diff options
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/powerpc/booting-without-of.txt | 39 | ||||
-rw-r--r-- | Documentation/powerpc/mpc52xx-device-tree-bindings.txt | 189 |
2 files changed, 228 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 | ||
diff --git a/Documentation/powerpc/mpc52xx-device-tree-bindings.txt b/Documentation/powerpc/mpc52xx-device-tree-bindings.txt new file mode 100644 index 000000000000..d077d764f82b --- /dev/null +++ b/Documentation/powerpc/mpc52xx-device-tree-bindings.txt | |||
@@ -0,0 +1,189 @@ | |||
1 | MPC52xx Device Tree Bindings | ||
2 | ---------------------------- | ||
3 | |||
4 | (c) 2006 Secret Lab Technologies Ltd | ||
5 | Grant Likely <grant.likely at secretlab.ca> | ||
6 | |||
7 | I - Introduction | ||
8 | ================ | ||
9 | Boards supported by the arch/powerpc architecture require device tree be | ||
10 | passed by the boot loader to the kernel at boot time. The device tree | ||
11 | describes what devices are present on the board and how they are | ||
12 | connected. The device tree can either be passed as a binary blob (as | ||
13 | described in Documentation/powerpc/booting-without-of.txt), or passed | ||
14 | by Open Firmare (IEEE 1275) compatible firmware using an OF compatible | ||
15 | client interface API. | ||
16 | |||
17 | This document specifies the requirements on the device-tree for mpc52xx | ||
18 | based boards. These requirements are above and beyond the details | ||
19 | specified in either the OpenFirmware spec or booting-without-of.txt | ||
20 | |||
21 | All new mpc52xx-based boards are expected to match this document. In | ||
22 | cases where this document is not sufficient to support a new board port, | ||
23 | this document should be updated as part of adding the new board support. | ||
24 | |||
25 | II - Philosophy | ||
26 | =============== | ||
27 | The core of this document is naming convention. The whole point of | ||
28 | defining this convention is to reduce or eliminate the number of | ||
29 | special cases required to support a 52xx board. If all 52xx boards | ||
30 | follow the same convention, then generic 52xx support code will work | ||
31 | rather than coding special cases for each new board. | ||
32 | |||
33 | This section tries to capture the thought process behind why the naming | ||
34 | convention is what it is. | ||
35 | |||
36 | 1. Node names | ||
37 | ------------- | ||
38 | There is strong convention/requirements already established for children | ||
39 | of the root node. 'cpus' describes the processor cores, 'memory' | ||
40 | describes memory, and 'chosen' provides boot configuration. Other nodes | ||
41 | are added to describe devices attached to the processor local bus. | ||
42 | Following convention already established with other system-on-chip | ||
43 | processors, MPC52xx boards must have an 'soc5200' node as a child of the | ||
44 | root node. | ||
45 | |||
46 | The soc5200 node holds child nodes for all on chip devices. Child nodes | ||
47 | are typically named after the configured function. ie. the FEC node is | ||
48 | named 'ethernet', and a PSC in uart mode is named 'serial'. | ||
49 | |||
50 | 2. device_type property | ||
51 | ----------------------- | ||
52 | similar to the node name convention above; the device_type reflects the | ||
53 | configured function of a device. ie. 'serial' for a uart and 'spi' for | ||
54 | an spi controller. However, while node names *should* reflect the | ||
55 | configured function, device_type *must* match the configured function | ||
56 | exactly. | ||
57 | |||
58 | 3. compatible property | ||
59 | ---------------------- | ||
60 | Since device_type isn't enough to match devices to drivers, there also | ||
61 | needs to be a naming convention for the compatible property. Compatible | ||
62 | is an list of device descriptions sorted from specific to generic. For | ||
63 | the mpc52xx, the required format for each compatible value is | ||
64 | <chip>-<device>[-<mode>]. At the minimum, the list shall contain two | ||
65 | items; the first specifying the exact chip, and the second specifying | ||
66 | mpc52xx for the chip. | ||
67 | |||
68 | ie. ethernet on mpc5200b: compatible = "mpc5200b-ethernet\0mpc52xx-ethernet" | ||
69 | |||
70 | The idea here is that most drivers will match to the most generic field | ||
71 | in the compatible list (mpc52xx-*), but can also test the more specific | ||
72 | field for enabling bug fixes or extra features. | ||
73 | |||
74 | Modal devices, like PSCs, also append the configured function to the | ||
75 | end of the compatible field. ie. A PSC in i2s mode would specify | ||
76 | "mpc52xx-psc-i2s", not "mpc52xx-i2s". This convention is chosen to | ||
77 | avoid naming conflicts with non-psc devices providing the same | ||
78 | function. For example, "mpc52xx-spi" and "mpc52xx-psc-spi" describe | ||
79 | the mpc5200 simple spi device and a PSC spi mode respectively. | ||
80 | |||
