diff options
| author | Nicolas Pitre <nico@cam.org> | 2008-09-16 13:05:53 -0400 |
|---|---|---|
| committer | Gary King <GKing@nvidia.com> | 2010-02-02 15:56:15 -0800 |
| commit | 1f62c1e9ba3e2ac33b2dfa4c7b08b7cb2fc3c81e (patch) | |
| tree | daad172d9979fd3cf6bdd98262cb4def88dcf65e /Documentation/arm | |
| parent | ec1c33b802243ea87310b236bad856ddc0dfd8b3 (diff) | |
[ARM] fixmap support
This is the minimum fixmap interface expected to be implemented by
architectures supporting highmem.
We have a second level page table already allocated and covering
0xfff00000-0xffffffff because the exception vector page is located
at 0xffff0000, and various cache tricks already use some entries above
0xffff0000. Therefore the PTEs covering 0xfff00000-0xfffeffff are free
to be used.
However the XScale cache flushing code already uses virtual addresses
between 0xfffe0000 and 0xfffeffff.
So this reserves the 0xfff00000-0xfffdffff range for fixmap stuff.
The Documentation/arm/memory.txt information is updated accordingly,
including the information about the actual top of DMA memory mapping
region which didn't match the code.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Diffstat (limited to 'Documentation/arm')
| -rw-r--r-- | Documentation/arm/memory.txt | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/Documentation/arm/memory.txt b/Documentation/arm/memory.txt index dc6045577a8b..43cb1004d35f 100644 --- a/Documentation/arm/memory.txt +++ b/Documentation/arm/memory.txt @@ -29,7 +29,14 @@ ffff0000 ffff0fff CPU vector page. CPU supports vector relocation (control register V bit.) -ffc00000 fffeffff DMA memory mapping region. Memory returned +fffe0000 fffeffff XScale cache flush area. This is used + in proc-xscale.S to flush the whole data + cache. Free for other usage on non-XScale. + +fff00000 fffdffff Fixmap mapping region. Addresses provided + by fix_to_virt() will be located here. + +ffc00000 ffefffff DMA memory mapping region. Memory returned by the dma_alloc_xxx functions will be dynamically mapped here. |