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>

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);
 }

hw/arm/aspeed_ast2600.c

@@ -322,10 +322,10 @@ static void aspeed_soc_ast2600_realize(DeviceState *dev, Error **errp)
         sysbus_connect_irq(SYS_BUS_DEVICE(&s->timerctrl), i, irq);
     }
 
-    /* UART - attach an 8250 to the IO space as our UART5 */
-    serial_mm_init(get_system_memory(), sc->memmap[ASPEED_DEV_UART5], 2,
-                   aspeed_soc_get_irq(s, ASPEED_DEV_UART5),
-                   38400, serial_hd(0), DEVICE_LITTLE_ENDIAN);
+    /* UART - attach an 8250 to the IO space as our UART */
+    serial_mm_init(get_system_memory(), sc->memmap[s->uart_default], 2,
+                   aspeed_soc_get_irq(s, s->uart_default), 38400,
+                   serial_hd(0), DEVICE_LITTLE_ENDIAN);
 
     /* I2C */
     object_property_set_link(OBJECT(&s->i2c), "dram", OBJECT(s->dram_mr),

hw/arm/aspeed_soc.c

@@ -287,9 +287,9 @@ static void aspeed_soc_realize(DeviceState *dev, Error **errp)
         sysbus_connect_irq(SYS_BUS_DEVICE(&s->timerctrl), i, irq);
     }
 
-    /* UART - attach an 8250 to the IO space as our UART5 */
-    serial_mm_init(get_system_memory(), sc->memmap[ASPEED_DEV_UART5], 2,
-                   aspeed_soc_get_irq(s, ASPEED_DEV_UART5), 38400,
+    /* UART - attach an 8250 to the IO space as our UART */
+    serial_mm_init(get_system_memory(), sc->memmap[s->uart_default], 2,
+                   aspeed_soc_get_irq(s, s->uart_default), 38400,
                    serial_hd(0), DEVICE_LITTLE_ENDIAN);
 
     /* I2C */
@@ -439,6 +439,8 @@ static void aspeed_soc_realize(DeviceState *dev, Error **errp)
 static Property aspeed_soc_properties[] = {
     DEFINE_PROP_LINK("dram", AspeedSoCState, dram_mr, TYPE_MEMORY_REGION,
                      MemoryRegion *),
+    DEFINE_PROP_UINT32("uart-default", AspeedSoCState, uart_default,
+                       ASPEED_DEV_UART5),
     DEFINE_PROP_END_OF_LIST(),
 };
 

include/hw/arm/aspeed.h

@@ -38,6 +38,7 @@ struct AspeedMachineClass {
     uint32_t num_cs;
     uint32_t macs_mask;
     void (*i2c_init)(AspeedMachineState *bmc);
+    uint32_t uart_default;
 };
 
 

include/hw/arm/aspeed_soc.h

@@ -65,6 +65,7 @@ struct AspeedSoCState {
     AspeedSDHCIState sdhci;
     AspeedSDHCIState emmc;
     AspeedLPCState lpc;
+    uint32_t uart_default;
 };
 
 #define TYPE_ASPEED_SOC "aspeed-soc"