Re: [PATCH 1/3] ALSA: hda: Fix compilation of snd_hdac_adsp_xxx() helpers

[Takashi Iwai <tiwai@xxxxxxx>]

On Thu, 09 Jan 2025 13:42:18 +0100,
Jaroslav Kysela wrote:
> 
> On 09. 01. 25 13:52, Cezary Rojewski wrote:
> > The snd_hdac_adsp_xxx() wrap snd_hdac_reg_xxx() helpers to simplify
> > register access for AudioDSP drivers e.g.: the avs-driver. Byte- and
> > word-variants of said helps do not expand to bare readx/writex()
> > operations but functions instead and, due to pointer type
> > incompatibility, cause compilation to fail.
> > 
> > As AudioDSP drivers e.g.: the avs-driver utilize struct hda_bus (and
> > thus struct hdac_bus) as the base structure, add casts to address the
> > problem.
> > 
> > Fixes: c19bd02e9029 ("ALSA: hda: Add helper macros for DSP capable devices")
> > Signed-off-by: Cezary Rojewski <cezary.rojewski@xxxxxxxxx>
> > ---
> >   include/sound/hdaudio_ext.h | 16 ++++++++--------
> >   1 file changed, 8 insertions(+), 8 deletions(-)
> > 
> > diff --git a/include/sound/hdaudio_ext.h b/include/sound/hdaudio_ext.h
> > index 957295364a5e..79a010dd0062 100644
> > --- a/include/sound/hdaudio_ext.h
> > +++ b/include/sound/hdaudio_ext.h
> > @@ -120,21 +120,21 @@ int snd_hdac_ext_bus_link_put(struct hdac_bus *bus, struct hdac_ext_link *hlink)
> >   void snd_hdac_ext_bus_link_power(struct hdac_device *codec, bool enable);
> >     #define snd_hdac_adsp_writeb(chip, reg, value) \
> > -	snd_hdac_reg_writeb(chip, (chip)->dsp_ba + (reg), value)
> > +	snd_hdac_reg_writeb((struct hdac_bus *)(chip), (chip)->dsp_ba + (reg), value)
> >   #define snd_hdac_adsp_readb(chip, reg) \
> > -	snd_hdac_reg_readb(chip, (chip)->dsp_ba + (reg))
> > +	snd_hdac_reg_readb((struct hdac_bus *)(chip), (chip)->dsp_ba + (reg))
> >   #define snd_hdac_adsp_writew(chip, reg, value) \
> > -	snd_hdac_reg_writew(chip, (chip)->dsp_ba + (reg), value)
> > +	snd_hdac_reg_writew((struct hdac_bus *)(chip), (chip)->dsp_ba + (reg), value)
> >   #define snd_hdac_adsp_readw(chip, reg) \
> > -	snd_hdac_reg_readw(chip, (chip)->dsp_ba + (reg))
> > +	snd_hdac_reg_readw((struct hdac_bus *)(chip), (chip)->dsp_ba + (reg))
> >   #define snd_hdac_adsp_writel(chip, reg, value) \
> > -	snd_hdac_reg_writel(chip, (chip)->dsp_ba + (reg), value)
> > +	snd_hdac_reg_writel((struct hdac_bus *)(chip), (chip)->dsp_ba + (reg), value)
> >   #define snd_hdac_adsp_readl(chip, reg) \
> > -	snd_hdac_reg_readl(chip, (chip)->dsp_ba + (reg))
> > +	snd_hdac_reg_readl((struct hdac_bus *)(chip), (chip)->dsp_ba + (reg))
> >   #define snd_hdac_adsp_writeq(chip, reg, value) \
> > -	snd_hdac_reg_writeq(chip, (chip)->dsp_ba + (reg), value)
> > +	snd_hdac_reg_writeq((struct hdac_bus *)(chip), (chip)->dsp_ba + (reg), value)
> >   #define snd_hdac_adsp_readq(chip, reg) \
> > -	snd_hdac_reg_readq(chip, (chip)->dsp_ba + (reg))
> > +	snd_hdac_reg_readq((struct hdac_bus *)(chip), (chip)->dsp_ba + (reg))
> >     #define snd_hdac_adsp_updateb(chip, reg, mask, val) \
> >   	snd_hdac_adsp_writeb(chip, reg, \
> 
> 
> I'm not sure, if this change is wanted. The passed pointer validation
> from the compiler side is lost with retyping.
> 
> Perhaps, it would be better to create another set of defines for other
> structure pointers.

Agreed.  The cast there secretly assumes the type punning and it hides
potential bugs.

As those macros are used only by AVS for now, you can move to AVS
locally and redefine for the more appropriate types, too.


thanks,

Takashi