bootstd: Add the bootdev uclass

A 'bootdev' is a device which can be used to boot an operating system.
It is a child of the media device (e.g. MMC) which handles reading files
from that device, such as a bootflow file.

Add a uclass for bootdev and the various helpers needed to make it
work. Also add a binding file, empty for now.

Signed-off-by: Simon Glass <sjg@chromium.org>

2 files changed, 641 insertions, 0 deletions

diff --git a/boot/Makefile b/boot/Makefile
index 21dcf6a605..301d75fb64 100644
--- a/boot/Makefile
+++ b/boot/Makefile
@@ -19,6 +19,7 @@ obj-y += image.o image-board.o
 obj-$(CONFIG_ANDROID_AB) += android_ab.o
 obj-$(CONFIG_ANDROID_BOOT_IMAGE) += image-android.o image-android-dt.o
 
+obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += bootdev-uclass.o
 obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += bootstd-uclass.o
 
 obj-$(CONFIG_$(SPL_TPL_)OF_LIBFDT) += image-fdt.o
diff --git a/boot/bootdev-uclass.c b/boot/bootdev-uclass.c
new file mode 100644
index 0000000000..e0baeb82b1
--- /dev/null
+++ b/boot/bootdev-uclass.c
@@ -0,0 +1,640 @@
+// 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 <dm.h>
+#include <bootdev.h>
+#include <bootflow.h>
+#include <bootstd.h>
+#include <env.h>
+#include <fs.h>
+#include <log.h>
+#include <malloc.h>
+#include <part.h>
+#include <sort.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <dm/uclass-internal.h>
+
+enum {
+	/*
+	 * Set some sort of limit on the number of partitions a bootdev can
+	 * have. Note that for disks this limits the partitions numbers that
+	 * are scanned to 1..MAX_BOOTFLOWS_PER_BOOTDEV
+	 */
+	MAX_PART_PER_BOOTDEV	= 30,
+
+	/* Maximum supported length of the "boot_targets" env string */
+	BOOT_TARGETS_MAX_LEN	= 100,
+};
+
+int bootdev_add_bootflow(struct bootflow *bflow)
+{
+	struct bootdev_uc_plat *ucp = dev_get_uclass_plat(bflow->dev);
+	struct bootstd_priv *std;
+	struct bootflow *new;
+	int ret;
+
+	assert(bflow->dev);
+	ret = bootstd_get_priv(&std);
+	if (ret)
+		return ret;
+
+	new = malloc(sizeof(*bflow));
+	if (!new)
+		return log_msg_ret("bflow", -ENOMEM);
+	memcpy(new, bflow, sizeof(*bflow));
+
+	list_add_tail(&new->glob_node, &std->glob_head);
+	list_add_tail(&new->bm_node, &ucp->bootflow_head);
+
+	return 0;
+}
+
+int bootdev_first_bootflow(struct udevice *dev, struct bootflow **bflowp)
+{
+	struct bootdev_uc_plat *ucp = dev_get_uclass_plat(dev);
+
+	if (list_empty(&ucp->bootflow_head))
+		return -ENOENT;
+
+	*bflowp = list_first_entry(&ucp->bootflow_head, struct bootflow,
+				   bm_node);
+
+	return 0;
+}
+
+int bootdev_next_bootflow(struct bootflow **bflowp)
+{
+	struct bootflow *bflow = *bflowp;
+	struct bootdev_uc_plat *ucp = dev_get_uclass_plat(bflow->dev);
+
+	*bflowp = NULL;
+
+	if (list_is_last(&bflow->bm_node, &ucp->bootflow_head))
+		return -ENOENT;
+
+	*bflowp = list_entry(bflow->bm_node.next, struct bootflow, bm_node);
+
+	return 0;
+}
+
+int bootdev_bind(struct udevice *parent, const char *drv_name, const char *name,
+		 struct udevice **devp)
+{
+	struct udevice *dev;
+	char dev_name[30];
+	char *str;
+	int ret;
+
+	snprintf(dev_name, sizeof(dev_name), "%s.%s", parent->name, name);
+	str = strdup(dev_name);
+	if (!str)
+		return -ENOMEM;
+	ret = device_bind_driver(parent, drv_name, str, &dev);
+	if (ret)
+		return ret;
+	device_set_name_alloced(dev);
+	*devp = dev;
+
+	return 0;
+}
+
+int bootdev_find_in_blk(struct udevice *dev, struct udevice *blk,
+			struct bootflow_iter *iter, struct bootflow *bflow)
+{
+	struct blk_desc *desc = dev_get_uclass_plat(blk);
+	struct disk_partition info;
+	char partstr[20];
+	char name[60];
+	int ret;
+
+	/* Sanity check */
+	if (iter->part >= MAX_PART_PER_BOOTDEV)
+		return log_msg_ret("max", -ESHUTDOWN);
+
+	bflow->blk = blk;
+	if (iter->part)
+		snprintf(partstr, sizeof(partstr), "part_%x", iter->part);
+	else
+		strcpy(partstr, "whole");
+	snprintf(name, sizeof(name), "%s.%s", dev->name, partstr);
+	bflow->name = strdup(name);
+	if (!bflow->name)
+		return log_msg_ret("name", -ENOMEM);
+
+	bflow->part = iter->part;
+
+	/*
+	 * partition numbers start at 0 so this cannot succeed, but it can tell
+	 * us whether there is valid media there
+	 */
+	ret = part_get_info(desc, iter->part, &info);
+	if (!iter->part && ret == -ENOENT)
+		ret = 0;
+
+	/*
+	 * This error indicates the media is not present. Otherwise we just
+	 * blindly scan the next partition. We could be more intelligent here
+	 * and check which partition numbers actually exist.
