AST2700 has a 128KB SRAM, physically mapped at 0x10000000–0x1001FFFF for the PSP (CA35) processor. The SSP coprocessor shares this same SRAM but accesses it through a different address window at 0x70000000–0x7001FFFF.
To model this shared-memory behavior in QEMU, this commit introduces a linked SRAM property and alias mapping between the PSP and SSP subsystems. Changes include: - Add a "MemoryRegion *sram" link and "MemoryRegion sram_alias" to AspeedCoprocessorState. - Register the new "sram" property in aspeed_coprocessor_common.c. - In aspeed_ast27x0-fc.c, connect the SSP coprocessor’s "sram" link to the PSP’s SRAM region. - In aspeed_ast27x0-ssp.c, create an alias mapping for SRAM at 0x70000000 – 0x7001FFFF in the SSP’s memory map. This ensures that the SSP can correctly access the shared SRAM contents through its own address space while maintaining a consistent physical backing region. It also guarantees that the SRAM is realized before the SSP device, ensuring successful alias setup. Signed-off-by: Jamin Lin <[email protected]> --- include/hw/arm/aspeed_coprocessor.h | 3 ++- hw/arm/aspeed_ast27x0-fc.c | 4 ++++ hw/arm/aspeed_ast27x0-ssp.c | 7 +++++++ hw/arm/aspeed_coprocessor_common.c | 2 ++ 4 files changed, 15 insertions(+), 1 deletion(-) diff --git a/include/hw/arm/aspeed_coprocessor.h b/include/hw/arm/aspeed_coprocessor.h index 0c7168a89c..d9a5f517d7 100644 --- a/include/hw/arm/aspeed_coprocessor.h +++ b/include/hw/arm/aspeed_coprocessor.h @@ -17,7 +17,8 @@ struct AspeedCoprocessorState { MemoryRegion *memory; MemoryRegion sdram; - MemoryRegion sram; + MemoryRegion *sram; + MemoryRegion sram_alias; Clock *sysclk; AspeedSCUState scu; diff --git a/hw/arm/aspeed_ast27x0-fc.c b/hw/arm/aspeed_ast27x0-fc.c index a61ecff390..25e668a648 100644 --- a/hw/arm/aspeed_ast27x0-fc.c +++ b/hw/arm/aspeed_ast27x0-fc.c @@ -118,6 +118,8 @@ static bool ast2700fc_ssp_init(MachineState *machine, Error **errp) AspeedCoprocessorState *soc; AspeedCoprocessorClass *sc; Ast2700FCState *s = AST2700A1FC(machine); + AspeedSoCState *psp = ASPEED_SOC(&s->ca35); + s->ssp_sysclk = clock_new(OBJECT(s), "SSP_SYSCLK"); clock_set_hz(s->ssp_sysclk, 200000000ULL); @@ -134,6 +136,8 @@ static bool ast2700fc_ssp_init(MachineState *machine, Error **errp) sc = ASPEED_COPROCESSOR_GET_CLASS(soc); aspeed_soc_uart_set_chr(soc->uart, ASPEED_DEV_UART4, sc->uarts_base, sc->uarts_num, serial_hd(1)); + object_property_set_link(OBJECT(&s->ssp), "sram", + OBJECT(&psp->sram), &error_abort); if (!qdev_realize(DEVICE(&s->ssp), NULL, errp)) { return false; } diff --git a/hw/arm/aspeed_ast27x0-ssp.c b/hw/arm/aspeed_ast27x0-ssp.c index 9f3a1933a0..66c4ef6d1b 100644 --- a/hw/arm/aspeed_ast27x0-ssp.c +++ b/hw/arm/aspeed_ast27x0-ssp.c @@ -20,6 +20,7 @@ static const hwaddr aspeed_soc_ast27x0ssp_memmap[] = { [ASPEED_DEV_SDRAM] = 0x00000000, + [ASPEED_DEV_SRAM] = 0x70000000, [ASPEED_DEV_INTC] = 0x72100000, [ASPEED_DEV_SCU] = 0x72C02000, [ASPEED_DEV_SCUIO] = 0x74C02000, @@ -195,6 +196,12 @@ static void aspeed_soc_ast27x0ssp_realize(DeviceState *dev_soc, Error **errp) sc->memmap[ASPEED_DEV_SDRAM], &s->sdram); + /* SRAM */ + memory_region_init_alias(&s->sram_alias, OBJECT(s), "sram.alias", + s->sram, 0, memory_region_size(s->sram)); + memory_region_add_subregion(s->memory, sc->memmap[ASPEED_DEV_SRAM], + &s->sram_alias); + /* SCU */ if (!sysbus_realize(SYS_BUS_DEVICE(&s->scu), errp)) { return; diff --git a/hw/arm/aspeed_coprocessor_common.c b/hw/arm/aspeed_coprocessor_common.c index 8a94b44f07..8322ad5eb5 100644 --- a/hw/arm/aspeed_coprocessor_common.c +++ b/hw/arm/aspeed_coprocessor_common.c @@ -25,6 +25,8 @@ static void aspeed_coprocessor_realize(DeviceState *dev, Error **errp) static const Property aspeed_coprocessor_properties[] = { DEFINE_PROP_LINK("memory", AspeedCoprocessorState, memory, TYPE_MEMORY_REGION, MemoryRegion *), + DEFINE_PROP_LINK("sram", AspeedCoprocessorState, sram, TYPE_MEMORY_REGION, + MemoryRegion *), }; static void aspeed_coprocessor_class_init(ObjectClass *oc, const void *data) -- 2.43.0
