1
2 * Marvell MBus
3
4 Required properties:
5
6 - compatible: Should be set to one of the following:
7 marvell,armada370-mbus
8 marvell,armadaxp-mbus
9 marvell,armada375-mbus
10 marvell,armada380-mbus
11 marvell,kirkwood-mbus
12 marvell,dove-mbus
13 marvell,orion5x-88f5281-mbus
14 marvell,orion5x-88f5182-mbus
15 marvell,orion5x-88f5181-mbus
16 marvell,orion5x-88f6183-mbus
17 marvell,mv78xx0-mbus
18
19 - address-cells: Must be '2'. The first cell for the MBus ID encoding,
20 the second cell for the address offset within the window.
21
22 - size-cells: Must be '1'.
23
24 - ranges: Must be set up to provide a proper translation for each child.
25 See the examples below.
26
27 - controller: Contains a single phandle referring to the MBus controller
28 node. This allows to specify the node that contains the
29 registers that control the MBus, which is typically contained
30 within the internal register window (see below).
31
32 Optional properties:
33
34 - pcie-mem-aperture: This optional property contains the aperture for
35 the memory region of the PCIe driver.
36 If it's defined, it must encode the base address and
37 size for the address decoding windows allocated for
38 the PCIe memory region.
39
40 - pcie-io-aperture: Just as explained for the above property, this
41 optional property contains the aperture for the
42 I/O region of the PCIe driver.
43
44 * Marvell MBus controller
45
46 Required properties:
47
48 - compatible: Should be set to "marvell,mbus-controller".
49
50 - reg: Device's register space.
51 Two or three entries are expected (see the examples below):
52 the first one controls the devices decoding window,
53 the second one controls the SDRAM decoding window and
54 the third controls the MBus bridge (only with the
55 marvell,armada370-mbus and marvell,armadaxp-mbus
56 compatible strings)
57
58 Example:
59
60 soc {
61 compatible = "marvell,armada370-mbus", "simple-bus";
62 #address-cells = <2>;
63 #size-cells = <1>;
64 controller = <&mbusc>;
65 pcie-mem-aperture = <0xe0000000 0x8000000>;
66 pcie-io-aperture = <0xe8000000 0x100000>;
67
68 internal-regs {
69 compatible = "simple-bus";
70
71 mbusc: mbus-controller@20000 {
72 compatible = "marvell,mbus-controller";
73 reg = <0x20000 0x100>, <0x20180 0x20>, <0x20250 0x8>;
74 };
75
76 /* more children ...*/
77 };
78 };
79
80 ** MBus address decoding window specification
81
82 The MBus children address space is comprised of two cells: the first one for
83 the window ID and the second one for the offset within the window.
84 In order to allow to describe valid and non-valid window entries, the
85 following encoding is used:
86
87 0xSIAA0000 0x00oooooo
88
89 Where:
90
91 S = 0x0 for a MBus valid window
92 S = 0xf for a non-valid window (see below)
93
94 If S = 0x0, then:
95
96 I = 4-bit window target ID
97 AA = windpw attribute
98
99 If S = 0xf, then:
100
101 I = don't care
102 AA = 1 for internal register
103
104 Following the above encoding, for each ranges entry for a MBus valid window
105 (S = 0x0), an address decoding window is allocated. On the other side,
106 entries for translation that do not correspond to valid windows (S = 0xf)
107 are skipped.
108
109 soc {
110 compatible = "marvell,armada370-mbus", "simple-bus";
111 #address-cells = <2>;
112 #size-cells = <1>;
113 controller = <&mbusc>;
114
115 ranges = <0xf0010000 0 0 0xd0000000 0x100000
116 0x01e00000 0 0 0xfff00000 0x100000>;
117
118 bootrom {
119 compatible = "marvell,bootrom";
120 reg = <0x01e00000 0 0x100000>;
121 };
122
123 /* other children */
124 ...
125
126 internal-regs {
127 compatible = "simple-bus";
128 ranges = <0 0xf0010000 0 0x100000>;
129
130 mbusc: mbus-controller@20000 {
131 compatible = "marvell,mbus-controller";
132 reg = <0x20000 0x100>, <0x20180 0x20>, <0x20250 0x8>;
133 };
134
135 /* more children ...*/
136 };
137 };
138
139 In the shown example, the translation entry in the 'ranges' property is what
140 makes the MBus driver create a static decoding window for the corresponding
141 given child device. Note that the binding does not require child nodes to be
142 present. Of course, child nodes are needed to probe the devices.
143
144 Since each window is identified by its target ID and attribute ID there's
145 a special macro that can be use to simplify the translation entries:
146
147 #define MBUS_ID(target,attributes) (((target) << 24) | ((attributes) << 16))
148
149 Using this macro, the above example would be:
150
151 soc {
152 compatible = "marvell,armada370-mbus", "simple-bus";
153 #address-cells = <2>;
154 #size-cells = <1>;
155 controller = <&mbusc>;
156
157 ranges = < MBUS_ID(0xf0, 0x01) 0 0 0xd0000000 0x100000
158 MBUS_ID(0x01, 0xe0) 0 0 0xfff00000 0x100000>;
159
160 bootrom {
161 compatible = "marvell,bootrom";
162 reg = <MBUS_ID(0x01, 0xe0) 0 0x100000>;
163 };
164
165 /* other children */
166 ...
