Re: [PATCH 3/4] remoteproc: add support for a new 64-bit trace version

[ClÃment Leger]

Hi Suman,

----- On 22 May, 2020, at 19:33, Bjorn Andersson bjorn.andersson@xxxxxxxxxx wrote:

> On Fri 22 May 09:54 PDT 2020, Suman Anna wrote:
> 
>> On 5/21/20 2:42 PM, Suman Anna wrote:
>> > Hi Bjorn,
>> > 
>> > On 5/21/20 1:04 PM, Bjorn Andersson wrote:
>> > > On Wed 25 Mar 13:47 PDT 2020, Suman Anna wrote:
> [..]
>> > > > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> [..]
>> > > > +struct fw_rsc_trace2 {
>> > > 
>> > > Sounds more like fw_rsc_trace64 to me - in particular since the version
>> > > of trace2 is 1...
>> > 
>> > Yeah, will rename this.
>> > 
>> > > 
>> > > > +ÂÂÂ u32 padding;
>> > > > +ÂÂÂ u64 da;
>> > > > +ÂÂÂ u32 len;
>> > > > +ÂÂÂ u32 reserved;
>> > > 
>> > > What's the purpose of this reserved field?
>> > 
>> > Partly to make sure the entire resource is aligned on an 8-byte, and
>> > partly copied over from fw_rsc_trace entry. I guess 32-bits is already
>> > large enough of a size for trace entries irrespective of 32-bit or
>> > 64-bit traces, so I doubt if we want to make the len field also a u64.
>> 
>> Looking at this again, I can drop both padding and reserved fields, if I
>> move the len field before da. Any preferences/comments?

Not only the in structure alignment matters but also in the resource table.
Since the resource table is often packed (see [1] for instance), if a


[1] https://github.com/OpenAMP/open-amp/blob/master/apps/machine/zynqmp_r5/rsc_table.h

>> 
> 
> Sounds good to me.
> 
> Thanks,
> Bjorn