[PATCH 1/4] fdtdec: Add fdtdec_get_mem_size_base()

[Bin Meng <bmeng.cn@gmail.com>]

From: Bin Meng <bin.meng@windriver.com>

This adds a new API fdtdec_get_mem_size_base() that does similar
thing to fdtdec_setup_mem_size_base_fdt(), but without assigning
gd->ram_size and gd->ram_base.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
---

 include/fdtdec.h | 22 ++++++++++++++++++++++
 lib/fdtdec.c     | 24 ++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/include/fdtdec.h b/include/fdtdec.h
index abd6d42..460d57a 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -909,6 +909,28 @@ int fdtdec_decode_display_timing(const void *blob, int node, int index,
 				 struct display_timing *config);
 
 /**
+ * fdtdec_get_mem_size_base() - decode FDT to get ram size and base
+ *
+ * Decode the /memory 'reg' property to determine the size and start of the
+ * first memory bank, populate the global data with the size and start of the
+ * first bank of memory.
+ *
+ * This function should be called from a boards dram_init(). This helper
+ * function allows for boards to query the device tree for DRAM size and start
+ * address instead of hard coding the value in the case where the memory size
+ * and start address cannot be detected automatically.
+ *
+ * @param blob		FDT blob
+ * @param ram_size	buffer to hold the ram size to set
+ * @param ram_base	buffer to hold the ram base to set
+ *
+ * @return 0 if OK, -EINVAL if the /memory node or reg property is missing or
+ * invalid
+ */
+int fdtdec_get_mem_size_base(const void *blob,
+			     phys_size_t *ram_size, unsigned long *ram_base);
+
+/**
  * fdtdec_setup_mem_size_base_fdt() - decode and setup gd->ram_size and
  * gd->ram_start
  *
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 0dd7ff1..078ff7a 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -1030,6 +1030,30 @@ int fdtdec_decode_display_timing(const void *blob, int parent, int index,
 	return ret;
 }
 
+int fdtdec_get_mem_size_base(const void *blob,
+			     phys_size_t *ram_size, unsigned long *ram_base)
+{
+	int ret, mem;
+	struct fdt_resource res;
+
+	mem = fdt_path_offset(blob, "/memory");
+	if (mem < 0) {
+		debug("%s: Missing /memory node\n", __func__);
+		return -EINVAL;
+	}
+
+	ret = fdt_get_resource(blob, mem, "reg", 0, &res);
+	if (ret != 0) {
+		debug("%s: Unable to decode first memory bank\n", __func__);
+		return -EINVAL;
+	}
+
+	*ram_size = (phys_size_t)(res.end - res.start + 1);
+	*ram_base = (unsigned long)res.start;
+
+	return 0;
+}
+
 int fdtdec_setup_mem_size_base_fdt(const void *blob)
 {
 	int ret, mem;
-- 
2.7.4