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by daivuk
Mon Jul 27, 2015 7:22 pm
Forum: Bare metal, Assembly language
Topic: Trying Bare Metal on Raspberry Pi 2
Replies: 98
Views: 32364

Re: Trying Bare Metal on Raspberry Pi 2

https://github.com/rsta2/circle/blob/master/lib/bcmframebuffer.cpp Thanks rst. I actually found out this morning that by substracting my address by 0xC0000000 fixed my problem. You are doing this: m_pInfo->BufferPtr & 0x3FFFFFFF It has the same effect. It's when you add GPU_MEM_BASE, which is 0xC00...
by daivuk
Mon Jul 27, 2015 6:53 pm
Forum: Bare metal, Assembly language
Topic: Screen01 lesson on RPi 2 B
Replies: 5
Views: 1219

Re: Screen01 lesson on RPi 2 B

Also, my code above is extremely slow. It takes about 1 second to fill the a framebuffer of 1680x1050. But I don't have a LDR in a tight loop, so I shouldn't get load hit store delays. Not sure why it's so low. I didn't expect the Raspberry Pi 2 to be that slow. I would gain a lot by using the GPU, ...
by daivuk
Mon Jul 27, 2015 6:48 pm
Forum: Bare metal, Assembly language
Topic: Screen01 lesson on RPi 2 B
Replies: 5
Views: 1219

Re: Screen01 lesson on RPi 2 B

I'll have to read more about caching on RPi2 before understanding your comment :) I thought caching worked that way: 1 - LDR from some address 2 - CPU loads a cache-line (64 next bytes or so) into L2/L1 cache So I am unsure why the framebuffer address being returned to me has something to do with ca...
by daivuk
Mon Jul 27, 2015 12:40 pm
Forum: Bare metal, Assembly language
Topic: Screen01 lesson on RPi 2 B
Replies: 5
Views: 1219

Re: Screen01 lesson on RPi 2 B

Just fixed it. I didn't find references anywhere about this, but if I understood the documentation better I might have caught up sooner :) The address coming back in my frame buffer info struct, has to be subtracted back by 0xC0000000. Probably to convert from DMA to ARM memory (Or something like th...
by daivuk
Mon Jul 27, 2015 12:54 am
Forum: Bare metal, Assembly language
Topic: Trying Bare Metal on Raspberry Pi 2
Replies: 98
Views: 32364

Re: Trying Bare Metal on Raspberry Pi 2

2. Old Frame Buffer code does not work, only MailBox Tags Frame Buffer works. The older way of setting the frame buffer, does not seem to exist on the Raspberry Pi 2. For me the older method works well. There must be another influence. Do you have any code samples? I've been stuck on that part for ...
by daivuk
Sun Jul 26, 2015 2:15 pm
Forum: Bare metal, Assembly language
Topic: Screen01 lesson on RPi 2 B
Replies: 5
Views: 1219

Screen01 lesson on RPi 2 B

Hi Everyone, This is my first post here. I got my Raspberry Pi 2 Model B last week, and ever since I am trying to follow the Baking PI Lessons to build my own OS. LED OK was hard to get working, but finally got it by finding resources here. The problem was the base address that had to be 0x3F000000....

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