[PATCH v4 04/21] hw/arm/ast27x0: Start TSP in powered-off state to match hardware behavior

[Jamin Lin <jamin_lin@aspeedtech.com>]

In the previous design, both the PSP and TSP were started together during
SoC initialization. However, on real hardware, the TSP begins in a powered-off
state. The typical boot sequence involves the PSP powering up first, loading
the TSP firmware binary into shared memory via DRAM remap, and then releasing
the TSP reset and enabling it through SCU control registers.

To more accurately model this behavior in QEMU, this commit sets the
"start-powered-off" property for the TSP's ARMv7M core. This change ensures
the TSP remains off until explicitly enabled via the SCU, simulating the
real-world flow where the PSP controls TSP boot through SCU interaction.

Signed-off-by: Jamin Lin <jamin_lin@aspeedtech.com>
---
 hw/arm/aspeed_ast27x0-tsp.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/arm/aspeed_ast27x0-tsp.c b/hw/arm/aspeed_ast27x0-tsp.c
index 674307103e..b30f2afd62 100644
--- a/hw/arm/aspeed_ast27x0-tsp.c
+++ b/hw/arm/aspeed_ast27x0-tsp.c
@@ -166,6 +166,13 @@ static void aspeed_soc_ast27x0tsp_realize(DeviceState *dev_soc, Error **errp)
     qdev_connect_clock_in(armv7m, "cpuclk", s->sysclk);
     object_property_set_link(OBJECT(&a->armv7m), "memory",
                              OBJECT(s->memory), &error_abort);
+    /*
+     * The TSP starts in a powered-down state and can be powered up
+     * by setting the TSP Control Register through the SCU
+     * (System Control Unit)
+     */
+    object_property_set_bool(OBJECT(&a->armv7m), "start-powered-off", true,
+                             &error_abort);
     sysbus_realize(SYS_BUS_DEVICE(&a->armv7m), &error_abort);
 
     /* SDRAM */
-- 
2.43.0