87 lines
2.9 KiB
C
87 lines
2.9 KiB
C
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/****************************************************************************
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* drivers/devicetree/fdt.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <stddef.h>
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#include <endian.h>
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#include <errno.h>
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#include <assert.h>
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#include <nuttx/compiler.h>
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#include <nuttx/fdt.h>
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/* Location of the fdt data for this system. */
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static FAR const char *g_fdt_base = NULL;
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: fdt_register
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*
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* Description:
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* Store the pointer to the flattened device tree and verify that it at
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* least appears to be valid. This function will not fully parse the FDT.
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*
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* Return:
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* Return -EINVAL if the fdt header does not have the expected magic value.
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* otherwise return OK. If OK is not returned the existing entry for FDT
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* is not modified.
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*
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****************************************************************************/
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int fdt_register(FAR const char *fdt_base)
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{
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struct fdt_header_s *fdt_header;
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DEBUGASSERT(fdt_base);
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fdt_header = (struct fdt_header_s *)fdt_base;
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if (fdt_header->magic != be32toh(FDT_MAGIC))
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{
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return -EINVAL; /* Bad magic byte read */
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}
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g_fdt_base = fdt_base;
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return OK;
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}
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/****************************************************************************
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* Name: fdt_get
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*
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* Description:
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* Return the pointer to a raw FDT. NULL is returned if no FDT has been
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* loaded.
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*
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****************************************************************************/
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FAR const char *fdt_get(void)
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{
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return g_fdt_base;
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}
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