Merge patch series "Convert extension support to UCLASS and adds its support to boot flows"

Kory Maincent (TI.com) <[email protected]> says:

This series converts the extension board framework to use UCLASS as
requested by Simon Glass, then adds extension support to pxe_utils
and bootmeth_efi (not tested) to enable extension boards devicetree load
in the standard boot process.

I can't test the imx8 extension scan enabled by the
imx8mm-cl-iot-gate_defconfig as I don't have this board.
I also can't test the efi bootmeth change as I don't have such board.

Link: https://lore.kernel.org/r/20251030-feature_sysboot_extension_board-v5-0-cfb77672fc68@bootlin.com

2 files changed, 75 insertions, 12 deletions

diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 6be59093160..eb6416b5917 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -63,6 +63,7 @@ enum uclass_id {
 	UCLASS_ETH,		/* Ethernet device */
 	UCLASS_ETH_PHY,		/* Ethernet PHY device */
 	UCLASS_EXTCON,		/* External Connector Class */
+	UCLASS_EXTENSION,	/* Extension board */
 	UCLASS_FFA,		/* Arm Firmware Framework for Armv8-A */
 	UCLASS_FFA_EMUL,		/* sandbox FF-A device emulator */
 	UCLASS_FIRMWARE,	/* Firmware */
diff --git a/include/extension_board.h b/include/extension_board.h
index 22e4104bc54..0b9fb99ad7d 100644
--- a/include/extension_board.h
+++ b/include/extension_board.h
@@ -7,10 +7,58 @@
 #ifndef __EXTENSION_SUPPORT_H
 #define __EXTENSION_SUPPORT_H
 
+#include <alist.h>
+#include <dm/device.h>
 #include <linux/list.h>
+#include <dm/platdata.h>
 
+extern struct list_head extension_list;
+
+/**
+ * extension_get_list - Get the extension list
+ * Return: The extension alist pointer, or NULL if no such list exists.
+ *
+ * The caller must not free the list.
+ */
+struct alist *extension_get_list(void);
+
+/**
+ * extension_probe - Probe extension device
+ * @dev: Extension device that needs to be probed
+ * Return: Zero on success, negative on failure.
+ */
+int extension_probe(struct udevice *dev);
+
+/**
+ * extension_remove - Remove extension device
+ * @dev: Extension device that needs to be removed
+ * Return: Zero on success, negative on failure.
+ */
+int extension_remove(struct udevice *dev);
+
+/**
+ * extension_scan - Scan extension boards available.
+ * Return: Zero on success, negative on failure.
+ */
+int extension_scan(void);
+
+/**
+ * extension_apply - Apply extension board overlay to the devicetree
+ * @working_fdt: Pointer to working flattened device tree
+ * @size: Size of the devicetree overlay
+ * Return: Zero on success, negative on failure.
+ */
+int extension_apply(struct fdt_header *working_fdt, ulong size);
+
+/**
+ * extension - Description fields of an extension board
+ * @name: Name of the extension
+ * @owner: Owner of the extension
+ * @version: Version of the extension
+ * @overlay: Devicetree overlay name to be loaded for this extension
+ * @other: Other information of this extension
+ */
 struct extension {
-	struct list_head list;
 	char name[32];
 	char owner[32];
 	char version[32];
@@ -18,16 +66,30 @@ struct extension {
 	char other[32];
 };
 
-/**
- * extension_board_scan - Add system-specific function to scan extension board.
- * @param extension_list	List of extension board information to update.
- * Return: the number of extension.
- *
- * This function is called if CONFIG_CMD_EXTENSION is defined.
- * Needs to fill the list extension_list with elements.
- * Each element need to be allocated to an extension structure.
- *
- */
-int extension_board_scan(struct list_head *extension_list);
+struct extension_ops {
+	/**
+	 * scan - Add system-specific function to scan extension boards.
+	 * @dev: extension device
+	 * @extension_list: alist of extension to expand
+	 * Return: The number of extension or a negative value in case of
+	 *	   error.
+	 */
+	int (*scan)(struct udevice *dev, struct alist *extension_list);
+};
+
+#define extension_get_ops(dev)  ((struct extension_ops *)(dev)->driver->ops)
+
+/* Currently, only one extension driver enabled at a time is supported */
+#define U_BOOT_EXTENSION(_name, _scan_func) \
+	U_BOOT_DRIVER(_name) = { \
+		.name = #_name, \
+		.id = UCLASS_EXTENSION, \
+		.probe = extension_probe, \
+		.remove = extension_remove, \
+		.ops = &(struct extension_ops) { \
+		       .scan = _scan_func, \
+		       }, \
+		.priv_auto = sizeof(struct alist), \
+	}
 
 #endif /* __EXTENSION_SUPPORT_H */