[13/32] riscv: Fix builtin DTB handling

diff --git a/arch/riscv/Kconfig.socs b/arch/riscv/Kconfig.socs
index e724fddc44ba..97ef393d0ed0 100644
--- a/arch/riscv/Kconfig.socs
+++ b/arch/riscv/Kconfig.socs
@@ -33,9 +33,10 @@  config SOC_KENDRYTE
 	help
 	  This enables support for Kendryte K210 SoC platform hardware.
 
-config SOC_KENDRYTE_K210_DTB
-	def_bool y
-	depends on SOC_KENDRYTE_K210_DTB_BUILTIN
+config BUILTIN_DTB
+	def_bool n
+
+if SOC_KENDRYTE
 
 config SOC_KENDRYTE_K210_DTB_BUILTIN
 	bool "Builtin device tree for the Kendryte K210"
@@ -43,10 +44,21 @@  config SOC_KENDRYTE_K210_DTB_BUILTIN
 	default y
 	select OF
 	select BUILTIN_DTB
-	select SOC_KENDRYTE_K210_DTB
 	help
-	  Builds a device tree for the Kendryte K210 into the Linux image.
+	  Build a device tree for the Kendryte K210 into the Linux image.
 	  This option should be selected if no bootloader is being used.
 	  If unsure, say Y.
 
+config SOC_KENDRYTE_K210_DTB_SOURCE
+	string "Source file for the Kendryte K210 builtin DTB"
+	depends on SOC_KENDRYTE
+	depends on SOC_KENDRYTE_K210_DTB_BUILTIN
+	default "k210"
+	help
+	  Base name (without suffix, relative to arch/riscv/boot/dts/kendryte)
+	  for the DTS file that will be used to produce the DTB linked into the
+	  kernel.
+
+endif
+
 endmenu
diff --git a/arch/riscv/boot/dts/kendryte/Makefile b/arch/riscv/boot/dts/kendryte/Makefile
index 1a88e616f18e..83636693166d 100644
--- a/arch/riscv/boot/dts/kendryte/Makefile
+++ b/arch/riscv/boot/dts/kendryte/Makefile
@@ -1,4 +1,5 @@ 
 # SPDX-License-Identifier: GPL-2.0
-dtb-$(CONFIG_SOC_KENDRYTE_K210_DTB) += k210.dtb
-
+ifneq ($(CONFIG_SOC_KENDRYTE_K210_DTB_SOURCE),"")
+dtb-y += $(strip $(shell echo $(CONFIG_SOC_KENDRYTE_K210_DTB_SOURCE))).dtb
 obj-$(CONFIG_SOC_KENDRYTE_K210_DTB_BUILTIN) += $(addsuffix .o, $(dtb-y))
+endif
diff --git a/arch/riscv/include/asm/soc.h b/arch/riscv/include/asm/soc.h
index 6c8363b1f327..f494066051a2 100644
--- a/arch/riscv/include/asm/soc.h
+++ b/arch/riscv/include/asm/soc.h
@@ -21,42 +21,4 @@  void soc_early_init(void);
 extern unsigned long __soc_early_init_table_start;
 extern unsigned long __soc_early_init_table_end;
 
