#include "libfdt_env.h"
#include <fdt.h>
#include <libfdt.h>
#include "libfdt_internal.h"
/**
* overlay_get_target_phandle - retrieves the target phandle of a fragment
* @fdto: pointer to the device tree overlay blob
* @fragment: node offset of the fragment in the overlay
*
* overlay_get_target_phandle() retrieves the target phandle of an
* overlay fragment when that fragment uses a phandle (target
* property) instead of a path (target-path property).
*
* returns:
* the phandle pointed by the target property
* 0, if the phandle was not found
* -1, if the phandle was malformed
*/
static uint32_t overlay_get_target_phandle(const void *fdto, int fragment)
{
const fdt32_t *val;
int len;
val = fdt_getprop(fdto, fragment, "target", &len);
if (!val)
return 0;
if ((len != sizeof(*val)) || (fdt32_to_cpu(*val) == (uint32_t)-1))
return (uint32_t)-1;
return fdt32_to_cpu(*val);
}
/**
* overlay_get_target - retrieves the offset of a fragment's target
* @fdt: Base device tree blob
* @fdto: Device tree overlay blob
* @fragment: node offset of the fragment in the overlay
*
* overlay_get_target() retrieves the target offset in the base
* device tree of a fragment, no matter how the actual targetting is
* done (through a phandle or a path)
*
* returns:
* the targetted node offset in the base device tree
* Negative error code on error
*/
static int overlay_get_target(const void *fdt, const void *fdto,
int fragment)
{
uint32_t phandle;
const char *path;
int path_len;
/* Try first to do a phandle based lookup */
phandle = overlay_get_target_phandle(fdto, fragment);
if (phandle == (uint32_t)-1)
return -FDT_ERR_BADPHANDLE;
if (phandle)
return fdt_node_offset_by_phandle(fdt, phandle);
/* And then a path based lookup */
path = fdt_getprop(fdto, fragment, "target-path", &path_len);
if (!path) {
/*
* If we haven't found either a target or a
* target-path property in a node that contains a
* __overlay__ subnode (we wouldn't be called
* otherwise), consider it a improperly written
* overlay
*/
if (path_len == -FDT_ERR_NOTFOUND)
return -FDT_ERR_BADOVERLAY;
return path_len;
}
return fdt_path_offset(fdt, path);
}
/**
* overlay_phandle_add_offset - Increases a phandle by an offset
* @fdt: Base device tree blob
* @node: Device tree overlay blob
* @name: Name of the property to modify (phandle or linux,phandle)
* @delta: offset to apply
*
* overlay_phandle_add_offset() increments a node phandle by a given
* offset.
*
* returns:
* 0 on success.
* Negative error code on error
*/
static int overlay_phandle_add_offset(void *fdt, int node,
const char *name, uint32_t delta)
{
const fdt32_t *val;
uint32_t adj_val;
int len;
val = fdt_getprop(fdt, node, name, &len);
if (!val)
return len;
if (len != sizeof(*val))
return -FDT_ERR_BADPHANDLE;
adj_val = fdt32_to_cpu(*val);
if ((adj_val + delta) < adj_val)
return -FDT_ERR_NOPHANDLES;
adj_val += delta;
if (adj_val == (uint32_t)-1)
return -FDT_ERR_NOPHANDLES;
return fdt_setprop_inplace_u32(fdt, node, name, adj_val);
}
/**
* overlay_adjust_node_phandles - Offsets the phandles of a node
* @fdto: Device tree overlay blob
* @node: Offset of the node we want to adjust
* @delta: Offset to shift the phandles of
*
* overlay_adjust_node_phandles() adds a constant to all the phandles
* of a given node. This is mainly use as part of the overlay
* application process, when we want to update all the overlay
* phandles to not conflict with the overlays of the base device tree.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_adjust_node_phandles(void *fdto, int node,
uint32_t delta)
{
int child;
int ret;
ret = overlay_phandle_add_offset(fdto, node, "phandle", delta);
if (ret && ret != -FDT_ERR_NOTFOUND)
return ret;
ret = overlay_phandle_add_offset(fdto, node, "linux,phandle", delta);
if (ret && ret != -FDT_ERR_NOTFOUND)
return ret;
fdt_for_each_subnode(child, fdto, node) {
ret = overlay_adjust_node_phandles(fdto, child, delta);
if (ret)
return ret;
}
return 0;
}
/**
* overlay_adjust_local_phandles - Adjust the phandles of a whole overlay
* @fdto: Device tree overlay blob
* @delta: Offset to shift the phandles of
*
* overlay_adjust_local_phandles() adds a constant to all the
* phandles of an overlay. This is mainly use as part of the overlay
* application process, when we want to update all the overlay
* phandles to not conflict with the overlays of the base device tree.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_adjust_local_phandles(void *fdto, uint32_t delta)
{
/*
* Start adjusting the phandles from the overlay root
*/
return overlay_adjust_node_phandles(fdto, 0, delta);
}
/**
* overlay_update_local_node_references - Adjust the overlay references
* @fdto: Device tree overlay blob
* @tree_node: Node offset of the node to operate on
* @fixup_node: Node offset of the matching local fixups node
* @delta: Offset to shift the phandles of
*
* overlay_update_local_nodes_references() update the phandles
* pointing to a node within the device tree overlay by adding a
* constant delta.
