From: Alan Cox <alan@linux.intel.com>
Date: Mon, 1 Jun 2015 19:47:21 +0000 (+0100)
Subject: trs80: first cut at drivewire support
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=361648dc88d79c7cb6769902d7e6dad85475e17e;p=FUZIX.git

trs80: first cut at drivewire support

Limited to a whopping 19200 baud, and assumes you set up the /dev/tty3 port as you want then run drivewire (don't mix and match!)

Needs optimising, actually testing once I've fixed the emulator to do better
serial proxying.
---

diff --git a/Kernel/platform-trs80/Makefile b/Kernel/platform-trs80/Makefile
index 82c1e02f..c3ce2e82 100644
--- a/Kernel/platform-trs80/Makefile
+++ b/Kernel/platform-trs80/Makefile
@@ -4,12 +4,17 @@ CSRCS += devices.c main.c
 DISCARD_CSRCS = discard.c devhd_discard.c
 
 ASRCS = trs80.s crt0.s
-ASRCS += tricks.s commonmem.s floppy.s
+ASRCS += tricks.s commonmem.s floppy.s drivewire.s
+
+DSRCS = ../dev/devdw.c
 
 COBJS = $(CSRCS:.c=.rel)
 AOBJS = $(ASRCS:.s=.rel)
 DISCARD_COBJS = $(DISCARD_CSRCS:.c=.rel)
-OBJS  = $(COBJS) $(AOBJS) $(DISCARD_COBJS)
+DOBJS = $(patsubst ../dev/%.c,%.rel, $(DSRCS))
+OBJS  = $(COBJS) $(AOBJS) $(DISCARD_COBJS) $(DOBJS)
+
+CROSS_CCOPTS += -I../dev/
 
 JUNK = $(CSRCS:.c=.lst) $(CSRCS:.c=.asm) $(CSRCS:.c=.sym) $(ASRCS:.s=.lst) $(ASRCS:.s=.sym) $(CSRCS:.c=.rst) $(ASRCS:.s=.rst)
 
@@ -21,6 +26,9 @@ $(COBJS): %.rel: %.c
 $(AOBJS): %.rel: %.s
 	$(CROSS_AS) $(ASOPTS) $<
 
+$(DOBJS): %.rel: ../dev/%.c
+	$(CROSS_CC) $(CROSS_CCOPTS) -c $<
+
 $(DISCARD_COBJS): %.rel: %.c
 	$(CROSS_CC) $(CROSS_CCOPTS) $(CROSS_CC_SEGDISC) -c $<
 
diff --git a/Kernel/platform-trs80/devices.c b/Kernel/platform-trs80/devices.c
index ad1b01fa..1b804020 100644
--- a/Kernel/platform-trs80/devices.c
+++ b/Kernel/platform-trs80/devices.c
@@ -6,6 +6,7 @@
 #include <devhd.h>
 #include <devsys.h>
 #include <devlpr.h>
+#include <devdw.h>
 #include <vt.h>
 #include <devtty.h>
 #include <devgfx.h>
@@ -23,6 +24,11 @@ struct devsw dev_tab[] =  /* The device driver switch table */
   /* 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 */
+  {  nxio_open,     no_close,    no_rdwr,   no_rdwr,   no_ioctl },
+  {  nxio_open,     no_close,    no_rdwr,   no_rdwr,   no_ioctl },
+  {  nxio_open,     no_close,    no_rdwr,   no_rdwr,   no_ioctl },
+  /* 8: /dev/dw		DriveWire remote disk images */
+  {  dw_open,      no_close,    dw_read,   dw_write,  no_ioctl },
 };
 
