Re: [Qemu-devel] IDE busmaster DMA support

[GaLi <g_cavelier@yahoo.fr>]

OK, thank you very much.

GaLi

Juergen Keil wrote:
>>I'm trying to write an IDE driver with busmaster DMA support.
>>My problem is that I can't get the right controller registers addresses.
>>
>>In the IDE BusMaster DMA specification :
>>
>>"The control registers for the controller are allocated via the
>>devices Base Address register at offset 0x20 in PCI configuration
>>space."
>>
>>If I read the word at offset 0x20 in the PCI configuration space, I get 
>>0xc001. But if I boot qemu with a linux live-cd, it tells me that BM-DMA 
>>is at 0xc000
>>
>>Do I have to init the PCI IDE controller or something ?
> 
> 
> Bit 0 encodes if the registers are in IO (1) or in memory (0) space.
> You get the IO base address by using a 0xfffffffe mask.
> 
> For memory space the mask is 0xfffffff0, the low four bits encode
> a few memory properties (prefetch, 32-bit vs. 64-bit memory addresses).
> 
> See the PCI spec for more details. Or for example the PCI_BASE_* defines here:
> 
>   http://cvs.opensolaris.org/source/xref/usr/src/uts/common/sys/pci.h#519