167
168 internal-regs {
169 compatible = "simple-bus";
170 #address-cells = <1>;
171 #size-cells = <1>;
172 ranges = <0 MBUS_ID(0xf0, 0x01) 0 0x100000>;
173
174 mbusc: mbus-controller@20000 {
175 compatible = "marvell,mbus-controller";
176 reg = <0x20000 0x100>, <0x20180 0x20>, <0x20250 0x8>;
177 };
178
179 /* other children */
180 ...
181 };
182 };
183
184
185 ** About the window base address
186
187 Remember the MBus controller allows a great deal of flexibility for choosing
188 the decoding window base address. When planning the device tree layout it's
189 possible to choose any address as the base address, provided of course there's
190 a region large enough available, and with the required alignment.
191
192 Yet in other words: there's nothing preventing us from setting a base address
193 of 0xf0000000, or 0xd0000000 for the NOR device shown above, if such region is
194 unused.
195
196 ** Window allocation policy
197
198 The mbus-node ranges property defines a set of mbus windows that are expected
199 to be set by the operating system and that are guaranteed to be free of overlaps
200 with one another or with the system memory ranges.
201
202 Each entry in the property refers to exactly one window. If the operating system
203 chooses to use a different set of mbus windows, it must ensure that any address
204 translations performed from downstream devices are adapted accordingly.
205
206 The operating system may insert additional mbus windows that do not conflict
207 with the ones listed in the ranges, e.g. for mapping PCIe devices.
208 As a special case, the internal register window must be set up by the boot
209 loader at the address listed in the ranges property, since access to that region
210 is needed to set up the other windows.
211
212 ** Example
213
214 See the example below, where a more complete device tree is shown:
215
216 soc {
217 compatible = "marvell,armadaxp-mbus", "simple-bus";
218 controller = <&mbusc>;
219
220 ranges = <MBUS_ID(0xf0, 0x01) 0 0 0xd0000000 0x100000 /* internal-regs */
221 MBUS_ID(0x01, 0x1d) 0 0 0xfff00000 0x100000
222 MBUS_ID(0x01, 0x2f) 0 0 0xf0000000 0x8000000>;
223
224 bootrom {
225 compatible = "marvell,bootrom";
226 reg = <MBUS_ID(0x01, 0x1d) 0 0x100000>;
227 };
228
229 devbus-bootcs {
230 ranges = <0 MBUS_ID(0x01, 0x2f) 0 0x8000000>;
231
232 /* NOR */
233 nor {
234 compatible = "cfi-flash";
235 reg = <0 0x8000000>;
236 bank-width = <2>;
237 };
238 };
239
240 pcie-controller {
241 compatible = "marvell,armada-xp-pcie";
242 device_type = "pci";
243
244 #address-cells = <3>;
245 #size-cells = <2>;
246
247 ranges =
248 <0x82000000 0 0x40000 MBUS_ID(0xf0, 0x01) 0x40000 0 0x00002000 /* Port 0.0 registers */
249 0x82000000 0 0x42000 MBUS_ID(0xf0, 0x01) 0x42000 0 0x00002000 /* Port 2.0 registers */
250 0x82000000 0 0x44000 MBUS_ID(0xf0, 0x01) 0x44000 0 0x00002000 /* Port 0.1 registers */
251 0x82000000 0 0x48000 MBUS_ID(0xf0, 0x01) 0x48000 0 0x00002000 /* Port 0.2 registers */
252 0x82000000 0 0x4c000 MBUS_ID(0xf0, 0x01) 0x4c000 0 0x00002000 /* Port 0.3 registers */
253 0x82000800 0 0xe0000000 MBUS_ID(0x04, 0xe8) 0xe0000000 0 0x08000000 /* Port 0.0 MEM */
254 0x81000800 0 0 MBUS_ID(0x04, 0xe0) 0xe8000000 0 0x00100000 /* Port 0.0 IO */>;
255
256
257 pcie@1,0 {
258 /* Port 0, Lane 0 */
259 };
260 };
261
262 internal-regs {
263 compatible = "simple-bus";
264 #address-cells = <1>;
265 #size-cells = <1>;
266 ranges = <0 MBUS_ID(0xf0, 0x01) 0 0x100000>;
267
268 mbusc: mbus-controller@20000 {
269 reg = <0x20000 0x100>, <0x20180 0x20>, <0x20250 0x8>;
270 };
271
272 interrupt-controller@20000 {
273 reg = <0x20a00 0x2d0>, <0x21070 0x58>;
274 };
275 };
276 };
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