riscv: qemu: clear kernel-start/-end in device tree as workaround for BBL

QEMU specifies the location of Linux (supplied with the -kernel
argument) in the device tree using the riscv,kernel-start and
riscv,kernel-end properties. We currently rely on the SBI implementation
of BBL to run Linux and therefore embed Linux as payload in BBL. This
causes an issue, because BBL detects the kernel properties in the device
tree and ignores the Linux payload as a result.
Work around this issue by clearing the kernel properties in the device
tree before booting Linux.

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

diff --git a/board/emulation/qemu-riscv/Kconfig b/board/emulation/qemu-riscv/Kconfig
index be5839b7dbaea6f4f4db7594ed536d44db3e9d38..33ca253432a74328e5997c6f11843d30fc90afbf 100644 (file)
--- a/board/emulation/qemu-riscv/Kconfig
+++ b/board/emulation/qemu-riscv/Kconfig
@@ -30,5 +30,6 @@ config BOARD_SPECIFIC_OPTIONS # dummy
        imply CMD_EXT4
        imply CMD_FAT
        imply BOARD_LATE_INIT
+       imply OF_BOARD_SETUP
 
 endif

diff --git a/board/emulation/qemu-riscv/qemu-riscv.c b/board/emulation/qemu-riscv/qemu-riscv.c
index 587f2c49094dd0814aade5608a23692974cace5f..d6167aaef153ddee8fbba9af19f277b49ac20cf1 100644 (file)
--- a/board/emulation/qemu-riscv/qemu-riscv.c
+++ b/board/emulation/qemu-riscv/qemu-riscv.c
@@ -48,3 +48,42 @@ int board_late_init(void)
 
        return 0;
 }
+
+/*
+ * QEMU specifies the location of Linux (supplied with the -kernel argument)
+ * in the device tree using the riscv,kernel-start and riscv,kernel-end
+ * properties. We currently rely on the SBI implementation of BBL to run
+ * Linux and therefore embed Linux as payload in BBL. This causes an issue,
+ * because BBL detects the kernel properties in the device tree and ignores
+ * the Linux payload as a result. To work around this issue, we clear the
+ * kernel properties before booting Linux.
+ *
+ * This workaround can be removed, once we do not require BBL for its SBI
+ * implementation anymore.
+ */
+int ft_board_setup(void *blob, bd_t *bd)
+{
+       int chosen_offset, ret;
+
+       chosen_offset = fdt_path_offset(blob, "/chosen");
+       if (chosen_offset < 0)
+               return 0;
+
+#ifdef CONFIG_ARCH_RV64I
+       ret = fdt_setprop_u64(blob, chosen_offset, "riscv,kernel-start", 0);
+#else
+       ret = fdt_setprop_u32(blob, chosen_offset, "riscv,kernel-start", 0);
+#endif
+       if (ret)
+               return ret;
+
+#ifdef CONFIG_ARCH_RV64I
+       ret = fdt_setprop_u64(blob, chosen_offset, "riscv,kernel-end", 0);
+#else
+       ret = fdt_setprop_u32(blob, chosen_offset, "riscv,kernel-end", 0);
+#endif
+       if (ret)
+               return ret;
+
+       return 0;
+}