This version (18 Mar 2021 18:07) was approved by Michael Hennerich.The Previously approved version (18 Mar 2021 18:04) is available.
Table of Contents
ADI JESD204B/C AXI_ADXCVR Highspeed Transceivers Linux Driver
Supported Devices
Description
The JESD204B/C AXI_ADXCVR Highspeed Transceivers peripheral driver is a simple driver that supports the AXI_ADXCVR Physical Layer Highspeed Transceivers HDL Core. The driver reads some configuration from the devicetree and configures the peripheral accordingly. After configuration has completed the JESD204 link is enabled, this driver also supports PHY layer PRBS generation and checking, or 2D statistical EyeScan.
This driver also work in conjunction with the JESD204 (FSM) Interface Linux Kernel Framework, in this case JESD204B/C link configuration is provided by the JESD204-FSM framework.
Source Code
Status
| Source | Mainlined? |
|---|---|
| drivers/iio/jesd204/axi_adxcvr.c | No |
Files Xilinx
| Function | File |
|---|---|
| driver | drivers/iio/jesd204/axi_adxcvr.c |
| driver | drivers/iio/jesd204/axi_adxcvr_eyescan.c |
| driver | drivers/iio/jesd204/xilinx_transceiver.c |
| incude | drivers/iio/jesd204/axi_adxcvr.h |
| incude | drivers/iio/jesd204/axi_adxcvr_eyescan.h |
| incude | drivers/iio/jesd204/xilinx_transceiver.h |
| dt-bindings | include/dt-bindings/jesd204/adxcvr.h |
Files Intel / Altera
| Function | File |
|---|---|
| driver | drivers/iio/jesd204/altera_adxcvr.c |
| driver | drivers/iio/jesd204/altera_a10_atx_pll.c |
| driver | drivers/iio/jesd204/altera_a10_cdr_pll.c |
Example platform device initialization
The AXI JESD204B driver is a platform driver and can currently only be instantiated via device tree.
Deprecated Non-jesd204-fsm mode
Required devicetree properties:
- compatible: Must always be “adi,axi-adxcvr-1.00”
- reg: Base address and register area size. This parameter expects a register range
- clock-names: List of input clock names - “s_axi_aclk”, “conv”, “div40”
- clocks: Clock phandles and specifiers (See clock bindings for details on clock-names and clocks)
- clock-output-names: Generated clocks
- adi,sys-clk-select: 2 bit variable. For ultrascale, it selects the PLL reference clock source to be forwarded to the OUTCLK MUX: 0-CPLL, 3-QPLL0. Check RX/TXSYSCLKSEL parameter in the transceiver documentation for the FPGA you're using. See Table
- adi,out-clk-select: 3 bit variable. Controls the OUTCLKSEL multiplexer, controlling what will be forwarded to OUTCLK pin. Check RX/TXOUTCLKSEL parameter in the transceiver documentation for the FPGA you're using See Table
Optional devicetree properties:
- adi,use-lpm-enable: If set, the transceiver will be used in LPM mode. Otherwise, will be used in DFE mode. See transceiver documentation for details
- adi,use-cpll-enable: If set, the CPLL will be used for these transceivers
Optional devicetree clock-names:
- conv2: Optional SERDES (CPLL/QPLL) REFCLK from a difference source which rate and state must be in sync with the main conv clk.
Example:
#include <dt-bindings/jesd204/adxcvr.h> axi_adrv9009_adxcvr_rx: axi-adxcvr-rx@84a40000 { #address-cells = <1>; #size-cells = <0>; compatible = "adi,axi-adxcvr-1.0"; reg = <0x0 0x84a40000 0x1000>; clocks = <&hmc7044 5>, <&hmc7044 7>; clock-names = "conv", "div40"; #clock-cells = <1>; clock-output-names = "rx_gt_clk", "rx_out_clk"; adi,sys-clk-select = <XCVR_CPLL>; adi,out-clk-select = <XCVR_REFCLK>; adi,use-lpm-enable; }; axi_adrv9009_adxcvr_tx: axi-adxcvr-tx@84a20000 { #address-cells = <1>; #size-cells = <0>; compatible = "adi,axi-adxcvr-1.0"; reg = <0x0 0x84a20000 0x1000>; clocks = <&hmc7044 4>, <&hmc7044 6>; clock-names = "conv", "div40"; #clock-cells = <1>; clock-output-names = "tx_gt_clk", "tx_out_clk"; adi,sys-clk-select = <XCVR_QPLL>; adi,out-clk-select = <XCVR_REFCLK>; };
jesd204-fsm mode
When using the JESD204 (FSM) Interface Linux Kernel Framework the div40 or Link/Device clock is handled by the Link Layer Peripheral Linux device driver.
