g) Freescale SOC SEC Security Engines
h) Board Control and Status (BCSR)
i) Freescale QUICC Engine module (QE)
- j) Flash chip nodes
+ j) CFI or JEDEC memory-mapped NOR flash
k) Global Utilities Block
+ l) Xilinx IP cores
VII - Specifying interrupt information for devices
1) interrupts property
/cpus/PowerPC,970FX@0
/cpus/PowerPC,970FX@1
(unit addresses do not require leading zeroes)
- - d-cache-line-size : one cell, L1 data cache line size in bytes
- - i-cache-line-size : one cell, L1 instruction cache line size in
+ - d-cache-block-size : one cell, L1 data cache block size in bytes (*)
+ - i-cache-block-size : one cell, L1 instruction cache block size in
bytes
- d-cache-size : one cell, size of L1 data cache in bytes
- i-cache-size : one cell, size of L1 instruction cache in bytes
+(*) The cache "block" size is the size on which the cache management
+instructions operate. Historically, this document used the cache
+"line" size here which is incorrect. The kernel will prefer the cache
+block size and will fallback to cache line size for backward
+compatibility.
+
Recommended properties:
- timebase-frequency : a cell indicating the frequency of the
for the above, the common code doesn't use that property, but
you are welcome to re-use the pSeries or Maple one. A future
kernel version might provide a common function for this.
+ - d-cache-line-size : one cell, L1 data cache line size in bytes
+ if different from the block size
+ - i-cache-line-size : one cell, L1 instruction cache line size in
+ bytes if different from the block size
You are welcome to add any property you find relevant to your board,
like some information about the mechanism used to soft-reset the
i) Freescale QUICC Engine module (QE)
This represents qe module that is installed on PowerQUICC II Pro.
- Hopefully it will merge backward compatibility with CPM/CPM2.
+
+ NOTE: This is an interim binding; it should be updated to fit
+ in with the CPM binding later in this document.
+
Basically, it is a bus of devices, that could act more or less
as a complete entity (UCC, USB etc ). All of them should be siblings on
the "root" qe node, using the common properties from there.
Required properties:
- device_type : should be "spi".
- compatible : should be "fsl_spi".
- - mode : the SPI operation mode, it can be "cpu" or "qe".
+ - mode : the SPI operation mode, it can be "cpu" or "cpu-qe".
- reg : Offset and length of the register set for the device
- interrupts : <a b> where a is the interrupt number and b is a
field that represents an encoding of the sense and level
MAC addresses passed by the firmware when no information other
than indices is available to associate an address with a device.
- phy-connection-type : a string naming the controller/PHY interface type,
- i.e., "mii" (default), "rmii", "gmii", "rgmii", "rgmii-id", "tbi",
- or "rtbi".
+ i.e., "mii" (default), "rmii", "gmii", "rgmii", "rgmii-id" (Internal
+ Delay), "rgmii-txid" (delay on TX only), "rgmii-rxid" (delay on RX only),
+ "tbi", or "rtbi".
Example:
ucc@2000 {
};
};
- j) Flash chip nodes
+ j) CFI or JEDEC memory-mapped NOR flash
Flash chips (Memory Technology Devices) are often used for solid state
file systems on embedded devices.
- Required properties:
-
- - device_type : has to be "rom"
- - compatible : Should specify what this flash device is compatible with.
- Currently, this is most likely to be "direct-mapped" (which
- corresponds to the MTD physmap mapping driver).
- - reg : Offset and length of the register set (or memory mapping) for
- the device.
- - bank-width : Width of the flash data bus in bytes. Required
- for the NOR flashes (compatible == "direct-mapped" and others) ONLY.
-
- Recommended properties :
-
- - partitions : Several pairs of 32-bit values where the first value is
- partition's offset from the start of the device and the second one is
- partition size in bytes with LSB used to signify a read only
- partition (so, the partition size should always be an even number).
- - partition-names : The list of concatenated zero terminated strings
- representing the partition names.
- - probe-type : The type of probe which should be done for the chip
- (JEDEC vs CFI actually). Valid ONLY for NOR flashes.
+ - compatible : should contain the specific model of flash chip(s)
+ used, if known, followed by either "cfi-flash" or "jedec-flash"
+ - reg : Address range of the flash chip
+ - bank-width : Width (in bytes) of the flash bank. Equal to the
+ device width times the number of interleaved chips.
