[Qemu-devel] RE: Qemu-devel Digest, Vol 37, Issue 54

[Qemu-devel] RE: Qemu-devel Digest, Vol 37, Issue 54

[Schwarz, Konrad]

> Date: Tue, 18 Apr 2006 21:54:42 +0200
> From: Stefan Weil <weil@mail.berlios.de>
> Subject: [Qemu-devel] Flash simulation
> To: qemu-devel@nongnu.org
> Message-ID: <44454402.7030404@mail.berlios.de>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> A typical embedded system (and also most standard PCs) 
> contains flash memory. Full system emulation should also 
> emulate flash behaviour - not only read accesses but also 
> flash type discovery and flash programming.
> 
> Is there an easy way to realise flash memory emulation with 
> Qemu? Must I write this emulation from scratch?
> Hints how this might be done are welcome.

The QEMU memory interface is capable of supporting Flash emulation.
As far as I know, no ready solutions exist, so you need to do this from
scratch.

The data sheet of the Flash device you want to emulate documents the
commands the
device understands.  You need to implement the finite state machine
which interprets those commands.

A high-fidelity emulation will also simulate Flash erase and programming
times.

Regards,

Konrad Schwarz

[Qemu-devel] Flash devices

[Fabrice Bellard]

Schwarz, Konrad wrote:
>>Date: Tue, 18 Apr 2006 21:54:42 +0200
>>From: Stefan Weil <weil@mail.berlios.de>
>>Subject: [Qemu-devel] Flash simulation
>>To: qemu-devel@nongnu.org
>>Message-ID: <44454402.7030404@mail.berlios.de>
>>Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>>A typical embedded system (and also most standard PCs) 
>>contains flash memory. Full system emulation should also 
>>emulate flash behaviour - not only read accesses but also 
>>flash type discovery and flash programming.
>>
>>Is there an easy way to realise flash memory emulation with 
>>Qemu? Must I write this emulation from scratch?
>>Hints how this might be done are welcome.
> 
> 
> The QEMU memory interface is capable of supporting Flash emulation.
> As far as I know, no ready solutions exist, so you need to do this from
> scratch.
> 
> The data sheet of the Flash device you want to emulate documents the
> commands the
> device understands.  You need to implement the finite state machine
> which interprets those commands.
> 
> A high-fidelity emulation will also simulate Flash erase and programming
> times.

There is already an implementation of a flash device made by Jocelyn 
Mayer but I have not merged it yet because it needs an architectural 
change in QEMU concerning memory mapped I/Os. I'll try to make this 
change ASAP.

Fabrice.

Re: [Qemu-devel] Flash devices

[Stefan Weil]

Fabrice Bellard schrieb:

> Schwarz, Konrad wrote:
>
>>> Date: Tue, 18 Apr 2006 21:54:42 +0200
>>> From: Stefan Weil <weil@mail.berlios.de>
>>> Subject: [Qemu-devel] Flash simulation
>>> To: qemu-devel@nongnu.org
>>>
>>> A typical embedded system (and also most standard PCs) contains 
>>> flash memory. Full system emulation should also emulate flash 
>>> behaviour - not only read accesses but also flash type discovery and 
>>> flash programming.
>>>
>>> Is there an easy way to realise flash memory emulation with Qemu? 
>>> Must I write this emulation from scratch?
>>> Hints how this might be done are welcome.
>>
>>
>>
>>
>> The QEMU memory interface is capable of supporting Flash emulation.
>> As far as I know, no ready solutions exist, so you need to do this from
>> scratch.
>>
>> The data sheet of the Flash device you want to emulate documents the
>> commands the
>> device understands.  You need to implement the finite state machine
>> which interprets those commands.
>>
>> A high-fidelity emulation will also simulate Flash erase and programming
>> times.
>
>
>
> There is already an implementation of a flash device made by Jocelyn 
> Mayer but I have not merged it yet because it needs an architectural 
> change in QEMU concerning memory mapped I/Os. I'll try to make this 
> change ASAP.
>
> Fabrice.
>
Hello Fabrice,

I noticed the new code in QEMU HEAD and tried to use it, but my flash 
memory still behaves like
ordinary RAM even on write access.

Do you have a working example which uses the new flash driver or some 
hints which might help?

Thank you
Stefan