xen/dt: Move bootfdt functions to xen/bootfdt.h

Part of an unpicking process to extract bootfdt contents independent of bootinfo
to a separate file for x86 to take.

Move functions required for early FDT parsing from device_tree.h and arm's
setup.h onto bootfdt.h

Declaration motion only. Not a functional change.

Signed-off-by: Alejandro Vallejo <alejandro.garciavallejo@amd.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
Reviewed-by: Oleksii Kurochko<oleksii.kurochko@gmail.com> # riscv

xen/arch/riscv/cpufeature.c

@@ -8,6 +8,7 @@
  */
 
 #include <xen/bitmap.h>
+#include <xen/bootfdt.h>
 #include <xen/ctype.h>
 #include <xen/device_tree.h>
 #include <xen/errno.h>

xen/arch/riscv/smpboot.c

@@ -1,3 +1,4 @@
+#include <xen/bootfdt.h>
 #include <xen/cpumask.h>
 #include <xen/device_tree.h>
 #include <xen/errno.h>

xen/common/device-tree/bootfdt.c

@@ -215,18 +215,6 @@ u32 __init device_tree_get_u32(const void *fdt, int node,
     return fdt32_to_cpu(get_unaligned_t(uint32_t, prop->data));
 }
 
-/**
- * device_tree_for_each_node - iterate over all device tree sub-nodes
- * @fdt: flat device tree.
- * @node: parent node to start the search from
- * @func: function to call for each sub-node.
- * @data: data to pass to @func.
- *
- * Any nodes nested at DEVICE_TREE_MAX_DEPTH or deeper are ignored.
- *
- * Returns 0 if all nodes were iterated over successfully.  If @func
- * returns a value different from 0, that value is returned immediately.
- */
 int __init device_tree_for_each_node(const void *fdt, int node,
                                      device_tree_node_func func,
                                      void *data)

xen/common/device-tree/device-tree.c

@@ -8,6 +8,7 @@
  */
 
 #include <xen/bitops.h>
+#include <xen/bootfdt.h>
 #include <xen/types.h>
 #include <xen/init.h>
 #include <xen/guest_access.h>

xen/common/device-tree/static-evtchn.c

@@ -1,5 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
+#include <xen/bootfdt.h>
 #include <xen/event.h>
 #include <xen/static-evtchn.h>
 

xen/common/sched/boot-cpupool.c

@@ -7,6 +7,7 @@
  * Copyright (C) 2022 Arm Ltd.
  */
 
+#include <xen/bootfdt.h>
 #include <xen/acpi.h>
 #include <xen/sched.h>
 

xen/include/xen/bootfdt.h

@@ -2,8 +2,11 @@
 #ifndef XEN_BOOTFDT_H
 #define XEN_BOOTFDT_H
 
+#include <xen/byteorder.h>
+#include <xen/bug.h>
 #include <xen/types.h>
 #include <xen/kernel.h>
+#include <xen/lib.h>
 #include <xen/macros.h>
 #include <xen/xmalloc.h>
 
@@ -16,8 +19,92 @@
 #define NR_MEM_BANKS 256
 #define NR_SHMEM_BANKS 32
 
+/* Default #address and #size cells */
+#define DT_ROOT_NODE_ADDR_CELLS_DEFAULT 2
+#define DT_ROOT_NODE_SIZE_CELLS_DEFAULT 1
+
 #define MAX_MODULES 32 /* Current maximum useful modules */
 
+#define DEVICE_TREE_MAX_DEPTH 16
+
+/* Helper to read a big number; size is in cells (not bytes) */
+static inline u64 dt_read_number(const __be32 *cell, int size)
+{
+    u64 r = be32_to_cpu(*cell);
+
+    switch ( size )
+    {
+    case 1:
+        break;
+    case 2:
+        r = (r << 32) | be32_to_cpu(cell[1]);
+        break;
+    default:
+        /* Nonsensical size. default to 1 */
+        printk(XENLOG_ERR "dt_read_number(,%d) bad size\n", size);
+        ASSERT_UNREACHABLE();
+        break;
+    };
+
+    return r;
+}
+
+/* Wrapper for dt_read_number() to return paddr_t (instead of uint64_t) */
+static inline paddr_t dt_read_paddr(const __be32 *cell, int size)
+{
+    uint64_t dt_r;
+    paddr_t r;
+
+    /*
+     * dt_read_number will return uint64_t whereas paddr_t may not be 64-bit.
+     * Thus, there is an implicit cast from uint64_t to paddr_t.
+     */
+    dt_r = dt_read_number(cell, size);
+
+    if ( dt_r != (paddr_t)dt_r )
+    {
+        printk("Physical address greater than max width supported\n");
+        WARN();
+    }
+
+    /*
+     * Xen will truncate the address/size if it is greater than the maximum
+     * supported width and it will give an appropriate warning.
+     */
+    r = dt_r;
+
+    return r;
+}
+
+static inline u64 dt_next_cell(int s, const __be32 **cellp)
+{
+    const __be32 *p = *cellp;
+
+    *cellp = p + s;
+    return dt_read_number(p, s);
+}
+
+typedef int (*device_tree_node_func)(const void *fdt,
+                                     int node, const char *name, int depth,
+                                     u32 address_cells, u32 size_cells,
+                                     void *data);
+
+/**
+ * device_tree_for_each_node - iterate over all device tree sub-nodes
+ * @fdt: flat device tree.
+ * @node: parent node to start the search from
+ * @func: function to call for each sub-node.
+ * @data: data to pass to @func.
+ *
+ * Any nodes nested at DEVICE_TREE_MAX_DEPTH or deeper are ignored.
+ *
+ * Returns 0 if all nodes were iterated over successfully.  If @func
+ * returns a value different from 0, that value is returned immediately.
+ */
+int device_tree_for_each_node(const void *fdt, int node,
+                              device_tree_node_func func,
+                              void *data);
+
 typedef enum {
     BOOTMOD_XEN,
     BOOTMOD_FDT,
@@ -261,4 +348,20 @@ static inline struct membanks *membanks_xzalloc(unsigned int nr,
     return banks;
 }
 
