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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>
118 lines
2.1 KiB
C
118 lines
2.1 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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#include <common.h>
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#include <errno.h>
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#include <malloc.h>
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#include <libfdt.h>
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#include <dm/device.h>
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#include <dm/device-internal.h>
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#include <dm/lists.h>
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#include <dm/platdata.h>
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#include <dm/root.h>
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#include <dm/uclass.h>
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#include <dm/util.h>
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#include <linux/list.h>
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DECLARE_GLOBAL_DATA_PTR;
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static const struct driver_info root_info = {
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.name = "root_driver",
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};
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struct udevice *dm_root(void)
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{
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if (!gd->dm_root) {
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dm_warn("Virtual root driver does not exist!\n");
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return NULL;
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}
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return gd->dm_root;
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}
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int dm_init(void)
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{
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int ret;
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if (gd->dm_root) {
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dm_warn("Virtual root driver already exists!\n");
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return -EINVAL;
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}
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INIT_LIST_HEAD(&DM_UCLASS_ROOT_NON_CONST);
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ret = device_bind_by_name(NULL, false, &root_info, &DM_ROOT_NON_CONST);
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if (ret)
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return ret;
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ret = device_probe(DM_ROOT_NON_CONST);
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if (ret)
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return ret;
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return 0;
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}
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int dm_uninit(void)
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{
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device_remove(dm_root());
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device_unbind(dm_root());
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return 0;
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}
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int dm_scan_platdata(bool pre_reloc_only)
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{
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int ret;
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ret = lists_bind_drivers(DM_ROOT_NON_CONST, pre_reloc_only);
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if (ret == -ENOENT) {
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dm_warn("Some drivers were not found\n");
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ret = 0;
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}
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if (ret)
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return ret;
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return 0;
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}
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#ifdef CONFIG_OF_CONTROL
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int dm_scan_fdt(const void *blob, bool pre_reloc_only)
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{
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int offset = 0;
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int ret = 0, err;
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int depth = 0;
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do {
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offset = fdt_next_node(blob, offset, &depth);
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if (offset > 0 && depth == 1) {
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if (pre_reloc_only &&
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!fdt_getprop(blob, offset, "u-boot,dm-pre-reloc", NULL))
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continue;
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err = lists_bind_fdt(gd->dm_root, blob, offset);
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if (err && !ret)
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ret = err;
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}
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} while (offset > 0);
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if (ret)
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dm_warn("Some drivers failed to bind\n");
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return ret;
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}
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#endif
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/* This is the root driver - all drivers are children of this */
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U_BOOT_DRIVER(root_driver) = {
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.name = "root_driver",
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.id = UCLASS_ROOT,
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};
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/* This is the root uclass */
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UCLASS_DRIVER(root) = {
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.name = "root",
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.id = UCLASS_ROOT,
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};
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