Merge branch '2023-01-24-bootstd-allow-migration-from-distro_bootcmd-script'

To quote the author:
So far, standard boot does not replicate all the of the functionality
of the distro_bootcmd scripts. In particular it lacks some bootdevs and
some of the bootmeths are incomplete.

Also there is currently no internal mechanism to enumerate buses in order
to discover bootdevs, e.g. with USB.

This series addresses these shortcomings:

- Adds the concept of a 'bootdev hunter' to enumerate buses, etc. in an
  effort to find bootdevs of a certain priority
- Adds bootdevs for SCSI, IDE, NVMe, virtio, SPI flash
- Handles PXE and DHCP properly
- Supports reading the device tree with EFI and reading scripts from the
  network

It also tidies up label processing, so it is possible to use:

   bootflow scan mmc2

to scan just one MMC device (with BOOTSTD_FULL).

As before this implementation still relies on CONFIG_CMDLINE being
enabled, mostly for the network stack. Further work would be required to
disentangle that.

Quite a few tests are added but there are some gaps:

- SPI flash bootdev
- EFI FDT loading

Note that SATA works via SCSI (CONFIG_SCSI_AHCI) and does not use
driver model. Only pogo_v4 seems to be affected. Probably all thats is
needed is to call bootdev_setup_sibling_blk() in the Marvell SATA driver.

Also, while it would be possible to init MMC in a bootdev hunter, there is
no point since U-Boot always inits MMC on startup, if present.

With this series it should be possible to migrate boards to standard boot
by removing the inclusion of config_distro_bootcmd.h and instead adding
a suitable value for boot_targets to the environment, e.g.:

   boot_targets=mmc1 mmc0 nvme scsi usb pxe dhcp spi

Thus it is possible to boot automatically without scripts and boards can
use a text-based environment instead of the config.h files.

To demonstrate this, rockpro64-rk3399 is migrated to standard boot in this
series. Full migration could probably be automated using a script, similar
in concept to moveconfig:

   - obtain the board environment via 'make u-boot-initial-env'
   - get the value of "boot_targets"
   - drop config_distro_bootcmd.h from the config.h file
   - rebuild again to get the environment without distro scripts
   - write the environment (adding boot_targets) to board.env
   - remove CONFIG_EXTRA_ENV_SETTINGS from the config.h file

1 files changed, 187 insertions, 19 deletions

diff --git a/include/bootdev.h b/include/bootdev.h
index 9fc219839fe..b92ff4d4f15 100644
--- a/include/bootdev.h
+++ b/include/bootdev.h
@@ -11,6 +11,7 @@
 
 struct bootflow;
 struct bootflow_iter;
+struct bootstd_priv;
 struct udevice;
 
 /**
@@ -20,19 +21,87 @@ struct udevice;
  *
  * Smallest value is the highest priority. By default, bootdevs are scanned from
  * highest to lowest priority
+ *
+ * BOOTDEVP_0_NONE: Invalid value, do not use
+ * @BOOTDEVP_6_PRE_SCAN: Scan bootdevs with this priority always, before
+ * starting any bootflow scan
+ * @BOOTDEVP_2_INTERNAL_FAST: Internal devices which don't need scanning and
+ * generally very quick to access, e.g. less than 100ms
+ * @BOOTDEVP_3_INTERNAL_SLOW: Internal devices which don't need scanning but
+ * take a significant fraction of a second to access
+ * @BOOTDEVP_4_SCAN_FAST: Extenal devices which need scanning or bus
+ * enumeration to find, but this enumeration happens quickly, typically under
+ * 100ms
+ * @BOOTDEVP_5_SCAN_SLOW: Extenal devices which need scanning or bus
+ * enumeration to find. The enumeration takes significant fraction of a second
+ * to complete
+ * @BOOTDEVP_6_NET_BASE: Basic network devices which are quickly and easily
+ * available. Typically used for an internal Ethernet device
+ * @BOOTDEVP_7_NET_FALLBACK: Secondary network devices which require extra time
+ * to start up, or are less desirable. Typically used for secondary Ethernet
+ * devices. Note that USB ethernet devices are found during USB enumeration,
+ * so do not use this priority
  */
 enum bootdev_prio_t {
-	BOOTDEVP_0_INTERNAL_FAST	= 10,
-	BOOTDEVP_1_INTERNAL_SLOW	= 20,
-	BOOTDEVP_2_SCAN_FAST		= 30,
-	BOOTDEVP_3_SCAN_SLOW		= 40,
-	BOOTDEVP_4_NET_BASE		= 50,
-	BOOTDEVP_5_NET_FALLBACK		= 60,
-	BOOTDEVP_6_SYSTEM		= 70,
+	BOOTDEVP_0_NONE,
+	BOOTDEVP_1_PRE_SCAN,
+	BOOTDEVP_2_INTERNAL_FAST,
+	BOOTDEVP_3_INTERNAL_SLOW,
+	BOOTDEVP_4_SCAN_FAST,
+	BOOTDEVP_5_SCAN_SLOW,
+	BOOTDEVP_6_NET_BASE,
+	BOOTDEVP_7_NET_FALLBACK,
 
