[PATCH] mmc: fsl_esdhc: actually enable cache snooping on mpc830x

[Y.b. Lu]

> -----Original Message-----
> From: Peng Fan <peng.fan at nxp.com>
> Sent: Wednesday, February 5, 2020 3:08 PM
> To: Rasmus Villemoes <rasmus.villemoes at prevas.dk>; u-boot at lists.denx.de;
> Y.b. Lu <yangbo.lu at nxp.com>
> Cc: Mario Six <mario.six at gdsys.cc>
> Subject: RE: [PATCH] mmc: fsl_esdhc: actually enable cache snooping on
> mpc830x
> 
> > Subject: [PATCH] mmc: fsl_esdhc: actually enable cache snooping on
> mpc830x
> 
> + Y.b
> 
> Are you ok with this patch?

The mpc830x is old Freescale PowerPC platforms I don't have.
But I agree the fix-up.

Reviewed-by: Yangbo Lu <yangbo.lu at nxp.com>

> 
> Thanks,
> Peng.
> 
> >
> > The reference manuals for MPC8308 and MPC8309 both say that the
> esdhcctl
> > aka DMA Control Register "is implemented as SDHCCR" in the System
> > configuration registers. Unfortunately, that doesn't mean that the registers
> are
> > just mirrors of each other - any write to esdhcctl is simply ignored. So to
> > actually enable cache snooping, we unfortunately have to add a little
> > ifdeffery.
> >
> > There is, naturally, no description of the bit fields of esdhcctl in the MPC8309
> > manual, but comparing the description of esdhcctl from the LS1021A
> > reference manual to the description of the sdhccr in MPC8309, one also finds
> > that the fields are bit-reversed, so the bit to set is
> > 0x02000000 rather than 0x00000040 - this is also what board_mmc_init()
> > uses in the two gdsys/mpc8308/ boards.
> >
> > Signed-off-by: Rasmus Villemoes <rasmus.villemoes at prevas.dk>
> > ---
> >  drivers/mmc/fsl_esdhc.c | 15 +++++++++++++--
> >  1 file changed, 13 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c index
> > 1e7d606cd8..34e5bd270f 100644
> > --- a/drivers/mmc/fsl_esdhc.c
> > +++ b/drivers/mmc/fsl_esdhc.c
> > @@ -577,6 +577,18 @@ static int esdhc_set_ios_common(struct
> > fsl_esdhc_priv *priv, struct mmc *mmc)
> >  	return 0;
> >  }
> >
> > +static void esdhc_enable_cache_snooping(struct fsl_esdhc *regs) {
> > +#ifdef CONFIG_ARCH_MPC830X
> > +	immap_t *immr = (immap_t *)CONFIG_SYS_IMMR;
> > +	sysconf83xx_t *sysconf = &immr->sysconf;
> > +
> > +	setbits_be32(&sysconf->sdhccr, 0x02000000); #else
> > +	esdhc_write32(&regs->esdhcctl, 0x00000040); #endif }
> > +
> >  static int esdhc_init_common(struct fsl_esdhc_priv *priv, struct mmc
> *mmc)
> > {
> >  	struct fsl_esdhc *regs = priv->esdhc_regs; @@ -592,8 +604,7 @@ static
> > int esdhc_init_common(struct fsl_esdhc_priv *priv, struct mmc *mmc)
> >  			return -ETIMEDOUT;
> >  	}
> >
> > -	/* Enable cache snooping */
> > -	esdhc_write32(&regs->esdhcctl, 0x00000040);
> > +	esdhc_enable_cache_snooping(regs);
> >
> >  	esdhc_setbits32(&regs->sysctl, SYSCTL_HCKEN | SYSCTL_IPGEN);
> >
> > --
> > 2.23.0