arm64: dts: qcom: msm8916: Make blsp_dma controlled-remotely

commit 7c45b6ddbcff01f9934d11802010cfeb0879e693 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.1.2.9.1-02310-8x16.0/arch/arm/boot/dts/qcom/msm8916.dtsi#L1466-1472

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@gerhold.net
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/boot/dts/qcom/msm8916.dtsi b/arch/arm64/boot/dts/qcom/msm8916.dtsi
index 3c934363368c32f6e88476b6ed43a8354057f579..961ceb83a91faee4882864849572ba2e91bac92e 100644 (file)
--- a/arch/arm64/boot/dts/qcom/msm8916.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8916.dtsi
@@ -2085,6 +2085,7 @@
                        clock-names = "bam_clk";
                        #dma-cells = <1>;
                        qcom,ee = <0>;
+                       qcom,controlled-remotely;
                };
 
                blsp_uart1: serial@78af000 {