Which is freely available Embedded Linux (including tool chains) for powerpc/ARM/MIPS?.
What special has Montavista Linux compare to other Embedded Linux's, why it is so popular, does anybody have any idea?. Appreciated.
The Best way to go on embedded linux is to use the open source linux instead of going to commercial linux.
There is no such thing as "commercial linux". There are commercial distributions, but the Linux kernel is open source, and any version of it that is distributed in any way *must* also be open source.
I didn't look at it, but it sounds good. Another example is to download the Linksys toolchain (actually developed by Broadcom) for MIPS development, or get it from any of the third parties offering firmware for the Linksys wireless routers.
Note that while that is specific to that platform, it is actually rather generic, and could easily be adapted to one or more other platforms. As it comes it can handle either MIPS or x86 targets, and can use either the uClibc or glibc libraries for the target. The host is restricted to Linux, and was written for an x86 based host but it probably would not be hard to convert it to some other Linux platform.
-- Floyd L. Davidson Ukpeagvik (Barrow, Alaska) floyd@apaflo.com
Montavista has nothing special, except its high price. AFAIK you can choice among these three options:
A. Proprietary commercial linux like MontaVista (
Happy hacking
--Shutruk
Another great distribution is the Embedded Linux Development Kit (ELDK) available at
It supports ARM, MIPS, and PowerPC. It has support for a wide variety of reference platforms and also provides their bootloader, U-Boot.
Chuck
Floyd,
If I download Linksys toolchain and then install it and then compile it, then can I directly download onto Linksys box, will I be able to write onro Linksys box?. Incase if something wrong happens, then I will loose the whole Router, Is there any reference design availble from Linksys which I can play with this tool chain?. Thanks in advance.
Yes. You can compile the firmware to be *exactly* the same as that provided by Linksys, or you can modify the source code. In either case the resulting firmware can be loaded to a WRT54G router using the "upgrade" functionality on the web interface. It's easy.
If you mean when the upgrade process fails (for example the router will not boot the new firmware), then yes you end up with a condition commonly referred to as "a brick"!
But, the good news is that Linksys designed several failsafe modes into the device, and others have been added by various third party firmware distributions. There are also two hardware modifications that can be made which greatly simplify recovery too.
The hardware modifications are to add an RS-232 serial port and to add access to an existing JTAG port. The serial port doesn't help with the above senario, but it does allow experimenting with configurations that lock up the Ethernet ports to be recovered from without a reboot. The JTAG port talks directly to the CPU, and can recover from virtually any type of firmware failure, as long as the hardware is functional.
The added features in third party firmware are a watchdog reboot function and a "boot_wait" feature that allows using TFTP protocols to be easily initiated during the boot process (it provides a ten second window when TFTP runs before the system boots).
The Linksys built in features are some default code in the flash ram that is not normally written to by the firmware upgrade process, which can be triggered externally to allow a TFTP process to take over instead of a reboot. (You have to open the case and short out two pins on the Flash RAM, which gives it a fault condition that triggers the TFTP process instead of the normal boot process.)
In other words, you just about *can't* destroy the unit with firmware upgrades unless you make a real effort at it (the JTAG port has the option of over writing to the wrong parts of the Flash RAM, and then only a JTAG connection would be able to restore it).
Well, I'm not sure what you mean. I'll tell you what I did... I searched eBay for used WRT54G's for sale, and bought a couple spares! I've got the goodies to add JTAG and the RS-232 port to one of them, but haven't done it yet. That will be my "test bed" unit. I have two units in service, and the other spare is a back up for those.
-- Floyd L. Davidson Ukpeagvik (Barrow, Alaska) floyd@apaflo.com
I wouldn't call the Montavista kernel "optimized". They have simply pre-selected a set of patches and provided them readily in place. You can apply them just the same on a non-MV kernel, although it takes a certain amount of clue.
The main reason you pay for MV is the support - when you've got a deadline and can't spare the time to figure out the cause of the problem yourself. Other than that, there's little reason.
I am new to embedded linux too. I am trying OpenEmbedded at the moment. And it does support ppc/arm/mips.
Minlin,
I heard OpenEmbedded comes with only Source code, none of the Toolchains available, also it supports Samsung ARM only, could you point me which reference design it supports, also the toolchain link to OpenEmbedded site, appreciated.
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