Required devicetree properties:
- compatible: Must always be “adi,axi-adxcvr-1.00”
- reg: Base address and register area size. This parameter expects a register range
- clock-names: List of input clock names - “s_axi_aclk”, “conv”
- clocks: Clock phandles and specifiers (See clock bindings for details on clock-names and clocks)
- clock-output-names: Generated clocks
- adi,sys-clk-select: 2 bit variable. For ultrascale, it selects the PLL reference clock source to be forwarded to the OUTCLK MUX: 0-CPLL, 3-QPLL0. Check RX/TXSYSCLKSEL parameter in the transceiver documentation for the FPGA you're using. See Table
- adi,out-clk-select: 3 bit variable. Controls the OUTCLKSEL multiplexer, controlling what will be forwarded to OUTCLK pin. Check RX/TXOUTCLKSEL parameter in the transceiver documentation for the FPGA you're using. See Table
- jesd204-device: Adds device to the jesd204-fsm kernel framework
- jesd204-inputs: jesd204-fsm devices phandles and specifiers (used to build the link topology)
Optional devicetree properties:
- adi,use-lpm-enable: If set, the transceiver will be used in LPM mode. Otherwise, will be used in DFE mode. See transceiver documentation for details
Example:
#include <dt-bindings/jesd204/adxcvr.h> axi_adrv9009_adxcvr_rx: axi-adxcvr-rx@84a40000 { #address-cells = <1>; #size-cells = <0>; compatible = "adi,axi-adxcvr-1.0"; reg = <0x0 0x84a40000 0x1000>; clocks = <&hmc7044 5>; clock-names = "conv"; #clock-cells = <1>; clock-output-names = "rx_gt_clk", "rx_out_clk"; adi,sys-clk-select = <XCVR_CPLL>; adi,out-clk-select = <XCVR_REFCLK>; adi,use-lpm-enable; jesd204-device; #jesd204-cells = <2>; jesd204-inputs = <&hmc7044 0 FRAMER_LINK_RX>; }; axi_adrv9009_adxcvr_tx: axi-adxcvr-tx@84a20000 { #address-cells = <1>; #size-cells = <0>; compatible = "adi,axi-adxcvr-1.0"; reg = <0x0 0x84a20000 0x1000>; clocks = <&hmc7044 4>; clock-names = "conv"; #clock-cells = <1>; clock-output-names = "tx_gt_clk", "tx_out_clk"; adi,sys-clk-select = <XCVR_QPLL>; adi,out-clk-select = <XCVR_REFCLK>; jesd204-device; #jesd204-cells = <2>; jesd204-inputs = <&hmc7044 0 DEFRAMER_LINK_TX>; };
Enabling Linux driver support
Configure kernel with “make menuconfig” (alternatively use “make xconfig” or “make qconfig”)
Linux Kernel Configuration
Device Drivers --->
<*> Industrial I/O support --->
--- Industrial I/O support
-*- Enable ring buffer support within IIO
-*- Industrial I/O lock free software ring
-*- Enable triggered sampling support
<*> JESD204 High-Speed Serial Interface Support --->
[--snip--]
<*> Analog Devices AXI ADXCVR PHY Support
[--snip--]
Sysfs Interface
This driver provides advanced diagnostics, status and control via sysfs. Depending on the direction (RX vs. TX) the provided sysfs attributes vary. A brief summary is with examples are provided below.
Low level register access via reg_access
This device driver features an optional debug facility, allowing users to read or write registers directly. Special care needs to be taken when using this feature, since you can modify registers on the back of the driver.
