newbie to embedded linux on arm
in [Embedded]
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From: Ulf Samuelsson on 18 Dec 2009 18:04 tamamontu skrev 2009-12-17 14:09: >> One of the easiest ways to get a complete Linux thing together is to >> download >> "Buildroot" from www.buildroot.org >> >> You need a Linux machine and git. (or download a tarball) >> >> make at91sam9263ek_defconfig >> make >> >> Wait a few hours and then you have >> >> * Cross Compiler >> * First level Bootloader (at91bootstrap) >> * Second level bootloader (U-Boot) >> * Linux Kernel >> * Root file system >> * Scripts for U-boot environment >> >> The Samsung chips are not supported. >> By building for another ARM chip, you can use the root fs, >> but you have to build the bootloader and kernel manually. >> >> Alternatively, you can switch to a chip which IS supported well by >> Buildroot (Read AT91s) >> Note that the vanilla Buildroot is lagging for AT91. >> I have an experimental version based on the Buildroot 2009.08 release >> > which > >> uses the latest 2.6.32 kernel. It is located in the private git area of >> the Buildroot project. >> Less tested than the vanilla stuff, but if you want to try the latest... >> This also allows building the newer SAM9G45& G10, which the vanilla >> version does not. >> >> There are limitations to Buildroot, and I have started to use >> OpenEmbedded www.openembedded.org. >> When I tried building a full system with X and Gnome on the top, >> it took 42 hours on my 2 GHz Pentium M laptop. >> >> I built myself a 2.66GHz Core i7 machine this spring, and on this >> > machine > >> (8 virtual cores) it takes about 2 hours to complete the same job. >> It builds a cross compiler in about 10 minutes :-) >> > > Thanks for your replies and info on the books. > > Ulf Thanks for explaining the steps in volved in this kind of project. > > At my work place we have a board which uses Cirrus Logic EP9307 chip + 5.6" > touch screen. I have been asked to work on this project. > > I want to develop a touch screen based application which will control some > peripheral device over CAN bus. > There is really very little support for the EP93 series in Buildroot. You can do what you want with an AT91SAM9263, and then it is more or less automatic with Buildroot. > http://www.ibm.com/developerworks/library/l-embdev.html > This link has a good explanation also. > > > If I am not wrong buildroot is a gui based con-fig file generation utility > > When you say to manually compile the kernel and bootloader. Can you please > give pointer to understand how it is done. > You can study the source code for the AT91SAM9263 build recipes in buildroot for starters. > cheers > tama > > > > > > --------------------------------------- > This message was sent using the comp.arch.embedded web interface on > http://www.EmbeddedRelated.com > -- Best Regards Ulf Samuelsson These are my own personal opinions, which may or may not be shared by my employer Atmel Nordic AB
From: Ulf Samuelsson on 18 Dec 2009 18:09 Vladimir Vassilevsky skrev 2009-12-18 15:10: > > > David Brown wrote: >> Vladimir Vassilevsky wrote: >>> Grant Edwards wrote: >>>> On 2009-12-16, Vladimir Vassilevsky <nospam(a)nowhere.com> wrote: >>>>> tama wrote: >>>>> >>>>> >>>>> >>>>>> I want to learn linux/ embedded linux. >>>>> >>>>> >>>>> Book: >>>>> >>>>> P. Raghavan, A. Lad, S. Neelakandan >>>>> "Embedded Linux System Design and Development" >>>> >>>> >>>> >>>> The O'Reilly book is also good: >>>> >>>> Yaghmour, Masters, Ben-Yossef, and Gerum >>>> "Building Embedded Linux Systems" >>> >>> >>> Actually, having read the first book, I was very dissapointed about >>> Linux and ended up rolling my own OS. >>> >> >> The OS you describe is a totally different beast than Linux - your OS >> and Linux solve very different problems and are suitable for very >> different applications. If what you needed was something like the OS >> you wrote (and presumably it was!), then of course Linux would be a >> disappointment. > > I don't understand the idea of embedded linix. What is it useful for? > What is so good about it? > > VLV How much code does your SSH implementation take? How much code does your SAMBA server take? Do you have a driver for a capacitive touch sensor? How many users can log into your machine? Do you support all Wacom tablets or only a few? List goes on and on and on. Both Linux and RTOS'es have their applicability -- Best Regards Ulf Samuelsson These are my own personal opinions, which may or may not be shared by my employer Atmel Nordic AB
From: Ulf Samuelsson on 18 Dec 2009 18:13 Vladimir Vassilevsky skrev 2009-12-18 15:56: > > > Grant Edwards wrote: >> On 2009-12-18, Vladimir Vassilevsky <nospam(a)nowhere.com> wrote: >> >> >>> I don't understand the idea of embedded linix. What is it useful for? >> >> >> It's useful when you need a Linux/Unix OS in an embedded >> project. For example: you want to run a reasonably >> full-featured web server, > > But who may need full featured embedded web server? > >> you need an ssh server, ssl support, >> IPv4 and IPv6 support with NAT and firewall features, DHCP >> server and client, NTP server and client, and stuff like that. > > On embedded linix without memory management? Only idiots run Linux without MMU today. You can get an ARM9 with MMU for less than what you used to pay for an 8051. > > Don't know about ssl/ssh, IPv6 is large, the other abovementioned > things are no big deal. > >>> What is so good about it? >> >> >> It's free. > > Please, not again. It is not free. It is free, in the respect that you have full access to the internals. It is free to aqcuire, not to maintain. > >> It works. > > Kinda. After you spend ~months to make it work. > >> There's a lot of software that runs on >> it. > > Yes, there are few useful utilities, some of these indeed work very well. > >> It's been ported to everyting under the sun. > > I still don't understand the fascination with it. Douglas Adams explained it with "Share and Enjoy!" > Vladimir Vassilevsky > DSP and Mixed Signal Design Consultant > http://www.abvolt.com -- Best Regards Ulf Samuelsson These are my own personal opinions, which may or may not be shared by my employer Atmel Nordic AB
From: Nobody on 18 Dec 2009 22:32
On Sat, 19 Dec 2009 00:13:11 +0100, Ulf Samuelsson wrote: >> On embedded linix without memory management? > > Only idiots run Linux without MMU today. That's a bit extreme. An MMU-less system doesn't make much sense if you are running a lot of user-space software, but in the case where you have a single program (which happens to need a substantial OS beneath it), the lack of an MMU isn't much of an issue. |