1 d) Xilinx IP cores
2
3 The Xilinx EDK toolchain ships with a set of IP cores (devices) for use
4 in Xilinx Spartan and Virtex FPGAs. The devices cover the whole range
5 of standard device types (network, serial, etc.) and miscellaneous
6 devices (gpio, LCD, spi, etc). Also, since these devices are
7 implemented within the fpga fabric every instance of the device can be
8 synthesised with different options that change the behaviour.
9
10 Each IP-core has a set of parameters which the FPGA designer can use to
11 control how the core is synthesized. Historically, the EDK tool would
12 extract the device parameters relevant to device drivers and copy them
13 into an 'xparameters.h' in the form of #define symbols. This tells the
14 device drivers how the IP cores are configured, but it requires the kernel
15 to be recompiled every time the FPGA bitstream is resynthesized.
16
17 The new approach is to export the parameters into the device tree and
18 generate a new device tree each time the FPGA bitstream changes. The
19 parameters which used to be exported as #defines will now become
20 properties of the device node. In general, device nodes for IP-cores
21 will take the following form:
22
23 (name): (generic-name)@(base-address) {
24 compatible = "xlnx,(ip-core-name)-(HW_VER)"
25 [, (list of compatible devices), ...];
26 reg = <(baseaddr) (size)>;
27 interrupt-parent = <&interrupt-controller-phandle>;
28 interrupts = < ... >;
29 xlnx,(parameter1) = "(string-value)";
30 xlnx,(parameter2) = <(int-value)>;
31 };
32
33 (generic-name): an open firmware-style name that describes the
34 generic class of device. Preferably, this is one word, such
35 as 'serial' or 'ethernet'.
36 (ip-core-name): the name of the ip block (given after the BEGIN
37 directive in system.mhs). Should be in lowercase
38 and all underscores '_' converted to dashes '-'.
39 (name): is derived from the "PARAMETER INSTANCE" value.
40 (parameter#): C_* parameters from system.mhs. The C_ prefix is
41 dropped from the parameter name, the name is converted
42 to lowercase and all underscore '_' characters are
43 converted to dashes '-'.
44 (baseaddr): the baseaddr parameter value (often named C_BASEADDR).
45 (HW_VER): from the HW_VER parameter.
46 (size): the address range size (often C_HIGHADDR - C_BASEADDR + 1).
47
48 Typically, the compatible list will include the exact IP core version
49 followed by an older IP core version which implements the same
50 interface or any other device with the same interface.
51
52 'reg' and 'interrupts' are all optional properties.
53
54 For example, the following block from system.mhs:
55
56 BEGIN opb_uartlite
57 PARAMETER INSTANCE = opb_uartlite_0
58 PARAMETER HW_VER = 1.00.b
59 PARAMETER C_BAUDRATE = 115200
60 PARAMETER C_DATA_BITS = 8
61 PARAMETER C_ODD_PARITY = 0
62 PARAMETER C_USE_PARITY = 0
63 PARAMETER C_CLK_FREQ = 50000000
64 PARAMETER C_BASEADDR = 0xEC100000
65 PARAMETER C_HIGHADDR = 0xEC10FFFF
66 BUS_INTERFACE SOPB = opb_7
67 PORT OPB_Clk = CLK_50MHz
68 PORT Interrupt = opb_uartlite_0_Interrupt
69 PORT RX = opb_uartlite_0_RX
70 PORT TX = opb_uartlite_0_TX
71 PORT OPB_Rst = sys_bus_reset_0
72 END
73
74 becomes the following device tree node:
75
76 opb_uartlite_0: serial@ec100000 {
77 device_type = "serial";
78 compatible = "xlnx,opb-uartlite-1.00.b";
79 reg = <ec100000 10000>;
80 interrupt-parent = <&opb_intc_0>;
81 interrupts = <1 0>; // got this from the opb_intc parameters
82 current-speed = <d#115200>; // standard serial device prop
83 clock-frequency = <d#50000000>; // standard serial device prop
84 xlnx,data-bits = <8>;
85 xlnx,odd-parity = <0>;
86 xlnx,use-parity = <0>;
87 };
88
89 That covers the general approach to binding xilinx IP cores into the
90 device tree. The following are bindings for specific devices:
91
92 i) Xilinx ML300 Framebuffer
93
94 Simple framebuffer device from the ML300 reference design (also on the
95 ML403 reference design as well as others).
96
97 Optional properties:
98 - resolution = <xres yres> : pixel resolution of framebuffer. Some
99 implementations use a different resolution.
100 Default is <d#640 d#480>
101 - virt-resolution = <xvirt yvirt> : Size of framebuffer in memory.
102 Default is <d#1024 d#480>.
103 - rotate-display (empty) : rotate display 180 degrees.
104
105 ii) Xilinx SystemACE
106
107 The Xilinx SystemACE device is used to program FPGAs from an FPGA
108 bitstream stored on a CF card. It can also be used as a generic CF
109 interface device.
110
111 Optional properties:
112 - 8-bit (empty) : Set this property for SystemACE in 8 bit mode
113
114 iii) Xilinx EMAC and Xilinx TEMAC
115
116 Xilinx Ethernet devices. In addition to general xilinx properties
117 listed above, nodes for these devices should include a phy-handle
118 property, and may include other common network device properties
119 like local-mac-address.
120
121 iv) Xilinx Uartlite
122
123 Xilinx uartlite devices are simple fixed speed serial ports.
124
125 Required properties:
126 - current-speed : Baud rate of uartlite
127
128 v) Xilinx hwicap
129
130 Xilinx hwicap devices provide access to the configuration logic
131 of the FPGA through the Internal Configuration Access Port
132 (ICAP). The ICAP enables partial reconfiguration of the FPGA,
133 readback of the configuration information, and some control over
134 'warm boots' of the FPGA fabric.
135
136 Required properties:
137 - xlnx,family : The family of the FPGA, necessary since the
138 capabilities of the underlying ICAP hardware
139 differ between different families. May be
140 'virtex2p', 'virtex4', or 'virtex5'.
141 - compatible : should contain "xlnx,xps-hwicap-1.00.a" or
142 "xlnx,opb-hwicap-1.00.b".
143
144 vi) Xilinx Uart 16550
145
146 Xilinx UART 16550 devices are very similar to the NS16550 but with
147 different register spacing and an offset from the base address.
148
149 Required properties:
150 - clock-frequency : Frequency of the clock input
151 - reg-offset : A value of 3 is required
152 - reg-shift : A value of 2 is required
153
154 vii) Xilinx USB Host controller
155
156 The Xilinx USB host controller is EHCI compatible but with a different
157 base address for the EHCI registers, and it is always a big-endian
158 USB Host controller. The hardware can be configured as high speed only,
159 or high speed/full speed hybrid.
160
161 Required properties:
162 - xlnx,support-usb-fs: A value 0 means the core is built as high speed
163 only. A value 1 means the core also supports
164 full speed devices.
165
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