ref: 9f76a7f6819ac04552b4fb6588156f3e4089d1d7
dir: /os/boot/pc/devfloppy.c/
#include <u.h>
#include "lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "ureg.h"
#include "fs.h"
#include "devfloppy.h"
/* Intel 82077A (8272A compatible) floppy controller */
/* This module expects the following functions to be defined
* elsewhere:
*
* inb()
* outb()
* floppyexec()
* floppyeject()
* floppysetup0()
* floppysetup1()
* dmainit()
* dmasetup()
* dmaend()
*
* On DMA systems, floppyexec() should be an empty function;
* on non-DMA systems, dmaend() should be an empty function;
* dmasetup() may enforce maximum transfer sizes.
*/
enum {
/* file types */
Qdir= 0,
Qdata= (1<<2),
Qctl= (2<<2),
Qmask= (3<<2),
DMAchan= 2, /* floppy dma channel */
};
#define DPRINT if(0)print
FType floppytype[] =
{
{ "3½HD", T1440kb, 512, 18, 2, 1, 80, 0x1B, 0x54, 0, },
{ "3½DD", T1440kb, 512, 9, 2, 1, 80, 0x1B, 0x54, 2, },
{ "3½DD", T720kb, 512, 9, 2, 1, 80, 0x1B, 0x54, 2, },
{ "5¼HD", T1200kb, 512, 15, 2, 1, 80, 0x2A, 0x50, 0, },
{ "5¼DD", T1200kb, 512, 9, 2, 2, 40, 0x2A, 0x50, 1, },
{ "ATT3B1", T1200kb, 512, 8, 2, 2, 48, 0x2A, 0x50, 1, },
{ "5¼DD", T360kb, 512, 9, 2, 1, 40, 0x2A, 0x50, 2, },
};
/*
* bytes per sector encoding for the controller.
* - index for b2c is is (bytes per sector/128).
* - index for c2b is code from b2c
*/
static int b2c[] =
{
[1] 0,
[2] 1,
[4] 2,
[8] 3,
};
static int c2b[] =
{
128,
256,
512,
1024,
};
FController fl;
#define MOTORBIT(i) (1<<((i)+4))
/*
* predeclared
*/
static int cmddone(void*);
static void floppyformat(FDrive*, char*);
static void floppykproc(void*);
static void floppypos(FDrive*,long);
static int floppyrecal(FDrive*);
static int floppyresult(void);
static void floppyrevive(void);
static vlong pcfloppyseek(FDrive*, vlong);
static int floppysense(void);
static void floppywait(int);
static long floppyxfer(FDrive*, int, void*, long, long);
static void
fldump(void)
{
DPRINT("sra %ux srb %ux dor %ux msr %ux dir %ux\n", inb(Psra), inb(Psrb),
inb(Pdor), inb(Pmsr), inb(Pdir));
}
static void
floppyalarm(Alarm* a)
{
FDrive *dp;
for(dp = fl.d; dp < &fl.d[fl.ndrive]; dp++){
if((fl.motor&MOTORBIT(dp->dev)) && TK2SEC(m->ticks - dp->lasttouched) > 5)
floppyoff(dp);
}
alarm(5*1000, floppyalarm, 0);
cancel(a);
}
/*
* set floppy drive to its default type
*/
static void
floppysetdef(FDrive *dp)
{
FType *t;
for(t = floppytype; t < &floppytype[nelem(floppytype)]; t++)
if(dp->dt == t->dt){
dp->t = t;
break;
}
}
static void
_floppydetach(void)
{
/*
* stop the motors
*/
fl.motor = 0;
delay(10);
outb(Pdor, fl.motor | Fintena | Fena);
delay(10);
}
int
floppyinit(void)
{
FDrive *dp;
FType *t;
ulong maxtsize;
int mask;
dmainit(DMAchan);
floppysetup0(&fl);
/*
* init dependent parameters
*/
maxtsize = 0;
for(t = floppytype; t < &floppytype[nelem(floppytype)]; t++){
t->cap = t->bytes * t->heads * t->sectors * t->tracks;
t->bcode = b2c[t->bytes/128];
t->tsize = t->bytes * t->sectors;
if(maxtsize < t->tsize)
maxtsize = t->tsize;
}
fl.selected = fl.d;
floppydetach = _floppydetach;
floppydetach();
/*
* init drives
*/
mask = 0;
for(dp = fl.d; dp < &fl.d[fl.ndrive]; dp++){
