Re: [PATCH v2 01/19] ARM: i.MX: boot: Coalesce copy-pasted code

[Andrey Smirnov <andrew.smirnov@gmail.com>]

On Wed, Apr 18, 2018 at 1:15 AM, Sascha Hauer <s.hauer@pengutronix.de> wrote:
> On Tue, Apr 17, 2018 at 08:20:46AM -0700, Andrey Smirnov wrote:
>> On Mon, Apr 16, 2018 at 11:58 PM, Sascha Hauer <s.hauer@pengutronix.de> wrote:
>> > On Mon, Apr 16, 2018 at 12:31:39PM -0700, Andrey Smirnov wrote:
>> >> All of the instances of imx*_boot_save_loc() do exactly the same thing with
>> >> the only difference being SoC-specific imx*_get_boot_source
>> >> call. Convert the code into a generic function taking function pointer
>> >> + a macro to take care of the boilerplate.
>> >>
>> >> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
>> >> ---
>> >>  arch/arm/mach-imx/boot.c | 85 ++++++++++--------------------------------------
>> >>  1 file changed, 17 insertions(+), 68 deletions(-)
>> >>
>> >> +imx_boot_save_loc(void (*get_boot_source)(enum bootsource *, int *))
>> >>  {
>> >>       enum bootsource src = BOOTSOURCE_UNKNOWN;
>> >>       int instance = BOOTSOURCE_INSTANCE_UNKNOWN;
>> >>
>> >> -     imx7_get_boot_source(&src, &instance);
>> >> +     get_boot_source(&src, &instance);
>> >>
>> >>       bootsource_set(src);
>> >>       bootsource_set_instance(instance);
>> >>  }
>> >> +
>> >> +#define IMX_BOOT_SAVE_LOC(soc)                                       \
>> >> +     void soc##_boot_save_loc(void)                          \
>> >> +     {                                                       \
>> >> +             imx_boot_save_loc(soc##_get_boot_source);       \
>> >> +     }
>> >> +
>> >> +IMX_BOOT_SAVE_LOC(imx25)
>> >> +IMX_BOOT_SAVE_LOC(imx27)
>> >> +IMX_BOOT_SAVE_LOC(imx35)
>> >> +IMX_BOOT_SAVE_LOC(imx51)
>> >> +IMX_BOOT_SAVE_LOC(imx53)
>> >> +IMX_BOOT_SAVE_LOC(imx6)
>> >> +IMX_BOOT_SAVE_LOC(imx7)
>> >
>> > I do not really like this patch. Yes, it saves a few lines of code, but
>> > with the cost of making it less readable.
>> >
>>
>> Can you elaborate on what part is less readable? IMHO, replacing 68
>> line of mostly copy pasted code with 17 of a generic function is a bit
>> more than "saving a few lines of code", so I think it's worth trying
>> to find a solution that would be acceptable from both perspectives:
>> conciseness and readability.
>
> I think it's bad when grepping for a function name only reveals the
> callers, maybe the declaraion, but not the definition of a function.
> Using macros to define functions is sometimes very effective (and done
> in barebox at other places), but not very nice to look at.
>
>>
>> Would replacing function pointer with a switch (imx_cpu_type) and
>> expanding IMX_BOOT_SAVE_LOC() make this patch readable enough to be
>> accepted?
>
> Not sure what exactly you mean, but the following should be fine. With
> a bit of violating the coding style this is not longer than your solution,
> but without hiding the function names behind a macro:
>
> void vf610_boot_save_loc(void) { boot_save_loc(vf610_get_boot_source); }
>

That's what I meant by "expanding IMX_BOOT_SAVE_LOC()". I'll update
the patch and re-submit it.

Thanks,
Andrey Smirnov

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