+	 */
+	if (ret == -EOPNOTSUPP)
+		ret = -ESHUTDOWN;
+	else
+		bflow->state = BOOTFLOWST_MEDIA;
+	if (ret)
+		return log_msg_ret("part", ret);
+
+	/*
+	 * Currently we don't get the number of partitions, so just
+	 * assume a large number
+	 */
+	iter->max_part = MAX_PART_PER_BOOTDEV;
+
+	if (iter->part) {
+		ret = fs_set_blk_dev_with_part(desc, bflow->part);
+		bflow->state = BOOTFLOWST_PART;
+
+		/* Use an #ifdef due to info.sys_ind */
+#ifdef CONFIG_DOS_PARTITION
+		log_debug("%s: Found partition %x type %x fstype %d\n",
+			  blk->name, bflow->part, info.sys_ind,
+			  ret ? -1 : fs_get_type());
+#endif
+		if (ret)
+			return log_msg_ret("fs", ret);
+		bflow->state = BOOTFLOWST_FS;
+	}
+
+	return 0;
+}
+
+void bootdev_list(bool probe)
+{
+	struct udevice *dev;
+	int ret;
+	int i;
+
+	printf("Seq  Probed  Status  Uclass    Name\n");
+	printf("---  ------  ------  --------  ------------------\n");
+	if (probe)
+		ret = uclass_first_device_err(UCLASS_BOOTDEV, &dev);
+	else
+		ret = uclass_find_first_device(UCLASS_BOOTDEV, &dev);
+	for (i = 0; dev; i++) {
+		printf("%3x   [ %c ]  %6s  %-9.9s %s\n", dev_seq(dev),
+		       device_active(dev) ? '+' : ' ',
+		       ret ? simple_itoa(ret) : "OK",
+		       dev_get_uclass_name(dev_get_parent(dev)), dev->name);
+		if (probe)
+			ret = uclass_next_device_err(&dev);
+		else
+			ret = uclass_find_next_device(&dev);
+	}
+	printf("---  ------  ------  --------  ------------------\n");
+	printf("(%d bootdev%s)\n", i, i != 1 ? "s" : "");
+}
+
+int bootdev_setup_for_dev(struct udevice *parent, const char *drv_name)
+{
+	struct udevice *bdev;
+	int ret;
+
+	ret = device_find_first_child_by_uclass(parent, UCLASS_BOOTDEV,
+						&bdev);
+	if (ret) {
+		if (ret != -ENODEV) {
+			log_debug("Cannot access bootdev device\n");
+			return ret;
+		}
+
+		ret = bootdev_bind(parent, drv_name, "bootdev", &bdev);
+		if (ret) {
+			log_debug("Cannot create bootdev device\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+int bootdev_setup_sibling_blk(struct udevice *blk, const char *drv_name)
+{
+	struct udevice *parent, *dev;
+	char dev_name[50];
+	int ret;
+
+	snprintf(dev_name, sizeof(dev_name), "%s.%s", blk->name, "bootdev");
+
+	parent = dev_get_parent(blk);
+	ret = device_find_child_by_name(parent, dev_name, &dev);
+	if (ret) {
+		char *str;
+
+		if (ret != -ENODEV) {
+			log_debug("Cannot access bootdev device\n");
+			return ret;
+		}
+		str = strdup(dev_name);
+		if (!str)
+			return -ENOMEM;
+
+		ret = device_bind_driver(parent, drv_name, str, &dev);
+		if (ret) {
+			log_debug("Cannot create bootdev device\n");
+			return ret;
+		}
+		device_set_name_alloced(dev);
+	}
+
+	return 0;
+}
+
+int bootdev_get_sibling_blk(struct udevice *dev, struct udevice **blkp)
+{
+	struct udevice *parent = dev_get_parent(dev);
+	struct udevice *blk;
+	int ret, len;
+	char *p;
+
+	if (device_get_uclass_id(dev) != UCLASS_BOOTDEV)
+		return -EINVAL;
+
+	/* This should always work if bootdev_setup_sibling_blk() was used */
+	p = strstr(dev->name, ".bootdev");
+	if (!p)
+		return log_msg_ret("str", -EINVAL);
+
+	len = p - dev->name;
