scripts: add EVA ramboot script

Use the EVA bootloader to load a small linux system into the ram and boot
it from there:

  ./scripts/flashing/eva_ramboot.py 192.168.178.1 path/to/initramfs-kernel.bin

Signed-off-by: Valentin Spreckels <Valentin.Spreckels@Informatik.Uni-Oldenburg.DE>
Acked-by: John Crispin <john@phrozen.org>
[reworded commit message]
Signed-off-by: Mathias Kresin <dev@kresin.me>

scripts/flashing/eva_ramboot.py

@@ -0,0 +1,37 @@
+#!/usr/bin/python
+
+from ftplib import FTP
+from sys import argv
+from os import stat
+
+assert len(argv) == 3
+ip = argv[1]
+image = argv[2]
+
+size = stat(image).st_size
+# arbitrary size limit, to prevent the address calculations from overflows etc.
+assert size < 0x2000000
+
+# We need to align the address. A page boundary seems to be sufficient on 7362sl
+# and 7412
+addr = ((0x8000000 - size) & ~0xfff)
+haddr = 0x80000000 + addr
+img = open(image, "rb")
+
+ftp = FTP(ip, 'adam2', 'adam2')
+
+def adam(cmd):
+	print("> %s"%(cmd))
+	resp = ftp.sendcmd(cmd)
+	print("< %s"%(resp))
+	assert resp[0:3] == "200"
+
+ftp.set_pasv(True)
+# The following parameters allow booting the avm recovery system with this
+# script.
+adam('SETENV memsize 0x%08x'%(addr))
+adam('SETENV kernel_args_tmp mtdram1=0x%08x,0x88000000'%(haddr))
+adam('MEDIA SDRAM')
+ftp.storbinary('STOR 0x%08x 0x88000000'%(haddr), img)
+img.close()
+ftp.close()