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Subject: Re: [PATCH v2] arm64: dts: rockchip: Fix SD card init on
 rk3399-nanopi4
From:   =?utf-8?Q?Christian_Kohlsch=C3=BCtter?= 
        <christian@kohlschutter.com>
In-Reply-To: <eec07acea8694191a75880acc397dafe@hyperstone.com>
Date:   Thu, 14 Jul 2022 19:20:47 +0200
Cc:     Robin Murphy <robin.murphy@arm.com>,
        Markus Reichl <m.reichl@fivetechno.de>,
        =?utf-8?Q?Heiko_St=C3=BCbner?= <heiko@sntech.de>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-rockchip@lists.infradead.org" 
        <linux-rockchip@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linux MMC List <linux-mmc@vger.kernel.org>
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To:     Christian Loehle <CLoehle@hyperstone.com>
Precedence: bulk

> Am 14.07.2022 um 18:44 schrieb Christian Loehle =
<CLoehle@hyperstone.com>:
>=20
> I only briefly skimmed the discussion, but does this mean that a =
soft-reset (CMD0) of a UHS (post-voltage-switch) will not work?
> (As the card/spec requires a power-cycle by the host which will not =
come, right?)
> Can you try this real quick? I can give you a mmc-utils snippet if you =
have trouble issuing one.
> If that does indeed not work I think the general approach is to =
disable uhs in the dts or at least document that.
> Regards,
> Christian

I tried disabling UHS in the DTS, but that would still cause mmc =
detection issues.

"rmmod dw_mmc_rockchip" followed by "modprobe dw_mmc_rockchip" still =
detects the card:
> [ 4481.141764] mmc1: card 0001 removed
> [ 4488.133398] dwmmc_rockchip fe320000.mmc: IDMAC supports 32-bit =
address mode.
> [ 4488.133462] dwmmc_rockchip fe320000.mmc: Using internal DMA =
controller.
> [ 4488.133484] dwmmc_rockchip fe320000.mmc: Version ID is 270a
> [ 4488.133541] dwmmc_rockchip fe320000.mmc: DW MMC controller at irq =
32,32 bit host data width,256 deep fifo
> [ 4488.134320] dwmmc_rockchip fe320000.mmc: Got CD GPIO
> [ 4488.147329] mmc_host mmc1: Bus speed (slot 0) =3D 400000Hz (slot =
req 400000Hz, actual 400000HZ div =3D 0)
> [ 4488.218364] mmc_host mmc1: Bus speed (slot 0) =3D 148500000Hz (slot =
req 150000000Hz, actual 148500000HZ div =3D 0)
> [ 4488.678181] dwmmc_rockchip fe320000.mmc: Successfully tuned phase =
to 214
> [ 4488.678239] mmc1: new ultra high speed SDR104 SDHC card at address =
0001
> [ 4488.680315] mmcblk1: mmc1:0001 ASTC 14.6 GiB=20
> [ 4488.684871]  mmcblk1: p1 p2

Ejecting/re-inserting the card also works:
> [ 4607.521119] mmc1: card 0001 removed
> [ 4608.517343] mmc_host mmc1: Bus speed (slot 0) =3D 400000Hz (slot =
req 400000Hz, actual 400000HZ div =3D 0)
> [ 4608.632987] mmc_host mmc1: Bus speed (slot 0) =3D 148500000Hz (slot =
req 150000000Hz, actual 148500000HZ div =3D 0)
> [ 4609.065445] dwmmc_rockchip fe320000.mmc: Successfully tuned phase =
to 213
> [ 4609.065535] mmc1: new ultra high speed SDR104 SDHC card at address =
0001
> [ 4609.067942] mmcblk1: mmc1:0001 ASTC 14.6 GiB=20
> [ 4609.073521]  mmcblk1: p1 p2

and so is changing the clock back and forth:
> echo 400000 > /sys/kernel/debug/mmc1/clock; echo 150000000 > =
kernel/debug/mmc1/clock; fdisk -l /dev/mmcblk1

> [ 4817.829078] mmc_host mmc1: Bus speed (slot 0) =3D 400000Hz (slot =
req 400000Hz, actual 400000HZ div =3D 0)
> [ 4820.063457] mmc_host mmc1: Bus speed (slot 0) =3D 148500000Hz (slot =
req 150000000Hz, actual 148500000HZ div =3D 0)
> [ 4835.305419] dwmmc_rockchip fe320000.mmc: Successfully tuned phase =
to 213
> [ 4836.346928]  mmcblk1: p1 p2

Swapping with a "highspeed" (non-UHS) card also seems to work
> [ 5733.702083] mmc1: card 0001 removed
> [ 5738.858439] mmc_host mmc1: Bus speed (slot 0) =3D 400000Hz (slot =
req 400000Hz, actual 400000HZ div =3D 0)
> [ 5739.378487] mmc_host mmc1: Bus speed (slot 0) =3D 50000000Hz (slot =
req 50000000Hz, actual 50000000HZ div =3D 0)
> [ 5739.378627] mmc1: new high speed SD card at address 21bb
> [ 5739.380491] mmcblk1: mmc1:21bb APPSD 480 MiB=20
> [ 5739.382795] debugfs: Directory 'mmcblk1' with parent 'block' =
already present!
> [ 5739.385096]  mmcblk1: p1
> [ 5774.386536] FAT-fs (mmcblk1p1): utf8 is not a recommended IO =
charset for FAT filesystems, filesystem will be case sensitive!
> [ 5795.486365] mmc1: card 21bb removed
> [ 5801.302688] mmc_host mmc1: Bus speed (slot 0) =3D 400000Hz (slot =
req 400000Hz, actual 400000HZ div =3D 0)
> [ 5801.447128] mmc_host mmc1: Bus speed (slot 0) =3D 148500000Hz (slot =
req 150000000Hz, actual 148500000HZ div =3D 0)
> [ 5801.880374] dwmmc_rockchip fe320000.mmc: Successfully tuned phase =
to 211
> [ 5801.880440] mmc1: new ultra high speed SDR104 SDHC card at address =
0001
> [ 5801.882253] mmcblk1: mmc1:0001 ASTC 14.6 GiB=20
> [ 5801.884145] debugfs: Directory 'mmcblk1' with parent 'block' =
already present!
> [ 5801.886558]  mmcblk1: p1 p2
>=20

Some debug output: cat /sys/kernel/debug/mmc1/ios
UHC
> clock:		150000000 Hz
> actual clock:	148500000 Hz
> vdd:		18 (3.0 ~ 3.1 V)
> bus mode:	2 (push-pull)
> chip select:	0 (don't care)
> power mode:	2 (on)
> bus width:	2 (4 bits)
> timing spec:	6 (sd uhs SDR104)
> signal voltage:	1 (1.80 V)
> driver type:	0 (driver type B)
non-UHC
> cat /sys/kernel/debug/mmc1/ios
> clock:		50000000 Hz
> vdd:		18 (3.0 ~ 3.1 V)
> bus mode:	2 (push-pull)
> chip select:	0 (don't care)
> power mode:	2 (on)
> bus width:	2 (4 bits)
> timing spec:	2 (sd high-speed)
> signal voltage:	0 (3.30 V)
> driver type:	0 (driver type B)
>=20

How do I make sure I specifically send the soft-reset command? I'm happy =
to help but I'm really a novice here.

Best,
Christian