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Re: Dma addr should use Kuseg1 for MIPS32?

To: figo zhang <figo1802@gmail.com>
Subject: Re: Dma addr should use Kuseg1 for MIPS32?
From: zhangfx <zhangfx@lemote.com>
Date: Mon, 07 Dec 2009 21:30:51 +0800
Cc: wuzhangjin@gmail.com, linux-mips@linux-mips.org, rostedt@goodmis.org
In-reply-to: <c6ed1ac50912062352u227c28e1me2107dbf7bd8a0ea@mail.gmail.com>
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physical address (address comes out of the CPU bus to memory) can be different with bus address(used by DMA) in MIPS boards.

figo zhang 写道:
hi,

I am writing a driver for MIPS32. i wirte this code for DMA addr:

dma_vaddr =(char*) __get_free_pages(GFP_KERNEL|GFP_DMA, order);
dma_phy = virt_to_phy(dma_vaddr);

i write dma_phy to DMA base register, but why it cannot work? it should write Kseg1 space to DMA register?
I remember that it is ok for ARM/X86 .


Best,
Figo.zhang

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