[PATCH 1/1] video: avoid build failure on veyron board

[Alvaro Fernando García]

Hello Simon,

El vie, 4 ago 2023 a la(s) 00:02, Simon Glass (sjg at google.com) escribió:

> Hi,
>
> On Thu, 3 Aug 2023 at 18:37, Alvaro Fernando García
> <alvarofernandogarcia at gmail.com> wrote:
> >
> > 533ad9dc avoided an overflow but causes compilation
> > failure on 32bit boards (eg. veyron speedy)
> >
> > this commit uses div_u64 which has a fallback codepath
> > for 32bit platforms
> >
> > Signed-off-by: Alvaro Fernando García <alvarofernandogarcia at gmail.com>
> > ---
> >
> >  drivers/video/pwm_backlight.c | 7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
>
> Tested-by: Simon Glass <sjg at chromium.org>  # chromebook_jerry
>
> Can you please advise which toolchain you are using and what the
> warning actually says? I don't see this on my board.
>
> >
> > diff --git a/drivers/video/pwm_backlight.c
> b/drivers/video/pwm_backlight.c
> > index 46c16a8f44..aa0e292866 100644
> > --- a/drivers/video/pwm_backlight.c
> > +++ b/drivers/video/pwm_backlight.c
> > @@ -14,6 +14,7 @@
> >  #include <pwm.h>
> >  #include <asm/gpio.h>
> >  #include <linux/delay.h>
> > +#include <linux/math64.h>
> >  #include <power/regulator.h>
> >
> >  /**
> > @@ -59,12 +60,14 @@ struct pwm_backlight_priv {
> >
> >  static int set_pwm(struct pwm_backlight_priv *priv)
> >  {
> > +       u64 width;
> >         uint duty_cycle;
> >         int ret;
> >
> >         if (priv->period_ns) {
> > -               duty_cycle = (u64)priv->period_ns * (priv->cur_level -
> priv->min_level) /
> > -                       (priv->max_level - priv->min_level);
> > +               width = priv->period_ns * (priv->cur_level -
> priv->min_level);
> > +               duty_cycle = div_u64(width,
> > +                                    (priv->max_level -
> priv->min_level));
> >                 ret = pwm_set_config(priv->pwm, priv->channel,
> priv->period_ns,
> >                                      duty_cycle);
> >         } else {
> > --
> > 2.41.0
> >
>
> Regards,
> Simon
>

I built U-Boot on a Debian Bookworm container following these steps:

make distclean
> make chromebook_speedy_defconfig
> make -j8


Container is using these gcc and linker versions:

# gcc --version
> gcc (Debian 12.2.0-14) 12.2.0


# ld --version
> GNU ld (GNU Binutils for Debian) 2.40


The error I was getting before the patch is this one:

ld.bfd: error: /usr/lib/gcc/arm-linux-gnueabihf/12/libgcc.a(_udivmoddi4.o)
> uses VFP register arguments, u-boot does not
> ld.bfd: warning:
> /usr/lib/gcc/arm-linux-gnueabihf/12/libgcc.a(_udivmoddi4.o) uses 4-byte
> wchar_t yet the output is to use 2-byte wchar_t; use of wchar_t values
> across objects may fail
> ld.bfd: failed to merge target specific data of file
> /usr/lib/gcc/arm-linux-gnueabihf/12/libgcc.a(_udivmoddi4.o)
> make: *** [Makefile:1764: u-boot] Error 1


Please do tell me if there is any other information I can provide.

-- 
Alvaro F. García
Functional-oriented Software Architect