netdevsim: add support for flash_update overwrite mask

The devlink interface recently gained support for a new "overwrite mask"
parameter that allows specifying how various sub-sections of a flash
component are modified when updating.

Add support for this to netdevsim, to enable easily testing the
interface. Make the allowed overwrite mask values controllable via
a debugfs parameter. This enables testing a flow where the driver
rejects an unsupportable overwrite mask.

Signed-off-by: Jacob Keller <[e-mail]>
Reviewed-by: Jakub Kicinski <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/netdevsim/dev.c

···
 		return PTR_ERR(nsim_dev->ports_ddir);
 	debugfs_create_bool("fw_update_status", 0600, nsim_dev->ddir,
 			    &nsim_dev->fw_update_status);
+	debugfs_create_u32("fw_update_overwrite_mask", 0600, nsim_dev->ddir,
+			    &nsim_dev->fw_update_overwrite_mask);
 	debugfs_create_u32("max_macs", 0600, nsim_dev->ddir,
 			   &nsim_dev->max_macs);
 	debugfs_create_bool("test1", 0600, nsim_dev->ddir,
···
 	struct nsim_dev *nsim_dev = devlink_priv(devlink);
 	int i;
 
+	if ((params->overwrite_mask & ~nsim_dev->fw_update_overwrite_mask) != 0)
+		return -EOPNOTSUPP;
+
 	if (nsim_dev->fw_update_status) {
 		devlink_flash_update_begin_notify(devlink);
 		devlink_flash_update_status_notify(devlink,
···
 }
 
 static const struct devlink_ops nsim_dev_devlink_ops = {
-	.supported_flash_update_params = DEVLINK_SUPPORT_FLASH_UPDATE_COMPONENT,
+	.supported_flash_update_params = DEVLINK_SUPPORT_FLASH_UPDATE_COMPONENT |
+					 DEVLINK_SUPPORT_FLASH_UPDATE_OVERWRITE_MASK,
 	.reload_down = nsim_dev_reload_down,
 	.reload_up = nsim_dev_reload_up,
 	.info_get = nsim_dev_info_get,
···
 	INIT_LIST_HEAD(&nsim_dev->port_list);
 	mutex_init(&nsim_dev->port_list_lock);
 	nsim_dev->fw_update_status = true;
+	nsim_dev->fw_update_overwrite_mask = 0;
 
 	nsim_dev->fib_data = nsim_fib_create(devlink, extack);
 	if (IS_ERR(nsim_dev->fib_data))
···
 	INIT_LIST_HEAD(&nsim_dev->port_list);
 	mutex_init(&nsim_dev->port_list_lock);
 	nsim_dev->fw_update_status = true;
+	nsim_dev->fw_update_overwrite_mask = 0;
 	nsim_dev->max_macs = NSIM_DEV_MAX_MACS_DEFAULT;
 	nsim_dev->test1 = NSIM_DEV_TEST1_DEFAULT;
 	spin_lock_init(&nsim_dev->fa_cookie_lock);

drivers/net/netdevsim/netdevsim.h

···
 	struct list_head port_list;
 	struct mutex port_list_lock; /* protects port list */
 	bool fw_update_status;
+	u32 fw_update_overwrite_mask;
 	u32 max_macs;
 	bool test1;
 	bool dont_allow_reload;

tools/testing/selftests/drivers/net/netdevsim/devlink.sh

···
 	devlink dev flash $DL_HANDLE file dummy component fw.mgmt
 	check_err $? "Failed to flash with component attribute"
 
+	devlink dev flash $DL_HANDLE file dummy overwrite settings
+	check_fail $? "Flash with overwrite settings should be rejected"
+
+	echo "1"> $DEBUGFS_DIR/fw_update_overwrite_mask
+	check_err $? "Failed to change allowed overwrite mask"
+
+	devlink dev flash $DL_HANDLE file dummy overwrite settings
+	check_err $? "Failed to flash with settings overwrite enabled"
+
+	devlink dev flash $DL_HANDLE file dummy overwrite identifiers
+	check_fail $? "Flash with overwrite settings should be identifiers"
+
+	echo "3"> $DEBUGFS_DIR/fw_update_overwrite_mask
+	check_err $? "Failed to change allowed overwrite mask"
+
+	devlink dev flash $DL_HANDLE file dummy overwrite identifiers overwrite settings
+	check_err $? "Failed to flash with settings and identifiers overwrite enabled"
+
 	echo "n"> $DEBUGFS_DIR/fw_update_status
 	check_err $? "Failed to disable status updates"