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authorVitaly Wool <vwool@ru.mvista.com>2006-11-20 08:32:39 -0500
committerPaul Mackerras <paulus@samba.org>2006-12-04 04:41:24 -0500
commit28f9ec349ae47c91768b7bc5607db4442c818e11 (patch)
tree548d75d56ffefd80c8c0fc85afd39fad2d3f156f /Documentation/powerpc
parenta5715d6dfc85e002bfad68bb2858cf5a248e2060 (diff)
[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/powerpc')
-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 @@
6 IBM Corp. 6 IBM Corp.
7(c) 2005 Becky Bruce <becky.bruce at freescale.com>, 7(c) 2005 Becky Bruce <becky.bruce at freescale.com>,
8 Freescale Semiconductor, FSL SOC and 32-bit additions 8 Freescale Semiconductor, FSL SOC and 32-bit additions
9(c) 2006 MontaVista Software, Inc.
10 Flash chip node definition
9 11
10 May 18, 2005: Rev 0.1 - Initial draft, no chapter III yet. 12 May 18, 2005: Rev 0.1 - Initial draft, no chapter III yet.
11 13
@@ -1693,6 +1695,43 @@ platforms are moved over to use the flattened-device-tree model.
1693 }; 1695 };
1694 }; 1696 };
1695 1697
1698 g) Flash chip nodes
1699
1700 Flash chips (Memory Technology Devices) are often used for solid state
1701 file systems on embedded devices.
1702
1703 Required properties:
1704
1705 - device_type : has to be "rom"
1706 - compatible : Should specify what this ROM device is compatible with
1707 (i.e. "onenand"). Currently, this is most likely to be "direct-mapped"
1708 (which corresponds to the MTD physmap mapping driver).
1709 - regs : Offset and length of the register set (or memory mapping) for
1710 the device.
1711
1712 Recommended properties :
1713
1714 - bank-width : Width of the flash data bus in bytes. Required
1715 for the NOR flashes (compatible == "direct-mapped" and others) ONLY.
1716 - partitions : Several pairs of 32-bit values where the first value is
1717 partition's offset from the start of the device and the second one is
1718 partition size in bytes with LSB used to signify a read only
1719 partititon (so, the parition size should always be an even number).
1720 - partition-names : The list of concatenated zero terminated strings
1721 representing the partition names.
1722
1723 Example:
1724
1725 flash@ff000000 {
1726 device_type = "rom";
1727 compatible = "direct-mapped";
1728 regs = <ff000000 01000000>;
1729 bank-width = <4>;
1730 partitions = <00000000 00f80000
1731 00f80000 00080001>;
1732 partition-names = "fs\0firmware";
1733 };
1734
1696 More devices will be defined as this spec matures. 1735 More devices will be defined as this spec matures.
1697 1736
1698 1737