[PATCH 4/6] pstore/ram: Add some more documentation and examples

[Anton Vorontsov]

Suggested-by: Shuah Khan <shuahkhan@xxxxxxxxx>
Signed-off-by: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx>
---
 Documentation/ramoops.txt |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/Documentation/ramoops.txt b/Documentation/ramoops.txt
index 4ba7db2..138823b 100644
--- a/Documentation/ramoops.txt
+++ b/Documentation/ramoops.txt
@@ -40,6 +40,12 @@ corrupt, but usually it is restorable.
 Setting the ramoops parameters can be done in 2 different manners:
  1. Use the module parameters (which have the names of the variables described
  as before).
+ For quick debugging, you can also reserve parts of memory during boot
+ and then use the reserved memory for ramoops. For example, assuming a machine
+ with > 128 MB of memory, the following kernel command line will tell the
+ kernel to use only the first 128 MB of memory, and place ECC-protected ramoops
+ region at 128 MB boundary:
+ "mem=128M ramoops.mem_address=0x8000000 ramoops.ecc=1"
  2. Use a platform device and set the platform data. The parameters can then
  be set through that platform data. An example of doing that is:
 
@@ -70,6 +76,15 @@ if (ret) {
 	return ret;
 }
 
+You can specify either RAM memory or peripheral devices' memory. However, when
+specifying RAM, be sure to reserve the memory by issuing memblock_reserve()
+very early in the architecture code, just before platform device registration,
+e.g.:
+
+#include <linux/memblock.h>
+
+memblock_reserve(ramoops_data.mem_address, ramoops_data.mem_size);
+
 3. Dump format
 
 The data dump begins with a header, currently defined as "====" followed by a
-- 
1.7.9.2

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