Merge pull request #1156 from DoctorWkt/platform-rosco-r2

Kernel/platform/platform-rosco-r2: A port of FUZIX to the Rosco r2 m68k SBC.

Kernel/platform/platform-rosco-r2/Makefile

@@ -0,0 +1,70 @@
+
+CSRCS = devtty.c
+CSRCS += devices.c main.c libc.c
+CSRCS += devch375.c devch375_discard.c
+
+ASRCS = p68000.S crt0.S
+ASRCS += tricks.S
+
+DSRCS = ../../dev/mbr.c ../../dev/blkdev.c
+DSRCS += ../../dev/devsd.c ../../dev/devsd_discard.c
+DOBJS = $(patsubst ../../dev/%.c,%.o, $(DSRCS))
+
+LSRCS = ../../lib/68000exception.c ../../lib/68000usercopy.c
+LSRCS += ../../lib/68000relocate.c
+LOBJS = $(patsubst ../../lib/%.c,%.o, $(LSRCS))
+
+COBJS = $(CSRCS:.c=$(BINEXT))
+AOBJS = $(ASRCS:.S=.o)
+OBJS  = $(COBJS) $(AOBJS) $(DOBJS) $(LOBJS)
+
+CROSS_CCOPTS += -I../../dev/
+
+all:	$(OBJS)
+
+$(COBJS): %.o: %.c
+	$(CROSS_CC) $(CROSS_CCOPTS) -c $<
+
+$(AOBJS): %.o: %.S
+	$(CROSS_AS) $(ASOPTS) $< -o $*.o
+
+$(DOBJS): %.o: ../../dev/%.c
+	$(CROSS_CC) $(CROSS_CCOPTS) -c $<
+
+$(LOBJS): %.o: ../../lib/%.c
+	$(CROSS_CC) $(CROSS_CCOPTS) -c $<
+
+tricks.S: ../../lib/68000flat.S
+
+clean:
+	rm -f *.o fuzix.elf core *~ fuzix.dis
+
+image:
+	$(CROSS_LD) -M -o fuzix.elf -T fuzix.ld p68000.o ../../start.o \
+	  ../../version.o ../../cpu-68000/lowlevel-68000.o tricks.o \
+	  main.o ../../timer.o ../../kdata.o 68000exception.o \
+	  devices.o ../../devio.o ../../filesys.o ../../process.o \
+	  ../../inode.o ../../syscall_fs.o ../../syscall_proc.o \
+	  ../../syscall_other.o ../../mm.o ../../flat.o ../../blk512.o \
+	  ../../tty.o ../../devsys.o ../../usermem.o ../../syscall_fs2.o \
+	  ../../syscall_fs3.o ../../syscall_exec32.o ../../syscall_exec.o \
+	  blkdev.o mbr.o 68000relocate.o \
+	  devsd.o devsd_discard.o \
+	  devch375.o devch375_discard.o \
+	  68000usercopy.o ../../cpu-68000/usermem_std-68000.o devtty.o \
+	  libc.o ../../malloc.o ../../level2.o ../../syscall_level2.o \
+	  ../../select.o > ../../fuzix.map
+	$(CROSS_COMPILE)objcopy fuzix.elf -O binary ../../fuzix.bin
+	m68k-elf-objdump --disassemble -S fuzix.elf > fuzix.dis
+
+IMAGES = $(FUZIX_ROOT)/Images/$(TARGET)
+
+diskimage:
+	# Make a blank disk image with partition
+	dd if=$(FUZIX_ROOT)/Standalone/filesystem-src/parttab.40M of=$(IMAGES)/disk.img bs=40017920 conv=sync,swab
+	# Add the file system
+	dd if=$(IMAGES)/filesys.img of=$(IMAGES)/disk.img bs=512 seek=2048 conv=notrunc,swab
+	# Add the kernel
+	dd if=../../fuzix.bin of=$(IMAGES)/disk.img bs=512 seek=2 conv=notrunc,swab
+	# Make an emulator image of it
+	cat $(FUZIX_ROOT)/Standalone/filesystem-src/idehdr.40M $(IMAGES)/disk.img > $(IMAGES)/emu-ide.img

