[PATCH v2 1/1] bsp/riscv: Work area size based on /memory node in fdt

[Daniel Cederman]

Uses the first entry in the /memory node to determine the end of the
work area. Falls back on linker symbol if unable to parse the node.
---
 bsps/riscv/shared/start/bspgetworkarea.c | 144 +++++++++++++++++++++++
 spec/build/bsps/riscv/riscv/obj.yml      |   1 +
 2 files changed, 145 insertions(+)
 create mode 100644 bsps/riscv/shared/start/bspgetworkarea.c

diff --git a/bsps/riscv/shared/start/bspgetworkarea.c b/bsps/riscv/shared/start/bspgetworkarea.c
new file mode 100644
index 0000000000..1fa051d25e
--- /dev/null
+++ b/bsps/riscv/shared/start/bspgetworkarea.c
@@ -0,0 +1,144 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+
+/**
+ * @file
+ *
+ * @brief BSP specific initialization support routines
+ *
+ */
+
+/*
+ * COPYRIGHT (c) 1989-2020.
+ * On-Line Applications Research Corporation (OAR).
+ * Cobham Gaisler AB.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <bsp.h>
+#include <bsp/fdt.h>
+
+#include <rtems/sysinit.h>
+
+#include <libfdt.h>
+
+/*
+ *  These are provided by the linkcmds for ALL of the BSPs which use this file.
+ */
+extern char WorkAreaBase[];
+extern char RamEnd[];
+
+static Memory_Area _Memory_Areas[ 1 ];
+
+static const char memory_path[] = "/memory";
+
+static void* get_end_of_memory_from_fdt(void)
+{
+  const void *fdt;
+  const void *val;
+  int node;
+  int parent;
+  int ac;
+  int sc;
+  int len;
+  uintptr_t start;
+  uintptr_t size;
+
+  fdt = bsp_fdt_get();
+
+  node = fdt_path_offset_namelen(
+    fdt,
+    memory_path,
+    (int) sizeof(memory_path) - 1
+  );
+
+  if (node < 0) {
+    return NULL;
+  }
+
+  parent = fdt_parent_offset(fdt, node);
+  if (parent < 0) {
+    return NULL;
+  }
+
+  ac = fdt_address_cells(fdt, parent);
+  if (ac != 1 && ac != 2) {
+    return NULL;
+  }
+
+  sc = fdt_size_cells(fdt, parent);
+  if (sc != 1 && sc != 2) {
+    return NULL;
+  }
+
+  if (sc > ac) {
+    return NULL;
+  }
+
+  val = fdt_getprop(fdt, node, "reg", &len);
+  if (len < sc + ac) {
+    return NULL;
+  }
+
+  if (ac == 1) {
+    start = fdt32_to_cpu(((fdt32_t *)val)[0]);
+    size = fdt32_to_cpu(((fdt32_t *)val)[1]);
+  }
+
+  if (ac == 2) {
+    start = fdt64_to_cpu(((fdt64_t *)val)[0]);
+
+    if (sc == 1)
+      size = fdt32_to_cpu(((fdt32_t *)(val+8))[0]);
+    else
+      size = fdt64_to_cpu(((fdt64_t *)val)[1]);
+  }
+
+  return (void*) (start + size);
+}
+
+static void bsp_memory_initialize( void )
+{
+  void *end;
+
+  /* get end of memory from the "/memory" node in the fdt */
+  end = get_end_of_memory_from_fdt();
+  if (end == 0) {
+    /* fall back to linker symbol if "/memory" node not found or invalid */
+    end = RamEnd;
+  }
+  _Memory_Initialize( &_Memory_Areas[ 0 ], WorkAreaBase, end );
+}
+
+RTEMS_SYSINIT_ITEM(
+  bsp_memory_initialize,
+  RTEMS_SYSINIT_MEMORY,
+  RTEMS_SYSINIT_ORDER_MIDDLE
+);
+
+static const Memory_Information _Memory_Information =
+  MEMORY_INFORMATION_INITIALIZER( _Memory_Areas );
+
+const Memory_Information *_Memory_Get( void )
+{
+  return &_Memory_Information;
+}
diff --git a/spec/build/bsps/riscv/riscv/obj.yml b/spec/build/bsps/riscv/riscv/obj.yml
index 5e767be1bb..b2eb467824 100644
--- a/spec/build/bsps/riscv/riscv/obj.yml
+++ b/spec/build/bsps/riscv/riscv/obj.yml
@@ -29,6 +29,7 @@ source:
 - bsps/riscv/riscv/irq/irq.c
 - bsps/riscv/riscv/start/bsp_fatal_halt.c
 - bsps/riscv/riscv/start/bspstart.c
+- bsps/riscv/shared/start/bspgetworkarea.c
 - bsps/shared/cache/nocache.c
 - bsps/shared/dev/btimer/btimer-cpucounter.c
 - bsps/shared/dev/getentropy/getentropy-cpucounter.c
-- 
2.34.1