[PATCH v2 2/4] arm64: dts: qcom: sc7180: Mark SCM as dma-coherent for IDP

[Douglas Anderson]

sc7180-idp is, for most intents and purposes, a trogdor device.
Specifically, sc7180-idp is designed to run the same style of firmware
as trogdor devices. This can be seen from the fact that IDP has the
same "Reserved memory changes" in its device tree that trogdor has.

Recently it was realized that we need to mark SCM as dma-coherent to
match what trogdor's style of firmware (based on TF-A) does [1]. That
means we need this dma-coherent tag on IDP as well.

Without this, on newer versions of Linux, specifically those with
commit 7bd6680b47fa ("Revert "Revert "arm64: dma: Drop cache
invalidation from arch_dma_prep_coherent()"""), WiFi will fail to
work. At bootup you'll see:

  qcom_scm firmware:scm: Assign memory protection call failed -22
  qcom_rmtfs_mem 94600000.memory: assign memory failed
  qcom_rmtfs_mem: probe of 94600000.memory failed with error -22

[1] https://lore.kernel.org/r/20230615145253.1.Ic62daa649b47b656b313551d646c4de9a7da4bd4@changeid

Fixes: 7bd6680b47fa ("Revert "Revert "arm64: dma: Drop cache invalidation from arch_dma_prep_coherent()""")
Fixes: f5ab220d162c ("arm64: dts: qcom: sc7180: Add remoteproc enablers")
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---
I realized that this needed to be in IDP as well and that the IDP
patch actually needed to come _before_ the trogdor one given the order
that things landed upstream. I still left most of the description of
the problem in the trogdor patch, though. Hopefully that's OK.

Changes in v2:
- sc7180-IDP patch added for v2.

 arch/arm64/boot/dts/qcom/sc7180-idp.dts | 5 +++++
 arch/arm64/boot/dts/qcom/sc7180.dtsi    | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/qcom/sc7180-idp.dts b/arch/arm64/boot/dts/qcom/sc7180-idp.dts
index 9f052270e090..299ef5dc225a 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-idp.dts
+++ b/arch/arm64/boot/dts/qcom/sc7180-idp.dts
@@ -393,6 +393,11 @@ &remoteproc_mpss {
 	qcom,spare-regs = <&tcsr_regs_2 0xb3e4>;
 };
 
+&scm {
+	/* TF-A firmware maps memory cached so mark dma-coherent to match. */
+	dma-coherent;
+};
+
 &sdhc_1 {
 	status = "okay";
 
diff --git a/arch/arm64/boot/dts/qcom/sc7180.dtsi b/arch/arm64/boot/dts/qcom/sc7180.dtsi
index f479cab8ab45..a65be760d1a7 100644
--- a/arch/arm64/boot/dts/qcom/sc7180.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180.dtsi
@@ -369,7 +369,7 @@ CLUSTER_SLEEP_0: cluster-sleep-0 {
 	};
 
 	firmware {
-		scm {
+		scm: scm {
 			compatible = "qcom,scm-sc7180", "qcom,scm";
 		};
 	};
-- 
2.41.0.162.gfafddb0af9-goog