[openwrt/openwrt] mvebu: disable cpu idle on WRT1900ACv1

[LEDE Commits]

nbd pushed a commit to openwrt/openwrt.git, branch master:
https://git.lede-project.org/5faa9556b1c10a4b21208615bddb7480401fa213

commit 5faa9556b1c10a4b21208615bddb7480401fa213
Author: Felix Fietkau <nbd at nbd.name>
AuthorDate: Mon Mar 19 21:58:12 2018 +0100

    mvebu: disable cpu idle on WRT1900ACv1
    
    A regression seriously affecting the Linksys WRT1900ACv1 (Mamba) was
    introduced some time between the OpenWrt/LEDE v4.4 and v4.9 kernels.
    The root cause has not yet been identified, despite many attempts for
    more than a year. Disabling the SoC specific CPU idle support should
    mitigate this issue.
    
    The symptoms on an affected system are unwanted reboots at a variable
    frequency. In many cases almost immediately after boot, causing a
    bootloop.  This effectively disables support for Mamba on OpenWrt
    with kernels > v4.4.
    
    Signed-off-by: Felix Fietkau <nbd at nbd.name>
---
 .../patches-4.14/230-armada-xp-linksys-mamba-broken-idle.patch | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/target/linux/mvebu/patches-4.14/230-armada-xp-linksys-mamba-broken-idle.patch b/target/linux/mvebu/patches-4.14/230-armada-xp-linksys-mamba-broken-idle.patch
new file mode 100644
index 0000000..e82a899
--- /dev/null
+++ b/target/linux/mvebu/patches-4.14/230-armada-xp-linksys-mamba-broken-idle.patch
@@ -0,0 +1,10 @@
+--- a/arch/arm/boot/dts/armada-xp-linksys-mamba.dts
++++ b/arch/arm/boot/dts/armada-xp-linksys-mamba.dts
+@@ -563,3 +563,7 @@
+ 		};
+ 	};
+ };
++
++&coherencyfab {
++	broken-idle;
++};