dp->dev = dp - fl.d;
if(dp->dt == Tnone)
continue;
mask |= 1<<dp->dev;
floppysetdef(dp);
dp->cyl = -1; /* because we don't know */
dp->cache = (uchar*)xspanalloc(maxtsize, BY2PG, 64*1024);
dp->ccyl = -1;
dp->vers = 0;
dp->maxtries = 5;
}
/*
* first operation will recalibrate
*/
fl.confused = 1;
floppysetup1(&fl);
/* to turn the motor off when inactive */
alarm(5*1000, floppyalarm, 0);
return mask;
}
void
floppyinitdev(int i, char *name)
{
if(i >= fl.ndrive)
panic("floppyinitdev");
sprint(name, "fd%d", i);
}
void
floppyprintdevs(int i)
{
if(i >= fl.ndrive)
panic("floppyprintdevs");
print(" fd%d", i);
}
int
floppyboot(int dev, char *file, Boot *b)
{
Fs *fs;
if(strncmp(file, "dos!", 4) == 0)
file += 4;
else if(strchr(file, '!') || strcmp(file, "")==0) {
print("syntax is fd0!file\n");
return -1;
}
fs = floppygetfspart(dev, "dos", 1);
if(fs == nil)
return -1;
return fsboot(fs, file, b);
}
void
floppyprintbootdevs(int dev)
{
print(" fd%d", dev);
}
/*
* check if the floppy has been replaced under foot. cause
* an error if it has.
*
* a seek and a read clears the condition. this was determined
* experimentally, there has to be a better way.
*
* if the read fails, cycle through the possible floppy
* density till one works or we've cycled through all
* possibilities for this drive.
*/
static int
changed(FDrive *dp)
{
FType *start;
/*
* if floppy has changed or first time through
*/
if((inb(Pdir)&Fchange) || dp->vers == 0){
DPRINT("changed\n");
fldump();
dp->vers++;
floppysetdef(dp);
dp->maxtries = 3;
start = dp->t;
/* flopppyon fails if there's no drive */
dp->confused = 1; /* make floppyon recal */
if(floppyon(dp) < 0)
return -1;
pcfloppyseek(dp, dp->t->heads*dp->t->tsize);
while(floppyxfer(dp, Fread, dp->cache, 0, dp->t->tsize) <= 0){
/*
* if the xfer attempt doesn't clear the changed bit,
* there's no floppy in the drive
*/
if(inb(Pdir)&Fchange)
return -1;
while(++dp->t){
if(dp->t == &floppytype[nelem(floppytype)])
dp->t = floppytype;
if(dp->dt == dp->t->dt)
break;
}
/* flopppyon fails if there's no drive */
if(floppyon(dp) < 0)
return -1;
DPRINT("changed: trying %s\n", dp->t->name);
fldump();
if(dp->t == start)
return -1;
}
}
return 0;
}
static int
readtrack(FDrive *dp, int cyl, int head)
{
int i, nn, sofar;
ulong pos;
nn = dp->t->tsize;
if(dp->ccyl==cyl && dp->chead==head)
return nn;
pos = (cyl*dp->t->heads+head) * nn;
for(sofar = 0; sofar < nn; sofar += i){
dp->ccyl = -1;
i = floppyxfer(dp, Fread, dp->cache + sofar, pos + sofar, nn - sofar);
if(i <= 0)
return -1;
}
dp->ccyl = cyl;
dp->chead = head;
return nn;
}
long
floppyread(Fs *fs, void *a, long n)
{
FDrive *dp;
long rv, offset;
int sec, head, cyl;
long len;
uchar *aa;
aa = a;
dp = &fl.d[fs->dev];
offset = dp->offset;
floppyon(dp);
if(changed(dp))
return -1;
for(rv = 0; rv < n; rv += len){
/*
* all xfers come out of the track cache
*/
dp->len = n - rv;
floppypos(dp, offset+rv);
cyl = dp->tcyl;
head = dp->thead;
len = dp->len;
sec = dp->tsec;
if(readtrack(dp, cyl, head) < 0)
break;
memmove(aa+rv, dp->cache + (sec-1)*dp->t->bytes, len);
}
dp->offset = offset+rv;
return rv;
