Permit decoding of a named memory region from the device tree. This allows
easy run-time configuration of the address of on-chip SRAM, SDRAM, etc.
Signed-off-by: Simon Glass <s...@chromium.org>
---
include/fdtdec.h | 28 ++++++++++++++++++++++++++
lib/fdtdec.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 89 insertions(+)
diff --git a/include/fdtdec.h b/include/fdtdec.h
index 8e9ebbb..8122ff2 100644
--- a/include/fdtdec.h
+++ b/include/fdtdec.h
@@ -647,4 +647,32 @@ int fdtdec_read_fmap_entry(const void *blob, int node,
const char *name,
*/
int fdtdec_decode_ram_size(const void *blob, const char *area, int board_id,
phys_addr_t *basep, phys_size_t *sizep, bd_t *bd);
+
+/**
+ * Decode a named region within a memory bank of a given type.
+ *
+ * This function handles selection of a memory region. The region is
+ * specified as an offset/size within a particular type of memory.
+ *
+ * The properties used are:
+ *
+ * <mem_type>-memory<suffix> for the name of the memory bank
+ * <mem_type>-offset<suffix> for the offset in that bank
+ *
+ * The property value must have an offset and a size. The function checks
+ * that the region is entirely within the memory bank.5
+ *
+ * @param blob FDT blob
+ * @param node Node containing the properties (-1 for /config)
+ * @param mem_type Type of memory to use, which is a name, such as
+ * "u-boot" or "kernel".
+ * @param suffix String to append to the memory/offset
+ * property names
+ * @param basep Returns base of region
+ * @param sizep Returns size of region
+ * @return 0 if OK, -ive on error
+ */
+int fdtdec_decode_memory_region(const void *blob, int node,
+ const char *mem_type, const char *suffix,
+ fdt_addr_t *basep, fdt_size_t *sizep);
#endif
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 65911fb..ab1ea77 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -828,4 +828,65 @@ int fdtdec_decode_ram_size(const void *blob, const char
*area, int board_id,
return 0;
}
+
+int fdtdec_decode_memory_region(const void *blob, int config_node,
+ const char *mem_type, const char *suffix,
+ fdt_addr_t *basep, fdt_size_t *sizep)
+{
+ char prop_name[50];
+ const char *mem;
+ fdt_size_t size, offset_size;
+ fdt_addr_t base, offset;
+ int node;
+
+ if (config_node == -1) {
+ config_node = fdt_path_offset(blob, "/config");
+ if (config_node < 0) {
+ debug("%s: Cannot find /config node\n", __func__);
+ return -ENOENT;
+ }
+ }
+ if (!suffix)
+ suffix = "";
+
+ snprintf(prop_name, sizeof(prop_name), "%s-memory%s", mem_type,
+ suffix);
+ mem = fdt_getprop(blob, config_node, prop_name, NULL);
+ if (!mem) {
+ debug("%s: No memory type for '%s', using /memory\n", __func__,
+ prop_name);
+ mem = "/memory";
+ }
+
+ node = fdt_path_offset(blob, mem);
+ if (node < 0) {
+ debug("%s: Failed to find node '%s': %s\n", __func__, mem,
+ fdt_strerror(node));
+ return -ENOENT;
+ }
+
+ /*
+ * Not strictly correct - the memory may have multiple banks. We just
+ * use the first
+ */
+ if (fdtdec_decode_region(blob, node, "reg", &base, &size)) {
+ debug("%s: Failed to decode memory region %s\n", __func__,
+ mem);
+ return -EINVAL;
+ }
+
+ snprintf(prop_name, sizeof(prop_name), "%s-offset%s", mem_type,
+ suffix);
+ if (fdtdec_decode_region(blob, config_node, prop_name, &offset,
+ &offset_size)) {
+ debug("%s: Failed to decode memory region '%s'\n", __func__,
+ prop_name);
+ return -EINVAL;
+ }
+
+ *basep = base + offset;
+ *sizep = offset_size;
+
+ return 0;
+}
#endif
--
2.1.0.rc2.206.gedb03e5
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