On 10 March 2016 at 03:56, Aurelio Remonda <aurelio.remo...@tallertechnologies.com> wrote: > > > On Mon, Mar 7, 2016 at 8:37 PM, Peter Maydell <peter.mayd...@linaro.org> > wrote: >> >> On 8 March 2016 at 02:58, Aurelio Remonda >> <aurelio.remo...@tallertechnologies.com> wrote: >> > Hello, sorry for taking so long, I am working on this again. >> > About your last response, I was looking at the struct >> > stellaris_board_info >> > ,which contains >> > dc0, and this entire struct is const. If we need to calculate dc0 based >> > on >> > the provided RAM size >> > or default value at least the dc0 field should not be const. >> >> Yes, certainly. >> >> You might also need to look at the magic hex numbers in >> the stellaris_board[] array -- one is labelled /* dc0 */ >> so might be related. > > Thanks Peter! > I have a question about the set_memory_options function, when the m flag is > present, this function takes the size value (or the default_ram_size) and > perform > an QEMU_ALIGN_UP. Let's say you want the board default ram_size, the default > dc0 value should be 0xff00 (65280) when the align is made this value becomes > 0x00ffff (65535). This align will make the dc0 value change, so I have to > make some > operations on ram_size so dc0 will be as exact as it should. > > Something like this: > ram_size |= ((ram_size-1)>>8); > board->dc0 |= (ram_size & 0xffff)<<16; > On stellaris_init function > > Then the sram_size and the flash_size are exposed like always. I change the > magic hex numbers > in the stellaris_board[] array from 0x00ff007f to 0x0000007f as the > flash_size > will not change even with the flag. The default_ram_size is also changed for > this board to > be 64K on lm3s6965evb_class_init func: > mc->default_ram_size = 0x0000ff00; > > What do you think of this approach? Thank you!
You should reject unworkable ram sizes rather than silently changing what the user asked for; this matches our preferred approach where the user asks for more RAM than the board can support. thanks -- PMM
