/* * Copyright (c) 2018-2020, ARM Limited and Contributors. All rights reserved. * * SPDX-License-Identifier: BSD-3-Clause */ /* Helper functions to offer easier navigation of Device Tree Blob */ #include #include #include #include #include /* * Read cells from a given property of the given node. Any number of 32-bit * cells of the property can be read. Returns 0 on success, or a negative * FDT error value otherwise. */ int fdt_read_uint32_array(const void *dtb, int node, const char *prop_name, unsigned int cells, uint32_t *value) { const fdt32_t *prop; int value_len; assert(dtb != NULL); assert(prop_name != NULL); assert(value != NULL); assert(node >= 0); /* Access property and obtain its length (in bytes) */ prop = fdt_getprop(dtb, node, prop_name, &value_len); if (prop == NULL) { WARN("Couldn't find property %s in dtb\n", prop_name); return -FDT_ERR_NOTFOUND; } /* Verify that property length can fill the entire array. */ if (NCELLS((unsigned int)value_len) < cells) { WARN("Property length mismatch\n"); return -FDT_ERR_BADVALUE; } for (unsigned int i = 0U; i < cells; i++) { value[i] = fdt32_to_cpu(prop[i]); } return 0; } int fdt_read_uint32(const void *dtb, int node, const char *prop_name, uint32_t *value) { return fdt_read_uint32_array(dtb, node, prop_name, 1, value); } int fdt_read_uint64(const void *dtb, int node, const char *prop_name, uint64_t *value) { uint32_t array[2] = {0, 0}; int ret; ret = fdt_read_uint32_array(dtb, node, prop_name, 2, array); if (ret < 0) { return ret; } *value = ((uint64_t)array[0] << 32) | array[1]; return 0; } /* * Read bytes from a given property of the given node. Any number of * bytes of the property can be read. The fdt pointer is updated. * Returns 0 on success, and -1 on error. */ int fdtw_read_bytes(const void *dtb, int node, const char *prop, unsigned int length, void *value) { const void *ptr; int value_len; assert(dtb != NULL); assert(prop != NULL); assert(value != NULL); assert(node >= 0); /* Access property and obtain its length (in bytes) */ ptr = fdt_getprop_namelen(dtb, node, prop, (int)strlen(prop), &value_len); if (ptr == NULL) { WARN("Couldn't find property %s in dtb\n", prop); return -1; } /* Verify that property length is not less than number of bytes */ if ((unsigned int)value_len < length) { WARN("Property length mismatch\n"); return -1; } (void)memcpy(value, ptr, length); return 0; } /* * Read string from a given property of the given node. Up to 'size - 1' * characters are read, and a NUL terminator is added. Returns 0 on success, * and -1 upon error. */ int fdtw_read_string(const void *dtb, int node, const char *prop, char *str, size_t size) { const char *ptr; size_t len; assert(dtb != NULL); assert(node >= 0); assert(prop != NULL); assert(str != NULL); assert(size > 0U); ptr = fdt_getprop_namelen(dtb, node, prop, (int)strlen(prop), NULL); if (ptr == NULL) { WARN("Couldn't find property %s in dtb\n", prop); return -1; } len = strlcpy(str, ptr, size); if (len >= size) { WARN("String of property %s in dtb has been truncated\n", prop); return -1; } return 0; } /* * Write cells in place to a given property of the given node. At most 2 cells * of the property are written. Returns 0 on success, and -1 upon error. */ int fdtw_write_inplace_cells(void *dtb, int node, const char *prop, unsigned int cells, void *value) { int err, len; assert(dtb != NULL); assert(prop != NULL); assert(value != NULL); assert(node >= 0); /* We expect either 1 or 2 cell property */ assert(cells <= 2U); if (cells == 2U) *(uint64_t *)value = cpu_to_fdt64(*(uint64_t *)value); else *(uint32_t *)value = cpu_to_fdt32(*(uint32_t *)value); len = (int)cells * 4; /* Set property value in place */ err = fdt_setprop_inplace(dtb, node, prop, value, len); if (err != 0) { WARN("Modify property %s failed with error %d\n", prop, err); return -1; } return 0; } /* * Write bytes in place to a given property of the given node. * Any number of bytes of the property can be written. * Returns 0 on success, and < 0 on error. */ int fdtw_write_inplace_bytes(void *dtb, int node, const char *prop, unsigned int length, const void *data) { const void *ptr; int namelen, value_len, err; assert(dtb != NULL); assert(prop != NULL); assert(data != NULL); assert(node >= 0); namelen = (int)strlen(prop); /* Access property and obtain its length in bytes */ ptr = fdt_getprop_namelen(dtb, node, prop, namelen, &value_len); if (ptr == NULL) { WARN("Couldn't find property %s in dtb\n", prop); return -1; } /* Verify that property length is not less than number of bytes */ if ((unsigned int)value_len < length) { WARN("Property length mismatch\n"); return -1; } /* Set property value in place */ err = fdt_setprop_inplace_namelen_partial(dtb, node, prop, namelen, 0, data, (int)length); if (err != 0) { WARN("Set property %s failed with error %d\n", prop, err); } return err; }