tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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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 or "mtd-ram".
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
20For JEDEC compatible devices, the following additional properties
21are defined:
22
23 - vendor-id : Contains the flash chip's vendor id (1 byte).
24 - device-id : Contains the flash chip's device id (1 byte).
25
26The device tree may optionally contain sub-nodes describing partitions of the
27address space. See partition.txt for more detail.
28
29Example:
30
31 flash@ff000000 {
32 compatible = "amd,am29lv128ml", "cfi-flash";
33 reg = <ff000000 01000000>;
34 bank-width = <4>;
35 device-width = <1>;
36 #address-cells = <1>;
37 #size-cells = <1>;
38 fs@0 {
39 label = "fs";
40 reg = <0 f80000>;
41 };
42 firmware@f80000 {
43 label ="firmware";
44 reg = <f80000 80000>;
45 read-only;
46 };
47 };
48
49Here an example with multiple "reg" tuples:
50
51 flash@f0000000,0 {
52 #address-cells = <1>;
53 #size-cells = <1>;
54 compatible = "intel,PC48F4400P0VB", "cfi-flash";
55 reg = <0 0x00000000 0x02000000
56 0 0x02000000 0x02000000>;
57 bank-width = <2>;
58 partition@0 {
59 label = "test-part1";
60 reg = <0 0x04000000>;
61 };
62 };
63
64An example using SRAM:
65
66 sram@2,0 {
67 compatible = "samsung,k6f1616u6a", "mtd-ram";
68 reg = <2 0 0x00200000>;
69 bank-width = <2>;
70 };
71