+ - device-width : (optional) Width of a single flash chip. If
+ omitted, assumed to be equal to 'bank-width'.
+ - #address-cells, #size-cells : Must be present if the flash has
+ sub-nodes representing partitions (see below). In this case
+ both #address-cells and #size-cells must be equal to 1.
+
+ For JEDEC compatible devices, the following additional properties
+ are defined:
+
+ - vendor-id : Contains the flash chip's vendor id (1 byte).
+ - device-id : Contains the flash chip's device id (1 byte).
+
+ In addition to the information on the flash bank itself, the
+ device tree may optionally contain additional information
+ describing partitions of the flash address space. This can be
+ used on platforms which have strong conventions about which
+ portions of the flash are used for what purposes, but which don't
+ use an on-flash partition table such as RedBoot.
+
+ Each partition is represented as a sub-node of the flash device.
+ Each node's name represents the name of the corresponding
+ partition of the flash device.
+
+ Flash partitions
+ - reg : The partition's offset and size within the flash bank.
+ - label : (optional) The label / name for this flash partition.
+ If omitted, the label is taken from the node name (excluding
+ the unit address).
+ - read-only : (optional) This parameter, if present, is a hint to
+ Linux that this flash partition should only be mounted
+ read-only. This is usually used for flash partitions
+ containing early-boot firmware images or data which should not
+ be clobbered.
- Example:
+ Example:
- flash@ff000000 {
- device_type = "rom";
- compatible = "direct-mapped";
- probe-type = "CFI";
- reg = <ff000000 01000000>;
- bank-width = <4>;
- partitions = <00000000 00f80000
- 00f80000 00080001>;
- partition-names = "fs\0firmware";
- };
+ flash@ff000000 {
+ compatible = "amd,am29lv128ml", "cfi-flash";
+ reg = <ff000000 01000000>;
+ bank-width = <4>;
+ device-width = <1>;
+ #address-cells = <1>;
+ #size-cells = <1>;
+ fs@0 {
+ label = "fs";
+ reg = <0 f80000>;
+ };
+ firmware@f80000 {
+ label ="firmware";
+ reg = <f80000 80000>;
+ read-only;
+ };
+ };
k) Global Utilities Block
fsl,has-rstcr;
};
+ l) Freescale Communications Processor Module
+
+ NOTE: This is an interim binding, and will likely change slightly,
+ as more devices are supported. The QE bindings especially are
+ incomplete.
+
+ i) Root CPM node
+
+ Properties:
+ - compatible : "fsl,cpm1", "fsl,cpm2", or "fsl,qe".
+ - reg : A 48-byte region beginning with CPCR.
+
+ Example:
+ cpm@119c0 {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ #interrupt-cells = <2>;
+ compatible = "fsl,mpc8272-cpm", "fsl,cpm2";
+ reg = <119c0 30>;
+ }
+
+ ii) Properties common to mulitple CPM/QE devices
+
+ - fsl,cpm-command : This value is ORed with the opcode and command flag
+ to specify the device on which a CPM command operates.
+
+ - fsl,cpm-brg : Indicates which baud rate generator the device
+ is associated with. If absent, an unused BRG
+ should be dynamically allocated. If zero, the
+ device uses an external clock rather than a BRG.
+
+ - reg : Unless otherwise specified, the first resource represents the
+ scc/fcc/ucc registers, and the second represents the device's
+ parameter RAM region (if it has one).
