Implement memory regions iterators

include/dt/dt.h

@@ -236,6 +236,19 @@ error_t dt_get_prop_buffer(const fdt_t* fdt, dt_prop_t prop, buffer_t* bufOUT);
 [[gnu::nonnull(3)]]
 error_t dt_get_rsv_mem_entry(const fdt_t* fdt, u32 index, fdt_rsv_entry* entryOUT);
 
+/**
+ * @brief Get #address-cells and #size-cells properties from a node.
+ * @param fdt Pointer to the fdt object.
+ * @param node The node to read cell counts from.
+ * @param[out] address_cellsOUT Number of address cells (default 2).
+ * @param[out] size_cellsOUT Number of size cells (default 1).
+ * @retval ERR_NONE on success
+ * @retval ERR_BAD_ARG on nullptr args
+ * @retval ERR_NOT_VALID if the FDT is invalid or cell counts exceed 2
+ */
+[[gnu::nonnull(3, 4)]]
+error_t dt_get_reg_cell_counts(const fdt_t* fdt, dt_node_t node, u32* address_cellsOUT, u32* size_cellsOUT);
+
 /// @}
 
 #endif // !DT_DT

include/hal/memory_regions.h

@@ -9,7 +9,7 @@
  * Fields of this struct should not be modified directly.
  * */
 typedef struct {
-	alignas(16) u8 data[16];
+	alignas(16) u8 data[32];
 } hal_reserved_memory_iterator_t;
 
 /**
@@ -26,7 +26,7 @@ error_t hal_get_next_reserved_region(hal_reserved_memory_iterator_t* iter, memor
  * Fields of this struct should not be modified directly.
  * */
 typedef struct {
-	alignas(16) u8 data[16];
+	alignas(16) u8 data[32];
 } hal_memory_iterator_t;
 
 /**

src/lib/dt/dt_access.c

@@ -397,3 +397,41 @@ error_t dt_get_rsv_mem_entry(const fdt_t* fdt, u32 index, fdt_rsv_entry* entryOU
 
 	return ERR_NOT_VALID;
 }
+
+error_t dt_get_reg_cell_counts(const fdt_t* fdt, dt_node_t node, u32* address_cellsOUT, u32* size_cellsOUT) {
+	*address_cellsOUT = 2;
+	*size_cellsOUT = 1;
+
+	dt_prop_t address_cells_prop;
+	error_t err = dt_get_prop_by_name(fdt, node, "#address-cells", &address_cells_prop);
+	if (err == ERR_NONE) {
+		buffer_t buf;
+		err = dt_get_prop_buffer(fdt, address_cells_prop, &buf);
+		if (err)
+			return err;
+
+		if (!buffer_read_u32_be(buf, 0, address_cellsOUT) || *address_cellsOUT == 0)
+			return ERR_NOT_VALID;
+	} else if (err != ERR_NOT_FOUND) {
+		return err;
+	}
+
+	dt_prop_t size_cells_prop;
+	err = dt_get_prop_by_name(fdt, node, "#size-cells", &size_cells_prop);
+	if (err == ERR_NONE) {
+		buffer_t buf;
+		err = dt_get_prop_buffer(fdt, size_cells_prop, &buf);
+		if (err)
+			return err;
+
+		if (!buffer_read_u32_be(buf, 0, size_cellsOUT) || *size_cellsOUT == 0)
+			return ERR_NOT_VALID;
+	} else if (err != ERR_NOT_FOUND) {
+		return err;
+	}
+
+	if (*address_cellsOUT > 2 || *size_cellsOUT > 2)
+		return ERR_NOT_VALID;
+
+	return ERR_NONE;
+}