[U-Boot] [PATCH 00/27] Clean up address mapping functions & CONFIG_SYS_SDRAM_BASE

[Masahiro Yamada]

Hi Paul,

2016-10-01 23:19 GMT+09:00 Paul Burton <paul.burton at imgtec.com>:
> README states that CONFIG_SYS_SDRAM_BASE should be the physical address
> of the base of SDRAM memory. This is expected by some code such as the
> PCI layer, which uses CONFIG_SYS_SDRAM_BASE to set up a region for
> system memory. Other code such as the image loading code used by bootm
> or the generic board_f.c expect CONFIG_SYS_SDRAM_BASE to be directly
> accessible by the CPU, which necessitates that it be a virtual address.
>
> Where virtual & physical addresses aren't identity mapped, as is the
> case for MIPS, we cannot possibly satisfy both. Until now MIPS has used
> a virtual CONFIG_SYS_SDRAM_BASE. This series fixes up the mess by doing
> a few things:
>
>   - Ensuring that we provide virt_to_phys() on all architectures.
>
>   - Fixing code that expects to use CONFIG_SYS_SDRAM_BASE as a virtual
>     address to instead convert it to a physical address using
>     virt_to_phys().
>
>   - Converts MIPS code & all MIPS boards to provide a physical
>     CONFIG_SYS_SDRAM_BASE, which typically is zero.
>


Thanks for working on this.

As you may notice, include/linux/io.h defines
the generic implementation of ioremap().

(It is guarded by #ifndef CONFIG_HAVE_ARCH_IOREMAP
so that MIPS can work-around it.)

If you go with asm-generic/io.h,
perhaps should we be consistent, that is,
move the generic ioremap() to asm-generic/io.h?

We do not have to do it in this series,
but it would be appreciated
if you volunteer to make it in a better way.


Thanks,

-- 
Best Regards
Masahiro Yamada