Table of Contents

Introduction

This page gives an overview of Xilinx Multi-Scaler driver, which is available as part of the Xilinx Linux distribution.

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• The driver is tested with YUY2, NV16, NV12, RGB, GRAY8, UYVY and BGR Gstreamer formats only.  
• Please check section below on Stride and Height align.

Kernel Configuration

The following config options should be enabled in order to build Xilinx Multi-Scaler driver

CONFIG_VIDEO_XILINX

CONFIG_VIDEO_DEV

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CONFIG_VIDEO_XILINX_MULTISCALER

To check if the options are enabled run the following:

petalinux-config -c kernel

When the GUI opens, you can use '/' to search for each config.

The driver is available at,
https://github.com/Xilinx/linux-xlnx/blob/master/drivers/media/platform/xilinx/xilinx-multi-scaler.c

Device Tree Binding

The device tree node will be automatically generated, if the core is configured in the HW design, using the Device Tree BSP.

Steps to generate device-tree is documented here,
http://www.wiki.xilinx.com/Build+Device+Tree+Blob

And a sample binding is shown below and the description of DT property is documented here

v_multi_scaler_1: v_multi_scaler@a0000000 {
          clock-names = "ap_clk";
          clocks = <&misc_clk_0>;
          compatible = "xlnx,v-multi-scaler-1.0", "xlnx,v-multi-scaler-v1.0";
          interrupt-names = "interrupt";
          interrupt-parent = <&gic>;
          interrupts = <0 89 4>;
          reg = <0x0 0xa0000000 0x0 0x20000>;
          reset-gpios = <&gpio 78 1>;
          xlnx,dma-addr-width = <0x20>;
          xlnx,max-chan = <8>;
          xlnx,max-height = <2160>;
          xlnx,max-width = <3840>;
          xlnx,num-taps = <12>;
          xlnx,pixels-per-clock = /bits/ 8 <2>;
          xlnx,vid-formats = "xrgb8888", "bgr888", "xbgr8888", "xbgr2101010", "uyvy", "y8", "y10", "vuy888", "xvuy8888", "yuvx2101010", "yuyv", "nv12", "nv16", "xv20", "xv15";
};                                

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1. Gstreamer plugins enumerate all the channel/video devices for each of gst command. So, there might be chances that starting all channels with different gst process at same time do not allow the actual process to open the device and the process dedicated for the device does not start. For example, if all channels are opened immediately in a script, all the gst process open and close all the devices for all the channels and if somehow gst process 1 opens channel 2 and at same time if process 2 open channel 2, the 2^nd process do not get the channel 2 and returns, despite the process 1 do not require the channel 2 and close the channel 2 afterwards.  Adding sleep after every enumeration is required to make all applications work properly.   

2. The gstreamer plugins mentioned on this page are developed for Proof of Concept and testing some limited featured only. This plugins are not tested for all possible resolutions, video formats etc. Customers may need to develop their own plugins by using these plugins as example.

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