start_getty: Over added SERIAL_CONSOLE cause error in userspace log

Error log will be logged into /var/log/message.
Added in more condition checking on the script. Check
/proc/tty/drivers and /proc/tty/driver/*
file system to retrieve active targeted serial.
Only establish getty with active serial in runtime.

[YOCTO #10844]

Reviewed-by: Saul Wold <sgw@linux.intel.com>
(From OE-Core rev: ac0e9541fe93e866e42914f65a0516b993f0cffe)

Signed-off-by: Choong YinThong <yin.thong.choong@intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 34 insertions, 4 deletions

diff --git a/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty b/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
index e3d052a840..31b4413433 100644
--- a/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
+++ b/meta/recipes-core/sysvinit/sysvinit-inittab/start_getty
@@ -1,5 +1,35 @@
 #!/bin/sh
-if [ -c /dev/$2 ]
-then 
-        /sbin/getty -L $1 $2 $3
-fi
+####################################################################################
+# This script is use to automatic start serial console once power up.
+# Script enhancement has been done base on Bug YOCTO 10844.
+# Configuration can be done in meta/conf/machine/*.conf variable SERIAL_CONSOLES.
+# Most of the information is retrieve from /proc virtual filesystem which
+# contain all the runtime system information (eg. system memory, device mount, etc).
+####################################################################################
+
+# Get active serial filename.
+active_serial=$(grep "serial" /proc/tty/drivers | grep -oh "^\s*\S*")
+
+# Re-phrase input parameter from ttyS target index (ttyS1, ttyS2, ttyAMA0, etc).
+runtime_tty=$(echo $2 | grep -oh '[0-9]')
+
+for line in $active_serial; do
+        # File is availability, file content current active serial target index.
+        if [ -e /proc/tty/driver/$line ]
+        then
+                # File content a lot of unknown serial. We use -v to remove all unmatch and get left off.
+                # Tail use to avoid 1st line included into the filter because 1st line is file description.
+                activetty=$(grep -v "unknown" /proc/tty/driver/$line | tail -n +2 | grep -oh "^\s*\S*[0-9]")
+                for active in $activetty; do
+                        # Check if both index is match then proceed to enable the serial console.
+                        if [ $active -eq $runtime_tty ] 
+                        then
+                                if [ -c /dev/$2 ]
+                                then
+                                    /sbin/getty -L $1 $2 $3
+                                fi
+                                break
+                        fi
+                done
+        fi
+done