+	ret = device_find_child_by_namelen(parent, dev->name, len, &blk);
+	if (ret)
+		return log_msg_ret("find", ret);
+	*blkp = blk;
+
+	return 0;
+}
+
+static int bootdev_get_from_blk(struct udevice *blk, struct udevice **bootdevp)
+{
+	struct udevice *parent = dev_get_parent(blk);
+	struct udevice *bootdev;
+	char dev_name[50];
+	int ret;
+
+	if (device_get_uclass_id(blk) != UCLASS_BLK)
+		return -EINVAL;
+
+	/* This should always work if bootdev_setup_sibling_blk() was used */
+	snprintf(dev_name, sizeof(dev_name), "%s.%s", blk->name, "bootdev");
+	ret = device_find_child_by_name(parent, dev_name, &bootdev);
+	if (ret)
+		return log_msg_ret("find", ret);
+	*bootdevp = bootdev;
+
+	return 0;
+}
+
+int bootdev_unbind_dev(struct udevice *parent)
+{
+	struct udevice *dev;
+	int ret;
+
+	ret = device_find_first_child_by_uclass(parent, UCLASS_BOOTDEV, &dev);
+	if (!ret) {
+		ret = device_remove(dev, DM_REMOVE_NORMAL);
+		if (ret)
+			return log_msg_ret("rem", ret);
+		ret = device_unbind(dev);
+		if (ret)
+			return log_msg_ret("unb", ret);
+	}
+
+	return 0;
+}
+
+/**
+ * bootdev_find_by_label() - Convert a label string to a bootdev device
+ *
+ * Looks up a label name to find the associated bootdev. For example, if the
+ * label name is "mmc2", this will find a bootdev for an mmc device whose
+ * sequence number is 2.
+ *
+ * @label: Label string to convert, e.g. "mmc2"
+ * @devp: Returns bootdev device corresponding to that boot label
+ * Return: 0 if OK, -EINVAL if the label name (e.g. "mmc") does not refer to a
+ *	uclass, -ENOENT if no bootdev for that media has the sequence number
+ *	(e.g. 2)
+ */
+int bootdev_find_by_label(const char *label, struct udevice **devp)
+{
+	struct udevice *media;
+	struct uclass *uc;
+	enum uclass_id id;
+	const char *end;
+	int seq;
+
+	seq = trailing_strtoln_end(label, NULL, &end);
+	id = uclass_get_by_namelen(label, end - label);
+	log_debug("find %s: seq=%d, id=%d/%s\n", label, seq, id,
+		  uclass_get_name(id));
+	if (id == UCLASS_INVALID) {
+		log_warning("Unknown uclass '%s' in label\n", label);
+		return -EINVAL;
+	}
+	if (id == UCLASS_USB)
+		id = UCLASS_MASS_STORAGE;
+
+	/* Iterate through devices in the media uclass (e.g. UCLASS_MMC) */
+	uclass_id_foreach_dev(id, media, uc) {
+		struct udevice *bdev, *blk;
+		int ret;
+
+		/* if there is no seq, match anything */
+		if (seq != -1 && dev_seq(media) != seq) {
+			log_debug("- skip, media seq=%d\n", dev_seq(media));
+			continue;
+		}
+
+		ret = device_find_first_child_by_uclass(media, UCLASS_BOOTDEV,
+							&bdev);
+		if (ret) {
+			log_debug("- looking via blk, seq=%d, id=%d\n", seq,
+				  id);
+			ret = blk_find_device(id, seq, &blk);
+			if (!ret) {
+				log_debug("- get from blk %s\n", blk->name);
+				ret = bootdev_get_from_blk(blk, &bdev);
+			}
+		}
+		if (!ret) {
+			log_debug("- found %s\n", bdev->name);
+			*devp = bdev;
+			return 0;
+		}
+		log_debug("- no device in %s\n", media->name);
+	}
+	log_warning("Unknown seq %d for label '%s'\n", seq, label);
+
+	return -ENOENT;
+}
+
+int bootdev_find_by_any(const char *name, struct udevice **devp)
+{
+	struct udevice *dev;
+	int ret, seq;
