Re: [PATCH] airoha: rework RAM size handling to support multiple RAM size

[Christian Marangi <ansuelsmth@gmail.com>]

On Thu, Jul 24, 2025 at 01:30:45PM +0300, Mikhail Kshevetskiy wrote:
> 
> On 22.07.2025 21:44, Christian Marangi wrote:
> > There are multiple version of the same reference board with different
> > RAM size and it's not enough to base the RAM size entirely from DT. To
> > better support it use the get_ram_size way to scan for the actual RAM
> > size of Airoha SoC and increase the size of the memory map.
> >
> > Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
> > ---
> >  arch/arm/mach-airoha/an7581/init.c | 23 +++++++++++++++++++----
> >  1 file changed, 19 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/arm/mach-airoha/an7581/init.c b/arch/arm/mach-airoha/an7581/init.c
> > index d149e0ee3c8..0f72365c4ab 100644
> > --- a/arch/arm/mach-airoha/an7581/init.c
> > +++ b/arch/arm/mach-airoha/an7581/init.c
> > @@ -2,10 +2,14 @@
> >  
> >  #include <fdtdec.h>
> >  #include <init.h>
> > +#include <linux/sizes.h>
> >  #include <sysreset.h>
> >  #include <asm/armv8/mmu.h>
> > +#include <asm/global_data.h>
> >  #include <asm/system.h>
> >  
> > +DECLARE_GLOBAL_DATA_PTR;
> > +
> >  int print_cpuinfo(void)
> >  {
> >  	printf("CPU:   Airoha AN7581\n");
> > @@ -14,12 +18,23 @@ int print_cpuinfo(void)
> >  
> >  int dram_init(void)
> >  {
> > -	return fdtdec_setup_mem_size_base();
> > +	int ret;
> > +
> > +	ret = fdtdec_setup_mem_size_base();
> > +	if (ret)
> > +		return ret;
> > +
> > +	gd->ram_size = get_ram_size((void *)gd->ram_base, SZ_8G);
> 
> Can we use a memory size passed by airoha trusted firmware instead of
> playing with  get_ram_size()?
>

Hi I received some feedback from Airoha about this and sadly it's not
possible. There are too much version of ATF and only some of them
provide RAM size in some way or another. Also there isn't an exact HW
trap to read to know the RAM size hence raw testing the ram and not
depending externally is the only solution :(

I will address all the other comments.

> > +
> > +	return 0;
> >  }
> >  
> >  int dram_init_banksize(void)
> >  {
> > -	return fdtdec_setup_memory_banksize();
> > +	gd->bd->bi_dram[0].start = gd->ram_base;
> > +	gd->bd->bi_dram[0].size = gd->ram_size;
> as I know u-boot can safely use only 2Gb of memory, thus it's better
> 
>         #define CFG_MAX_MEM_MAPPED  SZ_2G
> 
> and replace above line with
> 
>         gd->bd->bi_dram[0].size = get_effective_memsize();
> 
> > +
> > +	return 0;
> >  }
> >  
> >  void reset_cpu(void)
> > @@ -32,12 +47,12 @@ static struct mm_region an7581_mem_map[] = {
> >  		/* DDR */
> >  		.virt = 0x80000000UL,
> >  		.phys = 0x80000000UL,
> > -		.size = 0x80000000UL,
> > +		.size = 0x200000000ULL,
> >  		.attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) | PTE_BLOCK_OUTER_SHARE,
> >  	}, {
> >  		.virt = 0x00000000UL,
> >  		.phys = 0x00000000UL,
> > -		.size = 0x20000000UL,
> > +		.size = 0x40000000UL,
> >  		.attrs = PTE_BLOCK_MEMTYPE(MT_DEVICE_NGNRNE) |
> >  			 PTE_BLOCK_NON_SHARE |
> >  			 PTE_BLOCK_PXN | PTE_BLOCK_UXN

-- 
	Ansuel