MIPS: platform: Allow for DTB to be moved during kernel relocation

Add plat_fdt_relocated(void*) API to allow the kernel relocation code to
update platform's information about the DTB location if the DTB had to
be moved due to being placed in a location used by the relocated kernel.

Signed-off-by: Marcin Nowakowski <marcin.nowakowski@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14611/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/generic/init.c

@@ -88,6 +88,19 @@ void __init *plat_get_fdt(void)
 	return (void *)fdt;
 }
 
+void __init plat_fdt_relocated(void *new_location)
+{
+	/*
+	 * reset fdt as the cached value would point to the location
+	 * before relocations happened and update the location argument
+	 * if it was passed using UHI
+	 */
+	fdt = NULL;
+
+	if (fw_arg0 == -2)
+		fw_arg1 = (unsigned long)new_location;
+}
+
 void __init plat_mem_setup(void)
 {
 	if (mach && mach->fixup_fdt)

arch/mips/include/asm/bootinfo.h

@@ -164,6 +164,19 @@ static inline void plat_swiotlb_setup(void) {}
  * Return: Pointer to the flattened device tree blob.
  */
 extern void *plat_get_fdt(void);
+
+#ifdef CONFIG_RELOCATABLE
+
+/**
+ * plat_fdt_relocated() - Update platform's information about relocated dtb
+ *
+ * This function provides a platform-independent API to set platform's
+ * information about relocated DTB if it needs to be moved due to kernel
+ * relocation occurring at boot.
+ */
+void plat_fdt_relocated(void *new_location);
+
+#endif /* CONFIG_RELOCATABLE */
 #endif /* CONFIG_USE_OF */
 
 #endif /* _ASM_BOOTINFO_H */