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

@@ -0,0 +1,151 @@
+# FUZIX Port to the Rosco r2 SBC
+
+Warren Toomey - 2025/02/05
+
+## Introduction
+
+This is the port of FUZIX to the Rosco r2 m68k SBC:
+https://github.com/rosco-m68k/rosco_m68k
+
+It's a work in progress and some things don't work well yet.
+
+## Building FUZIX
+
+You will need the toolchain described in
+https://github.com/rosco-m68k/rosco_m68k/blob/develop/code/Toolchain.md
+
+At the top-level FUZIX directory, you can do:
+
+```
+make TARGET=rosco-r2 kernel        # Build the kernel, which creates
+                                   # the file Kernel/fuzix.bin
+make TARGET=rosco-r2 diskimage     # Builds the libraries and applications,
+                                   # and then creates the filesystem image
+                                   # Images/rosco-r2/filesys.img
+make TARGET=rosco-r2 kclean        # Clean up the kernel build. Do this if
+                                   # you make any kernel config changes
+make TARGET=rosco-r2 clean         # Clean up everything
+```
+
+There is a shell script here called `mk_fs_img`. Once you have
+`Kernel/fuzix.bin` and `Images/rosco-r2/filesys.img` you can run
+this script to make the SD card image `sdcard.img` which has the
+bootable kernel in partition 1 and the populated FUZIX filesystem
+in partition 2.
+
+## Booting with an SD Card
+
+Copy the card image `sdcard.img` to your SD card. Under Linux I do:
+
+```
+cat sdcard.img > /dev/sdc; sync; sync
+```
+
+At boot time, the SD card should appear as `hda` with two partitions.
+Use the boot device `hda2` and login as `root` with no password:
+
+```
+FUZIX version 0.5
+Copyright (c) 1988-2002 by H.F.Bower, D.Braun, S.Nitschke, H.Peraza
+Copyright (c) 1997-2001 by Arcady Schekochikhin, Adriano C. R. da Cunha
+Copyright (c) 2013-2015 Will Sowerbutts <[email protected]>
+Copyright (c) 2014-2025 Alan Cox <[email protected]>
+Devboot
+Motorola 68010 processor detected.
+1024KiB total RAM, 917KiB available to processes (125 processes max)
+Enabling interrupts ... ok.
+SD drive 0: hda: hda1 hda2 
+CH375 device: not found
+bootdev: hda2
+...
+login: root
+```
+
+## Booting with the CH375 Device and a USB Drive
+
+If you have built the CH375 daughter board as described
+[here](https://github.com/DoctorWkt/xv6-rosco-r2/tree/ch375/hardware)
+then you can copy the FUZIX filesystem to a USB drive and mount it
+as the root device.
+
+However, as the Rosco r2 SBC boots from the SD card, you need to copy
+the SD card image `sdcard.img` to both your SD card and your USB drive.
+
+At boot time, the SD card should appear as `hdb` with two partitions.
+Use the boot device `hdb2` and login as `root` with no password.
+
+If you have installed 1M of expansion RAM on the daughter board and closed
+jumper JP4, then the kernel will see the extra RAM and report that you have
+2M of RAM.
+
+```
+FUZIX version 0.5
+Copyright (c) 1988-2002 by H.F.Bower, D.Braun, S.Nitschke, H.Peraza
+Copyright (c) 1997-2001 by Arcady Schekochikhin, Adriano C. R. da Cunha
+Copyright (c) 2013-2015 Will Sowerbutts <[email protected]>
+Copyright (c) 2014-2025 Alan Cox <[email protected]>
+Devboot
+Motorola 68010 processor detected.
+2048KiB total RAM, 1941KiB available to processes (125 processes max)
+Enabling interrupts ... ok.
+SD drive 0: hda: hda1 hda2 
+CH375 device: hdb: hdb1 hdb2 
+bootdev: hdb2
+...
+login: root
+```
+
+## Configuration
+
+Look in `config.h` for compile-time configuration defines.
+`TTY_INIT_BAUD` is set for 115200 baud. `CONFIG_FLAT` means we have no MMU.
+`CONFIG_SD` and `SD_DRIVE_COUNT` sets us up for one SD card.
+`CONFIG_USB` supports my USB expansion board:
+https://github.com/DoctorWkt/xv6-rosco-r2/tree/ch375/hardware
+
+This line in `fuzix.ld`:
+
+```
+ram (rwx) : ORIGIN = 0x2000, LENGTH = 0x100000-0x2000
+```
+
+says that the kernel starts at $2000 and we have $100000 (1 Meg) of RAM.
+
+## Booting
+
+The Rosco ROM loads the kernel at address $40000. The code in `crt0.S`
+copies the kernel down to $2000. Then, interrupts are enabled and the
+BSS gets cleared. These functions are then called: `init_early()`,
+`init_hardware()` and `fuzix_main()`.
+
+## Devices
+
+`devices.c` holds a tables of devices and associated functions. The
+main ones are the block devices (0) and the tty device (2). 
+`device_init()` is called to probe devices and initialise them.
+
+## The DUART
+
+The code to use the XR68C681 DUART is in `devtty.c`. I have made the
+`tty_setup()` function do essentially nothing. The Rosco ROM sets the
+DUART up for 115200 baud. The Fuzix code then does something which
+scrambles the 115200 baud setting. Until I can figure it out, I've
+just disabled it.
+
+## The SD Card
+
+The kernel is configured to have SD card support. The file `p68000.S` has
+assembly functions to bit-bang the SD card using the DUART:
+
+```
+                .globl sd_spi_clock
+                .globl sd_spi_raise_cs
+                .globl sd_spi_lower_cs
+                .globl sd_spi_transmit_byte
+                .globl sd_spi_receive_byte
+                .globl sd_spi_transmit_sector
+                .globl sd_spi_receive_sector
+```
+
+and the high-level SD card code is in `Kernel/dev/devsd.c` and
+`Kernel/dev/devsd_discard.c`.

