On Monday 06 April 2009 15:49:43 Wolfgang Denk wrote:
In message Scott Wood wrote:
There are tons of standards for image formats, and even more commonly used formats I would not dare to call standard; but this processor has to invent yet another one?
The same could be said about u-boot requiring its own image format (ELF and raw binary images can't be passed a device tree or bd_t, AFAICT).
When the U-Boot (or rather PPCBoot at that time) development was starte, there was a very important reason for not using ELF: wasting a full 64 kB for the standard ELF file header was unthinkable on most embedded devices of that time.
Now, on fat systems with ample resource on one side, and on the other side with the infrastructure more or less in place to compose a bootm command from small, separate building blocks, it should be not difficult to add such a feature, too.
On the other hand, ELF images are missing a few key points available in U-Boot images so I would not recommend using plain ELF for any system where reliability or just ease of use are important (which was the other part of the rationale that led to that format).
which are the same reasons processors do not implement support for ELF as a booting source ...
lets say i was to design a brand new part today with an on-chip rom that supports booting from a variety of sources (UART, SPI/I2C/NAND flashes, directly addressable NOR flashes, as a slave device to SPI/I2C, etc...), what format would you recommend that could satisfy all of these requirements ? i'm not aware of any which is why the Blackfin processor has its own stripped down LDR format. -mike