*
* This is mainly used as part of a device tree application process,
* where you want the device tree overlays phandles to not conflict
* with the ones from the base device tree before merging them.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_update_local_node_references(void *fdto,
int tree_node,
int fixup_node,
uint32_t delta)
{
int fixup_prop;
int fixup_child;
int ret;
fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) {
const fdt32_t *fixup_val;
const char *tree_val;
const char *name;
int fixup_len;
int tree_len;
int i;
fixup_val = fdt_getprop_by_offset(fdto, fixup_prop,
&name, &fixup_len);
if (!fixup_val)
return fixup_len;
if (fixup_len % sizeof(uint32_t))
return -FDT_ERR_BADOVERLAY;
tree_val = fdt_getprop(fdto, tree_node, name, &tree_len);
if (!tree_val) {
if (tree_len == -FDT_ERR_NOTFOUND)
return -FDT_ERR_BADOVERLAY;
return tree_len;
}
for (i = 0; i < (fixup_len / sizeof(uint32_t)); i++) {
fdt32_t adj_val;
uint32_t poffset;
poffset = fdt32_to_cpu(fixup_val[i]);
/*
* phandles to fixup can be unaligned.
*
* Use a memcpy for the architectures that do
* not support unaligned accesses.
*/
memcpy(&adj_val, tree_val + poffset, sizeof(adj_val));
adj_val = cpu_to_fdt32(fdt32_to_cpu(adj_val) + delta);
ret = fdt_setprop_inplace_namelen_partial(fdto,
tree_node,
name,
strlen(name),
poffset,
&adj_val,
sizeof(adj_val));
if (ret == -FDT_ERR_NOSPACE)
return -FDT_ERR_BADOVERLAY;
if (ret)
return ret;
}
}
fdt_for_each_subnode(fixup_child, fdto, fixup_node) {
const char *fixup_child_name = fdt_get_name(fdto, fixup_child,
NULL);
int tree_child;
tree_child = fdt_subnode_offset(fdto, tree_node,
fixup_child_name);
if (tree_child == -FDT_ERR_NOTFOUND)
return -FDT_ERR_BADOVERLAY;
if (tree_child < 0)
return tree_child;
ret = overlay_update_local_node_references(fdto,
tree_child,
fixup_child,
delta);
if (ret)
return ret;
}
return 0;
}
/**
* overlay_update_local_references - Adjust the overlay references
* @fdto: Device tree overlay blob
* @delta: Offset to shift the phandles of
*
* overlay_update_local_references() update all the phandles pointing
* to a node within the device tree overlay by adding a constant
* delta to not conflict with the base overlay.
*
* This is mainly used as part of a device tree application process,
* where you want the device tree overlays phandles to not conflict
* with the ones from the base device tree before merging them.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_update_local_references(void *fdto, uint32_t delta)
{
int fixups;
fixups = fdt_path_offset(fdto, "/__local_fixups__");
if (fixups < 0) {
/* There's no local phandles to adjust, bail out */
if (fixups == -FDT_ERR_NOTFOUND)
return 0;
return fixups;
}
/*
* Update our local references from the root of the tree
*/
return overlay_update_local_node_references(fdto, 0, fixups,
delta);
}
/**
* overlay_fixup_one_phandle - Set an overlay phandle to the base one
* @fdt: Base Device Tree blob
* @fdto: Device tree overlay blob
* @symbols_off: Node offset of the symbols node in the base device tree
* @path: Path to a node holding a phandle in the overlay
* @path_len: number of path characters to consider
* @name: Name of the property holding the phandle reference in the overlay
* @name_len: number of name characters to consider
* @poffset: Offset within the overlay property where the phandle is stored
* @label: Label of the node referenced by the phandle
*
* overlay_fixup_one_phandle() resolves an overlay phandle pointing to
* a node in the base device tree.
