On Fri, Sep 15, 2023 at 03:52:36PM +0200, Konrad Dybcio wrote:
> On 14.09.2023 16:09, Stephan Gerhold wrote:
> > On Wed, Sep 13, 2023 at 09:39:50PM +0200, Konrad Dybcio wrote:
> >> On 13.09.2023 12:14, Stephan Gerhold wrote:
> >>> On Wed, Sep 13, 2023 at 10:12:12AM +0100, Bryan O'Donoghue wrote:
> >>>> On 13/09/2023 10:06, Konrad Dybcio wrote:
> >>>>> On 11.09.2023 19:41, Stephan Gerhold wrote:
> >>>>>> Most of the reserved firmware memory on MSM8916 can be relocated when
> >>>>>> respecting the required alignment. To avoid having to precompute the
> >>>>>> reserved memory regions in every board DT, describe the actual
> >>>>>> requirements (size, alignment, alloc-ranges) using the dynamic reserved
> >>>>>> memory allocation.
> >>>>>>
> >>>>>> This approach has several advantages:
> >>>>>>
> >>>>>> 1. We can define "templates" for the reserved memory regions in
> >>>>>> msm8916.dtsi and keep only device-specific details in the board DT.
> >>>>>> This is useful for the "mpss" region size for example, which varies
> >>>>>> from device to device. It is no longer necessary to redefine all
> >>>>>> firmware regions to shift their addresses.
> >>>>>>
> >>>>>> 2. When some of the functionality (e.g. WCNSS, Modem, Venus) is not
> >>>>>> enabled or needed for a device, the reserved memory can stay
> >>>>>> disabled, freeing up the unused reservation for Linux.
> >>>>>>
> >>>>>> 3. Devices with special requirements for one of the firmware regions
> >>>>>> are handled automatically. For example, msm8916-longcheer-l8150
> >>>>>> has non-relocatable "wcnss" firmware that must be loaded exactly
> >>>>>> at address 0x8b600000. When this is defined as a static region,
> >>>>>> the other dynamic allocations automatically adjust to a different
> >>>>>> place with suitable alignment.
> >>>>>>
> >>>>>> All in all this approach significantly reduces the boilerplate necessary
> >>>>>> to define the different firmware regions, and makes it easier to enable
> >>>>>> functionality on the different devices.
> >>>>>>
> >>>>>> Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx>
> >>>>>> ---
> >>>>> [...]
> >>>>>
> >>>>>> mpss_mem: mpss@86800000 {
> >>>>>> + /*
> >>>>>> + * The memory region for the mpss firmware is generally
> >>>>>> + * relocatable and could be allocated dynamically.
> >>>>>> + * However, many firmware versions tend to fail when
> >>>>>> + * loaded to some special addresses, so it is hard to
> >>>>>> + * define reliable alloc-ranges.
> >>>>>> + *
> >>>>>> + * alignment = <0x0 0x400000>;
> >>>>>> + * alloc-ranges = <0x0 0x86800000 0x0 0x8000000>;
> >>>>>> + */
> >>>>> Do we know of any devices that this would actually work on?
> >> [...]
> >>> - On DB410c it works just fine. All addresses I tried work without any
> >>> problems.
> >>>
> >>> - On longcheer-l8150 the modem firmare works fine when the memory
> >>> region starts somewhere between 0x86800000 and 0x8a800000. It also
> >>> works again after 0x8e800000. But on anything between 0x8a800000 and
> >>> 0x8e800000 it's broken for who knows what reason.
> >>> [...]
> >> Were you able to find a phone (likely a very reference-design-based
> >> one) that this worked on, btw?
> >
> > Actually I would count the Longcheer devices (l8150 = Wileyfox Swift and
> > l8910 = BQ Aquaris X5) to the category of close-to-QRD-based devices.
> > Based on quick tests both behave like described above (only
> > 0x8a800000-0x8e800000 is broken). Same for wingtech-wt88047.
> >
> > In other words, for those using the dynamic allocation would work fine,
> > because the alloc-ranges = <0x0 0x86800000 0x0 0x8000000>; only includes
> > working start addresses from 0x86800000 to ~0x89800000 (with a size of
> > 0x5000000).
> >
> > I guess I could use it for them and only make other devices use a fixed
> > address. But I also don't quite have the capacity to test every device
> > to see if relocating the region works or not.
> >
> > I think it's still easiest to allocate mpss on a fixed address
> > everywhere. The only real disadvantage is that overriding "reg", e.g.
> >
> > &mpss_mem {
> > reg = <0x0 0x86800000 0x0 0x5100000>;
> > };
> >
> > is a bit more ugly than overriding size:
> >
> > &mpss_mem {
> > size = <0x0 0x5100000>;
> > };
> >
> > but well, this is a very minor disadvantage.
> So in other words, this only *really* works on apq8016?
>
Hm no? As I wrote, with alloc-ranges = <0x0 0x86800000 0x0 0x8000000> it
also works on the close-to-QRD MSM8916 devices. There are some addresses
that don't work but those might also exist on APQ8016. I haven't tested
placing the firmware all over RAM on all sorts of obscure addresses (and
there is probably little advantage doing so).
With the limited alloc-ranges it would likely work on all devices that
are close to the reference design/firmware from Qualcomm.
Thanks,
Stephan
