0001 Keystone Navigator DMA Controller
0002
0003 This document explains the device tree bindings for the packet dma
0004 on keystone devices. The Keystone Navigator DMA driver sets up the dma
0005 channels and flows for the QMSS(Queue Manager SubSystem) who triggers
0006 the actual data movements across clients using destination queues. Every
0007 client modules like NETCP(Network Coprocessor), SRIO(Serial Rapid IO),
0008 CRYPTO Engines etc has its own instance of dma hardware. QMSS has also
0009 an internal packet DMA module which is used as an infrastructure DMA
0010 with zero copy.
0011
0012 Navigator DMA cloud layout:
0013 ------------------
0014 | Navigator DMAs |
0015 ------------------
0016 |
0017 |-> DMA instance #0
0018 |
0019 |-> DMA instance #1
0020 .
0021 .
0022 |
0023 |-> DMA instance #n
0024
0025 Navigator DMA properties:
0026 Required properties:
0027 - compatible: Should be "ti,keystone-navigator-dma"
0028 - clocks: phandle to dma instances clocks. The clock handles can be as
0029 many as the dma instances. The order should be maintained as per
0030 the dma instances.
0031 - ti,navigator-cloud-address: Should contain base address for the multi-core
0032 navigator cloud and number of addresses depends on SOC integration
0033 configuration.. Navigator cloud global address needs to be programmed
0034 into DMA and the DMA uses it as the physical addresses to reach queue
0035 managers. Note that these addresses though points to queue managers,
0036 they are relevant only from DMA perspective. The QMSS may not choose to
0037 use them since it has a different address space view to reach all
0038 its components.
0039
0040 DMA instance properties:
0041 Required properties:
0042 - reg: Should contain register location and length of the following dma
0043 register regions. Register regions should be specified in the following
0044 order.
0045 - Global control register region (global).
0046 - Tx DMA channel configuration register region (txchan).
0047 - Rx DMA channel configuration register region (rxchan).
0048 - Tx DMA channel Scheduler configuration register region (txsched).
0049 - Rx DMA flow configuration register region (rxflow).
0050
0051 Optional properties:
0052 - reg-names: Names for the register regions.
0053 - ti,enable-all: Enable all DMA channels vs clients opening specific channels
0054 what they need. This property is useful for the userspace fast path
0055 case where the linux drivers enables the channels used by userland
0056 stack.
0057 - ti,loop-back: To loopback Tx streaming I/F to Rx streaming I/F. Used for
0058 infrastructure transfers.
0059 - ti,rx-retry-timeout: Number of dma cycles to wait before retry on buffer
0060 starvation.
0061
0062 Example:
0063
0064 knav_dmas: knav_dmas@0 {
0065 compatible = "ti,keystone-navigator-dma";
0066 clocks = <&papllclk>, <&clkxge>;
0067 #address-cells = <1>;
0068 #size-cells = <1>;
0069 ranges;
0070 ti,navigator-cloud-address = <0x23a80000 0x23a90000
0071 0x23aa0000 0x23ab0000>;
0072
0073 dma_gbe: dma_gbe@0 {
0074 reg = <0x2004000 0x100>,
0075 <0x2004400 0x120>,
0076 <0x2004800 0x300>,
0077 <0x2004c00 0x120>,
0078 <0x2005000 0x400>;
0079 reg-names = "global", "txchan", "rxchan",
0080 "txsched", "rxflow";
0081 };
0082
0083 dma_xgbe: dma_xgbe@0 {
0084 reg = <0x2fa1000 0x100>,
0085 <0x2fa1400 0x200>,
0086 <0x2fa1800 0x200>,
0087 <0x2fa1c00 0x200>,
0088 <0x2fa2000 0x400>;
0089 reg-names = "global", "txchan", "rxchan",
0090 "txsched", "rxflow";
0091 };
0092 };
0093
0094 Navigator DMA client:
0095 Required properties:
0096 - ti,navigator-dmas: List of one or more DMA specifiers, each consisting of
0097 - A phandle pointing to DMA instance node
0098 - A DMA channel number as a phandle arg.
0099 - ti,navigator-dma-names: Contains dma channel name for each DMA specifier in
0100 the 'ti,navigator-dmas' property.
0101
0102 Example:
0103
0104 netcp: netcp@2090000 {
0105 ..
0106 ti,navigator-dmas = <&dma_gbe 22>,
0107 <&dma_gbe 23>,
0108 <&dma_gbe 8>;
0109 ti,navigator-dma-names = "netrx0", "netrx1", "nettx";
0110 ..
0111 };