+	char *endp;
+
+	seq = simple_strtol(name, &endp, 16);
+
+	/* Select by name, label or number */
+	if (*endp) {
+		ret = uclass_get_device_by_name(UCLASS_BOOTDEV, name, &dev);
+		if (ret == -ENODEV) {
+			ret = bootdev_find_by_label(name, &dev);
+			if (ret) {
+				printf("Cannot find bootdev '%s' (err=%d)\n",
+				       name, ret);
+				return ret;
+			}
+			ret = device_probe(dev);
+		}
+		if (ret) {
+			printf("Cannot probe bootdev '%s' (err=%d)\n", name,
+			       ret);
+			return ret;
+		}
+	} else {
+		ret = uclass_get_device_by_seq(UCLASS_BOOTDEV, seq, &dev);
+	}
+	if (ret) {
+		printf("Cannot find '%s' (err=%d)\n", name, ret);
+		return ret;
+	}
+
+	*devp = dev;
+
+	return 0;
+}
+
+int bootdev_get_bootflow(struct udevice *dev, struct bootflow_iter *iter,
+			 struct bootflow *bflow)
+{
+	const struct bootdev_ops *ops = bootdev_get_ops(dev);
+
+	if (!ops->get_bootflow)
+		return -ENOSYS;
+	memset(bflow, '\0', sizeof(*bflow));
+	bflow->dev = dev;
+	bflow->method = iter->method;
+	bflow->state = BOOTFLOWST_BASE;
+
+	return ops->get_bootflow(dev, iter, bflow);
+}
+
+void bootdev_clear_bootflows(struct udevice *dev)
+{
+	struct bootdev_uc_plat *ucp = dev_get_uclass_plat(dev);
+
+	while (!list_empty(&ucp->bootflow_head)) {
+		struct bootflow *bflow;
+
+		bflow = list_first_entry(&ucp->bootflow_head, struct bootflow,
+					 bm_node);
+		/* later bootflow_remove(bflow); */
+	}
+}
+
+/**
+ * h_cmp_bootdev() - Compare two bootdevs to find out which should go first
+ *
+ * @v1: struct udevice * of first bootdev device
+ * @v2: struct udevice * of second bootdev device
+ * Return: sort order (<0 if dev1 < dev2, ==0 if equal, >0 if dev1 > dev2)
+ */
+static int h_cmp_bootdev(const void *v1, const void *v2)
+{
+	const struct udevice *dev1 = *(struct udevice **)v1;
+	const struct udevice *dev2 = *(struct udevice **)v2;
+	const struct bootdev_uc_plat *ucp1 = dev_get_uclass_plat(dev1);
+	const struct bootdev_uc_plat *ucp2 = dev_get_uclass_plat(dev2);
+	int diff;
+
+	/* Use priority first */
+	diff = ucp1->prio - ucp2->prio;
+	if (diff)
+		return diff;
+
+	/* Fall back to seq for devices of the same priority */
+	diff = dev_seq(dev1) - dev_seq(dev2);
+
+	return diff;
+}
+
+/**
+ * build_order() - Build the ordered list of bootdevs to use
+ *
+ * This builds an ordered list of devices by one of three methods:
+ * - using the boot_targets environment variable, if non-empty
+ * - using the bootdev-order devicetree property, if present
+ * - sorted by priority and sequence number
+ *
+ * @bootstd: BOOTSTD device to use
+ * @order: Bootdevs listed in default order
+ * @max_count: Number of entries in @order
+ * Return: number of bootdevs found in the ordering, or -E2BIG if the
+ * boot_targets string is too long, or -EXDEV if the ordering produced 0 results
+ */
+static int build_order(struct udevice *bootstd, struct udevice **order,
+		       int max_count)
+{
+	const char *overflow_target = NULL;
+	const char *const *labels;
+	struct udevice *dev;
+	const char *targets;
+	int i, ret, count;
+
+	targets = env_get("boot_targets");
+	labels = IS_ENABLED(CONFIG_BOOTSTD_FULL) ?
