u-boot/include/dm/device-internal.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

93 lines
2.7 KiB
C

/*
* Copyright (C) 2013 Google, Inc
*
* (C) Copyright 2012
* Pavel Herrmann <morpheus.ibis@gmail.com>
* Marek Vasut <marex@denx.de>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#ifndef _DM_DEVICE_INTERNAL_H
#define _DM_DEVICE_INTERNAL_H
struct udevice;
/**
* device_bind() - Create a device and bind it to a driver
*
* Called to set up a new device attached to a driver. The device will either
* have platdata, or a device tree node which can be used to create the
* platdata.
*
* Once bound a device exists but is not yet active until device_probe() is
* called.
*
* @parent: Pointer to device's parent, under which this driver will exist
* @drv: Device's driver
* @name: Name of device (e.g. device tree node name)
* @platdata: Pointer to data for this device - the structure is device-
* specific but may include the device's I/O address, etc.. This is NULL for
* devices which use device tree.
* @of_offset: Offset of device tree node for this device. This is -1 for
* devices which don't use device tree.
* @devp: Returns a pointer to the bound device
* @return 0 if OK, -ve on error
*/
int device_bind(struct udevice *parent, struct driver *drv,
const char *name, void *platdata, int of_offset,
struct udevice **devp);
/**
* device_bind_by_name: Create a device and bind it to a driver
*
* This is a helper function used to bind devices which do not use device
* tree.
*
* @parent: Pointer to device's parent
* @pre_reloc_only: If true, bind the driver only if its DM_INIT_F flag is set.
* If false bind the driver always.
* @info: Name and platdata for this device
* @devp: Returns a pointer to the bound device
* @return 0 if OK, -ve on error
*/
int device_bind_by_name(struct udevice *parent, bool pre_reloc_only,
const struct driver_info *info, struct udevice **devp);
/**
* device_probe() - Probe a device, activating it
*
* Activate a device so that it is ready for use. All its parents are probed
* first.
*
* @dev: Pointer to device to probe
* @return 0 if OK, -ve on error
*/
int device_probe(struct udevice *dev);
/**
* device_remove() - Remove a device, de-activating it
*
* De-activate a device so that it is no longer ready for use. All its
* children are deactivated first.
*
* @dev: Pointer to device to remove
* @return 0 if OK, -ve on error (an error here is normally a very bad thing)
*/
int device_remove(struct udevice *dev);
/**
* device_unbind() - Unbind a device, destroying it
*
* Unbind a device and remove all memory used by it
*
* @dev: Pointer to device to unbind
* @return 0 if OK, -ve on error
*/
int device_unbind(struct udevice *dev);
/* Cast away any volatile pointer */
#define DM_ROOT_NON_CONST (((gd_t *)gd)->dm_root)
#define DM_UCLASS_ROOT_NON_CONST (((gd_t *)gd)->uclass_root)
#endif