+
+ iii) Serial
+
+ Currently defined compatibles:
+ - fsl,cpm1-smc-uart
+ - fsl,cpm2-smc-uart
+ - fsl,cpm1-scc-uart
+ - fsl,cpm2-scc-uart
+ - fsl,qe-uart
+
+ Example:
+
+ serial@11a00 {
+ device_type = "serial";
+ compatible = "fsl,mpc8272-scc-uart",
+ "fsl,cpm2-scc-uart";
+ reg = <11a00 20 8000 100>;
+ interrupts = <28 8>;
+ interrupt-parent = <&PIC>;
+ fsl,cpm-brg = <1>;
+ fsl,cpm-command = <00800000>;
+ };
+
+ iii) Network
+
+ Currently defined compatibles:
+ - fsl,cpm1-scc-enet
+ - fsl,cpm2-scc-enet
+ - fsl,cpm1-fec-enet
+ - fsl,cpm2-fcc-enet (third resource is GFEMR)
+ - fsl,qe-enet
+
+ Example:
+
+ ethernet@11300 {
+ device_type = "network";
+ compatible = "fsl,mpc8272-fcc-enet",
+ "fsl,cpm2-fcc-enet";
+ reg = <11300 20 8400 100 11390 1>;
+ local-mac-address = [ 00 00 00 00 00 00 ];
+ interrupts = <20 8>;
+ interrupt-parent = <&PIC>;
+ phy-handle = <&PHY0>;
+ linux,network-index = <0>;
+ fsl,cpm-command = <12000300>;
+ };
+
+ iv) MDIO
+
+ Currently defined compatibles:
+ fsl,pq1-fec-mdio (reg is same as first resource of FEC device)
+ fsl,cpm2-mdio-bitbang (reg is port C registers)
+
+ Properties for fsl,cpm2-mdio-bitbang:
+ fsl,mdio-pin : pin of port C controlling mdio data
+ fsl,mdc-pin : pin of port C controlling mdio clock
+
+ Example:
+
+ mdio@10d40 {
+ device_type = "mdio";
+ compatible = "fsl,mpc8272ads-mdio-bitbang",
+ "fsl,mpc8272-mdio-bitbang",
+ "fsl,cpm2-mdio-bitbang";
+ reg = <10d40 14>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+ fsl,mdio-pin = <12>;
+ fsl,mdc-pin = <13>;
+ };
+
+ v) Baud Rate Generators
+
+ Currently defined compatibles:
+ fsl,cpm-brg
+ fsl,cpm1-brg
+ fsl,cpm2-brg
+
+ Properties:
+ - reg : There may be an arbitrary number of reg resources; BRG
+ numbers are assigned to these in order.
+ - clock-frequency : Specifies the base frequency driving
+ the BRG.
+
+ Example:
+
+ brg@119f0 {
+ compatible = "fsl,mpc8272-brg",
+ "fsl,cpm2-brg",
+ "fsl,cpm-brg";
+ reg = <119f0 10 115f0 10>;
+ clock-frequency = <d#25000000>;
+ };
+
+ vi) Interrupt Controllers
+
+ Currently defined compatibles:
+ - fsl,cpm1-pic
+ - only one interrupt cell
+ - fsl,pq1-pic
+ - fsl,cpm2-pic
+ - second interrupt cell is level/sense:
+ - 2 is falling edge
+ - 8 is active low
+
+ Example:
+
+ interrupt-controller@10c00 {
+ #interrupt-cells = <2>;
+ interrupt-controller;
+ reg = <10c00 80>;
+ compatible = "mpc8272-pic", "fsl,cpm2-pic";
+ };
+
+ vii) USB (Universal Serial Bus Controller)
+
+ Properties:
+ - compatible : "fsl,cpm1-usb", "fsl,cpm2-usb", "fsl,qe-usb"
+
+ Example:
+ usb@11bc0 {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ compatible = "fsl,cpm2-usb";
+ reg = <11b60 18 8b00 100>;
+ interrupts = <b 8>;
+ interrupt-parent = <&PIC>;
+ fsl,cpm-command = <2e600000>;
+ };
+
+ viii) Multi-User RAM (MURAM)
+
+ The multi-user/dual-ported RAM is expressed as a bus under the CPM node.
+
+ Ranges must be set up subject to the following restrictions:
+
+ - Children's reg nodes must be offsets from the start of all muram, even
+ if the user-data area does not begin at zero.
+ - If multiple range entries are used, the difference between the parent
+ address and the child address must be the same in all, so that a single
+ mapping can cover them all while maintaining the ability to determine
+ CPM-side offsets with pointer subtraction. It is recommended that
+ multiple range entries not be used.
+ - A child address of zero must be translatable, even if no reg resources
+ contain it.
+
+ A child "data" node must exist, compatible with "fsl,cpm-muram-data", to
+ indicate the portion of muram that is usable by the OS for arbitrary
+ purposes. The data node may have an arbitrary number of reg resources,
+ all of which contribute to the allocatable muram pool.
