hw/arm/aspeed: Allow machine to set UART default

When you run QEMU with an Aspeed machine and a single serial device
using stdio like this:

    qemu -machine ast2600-evb -drive ... -serial stdio

The guest OS can read and write to the UART5 registers at 0x1E784000 and
it will receive from stdin and write to stdout. The Aspeed SoC's have a
lot more UART's though (AST2500 has 5, AST2600 has 13) and depending on
the board design, may be using any of them as the serial console. (See
"stdout-path" in a DTS to check which one is chosen).

Most boards, including all of those currently defined in
hw/arm/aspeed.c, just use UART5, but some use UART1. This change adds
some flexibility for different boards without requiring users to change
their command-line invocation of QEMU.

I tested this doesn't break existing code by booting an AST2500 OpenBMC
image and an AST2600 OpenBMC image, each using UART5 as the console.

Then I tested switching the default to UART1 and booting an AST2600
OpenBMC image that uses UART1, and that worked too.

Signed-off-by: Peter Delevoryas <pdel@fb.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20210901153615.2746885-2-pdel@fb.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/hw/arm/aspeed.c b/hw/arm/aspeed.c
index 886e599..7a94593 100644
--- a/hw/arm/aspeed.c
+++ b/hw/arm/aspeed.c
@@ -350,6 +350,8 @@ static void aspeed_machine_init(MachineState *machine)
         object_property_set_int(OBJECT(&bmc->soc), "hw-prot-key",
                                 ASPEED_SCU_PROT_KEY, &error_abort);
     }
+    qdev_prop_set_uint32(DEVICE(&bmc->soc), "uart-default",
+                         amc->uart_default);
     qdev_realize(DEVICE(&bmc->soc), NULL, &error_abort);
 
     memory_region_add_subregion(get_system_memory(),
@@ -848,6 +850,7 @@ static void aspeed_machine_class_init(ObjectClass *oc, void *data)
     mc->no_parallel = 1;
     mc->default_ram_id = "ram";
     amc->macs_mask = ASPEED_MAC0_ON;
+    amc->uart_default = ASPEED_DEV_UART5;
 
     aspeed_machine_class_props_init(oc);
 }