[console speed] Inherit console speed from install environment (#1987)

* pick up console speed from install enviroment

* get console speed from /proc/cmdline

* add CONSOLE_PORT handle

installer/x86_64/install.sh

@@ -64,11 +64,6 @@ fi
 
 echo "onie_platform: $onie_platform"
 
-# default console settings
-CONSOLE_PORT=0x3f8
-CONSOLE_DEV=0
-CONSOLE_SPEED=9600
-
 # Get platform specific linux kernel command line arguments
 ONIE_PLATFORM_EXTRA_CMDLINE_LINUX=""
 
@@ -77,6 +72,36 @@ VAR_LOG_SIZE=4096
 
 [ -r platforms/$onie_platform ] && . platforms/$onie_platform
 
+# Pick up console port and speed from install enviroment if not defined yet.
+# Console port and speed setting in cmdline is like "console=ttyS0,9600n",
+# so we can use pattern 'console=ttyS[0-9]+,[0-9]+' to match it.
+# If failed to get the speed and ttyS from cmdline then set them to default: ttyS0 and 9600
+if [ -z "$CONSOLE_PORT" ]; then
+    console_ttys=$(cat /proc/cmdline | grep -Eo 'console=ttyS[0-9]+' | cut -d "=" -f2)
+    if [ -z "$console_ttys" -o "$console_ttys" = "ttyS0" ]; then
+        CONSOLE_PORT=0x3f8
+        CONSOLE_DEV=0
+    elif [ "$console_ttys" = "ttyS1" ]; then
+        CONSOLE_PORT=0x2f8
+        CONSOLE_DEV=1
+    elif [ "$console_ttys" = "ttyS2" ]; then
+        CONSOLE_PORT=0x3e8
+        CONSOLE_DEV=2
+    elif [ "$console_ttys" = "ttyS3" ]; then
+        CONSOLE_PORT=0x2e8
+        CONSOLE_DEV=3
+    fi
+fi
+
+if [ -z "$CONSOLE_SPEED" ]; then
+    speed=$(cat /proc/cmdline | grep -Eo 'console=ttyS[0-9]+,[0-9]+' | cut -d "," -f2)
+    if [ -z "$speed" ]; then
+        CONSOLE_SPEED=9600
+    else
+        CONSOLE_SPEED=$speed
+    fi
+fi
+
 # Install demo on same block device as ONIE
 if [ "$install_env" != "build" ]; then
     onie_dev=$(blkid | grep ONIE-BOOT | head -n 1 | awk '{print $1}' |  sed -e 's/:.*$//')