The DEBUG register access sysfs attribute reg_access allows access to the the AXI HDL Core register space as well as to the Dynamic Reconfiguration Port (DRP) interfaces. Accessing this sysfs attribute requires root privileges.
AXI register access
Format:
axi <REGISTER ADDRESS> [<WRITE VAL>]
Example reading AXI register at offset 0 (REG_VERSION)
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# echo axi 0x0 > reg_access root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# cat reg_access 0x110261
Example writing AXI register at offset 8 (REG_SCRATCH)
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# echo axi 0x8 0x1234 > reg_access root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# cat reg_access 0x1234
DRP register access
Please see Transceiver User Guides for further details
Format:
drp <DRP PORT> <REGISTER ADDRESS> [<WRITE VAL>]
| DRP Port | Comment |
|---|---|
| 0 | Common register space |
| 0x100 + Lane | Channel register space |
Example reading OUT_DIV:
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# echo drp 0x101 0x88 > reg_access root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# cat reg_access 0x2AA
axi-adxcvr-rx
This specifies any shell prompt running on the target
root@analog:~# cd /sys/bus/platform/devices/84a60000.axi-adxcvr-rx root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# ls -al total 0 drwxr-xr-x 4 root root 0 Feb 6 13:41 . drwxr-xr-x 12 root root 0 Feb 6 13:41 .. lrwxrwxrwx 1 root root 0 Feb 6 13:41 driver -> ../../../../bus/platform/drivers/axi_adxcvr -rw-r--r-- 1 root root 4096 Feb 6 13:42 driver_override -rw-r--r-- 1 root root 4096 Feb 6 13:42 enable -r--r--r-- 1 root root 2091000 Feb 6 13:42 eye_data -r--r--r-- 1 root root 4096 Feb 6 13:42 eyescan_info drwxr-xr-x 3 root root 0 Feb 6 13:41 jesd204:6 -r--r--r-- 1 root root 4096 Feb 6 13:42 modalias lrwxrwxrwx 1 root root 0 Feb 6 13:42 of_node -> ../../../../firmware/devicetree/base/fpga-axi@0/axi-adxcvr-rx@84a60000 drwxr-xr-x 2 root root 0 Feb 6 13:42 power --w------- 1 root root 4096 Feb 6 13:42 prbs_counter_reset -rw-r--r-- 1 root root 4096 Feb 6 13:42 prbs_error_counters -rw-r--r-- 1 root root 4096 Feb 6 13:42 prbs_select -r--r--r-- 1 root root 4096 Feb 6 13:42 prbs_status -rw-r--r-- 1 root root 4096 Feb 6 13:42 prescale -rw-r--r-- 1 root root 4096 Feb 6 13:42 reg_access lrwxrwxrwx 1 root root 0 Feb 6 13:41 subsystem -> ../../../../bus/platform -rw-r--r-- 1 root root 4096 Feb 6 13:41 uevent
prbs_select
Writing prbs_select selects the PRBS type. (accepted values depend on the GT architecture).
Reading returns the selected type.
| Value | Comment |
|---|---|
| 0 | PRBS_DISABLE |
| 7 | PRBS7 |
| 9 | PRBS9 |
| 15 | PRBS15 |
| 23 | PRBS23 |
| 31 | PRBS31 |
Example:
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# echo 23 > prbs_select root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# cat prbs_select 23 root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx#
prbs_status
Reading returns a status string. Values are:
| Value | Comment |
|---|---|
| unlocked | The PRBS is unlocked |
| valid | he PRBS is locked and no errors are detected |
| error | The PRBS has locked but errors were detected |
These conditions are sticky and can be cleared by writing 1 to
prbs_counter_reset
Example:
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# cat prbs_status valid
prbs_error_counters
Reading returns a string with error counts for each physical JESD204 lane.
