[efi] Allow driver to be unloaded

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/efi/efi_driver.h

@@ -45,5 +45,6 @@ extern EFI_DEVICE_PATH_PROTOCOL *
 efi_devpath_end ( EFI_DEVICE_PATH_PROTOCOL *path );
 
 extern int efi_driver_install ( struct efi_driver *efidrv );
+extern void efi_driver_uninstall ( struct efi_driver *efidrv );
 
 #endif /* _IPXE_EFI_DRIVER_H */

src/interface/efi/efi_bofm.c

@@ -387,7 +387,7 @@ static struct efi_driver efi_bofm_driver =
  * Install EFI BOFM driver
  *
  */
-static void efi_bofm_driver_init ( void ) {
+static void efi_bofm_driver_startup ( void ) {
 	struct efi_driver *efidrv = &efi_bofm_driver;
 	int rc;
 
@@ -401,7 +401,19 @@ static void efi_bofm_driver_init ( void ) {
 	DBGC ( efidrv, "EFIBOFM driver installed\n" );
 }
 
+/**
+ * Shut down EFI BOFM driver
+ *
+ * @v booting		System is shutting down for OS boot
+ */
+static void efi_bofm_driver_shutdown ( int booting __unused ) {
+	struct efi_driver *efidrv = &efi_bofm_driver;
+
+	efi_driver_uninstall ( efidrv );
+}
+
 /** EFI BOFM startup function */
 struct startup_fn startup_bofm __startup_fn ( STARTUP_EARLY ) = {
-	.startup = efi_bofm_driver_init,
+	.startup = efi_bofm_driver_startup,
+	.shutdown = efi_bofm_driver_shutdown,
 };

src/interface/efi/efi_driver.c

@@ -122,7 +122,7 @@ efi_driver_get_controller_name ( EFI_COMPONENT_NAME2_PROTOCOL *wtf __unused,
  * Install EFI driver
  *
  * @v efidrv		EFI driver
- * @ret efirc		EFI status code
+ * @ret rc		Return status code
  */
 int efi_driver_install ( struct efi_driver *efidrv ) {
 	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
@@ -143,7 +143,9 @@ int efi_driver_install ( struct efi_driver *efidrv ) {
 	efi_snprintf ( efidrv->wname,
 		       ( sizeof ( efidrv->wname ) /
 			 sizeof ( efidrv->wname[0] ) ),
-		       PRODUCT_SHORT_NAME " - %s", efidrv->name );
+		       PRODUCT_SHORT_NAME "%s%s",
+		       ( efidrv->name ? " - " : "" ),
+		       ( efidrv->name ? efidrv->name : "" ) );
 
 	/* Install driver */
 	if ( ( efirc = bs->InstallMultipleProtocolInterfaces (
@@ -160,3 +162,43 @@ int efi_driver_install ( struct efi_driver *efidrv ) {
 	DBGC ( efidrv, "EFIDRV %s installed\n", efidrv->name );
 	return 0;
 }
+
+/**
+ * Uninstall EFI driver
+ *
+ * @v efidrv		EFI driver
+ */
+void efi_driver_uninstall ( struct efi_driver *efidrv ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+	EFI_HANDLE *handles;
+	UINTN num_handles;
+	EFI_STATUS efirc;
+	UINTN i;
+	int rc;
+
+	/* Disconnect the driver from its devices */
+	if ( ( efirc = bs->LocateHandleBuffer ( AllHandles, NULL, NULL,
+						&num_handles,
+						&handles ) ) != 0 ) {
+		rc = -EEFI ( efirc );
+		DBGC ( efidrv, "EFIDRV %s could not list handles: %s\n",
+		       efidrv->name, strerror ( rc ) );
+		/* No way to disconnect driver; leave it loaded */
+		return;
+	}
+	DBGC ( efidrv, "EFIDRV %s disconnecting devices\n", efidrv->name );
+	for ( i = 0 ; i < num_handles ; i++ ) {
+		bs->DisconnectController ( handles[i],
+					   efidrv->driver.DriverBindingHandle,
+					   NULL );
+	}
+	bs->FreePool ( handles );
+
+	/* Uninstall the driver */
+	bs->UninstallMultipleProtocolInterfaces (
+			efidrv->driver.DriverBindingHandle,
+			&efi_driver_binding_protocol_guid, &efidrv->driver,
+			&efi_component_name2_protocol_guid, &efidrv->wtf,
+			NULL );
+	DBGC ( efidrv, "EFIDRV %s uninstalled\n", efidrv->name );
+}

src/interface/efi/efi_init.c

@@ -22,6 +22,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <string.h>
 #include <errno.h>
 #include <ipxe/efi/efi.h>
+#include <ipxe/efi/efi_driver.h>
 #include <ipxe/efi/Protocol/LoadedImage.h>
 #include <ipxe/efi/Protocol/DevicePath.h>
 #include <ipxe/uuid.h>
@@ -50,6 +51,64 @@ static EFI_GUID efi_loaded_image_device_path_protocol_guid
 /** Event used to signal shutdown */
 static EFI_EVENT efi_shutdown_event;
 