+
+ Example, based on mpc8272:
+
+ muram@0 {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <0 0 10000>;
+
+ data@0 {
+ compatible = "fsl,cpm-muram-data";
+ reg = <0 2000 9800 800>;
+ };
+ };
+
+ m) Chipselect/Local Bus
+
+ Properties:
+ - name : Should be localbus
+ - #address-cells : Should be either two or three. The first cell is the
+ chipselect number, and the remaining cells are the
+ offset into the chipselect.
+ - #size-cells : Either one or two, depending on how large each chipselect
+ can be.
+ - ranges : Each range corresponds to a single chipselect, and cover
+ the entire access window as configured.
+
+ Example:
+ localbus@f0010100 {
+ compatible = "fsl,mpc8272ads-localbus",
+ "fsl,mpc8272-localbus",
+ "fsl,pq2-localbus";
+ #address-cells = <2>;
+ #size-cells = <1>;
+ reg = <f0010100 40>;
+
+ ranges = <0 0 fe000000 02000000
+ 1 0 f4500000 00008000>;
+
+ flash@0,0 {
+ compatible = "jedec-flash";
+ reg = <0 0 2000000>;
+ bank-width = <4>;
+ device-width = <1>;
+ };
+
+ board-control@1,0 {
+ reg = <1 0 20>;
+ compatible = "fsl,mpc8272ads-bcsr";
+ };
+ };
+
- h) 4xx/Axon EMAC ethernet nodes
+ n) 4xx/Axon EMAC ethernet nodes
The EMAC ethernet controller in IBM and AMCC 4xx chips, and also
the Axon bridge. To operate this needs to interact with a ths
available.
For Axon: 0x0000012a
+ l) Xilinx IP cores
+
+ The Xilinx EDK toolchain ships with a set of IP cores (devices) for use
+ in Xilinx Spartan and Virtex FPGAs. The devices cover the whole range
+ of standard device types (network, serial, etc.) and miscellanious
+ devices (gpio, LCD, spi, etc). Also, since these devices are
+ implemented within the fpga fabric every instance of the device can be
+ synthesised with different options that change the behaviour.
+
+ Each IP-core has a set of parameters which the FPGA designer can use to
+ control how the core is synthesized. Historically, the EDK tool would
+ extract the device parameters relevant to device drivers and copy them
+ into an 'xparameters.h' in the form of #define symbols. This tells the
+ device drivers how the IP cores are configured, but it requres the kernel
+ to be recompiled every time the FPGA bitstream is resynthesized.
+
+ The new approach is to export the parameters into the device tree and
+ generate a new device tree each time the FPGA bitstream changes. The
+ parameters which used to be exported as #defines will now become
+ properties of the device node. In general, device nodes for IP-cores
+ will take the following form:
+
+ (name)@(base-address) {
+ compatible = "xlnx,(ip-core-name)-(HW_VER)"
+ [, (list of compatible devices), ...];
+ reg = <(baseaddr) (size)>;
+ interrupt-parent = <&interrupt-controller-phandle>;
+ interrupts = < ... >;
+ xlnx,(parameter1) = "(string-value)";
+ xlnx,(parameter2) = <(int-value)>;
+ };
+
+ (ip-core-name): the name of the ip block (given after the BEGIN
+ directive in system.mhs). Should be in lowercase
+ and all underscores '_' converted to dashes '-'.
+ (name): is derived from the "PARAMETER INSTANCE" value.
+ (parameter#): C_* parameters from system.mhs. The C_ prefix is
+ dropped from the parameter name, the name is converted
+ to lowercase and all underscore '_' characters are
+ converted to dashes '-'.
+ (baseaddr): the C_BASEADDR parameter.
+ (HW_VER): from the HW_VER parameter.
+ (size): equals C_HIGHADDR - C_BASEADDR + 1
+
+ Typically, the compatible list will include the exact IP core version
+ followed by an older IP core version which implements the same
+ interface or any other device with the same interface.
+
+ 'reg', 'interrupt-parent' and 'interrupts' are all optional properties.
