On 14:48 Thu 11 Jun , Nicolas Ferre wrote: > Hi, > > Aras Vaichas : > > Hi, > > > > we're designing our next generation RFID reader and I'm planning on > > using the AT91SAM9G20 in the next design. We currently use the > > AT91RM9200. > > Good choice ;-) > > > Can I get some feedback from people with regards to general design > > configurations that affect the boot time with respect to this CPU (or > > the AT91SAM9260) > > I presume that you already know what are the configurations we are using > at Linux4sam.org on our at91sam9g20ek board. Anyway, I answer your > questions as it may also interest other readers. > > > Some questions are: > > > > * what is your boot time? What is the time from power-on to kernel > > running, how long does the kernel take to run until init starts, and > > how long does init take? > > We have not tried to be clever on speeding up boot process but I guess > that we can save time: > - removing unneeded bootloader steps (remove u-boot for instance) > - removing unused drivers > - lower timeouts (Ethernet phy detection for example) > - tailor rootfs exactly to your needs > > That said, here are numbers from our not optimized demo > (AT91Bootstrap+u-boot+linux+buildroot): > - ~6s to Linux (can certainly be optimized) > - ~+2s to init > - ~+5s to login (here also) I've done some test on 9263 with the following config cpu+nor (u-boot+linux+busybox) ~4/5s to the prompt if the boottime is critical I'll recommend you NOR + XIP > > > * what is your system hardware configuration? CPU+NAND, CPU+NOR+NAND, > > CPU+DATAFLASH+NAND? > > CPU + NAND can lower your BOM > > > * do you boot everything from the NAND or do you use a combination of > > Dataflash/NOR and NAND? I've test it on 9263 > > Both. > > > * do you use U-Boot, or a minimal custom bootloader that copies a > > kernel image from NAND to SDRAM and then executes it? > > If boot time is a hot topic, choose AT91Bootstrap that directly loads Linux. I disagree on this because you will loose a lot's of possibity as bootcount DFU, store your kernel in your rootfs etc... > > > * do you mount a small partition of the NAND to begin with and then > > mount the rest later? > I'll consider to switch to UBIFS and use lzma compression (for the uImage) if no XIP Best Regards, J. -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
