Odroid-C1 regression with commit 4bc31edebde5 ("mmc: core: Set HS clock speed before sending HS CMD13")

[Ulf Hansson]

+ Shawn Lin, Luca Weiss

On Tue, 11 Apr 2023 at 01:13, Martin Blumenstingl
<martin.blumenstingl at googlemail.com> wrote:
>
> Hello Ulf,

Hi Martin,

Thanks for reporting - and my apologies for the long delay! It's been
a busy period with lots of travelling for me.

>
> today I found that upstream commit 4bc31edebde5 ("mmc: core: Set HS
> clock speed before sending HS CMD13") breaks eMMC support on my
> Odroid-C1.
> (yes, I know that I am very late to the party...)
>
> The .dts for this board is upstream using
> arch/arm/boot/dts/meson8b-odroidc1.dts (&sdhc node)
> The MMC host driver used is drivers/mmc/host/meson-mx-sdhc*.
>
> The problem I'm seeing is that the eMMC module is simply not detected.
> There are no errors in the kernel log (note that mmc1 is the eMMC
> while mmc0 is the SD card which is attached to another controller on
> that SoC):
> # dmesg | grep mmc
> [    2.742136] meson-mx-sdhc c1108e00.mmc: allocated mmc-pwrseq
> [    4.315905] platform c1108c20.mmc:slot at 1: Got CD GPIO
> [    4.450921] mmc0: new high speed SDHC card at address 0001
> [    4.456985] mmcblk0: mmc0:0001 EB1QT 29.8 GiB
> [    4.466108]  mmcblk0: p1
>
> In this state I get:
> # cat /sys/kernel/debug/mmc1/ios
> clock:          52000000 Hz
> actual clock:   51000000 Hz
> vdd:            21 (3.3 ~ 3.4 V)
> bus mode:       2 (push-pull)
> chip select:    0 (don't care)
> power mode:     2 (on)
> bus width:      3 (8 bits)
> timing spec:    9 (mmc HS200)
> signal voltage: 1 (1.80 V)
> driver type:    0 (driver type B)

It looks to me that we are in the process of enabling the HS200 mode,
but hangs at some point. Unless I am mistaken.

More precisely, I suspect it's either the call to mmc_set_clock() or
the call to mmc_switch_status(), in mmc_select_hs200(). Can you have a
closer look to confirm this?

