Re: [SPAM] [PATCH v1 05/12] hw/arm/ast27x0: Share single SCU instance across PSP, SSP, and TSP

["Cédric Le Goater" <clg@kaod.org>]

On 10/15/25 08:22, Jamin Lin wrote:
> AST2700 has a single SCU hardware block, memory-mapped at
> 0x12C02000–0x12C03FFF from the perspective of the main CA35 processor (PSP).
> The SSP and TSP coprocessors access this same SCU block at different
> addresses: 0x72C02000–0x72C03FFF.
> 
> Previously, each subsystem (PSP, SSP, and TSP) instantiated its own SCU
> device, resulting in three independent SCU instances in the QEMU model.
> In real hardware, however, only a single SCU exists and is shared among
> all processors.
> 
> This commit reworks the SCU model to correctly reflect the hardware
> behavior by allowing SSP and TSP to reference the PSP’s SCU instance.
> The following changes are introduced:
> 
> - Add a scu property to AspeedCoprocessorState for linking the
>    coprocessor to the PSP’s SCU instance.
> - Replace per-coprocessor SCU instantiation with a shared SCU link.
> - Add "MemoryRegion scu_alias" to model address remapping for SSP and TSP.
> - Create SCU alias regions in both SSP and TSP coprocessors and map
>    them at 0x72C02000 to mirror the PSP’s SCU registers.
> - Ensure the SCU device in PSP is realized before SSP/TSP alias setup.
> 
> With this change, PSP, SSP, and TSP now share a consistent SCU state,
> matching the single-SCU hardware design of AST2700.
> 
> Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
> ---
>   include/hw/arm/aspeed_coprocessor.h |  4 ++--
>   hw/arm/aspeed_ast27x0-fc.c          |  4 ++++
>   hw/arm/aspeed_ast27x0-ssp.c         | 13 +++++--------
>   hw/arm/aspeed_ast27x0-tsp.c         | 13 +++++--------
>   hw/arm/aspeed_coprocessor_common.c  |  2 ++
>   5 files changed, 18 insertions(+), 18 deletions(-)
> 


Reviewed-by: Cédric Le Goater <clg@redhat.com>

Thanks,

C.