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From: Trevor Woerner <ppc339@vtnet.ca>
To: linuxppc-dev@lists.linuxppc.org
Subject: address translation
Date: Thu, 15 May 2003 07:29:36 -0400	[thread overview]
Message-ID: <200305150729.36436.ppc339@vtnet.ca> (raw)


I want to setup a mapping so that when anything tries to read/write the
16 bytes at 0x1f0 - 0x1ff the actual physical memory that gets accessed
is 0xf7000000 - 0xf700000f.

I can't figure out what I need to call to get this done.

ioremap() is the exact opposite of what I want.

remap_page_range() comes very close but aligns everything to the page
boundary. In other words, after I do the mapping with either 0x1f0 or
0x0 as the virtual address, accessing 0x1f0 gives me 0xf70001f0 instead
of 0xf7000000. I don't want *page* translation, I need
*address-for-address* translation (if such a thing is possible). I
tried setting the physical address to 0xf7000000 - 0x1f0 but that
didn't work (I didn't think it would :-)

I think resetting _IO_BASE is just another page translation trick.

I also tried using io_block_mapping(), which I use in my platform io
setup routine, but the MMU crashed with one of those '###A' reports.

any suggestions, please?

        Trevor

** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/

             reply	other threads:[~2003-05-15 11:29 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-05-15 11:29 Trevor Woerner [this message]
2003-05-15 11:46 ` address translation Gary Thomas
2003-05-16  3:13   ` Trevor Woerner
2003-05-15 12:13 ` Magnus Damm
2003-05-16  3:14   ` Trevor Woerner
2003-05-15 14:05 ` Benjamin Herrenschmidt
2003-05-16  4:02   ` Trevor Woerner
2003-05-16  8:35     ` Geert Uytterhoeven
2003-05-16  9:00     ` Benjamin Herrenschmidt
  -- strict thread matches above, loose matches on Subject: below --
2003-05-15  3:50 Trevor Woerner

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