On 06/25/2013 12:46:40 PM, Leif Lindholm wrote:
This patch provides documentation of the early_ioremap()
functionality,
including its implementation and usage instructions.
Signed-off-by: Leif Lindholm <leif.lindholm@xxxxxxxxxx>
---
Documentation/arm/00-INDEX | 2 ++
Documentation/arm/early_ioremap.txt | 12 ++++++++++++
2 files changed, 14 insertions(+)
create mode 100644 Documentation/arm/early_ioremap.txt
diff --git a/Documentation/arm/00-INDEX b/Documentation/arm/00-INDEX
index 36420e1..4978456 100644
--- a/Documentation/arm/00-INDEX
+++ b/Documentation/arm/00-INDEX
@@ -24,6 +24,8 @@ SPEAr
- ST SPEAr platform Linux Overview
VFP/
- Release notes for Linux Kernel Vector Floating Point support
code
+early_ioremap.txt
+ - documentation of the early_ioremap() functionality
empeg/
- Ltd's Empeg MP3 Car Audio Player
mem_alignment
diff --git a/Documentation/arm/early_ioremap.txt
b/Documentation/arm/early_ioremap.txt
new file mode 100644
index 0000000..178f791
--- /dev/null
+++ b/Documentation/arm/early_ioremap.txt
@@ -0,0 +1,12 @@
+early_ioremap() and early_iounmap() rovide a mechanism for
temporarily mapping
Typo: provide
+in small blocks of memory, identified by their physical address,
into the
+fixmap virtual address block before paging_init() has been called
and more
+flexible mapping functions are available.
+
+Due to its direct method, it also gets around potential need for
special
+handling of regions that end up in highmem.
+
+It supports up to 7 simultaneously mapped regions of up to 128KB
each.
+All regions are mapped as non-shareable device memory.
+
+Specify 'early_ioremap_debug' on the kernel commandline for verbose
output.
--
1.7.10.4
Minor quibble: this explains what it does, but nothing about how to use
it. Do these mappings persist if you don't unmap them, or does
paging_init() clear them?
Oh well:
Acked-by: Rob Landley <rob@xxxxxxxxxxx>
Rob--
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