[U-Boot-Users] Optimized U-boot : Optimization of UCC and TFTP codes of UBOOT
Sandeep.Kumar at freescale.com
Tue Nov 21 10:15:49 CET 2006
Thank you for the immediate reply to my mail but in my
case I will not be using the entire U-boot and hence not bothered about
the total size of U-boot. We already have a "startup code" for our board
and this startup code runs from the I2CPROM. Once the start up code gets
executed, the next step is to initialize the Ethernet driver and then
run Tftp over this. The ipaddr, serverip, etc., will be hard coded.
The startup code basically does some register initialization required to
up the board. Another point here is that the user will not be able to
access the serial console till the board downloads the images and boots
Now, the startup code contains a function call to the Ethernet driver
initialization which actually sets up the Ethernet driver and then over
this Tftp support is provided to download the kernel images to the RAM.
So, in this case I need not use the entire U-boot and I require only the
ucc_geth.c, ucc_fast.c, ucc_geth_phy.c and the corresponding header
files for the Ethernet initialization and
tftp.c, eth.c and net.c and some other supportive functions. The size of
libucc.a is around 44KB and that of libnet.a is around 42KB and I need
to optimize these codes providing minimal features. The size of the
startup code is less than 1KB
and the rest of the code should fit in the rest of 17KB.
So, any ideas on how to proceed with this feature of booting from PROM,
plz do share them with me.
From: wd at denx.de [mailto:wd at denx.de]
Sent: Tuesday, November 21, 2006 2:02 PM
To: KUMAR GOPALPET-B05799
Cc: u-boot-users at lists.sourceforge.net
Subject: Re: [U-Boot-Users] Optimized U-boot : Optimization of UCC and
TFTP codes of UBOOT
<1034141BCEB1424784F14A38BD006D82165BB5 at zin33exm22.fsl.freescale.net>
> I am currently trying to optimize the Ethernet driver
> initialization code and the Tftp code of the U-boot so that it can fit
> into the I2CPROM of the 8321 LCDB board whose PROM size is 32 KB, but
> out of which only 18 KB is available for the code.
I recommend to check code and data sizes of a few objects in the
U-Boot tree, and to re-consiser if it is worth to spent effort on
> do bare initialization of the Ethernet and does not implement any
> complex functionalities. The only functions that are required are the
> (1) TX event (2) RX event (3) Error Control and (4)CRC.
Yes, and you will need initialization of the CPU, the RAM (for stack and
I/O buffers, and you will need support for the environment and code to
read it (for things like MAC address), and you may want to be able to
see what's happening, so a minimal serial driver is needed, which in
turn asks for things like printf, and... and...
> The Tftp code (present in the net directory of the U-Boot) then should
> support a simple file transfer protocol implemented in a minimal
Right. That's what the initiual 'T' stands for. I don;t think that the
current code is overly bloated.
> The Ethernet initialization code and the Tftp code size should not be
> more than 18 KB.
Let's give it a quick check on a TQM834x system:
-> size cpu/mpc83xx/*.o net/*.o lib_generic/string.o
text data bss dec hex filename
468 24 0 492 1ec cpu/mpc83xx/cpu.o
304 0 0 304 130 cpu/mpc83xx/cpu_init.o
1868 8 0 1876 754 cpu/mpc83xx/i2c.o
104 0 0 104 68 cpu/mpc83xx/interrupts.o
0 0 0 0 0 cpu/mpc83xx/resetvec.o
0 0 0 0 0 cpu/mpc83xx/spd_sdram.o
1260 248 0 1508 5e4 cpu/mpc83xx/speed.o
14584 92 0 14676 3954 cpu/mpc83xx/start.o
1804 76 0 1880 758 cpu/mpc83xx/traps.o
2296 120 0 2416 970 net/bootp.o
2588 76 12 2676 a74 net/eth.o
6528 324 204 7056 1b90 net/net.o
4784 208 2224 7216 1c30 net/nfs.o
576 48 0 624 270 net/rarp.o
0 0 0 0 0 net/sntp.o
2220 196 52 2468 9a4 net/tftp.o
1256 4 0 1260 4ec lib_generic/string.o
3032 24 0 3056 bf0 lib_generic/vsprintf.o
Just this fraction of the U-Boot code gives a total of more than 44 kB.
I doubt that you can optimize away 60% of this...
Software Engineering: Embedded and Realtime Systems, Embedded Linux
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
The rule on staying alive as a program manager is to give 'em a num-
ber or give 'em a date, but never give 'em both at once.
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