minim8: A mini11 derived 68HC11 machine

Kernel/platform/platform-minim8/Makefile

@@ -0,0 +1,83 @@
+
+CSRCS = devtty.c
+CSRCS += devices.c main.c
+
+ASRCS = m8.S crt0.S sci.S
+ASRCS += tricks.S commonmem.S
+
+CDSRCS = discard.c
+
+DSRCS = ../../dev/tinydisk.c ../../dev/tinysd.c
+DNSRCS = ../../dev/net/net_w5x00.c
+DISCARD_DSRCS = ../../dev/tinydisk_discard.c ../../dev/tinysd_discard.c
+
+COBJS = $(CSRCS:.c=$(BINEXT))
+CDOBJS = $(CDSRCS:.c=$(BINEXT))
+AOBJS = $(ASRCS:.S=$(BINEXT))
+A68OBJS = $(patsubst ../../dev/68hc11/%.S,%.o, $(A68SRCS))
+DOBJS = $(patsubst ../../dev/%.c,%.o, $(DSRCS))
+DNOBJS = $(patsubst ../../dev/net/%.c,%.o, $(DNSRCS))
+DAOBJS = $(DASRCS:.S=$(BINEXT))
+DISCARD_DOBJS = $(patsubst ../../dev/%.c,%.o, $(DISCARD_DSRCS))
+
+OBJS  = $(COBJS) $(CDOBJS) $(AOBJS) $(A68OBJS) $(DOBJS) $(DAOBJS) $(DISCARD_DOBJS) $(DNOBJS)
+
+CROSS_CCOPTS += -I../../dev/ -I../../dev/68hc11/ -I../../dev/net/
+
+all:	$(OBJS)
+
+$(COBJS): %$(BINEXT): %.c
+	$(CROSS_CC) $(CROSS_CCOPTS) $(CROSS_CC_SEG1) $<
+
+$(CDOBJS): %$(BINEXT): %.c
+	$(CROSS_CC) $(CROSS_CCOPTS) $(CROSS_CC_SEGDISC) $<
+
+$(AOBJS): %$(BINEXT): %.S
+	cpp -E $<  >$*.s
+	$(CROSS_AS) $(ASOPTS) $*.s -o $*.o
+
+$(DOBJS): %$(BINEXT): ../../dev/%.c
+	$(CROSS_CC) $(CROSS_CCOPTS) $(CROSS_CC_SEG1) -c $<
+
+$(DNOBJS): %$(BINEXT): ../../dev/net/%.c
+	$(CROSS_CC) $(CROSS_CCOPTS) $(CROSS_CC_SEG1) -c $<
+
+$(DAOBJS): %$(BINEXT): ../../dev/%.S
+	$(CROSS_CC) $(CROSS_CCOPTS) $(CROSS_CC_SEG1) -c $<
+
+$(DISCARD_DOBJS): %$(BINEXT): ../../dev/%.c
+	$(CROSS_CC) $(CROSS_CCOPTS) $(CROSS_CC_SEGDISC) -c $<
+
+clean:
+	rm -f $(DOBJS) $(DAOBJS) $(OBJS) *.o *.s core *~ fuzix.bin fuzix.tmpmap
+	rm -f loadsd.elf loadsd
+
+image: loadsd
+	$(CROSS_LD) -M -T memory.x -relax -o ../../fuzix.elf crt0.o commonmem.o \
+	m8.o ../../start.o ../../version.o ../../cpu-68hc11/lowlevel-68hc11-flat.o \
+	tricks.o main.o discard.o ../../timer.o ../../kdata.o devices.o \
+	tinydisk.o tinydisk_discard.o tinysd.o tinysd_discard.o \
+	sci.o ../../syscall_net.o ../../network.o net_w5x00.o \
+	../../devio.o ../../filesys.o ../../process.o ../../inode.o ../../syscall_fs.o \
+	../../syscall_proc.o ../../syscall_other.o ../../mm.o ../../swap.o ../../bankfixed.o \
+	../../tty.o ../../devsys.o ../../syscall_fs2.o ../../syscall_fs3.o \
+	../../syscall_exec.o ../../syscall_exec16.o ../../blk512.o ../../memalloc_none.o \
+	../../usermem.o ../../cpu-68hc11/usermem_std-68hc11-flat.o devtty.o >../../fuzix.map
+	$(CROSS_OBJCOPY) ../../fuzix.elf -O binary ../../fuzix.bin
+
+loadsd: loadsd.S loadsd.x
+	$(CROSS_CC) -c loadsd.S
+	$(CROSS_LD) -M -T loadsd.x -relax -o loadsd.elf loadsd.o >loadsd.map
+	$(CROSS_OBJCOPY) loadsd.elf -O binary loadsd
+
+IMAGES = $(FUZIX_ROOT)/Images/$(TARGET)
+
+diskimage: loadsd
+	# Make a blank disk image with partition
+	dd if=$(FUZIX_ROOT)/Standalone/filesystem-src/parttab.40M of=$(IMAGES)/sd.img bs=40017920 conv=sync
+	# Add the bootstrap loader
+	dd if=loadsd of=$(IMAGES)/sd.img conv=notrunc
+	# Add the file system
+	dd if=$(IMAGES)/filesys.img of=$(IMAGES)/sd.img bs=512 seek=2048 conv=notrunc
+	# Add the kernel
+	dd if=../../fuzix.bin of=$(IMAGES)/sd.img bs=512 seek=1 conv=notrunc

