RE: [PATCH v5 09/10] ARM: sunplus: Add initial support for Sunplus SP7021 SoC

["qinjian[覃健]" <qinjian@cqplus1.com>]

> On Tue, Dec 7, 2021 at 8:21 AM qinjian[覃健] <qinjian@cqplus1.com> wrote:
> > > > @@ -152,6 +152,7 @@ textofs-$(CONFIG_ARCH_MSM8X60) := 0x00208000
> > > >  textofs-$(CONFIG_ARCH_MSM8960) := 0x00208000
> > > >  textofs-$(CONFIG_ARCH_MESON) := 0x00208000
> > > >  textofs-$(CONFIG_ARCH_AXXIA) := 0x00308000
> > > > +textofs-$(CONFIG_ARCH_SUNPLUS) := 0x00308000
> > >
> > > What is this needed for? If it boots without this line, better avoid
> > > adding it, because
> > > it will increase the kernel size for everyone else (unless they also enable
> > > AXXIA).
> > >
> >
> > SP7021 reserved the 1st 1MB memory for ARM926@P-Chip using,
> > The 2nd 1MB memory for IOP device and the 3rd 1MB memory for bootloader.
> > I'll add these comments at next commit.
> 
> I think you can just remove the memory from the system memory map in the
> device tree and pretend it only starts after the bootloader. It's been a while
> since I looked at this though, so I could be misremembering what the minimum
> boundaries are for doing this.
> 
>         Arnd

I have test following 3 methods:

1. current patch
DT:
	memory {
		reg = <0x00000000 0x20000000>; /* 512MB */
	};

	reserved-memory {
		#address-cells = <1>;
		#size-cells = <1>;
		ranges;

		iop_reserve: iop_device {
			no-map;
			reg = <0x00100000 0x00100000>; 
		};
		a926_reserve: a926_memory {
			no-map;
			reg = <0x00000000 0x00100000>;
		};
	};
arch/arm/Makefile:
	textofs-$(CONFIG_ARCH_SUNPLUS) := 0x00308000

bootlog & meminfo :
[    0.000000] Zone ranges:
[    0.000000]   Normal   [mem 0x0000000000000000-0x000000001fffffff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000000000000-0x00000000001fffff]
[    0.000000]   node   0: [mem 0x0000000000200000-0x000000001fffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x000000001fffffff]

~ # cat /proc/meminfo
MemTotal:         514008 kB
MemFree:          491960 kB
MemAvailable:     488608 kB



2. DT same as case 1, but no modify @ arch/arm/Makefile

bootlog & meminfo :
[    0.000000] OF: fdt: Reserved memory: failed to reserve memory for node 'iop_device': base 0x00100000, size 1 MiB
[    0.000000] OF: fdt: Reserved memory: failed to reserve memory for node 'a926_memory': base 0x00000000, size 1 MiB
...
[    0.000000] Zone ranges:
[    0.000000]   Normal   [mem 0x0000000000000000-0x000000001fffffff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000000000000-0x000000001fffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000000000000-0x000000001fffffff]

~ # cat /proc/meminfo
MemTotal:         516056 kB
MemFree:          493928 kB
MemAvailable:     490572 kB



3. DT:
	memory {
		reg = <0x00300000 0x1FD00000>; /* 512 - 3 MB */
	};
no modify @ arch/arm/Makefile

bootlog & meminfo :
[    0.000000] Zone ranges:
[    0.000000]   Normal   [mem 0x0000000000400000-0x000000001fffffff]
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x0000000000400000-0x000000001fffffff]
[    0.000000] Initmem setup node 0 [mem 0x0000000000400000-0x000000001fffffff]

~ # cat /proc/meminfo
MemTotal:         511964 kB
MemFree:          489636 kB
MemAvailable:     486292 kB



I think method 1 should be correct (compare method 2) & better (compare method 3).