The dwmmc controllers on rk3188 do not have idma support, so need to
use the fifo-mode and it my tests they became confused and stopped
working if the frequency was to high.
While I only tested in somewhat bigger steps, 32MHz for example
hung the controller, while reducing it to 16MHz worked just fine
and is reasonably fast to load a kernel from mmc.
Signed-off-by: Heiko Stuebner <he...@sntech.de>
---
arch/arm/dts/rk3188-radxarock-u-boot.dtsi | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/arch/arm/dts/rk3188-radxarock-u-boot.dtsi
b/arch/arm/dts/rk3188-radxarock-u-boot.dtsi
index 013535abcd..1bb5408592 100644
--- a/arch/arm/dts/rk3188-radxarock-u-boot.dtsi
+++ b/arch/arm/dts/rk3188-radxarock-u-boot.dtsi
@@ -11,6 +11,21 @@
u-boot,dm-spl;
};
+&mmc0 {
+ fifo-mode;
+ max-frequency = <16000000>;
+};
+
+&mmc1 {
+ fifo-mode;
+ max-frequency = <16000000>;
+};
+
+&emmc {
+ fifo-mode;
+ max-frequency = <16000000>;
+};
+
&uart2 {
status = "okay";
u-boot,dm-spl;
--
2.18.0
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