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Hi,
Please explain to me what is exactly JFFS2 ? Where can I get it ? How can I compile that filesystem to use on uClinux ? And how can I use it instead of the romfs which can be built using the Linux Filesystem Project from NIOS II IDE ? Thanks for ideas. Dmitry.Link Copied
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Hi Dmitry,
> Please explain to me what is exactly JFFS2 ? Journaling Flash File System II. Here's a very good starting point: http://www.enseirb.fr/~kadionik/embedded/u.../howto_mtd.html (http://www.enseirb.fr/~kadionik/embedded/uclinux/mtd/howto_mtd.html) > Where can I get it ? It's already in the Microtronix distribution. > How can I compile that filesystem to use on uClinux ? Enable JFFS2 when configuring the kernel. You'll need an appropriate mtd mapping driver and chip driver. If you're using CFI flash, you can use the one (or both) of the CFI chip drivers already in the source tree. > And how can I use it instead of the romfs which can be built using the > Linux Filesystem Project from NIOS II IDE ? This is a bit more involved & it's much easier if you have a linux development platform (e.g. RH9). Basically, you create a directory tree on your development system that contains all of the inodes (regular, special, etc) that you want for your Nios system, then use the mkfs.jffs2 utility to create a binary image that you program into your flash. BTW: If you're using the AMDLV065D, you'll probably have to deal with the "erase" bug in the CFI chip driver ... I haven't had time to look at the code yet ... so I got lazy & just used cramfs instead ;-) Regards, --Scott- Mark as New
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<div class='quotetop'>QUOTE </div>
--- Quote Start --- BTW: If you're using the AMDLV065D, you'll probably have to deal with the "erase" bug in the CFI chip driver ... I haven't had time to look at the code yet ... so I got lazy & just used cramfs instead ;-)[/b] --- Quote End --- Can you tell more about this bug? Thanks,- Mark as New
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Hi wentao,
> Can you tell more about this bug? Ouch ... I need to find my notes on this ;-) Basically it was more of a 'hardware issue' ... rather than a software bug. As I recall it was related to the the polling method used during erase/erase-suspend operations -- and the state of the toggle bit ... This motivated me to switch to cramfs (which BTW works great). Since upgrading to the latest Microtronix kernel, I haven't looked through the CFI chip driver code ... perhaps it was already addressed. But with the previous kernel I had problems. Regards, --Scott- Mark as New
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Hi Scott,
Your notes remind me that we did run into that problem related with the toggling bit, which does not work because of the way Avalon bus works. We modified that driver to use the polling bit instead, for Nios systems. The modification is included in the last release. Thanks and Regards, wentao- Mark as New
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Hi wentao,
> We modified that driver to use the polling bit instead, for Nios systems. > The modification is included in the last release. Great! It's time for me to switch back then -- thanks :-) Regards, --Scott
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