U-Boot

// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright 2021 Google LLC
 * Written by Simon Glass <sjg@chromium.org>
 */

#define LOG_CATEGORY UCLASS_BOOTSTD

#include <common.h>
#include <bootdev.h>
#include <bootflow.h>
#include <bootmeth.h>
#include <bootstd.h>
#include <dm.h>
#include <malloc.h>
#include <dm/device-internal.h>
#include <dm/uclass-internal.h>

/* error codes used to signal running out of things */
enum {
	BF_NO_MORE_PARTS	= -ESHUTDOWN,
	BF_NO_MORE_DEVICES	= -ENODEV,
};

/**
 * bootflow_state - name for each state
 *
 * See enum bootflow_state_t for what each of these means
 */
static const char *const bootflow_state[BOOTFLOWST_COUNT] = {
	"base",
	"media",
	"part",
	"fs",
	"file",
	"ready",
};

const char *bootflow_state_get_name(enum bootflow_state_t state)
{
	/* This doesn't need to be a useful name, since it will never occur */
	if (state < 0 || state >= BOOTFLOWST_COUNT)
		return "?";

	return bootflow_state[state];
}

int bootflow_first_glob(struct bootflow **bflowp)
{
	struct bootstd_priv *std;
	int ret;

	ret = bootstd_get_priv(&std);
	if (ret)
		return ret;

	if (list_empty(&std->glob_head))
		return -ENOENT;

	*bflowp = list_first_entry(&std->glob_head, struct bootflow,
				   glob_node);

	return 0;
}

int bootflow_next_glob(struct bootflow **bflowp)
{
	struct bootstd_priv *std;
	struct bootflow *bflow = *bflowp;
	int ret;

	ret = bootstd_get_priv(&std);
	if (ret)
		return ret;

	*bflowp = NULL;

	if (list_is_last(&bflow->glob_node, &std->glob_head))
		return -ENOENT;

	*bflowp = list_entry(bflow->glob_node.next, struct bootflow, glob_node);

	return 0;
}

void bootflow_iter_init(struct bootflow_iter *iter, int flags)
{
	memset(iter, '\0', sizeof(*iter));
	iter->first_glob_method = -1;
	iter->flags = flags;
}

void bootflow_iter_uninit(struct bootflow_iter *iter)
{
	free(iter->dev_order);
	free(iter->method_order);
}

int bootflow_iter_drop_bootmeth(struct bootflow_iter *iter,
				const struct udevice *bmeth)
{
	/* We only support disabling the current bootmeth */
	if (bmeth != iter->method || iter->cur_method >= iter->num_methods ||
	    iter->method_order[iter->cur_method] != bmeth)
		return -EINVAL;

	memmove(&iter->method_order[iter->cur_method],
		&iter->method_order[iter->cur_method + 1],
		(iter->num_methods - iter->cur_method - 1) * sizeof(void *));

	iter->num_methods--;

	return 0;
}

static void bootflow_iter_set_dev(struct bootflow_iter *iter,
				  struct udevice *dev)
{
	struct bootmeth_uc_plat *ucp = dev_get_uclass_plat(iter->method);

	iter->dev = dev;
	if ((iter->flags & (BOOTFLOWF_SHOW | BOOTFLOWF_SINGLE_DEV)) ==
	    BOOTFLOWF_SHOW) {
		if (dev)
			printf("Scanning bootdev '%s':\n", dev->name);
		else if (IS_ENABLED(CONFIG_BOOTMETH_GLOBAL) &&
			 ucp->flags & BOOTMETHF_GLOBAL)
			printf("Scanning global bootmeth '%s':\n",
			       iter->method->name);
		else
			printf("No more bootdevs\n");
	}
}

/**
 * iter_incr() - Move to the next item (method, part, bootdev)
 *
 * Return: 0 if OK, BF_NO_MORE_DEVICES if there are no more bootdevs
 */
static int iter_incr(struct bootflow_iter *iter)
{
	struct udevice *dev;
	bool inc_dev = true;
	bool global;
	int ret;

	global = iter->doing_global;

	if (iter->err == BF_NO_MORE_DEVICES)
		return BF_NO_MORE_DEVICES;

	if (iter->err != BF_NO_MORE_PARTS) {
		/* Get the next boothmethod */
		if (++iter->cur_method < iter->num_methods) {
			iter->method = iter->method_order[iter->cur_method];
			return 0;
		}

