Re: [PATCH v1] xen/arm: arm32: Add support to identify the Cortex-R52 processor

[Julien Grall <julien@xxxxxxx>]

Hi Ayan,

On 20/06/2023 19:28, Ayan Kumar Halder wrote:
> On 20/06/2023 17:41, Julien Grall wrote:
> > Hi,
> Hi Julien,
> > On 20/06/2023 16:17, Ayan Kumar Halder wrote:
> > > Add a special configuration (CONFIG_AARCH32_V8R) to setup the Cortex-R52
> > > specifics.
> > >
> > > Cortex-R52 is an Arm-V8R AArch32 processor.
> > >
> > > Refer ARM DDI 0487I.a ID081822, G8-9647, G8.2.112 MIDR,
> > > bits[31:24] = 0x41 , Arm Ltd
> > > bits[23:20] = Implementation defined
> > > bits[19:16] = 0xf , Arch features are individually identified
> > > bits[15:4] = Implementation defined
> > > bits[3:0] = Implementation defined
> > >
> > > Thus, the processor id is 0x410f0000 and the processor id mask is
> > > 0xff0f0000
> > >
> > > Also, there is no special initialization required for R52.
> > Are you saying that Xen upstream + this patch will boot on Cortex-R52?
> This patch will help for earlyboot of Xen. With this patch, cpu_init() 
> will work on Cortex-R52.
> There will be changes required for the MPU configuration, but that will 
> be sent after Penny's patch serie "[PATCH v2 00/41] xen/arm: Add 
> Armv8-R64 MPU support to Xen - Part#1" is upstreamed.
> My aim is to extract the non-dependent changes and send them for review.
I can review the patch. But I am not willing to merge it as it gives the 
false impression that Xen would boot on Cortex-R52.
In fact, I think this patch should only be merged once we have all the 
MPU merged.
IMHO, patches are independent are rework (e.g. code split...) that would 
help the MPU.
Cheers,

--
Julien Grall