}
void*
floppygetfspart(int i, char *name, int chatty)
{
static Fs fs;
if(strcmp(name, "dos") != 0){
if(chatty)
print("unknown partition fd%d!%s (use fd%d!dos)\n", i, name, i);
return nil;
}
fs.dev = i;
fs.diskread = floppyread;
fs.diskseek = floppyseek;
/* sometimes we get spurious errors and doing it again works */
if(dosinit(&fs) < 0 && dosinit(&fs) < 0){
if(chatty)
print("fd%d!%s does not contain a FAT file system\n", i, name);
return nil;
}
return &fs;
}
static int
return0(void*)
{
return 0;
}
static void
timedsleep(int (*f)(void*), void* arg, int ms)
{
int s;
ulong end;
end = m->ticks + 1 + MS2TK(ms);
while(m->ticks < end && !(*f)(arg)){
s = spllo();
delay(10);
splx(s);
}
}
/*
* start a floppy drive's motor.
*/
static int
floppyon(FDrive *dp)
{
int alreadyon;
int tries;
if(fl.confused)
floppyrevive();
/* start motor and select drive */
dp->lasttouched = m->ticks;
alreadyon = fl.motor & MOTORBIT(dp->dev);
if(!alreadyon){
fl.motor |= MOTORBIT(dp->dev);
outb(Pdor, fl.motor | Fintena | Fena | dp->dev);
/* wait for drive to spin up */
timedsleep(return0, 0, 750);
/* clear any pending interrupts */
floppysense();
}
/* set transfer rate */
if(fl.rate != dp->t->rate){
fl.rate = dp->t->rate;
outb(Pdsr, fl.rate);
}
/* get drive to a known cylinder */
if(dp->confused)
for(tries = 0; tries < 4; tries++)
if(floppyrecal(dp) >= 0)
break;
dp->lasttouched = m->ticks;
fl.selected = dp;
if(dp->confused)
return -1;
return 0;
}
/*
* stop the floppy if it hasn't been used in 5 seconds
*/
static void
floppyoff(FDrive *dp)
{
fl.motor &= ~MOTORBIT(dp->dev);
outb(Pdor, fl.motor | Fintena | Fena | dp->dev);
}
/*
* send a command to the floppy
*/
static int
floppycmd(void)
{
int i;
int tries;
fl.nstat = 0;
for(i = 0; i < fl.ncmd; i++){
for(tries = 0; ; tries++){
if((inb(Pmsr)&(Ffrom|Fready)) == Fready)
break;
if(tries > 1000){
DPRINT("cmd %ux can't be sent (%d)\n", fl.cmd[0], i);
fldump();
/* empty fifo, might have been a bad command */
floppyresult();
return -1;
}
microdelay(1);
}
outb(Pfdata, fl.cmd[i]);
}
return 0;
}
/*
* get a command result from the floppy
*
* when the controller goes ready waiting for a command
* (instead of sending results), we're done
*
*/
static int
floppyresult(void)
{
int i, s;
int tries;
/* get the result of the operation */
for(i = 0; i < sizeof(fl.stat); i++){
/* wait for status byte */
for(tries = 0; ; tries++){
s = inb(Pmsr)&(Ffrom|Fready);
if(s == Fready){
fl.nstat = i;
return fl.nstat;
}
if(s == (Ffrom|Fready))
break;
if(tries > 1000){
DPRINT("floppyresult: %d stats\n", i);
fldump();
fl.confused = 1;
return -1;
}
microdelay(1);
}
fl.stat[i] = inb(Pfdata);
}
fl.nstat = sizeof(fl.stat);
return fl.nstat;
}
/*
* calculate physical address of a logical byte offset into the disk
*
* truncate dp->length if it crosses a track boundary
*/
static void
floppypos(FDrive *dp, long off)
{
int lsec;
int ltrack;
int end;
lsec = off/dp->t->bytes;
ltrack = lsec/dp->t->sectors;
dp->tcyl = ltrack/dp->t->heads;
dp->tsec = (lsec % dp->t->sectors) + 1;
dp->thead = (lsec/dp->t->sectors) % dp->t->heads;
/*
* can't read across track boundaries.
