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?
Konrad
