From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jerry Van Baren Date: Mon, 17 Dec 2007 08:38:44 -0500 Subject: [U-Boot-Users] [Fwd: Re: reducing size of u-boot binary] In-Reply-To: <1197700077.2679.16.camel@root> References: <1197700077.2679.16.camel@root> Message-ID: <47667BE4.3070700@ge.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de vibi wrote: > On Fri, 2007-12-14 at 07:20 -0500, Jerry Van Baren wrote: >> vibi wrote: >>> hello, >>> can any one please tell me how to reduce the size of u-boot.bin. >>> i tried by disabling commands in the >>> include/config/at91rm9200dk.h,as per the read me document >>> even after this when i compile,i was unable to decrease the >>> size. >>> >>> thanks in advance. >>> >>> regards >>> vibi sreenivasan >> How big is your binary, why do you need to reduce its size? I ask >> because most of the time this question is the result of a link gone bad >> where part of the linked binary lives in low memory space and part lives >> in high memory space. As a result, the .bin has a huge amount of filled >> (unused) data between the two. >> >> Best regards, >> gvb > > dear jerry, > thanks for your reply.i am using u-boot 1.1.5 .my binary is only 90kb & > i still wanted to reduce the size.i thought compiling u-boot is like > compiling linux kernel,ie source file for the disabled commands wont get > compiled,now i understood that i was wrong. > > i wanted to reduce size to less than 90kb because of constraints in > available flash memory space. > > i have done it by disabling bootp & rarp by using #define macros > i didnt find option for that in /include/cmd_confdefs.h . > > once again i thank you for your response > > thanks & regards > vibi sreenivasan Hi Vibi, 90K is already pretty small for a u-boot image. I don't know how small u-boot can get, but rule of thumb is 128K is a reasonable size for good functionality. With respect to the commands, disabling commands should cut the actual command code out via #ifdefs, so disabling commands should result in a smaller image, even though all the files are still compiled. a) There is a limit to how much can be cut out by removing commands. There still is a lot of support code necessary. b) It is possible that a command that is disabled needs a support function, but the support function isn't disabled so not all the potential savings are realized. Note that u-boot is going to a better configuration and linking methodology that doesn't compile unused pieces (as opposed to compiling code that is #ifdefed out). I don't expect this to save any significant amount of memory, but it is possible that it will turn up and fix errors or inefficiencies with the current method. Best regards, gvb