* if so, decrement the bytes to be read.
*/
end = (ltrack+1)*dp->t->sectors*dp->t->bytes;
if(off+dp->len > end)
dp->len = end - off;
}
/*
* get the interrupt cause from the floppy.
*/
static int
floppysense(void)
{
fl.ncmd = 0;
fl.cmd[fl.ncmd++] = Fsense;
if(floppycmd() < 0)
return -1;
if(floppyresult() < 2){
DPRINT("can't read sense response\n");
fldump();
fl.confused = 1;
return -1;
}
return 0;
}
static int
cmddone(void *a)
{
USED(a);
return fl.ncmd == 0;
}
/*
* Wait for a floppy interrupt. If none occurs in 5 seconds, we
* may have missed one. This only happens on some portables which
* do power management behind our backs. Call the interrupt
* routine to try to clear any conditions.
*/
static void
floppywait(int slow)
{
timedsleep(cmddone, 0, slow ? 5000 : 1000);
if(!cmddone(0)){
floppyintr(0);
fl.confused = 1;
}
}
/*
* we've lost the floppy position, go to cylinder 0.
*/
static int
floppyrecal(FDrive *dp)
{
dp->ccyl = -1;
dp->cyl = -1;
fl.ncmd = 0;
fl.cmd[fl.ncmd++] = Frecal;
fl.cmd[fl.ncmd++] = dp->dev;
if(floppycmd() < 0)
return -1;
floppywait(1);
if(fl.nstat < 2){
DPRINT("recalibrate: confused %ux\n", inb(Pmsr));
fl.confused = 1;
return -1;
}
if((fl.stat[0] & (Codemask|Seekend)) != Seekend){
DPRINT("recalibrate: failed\n");
dp->confused = 1;
return -1;
}
dp->cyl = fl.stat[1];
if(dp->cyl != 0){
DPRINT("recalibrate: wrong cylinder %d\n", dp->cyl);
dp->cyl = -1;
dp->confused = 1;
return -1;
}
dp->confused = 0;
return 0;
}
/*
* if the controller or a specific drive is in a confused state,
* reset it and get back to a kown state
*/
static void
floppyrevive(void)
{
FDrive *dp;
/*
* reset the controller if it's confused
*/
if(fl.confused){
DPRINT("floppyrevive in\n");
fldump();
/* reset controller and turn all motors off */
splhi();
fl.ncmd = 1;
fl.cmd[0] = 0;
outb(Pdor, 0);
delay(10);
outb(Pdor, Fintena|Fena);
delay(10);
spllo();
fl.motor = 0;
fl.confused = 0;
floppywait(0);
/* mark all drives in an unknown state */
for(dp = fl.d; dp < &fl.d[fl.ndrive]; dp++)
dp->confused = 1;
/* set rate to a known value */
outb(Pdsr, 0);
fl.rate = 0;
DPRINT("floppyrevive out\n");
fldump();
}
}
/*
* seek to the target cylinder
*
* interrupt, no results
*/
static vlong
pcfloppyseek(FDrive *dp, vlong off)
{
floppypos(dp, off);
if(dp->cyl == dp->tcyl){
dp->offset = off;
return off;
}
dp->cyl = -1;
fl.ncmd = 0;
fl.cmd[fl.ncmd++] = Fseek;
fl.cmd[fl.ncmd++] = (dp->thead<<2) | dp->dev;
fl.cmd[fl.ncmd++] = dp->tcyl * dp->t->steps;
if(floppycmd() < 0)
return -1;
floppywait(1);
if(fl.nstat < 2){
DPRINT("seek: confused\n");
fl.confused = 1;
return -1;
}
if((fl.stat[0] & (Codemask|Seekend)) != Seekend){
DPRINT("seek: failed\n");
dp->confused = 1;
return -1;
}
dp->cyl = dp->tcyl;
dp->offset = off;
DPRINT("seek to %d succeeded\n", dp->offset);
return dp->offset;
}
/*
* read or write to floppy. try up to three times.
