[U-Boot] [PATCH v3 1/3] fdt: add memory bank decoding functions for board setup

[Nathan Rossi]

Add two functions for use by board implementations to decode the memory
banks of the /memory node so as to populate the global data with
ram_size and board info for memory banks.

The fdtdec_setup_memory_size() function decodes the first memory bank
and sets up the gd->ram_size with the size of the memory bank. This
function should be called from the boards dram_init().

The fdtdec_setup_memory_banksize() function decode the memory banks
(up to the CONFIG_NR_DRAM_BANKS) and populates the base address and size
into the gd->bd->bi_dram array of banks. This function should be called
from the boards dram_init_banksize().

Signed-off-by: Nathan Rossi <nathan at nathanrossi.com>
Cc: Simon Glass <sjg at chromium.org>
Cc: Michal Simek <monstr at monstr.eu>
Reviewed-by: Simon Glass <sjg at chromium.org>
---
v2:
 * Make fdtdec_setup_memory_banksize() return value consistent
 * Add more detail into the function documentation
v3:
 * Wrap the fdtdec_setup_memory_banksize() function with an #if on
   CONFIG_NR_DRAM_BANKS, so that the function is only available for
   configs that have memory banks available in bd_t.

This implementation of decoding has been tested on zynq and zynqmp
boards with address/size cells of (1, 1), (1, 2), (2, 1), (2, 2) and
up to 2 memory banks.
---
 include/fdtdec.h | 34 ++++++++++++++++++++++++++++++++++
 lib/fdtdec.c     | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 90 insertions(+)

diff --git a/include/fdtdec.h b/include/fdtdec.h
index 27887c8c21..d074478f14 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -976,6 +976,40 @@ struct display_timing {
  */
 int fdtdec_decode_display_timing(const void *blob, int node, int index,
 				 struct display_timing *config);
+
+/**
+ * fdtdec_setup_memory_size() - decode and setup gd->ram_size
+ *
+ * Decode the /memory 'reg' property to determine the size of the first memory
+ * bank, populate the global data with the size 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 instead of
+ * hard coding the value in the case where the memory size cannot be detected
+ * automatically.
+ *
+ * @return 0 if OK, -EINVAL if the /memory node or reg property is missing or
+ * invalid
+ */
+int fdtdec_setup_memory_size(void);
+
+/**
+ * fdtdec_setup_memory_banksize() - decode and populate gd->bd->bi_dram
+ *
+ * Decode the /memory 'reg' property to determine the address and size of the
+ * memory banks. Use this data to populate the global data board info with the
+ * phys address and size of memory banks.
+ *
+ * This function should be called from a boards dram_init_banksize(). This
+ * helper function allows for boards to query the device tree for memory bank
+ * information instead of hard coding the information in cases where it cannot
+ * be detected automatically.
+ *
+ * @return 0 if OK, -EINVAL if the /memory node or reg property is missing or
+ * invalid
+ */
+int fdtdec_setup_memory_banksize(void);
+
 /**
  * Set up the device tree ready for use
  */
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 4e619c49a2..81f47ef2c7 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -1174,6 +1174,62 @@ int fdtdec_decode_display_timing(const void *blob, int parent, int index,
 	return ret;
 }
 
+int fdtdec_setup_memory_size(void)
+{
+	int ret, mem;
+	struct fdt_resource res;
+
+	mem = fdt_path_offset(gd->fdt_blob, "/memory");
+	if (mem < 0) {
+		debug("%s: Missing /memory node\n", __func__);
+		return -EINVAL;
+	}
+
+	ret = fdt_get_resource(gd->fdt_blob, mem, "reg", 0, &res);
+	if (ret != 0) {
+		debug("%s: Unable to decode first memory bank\n", __func__);
+		return -EINVAL;
+	}
+
+	gd->ram_size = (phys_size_t)(res.end - res.start + 1);
+	debug("%s: Initial DRAM size %llx\n", __func__, (u64)gd->ram_size);
+
+	return 0;
+}
+
+#if defined(CONFIG_NR_DRAM_BANKS)
+int fdtdec_setup_memory_banksize(void)
+{
+	int bank, ret, mem;
+	struct fdt_resource res;
+
+	mem = fdt_path_offset(gd->fdt_blob, "/memory");
+	if (mem < 0) {
+		debug("%s: Missing /memory node\n", __func__);
+		return -EINVAL;
+	}
+
+	for (bank = 0; bank < CONFIG_NR_DRAM_BANKS; bank++) {
+		ret = fdt_get_resource(gd->fdt_blob, mem, "reg", bank, &res);
+		if (ret == -FDT_ERR_NOTFOUND)
+			break;
+		if (ret != 0)
+			return -EINVAL;
+
+		gd->bd->bi_dram[bank].start = (phys_addr_t)res.start;
+		gd->bd->bi_dram[bank].size =
+			(phys_size_t)(res.end - res.start + 1);
+
+		debug("%s: DRAM Bank #%d: start = 0x%llx, size = 0x%llx\n",
+		      __func__, bank,
+		      (unsigned long long)gd->bd->bi_dram[bank].start,
+		      (unsigned long long)gd->bd->bi_dram[bank].size);
+	}
+
+	return 0;
+}
+#endif
+
 int fdtdec_setup(void)
 {
 #if CONFIG_IS_ENABLED(OF_CONTROL)
-- 
2.11.0