u-boot/include/dm/lists.h
Simon Glass 00606d7e39 dm: Allow drivers to be marked 'before relocation'
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>
2014-07-23 14:07:24 +01:00

59 lines
1.6 KiB
C

/*
* Copyright (c) 2013 Google, Inc
*
* (C) Copyright 2012
* Pavel Herrmann <morpheus.ibis@gmail.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#ifndef _DM_LISTS_H_
#define _DM_LISTS_H_
#include <dm/uclass-id.h>
/**
* lists_driver_lookup_name() - Return u_boot_driver corresponding to name
*
* This function returns a pointer to a driver given its name. This is used
* for binding a driver given its name and platdata.
*
* @name: Name of driver to look up
* @return pointer to driver, or NULL if not found
*/
struct driver *lists_driver_lookup_name(const char *name);
/**
* lists_uclass_lookup() - Return uclass_driver based on ID of the class
* id: ID of the class
*
* This function returns the pointer to uclass_driver, which is the class's
* base structure based on the ID of the class. Returns NULL on error.
*/
struct uclass_driver *lists_uclass_lookup(enum uclass_id id);
/**
* lists_bind_drivers() - search for and bind all drivers to parent
*
* This searches the U_BOOT_DEVICE() structures and creates new devices for
* each one. The devices will have @parent as their parent.
*
* @parent: parent driver (root)
* @early_only: If true, bind only drivers with the DM_INIT_F flag. If false
* bind all drivers.
*/
int lists_bind_drivers(struct udevice *parent, bool pre_reloc_only);
/**
* lists_bind_fdt() - bind a device tree node
*
* This creates a new device bound to the given device tree node, with
* @parent as its parent.
*
* @parent: parent driver (root)
* @blob: device tree blob
* @offset: offset of this device tree node
*/
int lists_bind_fdt(struct udevice *parent, const void *blob, int offset);
#endif