Merge branch '2022-04-25-initial-implementation-of-stdboot'

To quote the author:
The bootflow feature provide a built-in way for U-Boot to automatically
boot an Operating System without custom scripting and other customisation.
This is called 'standard boot' since it provides a standard way for
U-Boot to boot a distro, without scripting.

It introduces the following concepts:

   - bootdev - a device which can hold a distro
   - bootmeth - a method to scan a bootdev to find bootflows (owned by
                U-Boot)
   - bootflow - a description of how to boot (owned by the distro)

This series provides an implementation of these, enabled to scan for
bootflows from MMC, USB and Ethernet. It supports the existing distro
boot as well as the EFI loader flow (bootefi/bootmgr). It works
similiarly to the existing script-based approach, but is native to
U-Boot.

With this we can boot on a Raspberry Pi 3 with just one command:

   bootflow scan -lb

which means to scan, listing (-l) each bootflow and trying to boot each
one (-b). The final patch shows this.

With a standard way to identify boot devices, booting become easier. It
also should be possible to support U-Boot scripts, for backwards
compatibility only.

...

The design is described in these two documents:

https://drive.google.com/file/d/1ggW0KJpUOR__vBkj3l61L2dav4ZkNC12/view?usp=sharing

https://drive.google.com/file/d/1kTrflO9vvGlKp-ZH_jlgb9TY3WYG6FF9/view?usp=sharing

7 files changed, 176 insertions, 6 deletions

diff --git a/drivers/block/blk-uclass.c b/drivers/block/blk-uclass.c
index 791e26c06eb..21c5209bb63 100644
--- a/drivers/block/blk-uclass.c
+++ b/drivers/block/blk-uclass.c
@@ -509,6 +509,13 @@ int blk_get_from_parent(struct udevice *parent, struct udevice **devp)
 	return 0;
 }
 
+const char *blk_get_devtype(struct udevice *dev)
+{
+	struct udevice *parent = dev_get_parent(dev);
+
+	return uclass_get_name(device_get_uclass_id(parent));
+};
+
 int blk_find_max_devnum(enum if_type if_type)
 {
 	struct udevice *dev;
diff --git a/drivers/core/uclass.c b/drivers/core/uclass.c
index 2578803b7a4..08d9ed82de2 100644
--- a/drivers/core/uclass.c
+++ b/drivers/core/uclass.c
@@ -180,14 +180,15 @@ void uclass_set_priv(struct uclass *uc, void *priv)
 	uc->priv_ = priv;
 }
 
-enum uclass_id uclass_get_by_name_len(const char *name, int len)
+enum uclass_id uclass_get_by_namelen(const char *name, int len)
 {
 	int i;
 
 	for (i = 0; i < UCLASS_COUNT; i++) {
 		struct uclass_driver *uc_drv = lists_uclass_lookup(i);
 
-		if (uc_drv && !strncmp(uc_drv->name, name, len))
+		if (uc_drv && !strncmp(uc_drv->name, name, len) &&
+		    strlen(uc_drv->name) == len)
 			return i;
 	}
 
@@ -196,7 +197,7 @@ enum uclass_id uclass_get_by_name_len(const char *name, int len)
 
 enum uclass_id uclass_get_by_name(const char *name)
 {
-	return uclass_get_by_name_len(name, strlen(name));
+	return uclass_get_by_namelen(name, strlen(name));
 }
 
 int dev_get_uclass_index(struct udevice *dev, struct uclass **ucp)
@@ -273,8 +274,8 @@ int uclass_find_next_device(struct udevice **devp)
 	return 0;
 }
 
-int uclass_find_device_by_name(enum uclass_id id, const char *name,
-			       struct udevice **devp)
+int uclass_find_device_by_namelen(enum uclass_id id, const char *name, int len,
+				  struct udevice **devp)
 {
 	struct uclass *uc;
 	struct udevice *dev;
@@ -288,7 +289,8 @@ int uclass_find_device_by_name(enum uclass_id id, const char *name,
 		return ret;
 
 	uclass_foreach_dev(dev, uc) {
-		if (!strcmp(dev->name, name)) {
+		if (!strncmp(dev->name, name, len) &&
+		    strlen(dev->name) == len) {
 			*devp = dev;
 			return 0;
 		}
@@ -297,6 +299,12 @@ int uclass_find_device_by_name(enum uclass_id id, const char *name,
 	return -ENODEV;
 }
 
