Updating Software Components - 2021.1 English

Adding XRT to the Root Filesystem

Vitis acceleration application uses XRT to control hardware. XRT provides a unified programming interface across Alveo™ Data Center accelerator cards to embedded use cases.

You must add the XRT kernel driver (zocl) and the user space library (xrt-dev) to rootfs and sysroot. Package xrt-dev enables you to compile Vitis applications that use the XRT API.

Updating the Device Tree for ZOCL

The zocl driver interface requires a device tree node to enable the interrupt connection.

The following is an example of the zocl device node.

&amba {
	zyxclmm_drm {
		compatible = "xlnx,zocl";
		status = "okay";
		interrupt-parent = <&axi_intc_0>;
		interrupts = <0  4>, <1  4>, <2  4>, <3  4>,
			     <4  4>, <5  4>, <6  4>, <7  4>,
			     <8  4>, <9  4>, <10 4>, <11 4>,
			     <12 4>, <13 4>, <14 4>, <15 4>,
			     <16 4>, <17 4>, <18 4>, <19 4>,
			     <20 4>, <21 4>, <22 4>, <23 4>,
			     <24 4>, <25 4>, <26 4>, <27 4>,
			     <28 4>, <29 4>, <30 4>, <31 4>;
	};
};

For more information, refer to the XRT documentation: https://xilinx.github.io/XRT/master/html/yocto.html.

Update Interrupt Controller Input Number

In the block diagram, the interrupt controller has not been connected to acceleration kernels. The auto-generated device tree reflects the hardware design of the block diagram and does not consider that v++ linker would connect the interrupt signals of kernels to interrupt controller. To enable these interrupts, override the interrupt input number of the interrupt controllers.

The following is an example on how to override AXI Interconnect node parameters in the system-user.dtsi.

&axi_intc_0 {
	xlnx,kind-of-intr = <0x0>;
	xlnx,num-intr-inputs = <0x20>;
	interrupt-parent = <&gic>;
	interrupts = <0 89 4>;
};

Declaring the Platform with /etc/xocl.txt

Platform name can be written into /etc/xocl.txt in the embedded platform rootfs, so that XRT knows which platform it is. Host application can use XRT API to get the platform name and check the comparability with xclbin and host application with platform.

Adjusting the CMA Size

XRT uses CMA for buffer object allocation. You must reserve sufficient memory for CMA in bootargs or the device tree to prevent running out of memory during acceleration application runtime.