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Merge pull request #1156 from DoctorWkt/platform-rosco-r2
Kernel/platform/platform-rosco-r2: A port of FUZIX to the Rosco r2 m68k SBC.
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‎Kernel/platform/platform-rosco-r2/Makefile

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CSRCS = devtty.c
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CSRCS += devices.c main.c libc.c
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CSRCS += devch375.c devch375_discard.c
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ASRCS = p68000.S crt0.S
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ASRCS += tricks.S
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DSRCS = ../../dev/mbr.c ../../dev/blkdev.c
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DSRCS += ../../dev/devsd.c ../../dev/devsd_discard.c
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DOBJS = $(patsubst ../../dev/%.c,%.o, $(DSRCS))
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LSRCS = ../../lib/68000exception.c ../../lib/68000usercopy.c
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LSRCS += ../../lib/68000relocate.c
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LOBJS = $(patsubst ../../lib/%.c,%.o, $(LSRCS))
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COBJS = $(CSRCS:.c=$(BINEXT))
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AOBJS = $(ASRCS:.S=.o)
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OBJS = $(COBJS) $(AOBJS) $(DOBJS) $(LOBJS)
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CROSS_CCOPTS += -I../../dev/
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all: $(OBJS)
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$(COBJS): %.o: %.c
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$(CROSS_CC) $(CROSS_CCOPTS) -c $<
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$(AOBJS): %.o: %.S
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$(CROSS_AS) $(ASOPTS) $< -o $*.o
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$(DOBJS): %.o: ../../dev/%.c
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$(CROSS_CC) $(CROSS_CCOPTS) -c $<
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$(LOBJS): %.o: ../../lib/%.c
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$(CROSS_CC) $(CROSS_CCOPTS) -c $<
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tricks.S: ../../lib/68000flat.S
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clean:
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rm -f *.o fuzix.elf core *~ fuzix.dis
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image:
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$(CROSS_LD) -M -o fuzix.elf -T fuzix.ld p68000.o ../../start.o \
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../../version.o ../../cpu-68000/lowlevel-68000.o tricks.o \
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main.o ../../timer.o ../../kdata.o 68000exception.o \
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devices.o ../../devio.o ../../filesys.o ../../process.o \
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../../inode.o ../../syscall_fs.o ../../syscall_proc.o \
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../../syscall_other.o ../../mm.o ../../flat.o ../../blk512.o \
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../../tty.o ../../devsys.o ../../usermem.o ../../syscall_fs2.o \
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../../syscall_fs3.o ../../syscall_exec32.o ../../syscall_exec.o \
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blkdev.o mbr.o 68000relocate.o \
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devsd.o devsd_discard.o \
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devch375.o devch375_discard.o \
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68000usercopy.o ../../cpu-68000/usermem_std-68000.o devtty.o \
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libc.o ../../malloc.o ../../level2.o ../../syscall_level2.o \
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../../select.o > ../../fuzix.map
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$(CROSS_COMPILE)objcopy fuzix.elf -O binary ../../fuzix.bin
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m68k-elf-objdump --disassemble -S fuzix.elf > fuzix.dis
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IMAGES = $(FUZIX_ROOT)/Images/$(TARGET)
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diskimage:
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# Make a blank disk image with partition
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dd if=$(FUZIX_ROOT)/Standalone/filesystem-src/parttab.40M of=$(IMAGES)/disk.img bs=40017920 conv=sync,swab
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# Add the file system
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dd if=$(IMAGES)/filesys.img of=$(IMAGES)/disk.img bs=512 seek=2048 conv=notrunc,swab
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# Add the kernel
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dd if=../../fuzix.bin of=$(IMAGES)/disk.img bs=512 seek=2 conv=notrunc,swab
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# Make an emulator image of it
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cat $(FUZIX_ROOT)/Standalone/filesystem-src/idehdr.40M $(IMAGES)/disk.img > $(IMAGES)/emu-ide.img