+/* Forward declarations */
+static EFI_STATUS EFIAPI efi_unload ( EFI_HANDLE image_handle );
+
+/**
+ * Check to see if driver supports a device
+ *
+ * @v driver		EFI driver
+ * @v device		EFI device
+ * @v child		Path to child device, if any
+ * @ret efirc		EFI status code
+ */
+static EFI_STATUS EFIAPI
+efi_image_supported ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
+		    EFI_HANDLE device __unused,
+		    EFI_DEVICE_PATH_PROTOCOL *child __unused ) {
+
+	return EFI_UNSUPPORTED;
+}
+
+/**
+ * Attach driver to device
+ *
+ * @v driver		EFI driver
+ * @v device		EFI device
+ * @v child		Path to child device, if any
+ * @ret efirc		EFI status code
+ */
+static EFI_STATUS EFIAPI
+efi_image_start ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
+		EFI_HANDLE device __unused,
+		EFI_DEVICE_PATH_PROTOCOL *child __unused ) {
+
+	return EFI_UNSUPPORTED;
+}
+
+/**
+ * Detach driver from device
+ *
+ * @v driver		EFI driver
+ * @v device		EFI device
+ * @v pci		PCI device
+ * @v num_children	Number of child devices
+ * @v children		List of child devices
+ * @ret efirc		EFI status code
+ */
+static EFI_STATUS EFIAPI
+efi_image_stop ( EFI_DRIVER_BINDING_PROTOCOL *driver __unused,
+	       EFI_HANDLE device __unused, UINTN num_children __unused,
+	       EFI_HANDLE *children __unused ) {
+
+	return EFI_UNSUPPORTED;
+}
+
+/** EFI loaded image driver */
+static struct efi_driver efi_image_driver =
+	EFI_DRIVER_INIT ( NULL, efi_image_supported, efi_image_start,
+			  efi_image_stop );
+
 /**
  * Shut down in preparation for booting an OS.
  *
@@ -189,5 +248,43 @@ EFI_STATUS efi_init ( EFI_HANDLE image_handle,
 		return efirc;
 	}
 
+	/* Install an EFI driver on the image handle, to allow the
+	 * driver to be subsequently unloaded.
+	 */
+	efi_image_driver.driver.DriverBindingHandle = image_handle;
+	if ( ( rc = efi_driver_install ( &efi_image_driver ) ) != 0 ) {
+		DBGC ( systab, "EFI could not install loaded image driver: "
+		       "%s\n", strerror ( rc ) );
+		return EFIRC ( rc );
+	}
+
+	/* Install image unload method */
+	efi_loaded_image->Unload = efi_unload;
+
+	return 0;
+}
+
+/**
+ * Shut down EFI environment
+ *
+ * @v image_handle	Image handle
+ */
+static EFI_STATUS EFIAPI efi_unload ( EFI_HANDLE image_handle __unused ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+	EFI_SYSTEM_TABLE *systab = efi_systab;
+
+	DBGC ( systab, "EFI image unloading\n" );
+
+	/* Shut down */
+	shutdown_exit();
+
+	/* Uninstall exit boot services event */
+	bs->CloseEvent ( efi_shutdown_event );
+
+	/* Uninstall loaded image driver */
+	efi_driver_uninstall ( &efi_image_driver );
+
+	DBGC ( systab, "EFI image unloaded\n" );
+
 	return 0;
 }

src/interface/efi/efi_pci.c

@@ -519,6 +519,9 @@ static void efipci_driver_shutdown ( int booting __unused ) {
 	struct efi_pci_device *efipci;
 	struct efi_pci_device *tmp;
 
+	/* Uninstall driver */
+	efi_driver_uninstall ( efidrv );
+
 	/* Shut down any remaining devices */
 	list_for_each_entry_safe ( efipci, tmp, &efi_pci_devices, list ) {
 		DBGC ( efipci, "EFIPCI " PCI_FMT " still active at shutdown; "