IMX8MM SD UHS support

[Adam Ford]

On Wed, Dec 30, 2020 at 12:47 PM Tim Harvey <tharvey at gateworks.com> wrote:
>
> On Wed, Dec 30, 2020 at 10:22 AM Adam Ford <aford173 at gmail.com> wrote:
> >
> > On Wed, Dec 30, 2020 at 11:50 AM Fabio Estevam <festevam at gmail.com> wrote:
> > >
> > > Hi Tim,
> > >
> > > On Wed, Dec 30, 2020 at 1:54 PM Tim Harvey <tharvey at gateworks.com> wrote:
> > >
> > > > Andrey,
> > > >
> > > > I did mention that I am using the imx8mm-evk. When I saw that my
> > > > custom board was having issues with sd_get_capabilities() I switched
> > > > to the imx8mm-evk and confirmed my findings there.
> > > >
> > > > I'm using master (ab865a8ee5c1) with imx8mm_evk_defconfig running on
> > > > an imx8mm-evk board configured via dip switches to boot from eMMC. I
> > > > have a SDR104 microSD which detects and operates as such in Linux and
> > > > this is what I see in U-Boot:
> > > >
> > > > U-Boot SPL 2021.01-rc4-00029-gab865a8 (Dec 30 2020 - 08:29:24 -0800)
> > > > Normal Boot
> > > > WDT:   Started with servicing (60s timeout)
> > > > Trying to boot from MMC2
> > > >
> > > >
> > > > U-Boot 2021.01-rc4-00029-gab865a8 (Dec 30 2020 - 08:29:24 -0800)
> > > >
> > > > CPU:   Freescale i.MX8MMQ rev1.0 at 1200 MHz
> > > > Reset cause: POR
> > > > Model: FSL i.MX8MM EVK board
> > > > DRAM:  2 GiB
> > > > WDT:   Started with servicing (60s timeout)
> > > > MMC:   FSL_SDHC: 1, FSL_SDHC: 2
> > > > Loading Environment from MMC... OK
> > > > In:    serial
> > > > Out:   serial
> > > > Err:   serial
> > > > Net:   eth0: ethernet at 30be0000
> > > > Hit any key to stop autoboot:  0
> > > > u-boot=> mmc dev 1
> > > > Run CMD11 1.8V switch
> > > > switch to partitions #0, OK
> > > > mmc1 is current device
> > > > u-boot=> mmc info
> > > > Device: FSL_SDHC
> > > > Manufacturer ID: 1b
> > > > OEM: 534d
> > > > Name: 00000
> > > > Bus Speed: 50000000
> > > > Mode: SD High Speed (50MHz)
> > > > Rd Block Len: 512
> > > > SD version 3.0
> > > > High Capacity: Yes
> > > > Capacity: 14.9 GiB
> > > > Bus Width: 4-bit
> > > > Erase Group Size: 512 Bytes
> > > >
> > > > You can see that the 1.8V switch succeeds and the card is recognized
> > > > as high-speed but does not show the SDR104 capability.
> > >
> > > Could you please test this patch from Adam?
> > > https://patchwork.ozlabs.org/project/uboot/patch/20201230173907.2891555-1-aford173@gmail.com/
> >
> > My patch probably won't do much more than the one from Andrey.  From
> > what I could gather, the generic mmc driver uses those flags to enable
> > the host caps.  My enables the same host caps by checking the
> > structure so the device tree flags are not needed.
> >
> > The UHS and HS200/HS400 config options need to be enabled in Kconfig
> > for them to make a difference.  Part of me wonders if they should be
> > implied-on if USHDC is set, but that's a different issue.
> >
> > If Tim is not seeing the SDR104 negotiated from Andrey's patch, it
> > probably won't change with mine.
> >
>
> Right, the issue is not the host caps.
>
> If I enable the calls to mmc_dump_capabilities() I see:
> u-boot=> mmc info
> Device: FSL_SDHC
> Manufacturer ID: 3
> OEM: 5344
> Name: SL16G
> Bus Speed: 50000000
> Mode: SD High Speed (50MHz)
> card capabilities: widths [4, 1] modes [MMC legacy, SD High Speed
> (50MHz), UHS SDR12 (25MHz), UHS SDR25 (50MHz)]
> 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: 14.8 GiB
> Bus Width: 4-bit
> Erase Group Size: 512 Bytes
>
> You can see above the host shows DDR50/SDR104 capability but the card
> does not. Again, the issue is in sd_get_capabilities()
>
> Adam / Fabio, what results do you see on your board(s)?

My eMMC appears to work properly at HS400ES, and that was my focus,
but I am seeing similar results on the SD card as you are.

u-boot=> mmc info
Device: FSL_SDHC
Manufacturer ID: 27
OEM: 5048
Name: SD32G
Bus Speed: 50000000
Mode: SD High Speed (50MHz)
card capabilities: widths [4, 1] modes [MMC legacy, SD High Speed
(50MHz), UHS SDR12 (25MHz), UHS SDR25 (50MHz)]
host capabilities: widths [4, 1] modes [MMC legacy, MMC High Speed
(26MHz), SD High Speed (50MHz), MMC High Speed (52MHz), UHS SDR12
(25MHz), UHS SDR25 (50MHz), UHS SDR50 (100MHz), UHS DDR50 (50MHz), UHS
SDR104 (208MHz), HS200 (200MHz), HS400 (200MHz), HS400ES (200MHz)]
Rd Block Len: 512
SD version 3.0
High Capacity: Yes
Capacity: 29 GiB
Bus Width: 4-bit
Erase Group Size: 512 Bytes
u-boot=>

It doesn't appear to be able to properly negotiate the SDR104 from the
SD card, but the host is showing the proper host capabilities.  I'm
looking into the sd card query now.  I don't have the full spec, but
I'll try to compare it against the Linux driver.

adam
>
> Tim