The device tree overlays are a good way to deal with user-modifyable boards or boards with some kind of an expansion mechanism where we can easily plug new board in (like the BBB, the Raspberry Pi or the CHIP). Add a new function to merge overlays with a base device tree. Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>master
Maxime Ripard
9 years ago
committed by
Tom Rini
parent
ea7b1a213e
commit
ddf67f7135
@ -0,0 +1,405 @@ |
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#include "libfdt_env.h" |
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#include <fdt.h> |
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#include <libfdt.h> |
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#include "libfdt_internal.h" |
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static uint32_t overlay_get_target_phandle(const void *fdto, int fragment) |
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{ |
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const uint32_t *val; |
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int len; |
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val = fdt_getprop(fdto, fragment, "target", &len); |
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if (!val) |
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return 0; |
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if ((*val == 0xffffffff) || (len != sizeof(*val))) |
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return 0xffffffff; |
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return fdt32_to_cpu(*val); |
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} |
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static int overlay_get_target(const void *fdt, const void *fdto, |
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int fragment) |
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{ |
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uint32_t phandle; |
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const char *path; |
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/* Try first to do a phandle based lookup */ |
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phandle = overlay_get_target_phandle(fdto, fragment); |
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if (phandle == -1) |
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return -FDT_ERR_BADPHANDLE; |
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if (phandle) |
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return fdt_node_offset_by_phandle(fdt, phandle); |
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/* And then a path based lookup */ |
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path = fdt_getprop(fdto, fragment, "target-path", NULL); |
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if (!path) |
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return -FDT_ERR_NOTFOUND; |
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return fdt_path_offset(fdt, path); |
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} |
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static int overlay_phandle_add_offset(void *fdt, int node, |
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const char *name, uint32_t delta) |
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{ |
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const uint32_t *val; |
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uint32_t adj_val; |
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int len; |
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val = fdt_getprop(fdt, node, name, &len); |
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if (!val) |
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return len; |
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if (len != sizeof(*val)) |
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return -FDT_ERR_BADSTRUCTURE; |
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adj_val = fdt32_to_cpu(*val); |
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if ((adj_val + delta) < adj_val) |
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return -FDT_ERR_BADPHANDLE; |
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adj_val += delta; |
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return fdt_setprop_inplace_u32(fdt, node, name, adj_val); |
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} |
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static int overlay_adjust_node_phandles(void *fdto, int node, |
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uint32_t delta) |
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{ |
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bool found = false; |
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int child; |
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int ret; |
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ret = overlay_phandle_add_offset(fdto, node, "phandle", delta); |
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if (ret && ret != -FDT_ERR_NOTFOUND) |
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return ret; |
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if (!ret) |
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found = true; |
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ret = overlay_phandle_add_offset(fdto, node, "linux,phandle", delta); |
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if (ret && ret != -FDT_ERR_NOTFOUND) |
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return ret; |
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/*
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* If neither phandle nor linux,phandle have been found return |
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* an error. |
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*/ |
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if (!found && !ret) |
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return ret; |
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fdt_for_each_subnode(fdto, child, node) |
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overlay_adjust_node_phandles(fdto, child, delta); |
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return 0; |
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} |
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static int overlay_adjust_local_phandles(void *fdto, uint32_t delta) |
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{ |
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/*
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* Start adjusting the phandles from the overlay root |
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*/ |
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return overlay_adjust_node_phandles(fdto, 0, delta); |
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} |
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static int overlay_update_local_node_references(void *fdto, |
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int tree_node, |
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int fixup_node, |
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uint32_t delta) |
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{ |
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int fixup_prop; |
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int fixup_child; |
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int ret; |
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fdt_for_each_property_offset(fixup_prop, fdto, fixup_node) { |
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const uint32_t *val = NULL; |
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uint32_t adj_val, index; |
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const char *name; |
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int fixup_len; |
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int tree_len; |
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val = fdt_getprop_by_offset(fdto, fixup_prop, |
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&name, &fixup_len); |
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if (!val) |
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return fixup_len; |
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index = fdt32_to_cpu(*val); |
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val = fdt_getprop(fdto, tree_node, name, &tree_len); |
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if (!val) |
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return tree_len; |
