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Topic: Linux kernel record to the physical address. How?

I write the driver for not which  (video card). It is necessary  the data from  in storage of the device. I do here under this description (probably it too old): http://www.tldp.org/LDP/khg/HyperNews/g … xlate.html I Do here so: char * baseptr = ioremap (0xFC000000, 1024*1024);/* write a ' A ' to the offset 10 of the area *///actually here//here I should write down a cycle in video storage mbyte,//which begins with physical 0xFC000000 writeb address (' A ', baseptr+10);/* unmap when we unload the driver */iounmap (baseptr); And happens nothing. Well that is,  works, the screen is lit, but on the screen a chaotic mash of points. Images are not present. Without  (and any other OS) the same  works. I WRITE to the necessary area of storage, the picture is. It means that hardware problems are not present. A kernel 2.6.* (I Know that different versions of a kernel can have different mechanisms of operation with storage) Help to understand! Is better stick with the link.

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Re: Linux kernel record to the physical address. How?

Hello, alpha21264, you wrote: A> I Do here so: A> A> char * baseptr = ioremap (0xFC000000, 1024*1024); A> By sight you made all correctly. And whence this magic constant 0xFC000000 undertook? Perhaps, in it a problem?

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Re: Linux kernel record to the physical address. How?

Hello, Pzz, you wrote: Pzz> Hello, alpha21264, you wrote: A>> I Do here so: A>> A>> char * baseptr = ioremap (0xFC000000, 1024*1024); A>> Pzz> By sight you made all correctly. And whence this magic constant 0xFC000000 undertook? Perhaps, in it a problem? This information to me was informed a voice by the developer of a video card. Our card, and the processor too ours. We want to make own litsenzionno-pure computer of type Raspberry. And to read about it something it is possible? In any business there is 1001 big and small cunning. Book Linux Device Drivers read. But there about  it is written very little.

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Re: Linux kernel record to the physical address. How?

pci/pcie ? At first it is necessary to receive the address in storage where pci the arbitrator selects to you and then already there take to write for an example any video the driver  and disassemble in a rare occurence everyones  pieces of iron can resolve here and so on a straight line to write where I would want what to receive a profit

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Re: Linux kernel record to the physical address. How?

Hello, alpha21264, you wrote: Pzz>> By sight you made all correctly. And whence this magic constant 0xFC000000 undertook? Perhaps, in it a problem? A> this information to me was informed a voice by the developer of a video card. And it is what address, physical or bus address? At 32-bit x86 they normally coincide, and at other architecture are not present is more often. ioremap' it is necessary bus address. A> And to read about it something it is possible? Ask that easier. I read source codes of other drivers. And when it is not clear, source codes of those functions of a kernel to which they address. A> in any business there is 1001 big and small cunning. A> book Linux Device Drivers read. It is good to read this book in a toilet to pass away long winter evenings. It easy also is read pleasantly. But in it a little that is told.

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Re: Linux kernel record to the physical address. How?

Hello, alpha21264, you wrote: Understood already or still is not present?