+
+ For example, the following block from system.mhs:
+
+ BEGIN opb_uartlite
+ PARAMETER INSTANCE = opb_uartlite_0
+ PARAMETER HW_VER = 1.00.b
+ PARAMETER C_BAUDRATE = 115200
+ PARAMETER C_DATA_BITS = 8
+ PARAMETER C_ODD_PARITY = 0
+ PARAMETER C_USE_PARITY = 0
+ PARAMETER C_CLK_FREQ = 50000000
+ PARAMETER C_BASEADDR = 0xEC100000
+ PARAMETER C_HIGHADDR = 0xEC10FFFF
+ BUS_INTERFACE SOPB = opb_7
+ PORT OPB_Clk = CLK_50MHz
+ PORT Interrupt = opb_uartlite_0_Interrupt
+ PORT RX = opb_uartlite_0_RX
+ PORT TX = opb_uartlite_0_TX
+ PORT OPB_Rst = sys_bus_reset_0
+ END
+
+ becomes the following device tree node:
+
+ opb-uartlite-0@ec100000 {
+ device_type = "serial";
+ compatible = "xlnx,opb-uartlite-1.00.b";
+ reg = <ec100000 10000>;
+ interrupt-parent = <&opb-intc>;
+ interrupts = <1 0>; // got this from the opb_intc parameters
+ current-speed = <d#115200>; // standard serial device prop
+ clock-frequency = <d#50000000>; // standard serial device prop
+ xlnx,data-bits = <8>;
+ xlnx,odd-parity = <0>;
+ xlnx,use-parity = <0>;
+ };
+
+ Some IP cores actually implement 2 or more logical devices. In this case,
+ the device should still describe the whole IP core with a single node
+ and add a child node for each logical device. The ranges property can
+ be used to translate from parent IP-core to the registers of each device.
+ (Note: this makes the assumption that both logical devices have the same
+ bus binding. If this is not true, then separate nodes should be used for
+ each logical device). The 'cell-index' property can be used to enumerate
+ logical devices within an IP core. For example, the following is the
+ system.mhs entry for the dual ps2 controller found on the ml403 reference
+ design.
+
+ BEGIN opb_ps2_dual_ref
+ PARAMETER INSTANCE = opb_ps2_dual_ref_0
+ PARAMETER HW_VER = 1.00.a
+ PARAMETER C_BASEADDR = 0xA9000000
+ PARAMETER C_HIGHADDR = 0xA9001FFF
+ BUS_INTERFACE SOPB = opb_v20_0
+ PORT Sys_Intr1 = ps2_1_intr
+ PORT Sys_Intr2 = ps2_2_intr
+ PORT Clkin1 = ps2_clk_rx_1
+ PORT Clkin2 = ps2_clk_rx_2
+ PORT Clkpd1 = ps2_clk_tx_1
+ PORT Clkpd2 = ps2_clk_tx_2
+ PORT Rx1 = ps2_d_rx_1
+ PORT Rx2 = ps2_d_rx_2
+ PORT Txpd1 = ps2_d_tx_1
+ PORT Txpd2 = ps2_d_tx_2
+ END
+
+ It would result in the following device tree nodes:
+
+ opb_ps2_dual_ref_0@a9000000 {
+ ranges = <0 a9000000 2000>;
+ // If this device had extra parameters, then they would
+ // go here.