Kernel/platform/platform-minim8/README

@@ -0,0 +1,50 @@
+Fuzix for the Mini11/M8 derived from the Mini11
+
+This is a 68HC11, 2K of ROM at F800-FFFF (fixed) and 512K of RAM with a latch
+allowing the lower and upper 32K to be banked individually.
+
+The normal setup is an SD card on the SPI and the onboard serial at 9600 baud
+with a 7.3728MHz clock.
+
+Memory mapping
+
+Kernel (bank 0)
+	0x0000-0x00FF	Direct page (kernel)
+	0x0100-0x01FF	Loader space for now (can be reclaimed later)
+	0x0200-0xDFFF	Kernel
+	0xE200-0xEDFF	Common
+	0xEE00-0xEEFF	SCI serial buffers (set in m8.S)
+	0xEF00-0xEFFF	Vectors and firmware glue
+	0xF000-0xF03F	Internal I/O (only I/O)
+	0xF040-0xF1FF	Internal common RAM (but only 256 bytes on 68HC11Ax)
+	0xF200-0xF3FF	Gap
+	0xF400-0xF7FF	External I/O (not yet used)
+	0xF800-0xFFFF	ROM / memory latch
+
+In user space
+
+	0x0000-0x00FF	Direct page (user)
+	0x0100-0xDDFF	User space
+	0xDE00-0xDFFF	Udata stash
+	0xE000-0xEFFF	Common
+	0xF000-0xF03F   Internal I/O
+	0xF040-0xF1FF	Internal RAM (unbankable)
+
+This requires a thunked 68HC11 model. We pack helper data in the common
+memory and as we have so little we copy common code into each bank to
+have the same effect.
+
+There is a fair bit of space in the kernel and common maps and some holes that
+could also be tidied up if needed.
+
+TODO
+
+Would it make sense to compact the DP usage and overlap the udata at
+0x0080 in the kernel map with kernel DP at 0x00 ? This would turn a lot
+of accesses into DP mode
+
+Optimize fork and other copiers. Several could be a chunk faster with
+more self modifying code and also by using the upper/lower split for the bits
+that can be accessed via both windows.
+
+Add SPI mux support and WizNet 5500 for internet

Kernel/platform/platform-minim8/commonmem.S

@@ -0,0 +1,94 @@
+;
+;	Common space for stacks and user data
+;
+        ; exported symbols
+        .globl ub
+        .globl udata
+        .globl kstack_top
+        .globl istack_top
+        .globl istack_switched_sp
+
+	.section .data
+
+;
+;	The stacks are a bit odd. The stack pointer points to the next byte
+;	that will be written on a push so we want the top to be the last
+;	byte inclusive, not exclusive as on most processors.
+;
+;	.ds is in words for this assembler ????
+;
+ub:    ; first 512 bytes: starts with struct u_block, with the kernel stack working down from above
+udata:
+kstack_base:
+	.ds 255,0
+	.byte 0
+kstack_top:
+	.byte 0
+
+istack_base:
+	.ds 126,0
+	.byte 0
+istack_top:
+	.byte 0
+istack_switched_sp: .word 0
+
+;
+;	We have a tiny writable common area in the internal ram
+;
+	.section .commondata
+
+	.globl shared_sp
+	.globl shared_syscall
+	.globl shared_map
+	.globl shared_mlatch
+	.globl shared_argn
+	.globl shared_argn1
+	.globl shared_argn2
+	.globl shared_argn3
+	.globl shared_retval
+	.globl shared_error
+	.globl shared_signal
+	.globl shared_sigvec
+	.globl shared_preempt
+	.globl int_stack
+	.globl syscall_stack
+	.globl sci_stack
+
+shared_sp:
+	.word	0
+shared_syscall:
+	.byte	0
+shared_map:
+	.byte	0
+shared_mlatch:
+	.byte	0
+shared_argn:
+	.word	0
+shared_argn1:
+	.word	0
+shared_argn2:
+	.word	0
+shared_argn3:
+	.word	0
+shared_retval:
+	.word	0
+shared_error:
+	.word	0
+shared_signal:
+	.byte	0
+shared_sigvec:
+	.word	0
+shared_preempt:
+	.byte	0
+	.ds	16		; words
+int_stack:
+	.byte	0
+
+	.ds	16
+
+syscall_stack:
+	.byte	0
+
+	.ds	16		; Stack for serial interrupt
+sci_stack:
+	.byte	0