81 | If the soc device is more generic and present on other SOCs, the | ||
82 | compatible property can specify the more generic device type also. | ||
83 | |||
84 | ie. mscan: compatible = "mpc5200-mscan\0mpc52xx-mscan\0fsl,mscan"; | ||
85 | |||
86 | At the time of writing, exact chip may be either 'mpc5200' or | ||
87 | 'mpc5200b'. | ||
88 | |||
89 | Device drivers should always try to match as generically as possible. | ||
90 | |||
91 | III - Structure | ||
92 | =============== | ||
93 | The device tree for an mpc52xx board follows the structure defined in | ||
94 | booting-without-of.txt with the following additional notes: | ||
95 | |||
96 | 0) the root node | ||
97 | ---------------- | ||
98 | Typical root description node; see booting-without-of | ||
99 | |||
100 | 1) The cpus node | ||
101 | ---------------- | ||
102 | The cpus node follows the basic layout described in booting-without-of. | ||
103 | The bus-frequency property holds the XLB bus frequency | ||
104 | The clock-frequency property holds the core frequency | ||
105 | |||
106 | 2) The memory node | ||
107 | ------------------ | ||
108 | Typical memory description node; see booting-without-of. | ||
109 | |||
110 | 3) The soc5200 node | ||
111 | ------------------- | ||
112 | This node describes the on chip SOC peripherals. Every mpc52xx based | ||
113 | board will have this node, and as such there is a common naming | ||
114 | convention for SOC devices. | ||
115 | |||
116 | Required properties: | ||
117 | name type description | ||
118 | ---- ---- ----------- | ||
119 | device_type string must be "soc" | ||
120 | ranges int should be <0 baseaddr baseaddr+10000> | ||
121 | reg int must be <baseaddr 10000> | ||
122 | |||
123 | Recommended properties: | ||
124 | name type description | ||
125 | ---- ---- ----------- | ||
126 | compatible string should be "<chip>-soc\0mpc52xx-soc" | ||
127 | ie. "mpc5200b-soc\0mpc52xx-soc" | ||
128 | #interrupt-cells int must be <3>. If it is not defined | ||
129 | here then it must be defined in every | ||
130 | soc device node. | ||
131 | bus-frequency int IPB bus frequency in HZ. Clock rate | ||
132 | used by most of the soc devices. | ||
133 | Defining it here avoids needing it | ||
134 | added to every device node. | ||
135 | |||
136 | 4) soc5200 child nodes | ||
137 | ---------------------- | ||
138 | Any on chip SOC devices available to Linux must appear as soc5200 child nodes. | ||
139 | |||
140 | Note: in the tables below, '*' matches all <chip> values. ie. | ||
141 | *-pic would translate to "mpc5200-pic\0mpc52xx-pic" | ||
142 | |||
143 | Required soc5200 child nodes: | ||
144 | name device_type compatible Description | ||
145 | ---- ----------- ---------- ----------- | ||
146 | cdm@<addr> cdm *-cmd Clock Distribution | ||
147 | pic@<addr> interrupt-controller *-pic need an interrupt | ||
148 | controller to boot | ||
149 | bestcomm@<addr> dma-controller *-bestcomm 52xx pic also requires | ||
150 | the bestcomm device | ||
151 | |||
152 | Recommended soc5200 child nodes; populate as needed for your board | ||
153 | name device_type compatible Description | ||
154 | ---- ----------- ---------- ----------- | ||
155 | gpt@<addr> gpt *-gpt General purpose timers | ||
156 | rtc@<addr> rtc *-rtc Real time clock | ||
157 | mscan@<addr> mscan *-mscan CAN bus controller | ||
158 | pci@<addr> pci *-pci PCI bridge | ||
159 | serial@<addr> serial *-psc-uart PSC in serial mode | ||
160 | i2s@<addr> i2s *-psc-i2s PSC in i2s mode | ||
161 | ac97@<addr> ac97 *-psc-ac97 PSC in ac97 mode | ||
162 | spi@<addr> spi *-psc-spi PSC in spi mode | ||
163 | irda@<addr> irda *-psc-irda PSC in IrDA mode | ||
164 | spi@<addr> spi *-spi MPC52xx spi device | ||
165 | ethernet@<addr> network *-fec MPC52xx ethernet device | ||
166 | ata@<addr> ata *-ata IDE ATA interface | ||
167 | i2c@<addr> i2c *-i2c I2C controller | ||
168 | usb@<addr> usb-ohci-be *-ohci,ohci-be USB controller | ||
169 | xlb@<addr> xlb *-xlb XLB arbritrator | ||
170 | |||
171 | IV - Extra Notes | ||
172 | ================ | ||
173 | |||
174 | 1. Interrupt mapping | ||
175 | -------------------- | ||
176 | The mpc52xx pic driver splits hardware IRQ numbers into two levels. The | ||
177 | split reflects the layout of the PIC hardware itself, which groups | ||
178 | interrupts into one of three groups; CRIT, MAIN or PERP. Also, the | ||
179 | Bestcomm dma engine has it's own set of interrupt sources which are | ||
180 | cascaded off of peripheral interrupt 0, which the driver interprets as a | ||
181 | fourth group, SDMA. | ||
182 | |||
183 | The interrupts property for device nodes using the mpc52xx pic consists | ||
184 | of three cells; <L1 L2 level> | ||
185 | |||
186 | L1 := [CRIT=0, MAIN=1, PERP=2, SDMA=3] | ||
187 | L2 := interrupt number; directly mapped from the value in the | ||
188 | "ICTL PerStat, MainStat, CritStat Encoded Register" | ||
189 | level := [LEVEL_HIGH=0, EDGE_RISING=1, EDGE_FALLING=2, LEVEL_LOW=3] | ||