6.7-stable review patch. If anyone has any objections, please let me know.
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From: Stephan Gerhold stephan@gerhold.net
commit 4bbda9421f316efdaef5dbf642e24925ef7de130 upstream.
The blsp_dma controller is shared between the different subsystems, which is why it is already initialized by the firmware. We should not reinitialize it from Linux to avoid potential other users of the DMA engine to misbehave.
In mainline this can be described using the "qcom,controlled-remotely" property. In the downstream/vendor kernel from Qualcomm there is an opposite "qcom,managed-locally" property. This property is *not* set for the qcom,sps-dma@7884000 [1] so adding "qcom,controlled-remotely" upstream matches the behavior of the downstream/vendor kernel.
Adding this seems to fix some weird issues with UART where both input/output becomes garbled with certain obscure firmware versions on some devices.
[1]: https://git.codelinaro.org/clo/la/kernel/msm-3.10/-/blob/LA.BR.1.2.9.1-02310...
Cc: stable@vger.kernel.org # 6.5 Fixes: 61550c6c156c ("arm64: dts: qcom: Add msm8939 SoC") Signed-off-by: Stephan Gerhold stephan@gerhold.net Reviewed-by: Bryan O'Donoghue bryan.odonoghue@linaro.org Link: https://lore.kernel.org/r/20231204-msm8916-blsp-dma-remote-v1-2-3e49c8838c8d... Signed-off-by: Bjorn Andersson andersson@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/boot/dts/qcom/msm8939.dtsi | 1 + 1 file changed, 1 insertion(+)
--- a/arch/arm64/boot/dts/qcom/msm8939.dtsi +++ b/arch/arm64/boot/dts/qcom/msm8939.dtsi @@ -1682,6 +1682,7 @@ clock-names = "bam_clk"; #dma-cells = <1>; qcom,ee = <0>; + qcom,controlled-remotely; };
blsp_uart1: serial@78af000 {