diff mbox series

[v2,1/3] hw/arm/virt: Add serial aliases in DTB

Message ID 20240610162343.2131524-2-peter.maydell@linaro.org
State New
Headers show
Series hw/arm: Create second NonSecure UART for virt board | expand

Commit Message

Peter Maydell June 10, 2024, 4:23 p.m. UTC 
If there is more than one UART in the DTB, then there is no guarantee
on which order a guest is supposed to initialise them.  The standard
solution to this is "serialN" entries in the "/aliases" node of the
dtb which give the nodename of the UARTs.

At the moment we only have two UARTs in the DTB when one is for
the Secure world and one for the Non-Secure world, so this isn't
really a problem. However if we want to add a second NS UART we'll
need the aliases to ensure guests pick the right one.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 hw/arm/virt.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 3c93c0c0a61..0c1dab67c00 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -284,6 +284,8 @@  static void create_fdt(VirtMachineState *vms)
         }
     }
 
+    qemu_fdt_add_subnode(fdt, "/aliases");
+
     /* Clock node, for the benefit of the UART. The kernel device tree
      * binding documentation claims the PL011 node clock properties are
      * optional but in practice if you omit them the kernel refuses to
@@ -939,7 +941,9 @@  static void create_uart(const VirtMachineState *vms, int uart,
 
     if (uart == VIRT_UART) {
         qemu_fdt_setprop_string(ms->fdt, "/chosen", "stdout-path", nodename);
+        qemu_fdt_setprop_string(ms->fdt, "/aliases", "serial0", nodename);
     } else {
+        qemu_fdt_setprop_string(ms->fdt, "/aliases", "serial1", nodename);
         /* Mark as not usable by the normal world */
         qemu_fdt_setprop_string(ms->fdt, nodename, "status", "disabled");
         qemu_fdt_setprop_string(ms->fdt, nodename, "secure-status", "okay");