linux-kernel - Re: [PATCH 1/3] i3c: master: Add inline i3c_master_readsl and i3c_master

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Message-ID: <z6hrfvw3ubkob67k7bvg2qovsxwenh3e76bdtdjgsbnpchniwn@6hxhf3sxynxv>
Date: Sun, 22 Jun 2025 10:43:35 +0200
From: Jorge Marques <gastmaier@...il.com>
To: Frank Li <Frank.li@....com>
Cc: Jorge Marques <jorge.marques@...log.com>, 
	Alexandre Belloni <alexandre.belloni@...tlin.com>, Przemysław Gaj <pgaj@...ence.com>, 
	linux-i3c@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] i3c: master: Add inline i3c_master_readsl and
 i3c_master_writesl

On Fri, Jun 20, 2025 at 02:41:12PM -0400, Frank Li wrote:
> On Fri, Jun 20, 2025 at 06:54:59PM +0200, Jorge Marques wrote:
> > The i3c abstraction excepts u8 buffers, but some controllers have a bus
> > width of 32-bits and don't support flagging valid bytes, so it is
> > required to read/write long words and to use memcpy on the remainder of
> > the number of bytes by 32-bits to not write/read outside the buffer
> > bounds.
> >
> > Signed-off-by: Jorge Marques <jorge.marques@...log.com>
> > ---
> >  include/linux/i3c/master.h | 36 ++++++++++++++++++++++++++++++++++++
> >  1 file changed, 36 insertions(+)
> >
> > diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
> > index c67922ece617d6320c0c7e4838c2e7edda8c19f5..11401f2acb42e4d3a60df33b7c794d8a0360cdc2 100644
> > --- a/include/linux/i3c/master.h
> > +++ b/include/linux/i3c/master.h
> 
> suggest move to drivers/i3c/internals.h becaue only master drivers use it.
> 
Hi Frank,
Ok, also renaming to i3c_writel_fifo() and i3c_readl_fifo() as well
reworking the commit messages.
> > @@ -674,6 +674,42 @@ i3c_master_get_bus(struct i3c_master_controller *master)
> >  	return &master->bus;
> >  }
> >
> > +/**
> > + * i3c_master_writesl- Write bytes to long memory region from byte array
> > + * @addr: Register to write to
> > + * @bytes: Pointer to the data bytes to write
> > + * @nbytes: Number of bytes to write
> > + */
> > +static inline void i3c_master_writesl(void __iomem *addr, const u8 *bytes,
> > +				      int nbytes)
> 
> const void *bytes
> 
Ack.

> > +{
> > +writesl(addr, bytes, nbytes / 4);
> 
> fix indention
> 
> Frank
> 
Ack.

Best regards,
Jorge
> > +	if (nbytes & 3) {
> > +		u32 tmp = 0;
> > +
> > +		memcpy(&tmp, bytes + (nbytes & ~3), nbytes & 3);
> > +		writel(tmp, addr);
> > +	}
> > +}
> > +
> > +/**
> > + * i3c_master_readsl - Read bytes from long memory region to byte array
> > + * @addr: Register to read from
> > + * @bytes: Pointer to the buffer to store read bytes
> > + * @nbytes: Number of bytes to read
> > + */
> > +static inline void i3c_master_readsl(const void __iomem *addr, u8 *bytes,
> > +				     int nbytes)
> > +{
> > +readsl(addr, bytes, nbytes / 4);
> > +	if (nbytes & 3) {
> > +		u32 tmp;
> > +
> > +		tmp = readl(addr);
> > +		memcpy(bytes + (nbytes & ~3), &tmp, nbytes & 3);
> > +	}
> > +}
> > +
> >  struct i3c_generic_ibi_pool;
> >
> >  struct i3c_generic_ibi_pool *
> >
> > --
> > 2.49.0
> >
> >