[PATCH 01/11] imx: implement get_effective_memsize

[Peng Fan]

> Subject: Re: [PATCH 01/11] imx: implement get_effective_memsize
> 
> On Tuesday 08 November 2022 09:38:01 Peng Fan wrote:
> > On 11/7/2022 3:55 PM, Pali Rohár wrote:
> > > On Monday 07 November 2022 16:00:06 Peng Fan (OSS) wrote:
> > > > From: Peng Fan <peng.fan at nxp.com>
> > > >
> > > > To i.MX6/7 which has 2GB memory, the upper 4KB cut off, will cause
> > > > the top 1MB not mapped as normal memory, because ARMV7-A use
> > > > section mapping. So implement i.MX6/7 specific
> > > > get_effective_memsize to fix the issue.
> > > >
> > > > Fixes: 777aaaa706bc("common/memsize.c: Fix get_effective_memsize()
> > > > to check for overflow")
> > > > Signed-off-by: Peng Fan <peng.fan at nxp.com>
> > >
> > > Should not just configuring CONFIG_MAX_MEM_MAPPED properly avoid
> that issue?
> >
> > No, unless I decrease PHYS_SDRAM_SIZE.
> 
> So, what is the issue? I just do not see what happens after 777aaaa706bc
> that RAM size is calculated incorrectly in your case. I did not catch the
> description from commit message. What are your gd->ram_size and
> CONFIG_MAX_MEM_MAPPED values that current code does not work?

The base is 2GB, the size is 2GB. With CONFIG_MAX_MEM_MAPPED,
the ram_size already decreased by 4KB.

Regards,
Peng.

> 
> > Regards,
> > Peng.
> >
> > >
> > > > ---
> > > >   arch/arm/mach-imx/cache.c | 14 ++++++++++++++
> > > >   1 file changed, 14 insertions(+)
> > > >
> > > > diff --git a/arch/arm/mach-imx/cache.c b/arch/arm/mach-imx/cache.c
> > > > index ab9b621a2a6..69a085abee7 100644
> > > > --- a/arch/arm/mach-imx/cache.c
> > > > +++ b/arch/arm/mach-imx/cache.c
> > > > @@ -7,10 +7,24 @@
> > > >   #include <cpu_func.h>
> > > >   #include <asm/armv7.h>
> > > >   #include <asm/cache.h>
> > > > +#include <asm/global_data.h>
> > > >   #include <asm/pl310.h>
> > > >   #include <asm/io.h>
> > > >   #include <asm/mach-imx/sys_proto.h>
> > > > +DECLARE_GLOBAL_DATA_PTR;
> > > > +
> > > > +phys_size_t get_effective_memsize(void) { #ifndef
> > > > +CONFIG_MAX_MEM_MAPPED
> > > > +	return gd->ram_size;
> > > > +#else
> > > > +	/* limit stack to what we can reasonable map */
> > > > +	return ((gd->ram_size > CONFIG_MAX_MEM_MAPPED) ?
> > > > +		CONFIG_MAX_MEM_MAPPED : gd->ram_size); #endif }
> > > > +
> > > >   void enable_ca7_smp(void)
> > > >   {
> > > >   	u32 val;
> > > > --
> > > > 2.36.0
> > > >