On Mon, Sep 12, 2016 at 05:18:53PM +0800, Peng Fan wrote:
On Mon, Sep 12, 2016 at 05:07:58PM +0800, Peng Fan wrote:
We should not use "bi_dram[0].start + text_offset" as the image dst. The text_offset maybe 0 for some images, such as XEN. Then the dst is actually bi_dram[0].start, which maybe the location of spin table.
Let's use "images->ep & ~(ih->text_offset)" as the dst address.
This patch maybe not that correct according to the doc from Linux kernel. " The Image must be placed text_offset bytes from a 2MB aligned base address anywhere in usable system RAM and called there. The region between the 2 MB aligned base address and the start of the image has no special significance to the kernel, and may be used for other purposes. "
Now I do not have a good idea that we may have a spin table in the start of DRAM or even a small firmware.
Is it better to change gd->bd->bi_dram[0].start? For example physical dram starts from 0x80000000, but 4K is reserved at the beginning. So is it ok to change gd->bd->bi_dram[0].start to 0x80001000?
So, to be more precise, with v4.5 the memory location restrictions were relaxed. So we first need to update cmd/booti.c to know that res1 is now 'flags' and that we must check bit3 to determine where / how to align the image. In the case of bit3 == 0 we must continue to do what we do today. In the case of bit3 == 1, we have to decide what exactly to do. My first thought is to see if images->ep is 2MB aligned and if so move to images->ep + ih->text_offset. If not 2MB aligned, align that and then add ih->text_offset.
Then any areas that need to be reserved in memory, wherever they are, can still be marked off as reserved in the DT.