[PATCH 6.1 178/197] arm64: dts: qcom: msm8916: Make blsp_dma controlled-remotely

Greg Kroah-Hartman
2024-02-20T21:07:13Z

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.1.2.9.1-02310-8x16.0/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: 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 {
--
2.43.0