-/*
- * Allows Linux to provide a device tree, which is necessary for SOCs that
- * don't provide a useful one on their own.
- */
-struct soc_builtin_dtb {
-	unsigned long vendor_id;
-	unsigned long arch_id;
-	unsigned long imp_id;
-	void *(*dtb_func)(void);
-};
-
-/*
- * The argument name must specify a valid DTS file name without the dts
- * extension.
- */
-#define SOC_BUILTIN_DTB_DECLARE(name, vendor, arch, impl)		\
-	extern void *__dtb_##name##_begin;				\
-									\
-	static __init __used						\
-	void *__soc_builtin_dtb_f__##name(void)				\
-	{								\
-		return (void *)&__dtb_##name##_begin;			\
-	}								\
-									\
-	static const struct soc_builtin_dtb __soc_builtin_dtb__##name	\
-		__used __section("__soc_builtin_dtb_table") =		\
-	{								\
-		.vendor_id = vendor,					\
-		.arch_id   = arch,					\
-		.imp_id    = impl,					\
-		.dtb_func  = __soc_builtin_dtb_f__##name,		\
-	}
-
-extern unsigned long __soc_builtin_dtb_table_start;
-extern unsigned long __soc_builtin_dtb_table_end;
-
-void *soc_lookup_builtin_dtb(void);
-
 #endif
diff --git a/arch/riscv/kernel/soc.c b/arch/riscv/kernel/soc.c
index c7b0a73e382e..a0516172a33c 100644
--- a/arch/riscv/kernel/soc.c
+++ b/arch/riscv/kernel/soc.c
@@ -26,30 +26,3 @@  void __init soc_early_init(void)
 		}
 	}
 }
-
-static bool soc_builtin_dtb_match(unsigned long vendor_id,
-				unsigned long arch_id, unsigned long imp_id,
-				const struct soc_builtin_dtb *entry)
-{
-	return entry->vendor_id == vendor_id &&
-	       entry->arch_id == arch_id &&
-	       entry->imp_id == imp_id;
-}
-
-void * __init soc_lookup_builtin_dtb(void)
-{
-	unsigned long vendor_id, arch_id, imp_id;
-	const struct soc_builtin_dtb *s;
-
-	__asm__ ("csrr %0, mvendorid" : "=r"(vendor_id));
-	__asm__ ("csrr %0, marchid" : "=r"(arch_id));
-	__asm__ ("csrr %0, mimpid" : "=r"(imp_id));
-
-	for (s = (void *)&__soc_builtin_dtb_table_start;
-	     (void *)s < (void *)&__soc_builtin_dtb_table_end; s++) {
-		if (soc_builtin_dtb_match(vendor_id, arch_id, imp_id, s))
-			return s->dtb_func();
-	}
-
-	return NULL;
-}
diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index ea933b789a88..d9c8d8819ed8 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -591,11 +591,7 @@  static void __init setup_vm_final(void)
 asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 {
 #ifdef CONFIG_BUILTIN_DTB
-	dtb_early_va = soc_lookup_builtin_dtb();
-	if (!dtb_early_va) {
-		/* Fallback to first available DTS */
-		dtb_early_va = (void *) __dtb_start;
-	}
+	dtb_early_va = (void *) __dtb_start;
 #else
 	dtb_early_va = (void *)dtb_pa;
 #endif
diff --git a/drivers/soc/kendryte/k210-sysctl.c b/drivers/soc/kendryte/k210-sysctl.c
index 707019223dd8..4608fbca20e1 100644
--- a/drivers/soc/kendryte/k210-sysctl.c
+++ b/drivers/soc/kendryte/k210-sysctl.c
@@ -246,15 +246,3 @@  static void __init k210_soc_early_init(const void *fdt)
 	iounmap(regs);
 }
 SOC_EARLY_INIT_DECLARE(generic_k210, "kendryte,k210", k210_soc_early_init);
-
-#ifdef CONFIG_SOC_KENDRYTE_K210_DTB_BUILTIN
-/*
- * Generic entry for the default k210.dtb embedded DTB for boards with:
- *   - Vendor ID: 0x4B5
- *   - Arch ID: 0xE59889E6A5A04149 (= "Canaan AI" in UTF-8 encoded Chinese)
- *   - Impl ID:	0x4D41495832303030 (= "MAIX2000")
- * These values are reported by the SiPEED MAXDUINO, SiPEED MAIX GO and
- * SiPEED Dan dock boards.
- */
-SOC_BUILTIN_DTB_DECLARE(k210, 0x4B5, 0xE59889E6A5A04149, 0x4D41495832303030);
-#endif