[U-Boot] [PATCH] armv8/fsl-layerscape: add IFC fixup for LS1043A with QSPI enabled

[Prabhakar Kushwaha]

> -----Original Message-----
> From: U-Boot [mailto:u-boot-bounces at lists.denx.de] On Behalf Of Qianyu
> Gong
> Sent: Friday, March 11, 2016 3:49 PM
> To: Scott Wood <oss at buserror.net>; u-boot at lists.denx.de; york sun
> <york.sun at nxp.com>
> Cc: Mingkai Hu <mingkai.hu at nxp.com>
> Subject: Re: [U-Boot] [PATCH] armv8/fsl-layerscape: add IFC fixup for
> LS1043A with QSPI enabled
> 
> Hi Scott,
> 
> > -----Original Message-----
> > From: Scott Wood [mailto:oss at buserror.net]
> > Sent: Tuesday, February 23, 2016 8:12 AM
> > To: Qianyu Gong <qianyu.gong at nxp.com>; u-boot at lists.denx.de; york
> sun
> > <york.sun at nxp.com>
> > Cc: Mingkai Hu <mingkai.hu at nxp.com>
> > Subject: Re: [PATCH] armv8/fsl-layerscape: add IFC fixup for LS1043A
> > with QSPI enabled
> >
> > On Mon, 2016-02-22 at 18:05 +0800, Gong Qianyu wrote:
> > > QSPI and IFC are pin-multiplexed on LS1043A. So if QSPI is enabled,
> > > IFC should be disabled.
> > > But just disable IFC driver in LS1043A Linux is not enough because
> > > mdio-mux will access IFC address space -- actually it accesses FPGA
> > > which is connected to IFC CS3. So disable the whole IFC node in
> > > Linux device tree.
> > >
> > > Signed-off-by: Gong Qianyu <Qianyu.Gong at nxp.com>
> > >
> > > diff --git a/arch/arm/cpu/armv8/fsl-layerscape/fdt.c
> > > b/arch/arm/cpu/armv8/fsl-layerscape/fdt.c
> > > index 4e4861d..5bb3048 100644
> > > --- a/arch/arm/cpu/armv8/fsl-layerscape/fdt.c
> > > +++ b/arch/arm/cpu/armv8/fsl-layerscape/fdt.c
> > > @@ -204,4 +204,11 @@ void ft_cpu_setup(void *blob, bd_t *bd)  #ifdef
> > > CONFIG_FSL_LSCH3
> > >  	fdt_fixup_smmu(blob);
> > >  #endif
> > > +
> > > +#ifdef CONFIG_LS1043A
> > > +#ifdef CONFIG_FSL_QSPI
> > > +	do_fixup_by_compat(blob, "fsl,ifc",
> > > +			   "status", "disabled", 8 + 1, 1); #endif #endif
> > >  }
> >
> > This muxing is done at runtime, right?  It isn't a case of the board
> > hardwiring one or the other?  In that case, it should be handled at
> > runtime here as well.  At a minimum, allow the user to use hwconfig to
> > choose which they want to be accessible.  Ideally there would be
> > something in the device tree to list the reason(s) for a device being
> > disabled, so the OS knows it can regard the device as being enabled if it
> knows about and enables them all.
> >
> > -Scott
> 
> Sorry for the late reply. We have been asking the silicon team for the details
> of the pin muxing these days.
> The conclusion is that all IFC interfaces(cs0/cs1/cs2) are disabled as long as
> QSPI is enabled on LS1043AQDS board.
> As I know, this muxing won't be handled in kernel. Since IFC is disabled in U-
> Boot, IFC node would better be disabled in kernel as well.
> Also in such cases, users have no other choice.
> 

This may not be always true.  

 In LS1088A, IFC-FPGA is available during QSPI boot.

--prabhakar