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authorVitaly Wool <vwool@ru.mvista.com>2006-11-20 16:32:39 +0300
committerPaul Mackerras <paulus@samba.org>2006-12-04 20:41:24 +1100
commit28f9ec349ae47c91768b7bc5607db4442c818e11 (patch)
tree548d75d56ffefd80c8c0fc85afd39fad2d3f156f /Documentation
parenta5715d6dfc85e002bfad68bb2858cf5a248e2060 (diff)
downloadleg-kernel-28f9ec349ae47c91768b7bc5607db4442c818e11.tar.gz
[POWERPC] Add of_platform support for ROM devices
This adds support for flash device descriptions to the OF device tree. It's inspired by and partially borrowed from Sergei's patch "[RFC] Adding MTD to device tree.patch". Signed-off-by: Vitaly Wool <vwool@ru.mvista.com> Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/powerpc/booting-without-of.txt39
1 files changed, 39 insertions, 0 deletions
diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt
index 4ac2d641fcb6..b3bd36668db3 100644
--- a/Documentation/powerpc/booting-without-of.txt
+++ b/Documentation/powerpc/booting-without-of.txt
@@ -6,6 +6,8 @@
IBM Corp.
(c) 2005 Becky Bruce <becky.bruce at freescale.com>,
Freescale Semiconductor, FSL SOC and 32-bit additions
+(c) 2006 MontaVista Software, Inc.
+ Flash chip node definition
May 18, 2005: Rev 0.1 - Initial draft, no chapter III yet.
@@ -1693,6 +1695,43 @@ platforms are moved over to use the flattened-device-tree model.
};
};
+ g) Flash chip nodes
+
+ Flash chips (Memory Technology Devices) are often used for solid state
+ file systems on embedded devices.
+
+ Required properties:
+
+ - device_type : has to be "rom"
+ - compatible : Should specify what this ROM device is compatible with
+ (i.e. "onenand"). Currently, this is most likely to be "direct-mapped"
+ (which corresponds to the MTD physmap mapping driver).
+ - regs : Offset and length of the register set (or memory mapping) for
+ the device.
+
+ Recommended properties :
+
+ - bank-width : Width of the flash data bus in bytes. Required
+ for the NOR flashes (compatible == "direct-mapped" and others) ONLY.
+ - partitions : Several pairs of 32-bit values where the first value is
+ partition's offset from the start of the device and the second one is
+ partition size in bytes with LSB used to signify a read only
+ partititon (so, the parition size should always be an even number).
+ - partition-names : The list of concatenated zero terminated strings
+ representing the partition names.
+
+ Example:
+
+ flash@ff000000 {
+ device_type = "rom";
+ compatible = "direct-mapped";
+ regs = <ff000000 01000000>;
+ bank-width = <4>;
+ partitions = <00000000 00f80000
+ 00f80000 00080001>;
+ partition-names = "fs\0firmware";
+ };
+
More devices will be defined as this spec matures.