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

@@ -0,0 +1,63 @@
+/* Enable to make ^Z dump the inode table for debug */
+#undef CONFIG_IDUMP
+/* Enable to make ^A drop back into the monitor */
+#undef CONFIG_MONITOR
+/* Profil syscall support (not yet complete) */
+#undef CONFIG_PROFIL
+
+#define CONFIG_32BIT
+#define CONFIG_LEVEL_2
+
+#define CONFIG_MULTI
+#define CONFIG_FLAT
+#define CONFIG_SPLIT_ID
+#define CONFIG_PARENT_FIRST
+/* It's not that meaningful but we currently chunk to 512 bytes */
+#define CONFIG_BANKS 	(65536/512)
+
+#define CONFIG_LARGE_IO_DIRECT(x)	1
+
+#define CONFIG_SPLIT_UDATA
+#define UDATA_SIZE	1024
+#define UDATA_BLKS	2
+
+#define TICKSPERSEC 100   /* Ticks per second */
+
+#define BOOT_TTY (512 + 1)   /* Set this to default device for stdio, stderr */
+                          /* In this case, the default is the first TTY device */
+                            /* Temp FIXME set to serial port for debug ease */
+
+/* We need a tidier way to do this from the loader */
+#define CMDLINE	NULL	  /* Location of root dev name */
+
+/* Device parameters */
+#define NUM_DEV_TTY 2
+#define TTYDEV   BOOT_TTY /* Device used by kernel for messages, panics */
+
+/* Could be bigger but we need to add hashing first and it's not clearly
+   a win with a CF card anyway */
+#define NBUFS    16       /* Number of block buffers */
+#define NMOUNTS	 8	  /* Number of mounts at a time */
+
+#define MAX_BLKDEV 2
+
+/* Block dvices */
+#define CONFIG_IDE
+#define CONFIG_SD
+#define SD_DRIVE_COUNT  1
+#define CONFIG_CH375
+
+#define plt_copyright()
+
+/* Note: select() in the level 2 code will not work on this configuration
+   at the moment as select is limited to 16 processes. FIXME - support a
+   hash ELKS style for bigger systems where wakeup aliasing is cheaper */
+
+#define PTABSIZE	125
+#define UFTSIZE		16
+#define OFTSIZE		160
+#define ITABSIZE	176
+
+#define BOOTDEVICENAMES "hd#"
+
+#define TTY_INIT_BAUD	B115200

