riscv: qemu: detect and boot the kernel passed by QEMU

QEMU embeds the location of the kernel image in the device tree. Store
this address in the environment as variable kernel_start. It is used in
the board-local distro boot command QEMU to boot the kernel with the
U-Boot device tree. The QEMU boot command is added as the first boot
target device.

Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Alexander Graf <agraf@suse.de>

1 files changed, 29 insertions, 0 deletions

diff --git a/board/emulation/qemu-riscv/qemu-riscv.c b/board/emulation/qemu-riscv/qemu-riscv.c
index 2ce093e19a9..587f2c49094 100644
--- a/board/emulation/qemu-riscv/qemu-riscv.c
+++ b/board/emulation/qemu-riscv/qemu-riscv.c
@@ -19,3 +19,32 @@ int board_init(void)
 
 	return 0;
 }
+
+int board_late_init(void)
+{
+	ulong kernel_start;
+	ofnode chosen_node;
+	int ret;
+
+	chosen_node = ofnode_path("/chosen");
+	if (!ofnode_valid(chosen_node)) {
+		debug("No chosen node found, can't get kernel start address\n");
+		return 0;
+	}
+
+#ifdef CONFIG_ARCH_RV64I
+	ret = ofnode_read_u64(chosen_node, "riscv,kernel-start",
+			      (u64 *)&kernel_start);
+#else
+	ret = ofnode_read_u32(chosen_node, "riscv,kernel-start",
+			      (u32 *)&kernel_start);
+#endif
+	if (ret) {
+		debug("Can't find kernel start address in device tree\n");
+		return 0;
+	}
+
+	env_set_hex("kernel_start", kernel_start);
+
+	return 0;
+}