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/*
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* The index can be unaligned. |
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* |
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* Use a memcpy for the architectures that do not |
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* support unaligned accesses. |
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*/ |
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memcpy(&adj_val, (unsigned char *)val + index, |
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sizeof(uint32_t)); |
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adj_val = fdt32_to_cpu(adj_val); |
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adj_val += delta; |
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adj_val = cpu_to_fdt32(adj_val); |
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ret = fdt_setprop_inplace_namelen_by_index(fdto, tree_node, |
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name, strlen(name), |
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index, &adj_val, |
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sizeof(adj_val)); |
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if (ret) |
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return ret; |
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} |
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fdt_for_each_subnode(fdto, fixup_child, fixup_node) { |
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const char *fixup_child_name = fdt_get_name(fdto, fixup_child, |
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NULL); |
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int tree_child; |
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tree_child = fdt_subnode_offset(fdto, tree_node, |
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fixup_child_name); |
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if (tree_child < 0) |
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return tree_child; |
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ret = overlay_update_local_node_references(fdto, |
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tree_child, |
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fixup_child, |
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delta); |
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if (ret) |
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return ret; |
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} |
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return 0; |
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} |
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static int overlay_update_local_references(void *dto, uint32_t delta) |
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{ |
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int fixups; |
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fixups = fdt_path_offset(dto, "/__local_fixups__"); |
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if (fixups < 0) { |
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/* There's no local phandles to adjust, bail out */ |
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if (fixups == -FDT_ERR_NOTFOUND) |
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return 0; |
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return fixups; |
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} |
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/*
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* Update our local references from the root of the tree |
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*/ |
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return overlay_update_local_node_references(dto, 0, fixups, |
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delta); |
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} |
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static int overlay_fixup_one_phandle(void *fdt, void *fdto, |
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int symbols_off, |
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const char *path, uint32_t path_len, |
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const char *name, uint32_t name_len, |
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int index, const char *label) |
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{ |
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const char *symbol_path; |
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uint32_t phandle; |
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int symbol_off, fixup_off; |
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int prop_len; |
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symbol_path = fdt_getprop(fdt, symbols_off, label, |
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&prop_len); |
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if (!symbol_path) |
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return -FDT_ERR_NOTFOUND; |
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symbol_off = fdt_path_offset(fdt, symbol_path); |
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if (symbol_off < 0) |
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return symbol_off; |
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phandle = fdt_get_phandle(fdt, symbol_off); |
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if (!phandle) |
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return -FDT_ERR_NOTFOUND; |
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fixup_off = fdt_path_offset_namelen(fdto, path, path_len); |
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if (fixup_off < 0) |
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return fixup_off; |
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phandle = cpu_to_fdt32(phandle); |
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return fdt_setprop_inplace_namelen_by_index(fdto, fixup_off, |
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name, name_len, index, |
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&phandle, sizeof(phandle)); |
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}; |
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static int overlay_fixup_phandle(void *fdt, void *fdto, int symbols_off, |
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int property) |
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{ |
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const char *value; |
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const char *label; |
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int len; |
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value = fdt_getprop_by_offset(fdto, property, |
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&label, &len); |
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if (!value) |
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return len; |
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do { |
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const char *prop_string = value; |
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const char *path, *name; |
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uint32_t prop_len = strlen(value); |
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uint32_t path_len, name_len; |
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char *sep, *endptr; |
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int index; |
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int ret; |
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path = prop_string; |
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sep = memchr(prop_string, ':', prop_len); |
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if (*sep != ':') |
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return -FDT_ERR_BADSTRUCTURE; |
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path_len = sep - path; |
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name = sep + 1; |
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sep = memchr(name, ':', prop_len); |
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if (*sep != ':') |
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return -FDT_ERR_BADSTRUCTURE; |
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name_len = sep - name; |
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index = strtoul(sep + 1, &endptr, 10); |
