6.1-stable review patch. If anyone has any objections, please let me know.
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From: Stephan Gerhold stephan@gerhold.net
[ Upstream commit 7c45b6ddbcff01f9934d11802010cfeb0879e693 ]
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: a0e5fb103150 ("arm64: dts: qcom: Add msm8916 BLSP device nodes") 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-v1-1-3e49c8838c8d... Signed-off-by: Bjorn Andersson andersson@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/boot/dts/qcom/msm8916.dtsi | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/arm64/boot/dts/qcom/msm8916.dtsi b/arch/arm64/boot/dts/qcom/msm8916.dtsi index f0d097ade84c..987cebbda057 100644 --- a/arch/arm64/boot/dts/qcom/msm8916.dtsi +++ b/arch/arm64/boot/dts/qcom/msm8916.dtsi @@ -1522,6 +1522,7 @@ blsp_dma: dma-controller@7884000 { clock-names = "bam_clk"; #dma-cells = <1>; qcom,ee = <0>; + qcom,controlled-remotely; };
blsp1_uart1: serial@78af000 {