Re: [PATCH 1/4] ucc_geth: Change private immrbar_virt_to_phys to generic iopa

On Feb 8, 2007, at 1:36 AM, Li Yang-r58472 wrote:

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-----Original Message-----
From: Kumar Gala [mailto:galak@kernel.crashing.org]
Sent: Thursday, February 08, 2007 3:16 PM
To: Li Yang-r58472
Cc: Tabi Timur-B04825; netdev@vger.kernel.org; linuxppc- 
dev@ozlabs.org
Subject: Re: [PATCH 1/4] ucc_geth: Change private  
immrbar_virt_to_phys

to generic

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iopa


On Feb 8, 2007, at 1:06 AM, Li Yang-r58472 wrote:

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MURAM is a mmio region so it don't share the characteristic of

main

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memory that phy_addr = virt_addr - PAGE_OFFSET.  While they can
both be
mapped through page table using iopa().

Right, so when do you know if you'll be using MURAM or normal
memory?  Why not just keep around a token that is the physical
address at the point you make the decision of MURAM vs normal

memory.

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Yes, that can be a way.  But as the virt to phy mapping is only used
once, it's nothing bad to do it this way.

The problem as I stated before with using iopa() is that its not
supported across platforms.

Yes, it is only for PPC32.  But we don't have another API to do  
it.  How
about make it more generic to add PPC64 version?

Why do you need another API to do this, you already have the  
information you want, its just a matter of you keeping track of it.

- k