2 files changed, 135 insertions, 0 deletions

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 758b4f8b30b7..819e11209718 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
+#include <linux/sizes.h>
 #include <linux/string.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
@@ -440,6 +441,118 @@ struct boot_param_header *initial_boot_params;
 #ifdef CONFIG_OF_EARLY_FLATTREE
 
 /**
+ * res_mem_reserve_reg() - reserve all memory described in 'reg' property
+ */
+static int __init __reserved_mem_reserve_reg(unsigned long node,
+                                             const char *uname)
+{
+        int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
+        phys_addr_t base, size;
+        unsigned long len;
+        __be32 *prop;
+        int nomap;
+
+        prop = of_get_flat_dt_prop(node, "reg", &len);
+        if (!prop)
+                return -ENOENT;
+
+        if (len && len % t_len != 0) {
+                pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
+                       uname);
+                return -EINVAL;
+        }
+
+        nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
+
+        while (len >= t_len) {
+                base = dt_mem_next_cell(dt_root_addr_cells, &prop);
+                size = dt_mem_next_cell(dt_root_size_cells, &prop);
+
+                if (base && size &&
+                    early_init_dt_reserve_memory_arch(base, size, nomap) == 0)
+                        pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %ld MiB\n",
+                                uname, &base, (unsigned long)size / SZ_1M);
+                else
+                        pr_info("Reserved memory: failed to reserve memory for node '%s': base %pa, size %ld MiB\n",
+                                uname, &base, (unsigned long)size / SZ_1M);
+
+                len -= t_len;
+        }
+        return 0;
+}
+
+/**
+ * __reserved_mem_check_root() - check if #size-cells, #address-cells provided
+ * in /reserved-memory matches the values supported by the current implementation,
+ * also check if ranges property has been provided
+ */
+static int __reserved_mem_check_root(unsigned long node)
+{
+        __be32 *prop;
+
+        prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
+        if (!prop || be32_to_cpup(prop) != dt_root_size_cells)
+                return -EINVAL;
+
+        prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
+        if (!prop || be32_to_cpup(prop) != dt_root_addr_cells)
+                return -EINVAL;
+
+        prop = of_get_flat_dt_prop(node, "ranges", NULL);
+        if (!prop)
+                return -EINVAL;
+        return 0;
+}
+
+/**
+ * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
+ */
+static int __init __fdt_scan_reserved_mem(unsigned long node, const char *uname,
+                                          int depth, void *data)
+{
+        static int found;
+        const char *status;
+
+        if (!found && depth == 1 && strcmp(uname, "reserved-memory") == 0) {
+                if (__reserved_mem_check_root(node) != 0) {
+                        pr_err("Reserved memory: unsupported node format, ignoring\n");
+                        /* break scan */
+                        return 1;
+                }
+                found = 1;
+                /* scan next node */
+                return 0;
+        } else if (!found) {
+                /* scan next node */
+                return 0;
+        } else if (found && depth < 2) {
+                /* scanning of /reserved-memory has been finished */
+                return 1;
+        }
+
+        status = of_get_flat_dt_prop(node, "status", NULL);
+        if (status && strcmp(status, "okay") != 0 && strcmp(status, "ok") != 0)
+                return 0;
+
+        __reserved_mem_reserve_reg(node, uname);
+
+        /* scan next node */
+        return 0;
+}
+
+/**
+ * early_init_fdt_scan_reserved_mem() - create reserved memory regions
+ *
+ * This function grabs memory from early allocator for device exclusive use
+ * defined in device tree structures. It should be called by arch specific code
+ * once the early allocator (i.e. memblock) has been fully activated.
+ */
+void __init early_init_fdt_scan_reserved_mem(void)
+{
+        of_scan_flat_dt(__fdt_scan_reserved_mem, NULL);
+}
+
+/**
  * of_scan_flat_dt - scan flattened tree blob and call callback on each.
  * @it: callback function
  * @data: context data pointer
@@ -856,6 +969,16 @@ void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
         memblock_add(base, size);
 }
 
+int __init __weak early_init_dt_reserve_memory_arch(phys_addr_t base,
+                                        phys_addr_t size, bool nomap)
+{
+        if (memblock_is_region_reserved(base, size))
+                return -EBUSY;
+        if (nomap)
+                return memblock_remove(base, size);
+        return memblock_reserve(base, size);
+}
+
 /*
  * called from unflatten_device_tree() to bootstrap devicetree itself
  * Architectures can override this definition if memblock isn't used
@@ -864,6 +987,14 @@ void * __init __weak early_init_dt_alloc_memory_arch(u64 size, u64 align)
 {
         return __va(memblock_alloc(size, align));
 }
+#else
+int __init __weak early_init_dt_reserve_memory_arch(phys_addr_t base,
+                                        phys_addr_t size, bool nomap)
+{
+        pr_err("Reserved memory not supported, ignoring range 0x%llx - 0x%llx%s\n",
+                  base, size, nomap ? " (nomap)" : "");
+        return -ENOSYS;
+}
 #endif
 
 bool __init early_init_dt_scan(void *params)
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index 2b77058a7335..ddd7219af8ac 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -98,7 +98,10 @@ extern int early_init_dt_scan_chosen(unsigned long node, const char *uname,
                                      int depth, void *data);
 extern int early_init_dt_scan_memory(unsigned long node, const char *uname,
                                      int depth, void *data);
+extern void early_init_fdt_scan_reserved_mem(void);
 extern void early_init_dt_add_memory_arch(u64 base, u64 size);
+extern int early_init_dt_reserve_memory_arch(phys_addr_t base, phys_addr_t size,
+                                             bool no_map);
 extern void * early_init_dt_alloc_memory_arch(u64 size, u64 align);
 extern u64 dt_mem_next_cell(int s, __be32 **cellp);
 
@@ -118,6 +121,7 @@ extern void unflatten_and_copy_device_tree(void);
 extern void early_init_devtree(void *);
 extern void early_get_first_memblock_info(void *, phys_addr_t *);
 #else /* CONFIG_OF_FLATTREE */
+static inline void early_init_fdt_scan_reserved_mem(void) {}
 static inline const char *of_flat_dt_get_machine_name(void) { return NULL; }
 static inline void unflatten_device_tree(void) {}
 static inline void unflatten_and_copy_device_tree(void) {}