[PATCH] s5pv210: Change the base ram address to 0x3000'0000
kmpark at infradead.org
Sun May 30 20:47:39 EDT 2010
On Mon, May 31, 2010 at 9:39 AM, Ben Dooks <ben-linux at fluff.org> wrote:
> On Fri, May 28, 2010 at 11:35:59AM +0900, Kyungmin Park wrote:
>> s5pc110 (aka s5pv210) has 2 DRAM port and used it both usually.
>> Assume DMC0 starts with 0x2000'0000 with 128MiB.
>> DMC1 starts with 0x4000'0000 with 128MiB.
>> Note that DMC1 has to start address 0x4000'0000 at least.
>> Then there's too much memory hole 0x1800'0000 (128MiB + 256MiB)
>> To reduce memory waste, the DMC0 start with 0x3000'0000.
>> Signed-off-by: Kyungmin Park <kyungmin.park at samsung.com>
>> diff --git a/arch/arm/mach-s5pv210/Makefile.boot b/arch/arm/mach-s5pv210/Makefile.boot
>> index ff90aa1..b0909e3 100644
>> --- a/arch/arm/mach-s5pv210/Makefile.boot
>> +++ b/arch/arm/mach-s5pv210/Makefile.boot
>> @@ -1,2 +1,2 @@
>> - zreladdr-y := 0x20008000
>> -params_phys-y := 0x20000100
>> + zreladdr-y := 0x30008000
>> +params_phys-y := 0x30000100
> Apart from the technical comments that have been in this thread, I would
> like to share notes about making changes like these that affect the entire
> SoC kernel build.
> Firstly, changing this effects the rest of the users, not everyone is
> using the same device with same layout. This configuration boots on
> both S5PC110 and S5PV210 devices. Some of these _have_ to support 1GiB
> of memory. Some of them have their bootloaders programemd to start at
> 0x20... So please think of how this will affect everyone else.
> Secondly, if you have thought about point 1, then please let us know in
> the commit messages. The commit message isn't just a log of what the
> patch does, it can also be used to show any necessary working about what
> is happening and side-effects of it.
> Thirdly, the kernel's default configuration for a SoC/arch isn't meant to
> be the best-fit for your board(s) or development practicies. It is meant
> to cover as many devices as possible, to allow build testing and to have
> something that people can test with. If it is not the most efficient on
> the board, then make your own defconfig that is a best fit for your
> So, sometimes when this sort of change is required there may be a case of
> making it configurable so that your own defconfig/boardconfig can select
> it for your own projects.
> Please keep in mind that other people have/are using the kernel and that
> some changes have an affect on other projects as well as your own. This
> is why user-space facing changes are the most debated and difficult to
> do, kernel internals shift quite easily, whilst the data exported to
> userspace is kept as stable as possible.
Definitely I agree with your opinions. and that's why I change it to
when we start the project. chip vendor guides us to use the
0x3000'0000. at that time there's some reason to use this address. As
I know. but some time later they change it to 0x2000'0000.
But we already setup and develop the all environment as 0x3000'0000.
it's also difficult to change it to 0x2000'0000.
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