1CFI or JEDEC memory-mapped NOR flash, MTD-RAM (NVRAM...)
2
3Flash chips (Memory Technology Devices) are often used for solid state
4file systems on embedded devices.
5
6 - compatible : should contain the specific model of mtd chip(s)
7   used, if known, followed by either "cfi-flash", "jedec-flash",
8   "mtd-ram" or "mtd-rom".
9 - reg : Address range(s) of the mtd chip(s)
10   It's possible to (optionally) define multiple "reg" tuples so that
11   non-identical chips can be described in one node.
12 - bank-width : Width (in bytes) of the bank.  Equal to the
13   device width times the number of interleaved chips.
14 - device-width : (optional) Width of a single mtd chip.  If
15   omitted, assumed to be equal to 'bank-width'.
16 - #address-cells, #size-cells : Must be present if the device has
17   sub-nodes representing partitions (see below).  In this case
18   both #address-cells and #size-cells must be equal to 1.
19 - no-unaligned-direct-access: boolean to disable the default direct
20   mapping of the flash.
21   On some platforms (e.g. MPC5200) a direct 1:1 mapping may cause
22   problems with JFFS2 usage, as the local bus (LPB) doesn't support
23   unaligned accesses as implemented in the JFFS2 code via memcpy().
24   By defining "no-unaligned-direct-access", the flash will not be
25   exposed directly to the MTD users (e.g. JFFS2) any more.
26 - linux,mtd-name: allow to specify the mtd name for retro capability with
27   physmap-flash drivers as boot loader pass the mtd partition via the old
28   device name physmap-flash.
29 - use-advanced-sector-protection: boolean to enable support for the
30   advanced sector protection (Spansion: PPB - Persistent Protection
31   Bits) locking.
32
33For JEDEC compatible devices, the following additional properties
34are defined:
35
36 - vendor-id : Contains the flash chip's vendor id (1 byte).
37 - device-id : Contains the flash chip's device id (1 byte).
38
39For ROM compatible devices (and ROM fallback from cfi-flash), the following
40additional (optional) property is defined:
41
42 - erase-size : The chip's physical erase block size in bytes.
43
44The device tree may optionally contain sub-nodes describing partitions of the
45address space. See partition.txt for more detail.
46
47Example:
48
49	flash@ff000000 {
50		compatible = "amd,am29lv128ml", "cfi-flash";
51		reg = <ff000000 01000000>;
52		bank-width = <4>;
53		device-width = <1>;
54		#address-cells = <1>;
55		#size-cells = <1>;
56		fs@0 {
57			label = "fs";
58			reg = <0 f80000>;
59		};
60		firmware@f80000 {
61			label ="firmware";
62			reg = <f80000 80000>;
63			read-only;
64		};
65	};
66
67Here an example with multiple "reg" tuples:
68
69	flash@f0000000,0 {
70		#address-cells = <1>;
71		#size-cells = <1>;
72		compatible = "intel,pc48f4400p0vb", "cfi-flash";
73		reg = <0 0x00000000 0x02000000
74		       0 0x02000000 0x02000000>;
75		bank-width = <2>;
76		partition@0 {
77			label = "test-part1";
78			reg = <0 0x04000000>;
79		};
80	};
81
82An example using SRAM:
83
84	sram@2,0 {
85		compatible = "samsung,k6f1616u6a", "mtd-ram";
86		reg = <2 0 0x00200000>;
87		bank-width = <2>;
88	};
89