Re: [Qemu-devel] [PATCH] block: mask NOR flash buffered write length

[Peter Maydell]

On 18 October 2013 14:54, Roy Franz <address@hidden> wrote:
> On Fri, Oct 18, 2013 at 6:36 AM, Peter Maydell <address@hidden> wrote:
>> Probably instead of a single "width" property we should have two,
>> similar to the device tree binding's pair:
>>  - bank-width : Width (in bytes) of the bank.  Equal to the
>>    device width times the number of interleaved chips.
>>  - device-width : (optional) Width of a single mtd chip.  If
>>    omitted, assumed to be equal to 'bank-width'.

>> However I'm not very familiar with how flash hardware works...
>     You are correct - we really do want to mask based on the device
> width, as that is what the
> actual flash chips will see.  Lacking the device width I used the
> writeblock size.  Thinking about this more,
> this will not work for 8 bit devices used together, as the mask size
> will be greater than 8 bits and the writeblock size
> will be mis-interpreted like it is now.
> I'll work on adding a device-size property to the pflash*
> implementations.  It looks like this will affect about 20 platforms.
> For the platforms that I am not familiar with I plan just set
> bank-width==device-width as that should result in the unchanged
> behavior.

Yes, you should make the default for the device-width property
be to be the same as the bank-width, since that's what we
currently implement; then we can just change the platforms
where we know that's wrong.

NB: probably best to leave the existing 'width' property with
the name it has, rather than renaming it to 'bank-width'.

thanks
-- PMM