+int uclass_find_device_by_name(enum uclass_id id, const char *name,
+			       struct udevice **devp)
+{
+	return uclass_find_device_by_namelen(id, name, strlen(name), devp);
+}
+
 int uclass_find_next_free_seq(struct uclass *uc)
 {
 	struct udevice *dev;
diff --git a/drivers/mmc/Makefile b/drivers/mmc/Makefile
index 17ebc04203e..96275093022 100644
--- a/drivers/mmc/Makefile
+++ b/drivers/mmc/Makefile
@@ -5,6 +5,11 @@
 
 obj-y += mmc.o
 obj-$(CONFIG_$(SPL_)DM_MMC) += mmc-uclass.o
+
+ifdef CONFIG_$(SPL_TPL_)DM_MMC
+obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += mmc_bootdev.o
+endif
+
 obj-$(CONFIG_$(SPL_)MMC_WRITE) += mmc_write.o
 obj-$(CONFIG_MMC_PWRSEQ) += mmc-pwrseq.o
 obj-$(CONFIG_MMC_SDHCI_ADMA_HELPERS) += sdhci-adma.o
diff --git a/drivers/mmc/mmc-uclass.c b/drivers/mmc/mmc-uclass.c
index 57da788ad80..688bdc06d42 100644
--- a/drivers/mmc/mmc-uclass.c
+++ b/drivers/mmc/mmc-uclass.c
@@ -8,6 +8,7 @@
 #define LOG_CATEGORY UCLASS_MMC
 
 #include <common.h>
+#include <bootdev.h>
 #include <log.h>
 #include <mmc.h>
 #include <dm.h>
@@ -315,6 +316,20 @@ int mmc_get_next_devnum(void)
 	return blk_find_max_devnum(IF_TYPE_MMC);
 }
 
+int mmc_get_blk(struct udevice *dev, struct udevice **blkp)
+{
+	struct udevice *blk;
+	int ret;
+
+	device_find_first_child_by_uclass(dev, UCLASS_BLK, &blk);
+	ret = device_probe(blk);
+	if (ret)
+		return ret;
+	*blkp = blk;
+
+	return 0;
+}
+
 struct blk_desc *mmc_get_blk_desc(struct mmc *mmc)
 {
 	struct blk_desc *desc;
@@ -406,6 +421,10 @@ int mmc_bind(struct udevice *dev, struct mmc *mmc, const struct mmc_config *cfg)
 	mmc->cfg = cfg;
 	mmc->priv = dev;
 
+	ret = bootdev_setup_for_dev(dev, "mmc_bootdev");
+	if (ret)
+		return log_msg_ret("bootdev", ret);
+
 	/* the following chunk was from mmc_register() */
 
 	/* Setup dsr related values */
@@ -424,12 +443,16 @@ int mmc_bind(struct udevice *dev, struct mmc *mmc, const struct mmc_config *cfg)
 int mmc_unbind(struct udevice *dev)
 {
 	struct udevice *bdev;
+	int ret;
 
 	device_find_first_child_by_uclass(dev, UCLASS_BLK, &bdev);
 	if (bdev) {
 		device_remove(bdev, DM_REMOVE_NORMAL);
 		device_unbind(bdev);
 	}
+	ret = bootdev_unbind_dev(dev);
+	if (ret)
+		return log_msg_ret("bootdev", ret);
 
