Running Linux on Altera MAX10 FPGA board

This short document contains some information about running Linux on MIPSfpga-plus system that is deployed on Terasic DE10-Lite development board with Altera MAX10 chip and SDRAM. It is based on the MIPSfpga-SOC package documents.

Prerequisites

Terasic DE10-Lite development board (Altera MAX10 FPGA chip + SDRAM 64MB);
Bus blaster or MPSSE EJTAG debugger is connected and configured (for onboard debug)
Quartus Prime 16.1 for FPGA configuration synthesis;
Ubuntu 17.04 (x64) virtual machine for Linux and RAM-disk build with Codescape MIPS MTI GNU Linux toolchain installed and available from $PATH.
Ubuntu packages: openocd build-essential git libncurses5-dev bc unzip

MIPSfpga-plus RTL settings

those lines should be uncommented in mfp_ahb_lite_matrix_config.vh:
```
`define MFP_USE_SDRAM_MEMORY
`define MFP_USE_DUPLEX_UART
```
if you are using MPSSE debugger board (not BusBlaster) then
```
`define MFP_USE_MPSSE_DEBUGGER
```
you have to build the MIPSfpga-plus SoC and program the FPGA device.

Kernel and RAM-disk build

In program/10_linux directory.

get Linux and Buildroot source

git clone git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git kernel
git clone git://git.buildroot.net/buildroot

buildroot configure and build (using 2017.05.1 tag = commit f3d8beeb3694)

cd buildroot
git checkout 2017.05.1
git apply ../patches/MIPSfpga_buildroot.patch
make xilfpga_static_defconfig
make

Linux configure (using v4.12.1 tag = commit cb6621858813)

cd ../kernel/
ls -l ../buildroot/output/images/rootfs.cpio
git checkout v4.12.1
git apply ../patches/MIPSfpga_linux.patch
make ARCH=mips xilfpga_de10lite_defconfig
make ARCH=mips menuconfig

RAM-disk support enable:

General setup / [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
                Initramfs source file(s)
                    ../buildroot/output/images/rootfs.cpio
                [*] Support initial ramdisks compressed using gzip
Save -> Exit

Linux kernel build

make ARCH=mips CROSS_COMPILE=mips-mti-linux-gnu-

Device programming and kernel run

to see the system log you have to connect to the UART port
```
minicom --device /dev/ttyUSB1
```
to exit minicom use CTRL+A, then X
turn off the hardware flow control in minicom settings:

press CTRL+A, then O -> Serial port setup -> F Hardware flow control
upload and run kernel. You can upload the kernel that was build by yourself
```
./01_upload_compiled_image.sh
```
or use the already prepared kernel image from '10_linux/image' directory
```
./00_upload_presaved_image.sh
```

after the shord delay (because of EARLY_PRINTK disabled) the log like this will be shown:

Linux version 4.12.1+ (stas@ubuntu) (gcc version 4.9.2 (Codescape GNU Tools 2016.05-06 for MIPS MTI Linux) ) #1 Sat Jul 22 14:35:05 MSK 2017
CPU0 revision is: 00019e60 (MIPS M14KEc)
MIPS: machine is terasic,de10lite
Determined physical RAM map:
memory: 04000000 @ 00000000 (usable)
Initrd not found or empty - disabling initrd
Primary instruction cache 4kB, VIPT, 2-way, linesize 16 bytes.
Primary data cache 4kB, 2-way, VIPT, no aliases, linesize 16 bytes
Zone ranges:
  Normal   [mem 0x0000000000000000-0x0000000003ffffff]
Movable zone start for each node
Early memory node ranges
  node   0: [mem 0x0000000000000000-0x0000000003ffffff]
Initmem setup node 0 [mem 0x0000000000000000-0x0000000003ffffff]
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 16256
Kernel command line: console=ttyS0,115200
PID hash table entries: 256 (order: -2, 1024 bytes)
Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)
Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)
Memory: 60512K/65536K available (1830K kernel code, 99K rwdata, 320K rodata, 944K init, 185K bss, 5024K reserved, 0K cma-reserved)
NR_IRQS:8
clocksource: MIPS: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 38225208935 ns
sched_clock: 32 bits at 50MHz, resolution 20ns, wraps every 42949672950ns
Console: colour dummy device 80x25
Calibrating delay loop... 10.81 BogoMIPS (lpj=21632)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
devtmpfs: initialized
clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
futex hash table entries: 256 (order: -1, 3072 bytes)
clocksource: Switched to clocksource MIPS
random: fast init done
workingset: timestamp_bits=30 max_order=14 bucket_order=0
Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
console [ttyS0] disabled
b0400000.serial: ttyS0 at MMIO 0xb0401000 (irq = 0, base_baud = 3125000) is a 16550A
console [ttyS0] enabled
Freeing unused kernel memory: 944K
This architecture does not have kernel memory protection.
mount: mounting devpts on /dev/pts failed: No such device
mount: mounting tmpfs on /dev/shm failed: Invalid argument
mount: mounting tmpfs on /tmp failed: Invalid argument
mount: mounting tmpfs on /run failed: Invalid argument
Starting logging: OK
Initializing random number generator... done.
Starting network: ip: socket: Function not implemented
ip: socket: Function not implemented
FAIL

Welcome to MIPSfpga
mipsfpga login:

GPIO test

enter the system as 'root'

GPIO init and value set

ls /sys/class/gpio/
  export       gpiochip480  unexport
mount -t debugfs none /sys/kernel/debug
cat /sys/kernel/debug/gpio
  gpiochip0: GPIOs 480-511, parent: platform/bf800000.gpio, bf800000.gpio:
echo 480 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio480/direction
echo 1 > /sys/class/gpio/gpio480/value

after those actions LED0 should be ON