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00606d7e39
Driver model currently only operates after relocation is complete. In this state U-Boot typically has a small amount of memory available. In adding support for driver model prior to relocation we must try to use as little memory as possible. In addition, on some machines the memory has not be inited and/or the CPU is not running at full speed or the data cache is off. These can reduce execution performance, so the less initialisation that is done before relocation the better. An immediately-obvious improvement is to only initialise drivers which are actually going to be used before relocation. On many boards the only such driver is a serial UART, so this provides a very large potential benefit. Allow drivers to mark themselves as 'pre-reloc' which means that they will be initialised prior to relocation. This can be done either with a driver flag or with a 'dm,pre-reloc' device tree property. To support this, the various dm scanning function now take a 'pre_reloc_only' parameter which indicates that only drivers marked pre-reloc should be bound. Signed-off-by: Simon Glass <sjg@chromium.org>
65 lines
1.5 KiB
C
65 lines
1.5 KiB
C
/*
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* Copyright (c) 2013 Google, Inc
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*
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* (C) Copyright 2012
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* Pavel Herrmann <morpheus.ibis@gmail.com>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#ifndef _DM_ROOT_H_
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#define _DM_ROOT_H_
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struct udevice;
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/**
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* dm_root() - Return pointer to the top of the driver tree
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*
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* This function returns pointer to the root node of the driver tree,
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*
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* @return pointer to root device, or NULL if not inited yet
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*/
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struct udevice *dm_root(void);
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/**
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* dm_scan_platdata() - Scan all platform data and bind drivers
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*
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* This scans all available platdata and creates drivers for each
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*
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* @pre_reloc_only: If true, bind only drivers with the DM_FLAG_PRE_RELOC
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* flag. If false bind all drivers.
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* @return 0 if OK, -ve on error
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*/
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int dm_scan_platdata(bool pre_reloc_only);
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/**
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* dm_scan_fdt() - Scan the device tree and bind drivers
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*
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* This scans the device tree and creates a driver for each node
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*
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* @blob: Pointer to device tree blob
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* @pre_reloc_only: If true, bind only drivers with the DM_FLAG_PRE_RELOC
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* flag. If false bind all drivers.
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* @return 0 if OK, -ve on error
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*/
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int dm_scan_fdt(const void *blob, bool pre_reloc_only);
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/**
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* dm_init() - Initialise Driver Model structures
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*
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* This function will initialize roots of driver tree and class tree.
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* This needs to be called before anything uses the DM
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*
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* @return 0 if OK, -ve on error
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*/
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int dm_init(void);
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/**
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* dm_uninit - Uninitialise Driver Model structures
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*
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* All devices will be removed and unbound
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* @return 0 if OK, -ve on error
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*/
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int dm_uninit(void);
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#endif
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