‎Kernel/platform/platform-rosco-r2/README.md

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# FUZIX Port to the Rosco r2 SBC
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Warren Toomey - 2025/02/05
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## Introduction
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This is the port of FUZIX to the Rosco r2 m68k SBC:
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https://github.com/rosco-m68k/rosco_m68k
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It's a work in progress and some things don't work well yet.
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## Building FUZIX
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You will need the toolchain described in
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https://github.com/rosco-m68k/rosco_m68k/blob/develop/code/Toolchain.md
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At the top-level FUZIX directory, you can do:
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```
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make TARGET=rosco-r2 kernel # Build the kernel, which creates
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# the file Kernel/fuzix.bin
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make TARGET=rosco-r2 diskimage # Builds the libraries and applications,
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# and then creates the filesystem image
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# Images/rosco-r2/filesys.img
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make TARGET=rosco-r2 kclean # Clean up the kernel build. Do this if
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# you make any kernel config changes
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make TARGET=rosco-r2 clean # Clean up everything
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```
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There is a shell script here called `mk_fs_img`. Once you have
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`Kernel/fuzix.bin` and `Images/rosco-r2/filesys.img` you can run
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this script to make the SD card image `sdcard.img` which has the
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bootable kernel in partition 1 and the populated FUZIX filesystem
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in partition 2.
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## Booting with an SD Card
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Copy the card image `sdcard.img` to your SD card. Under Linux I do:
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```
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cat sdcard.img > /dev/sdc; sync; sync
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```
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At boot time, the SD card should appear as `hda` with two partitions.
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Use the boot device `hda2` and login as `root` with no password:
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```
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FUZIX version 0.5
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Copyright (c) 1988-2002 by H.F.Bower, D.Braun, S.Nitschke, H.Peraza
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Copyright (c) 1997-2001 by Arcady Schekochikhin, Adriano C. R. da Cunha
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Copyright (c) 2013-2015 Will Sowerbutts <will@sowerbutts.com>
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Copyright (c) 2014-2025 Alan Cox <alan@etchedpixels.co.uk>
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Devboot
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Motorola 68010 processor detected.
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1024KiB total RAM, 917KiB available to processes (125 processes max)
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Enabling interrupts ... ok.
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SD drive 0: hda: hda1 hda2
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CH375 device: not found
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bootdev: hda2
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...
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login: root
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```
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## Booting with the CH375 Device and a USB Drive
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If you have built the CH375 daughter board as described
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[here](https://github.com/DoctorWkt/xv6-rosco-r2/tree/ch375/hardware)
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then you can copy the FUZIX filesystem to a USB drive and mount it
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as the root device.
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However, as the Rosco r2 SBC boots from the SD card, you need to copy
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the SD card image `sdcard.img` to both your SD card and your USB drive.
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At boot time, the SD card should appear as `hdb` with two partitions.
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Use the boot device `hdb2` and login as `root` with no password.
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If you have installed 1M of expansion RAM on the daughter board and closed
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jumper JP4, then the kernel will see the extra RAM and report that you have
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2M of RAM.
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```
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FUZIX version 0.5
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Copyright (c) 1988-2002 by H.F.Bower, D.Braun, S.Nitschke, H.Peraza
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Copyright (c) 1997-2001 by Arcady Schekochikhin, Adriano C. R. da Cunha
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Copyright (c) 2013-2015 Will Sowerbutts <will@sowerbutts.com>
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Copyright (c) 2014-2025 Alan Cox <alan@etchedpixels.co.uk>
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Devboot
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Motorola 68010 processor detected.
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2048KiB total RAM, 1941KiB available to processes (125 processes max)
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Enabling interrupts ... ok.
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SD drive 0: hda: hda1 hda2
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CH375 device: hdb: hdb1 hdb2
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bootdev: hdb2
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...
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login: root
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```
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## Configuration
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Look in `config.h` for compile-time configuration defines.
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`TTY_INIT_BAUD` is set for 115200 baud. `CONFIG_FLAT` means we have no MMU.
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`CONFIG_SD` and `SD_DRIVE_COUNT` sets us up for one SD card.
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`CONFIG_USB` supports my USB expansion board:
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https://github.com/DoctorWkt/xv6-rosco-r2/tree/ch375/hardware
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This line in `fuzix.ld`:
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```
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ram (rwx) : ORIGIN = 0x2000, LENGTH = 0x100000-0x2000
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```
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says that the kernel starts at $2000 and we have $100000 (1 Meg) of RAM.
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## Booting
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The Rosco ROM loads the kernel at address $40000. The code in `crt0.S`
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copies the kernel down to $2000. Then, interrupts are enabled and the
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BSS gets cleared. These functions are then called: `init_early()`,
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`init_hardware()` and `fuzix_main()`.
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## Devices
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`devices.c` holds a tables of devices and associated functions. The
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main ones are the block devices (0) and the tty device (2).
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`device_init()` is called to probe devices and initialise them.
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## The DUART
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The code to use the XR68C681 DUART is in `devtty.c`. I have made the
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`tty_setup()` function do essentially nothing. The Rosco ROM sets the
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DUART up for 115200 baud. The Fuzix code then does something which
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scrambles the 115200 baud setting. Until I can figure it out, I've
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just disabled it.
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## The SD Card
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The kernel is configured to have SD card support. The file `p68000.S` has
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assembly functions to bit-bang the SD card using the DUART:
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```
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.globl sd_spi_clock
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.globl sd_spi_raise_cs
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.globl sd_spi_lower_cs
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.globl sd_spi_transmit_byte
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.globl sd_spi_receive_byte
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.globl sd_spi_transmit_sector
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.globl sd_spi_receive_sector
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```
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and the high-level SD card code is in `Kernel/dev/devsd.c` and
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`Kernel/dev/devsd_discard.c`.