Example:
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# cat prbs_error_counters 0 0 0 0 0 0 0 0
prbs_counter_reset
Writing 1 will clear the prbs_status and reset the prbs_error_counters
Example:
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# echo 1 > prbs_counter_reset
JESD204 Eye Scan
Please see here: JESD204 Eye Scan
Following commands visualize how to control the eyescan from the command line.
eyescan_info provides the necessary information to reconstruct the eye from the binary bitmap retrieved from eye_data. Such as the resolution format, lane rate, number of lanes, CDR data width, LMP mode, etc. Using the prescale attribute the iteration time at each offset can be controlled, so increasing prescale will also increase the time a eye capture needs to complete. Writing enable with the physical lane number, will start the capture processes. While the capture is in progress reading eye_data will block. If this is not desired the user can poll enable, which will return -EBUSY while a capture is in progress. Once the capture finished the lane number of the last captured lane is returned.
Reading the eyescan_info:
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# cat eyescan_info x65,y255 CDRDW: 40 LPM: 1 NL: 8 LR: 15000000
Configure the prescale:
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# echo 1 > prescale root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# cat prescale 1
Enable the eye capture:
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# echo 1 > enable root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# cat enable cat: enable: Device or resource busy
Retrieve the binary bitmap: (needs post processing)
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# cat enable 1 root@analog:/sys/bus/platform/devices/84a60000.axi-adxcvr-rx# hexdump eye_data 0000000 ffff 00a7 ffff 00a7 ffff 00a8 ffff 00a7 0000010 ffff 00a7 ffff 00a9 ffff 00aa ffff 00ac 0000020 ffff 00b1 ffff 00bb ffff 00c7 ffff 00d6 0000030 ffff 00ed ffff 010b ffff 012c ffff 015e 0000040 ffff 019a ffff 01f6 ffff 0287 ffff 0373 0000050 ffff 0544 ffff 08ce ffff 11ce ffff 27d6 0000060 ffff 75b9 a10c ffff 23c3 ffff 05b4 ffff [-- snip --]
axi-adxcvr-tx
This specifies any shell prompt running on the target
root@analog:~# cd /sys/bus/platform/devices/84b60000.axi-adxcvr-tx root@analog:/sys/bus/platform/devices/84b60000.axi-adxcvr-tx# ls -l total 0 lrwxrwxrwx 1 root root 0 Feb 6 13:41 driver -> ../../../../bus/platform/drivers/axi_adxcvr -rw-r--r-- 1 root root 4096 Feb 6 14:32 driver_override drwxr-xr-x 3 root root 0 Feb 6 13:41 jesd204:7 -r--r--r-- 1 root root 4096 Feb 6 14:32 modalias lrwxrwxrwx 1 root root 0 Feb 6 14:32 of_node -> ../../../../firmware/devicetree/base/fpga-axi@0/axi-adxcvr-tx@84b60000 drwxr-xr-x 2 root root 0 Feb 6 14:32 power --w------- 1 root root 4096 Feb 6 14:32 prbs_error_inject -rw-r--r-- 1 root root 4096 Feb 6 14:32 prbs_select -rw-r--r-- 1 root root 4096 Feb 6 14:32 reg_access lrwxrwxrwx 1 root root 0 Feb 6 13:41 subsystem -> ../../../../bus/platform -rw-r--r-- 1 root root 4096 Feb 6 13:41 uevent
prbs_select
Writing prbs_select selects the PRBS type. (accepted values depend on the GT architecture).
Reading returns the selected type.
| Value | Comment |
|---|---|
| 0 | PRBS_DISABLE |
| 7 | PRBS7 |
| 9 | PRBS9 |
| 15 | PRBS15 |
| 23 | PRBS23 |
| 31 | PRBS31 |
Example:
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84b60000.axi-adxcvr-tx# echo 15 > prbs_select root@analog:/sys/bus/platform/devices/84b60000.axi-adxcvr-tx# cat prbs_select 15 root@analog:/sys/bus/platform/devices/84b60000.axi-adxcvr-tx#
prbs_error_inject
Writing 1 injects a series of errors´(used for testing)
Example:
This specifies any shell prompt running on the target
root@analog:/sys/bus/platform/devices/84b60000.axi-adxcvr-tx# echo 1 > prbs_error_inject root@analog:/sys/bus/platform/devices/84b60000.axi-adxcvr-tx#
More Information
resources/tools-software/linux-drivers/jesd204/axi_adxcvr.txt · Last modified: 18 Mar 2021 18:06 by Michael Hennerich