Documentation/devicetree/bindings/arm/cci.txt

   1 =======================================================
   2 ARM CCI cache coherent interconnect binding description
   3 =======================================================
   4
   5 ARM multi-cluster systems maintain intra-cluster coherency through a
   6 cache coherent interconnect (CCI) that is capable of monitoring bus
   7 transactions and manage coherency, TLB invalidations and memory barriers.
   8
   9 It allows snooping and distributed virtual memory message broadcast across
  10 clusters, through memory mapped interface, with a global control register
  11 space and multiple sets of interface control registers, one per slave
  12 interface.
  13
  14 Bindings for the CCI node follow the ePAPR standard, available from:
  15
  16 www.power.org/documentation/epapr-version-1-1/
  17
  18 with the addition of the bindings described in this document which are
  19 specific to ARM.
  20
  21 * CCI interconnect node
  22
  23         Description: Describes a CCI cache coherent Interconnect component
  24
  25         Node name must be "cci".
  26         Node's parent must be the root node /, and the address space visible
  27         through the CCI interconnect is the same as the one seen from the
  28         root node (ie from CPUs perspective as per DT standard).
  29         Every CCI node has to define the following properties:
  30
  31         - compatible
  32                 Usage: required
  33                 Value type: <string>
  34                 Definition: must be set to
  35                             "arm,cci-400"
  36
  37         - reg
  38                 Usage: required
  39                 Value type: <prop-encoded-array>
  40                 Definition: A standard property. Specifies base physical
  41                             address of CCI control registers common to all
  42                             interfaces.
  43
  44         - ranges:
  45                 Usage: required
  46                 Value type: <prop-encoded-array>
  47                 Definition: A standard property. Follow rules in the ePAPR for
  48                             hierarchical bus addressing. CCI interfaces
  49                             addresses refer to the parent node addressing
  50                             scheme to declare their register bases.
  51
  52         CCI interconnect node can define the following child nodes:
  53
  54         - CCI control interface nodes
  55
  56                 Node name must be "slave-if".
  57                 Parent node must be CCI interconnect node.
  58
  59                 A CCI control interface node must contain the following
  60                 properties:
  61
  62                 - compatible
  63                         Usage: required
  64                         Value type: <string>
  65                         Definition: must be set to
  66                                     "arm,cci-400-ctrl-if"
  67
  68                 - interface-type:
  69                         Usage: required
  70                         Value type: <string>
  71                         Definition: must be set to one of {"ace", "ace-lite"}
  72                                     depending on the interface type the node
  73                                     represents.
  74
  75                 - reg:
  76                         Usage: required
  77                         Value type: <prop-encoded-array>
  78                         Definition: the base address and size of the
  79                                     corresponding interface programming
  80                                     registers.
  81
  82 * CCI interconnect bus masters
  83
  84         Description: masters in the device tree connected to a CCI port
  85                      (inclusive of CPUs and their cpu nodes).
  86
  87         A CCI interconnect bus master node must contain the following
  88         properties:
  89
  90         - cci-control-port:
  91                 Usage: required
  92                 Value type: <phandle>
  93                 Definition: a phandle containing the CCI control interface node
  94                             the master is connected to.
  95
  96 Example:
  97
  98         cpus {
  99                 #size-cells = <0>;
 100                 #address-cells = <1>;
 101
 102                 CPU0: cpu@0 {
 103                         device_type = "cpu";
 104                         compatible = "arm,cortex-a15";
 105                         cci-control-port = <&cci_control1>;
 106                         reg = <0x0>;
 107                 };
 108
 109                 CPU1: cpu@1 {
 110                         device_type = "cpu";
 111                         compatible = "arm,cortex-a15";
 112                         cci-control-port = <&cci_control1>;
 113                         reg = <0x1>;
 114                 };
 115
 116                 CPU2: cpu@100 {
 117                         device_type = "cpu";
 118                         compatible = "arm,cortex-a7";
 119                         cci-control-port = <&cci_control2>;
 120                         reg = <0x100>;
 121                 };
 122
 123                 CPU3: cpu@101 {
 124                         device_type = "cpu";
 125                         compatible = "arm,cortex-a7";
 126                         cci-control-port = <&cci_control2>;
 127                         reg = <0x101>;
 128                 };
 129
 130         };
 131
 132         dma0: dma@3000000 {
 133                 compatible = "arm,pl330", "arm,primecell";
 134                 cci-control-port = <&cci_control0>;
 135                 reg = <0x0 0x3000000 0x0 0x1000>;
 136                 interrupts = <10>;
 137                 #dma-cells = <1>;
 138                 #dma-channels = <8>;
 139                 #dma-requests = <32>;
 140         };
 141
 142         cci@2c090000 {
 143                 compatible = "arm,cci-400";
 144                 #address-cells = <1>;
 145                 #size-cells = <1>;
 146                 reg = <0x0 0x2c090000 0 0x1000>;
 147                 ranges = <0x0 0x0 0x2c090000 0x6000>;
 148
 149                 cci_control0: slave-if@1000 {
 150                         compatible = "arm,cci-400-ctrl-if";
 151                         interface-type = "ace-lite";
 152                         reg = <0x1000 0x1000>;
 153                 };
 154
 155                 cci_control1: slave-if@4000 {
 156                         compatible = "arm,cci-400-ctrl-if";
 157                         interface-type = "ace";
 158                         reg = <0x4000 0x1000>;
 159                 };
 160
 161                 cci_control2: slave-if@5000 {
 162                         compatible = "arm,cci-400-ctrl-if";
 163                         interface-type = "ace";
 164                         reg = <0x5000 0x1000>;
 165                 };
 166         };
 167
 168 This CCI node corresponds to a CCI component whose control registers sits
 169 at address 0x000000002c090000.
 170 CCI slave interface @0x000000002c091000 is connected to dma controller dma0.
 171 CCI slave interface @0x000000002c094000 is connected to CPUs {CPU0, CPU1};
 172 CCI slave interface @0x000000002c095000 is connected to CPUs {CPU2, CPU3};