‎Kernel/platform/platform-rosco-r2/config.h

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/* Enable to make ^Z dump the inode table for debug */
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#undef CONFIG_IDUMP
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/* Enable to make ^A drop back into the monitor */
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#undef CONFIG_MONITOR
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/* Profil syscall support (not yet complete) */
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#undef CONFIG_PROFIL
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#define CONFIG_32BIT
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#define CONFIG_LEVEL_2
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#define CONFIG_MULTI
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#define CONFIG_FLAT
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#define CONFIG_SPLIT_ID
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#define CONFIG_PARENT_FIRST
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/* It's not that meaningful but we currently chunk to 512 bytes */
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#define CONFIG_BANKS (65536/512)
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#define CONFIG_LARGE_IO_DIRECT(x) 1
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#define CONFIG_SPLIT_UDATA
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#define UDATA_SIZE 1024
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#define UDATA_BLKS 2
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#define TICKSPERSEC 100 /* Ticks per second */
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#define BOOT_TTY (512 + 1) /* Set this to default device for stdio, stderr */
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/* In this case, the default is the first TTY device */
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/* Temp FIXME set to serial port for debug ease */
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/* We need a tidier way to do this from the loader */
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#define CMDLINE NULL /* Location of root dev name */
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/* Device parameters */
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#define NUM_DEV_TTY 2
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#define TTYDEV BOOT_TTY /* Device used by kernel for messages, panics */
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/* Could be bigger but we need to add hashing first and it's not clearly
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a win with a CF card anyway */
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#define NBUFS 16 /* Number of block buffers */
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#define NMOUNTS 8 /* Number of mounts at a time */
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#define MAX_BLKDEV 2
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/* Block dvices */
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#define CONFIG_IDE
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#define CONFIG_SD
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#define SD_DRIVE_COUNT 1
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#define CONFIG_CH375
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#define plt_copyright()
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/* Note: select() in the level 2 code will not work on this configuration
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at the moment as select is limited to 16 processes. FIXME - support a
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hash ELKS style for bigger systems where wakeup aliasing is cheaper */
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#define PTABSIZE 125
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#define UFTSIZE 16
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#define OFTSIZE 160
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#define ITABSIZE 176
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#define BOOTDEVICENAMES "hd#"
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#define TTY_INIT_BAUD B115200

‎Kernel/platform/platform-rosco-r2/crt0.S

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/*
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* Need to wipe BSS etc once we figure out our preferred boot method
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*
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* On entry we are loaded at $40000. We copy ourselves down to $400.
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* We are in supervisor mode and the rest is our problem.
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*/
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#include "../../cpu-68000/kernel-68000.def"
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.globl start
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.globl start2
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.globl __end
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.globl __bss_start
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.mri 1
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start:
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/* Position-independent code to copy from start to
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* __bss_start down to $400. Code borrowed from the
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* Rosco loader code.
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*/
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RELOC: /* position-independent load addr */
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lea.l RELOC(PC),A0 /* PC-rel source addr (load addr) */
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move.l #start,A1 /* absolute dest addr (run addr) */
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move.l #__bss_start,D0 /* init section absolute end addr */
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sub.l A1,D0 /* subtract dest addr for init length */
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lsr.l #2,D0 /* convert to long words */
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subq.l #1,D0 /* subtract 1 for dbra */
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.INIT_LOOP:
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move.l (A0)+,(A1)+ /* copy long word from source to dest */
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dbra D0,.INIT_LOOP /* loop until __bss_start */
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move.l #start2,A0 /* Use A0, otherwise the generated code */
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/* is PC-relative which we don't want. */
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jmp (A0) /* Jump to the copied start2 code */
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start2:
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or #$0700,sr
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move.l #__bss_start,a0
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move.l #__end,d0
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sub.l a0,d0
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lsr.l #2,d0
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wipebss:
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clr.l (a0)+
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dbra d0,wipebss
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lea udata_block0+UBLOCK_SIZE,a7
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bsr init_early
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bsr init_hardware
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bsr fuzix_main
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or #$0700,sr
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stop: bra stop

‎Kernel/platform/platform-rosco-r2/devch375.c

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/*-----------------------------------------------------------------------*/
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/* Fuzix CH375 USB block device driver */
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/* 2025 Warren Toomey */
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/* */
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/* This one is different from the one in Kernel/dev as it assumes that */
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/* the CH375 device will send interrupts. */
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/*-----------------------------------------------------------------------*/
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#include <kernel.h>
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#include <kdata.h>
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#include <printf.h>
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#include <timer.h>
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#include <stdbool.h>
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#include <blkdev.h>
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#include <devch375.h>
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#ifdef CONFIG_CH375
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extern uint32_t ch375_read_block(uint8_t *buf, uint32_t lba);
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extern uint32_t ch375_write_block(uint8_t *buf, uint32_t lba);
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uint_fast8_t devch375_transfer_sector(void)
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{
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bool success;
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uint32_t lba= blk_op.lba;
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/* Disable interrupts while we do the transfer */
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/* but keep IRQ5 enabled as we use it */
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irqflags_t irq = di();
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irqrestore(4); /* IRQ4 is ignored, 5 is OK */
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if (blk_op.is_read) {
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success= ch375_read_block(blk_op.addr, lba);
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} else {
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success= ch375_write_block(blk_op.addr, lba);
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}
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irqrestore(irq);
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return(success);
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}
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#endif

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