 	return 0;
 }
diff --git a/drivers/mmc/mmc_bootdev.c b/drivers/mmc/mmc_bootdev.c
new file mode 100644
index 00000000000..b4f41fb3a67
--- /dev/null
+++ b/drivers/mmc/mmc_bootdev.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Bootdevice for MMC
+ *
+ * Copyright 2021 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <bootdev.h>
+#include <dm.h>
+#include <mmc.h>
+
+static int mmc_get_bootflow(struct udevice *dev, struct bootflow_iter *iter,
+			    struct bootflow *bflow)
+{
+	struct udevice *mmc_dev = dev_get_parent(dev);
+	struct udevice *blk;
+	int ret;
+
+	ret = mmc_get_blk(mmc_dev, &blk);
+	/*
+	 * If there is no media, indicate that no more partitions should be
+	 * checked
+	 */
+	if (ret == -EOPNOTSUPP)
+		ret = -ESHUTDOWN;
+	if (ret)
+		return log_msg_ret("blk", ret);
+	assert(blk);
+	ret = bootdev_find_in_blk(dev, blk, iter, bflow);
+	if (ret)
+		return log_msg_ret("find", ret);
+
+	return 0;
+}
+
+static int mmc_bootdev_bind(struct udevice *dev)
+{
+	struct bootdev_uc_plat *ucp = dev_get_uclass_plat(dev);
+
+	ucp->prio = BOOTDEVP_0_INTERNAL_FAST;
+
+	return 0;
+}
+
+struct bootdev_ops mmc_bootdev_ops = {
+	.get_bootflow	= mmc_get_bootflow,
+};
+
+static const struct udevice_id mmc_bootdev_ids[] = {
+	{ .compatible = "u-boot,bootdev-mmc" },
+	{ }
+};
+
+U_BOOT_DRIVER(mmc_bootdev) = {
+	.name		= "mmc_bootdev",
+	.id		= UCLASS_BOOTDEV,
+	.ops		= &mmc_bootdev_ops,
+	.bind		= mmc_bootdev_bind,
+	.of_match	= mmc_bootdev_ids,
+};
diff --git a/drivers/usb/host/Makefile b/drivers/usb/host/Makefile
index a4472da9f18..7785b3744ef 100644
--- a/drivers/usb/host/Makefile
+++ b/drivers/usb/host/Makefile
@@ -8,6 +8,10 @@ obj-y += usb-uclass.o
 obj-$(CONFIG_SANDBOX) += usb-sandbox.o
 endif
 
+ifdef CONFIG_$(SPL_TPL_)USB_STORAGE
+obj-$(CONFIG_$(SPL_TPL_)BOOTSTD) += usb_bootdev.o
+endif
+
 # ohci
 obj-$(CONFIG_USB_OHCI_NEW) += ohci-hcd.o
 obj-$(CONFIG_USB_ATMEL) += ohci-at91.o
diff --git a/drivers/usb/host/usb_bootdev.c b/drivers/usb/host/usb_bootdev.c
new file mode 100644
index 00000000000..b85f699933d
--- /dev/null
+++ b/drivers/usb/host/usb_bootdev.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Bootdevice for USB
+ *
+ * Copyright 2021 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#include <common.h>
+#include <bootdev.h>
+#include <dm.h>
+#include <usb.h>
+
+static int usb_get_bootflow(struct udevice *dev, struct bootflow_iter *iter,
+			    struct bootflow *bflow)
+{
+	struct udevice *blk;
+	int ret;
+
+	ret = bootdev_get_sibling_blk(dev, &blk);
+	/*
+	 * If there is no media, indicate that no more partitions should be
+	 * checked
+	 */
+	if (ret == -EOPNOTSUPP)
+		ret = -ESHUTDOWN;
+	if (ret)
+		return log_msg_ret("blk", ret);
+	assert(blk);
+	ret = bootdev_find_in_blk(dev, blk, iter, bflow);
+	if (ret)
+		return log_msg_ret("find", ret);
+
+	return 0;
+}
+
+static int usb_bootdev_bind(struct udevice *dev)
+{
+	struct bootdev_uc_plat *ucp = dev_get_uclass_plat(dev);
+
+	ucp->prio = BOOTDEVP_3_SCAN_SLOW;
+
+	return 0;
+}
+
+struct bootdev_ops usb_bootdev_ops = {
+	.get_bootflow	= usb_get_bootflow,
+};
+
+static const struct udevice_id usb_bootdev_ids[] = {
+	{ .compatible = "u-boot,bootdev-usb" },
+	{ }
+};
+
+U_BOOT_DRIVER(usb_bootdev) = {
+	.name		= "usb_bootdev",
+	.id		= UCLASS_BOOTDEV,
+	.ops		= &usb_bootdev_ops,
+	.bind		= usb_bootdev_bind,
+	.of_match	= usb_bootdev_ids,
+};