[U-Boot] [PATCH v1] dfu: Avoid declaring unused variables and absent parameters

[Andy Shevchenko]

On Mon, Mar 04, 2019 at 04:04:44PM +0200, Andy Shevchenko wrote:
> The compiler is not happy when neither USB nor TFTP transport for DFU defined:
> 
> cmd/dfu.c: In function ‘do_dfu’:
> cmd/dfu.c:31:8: warning: unused variable ‘devstring’ [-Wunused-variable]
>   char *devstring = argv[3];
>         ^~~~~~~~~
> cmd/dfu.c:30:8: warning: unused variable ‘interface’ [-Wunused-variable]
>     char *interface = argv[2];
>           ^~~~~~~~~
> 
> Surround those variables by #ifdef expression.
> 
> More serious, that comes under same circumstances, is a compilation error due
> to absence of macro parameter:

Any comments on this?

I don't know who is the right person to push this forward, please, feel free to
Cc to the right one, or tell me to resend with proper Cc list.

> 
> In file included from include/image.h:45,
>                  from include/common.h:35,
>                  from cmd/dfu.c:13:
> include/command.h:207:24: error: expected expression before ‘,’ token
>  # define _CMD_HELP(x) x,
>                         ^
> include/command.h:286:18: note: in expansion of macro ‘_CMD_HELP’
>     _cmd, _usage, _CMD_HELP(_help) _CMD_COMPLETE(_comp) }
>                   ^~~~~~~~~
> include/command.h:290:3: note: in expansion of macro ‘U_BOOT_CMD_MKENT_COMPLETE’
>    U_BOOT_CMD_MKENT_COMPLETE(_name, _maxargs, _rep, _cmd, \
>    ^~~~~~~~~~~~~~~~~~~~~~~~~
> include/command.h:332:2: note: in expansion of macro ‘U_BOOT_CMD_COMPLETE’
>   U_BOOT_CMD_COMPLETE(_name, _maxargs, _rep, _cmd, _usage, _help, NULL)
>   ^~~~~~~~~~~~~~~~~~~
> cmd/dfu.c:70:1: note: in expansion of macro ‘U_BOOT_CMD’
>  U_BOOT_CMD(dfu, CONFIG_SYS_MAXARGS, 1, do_dfu,
>  ^~~~~~~~~~
> make[1]: *** [scripts/Makefile.build:279: cmd/dfu.o] Error 1
> make: *** [Makefile:1518: cmd] Error 2
> 
> Put empty string unconditionally to have macro parameter present.
> 
> Fixes: 0f44d33536a5 ("dfu: Fix up the Kconfig mess")
> Cc: Marek Vasut <marek.vasut at gmail.com>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
> ---
>  cmd/dfu.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/cmd/dfu.c b/cmd/dfu.c
> index 4adb91c1b0..498a30b33b 100644
> --- a/cmd/dfu.c
> +++ b/cmd/dfu.c
> @@ -27,8 +27,10 @@ static int do_dfu(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
>  #ifdef CONFIG_DFU_OVER_USB
>  	char *usb_controller = argv[1];
>  #endif
> +#if defined(CONFIG_DFU_OVER_USB) || defined(CONFIG_DFU_OVER_TFTP)
>  	char *interface = argv[2];
>  	char *devstring = argv[3];
> +#endif
>  
>  	int ret = 0;
>  #ifdef CONFIG_DFU_OVER_TFTP
> @@ -67,6 +69,7 @@ done:
>  
>  U_BOOT_CMD(dfu, CONFIG_SYS_MAXARGS, 1, do_dfu,
>  	"Device Firmware Upgrade",
> +	""
>  #ifdef CONFIG_DFU_OVER_USB
>  #ifdef CONFIG_DFU_TIMEOUT
>  	"<USB_controller> <interface> <dev> [list|timeout]\n"
> -- 
> 2.20.1
> 

-- 
With Best Regards,
Andy Shevchenko