 	BOOTDEVP_COUNT,
 };
 
+struct bootdev_hunter;
+
+/**
+ * bootdev_hunter_func - function to probe for bootdevs of a given type
+ *
+ * This should hunt around for bootdevs of the given type, binding them as it
+ * finds them. This may involve bus enumeration, etc.
+ *
+ * @info: Info structure describing this hunter
+ * @show: true to show information from the hunter
+ * Returns: 0 if OK, -ve on error
+ */
+typedef int (*bootdev_hunter_func)(struct bootdev_hunter *info, bool show);
+
+/**
+ * struct bootdev_hunter - information about how to hunt for bootdevs
+ *
+ * @prio: Scanning priority of this hunter
+ * @uclass: Uclass ID for the media associated with this bootdev
+ * @drv: bootdev driver for the things found by this hunter
+ * @hunt: Function to call to hunt for bootdevs of this type (NULL if none)
+ *
+ * Some bootdevs are not visible until other devices are enumerated. For
+ * example, USB bootdevs only appear when the USB bus is enumerated.
+ *
+ * On the other hand, we don't always want to enumerate all the buses just to
+ * find the first valid bootdev. Ideally we want to work through them in
+ * priority order, so that the fastest bootdevs are discovered first.
+ *
+ * This struct holds information about the bootdev so we can determine the probe
+ * order and how to hunt for bootdevs of this type
+ */
+struct bootdev_hunter {
+	enum bootdev_prio_t prio;
+	enum uclass_id uclass;
+	struct driver *drv;
+	bootdev_hunter_func hunt;
+};
+
+/* declare a new bootdev hunter */
+#define BOOTDEV_HUNTER(__name)						\
+	ll_entry_declare(struct bootdev_hunter, __name, bootdev_hunter)
+
+/* access a bootdev hunter by name */
+#define BOOTDEV_HUNTER_GET(__name)						\
+	ll_entry_get(struct bootdev_hunter, __name, bootdev_hunter)
+
 /**
  * struct bootdev_uc_plat - uclass information about a bootdev
  *
@@ -50,7 +119,10 @@ struct bootdev_uc_plat {
 /** struct bootdev_ops - Operations for the bootdev uclass */
 struct bootdev_ops {
 	/**
-	 * get_bootflow() - get a bootflow
+	 * get_bootflow() - get a bootflow (optional)
+	 *
+	 * If this is NULL then the default implementaton is used, which is
+	 * default_get_bootflow()
 	 *
 	 * @dev:	Bootflow device to check
 	 * @iter:	Provides current dev, part, method to get. Should update
@@ -171,40 +243,136 @@ int bootdev_next_bootflow(struct bootflow **bflowp);
  * @label: Label to look up (e.g. "mmc1" or "mmc0")
  * @devp: Returns the bootdev device found, or NULL if none (note it does not
  *	return the media device, but its bootdev child)
+ * @method_flagsp: If non-NULL, returns any flags implied by the label
+ * (enum bootflow_meth_flags_t), 0 if none. Unset if function fails
  * Return: 0 if OK, -EINVAL if the uclass is not supported by this board,
- *	-ENOENT if there is no device with that number
+ * -ENOENT if there is no device with that number
  */
-int bootdev_find_by_label(const char *label, struct udevice **devp);
+int bootdev_find_by_label(const char *label, struct udevice **devp,
+			  int *method_flagsp);
 
 /**
  * bootdev_find_by_any() - Find a bootdev by name, label or sequence
  *
  * @name: name (e.g. "mmc2.bootdev"), label ("mmc2"), or sequence ("2") to find
  * @devp: returns the device found, on success
- * Return: 0 if OK, -ve on error
+ * @method_flagsp: If non-NULL, returns any flags implied by the label
+ * (enum bootflow_meth_flags_t), 0 if none. Unset if function fails
+ * Return: 0 if OK, -EINVAL if the uclass is not supported by this board,
+ * -ENOENT if there is no device with that number
  */
-int bootdev_find_by_any(const char *name, struct udevice **devp);
+int bootdev_find_by_any(const char *name, struct udevice **devp,
+			int *method_flagsp);
 
 /**
- * bootdev_setup_iter_order() - Set up the ordering of bootdevs to scan
- *
- * This sets up the ordering information in @iter, based on the priority of each
- * bootdev and the bootdev-order property in the bootstd node
+ * bootdev_setup_iter() - Set up iteration through bootdevs
  *
- * If a single device is requested, no ordering is needed
+ * This sets up the an interation, based on the provided device or label. If
+ * neither is provided, the iteration is based on the priority of each bootdev,
+ * the * bootdev-order property in the bootstd node (or the boot_targets env
+ * var).
  *
  * @iter: Iterator to update with the order
+ * @label: label to scan, or NULL to scan all
  * @devp: On entry, *devp is NULL to scan all, otherwise this is the (single)
  *	device to scan. Returns the first device to use, which is the passed-in
  *	@devp if it was non-NULL
+ * @method_flagsp: If non-NULL, returns any flags implied by the label
+ * (enum bootflow_meth_flags_t), 0 if none
  * Return: 0 if OK, -ENOENT if no bootdevs, -ENOMEM if out of memory, other -ve
  *	on other error
  */
-int bootdev_setup_iter_order(struct bootflow_iter *iter, struct udevice **devp);
+int bootdev_setup_iter(struct bootflow_iter *iter, const char *label,
+		       struct udevice **devp, int *method_flagsp);
+
+/**
+ * bootdev_list_hunters() - List the available bootdev hunters
+ *
+ * These provide a way to find new bootdevs by enumerating buses, etc. This
+ * function lists the available hunters
+ *
+ * @std: Pointer to bootstd private info
+ */
+void bootdev_list_hunters(struct bootstd_priv *std);
+
+/**
+ * bootdev_hunt() - Hunt for bootdevs matching a particular spec
+ *
+ * This runs the selected hunter (or all if @spec is NULL) to try to find new
+ * bootdevs.
+ *
+ * @spec: Spec to match, e.g. "mmc0", or NULL for any. If provided, this must
+ * match a uclass name so that the hunter can be determined. Any trailing number
+ * is ignored
+ * @show: true to show each hunter before using it
+ * Returns: 0 if OK, -ve on error
+ */
+int bootdev_hunt(const char *spec, bool show);
+
+/**
+ * bootdev_hunt_prio() - Hunt for bootdevs of a particular priority
+ *
+ * This runs all hunters which can find bootdevs of the given priority.
+ *
+ * @prio: Priority to use
+ * @show: true to show each hunter as it is used
+ * Returns: 0 if OK, -ve on error
+ */
+int bootdev_hunt_prio(enum bootdev_prio_t prio, bool show);
+
+/**
+ * bootdev_hunt_and_find_by_label() - Hunt for bootdevs by label
+ *
+ * Runs the hunter for the label, then tries to find the bootdev, possible
+ * created by the hunter
+ *
+ * @label: Label to look up (e.g. "mmc1" or "mmc0")
+ * @devp: Returns the bootdev device found, or NULL if none (note it does not
+ *	return the media device, but its bootdev child)
+ * @method_flagsp: If non-NULL, returns any flags implied by the label
+ * (enum bootflow_meth_flags_t), 0 if none. Unset if function fails
+ * Return: 0 if OK, -EINVAL if the uclass is not supported by this board,
+ * -ENOENT if there is no device with that number
+ */
+int bootdev_hunt_and_find_by_label(const char *label, struct udevice **devp,
+				   int *method_flagsp);
+
+/**
+ * bootdev_next_label() - Move to the next bootdev in the label sequence
+ *
+ * Looks through the remaining labels until it finds one that matches a bootdev.
+ * Bootdev scanners are used as needed. For example a label "mmc1" results in
+ * running the "mmc" bootdrv.
+ *
+ * @iter: Interation info, containing iter->cur_label
+ * @devp: New bootdev found, if any was found
+ * @method_flagsp: If non-NULL, returns any flags implied by the label
+ * (enum bootflow_meth_flags_t), 0 if none
+ * Returns 0 if OK, -ENODEV if no bootdev was found
+ */
+int bootdev_next_label(struct bootflow_iter *iter, struct udevice **devp,
+		       int *method_flagsp);
+
+/**
+ * bootdev_next_prio() - Find the next bootdev in priority order
+ *
+ * This moves @devp to the next bootdev with the current priority. If there is
+ * none, then it moves to the next priority and scans for new bootdevs there.
+ *
+ * @iter: Interation info, containing iter->cur_prio
+ * @devp: On entry this is the previous bootdev that was considered. On exit
+ *	this is the new bootdev, if any was found
+ * Returns 0 on success (*devp is updated), -ENODEV if there are no more
+ * bootdevs at any priority
+ */
+int bootdev_next_prio(struct bootflow_iter *iter, struct udevice **devp);
 
 #if CONFIG_IS_ENABLED(BOOTSTD)
 /**
- * bootdev_setup_for_dev() - Bind a new bootdev device
+ * bootdev_setup_for_dev() - Bind a new bootdev device (deprecated)
+ *
+ * Please use bootdev_setup_sibling_blk() instead since it supports multiple
+ * (child) block devices for each media device.
  *
  * Creates a bootdev device as a child of @parent. This should be called from
  * the driver's bind() method or its uclass' post_bind() method.