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arm64: dts: qcom: sm8450: Enable UHS-I SDR50 and SDR104 SD card modes

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The reported problem of some non-working UHS-I speed modes on SM8450
originates in commit 0a631a36f7 ("arm64: dts: qcom: Add device tree
for Sony Xperia 1 IV"), and then it was spread to all SM8450 powered
platforms by commit 9d561dc4e5 ("arm64: dts: qcom: sm8450: disable
SDHCI SDR104/SDR50 on all boards").

The tests show that the rootcause of the problem was related to an
overclocking of SD cards, and it's fixed later on by commit a27ac3806b
("clk: qcom: gcc-sm8450: Use floor ops for SDCC RCGs").

Since then both SDR50 and SDR104 speed modes are working fine on SM8450,
tested on SM8450-HDK:

SDR50 speed mode:

    mmc0: new UHS-I speed SDR50 SDHC card at address 0001
    mmcblk0: mmc0:0001 00000 14.6 GiB
     mmcblk0: p1

    % dd if=/dev/mmcblk0p1 of=/dev/null bs=1M count=1024
    1024+0 records in
    1024+0 records out
    1073741824 bytes (1.1 GB, 1.0 GiB) copied, 24.6254 s, 43.6 MB/s

SDR104 speed mode:

    mmc0: new UHS-I speed SDR104 SDHC card at address 59b4
    mmcblk0: mmc0:59b4 USDU1 28.3 GiB
     mmcblk0: p1

    % dd if=/dev/mmcblk0p1 of=/dev/null bs=1M count=1024
    1024+0 records in
    1024+0 records out
    1073741824 bytes (1.1 GB, 1.0 GiB) copied, 12.3266 s, 87.1 MB/s

Remove the restrictions on SD card speed modes from the SM8450 platform
dtsi file and enable UHS-I speed modes.

Fixes: 9d561dc4e5 ("arm64: dts: qcom: sm8450: disable SDHCI SDR104/SDR50 on all boards")
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Link: https://lore.kernel.org/r/20260314023715.357512-5-vladimir.zapolskiy@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
This commit is contained in:
Vladimir Zapolskiy 2026-03-14 04:37:13 +02:00 • committed by Bjorn Andersson
commit db0c5ef1ab
1 changed files with 0 additions and 3 deletions
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