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Commit Graph

2 Commits

Author SHA1 Message Date
Keith Packard
8d5c6603c4 io mapping: improve documentation
Impact: add documentation

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-03 18:21:44 +01:00
Keith Packard
9663f2e6a6 resources: add io-mapping functions to dynamically map large device apertures
Impact: add new generic io_map_*() APIs

Graphics devices have large PCI apertures which would consume a significant
fraction of a 32-bit address space if mapped during driver initialization.
Using ioremap at runtime is impractical as it is too slow.

This new set of interfaces uses atomic mappings on 32-bit processors and a
large static mapping on 64-bit processors to provide reasonable 32-bit
performance and optimal 64-bit performance.

The current implementation sits atop the io_map_atomic fixmap-based
mechanism for 32-bit processors.

This includes some editorial suggestions from Randy Dunlap for
Documentation/io-mapping.txt

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-31 10:12:39 +01:00