Alexander Stein wrote:
Hello,
Am Donnerstag, 29. Juli 2010, 08:25:53 schrieb Reinhard Meyer:
You have add interrupt handling (write source) to AT91 in general and provide a patch for that.
But first you have to define why you need interrupts (in the u-boot phase) in the first place.
One reason would be to workaround errata 44.3.5.1 (RSTC: Reset During SDRAM Accesses) on the AT91SAM9G20 which traps the reset interrupt to shutdown the SDRAM controller properly -.-
This problem exists in the 9260 and 9G20, I wonder if the 9XE has it, too (its not documented there). However it would only prevent initial boot from external NOR or NAND flash. I am not sure if anyone does that... And -what if- a short brownout triggers a reset, but the SDRAM chips don't reset their state machines?
Then, that particular IRQ would not mean enabling IRQs for other devices in u-boot. I would probably add the code in such a manner (board.c) that it does not need CONFIG_USE_IRQ defined.
Reinhard