add riscv_core Repository

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "riscv_core/SparrowRV"]
+	path = riscv_core/SparrowRV
+	url = https://gitee.com/xiaowuzxc/SparrowRV

README.md

@@ -1,5 +1,13 @@
 # TangNano-20K-example
 
+---
+- IDE 基础使用步骤:[点我](https://wiki.sipeed.com/hardware/zh/tang/tang-nano-20k/example/led.html)
+- IDE Instructions:[Click me](https://wiki.sipeed.com/hardware/en/tang/tang-nano-20k/example/led.html)
+---
+- 配置 MS5351:[点我](https://wiki.sipeed.com/hardware/zh/tang/tang-nano-20k/example/unbox.html)
+- Config MS5351:[Click me](https://wiki.sipeed.com/hardware/en/tang/tang-nano-20k/example/unbox.html)
+---
+
 - [TangNano-20K-example](#tangnano-20k-example)
   - [audio](#audio)
   - [hdmi](#hdmi)
@@ -8,6 +16,9 @@
   - [uart](#uart)
   - [ws2812](#ws2812)
   - [nestang](#nestang)
+  - [linux](#linux)
+  - [riscv\_core](#riscv_core)
+    - [SparrowRV](#sparrowrv)
 
 
 ## audio
@@ -43,3 +54,13 @@ A demo to drive onboard ws2812 rgb led.
 ## nestang
 
 Thanks to [nand2mario](https://github.com/nand2mario) for providing this project, and read [guide](./nestang/README.md) to see how to build this project.
+
+## linux
+
+A linux demo based on [Linux-on-LiteX-VexRiscv](https://github.com/litex-hub/linux-on-litex-vexriscv).
+
+## riscv_core
+
+### SparrowRV
+
+A Risc-V architecture open source core. Run `git submodule --init update` to get the code.

linux/image/boot.json

@@ -0,0 +1,5 @@
+{
+	"Image":			"0x40000000",
+	"sipeed_tang_nano_20k.dtb":	"0x40780000",
+	"opensbi.bin.tangnano20k":	"0x407c0000"
+}

linux/image/sipeed_tang_nano_20k.dts

@@ -0,0 +1,129 @@
+
+/dts-v1/;
+
+/ {
+        #address-cells = <1>;
+        #size-cells    = <1>;
+
+
+        chosen {
+            bootargs = "console=liteuart earlycon=liteuart,0xf0001000";
+        };
+
+        cpus {
+            #address-cells = <1>;
+            #size-cells    = <0>;
+            timebase-frequency = <48000000>;
+
+            CPU0: cpu@0 {
+                device_type = "cpu";
+                compatible = "riscv";
+                riscv,isa = "rv32i2p0_ma";
+                mmu-type = "riscv,sv32";
+                reg = <0>;
+                clock-frequency = <48000000>;
+                status = "okay";
+                
+                d-cache-size = <4096>;
+                d-cache-sets = <1>;
+                d-cache-block-size = <64>;
+
+                i-cache-size = <4096>;
+                i-cache-sets = <1>;
+                i-cache-block-size = <64>;
+
+                
+                d-tlb-size = <4>;
+                d-tlb-sets = <4>;
+
+                i-tlb-size = <4>;
+                i-tlb-sets = <4>;
+
+                L0: interrupt-controller {
+                    #interrupt-cells = <0x00000001>;
+                    interrupt-controller;
+                    compatible = "riscv,cpu-intc";
+                };
+            };
+
+            
+        };
+
+        memory@40000000 {
+            device_type = "memory";
+            reg = <0x40000000 0x800000>;
+        };
+
+        reserved-memory {
+            #address-cells = <1>;
+            #size-cells    = <1>;
+            ranges;
+
+            opensbi@407c0000 {
+                reg = <0x407c0000 0x20000>;
+            };
+
+        };
+
+        clocks {
+            sys_clk: litex_sys_clk {
+                #clock-cells = <0>;
+                compatible = "fixed-clock";
+                clock-frequency = <48000000>;
+            };
+        };
+
+        soc {
+            #address-cells = <1>;
+            #size-cells    = <1>;
+            compatible = "simple-bus";
+            interrupt-parent = <&intc0>;
+            ranges;
+
+            soc_ctrl0: soc_controller@f0000800 {
+                compatible = "litex,soc-controller";
+                reg = <0xf0000800 0xc>;
+                status = "okay";
+            };
+
+            intc0: interrupt-controller@f0c00000 {
+                compatible = "sifive,fu540-c000-plic", "sifive,plic-1.0.0";
+                reg = <0xf0c00000 0x400000>;
+                #address-cells = <0>;
+                #interrupt-cells = <1>;
+                interrupt-controller;
+                interrupts-extended = <
+                    &L0 11 &L0 9>;
+                riscv,ndev = <32>;
+            };
+
+            liteuart0: serial@f0001000 {
+                compatible = "litex,liteuart";
+                reg = <0xf0001000 0x100>;
+                interrupts = <1>;
+                status = "okay";
+            };
+
+            leds: gpio@f0002800 {
+                compatible = "litex,gpio";
+                reg = <0xf0002800 0x4>;
+                gpio-controller;
+                #gpio-cells = <2>;
+                litex,direction = "out";
+                status = "disabled";
+            };
+
+        };
+
+        aliases {
+
+                serial0 = &liteuart0;
+
+        };
+
+};
+
+&leds {
+        litex,ngpio = <4>;
+        status = "okay";
+};

linux/readme.md

@@ -0,0 +1,20 @@
+# Tang Nano 20K Linux
+
+This `readme` tells how to run linux on Tang Nano 20k.
+
+## Environment
+
+OS: Linux
+Software: `Python`, `litex` [Click me to know litex](https://github.com/enjoy-digital/litex/wiki).
+
+## Instruction
+
+### Burn FPGA firmware
+
+`openFPGALoader -f -c ft2232 ./firmware/sipeed_tang_nano_20k.fs`
+
+### Load Linux image
+
+This will take a long tims.
+
+`litex_term --speed 3000000 --serial-boot --images ./image/boot.json /dev/ttyUSB1`

riscv_core/SparrowRV

@@ -0,0 +1 @@
+Subproject commit 3ecb22b91147a8d6d2e7c8700f67cb926a15fa12