		/*
		 * If we have finished scanning the global bootmeths, start the
		 * normal bootdev scan
		 */
		if (IS_ENABLED(CONFIG_BOOTMETH_GLOBAL) && global) {
			iter->num_methods = iter->first_glob_method;
			iter->doing_global = false;

			/*
			 * Don't move to the next dev as we haven't tried this
			 * one yet!
			 */
			inc_dev = false;
		}
	}

	/* No more bootmeths; start at the first one, and... */
	iter->cur_method = 0;
	iter->method = iter->method_order[iter->cur_method];

	if (iter->err != BF_NO_MORE_PARTS) {
		/* ...select next partition  */
		if (++iter->part <= iter->max_part)
			return 0;
	}

	/* No more partitions; start at the first one and...*/
	iter->part = 0;

	/*
	 * Note: as far as we know, there is no partition table on the next
	 * bootdev, so set max_part to 0 until we discover otherwise. See
	 * bootdev_find_in_blk() for where this is set.
	 */
	iter->max_part = 0;

	/* ...select next bootdev */
	if (iter->flags & BOOTFLOWF_SINGLE_DEV) {
		ret = -ENOENT;
	} else {
		if (inc_dev)
			iter->cur_dev++;
		if (iter->cur_dev == iter->num_devs) {
			ret = -ENOENT;
			bootflow_iter_set_dev(iter, NULL);
		} else {
			dev = iter->dev_order[iter->cur_dev];
			ret = device_probe(dev);
			if (!log_msg_ret("probe", ret))
				bootflow_iter_set_dev(iter, dev);
		}
	}

	/* if there are no more bootdevs, give up */
	if (ret)
		return log_msg_ret("incr", BF_NO_MORE_DEVICES);

	return 0;
}

/**
 * bootflow_check() - Check if a bootflow can be obtained
 *
 * @iter: Provides part, bootmeth to use
 * @bflow: Bootflow to update on success
 * Return: 0 if OK, -ENOSYS if there is no bootflow support on this device,
 *	BF_NO_MORE_PARTS if there are no more partitions on bootdev
 */
static int bootflow_check(struct bootflow_iter *iter, struct bootflow *bflow)
{
	struct udevice *dev;
	int ret;

	if (IS_ENABLED(CONFIG_BOOTMETH_GLOBAL) && iter->doing_global) {
		bootflow_iter_set_dev(iter, NULL);
		ret = bootmeth_get_bootflow(iter->method, bflow);
		if (ret)
			return log_msg_ret("glob", ret);

		return 0;
	}

	dev = iter->dev;
	ret = bootdev_get_bootflow(dev, iter, bflow);

	/* If we got a valid bootflow, return it */
	if (!ret) {
		log_debug("Bootdevice '%s' part %d method '%s': Found bootflow\n",
			  dev->name, iter->part, iter->method->name);
		return 0;
	}

	/* Unless there is nothing more to try, move to the next device */
	else if (ret != BF_NO_MORE_PARTS && ret != -ENOSYS) {
		log_debug("Bootdevice '%s' part %d method '%s': Error %d\n",
			  dev->name, iter->part, iter->method->name, ret);
		/*
		 * For 'all' we return all bootflows, even
		 * those with errors
		 */
		if (iter->flags & BOOTFLOWF_ALL)
			return log_msg_ret("all", ret);
	}
	if (ret)
		return log_msg_ret("check", ret);

	return 0;
}

int bootflow_scan_bootdev(struct udevice *dev, struct bootflow_iter *iter,
			  int flags, struct bootflow *bflow)
{
	int ret;

	if (dev)
		flags |= BOOTFLOWF_SKIP_GLOBAL;
	bootflow_iter_init(iter, flags);

	ret = bootdev_setup_iter_order(iter, &dev);
	if (ret)
		return log_msg_ret("obdev", -ENODEV);

	ret = bootmeth_setup_iter_order(iter, !(flags & BOOTFLOWF_SKIP_GLOBAL));
	if (ret)
		return log_msg_ret("obmeth", -ENODEV);

