[Qemu-devel] IDE busmaster DMA support

[Qemu-devel] IDE busmaster DMA support

[GaLi]

Hi,

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 ?

Re: [Qemu-devel] IDE busmaster DMA support

[Hetz Ben Hamo]

Hi,

Which IDE driver do u try to write? for QEMU? or for a guest OS?

The IDE implementation of QEMU has few bugs (notice how the hack win2k
installation needs), so I would suggest to you to either try it with
BOCHS or with a trial version of VMWare.

Thanks,
Hetz

On 9/30/05, GaLi <g_cavelier@yahoo.fr> wrote:
>
> Hi,
>
> 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 ?
>
>
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel
>

Re: [Qemu-devel] IDE busmaster DMA support

[Juergen Keil]

> 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 

Re: [Qemu-devel] IDE busmaster DMA support

[GaLi]

It's an IDE driver for my own OS.

I don't think it comes from qemu because linux get it right. I tried to 
read linux source code but it's way too complicated.

I'll try in bochs and VMWare and tell you the results

Hetz Ben Hamo wrote:
> Hi,
> 
> Which IDE driver do u try to write? for QEMU? or for a guest OS?
> 
> The IDE implementation of QEMU has few bugs (notice how the hack win2k
> installation needs), so I would suggest to you to either try it with
> BOCHS or with a trial version of VMWare.
> 
> Thanks,
> Hetz
> 
> On 9/30/05, GaLi <g_cavelier@yahoo.fr> wrote:
> 
>>Hi,
>>
>>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 ?

Re: [Qemu-devel] IDE busmaster DMA support

[GaLi]

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 

Re: [Qemu-devel] IDE busmaster DMA support

[Lennert Buytenhek]

On Fri, Sep 30, 2005 at 12:15:04PM +0200, GaLi wrote:

> 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

If the least significant bit in a BAR is 1, it means that you're
dealing with I/O space (as opposed to memory space.)  For BARs
referencing I/O space, the upper 30 bits encode the address, and
for memory space BARs, the upper 28 bits encode the address.

So, 0xc001 means "I/O space BAR, base address 0xc000."


--L