 bool validdev(uint16_t dev)
diff --git a/Kernel/platform-trs80/drivewire.s b/Kernel/platform-trs80/drivewire.s
new file mode 100644
index 00000000..c84b3278
--- /dev/null
+++ b/Kernel/platform-trs80/drivewire.s
@@ -0,0 +1,153 @@
+	.module drivewire
+
+	.globl _dw_operation
+	.globl _dw_reset
+
+	.globl map_process_a
+	.globl map_kernel
+
+
+
+	.area _COMMONMEM
+
+	; dw_reset(driveptr)
+_dw_reset:
+	ret
+
+	; dw_operation(cmdblock, driveptr)
+_dw_operation:
+	pop bc		; return
+	pop iy		; cmdblock
+	pop de		; driveptr
+	push de
+	push iy
+	push bc
+
+	ld b, 5(iy)	; page map
+	call map_process_a
+	ld h, 3(iy)	; pointer
+	ld l, 4(iy)
+	ld b, 1(iy)
+	ld c, 2(iy)
+	xor a
+	cp (iy)
+	ld a, (de)
+	jr nz, is_write
+	call dw_read_sector
+dw_op_ret:
+	ld hl, #0
+	jr nc, dw_op_ok
+	dec hl
+dw_op_ok:
+	jp map_kernel
+is_write:
+	call dw_write_sector
+	jr dw_op_ret
+
+; Entry A = command
+; Exit BCD = 0
+
+dw_hdr:
+	call txbyte
+	ld a, (de)	; drive
+	call txbyte
+	xor a		; LSN 23-16 = 0
+	call txbyte
+	ld a, b		; sector high
+	call txbyte
+	ld a, c		; sector low	
+	call txbyte
+	ld b, #0
+	ld d, b		;checkum starts 0
+	ld e, b
+	ret
+
+dw_write_sector:
+	ld a, #0x57		; WRITE
+	call dw_hdr
+payload1:
+	ld a, e
+	add (hl)
+	ld e, a
+	ld a, d
+	adc #0
+	ld d, a
+	ld a, (hl)
+	inc hl
+	call txbyte
+	djnz payload1
+	ld a, d
+	call txbyte
+	ld a, e
+	call txbyte
+	call rxbyte
+	ret
+
+dw_read_sector:
+	ld a, #0xD2		; READEX
+	call dw_hdr
+	call rxbyte
+	ret c
+	or a
+	jr nz, error_ret
+;
+;	256 receive bytes
+;
+payload2:
+	call rxbyte
+	ret c
+	ld (hl), a
+	inc hl
+	ld a, (hl)
+	add e
+	ld e, a
+	ld a, #0
+	add d
+	ld d, a
+	djnz payload2
+	ld a, d
+	call txbyte
+	ld a, e
+	call txbyte
+	call rxbyte
+	ret c
+	or a
+	ret z
+	; We could be smarter about error codes and reporting ?
+error_ret:
+	scf
+	ret
+
+;
+;	Serial logic, polled interrupts off so we can do a reliable 19200
+;	baud (hardware limit)
+;
+txbyte:
+	in a, (0xEA)
+	bit 6, a
+	jr z, txbyte
+	out (0xEB), a
+	ret
+;
+;	We poll for receive in this mode as interrupts are off and we want
+;	*speed*
+;
+rxbyte:
+	; Loop time is 56 clocks so ~=72K loops/second
+	; we want to spin for 0.25 (Drivewire limit)
+	ld bc, #0x46
+rxbytel:
+	in a, (0xEA)		; 11
+	bit 7, a		; 8
+	jr nz, gotbyte		; 7(12)
+	dec bc			; 10
+	ld a, b			; 4
+	or c			; 4
+	jr nz, rxbytel		; 7(12)
+	scf
+	ret
+gotbyte:
+	in a, (0xEB)
+	or a
+	ret
+
diff --git a/Kernel/platform-trs80/fuzix.lnk b/Kernel/platform-trs80/fuzix.lnk
index 210e6910..da04512a 100644
--- a/Kernel/platform-trs80/fuzix.lnk
+++ b/Kernel/platform-trs80/fuzix.lnk
@@ -40,4 +40,6 @@ devsys.rel
 platform-trs80/devlpr.rel
 platform-trs80/devtty.rel
 platform-trs80/discard.rel
+platform-trs80/devdw.rel
+platform-trs80/drivewire.rel
 -e