Problem got solved...
One of my senior mate asked me to
mknod into the /dev by,
mknod /dev/mmcblk0 179 0
mknod /dev/mmcblk0p1 179 1
mknod /dev/mmcblk0p2 179 2
mknod /dev/mmcblk0p3 179 3
and things worked fine for me...
Being newbie... I thought that linux is detecting devices itself and makes the files accordingly