*
* This is part of the device tree overlay application process, when
* you want all the phandles in the overlay to point to the actual
* base dt nodes.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_fixup_one_phandle(void *fdt, void *fdto,
int symbols_off,
const char *path, uint32_t path_len,
const char *name, uint32_t name_len,
int poffset, const char *label)
{
const char *symbol_path;
uint32_t phandle;
fdt32_t phandle_prop;
int symbol_off, fixup_off;
int prop_len;
if (symbols_off < 0)
return symbols_off;
symbol_path = fdt_getprop(fdt, symbols_off, label,
&prop_len);
if (!symbol_path)
return prop_len;
symbol_off = fdt_path_offset(fdt, symbol_path);
if (symbol_off < 0)
return symbol_off;
phandle = fdt_get_phandle(fdt, symbol_off);
if (!phandle)
return -FDT_ERR_NOTFOUND;
fixup_off = fdt_path_offset_namelen(fdto, path, path_len);
if (fixup_off == -FDT_ERR_NOTFOUND)
return -FDT_ERR_BADOVERLAY;
if (fixup_off < 0)
return fixup_off;
phandle_prop = cpu_to_fdt32(phandle);
return fdt_setprop_inplace_namelen_partial(fdto, fixup_off,
name, name_len, poffset,
&phandle_prop,
sizeof(phandle_prop));
};
/**
* overlay_fixup_phandle - Set an overlay phandle to the base one
* @fdt: Base Device Tree blob
* @fdto: Device tree overlay blob
* @symbols_off: Node offset of the symbols node in the base device tree
* @property: Property offset in the overlay holding the list of fixups
*
* overlay_fixup_phandle() resolves all the overlay phandles pointed
* to in a __fixups__ property, and updates them to match the phandles
* in use in the base device tree.
*
* This is part of the device tree overlay application process, when
* you want all the phandles in the overlay to point to the actual
* base dt nodes.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off,
int property)
{
const char *value;
const char *label;
int len;
value = fdt_getprop_by_offset(fdto, property,
&label, &len);
if (!value) {
if (len == -FDT_ERR_NOTFOUND)
return -FDT_ERR_INTERNAL;
return len;
}
do {
const char *path, *name, *fixup_end;
const char *fixup_str = value;
uint32_t path_len, name_len;
uint32_t fixup_len;
char *sep, *endptr;
int poffset, ret;
fixup_end = memchr(value, '\0', len);
if (!fixup_end)
return -FDT_ERR_BADOVERLAY;
fixup_len = fixup_end - fixup_str;
len -= fixup_len + 1;
value += fixup_len + 1;
path = fixup_str;
sep = memchr(fixup_str, ':', fixup_len);
if (!sep || *sep != ':')
return -FDT_ERR_BADOVERLAY;
path_len = sep - path;
if (path_len == (fixup_len - 1))
return -FDT_ERR_BADOVERLAY;
fixup_len -= path_len + 1;
name = sep + 1;
sep = memchr(name, ':', fixup_len);
if (!sep || *sep != ':')
return -FDT_ERR_BADOVERLAY;
name_len = sep - name;
if (!name_len)
return -FDT_ERR_BADOVERLAY;
poffset = strtoul(sep + 1, &endptr, 10);
if ((*endptr != '\0') || (endptr <= (sep + 1)))
return -FDT_ERR_BADOVERLAY;
ret = overlay_fixup_one_phandle(fdt, fdto, symbols_off,
path, path_len, name, name_len,
poffset, label);
if (ret)
return ret;
} while (len > 0);
return 0;
}
/**
* overlay_fixup_phandles - Resolve the overlay phandles to the base
* device tree
* @fdt: Base Device Tree blob
* @fdto: Device tree overlay blob
*
* overlay_fixup_phandles() resolves all the overlay phandles pointing
* to nodes in the base device tree.