*/
static long
floppyxfer(FDrive *dp, int cmd, void *a, long off, long n)
{
long offset;
int tries;
if(off >= dp->t->cap)
return 0;
if(off + n > dp->t->cap)
n = dp->t->cap - off;
/* retry on error (until it gets ridiculous) */
for(tries = 0; tries < dp->maxtries; tries++){
dp->len = n;
if(pcfloppyseek(dp, off) < 0){
DPRINT("xfer: seek failed\n");
dp->confused = 1;
continue;
}
/*
* set up the dma (dp->len may be trimmed)
*/
dp->len = dmasetup(DMAchan, a, dp->len, cmd==Fread);
if(dp->len < 0){
buggery:
dmaend(DMAchan);
continue;
}
/*
* start operation
*/
fl.ncmd = 0;
fl.cmd[fl.ncmd++] = cmd | (dp->t->heads > 1 ? Fmulti : 0);
fl.cmd[fl.ncmd++] = (dp->thead<<2) | dp->dev;
fl.cmd[fl.ncmd++] = dp->tcyl;
fl.cmd[fl.ncmd++] = dp->thead;
fl.cmd[fl.ncmd++] = dp->tsec;
fl.cmd[fl.ncmd++] = dp->t->bcode;
fl.cmd[fl.ncmd++] = dp->t->sectors;
fl.cmd[fl.ncmd++] = dp->t->gpl;
fl.cmd[fl.ncmd++] = 0xFF;
if(floppycmd() < 0)
goto buggery;
/*
* give bus to DMA, floppyintr() will read result
*/
floppywait(0);
dmaend(DMAchan);
/*
* check for errors
*/
if(fl.nstat < 7){
DPRINT("xfer: confused\n");
fl.confused = 1;
continue;
}
if((fl.stat[0] & Codemask)!=0 || fl.stat[1] || fl.stat[2]){
DPRINT("xfer: failed %ux %ux %ux\n", fl.stat[0],
fl.stat[1], fl.stat[2]);
DPRINT("offset %lud len %ld\n", off, dp->len);
if((fl.stat[0]&Codemask)==Cmdexec && fl.stat[1]==Overrun){
DPRINT("DMA overrun: retry\n");
} else
dp->confused = 1;
continue;
}
/*
* check for correct cylinder
*/
offset = fl.stat[3] * dp->t->heads + fl.stat[4];
offset = offset*dp->t->sectors + fl.stat[5] - 1;
offset = offset * c2b[fl.stat[6]];
if(offset != off+dp->len){
DPRINT("xfer: ends on wrong cyl\n");
dp->confused = 1;
continue;
}
dp->lasttouched = m->ticks;
dp->maxtries = 20;
return dp->len;
}
return -1;
}
/*
void
floppymemwrite(void)
{
int i;
int n;
uchar *a;
FDrive *dp;
dp = &fl.d[0];
a = (uchar*)0x80000000;
n = 0;
while(n < 1440*1024){
i = floppyxfer(dp, Fwrite, a+n, n, 1440*1024-n);
if(i <= 0)
break;
n += i;
}
print("floppymemwrite wrote %d bytes\n", n);
splhi(); for(;;);
}
*/
static void
floppyintr(Ureg *ur)
{
USED(ur);
switch(fl.cmd[0]&~Fmulti){
case Fread:
case Fwrite:
case Fformat:
case Fdumpreg:
floppyresult();
break;
case Fseek:
case Frecal:
default:
floppysense(); /* to clear interrupt */
break;
}
fl.ncmd = 0;
}