[PATCH 3/3] commands: add new devunbind debugging command

[Sascha Hauer]

On Sat, Jan 08, 2022 at 06:14:26PM +0100, Ahmad Fatoum wrote:
> Memory corruption around device removal may go unnoticed, because
> barebox is shutting down anyway and doing no new allocations.
> 
> Add a new devunbind command that should help with debugging such issues
> by allowing selective unbinding and removal of devices.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> ---
>  commands/Kconfig      | 12 +++++++
>  commands/Makefile     |  1 +
>  commands/devunbind.c  | 74 +++++++++++++++++++++++++++++++++++++++++++
>  drivers/base/driver.c |  7 ++--
>  include/driver.h      |  4 +++
>  5 files changed, 95 insertions(+), 3 deletions(-)
>  create mode 100644 commands/devunbind.c
> 
> diff --git a/commands/Kconfig b/commands/Kconfig
> index e2c36949347e..9abd97271952 100644
> --- a/commands/Kconfig
> +++ b/commands/Kconfig
> @@ -68,6 +68,18 @@ config CMD_DEVINFO
>  	  If called with a device path being the argument, devinfo shows more
>  	  default information about this device and its parameters.
>  
> +config CMD_DEVUNBIND
> +	tristate
> +	default y
> +	prompt "devunbind"
> +	help
> +	  Debugging aid to unbind device from driver at runtime
> +
> +	  devunbind [-f] DEVICE
> +
> +	  Options:
> +	    -f   unbind driver and force removal of device and children
> +
>  config CMD_DMESG
>  	tristate
>  	prompt "dmesg"
> diff --git a/commands/Makefile b/commands/Makefile
> index 0b7c1563b534..875826743ffe 100644
> --- a/commands/Makefile
> +++ b/commands/Makefile
> @@ -107,6 +107,7 @@ obj-$(CONFIG_CMD_MIITOOL)	+= miitool.o
>  obj-$(CONFIG_CMD_DETECT)	+= detect.o
>  obj-$(CONFIG_CMD_BOOT)		+= boot.o
>  obj-$(CONFIG_CMD_DEVINFO)	+= devinfo.o
> +obj-$(CONFIG_CMD_DEVUNBIND)	+= devunbind.o
>  obj-$(CONFIG_CMD_DRVINFO)	+= drvinfo.o
>  obj-$(CONFIG_CMD_READF)		+= readf.o
>  obj-$(CONFIG_CMD_MENUTREE)	+= menutree.o
> diff --git a/commands/devunbind.c b/commands/devunbind.c
> new file mode 100644
> index 000000000000..4bebb27e8e68
> --- /dev/null
> +++ b/commands/devunbind.c
> @@ -0,0 +1,74 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +// SPDX-FileCopyrightText: © 2021 Ahmad Fatoum <a.fatoum at pengutronix.de>, Pengutronix
> +
> +#include <command.h>
> +#include <common.h>
> +#include <complete.h>
> +#include <driver.h>
> +#include <getopt.h>
> +
> +static int do_devunbind(int argc, char *argv[])
> +{
> +	bool unregister = false;
> +	struct device_d *dev;
> +	int ret = COMMAND_SUCCESS, i, opt;
> +
> +	while ((opt = getopt(argc, argv, "fl")) > 0) {
> +		switch (opt) {
> +		case 'f':
> +			unregister = true;
> +			break;
> +		case 'l':
> +			list_for_each_entry(dev, &active_device_list, active) {
> +				BUG_ON(!dev->driver);
> +				if (dev->bus->remove)
> +					printf("%pS(%s, %s)\n", dev->bus->remove,
> +					       dev->driver->name, dev_name(dev));
> +			}
> +			return 0;
> +		default:
> +			return COMMAND_ERROR_USAGE;
> +		}
> +	}
> +
> +	if (!argv[optind])
> +		return COMMAND_ERROR_USAGE;
> +
> +	for (i = optind; i < argc; i++) {
> +		dev = get_device_by_name(argv[i]);
> +		if (!dev)
> +			return -ENODEV;
> +
> +		if (unregister)
> +			return unregister_device(dev);

Shouldn't you continue the loop here?

Sascha

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