[OpenWrt-Devel] [PATCH] WDR4900v1 remove dt node for absent hw crypto.

[Tim Small]

The WDR4900v1 uses the P1040 SoC, so the device tree pulls in the
definition for the related P1010 SoC.  However, the P1040 lacks the
CAAM/SEC4 hardware crypto accelerator which the P1010 device tree
defines.  If left defined, this causes the CAAM drivers (if present) to
attempt to use the non-existent device, making various crypto-related
operations (e.g. macsec and ipsec) fail.

This commit overrides the incorrect dt node definition in the included
file.

See also:
 - https://bugs.openwrt.org/index.php?do=details&task_id=1262
 - https://community.nxp.com/thread/338432#comment-474107

Signed-off-by: Tim Small <tim at seoss.co.uk>
---
 .../files/arch/powerpc/boot/dts/tl-wdr4900-v1.dts  | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/target/linux/mpc85xx/files/arch/powerpc/boot/dts/tl-wdr4900-v1.dts b/target/linux/mpc85xx/files/arch/powerpc/boot/dts/tl-wdr4900-v1.dts
index c2444936b7..bde5eb9575 100644
--- a/target/linux/mpc85xx/files/arch/powerpc/boot/dts/tl-wdr4900-v1.dts
+++ b/target/linux/mpc85xx/files/arch/powerpc/boot/dts/tl-wdr4900-v1.dts
@@ -236,3 +236,27 @@
 };
 
 /include/ "fsl/p1010si-post.dtsi"
+
+/*
+ * The TL-WDR4900 v1 uses the NXP (Freescale) P1014 SoC which is closely
+ * related to the P1010.
+ *
+ * NXP QP1010FS.pdf "QorIQ P1010 and P1014 Communications Processors"
+ * datasheet states that the P1014 does not include the accelerated crypto
+ * module (CAAM/SEC4) which is present in the P1010.
+ *
+ * NXP Appliation Note AN4938 Rev. 2 implies that some P1014 may contain the
+ * SEC4 module, but states that SoCs with System Version Register values
+ * 0x80F10110 or 0x80F10120 do not have the security feature.
+ *
+ * All v1.3 TL-WDR4900 tested have SVR == 0x80F10110 which AN4938 describes
+ * as: core rev 1.0, "P1014 (without security)".
+ *
+ * The SVR value is reported by uboot on the serial console.
+ */
+
+/ {
+	soc: soc at ffe00000 {
+		/delete-node/ crypto at 30000; /* Pulled in by p1010si-post */
+	};
+};
-- 
2.11.0


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