+ ps2@0 {
+ compatible = "xlnx,opb-ps2-dual-ref-1.00.a";
+ reg = <0 40>;
+ interrupt-parent = <&opb-intc>;
+ interrupts = <3 0>;
+ cell-index = <0>;
+ };
+ ps2@1000 {
+ compatible = "xlnx,opb-ps2-dual-ref-1.00.a";
+ reg = <1000 40>;
+ interrupt-parent = <&opb-intc>;
+ interrupts = <3 0>;
+ cell-index = <0>;
+ };
+ };
+
+ Also, the system.mhs file defines bus attachments from the processor
+ to the devices. The device tree structure should reflect the bus
+ attachments. Again an example; this system.mhs fragment:
+
+ BEGIN ppc405_virtex4
+ PARAMETER INSTANCE = ppc405_0
+ PARAMETER HW_VER = 1.01.a
+ BUS_INTERFACE DPLB = plb_v34_0
+ BUS_INTERFACE IPLB = plb_v34_0
+ END
+
+ BEGIN opb_intc
+ PARAMETER INSTANCE = opb_intc_0
+ PARAMETER HW_VER = 1.00.c
+ PARAMETER C_BASEADDR = 0xD1000FC0
+ PARAMETER C_HIGHADDR = 0xD1000FDF
+ BUS_INTERFACE SOPB = opb_v20_0
+ END
+
+ BEGIN opb_uart16550
+ PARAMETER INSTANCE = opb_uart16550_0
+ PARAMETER HW_VER = 1.00.d
+ PARAMETER C_BASEADDR = 0xa0000000
+ PARAMETER C_HIGHADDR = 0xa0001FFF
+ BUS_INTERFACE SOPB = opb_v20_0
+ END
+
+ BEGIN plb_v34
+ PARAMETER INSTANCE = plb_v34_0
+ PARAMETER HW_VER = 1.02.a
+ END
+
+ BEGIN plb_bram_if_cntlr
+ PARAMETER INSTANCE = plb_bram_if_cntlr_0
+ PARAMETER HW_VER = 1.00.b
+ PARAMETER C_BASEADDR = 0xFFFF0000
+ PARAMETER C_HIGHADDR = 0xFFFFFFFF
+ BUS_INTERFACE SPLB = plb_v34_0
+ END
+
+ BEGIN plb2opb_bridge
+ PARAMETER INSTANCE = plb2opb_bridge_0
+ PARAMETER HW_VER = 1.01.a
+ PARAMETER C_RNG0_BASEADDR = 0x20000000
+ PARAMETER C_RNG0_HIGHADDR = 0x3FFFFFFF
+ PARAMETER C_RNG1_BASEADDR = 0x60000000
+ PARAMETER C_RNG1_HIGHADDR = 0x7FFFFFFF
+ PARAMETER C_RNG2_BASEADDR = 0x80000000
+ PARAMETER C_RNG2_HIGHADDR = 0xBFFFFFFF
+ PARAMETER C_RNG3_BASEADDR = 0xC0000000
+ PARAMETER C_RNG3_HIGHADDR = 0xDFFFFFFF
+ BUS_INTERFACE SPLB = plb_v34_0
+ BUS_INTERFACE MOPB = opb_v20_0
+ END
+
+ Gives this device tree (some properties removed for clarity):
+
+ plb-v34-0 {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ device_type = "ibm,plb";
+ ranges; // 1:1 translation
+
+ plb-bram-if-cntrl-0@ffff0000 {
+ reg = <ffff0000 10000>;
+ }
+
+ opb-v20-0 {
+ #address-cells = <1>;
+ #size-cells = <1>;
+ ranges = <20000000 20000000 20000000
+ 60000000 60000000 20000000
+ 80000000 80000000 40000000
+ c0000000 c0000000 20000000>;
+
+ opb-uart16550-0@a0000000 {
+ reg = <a00000000 2000>;
+ };
+
+ opb-intc-0@d1000fc0 {
+ reg = <d1000fc0 20>;
+ };
+ };
+ };
+
+ That covers the general approach to binding xilinx IP cores into the
+ device tree. The following are bindings for specific devices:
+
+ i) Xilinx ML300 Framebuffer
+
+ Simple framebuffer device from the ML300 reference design (also on the
+ ML403 reference design as well as others).
+
+ Optional properties:
+ - resolution = <xres yres> : pixel resolution of framebuffer. Some
+ implementations use a different resolution.
+ Default is <d#640 d#480>
+ - virt-resolution = <xvirt yvirt> : Size of framebuffer in memory.
+ Default is <d#1024 d#480>.
+ - rotate-display (empty) : rotate display 180 degrees.
+
+ ii) Xilinx SystemACE
+
+ The Xilinx SystemACE device is used to program FPGAs from an FPGA
+ bitstream stored on a CF card. It can also be used as a generic CF
+ interface device.
+
+ Optional properties:
+ - 8-bit (empty) : Set this property for SystemACE in 8 bit mode
+
+ iii) Xilinx EMAC and Xilinx TEMAC
+
+ Xilinx Ethernet devices. In addition to general xilinx properties
+ listed above, nodes for these devices should include a phy-handle
+ property, and may include other common network device properties
+ like local-mac-address.
+
+ iv) Xilinx Uartlite
+
+ Xilinx uartlite devices are simple fixed speed serial ports.
+
+ Requred properties:
+ - current-speed : Baud rate of uartlite
+
More devices will be defined as this spec matures.
VII - Specifying interrupt information for devices