[PATCH v1 6/6] xen/riscv: relocating and unflattening host device tree

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Relocate FDT to Xen heap instead of using early mapping as it is
expected that discard_initial_modules() ( is supposed to call in
the future ) discards the FDT boot module and remove_early_mappings()
destroys the early mapping.

Unflatten a device tree, creating the tree of struct device_node.
It also fills the "name" and "type" pointers of the nodes so the normal
device-tree walking functions can be used.

Set device_tree_flattened to NULL in the case when acpi_disabled is
equal to false.

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
 xen/arch/riscv/setup.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/xen/arch/riscv/setup.c b/xen/arch/riscv/setup.c
index ff667260ec..41826f77fb 100644
--- a/xen/arch/riscv/setup.c
+++ b/xen/arch/riscv/setup.c
@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <xen/acpi.h>
 #include <xen/bug.h>
 #include <xen/bootfdt.h>
 #include <xen/compile.h>
@@ -71,6 +72,7 @@ void __init noreturn start_xen(unsigned long bootcpu_id,
                                paddr_t dtb_addr)
 {
     const char *cmdline;
+    size_t fdt_size;
 
     remove_identity_mapping();
 
@@ -95,7 +97,7 @@ void __init noreturn start_xen(unsigned long bootcpu_id,
                           _end - _start, false) )
         panic("Failed to add BOOTMOD_XEN\n");
 
-    if ( !boot_fdt_info(device_tree_flattened, dtb_addr) )
+    if ( !(fdt_size = boot_fdt_info(device_tree_flattened, dtb_addr)) )
         BUG();
 
     cmdline = boot_fdt_cmdline(device_tree_flattened);
@@ -114,6 +116,18 @@ void __init noreturn start_xen(unsigned long bootcpu_id,
      */
     system_state = SYS_STATE_boot;
 
+    if ( acpi_disabled )
+    {
+        printk("Booting using Device Tree\n");
+        device_tree_flattened = relocate_fdt(dtb_addr, fdt_size);
+        dt_unflatten_host_device_tree();
+    }
+    else
+    {
+        device_tree_flattened = NULL;
+        panic("Booting using ACPI isn't supported\n");
+    }
+
     printk("All set up\n");
 
     machine_halt();
-- 
2.47.0