Anyone see SDR104 cards being detected properly for other platforms?
Best regards,
Tim