Re: [PATCH v3 1/7] drm: add drm_print_bits

[Daniel Vetter]

On Mon, Sep 09, 2019 at 02:46:47PM +0200, Thomas Zimmermann wrote:
> 
> 
> Am 04.09.19 um 07:47 schrieb Gerd Hoffmann:
> > New helper to print named bits of some value (think flags fields).
> > 
> > Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> > ---
> >  include/drm/drm_print.h     |  3 +++
> >  drivers/gpu/drm/drm_print.c | 33 +++++++++++++++++++++++++++++++++
> >  2 files changed, 36 insertions(+)
> > 
> > diff --git a/include/drm/drm_print.h b/include/drm/drm_print.h
> > index 112165d3195d..12d4916254b4 100644
> > --- a/include/drm/drm_print.h
> > +++ b/include/drm/drm_print.h
> > @@ -89,6 +89,9 @@ __printf(2, 3)
> >  void drm_printf(struct drm_printer *p, const char *f, ...);
> >  void drm_puts(struct drm_printer *p, const char *str);
> >  void drm_print_regset32(struct drm_printer *p, struct debugfs_regset32 *regset);
> > +void drm_print_bits(struct drm_printer *p,
> > +		    unsigned long value, const char *bits[],
> > +		    unsigned int from, unsigned int to);
> >  
> >  __printf(2, 0)
> >  /**
> > diff --git a/drivers/gpu/drm/drm_print.c b/drivers/gpu/drm/drm_print.c
> > index ad302d71eeee..dfa27367ebb8 100644
> > --- a/drivers/gpu/drm/drm_print.c
> > +++ b/drivers/gpu/drm/drm_print.c
> > @@ -185,6 +185,39 @@ void drm_printf(struct drm_printer *p, const char *f, ...)
> >  }
> >  EXPORT_SYMBOL(drm_printf);
> >  
> > +/**
> > + * drm_print_bits - print bits to a &drm_printer stream
> > + *
> > + * Print bits (in flag fields for example) in human readable form.
> > + * The first name in the @bits array is for the bit indexed by @from.
> > + *
> > + * @p: the &drm_printer
> > + * @value: field value.
> > + * @bits: Array with bit names.
> > + * @from: start of bit range to print (inclusive).
> > + * @to: end of bit range to print (exclusive).

Just an aside: At least in drm we generally but the parameter docs above
the free-flow text.
-Daniel
> > + */
> > +void drm_print_bits(struct drm_printer *p,
> > +		    unsigned long value, const char *bits[],
> > +		    unsigned int from, unsigned int to)
> > +{
> > +	bool first = true;
> > +	unsigned int i;
> > +
> > +	for (i = from; i < to; i++) {
> > +		if (!(value & (1 << i)))
> > +			continue;
> > +		if (WARN_ON_ONCE(!bits[i-from]))
> > +			continue;
> > +		drm_printf(p, "%s%s", first ? "" : ",",
> > +			   bits[i-from]);
> > +		first = false;
> > +	}
> > +	if (first)
> > +		drm_printf(p, "(none)");
> > +}
> > +EXPORT_SYMBOL(drm_print_bits);
> > +
> >  void drm_dev_printk(const struct device *dev, const char *level,
> >  		    const char *format, ...)
> >  {
> > 
> 
> Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> 
> -- 
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Linux GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany
> GF: Felix Imendörffer, Mary Higgins, Sri Rasiah
> HRB 21284 (AG Nürnberg)
> 




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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch