On Tue, Jan 25, 2011 at 11:17 AM, Mitsutaka Amano
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On Tue, Jan 25, 2011 at 11:05 AM, tiejun.chen [off-list ref]=

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Mitsutaka Amano wrote:

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On Mon, Jan 24, 2011 at 3:48 PM, tiejun.chen <tiejun.chen@windriver.com=

wrote:

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Mitsutaka Amano wrote:

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Hi all,

I'm testing the ppc platform is based on mpc85xx. 256MB Flash memory
has been installed. Then I found this entries.

/proc/vmallocinfo
~~~
0xc9100000-0xd9101000 268439552 of_flash_probe+0x290/0x814 ioremap

physmap_of allocated 268MB over to the vmalloc. vmalloc space is tigh=

t.

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Why does we need mpc platforms to flash memory allocation? I know

This should not be dedicated to so-called mpc platform. And we always =

use

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ioremap() to map the device space. And on PPC ioremap also use the sam=

e space as

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vmalloc(). While bootstrap you also can see this associated message li=

ke the

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follows,
------
......
=A0* 0xd1000000..0xffbe9000 =A0: vmalloc & ioremap

Yeah. My platform says the follow message.

=A0 * 0xc9000000..0xdf000000 =A0: vmalloc & ioremap

Any reason why you don't access > 0xdf000000?

Higher than 0xdf000000 has to map TLB for using other peripherals.
it's 400MB over.

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The default vmalloc & ioremap space was about 200MB. so I increased
that by decreasing lowmem.
But If possible, I hope to keep default maps. So I don't want to use
vmalloc & ioremap

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other architectures don't allocate to the vmalloc.
The design of the hardware? or Is there the way to use the flash

You can open /dev/mem then mmap() with a appropriate offset to access =

the device

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space including flash.

I use the device tree(dts) and define flash partitions. Also I use CFI
driver and CFI_PHYSMAP_OF for device tree.
Is there the reference driver in what uses mmap() kernel tree? I think
I have to write a driver what can support dts and mmap() with a
appropriate offset to access the device.

You should not write anything again. And you can access any physical add=

ress

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directly via /dev/mem from the user space like the following:

fd =3D open(/dev/mem,);
mmap(fd + offset);

Thanks for letting me know. I want to use in combination with device
tree. So I'll write a driver based on physmap_of.c(such as mmap_of.c)

I confused and misunderstand that. it has to use as a rootfs. so It
can't use a userland program.
Of cource, it can be force mapping to the userspace. but system will
be unstable. I think.

Mitsutaka

Thanks,
Mitsutaka

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Tiejun

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Thanks,
Mitsutaka

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Tiejun

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memory without vmalloc?

Thanks,
Mitsutaka