+/*
+ * Interpret the property `prop_name` of `node` as a u32.
+ *
+ * Returns the property value on success; otherwise returns `dflt`.
+ */
+u32 device_tree_get_u32(const void *fdt, int node,
+                        const char *prop_name, u32 dflt);
+
+/*
+ * Interpret the property `prop_name` of `node` as a "reg".
+ *
+ * Returns outputs in `start` and `size`.
+ */
+void device_tree_get_reg(const __be32 **cell, uint32_t address_cells,
+                         uint32_t size_cells, paddr_t *start, paddr_t *size);
+
 #endif /* XEN_BOOTFDT_H */

xen/include/xen/device_tree.h

@@ -22,8 +22,6 @@
 #include <xen/list.h>
 #include <xen/rwlock.h>
 
-#define DEVICE_TREE_MAX_DEPTH 16
-
 /*
  * Struct used for matching a device
  */
@@ -164,17 +162,8 @@ struct dt_raw_irq {
     u32 specifier[DT_MAX_IRQ_SPEC];
 };
 
-typedef int (*device_tree_node_func)(const void *fdt,
-                                     int node, const char *name, int depth,
-                                     u32 address_cells, u32 size_cells,
-                                     void *data);
-
 extern const void *device_tree_flattened;
 
-int device_tree_for_each_node(const void *fdt, int node,
-                              device_tree_node_func func,
-                              void *data);
-
 /**
  * dt_unflatten_host_device_tree - Unflatten the host device tree
  *
@@ -245,10 +234,6 @@ void intc_dt_preinit(void);
 #define dt_node_cmp(s1, s2) strcasecmp((s1), (s2))
 #define dt_compat_cmp(s1, s2) strcasecmp((s1), (s2))
 
-/* Default #address and #size cells */
-#define DT_ROOT_NODE_ADDR_CELLS_DEFAULT 2
-#define DT_ROOT_NODE_SIZE_CELLS_DEFAULT 1
-
 #define dt_for_each_property_node(dn, pp)                   \
     for ( pp = (dn)->properties; (pp) != NULL; pp = (pp)->next )
 
@@ -258,55 +243,6 @@ void intc_dt_preinit(void);
 #define dt_for_each_child_node(dt, dn)                      \
     for ( dn = (dt)->child; (dn) != NULL; dn = (dn)->sibling )
 
-/* Helper to read a big number; size is in cells (not bytes) */
-static inline u64 dt_read_number(const __be32 *cell, int size)
-{
-    u64 r = be32_to_cpu(*cell);
-
-    switch ( size )
-    {
-    case 1:
-        break;
-    case 2:
-        r = (r << 32) | be32_to_cpu(cell[1]);
-        break;
-    default:
-        /* Nonsensical size. default to 1 */
-        printk(XENLOG_ERR "dt_read_number(,%d) bad size\n", size);
-        ASSERT_UNREACHABLE();
-        break;
-    };
-
-    return r;
-}
-
-/* Wrapper for dt_read_number() to return paddr_t (instead of uint64_t) */
-static inline paddr_t dt_read_paddr(const __be32 *cell, int size)
-{
-    uint64_t dt_r;
-    paddr_t r;
-
-    /*
-     * dt_read_number will return uint64_t whereas paddr_t may not be 64-bit.
-     * Thus, there is an implicit cast from uint64_t to paddr_t.
-     */
-    dt_r = dt_read_number(cell, size);
-
-    if ( dt_r != (paddr_t)dt_r )
-    {
-        printk("Physical address greater than max width supported\n");
-        WARN();
-    }
-
-    /*
-     * Xen will truncate the address/size if it is greater than the maximum
-     * supported width and it will give an appropriate warning.
-     */
-    r = dt_r;
-
-    return r;
-}
-
 /* Helper to convert a number of cells to bytes */
 static inline int dt_cells_to_size(int size)
 {
@@ -319,14 +255,6 @@ static inline int dt_size_to_cells(int bytes)
     return (bytes / sizeof(u32));
 }
 
-static inline u64 dt_next_cell(int s, const __be32 **cellp)
-{
-    const __be32 *p = *cellp;
-
-    *cellp = p + s;
-    return dt_read_number(p, s);
-}
-
 static inline const char *dt_node_full_name(const struct dt_device_node *np)
 {
     return (np && np->full_name) ? np->full_name : "<no-node>";
@@ -984,12 +912,6 @@ int dt_map_id(const struct dt_device_node *np, uint32_t id,
 
 struct dt_device_node *dt_find_node_by_phandle(dt_phandle handle);
 
-void device_tree_get_reg(const __be32 **cell, uint32_t address_cells,
-                         uint32_t size_cells, paddr_t *start, paddr_t *size);
-
-u32 device_tree_get_u32(const void *fdt, int node,
-                        const char *prop_name, u32 dflt);
-
 #ifdef CONFIG_DEVICE_TREE_DEBUG
 #define dt_dprintk(fmt, args...)  \
     printk(XENLOG_DEBUG fmt, ## args)