>
> After reverting the mentioned commit I get:
> # dmesg | grep mmc
> [    2.744226] meson-mx-sdhc c1108e00.mmc: allocated mmc-pwrseq
> [    2.970944] mmc1: new HS200 MMC card at address 0001
> [    2.974492] mmcblk1: mmc1:0001 8GND3R 7.28 GiB
> [    2.985126]  mmcblk1: p1
> [    2.987810] mmcblk1boot0: mmc1:0001 8GND3R 4.00 MiB
> [    3.003007] mmcblk1boot1: mmc1:0001 8GND3R 4.00 MiB
> [    4.311754] platform c1108c20.mmc:slot at 1: Got CD GPIO
> [    4.374732] mmc0: new high speed SDHC card at address 0001
> [    4.377228] mmcblk0: mmc0:0001 EB1QT 29.8 GiB
> [    4.399152]  mmcblk0: p1
> # cat /sys/kernel/debug/mmc1/ios
> clock:          100000000 Hz
> actual clock:   94444445 Hz
> vdd:            21 (3.3 ~ 3.4 V)
> bus mode:       2 (push-pull)
> chip select:    0 (don't care)
> power mode:     2 (on)
> bus width:      3 (8 bits)
> timing spec:    9 (mmc HS200)
> signal voltage: 1 (1.80 V)
> driver type:    0 (driver type B)
>
> Please let me know which additional information would be helpful for
> debugging this further.
> Also I'd like to highlight that I'm not blaming the above commit
> (unless I know better). It's entirely possible that the meson-mx-sdhc
> driver (which I wrote) can be at fault and that I was previously just
> lucky.
>
> My git bisect log is:
> $ git bisect log
> git bisect start
> # status: waiting for both good and bad commits
> # good: [f443e374ae131c168a065ea1748feac6b2e76613] Linux 5.17
> git bisect good f443e374ae131c168a065ea1748feac6b2e76613
> # status: waiting for bad commit, 1 good commit known
> # bad: [4b0986a3613c92f4ec1bdc7f60ec66fea135991f] Linux 5.18
> git bisect bad 4b0986a3613c92f4ec1bdc7f60ec66fea135991f
> # good: [25fd2d41b505d0640bdfe67aa77c549de2d3c18a] selftests:
> kselftest framework: provide "finished" helper
> git bisect good 25fd2d41b505d0640bdfe67aa77c549de2d3c18a
> # good: [02e2af20f4f9f2aa0c84e9a30a35c02f0fbb7daa] Merge tag
> 'char-misc-5.18-rc1' of
> git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
> git bisect good 02e2af20f4f9f2aa0c84e9a30a35c02f0fbb7daa
> # good: [887f75cfd0da44c19dda93b2ff9e70ca8792cdc1] drm/amdgpu: Ensure
> HDA function is suspended before ASIC reset
> git bisect good 887f75cfd0da44c19dda93b2ff9e70ca8792cdc1
> # good: [cf424ef014ac30b0da27125dd1fbdf10b0d3a520] Merge tag
> 'for-5.18/fbdev-2' of
> git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev
> git bisect good cf424ef014ac30b0da27125dd1fbdf10b0d3a520
> # good: [4e707344e18525b4edf5c2bc2e3eb60692e8c92e] MAINTAINERS: add
> missing files for bonding definition
> git bisect good 4e707344e18525b4edf5c2bc2e3eb60692e8c92e
> # bad: [680b892685ea7043addb5819ddec9147d4263195] Merge branch
> '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/net-queue
> git bisect bad 680b892685ea7043addb5819ddec9147d4263195
> # bad: [e3de3a1cda5fdc3ac42cb0d45321fb254500595f] Merge tag
> 'powerpc-5.18-4' of
> git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
> git bisect bad e3de3a1cda5fdc3ac42cb0d45321fb254500595f
> # bad: [4b97bac0756a81cda5afd45417a99b5bccdcff67] Merge tag
> 'for-5.18-rc5-tag' of
> git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
> git bisect bad 4b97bac0756a81cda5afd45417a99b5bccdcff67
> # bad: [64267926e01b06f43e26232722fb3dc3f4819823] Merge tag
> 'mmc-v5.18-rc4' of
> git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc
> git bisect bad 64267926e01b06f43e26232722fb3dc3f4819823
> # good: [fe27d189e3f42e31d3c8223d5daed7285e334c5e] Merge tag
> 'folio-5.18f' of git://git.infradead.org/users/willy/pagecache
> git bisect good fe27d189e3f42e31d3c8223d5daed7285e334c5e
> # good: [ca5e2f4d6b677efa3f43a6790777e46dcf806e4d] Merge tag
> 'drm-misc-fixes-2022-05-05' of
> git://anongit.freedesktop.org/drm/drm-misc into drm-fixes
> git bisect good ca5e2f4d6b677efa3f43a6790777e46dcf806e4d
> # bad: [3e5a8e8494a8122fe4eb3f167662f406cab753b9] mmc: sdhci-msm:
> Reset GCC_SDCC_BCR register for SDHC
> git bisect bad 3e5a8e8494a8122fe4eb3f167662f406cab753b9
> # bad: [e9f3fb523dbf476dc86beea23f5b5ca8f9687c93] mmc: sunxi-mmc: Fix
> DMA descriptors allocated above 32 bits
> git bisect bad e9f3fb523dbf476dc86beea23f5b5ca8f9687c93
> # bad: [4bc31edebde51fcf8ad0794763b8679a7ecb5ec0] mmc: core: Set HS
> clock speed before sending HS CMD13
> git bisect bad 4bc31edebde51fcf8ad0794763b8679a7ecb5ec0
> # first bad commit: [4bc31edebde51fcf8ad0794763b8679a7ecb5ec0] mmc:
> core: Set HS clock speed before sending HS CMD13
>
>
> Thank you and best regards,
> Martin

Kind regards
Uffe