*
* This is one of the steps of the device tree overlay application
* process, when you want all the phandles in the overlay to point to
* the actual base dt nodes.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_fixup_phandles(void *fdt, void *fdto)
{
int fixups_off, symbols_off;
int property;
/* We can have overlays without any fixups */
fixups_off = fdt_path_offset(fdto, "/__fixups__");
if (fixups_off == -FDT_ERR_NOTFOUND)
return 0; /* nothing to do */
if (fixups_off < 0)
return fixups_off;
/* And base DTs without symbols */
symbols_off = fdt_path_offset(fdt, "/__symbols__");
if ((symbols_off < 0 && (symbols_off != -FDT_ERR_NOTFOUND)))
return symbols_off;
fdt_for_each_property_offset(property, fdto, fixups_off) {
int ret;
ret = overlay_fixup_phandle(fdt, fdto, symbols_off, property);
if (ret)
return ret;
}
return 0;
}
/**
* overlay_apply_node - Merges a node into the base device tree
* @fdt: Base Device Tree blob
* @target: Node offset in the base device tree to apply the fragment to
* @fdto: Device tree overlay blob
* @node: Node offset in the overlay holding the changes to merge
*
* overlay_apply_node() merges a node into a target base device tree
* node pointed.
*
* This is part of the final step in the device tree overlay
* application process, when all the phandles have been adjusted and
* resolved and you just have to merge overlay into the base device
* tree.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_apply_node(void *fdt, int target,
void *fdto, int node)
{
int property;
int subnode;
fdt_for_each_property_offset(property, fdto, node) {
const char *name;
const void *prop;
int prop_len;
int ret;
prop = fdt_getprop_by_offset(fdto, property, &name,
&prop_len);
if (prop_len == -FDT_ERR_NOTFOUND)
return -FDT_ERR_INTERNAL;
if (prop_len < 0)
return prop_len;
ret = fdt_setprop(fdt, target, name, prop, prop_len);
if (ret)
return ret;
}
fdt_for_each_subnode(subnode, fdto, node) {
const char *name = fdt_get_name(fdto, subnode, NULL);
int nnode;
int ret;
nnode = fdt_add_subnode(fdt, target, name);
if (nnode == -FDT_ERR_EXISTS) {
nnode = fdt_subnode_offset(fdt, target, name);
if (nnode == -FDT_ERR_NOTFOUND)
return -FDT_ERR_INTERNAL;
}
if (nnode < 0)
return nnode;
ret = overlay_apply_node(fdt, nnode, fdto, subnode);
if (ret)
return ret;
}
return 0;
}
/**
* overlay_merge - Merge an overlay into its base device tree
* @fdt: Base Device Tree blob
* @fdto: Device tree overlay blob
*
* overlay_merge() merges an overlay into its base device tree.
*
* This is the final step in the device tree overlay application
* process, when all the phandles have been adjusted and resolved and
* you just have to merge overlay into the base device tree.
*
* returns:
* 0 on success
* Negative error code on failure
*/
static int overlay_merge(void *fdt, void *fdto)
{
int fragment;
fdt_for_each_subnode(fragment, fdto, 0) {
int overlay;
int target;
int ret;
/*
* Each fragments will have an __overlay__ node. If
* they don't, it's not supposed to be merged
*/
overlay = fdt_subnode_offset(fdto, fragment, "__overlay__");
if (overlay == -FDT_ERR_NOTFOUND)
continue;
if (overlay < 0)
return overlay;
target = overlay_get_target(fdt, fdto, fragment);
if (target < 0)
return target;
ret = overlay_apply_node(fdt, target, fdto, overlay);
if (ret)
return ret;
}
return 0;
}
int fdt_overlay_apply(void *fdt, void *fdto)
{
uint32_t delta = fdt_get_max_phandle(fdt);
int ret;
FDT_CHECK_HEADER(fdt);
FDT_CHECK_HEADER(fdto);
ret = overlay_adjust_local_phandles(fdto, delta);
if (ret)
goto err;
ret = overlay_update_local_references(fdto, delta);
if (ret)
goto err;
ret = overlay_fixup_phandles(fdt, fdto);
if (ret)
goto err;
ret = overlay_merge(fdt, fdto);
if (ret)
goto err;
/*
* The overlay has been damaged, erase its magic.
*/
fdt_set_magic(fdto, ~0);
return 0;
err:
/*
* The overlay might have been damaged, erase its magic.
*/
fdt_set_magic(fdto, ~0);
/*
* The base device tree might have been damaged, erase its
* magic.
*/
fdt_set_magic(fdt, ~0);
return ret;
}