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

@@ -0,0 +1,51 @@
+/*
+ *	Need to wipe BSS etc once we figure out our preferred boot method
+ *
+ *	On entry we are loaded at $40000. We copy ourselves down to $400.
+ *	We are in supervisor mode and the rest is our problem.
+ */
+		#include "../../cpu-68000/kernel-68000.def"
+
+		.globl start
+		.globl start2
+		.globl __end
+		.globl __bss_start
+
+.mri 1
+
+start:
+		/* Position-independent code to copy from start to
+		 * __bss_start down to $400. Code borrowed from the
+		 * Rosco loader code.
+		 */
+RELOC:                           /* position-independent load addr */
+    lea.l   RELOC(PC),A0         /* PC-rel source addr (load addr) */
+    move.l  #start,A1            /* absolute dest addr (run addr) */
+    move.l  #__bss_start,D0      /* init section absolute end addr */
+    sub.l   A1,D0                /* subtract dest addr for init length */
+    lsr.l   #2,D0                /* convert to long words */
+    subq.l  #1,D0                /* subtract 1 for dbra */
+.INIT_LOOP:
+    move.l  (A0)+,(A1)+          /* copy long word from source to dest */
+    dbra    D0,.INIT_LOOP        /* loop until __bss_start */
+
+    move.l  #start2,A0		 /* Use A0, otherwise the generated code */
+				 /* is PC-relative which we don't want. */
+    jmp	    (A0)	 	 /* Jump to the copied start2 code */
+
+start2:
+		or #$0700,sr
+		move.l #__bss_start,a0
+		move.l #__end,d0
+		sub.l a0,d0
+		lsr.l #2,d0
+wipebss:
+		clr.l (a0)+
+		dbra d0,wipebss
+
+		lea udata_block0+UBLOCK_SIZE,a7
+		bsr init_early
+		bsr init_hardware
+		bsr fuzix_main
+		or #$0700,sr
+stop:		bra stop

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

@@ -0,0 +1,41 @@
+/*-----------------------------------------------------------------------*/
+/* Fuzix CH375 USB block device driver                                   */
+/* 2025 Warren Toomey                                                    */
+/*                                                                       */
+/* This one is different from the one in Kernel/dev as it assumes that   */
+/* the CH375 device will send interrupts.                                */
+/*-----------------------------------------------------------------------*/
+
+#include <kernel.h>
+#include <kdata.h>
+#include <printf.h>
+#include <timer.h>
+#include <stdbool.h>
+#include <blkdev.h>
+#include <devch375.h>
+
+#ifdef CONFIG_CH375
+
+extern uint32_t ch375_read_block(uint8_t *buf, uint32_t lba);
+extern uint32_t ch375_write_block(uint8_t *buf, uint32_t lba);
+
+uint_fast8_t devch375_transfer_sector(void)
+{
+    bool success;
+    uint32_t lba= blk_op.lba;
+
+    /* Disable interrupts while we do the transfer */
+    /* but keep IRQ5 enabled as we use it */
+    irqflags_t irq = di();
+    irqrestore(4);	/* IRQ4 is ignored, 5 is OK */
+
+    if (blk_op.is_read) {
+	success= ch375_read_block(blk_op.addr, lba);
+    } else {
+	success= ch375_write_block(blk_op.addr, lba);
+    }
+    irqrestore(irq);
+    return(success);
+}
+
+#endif