sh: add support for linking a builtin device tree blob in the kernel

Signed-off-by: Rich Felker <dalias@libc.org>

5 files changed, 41 insertions, 3 deletions

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 0d5f3a9bb315..ceeda5c1a70a 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -739,6 +739,26 @@ endmenu
 
 menu "Boot options"
 
+config USE_BUILTIN_DTB
+        bool "Use builtin DTB"
+        default n
+        depends on SH_DEVICE_TREE
+        help
+          Link a device tree blob for particular hardware into the kernel,
+          suppressing use of the DTB pointer provided by the bootloader.
+          This option should only be used with legacy bootloaders that are
+          not capable of providing a DTB to the kernel, or for experimental
+          hardware without stable device tree bindings.
+
+config BUILTIN_DTB_SOURCE
+        string "Source file for builtin DTB"
+        default ""
+        depends on USE_BUILTIN_DTB
+        help
+          Base name (without suffix, relative to arch/sh/boot/dts) for the
+          a DTS file that will be used to produce the DTB linked into the
+          kernel.
+
 config ZERO_PAGE_OFFSET
         hex
         default "0x00010000" if PAGE_SIZE_64KB || SH_RTS7751R2D || \
diff --git a/arch/sh/Makefile b/arch/sh/Makefile
index bf5b3f5f4962..3b2c8b4827d0 100644
--- a/arch/sh/Makefile
+++ b/arch/sh/Makefile
@@ -130,6 +130,8 @@ head-y	:= arch/sh/kernel/head_$(BITS).o
 core-y                          += arch/sh/kernel/ arch/sh/mm/ arch/sh/boards/
 core-$(CONFIG_SH_FPU_EMU)       += arch/sh/math-emu/
 
+core-$(CONFIG_USE_BUILTIN_DTB)  += arch/sh/boot/dts/
+
 # Mach groups
 machdir-$(CONFIG_SOLUTION_ENGINE)               += mach-se
 machdir-$(CONFIG_SH_HP6XX)                      += mach-hp6xx
diff --git a/arch/sh/boards/of-generic.c b/arch/sh/boards/of-generic.c
index 911ffb9f115b..1fb6d5714bae 100644
--- a/arch/sh/boards/of-generic.c
+++ b/arch/sh/boards/of-generic.c
@@ -124,13 +124,22 @@ static void __init sh_of_time_init(void)
 
 static void __init sh_of_setup(char **cmdline_p)
 {
+        struct device_node *root;
+
+#ifdef CONFIG_USE_BUILTIN_DTB
+        unflatten_and_copy_device_tree();
+#else
         unflatten_device_tree();
+#endif
 
         board_time_init = sh_of_time_init;
 
-        sh_mv.mv_name = of_flat_dt_get_machine_name();
-        if (!sh_mv.mv_name)
-                sh_mv.mv_name = "Unknown SH model";
+        sh_mv.mv_name = "Unknown SH model";
+        root = of_find_node_by_path("/");
+        if (root) {
+                of_property_read_string(root, "model", &sh_mv.mv_name);
+                of_node_put(root);
+        }
 
         sh_of_smp_probe();
 }
diff --git a/arch/sh/boot/dts/Makefile b/arch/sh/boot/dts/Makefile
new file mode 100644
index 000000000000..e5ce3a0de7f4
--- /dev/null
+++ b/arch/sh/boot/dts/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_USE_BUILTIN_DTB) += $(patsubst "%",%,$(CONFIG_BUILTIN_DTB_SOURCE)).dtb.o
+
+clean-files := *.dtb.S
diff --git a/arch/sh/kernel/setup.c b/arch/sh/kernel/setup.c
index 5d34605b58b5..5b9eb70311e3 100644
--- a/arch/sh/kernel/setup.c
+++ b/arch/sh/kernel/setup.c
@@ -251,7 +251,11 @@ void __ref sh_fdt_init(phys_addr_t dt_phys)
         /* Avoid calling an __init function on secondary cpus. */
         if (done) return;
 
+#ifdef CONFIG_USE_BUILTIN_DTB
+        dt_virt = __dtb_start;
+#else
         dt_virt = phys_to_virt(dt_phys);
+#endif
 
         if (!dt_virt || !early_init_dt_scan(dt_virt)) {
                 pr_crit("Error: invalid device tree blob"