+		bootstd_get_bootdev_order(bootstd) : NULL;
+	if (targets) {
+		char str[BOOT_TARGETS_MAX_LEN];
+		char *target;
+
+		if (strlen(targets) >= BOOT_TARGETS_MAX_LEN)
+			return log_msg_ret("len", -E2BIG);
+
+		/* make a copy of the string, since strok() will change it */
+		strcpy(str, targets);
+		for (i = 0, target = strtok(str, " "); target;
+		     target = strtok(NULL, " ")) {
+			ret = bootdev_find_by_label(target, &dev);
+			if (!ret) {
+				if (i == max_count) {
+					overflow_target = target;
+					break;
+				}
+				order[i++] = dev;
+			}
+		}
+		count = i;
+	} else if (labels) {
+		int upto;
+
+		upto = 0;
+		for (i = 0; labels[i]; i++) {
+			ret = bootdev_find_by_label(labels[i], &dev);
+			if (!ret) {
+				if (upto == max_count) {
+					overflow_target = labels[i];
+					break;
+				}
+				order[upto++] = dev;
+			}
+		}
+		count = upto;
+	} else {
+		/* sort them into priority order */
+		count = max_count;
+		qsort(order, count, sizeof(struct udevice *), h_cmp_bootdev);
+	}
+
+	if (overflow_target) {
+		log_warning("Expected at most %d bootdevs, but overflowed with boot_target '%s'\n",
+			    max_count, overflow_target);
+	}
+
+	if (!count)
+		return log_msg_ret("targ", -EXDEV);
+
+	return count;
+}
+
+int bootdev_setup_iter_order(struct bootflow_iter *iter, struct udevice **devp)
+{
+	struct udevice *bootstd, *dev = *devp, **order;
+	int upto, i;
+	int count;
+	int ret;
+
+	ret = uclass_first_device_err(UCLASS_BOOTSTD, &bootstd);
+	if (ret) {
+		log_err("Missing bootstd device\n");
+		return log_msg_ret("std", ret);
+	}
+
+	/* Handle scanning a single device */
+	if (dev) {
+		iter->flags |= BOOTFLOWF_SINGLE_DEV;
+		return 0;
+	}
+
+	count = uclass_id_count(UCLASS_BOOTDEV);
+	if (!count)
+		return log_msg_ret("count", -ENOENT);
+
+	order = calloc(count, sizeof(struct udevice *));
+	if (!order)
+		return log_msg_ret("order", -ENOMEM);
+
+	/*
+	 * Get a list of bootdevs, in seq order (i.e. using aliases). There may
+	 * be gaps so try to count up high enough to find them all.
+	 */
+	for (i = 0, upto = 0; upto < count && i < 20 + count * 2; i++) {
+		ret = uclass_find_device_by_seq(UCLASS_BOOTDEV, i, &dev);
+		if (!ret)
+			order[upto++] = dev;
+	}
+	log_debug("Found %d bootdevs\n", count);
+	if (upto != count)
+		log_debug("Expected %d bootdevs, found %d using aliases\n",
+			  count, upto);
+
+	count = build_order(bootstd, order, upto);
+	if (count < 0) {
+		free(order);
+		return log_msg_ret("build", count);
+	}
+
+	iter->dev_order = order;
+	iter->num_devs = count;
+	iter->cur_dev = 0;
+
+	dev = *order;
+	ret = device_probe(dev);
+	if (ret)
+		return log_msg_ret("probe", ret);
+	*devp = dev;
+
+	return 0;
+}
+
+static int bootdev_post_bind(struct udevice *dev)
+{
+	struct bootdev_uc_plat *ucp = dev_get_uclass_plat(dev);
+
+	INIT_LIST_HEAD(&ucp->bootflow_head);
+
+	return 0;
+}
+
+static int bootdev_pre_unbind(struct udevice *dev)
+{
+	bootdev_clear_bootflows(dev);
+
+	return 0;
+}
+
+UCLASS_DRIVER(bootdev) = {
+	.id		= UCLASS_BOOTDEV,
+	.name		= "bootdev",
+	.flags		= DM_UC_FLAG_SEQ_ALIAS,
+	.per_device_plat_auto	= sizeof(struct bootdev_uc_plat),
+	.post_bind	= bootdev_post_bind,
+	.pre_unbind	= bootdev_pre_unbind,
+};