support: cn913x: Collect DRAM ECC status

On platforms based on CN913{0,1,2}, collect all ECC related counters
so that we know if any correctable errors have been encountered since
the most recent boot.

Author: wkz

board/aarch64/rootfs/usr/share/product/marvell,armada-ap807/etc/support.d/50-marvell-cn913x.sh

@@ -0,0 +1,26 @@
+#!/bin/sh
+
+set -e
+
+ecc_stat()
+{
+    local chan=
+    local base=
+
+    for chan in 0 1; do
+        base=$((0xf0020360 + 0x200 * chan))
+
+        echo "DRAM Channel $chan ECC Status"
+        echo -n "  Log config: "; devmem $((base + 0x0)) 32
+        echo -n "  1b errors:  "; devmem $((base + 0x4)) 32
+        echo -n "  Info 0:     "; devmem $((base + 0x8)) 32
+        echo -n "  Info 1:     "; devmem $((base + 0xc)) 32
+        echo
+    done
+}
+
+[ -n "$1" ] || { echo "usage: $0 OUT-DIR"; exit 1; }
+work="$1"/marvell-cn913x
+mkdir -p "${work}"
+
+ecc_stat >"${work}"/ecc-stat