Kernel/platform/platform-minim8/config.h

@@ -0,0 +1,78 @@
+/* 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
+/* Acct syscall support */
+#undef CONFIG_ACCT
+/* Multiple processes in memory at once */
+#define CONFIG_MULTI
+
+#define CONFIG_BANK_FIXED
+#define MAX_MAPS 	7
+#define MAP_SIZE	0xE000
+#define CONFIG_BANKS	1
+
+/* Permit large I/O requests to bypass cache and go direct to userspace */
+#define CONFIG_LARGE_IO_DIRECT(x)	1
+
+/* Arguments are tricky. The 680x binaries stack one way the 68HC11 the other.
+   We deal with that in the syscall stubs and in crt0 */
+#define CONFIG_CALL_R2L
+
+#define TICKSPERSEC 10	    /* Ticks per second */
+
+#define MAPBASE	    0x0000  /* We map from 0 */
+#define PROGBASE    0x0000  /* also data base */
+#define PROGLOAD    0x0100
+#define PROGTOP     0xDE00  /* udata stash at DE-DF */
+
+#define SWAPDEV     (swap_dev)	/* A variable for dynamic, or a device major/minor */
+extern uint16_t swap_dev;
+/* We swap a range including the internal I/O window. This is safe because we
+   map the memory into the swap window not directly */
+#define SWAP_SIZE   0x70 	/* 56K in blocks (prog + udata) */
+#define SWAPBASE    0x0000	/* start at the base of user mem */
+#define SWAPTOP	    0xE000	/* Swap out udata and program */
+#define MAX_SWAPS   16	    	/* We will size if from the partition */
+/* Swap will be set up when a suitably labelled partition is seen */
+#define CONFIG_DYNAMIC_SWAP
+/*
+ *	When the kernel swaps something it needs to map the right page into
+ *	memory using map_for_swap and then turn the user address into a
+ *	physical address. We use the second 16K window.
+ */
+#define swap_map(x)	((uint8_t *)(x))
+
+#define CONFIG_TD_NUM	1
+#define CONFIG_TD_SD
+#define TD_SD_NUM	1
+
+#define BOOT_TTY 513        /* Set this to default device for stdio, stderr */
+
+/* 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 1
+#define TTYDEV   BOOT_TTY /* Device used by kernel for messages, panics */
+#define NBUFS    5        /* Number of block buffers */
+#define NMOUNTS	 2	  /* Number of mounts at a time */
+
+#define CONFIG_NET
+#define CONFIG_NET_WIZNET
+#define CONFIG_NET_W5500
+
+#define plt_discard()
+#define plt_copyright()
+
+#define BOOTDEVICENAMES "hd#"
+
+/* 68HC11 specific stuff */
+#define IOBASE	0xF000
+
+#define DP_BASE 0x0000
+#define DP_SIZE 0x00C0	/* C0-FF is for the kernel */
+
+#define TTY_INIT_BAUD	B9600

Kernel/platform/platform-minim8/crt0.S

@@ -0,0 +1,40 @@
+;
+;	So we end up first in the image
+;
+
+		.section .text
+
+entry:
+		sei			; interrupts off
+		lds #kstack_top		; C stack
+
+		; Clear the udata (probably not needed as we did the move
+		ldx #udata
+wipeud:
+		clr 0,x
+		inx
+		cpx #istack_switched_sp
+		bne wipeud
+
+		ldx #__bss_start
+		ldd #__bss_size
+bss_wipe:	clr ,x
+		inx
+		subd #1
+		bne bss_wipe
+
+gogogo:
+		jsr init_early
+		jsr init_hardware
+		jsr fuzix_main		; Should never return
+		sei			; Spin
+stop:		jmp stop
+
+
+;
+;	Force our custom sections to be allocated so they appear in the
+;	final binary. That was fun to find....
+;
+		.section .discard,"a"
+		.section .common,"a"
+		.section .commondata,"a"

Kernel/platform/platform-minim8/devices.c

@@ -0,0 +1,35 @@
+#include <kernel.h>
+#include <version.h>
+#include <kdata.h>
+#include <devsys.h>
+#include <tinydisk.h>
+#include <tty.h>
+#include <devtty.h>
+
+struct devsw dev_tab[] =  /* The device driver switch table */
+{
+// minor    open         close        read      write       ioctl
+// -----------------------------------------------------------------
+  /* 0: /dev/hd - block device interface */
+  {  td_open,       no_close,   td_read,        td_write,	td_ioctl},
+  /* 1: /dev/fd - Floppy disk block devices */
+  {  no_open,	    no_close,	no_rdwr,	no_rdwr,	no_ioctl},
+  /* 2: /dev/tty	TTY devices */
+  {  tty_open,     tty_close,   tty_read,  tty_write,  tty_ioctl },
+  /* 3: /dev/lpr	Printer devices */
+  {  no_open,     no_close,   no_rdwr,   no_rdwr,  no_ioctl  },
+  /* 4: /dev/mem etc	System devices (one offs) */
+  {  no_open,      no_close,    sys_read, sys_write, sys_ioctl  },
+  /* Pack to 7 with nxio if adding private devices and start at 8 */
+};
+
+bool validdev(uint16_t dev)
+{
+    /* This is a bit uglier than needed but the right hand side is
+       a constant this way */
+    if(dev > ((sizeof(dev_tab)/sizeof(struct devsw)) << 8) - 1)
+	return false;
+    else
+        return true;
+}
+