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if ((*endptr != '\0') || (endptr <= (sep + 1))) |
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return -FDT_ERR_BADSTRUCTURE; |
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len -= prop_len + 1; |
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value += prop_len + 1; |
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ret = overlay_fixup_one_phandle(fdt, fdto, symbols_off, |
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path, path_len, name, name_len, |
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index, label); |
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if (ret) |
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return ret; |
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} while (len > 0); |
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return 0; |
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} |
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static int overlay_fixup_phandles(void *dt, void *dto) |
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{ |
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int fixups_off, symbols_off; |
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int property; |
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symbols_off = fdt_path_offset(dt, "/__symbols__"); |
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fixups_off = fdt_path_offset(dto, "/__fixups__"); |
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fdt_for_each_property_offset(property, dto, fixups_off) |
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overlay_fixup_phandle(dt, dto, symbols_off, property); |
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return 0; |
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} |
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static int apply_overlay_node(void *dt, int target, |
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void *dto, int fragment) |
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{ |
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int property; |
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int node; |
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fdt_for_each_property_offset(property, dto, fragment) { |
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const char *name; |
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const void *prop; |
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int prop_len; |
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int ret; |
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prop = fdt_getprop_by_offset(dto, property, &name, |
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&prop_len); |
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if (prop_len == -FDT_ERR_NOTFOUND) |
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return -FDT_ERR_INTERNAL; |
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if (prop_len < 0) |
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return prop_len; |
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ret = fdt_setprop(dt, target, name, prop, prop_len); |
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if (ret) |
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return ret; |
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} |
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fdt_for_each_subnode(dto, node, fragment) { |
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const char *name = fdt_get_name(dto, node, NULL); |
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int nnode; |
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int ret; |
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nnode = fdt_add_subnode(dt, target, name); |
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if (nnode == -FDT_ERR_EXISTS) |
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nnode = fdt_subnode_offset(dt, target, name); |
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if (nnode < 0) |
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return nnode; |
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ret = apply_overlay_node(dt, nnode, dto, node); |
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if (ret) |
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return ret; |
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} |
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return 0; |
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} |
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static int overlay_merge(void *dt, void *dto) |
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{ |
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int fragment; |
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fdt_for_each_subnode(dto, fragment, 0) { |
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int overlay; |
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int target; |
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int ret; |
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target = overlay_get_target(dt, dto, fragment); |
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if (target < 0) |
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continue; |
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overlay = fdt_subnode_offset(dto, fragment, "__overlay__"); |
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if (overlay < 0) |
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return overlay; |
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ret = apply_overlay_node(dt, target, dto, overlay); |
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if (ret) |
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return ret; |
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} |
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return 0; |
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} |
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int fdt_overlay_apply(void *fdt, void *fdto) |
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{ |
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uint32_t delta = fdt_get_max_phandle(fdt) + 1; |
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int ret; |
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FDT_CHECK_HEADER(fdt); |
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FDT_CHECK_HEADER(fdto); |
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ret = overlay_adjust_local_phandles(fdto, delta); |
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if (ret) |
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goto err; |
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ret = overlay_update_local_references(fdto, delta); |
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if (ret) |
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goto err; |
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ret = overlay_fixup_phandles(fdt, fdto); |
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if (ret) |
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goto err; |
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ret = overlay_merge(fdt, fdto); |
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if (ret) |
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goto err; |
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/*
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* The overlay has been damaged, erase its magic. |
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*/ |
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fdt_set_magic(fdto, ~0); |
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return 0; |
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err: |
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/*
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* The overlay might have been damaged, erase its magic. |
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*/ |
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fdt_set_magic(fdto, ~0); |
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/*
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* The base device tree might have been damaged, erase its |
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* magic. |
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*/ |
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fdt_set_magic(fdt, ~0); |
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return ret; |
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} |
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