	/* Find the first bootmeth (there must be at least one!) */
	iter->method = iter->method_order[iter->cur_method];
	if (!IS_ENABLED(CONFIG_BOOTMETH_GLOBAL) || !iter->doing_global)
		bootflow_iter_set_dev(iter, dev);

	ret = bootflow_check(iter, bflow);
	if (ret) {
		if (ret != BF_NO_MORE_PARTS && ret != -ENOSYS) {
			if (iter->flags & BOOTFLOWF_ALL)
				return log_msg_ret("all", ret);
		}
		iter->err = ret;
		ret = bootflow_scan_next(iter, bflow);
		if (ret)
			return log_msg_ret("get", ret);
	}

	return 0;
}

int bootflow_scan_first(struct bootflow_iter *iter, int flags,
			struct bootflow *bflow)
{
	int ret;

	ret = bootflow_scan_bootdev(NULL, iter, flags, bflow);
	if (ret)
		return log_msg_ret("start", ret);

	return 0;
}

int bootflow_scan_next(struct bootflow_iter *iter, struct bootflow *bflow)
{
	int ret;

	do {
		ret = iter_incr(iter);
		if (ret == BF_NO_MORE_DEVICES)
			return log_msg_ret("done", ret);

		if (!ret) {
			ret = bootflow_check(iter, bflow);
			if (!ret)
				return 0;
			iter->err = ret;
			if (ret != BF_NO_MORE_PARTS && ret != -ENOSYS) {
				if (iter->flags & BOOTFLOWF_ALL)
					return log_msg_ret("all", ret);
			}
		} else {
			iter->err = ret;
		}

	} while (1);
}

void bootflow_init(struct bootflow *bflow, struct udevice *bootdev,
		   struct udevice *meth)
{
	memset(bflow, '\0', sizeof(*bflow));
	bflow->dev = bootdev;
	bflow->method = meth;
	bflow->state = BOOTFLOWST_BASE;
}

void bootflow_free(struct bootflow *bflow)
{
	free(bflow->name);
	free(bflow->subdir);
	free(bflow->fname);
	free(bflow->buf);
}

void bootflow_remove(struct bootflow *bflow)
{
	if (bflow->dev)
		list_del(&bflow->bm_node);
	list_del(&bflow->glob_node);

	bootflow_free(bflow);
	free(bflow);
}

int bootflow_boot(struct bootflow *bflow)
{
	int ret;

	if (bflow->state != BOOTFLOWST_READY)
		return log_msg_ret("load", -EPROTO);

	ret = bootmeth_boot(bflow->method, bflow);
	if (ret)
		return log_msg_ret("boot", ret);

	/*
	 * internal error, should not get here since we should have booted
	 * something or returned an error
	 */

	return log_msg_ret("end", -EFAULT);
}

int bootflow_run_boot(struct bootflow_iter *iter, struct bootflow *bflow)
{
	int ret;

	printf("** Booting bootflow '%s' with %s\n", bflow->name,
	       bflow->method->name);
	ret = bootflow_boot(bflow);
	if (!IS_ENABLED(CONFIG_BOOTSTD_FULL)) {
		printf("Boot failed (err=%d)\n", ret);
		return ret;
	}

	switch (ret) {
	case -EPROTO:
		printf("Bootflow not loaded (state '%s')\n",
		       bootflow_state_get_name(bflow->state));
		break;
	case -ENOSYS:
		printf("Boot method '%s' not supported\n", bflow->method->name);
		break;
	case -ENOTSUPP:
		/* Disable this bootflow for this iteration */
		if (iter) {
			int ret2;

			ret2 = bootflow_iter_drop_bootmeth(iter, bflow->method);
			if (!ret2) {
				printf("Boot method '%s' failed and will not be retried\n",
				       bflow->method->name);
			}
		}

		break;
	default:
		printf("Boot failed (err=%d)\n", ret);
		break;
	}

	return ret;
}

int bootflow_iter_uses_blk_dev(const struct bootflow_iter *iter)
{
	const struct udevice *media = dev_get_parent(iter->dev);
	enum uclass_id id = device_get_uclass_id(media);

	log_debug("uclass %d: %s\n", id, uclass_get_name(id));
	if (id != UCLASS_ETH && id != UCLASS_BOOTSTD)
		return 0;

	return -ENOTSUPP;
}

int bootflow_iter_uses_network(const struct bootflow_iter *iter)
{
	const struct udevice *media = dev_get_parent(iter->dev);
	enum uclass_id id = device_get_uclass_id(media);

	log_debug("uclass %d: %s\n", id, uclass_get_name(id));
	if (id == UCLASS_ETH)
		return 0;

	return -ENOTSUPP;
}

int bootflow_iter_uses_system(const struct bootflow_iter *iter)
{
	const struct udevice *media = dev_get_parent(iter->dev);
	enum uclass_id id = device_get_uclass_id(media);

	log_debug("uclass %d: %s\n", id, uclass_get_name(id));
	if (id == UCLASS_BOOTSTD)
		return 0;

	return -ENOTSUPP;
}