risc-v/k230: add NUTTSBI based kernel build support

Previously k230 kernel build needs OpenSBI wrapping for use on
target, thus leading to larger program and memory overheads.
This patch adds alternative small overhead kernel build support.

Changes:

- in arch/risc-v/src/k230:
  - k230_head.S          entrance renamed for sake of NUTTSBI
  - k230_irq.c           add M-mode handling for NUTTSBI case
  - k230_mm_init.c       add L3 table for smaller RAM case
  - hardware/k230_plic.h add PLIC_CTRL definition
  - Make.defs            use CHIP_ASRCS to fix entrance selection
- in boards/risc-v/canmv230/scripts:
  - Make.defs            add support for NUTTSBI case

Additions:

- in boards/riscv/canmv230/:
  - scripts/ld-nuttsbi.script  link script for NUTTSBI case
  - configs/nsbi/defconfig     config for NUTTSBI case

The artifact nuttx.bin from this configuration can be used directly
on target as OpenSBI wrapping is not needed.

Signed-off-by: Yanfeng Liu <yfliu2008@qq.com>

fix typo

boards/risc-v/k230/canmv230/scripts/Make.defs

@@ -24,7 +24,11 @@ include $(TOPDIR)/arch/risc-v/src/common/Toolchain.defs
 
 ifeq ($(CONFIG_ARCH_CHIP_K230),y)
 ifeq ($(CONFIG_BUILD_KERNEL),y)
+ifeq ($(CONFIG_NUTTSBI),y)
+  LDSCRIPT = ld-nuttsbi.script
+else
   LDSCRIPT = ld-kernel.script
+endif
 else ifeq ($(CONFIG_BUILD_PROTECTED),y)
   LDSCRIPT = ld-protected.script
 else
@@ -54,17 +58,21 @@ endif
 
 # POSTBUILD management
 
-# KERNEL build needs real ROMFS and SBI wrapping
+# KERNEL builds need real ROMFS and even OpenSBI wrapping
 
 ifeq ($(CONFIG_BUILD_KERNEL),y)
 ifeq ($(wildcard $(BOARD_DIR)$(DELIM)src$(DELIM)romfs_boot.c),)
 define POSTBUILD
-  $(Q) echo "Please replace stub ROMFS w/ real one."
+  $(Q) echo "Please replace stub ROMFS with real one."
   $(Q) rm $(BOARD_DIR)$(DELIM)src$(DELIM)libboard.a
 endef
+else ifneq ($(CONFIG_NUTTSBI),y)
+define POSTBUILD
+  $(Q) echo "Please wrap nuttx.bin with OpenSBI to run on target."
+endef
 else
 define POSTBUILD
-  $(Q) echo "wrap nuttx.bin w/ SBI to run on target."
+  $(Q) echo "Please try nuttx.bin on target."
 endef
 endif
 endif

boards/risc-v/k230/canmv230/scripts/ld-nuttsbi.script

@@ -0,0 +1,143 @@
+/****************************************************************************
+ * boards/risc-v/k230/canmv230/scripts/ld-nuttsbi.script
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.  The
+ * ASF licenses this file to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the
+ * License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ ****************************************************************************/
+
+MEMORY
+{
+    kflash (rx) : ORIGIN = 0x8000000, LENGTH = 384K   /* w/ cache */
+    ksram (rwx) : ORIGIN = 0x8080000, LENGTH = 128K   /* w/ cache */
+    pgram (rwx) : ORIGIN = 0x8600000, LENGTH =  10M   /* w/ cache */
+}
+
+OUTPUT_ARCH("riscv")
+
+/* Provide the kernel boundaries */
+
+__kflash_start = ORIGIN(kflash);
+__kflash_size = LENGTH(kflash);
+__ksram_start = ORIGIN(ksram);
+__ksram_size = LENGTH(ksram);
+__ksram_end = ORIGIN(ksram) + LENGTH(ksram);
+
+/* Page heap */
+
+__pgheap_start = ORIGIN(pgram);
+__pgheap_size = LENGTH(pgram);
+
+SECTIONS
+{
+  . = 0x8000000;
+
+  .text :
+    {
+      _stext = . ;
+      *(.text)
+      *(.text.*)
+      *(.gnu.warning)
+      *(.stub)
+      *(.glue_7)
+      *(.glue_7t)
+      *(.jcr)
+
+      /* C++ support:  The .init and .fini sections contain specific logic
+       * to manage static constructors and destructors.
+       */
+
+      *(.gnu.linkonce.t.*)
+      *(.init)             /* Old ABI */
+      *(.fini)             /* Old ABI */
+      _etext = . ;
+    }
+
+  .rodata :
+    {
+      _srodata = . ;
+      *(.rodata)
+      *(.rodata1)
+      *(.rodata.*)
+      *(.gnu.linkonce.r*)
+      _erodata = . ;
+    }
+
+  .tdata : {
+      _stdata = ABSOLUTE(.);
+      *(.tdata .tdata.* .gnu.linkonce.td.*);
+      _etdata = ABSOLUTE(.);
+  }
+
+  .tbss : {
+      _stbss = ABSOLUTE(.);
+      *(.tbss .tbss.* .gnu.linkonce.tb.* .tcommon);
+      _etbss = ABSOLUTE(.);
+  }
+
+  _eronly = ABSOLUTE(.);
+
+  .data :
+    {
+      _sdata = . ;
+      *(.data)
+      *(.data1)
+      *(.data.*)
+      *(.gnu.linkonce.d*)
+      . = ALIGN(4);
+      _edata = . ;
+    }
+
+  .bss :
+    {
+      _sbss = . ;
+      *(.bss)
+      *(.bss.*)
+      *(.sbss)
+      *(.sbss.*)
+      *(.gnu.linkonce.b*)
+      *(COMMON)
+      _ebss = . ;
+    } > ksram
+
+    /* Page tables here, align to 4K boundary */
+
+    .pgtables (NOLOAD) : ALIGN(0x1000) {
+        *(.pgtables)
+        . = ALIGN(4);
+    } > ksram
+
+    /* Stack top */
+
+    .stack_top : {
+        . = ALIGN(32);
+        _ebss = ABSOLUTE(.);
+    } > ksram
+
+    /* Stabs debugging sections. */
+
+    .stab 0 : { *(.stab) }
+    .stabstr 0 : { *(.stabstr) }
+    .stab.excl 0 : { *(.stab.excl) }
+    .stab.exclstr 0 : { *(.stab.exclstr) }
+    .stab.index 0 : { *(.stab.index) }
+    .stab.indexstr 0 : { *(.stab.indexstr) }
+    .comment 0 : { *(.comment) }
+    .debug_abbrev 0 : { *(.debug_abbrev) }
+    .debug_info 0 : { *(.debug_info) }
+    .debug_line 0 : { *(.debug_line) }
+    .debug_pubnames 0 : { *(.debug_pubnames) }
+    .debug_aranges 0 : { *(.debug_aranges) }
+}