On 01/10/2014 12:39 PM, Kevin O'Connor wrote: > On Thu, Jan 09, 2014 at 01:46:19AM -0600, mrnuke wrote: >> It's essential for some ARM SoCs. Allwinner chips like the MMC as their >> first boot source, and people are very happy with having their firmware >> and linux on micro SD. It makes the system unbrickable. > > Can you expand on this requirement? Do these machines have a regular > flash/rom with code that reads the rest of the firmware from the block > device, or is some portion of the block device mapped by hardware at > startup and that portion is tasked with reading the rest of the > firmware off the block device? If so, how big is the initial mapped > area? >
A blob built-in the SoC reads in some of the firmware (from SD, MMC or SPI, load to SRAM @ 0x0, branch to 0x0). 24 KiB on A10, a little different on A13 and so on. Think of it as the coreboot bootblock. That's all the free ride that you get. romstage and others you have to load manually. -- coreboot mailing list: [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
