Re: [PATCH 1/3] ARM: i.MX8M: esdctl: limit i.MX8MP early memory size

[Sascha Hauer <sha@pengutronix.de>]

On Wed, Feb 08, 2023 at 09:20:15AM +0100, Sascha Hauer wrote:
> On Mon, Feb 06, 2023 at 10:00:02PM +0100, Lucas Stach wrote:
> > Limit detected early memory size to 1GB on i.MX8MP, as the default DT
> > has a reserved memory region at 0x92400000, which will conflict with
> > our malloc area in some configurations. Until we can properly parse
> > and exclude the reserved memory regions in the PBL, just avoid getting
> > near that DRAM address by limiting the detected size.
> 
> The memory region reserved at 0x92400000 belongs to an audio processing
> DSP. This is unused for sure in barebox, so do we really need to handle
> this case here?
> 
> Besides, who had that glorious of hardcoding that RAM area in the dtsi
                                ^idea

> file?? Is this address dictated by the hardware? That would mean the DSP
> is not usable on machines with only 1GiB of RAM. If it's not dictated
> by the hardware, why is it in the dtsi file?
> 
> This smells fishy.
> 
> Sascha
> 
> > 
> > Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
> > ---
> >  arch/arm/mach-imx/esdctl.c | 12 +++++++++++-
> >  1 file changed, 11 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm/mach-imx/esdctl.c b/arch/arm/mach-imx/esdctl.c
> > index a704250297bb..043de477a77d 100644
> > --- a/arch/arm/mach-imx/esdctl.c
> > +++ b/arch/arm/mach-imx/esdctl.c
> > @@ -947,7 +947,17 @@ void __noreturn imx8mn_barebox_entry(void *boarddata)
> >  
> >  void __noreturn imx8mp_barebox_entry(void *boarddata)
> >  {
> > -	imx8m_barebox_entry(boarddata, 32);
> > +	/*
> > +	 * Limit detected early memory size to 1GB on i.MX8MP, as the default
> > +	 * DT has a reserved memory region at 0x92400000, which will conflict
> > +	 * with our malloc area in some configurations. Until we can properly
> > +	 * parse and exclude the reserved memory regions in the PBL, just avoid
> > +	 * getting near that DRAM address by limiting the detected size.
> > +	 */
> > +	barebox_arm_entry(MX8M_DDR_CSD1_BASE_ADDR,
> > +			  min_t(resource_size_t, SZ_1G,
> > +				imx8m_barebox_earlymem_size(32)),
> > +			  boarddata);
> >  }
> >  
> >  void __noreturn imx8mq_barebox_entry(void *boarddata)
> > -- 
> > 2.39.1
> > 
> > 
> > 
> 
> -- 
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