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/*
* linux/kernel/floppy.c
*
* (C) 1991 Linus Torvalds
*/
/*
* 02.12.91 - Changed to static variables to indicate need for reset
* and recalibrate. This makes some things easier (output_byte reset
* checking etc), and means less interrupt jumping in case of errors,
* so the code is hopefully easier to understand.
*/
/*
* This file is certainly a mess. I've tried my best to get it working,
* but I don't like programming floppies, and I have only one anyway.
* Urgel. I should check for more errors, and do more graceful error
* recovery. Seems there are problems with several drives. I've tried to
* correct them. No promises.
*/
/*
* As with hd.c, all routines within this file can (and will) be called
* by interrupts, so extreme caution is needed. A hardware interrupt
* handler may not sleep, or a kernel panic will happen. Thus I cannot
* call "floppy-on" directly, but have to set a special timer interrupt
* etc.
*
* Also, I'm not certain this works on more than 1 floppy. Bugs may
* abund.
*/
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/fdreg.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/segment.h>
#define MAJOR_NR 2
#include "blk.h"
static int recalibrate = 0;
static int reset = 0;
static int seek = 0;
extern unsigned char current_DOR;
#define immoutb_p(val,port) \
__asm__("outb %0,%1\n\tjmp 1f\n1:\tjmp 1f\n1:"::"a" ((char) (val)),"i" (port))
#define TYPE(x) ((x)>>2)
#define DRIVE(x) ((x)&0x03)
/*
* Note that MAX_ERRORS=8 doesn't imply that we retry every bad read
* max 8 times - some types of errors increase the errorcount by 2,
* so we might actually retry only 5-6 times before giving up.
*/
#define MAX_ERRORS 8
/*
* globals used by 'result()'
*/
#define MAX_REPLIES 7
static unsigned char reply_buffer[MAX_REPLIES];
#define ST0 (reply_buffer[0])
#define ST1 (reply_buffer[1])
#define ST2 (reply_buffer[2])
#define ST3 (reply_buffer[3])
/*
* This struct defines the different floppy types. Unlike minix
* linux doesn't have a "search for right type"-type, as the code
* for that is convoluted and weird. I've got enough problems with
* this driver as it is.
*
* The 'stretch' tells if the tracks need to be boubled for some
* types (ie 360kB diskette in 1.2MB drive etc). Others should
* be self-explanatory.
*/
static struct floppy_struct {
unsigned int size, sect, head, track, stretch;
unsigned char gap,rate,spec1;
} floppy_type[] = {
{ 0, 0,0, 0,0,0x00,0x00,0x00 }, /* no testing */
{ 720, 9,2,40,0,0x2A,0x02,0xDF }, /* 360kB PC diskettes */
{ 2400,15,2,80,0,0x1B,0x00,0xDF }, /* 1.2 MB AT-diskettes */
{ 720, 9,2,40,1,0x2A,0x02,0xDF }, /* 360kB in 720kB drive */
{ 1440, 9,2,80,0,0x2A,0x02,0xDF }, /* 3.5" 720kB diskette */
{ 720, 9,2,40,1,0x23,0x01,0xDF }, /* 360kB in 1.2MB drive */
{ 1440, 9,2,80,0,0x23,0x01,0xDF }, /* 720kB in 1.2MB drive */
{ 2880,18,2,80,0,0x1B,0x00,0xCF }, /* 1.44MB diskette */
};
/*
* Rate is 0 for 500kb/s, 2 for 300kbps, 1 for 250kbps
* Spec1 is 0xSH, where S is stepping rate (F=1ms, E=2ms, D=3ms etc),
* H is head unload time (1=16ms, 2=32ms, etc)
*
* Spec2 is (HLD<<1 | ND), where HLD is head load time (1=2ms, 2=4 ms etc)
* and ND is set means no DMA. Hardcoded to 6 (HLD=6ms, use DMA).
*/
extern void floppy_interrupt(void);
extern char tmp_floppy_area[1024];
/*
* These are global variables, as that's the easiest way to give
* information to interrupts. They are the data used for the current
* request.
*/
static int cur_spec1 = -1;
static int cur_rate = -1;
static struct floppy_struct * floppy = floppy_type;
static unsigned char current_drive = 0;
static unsigned char sector = 0;
static unsigned char head = 0;
static unsigned char track = 0;
static unsigned char seek_track = 0;
static unsigned char current_track = 255;
static unsigned char command = 0;
unsigned char selected = 0;
struct task_struct * wait_on_floppy_select = NULL;
void floppy_deselect(unsigned int nr)
{
if (nr != (current_DOR & 3))
printk("floppy_deselect: drive not selected\n\r");
selected = 0;
wake_up(&wait_on_floppy_select);
}
/*
* floppy-change is never called from an interrupt, so we can relax a bit
* here, sleep etc. Note that floppy-on tries to set current_DOR to point
* to the desired drive, but it will probably not survive the sleep if
* several floppies are used at the same time: thus the loop.
*/
int floppy_change(unsigned int nr)
{
repeat:
floppy_on(nr);
while ((current_DOR & 3) != nr && selected)
interruptible_sleep_on(&wait_on_floppy_select);
if ((current_DOR & 3) != nr)
goto repeat;
if (inb(FD_DIR) & 0x80) {
floppy_off(nr);
return 1;
}
floppy_off(nr);
return 0;
}
#define copy_buffer(from,to) \
__asm__("cld ; rep ; movsl" \
::"c" (BLOCK_SIZE/4),"S" ((long)(from)),"D" ((long)(to)) \
:"cx","di","si")
static void setup_DMA(void)
{
long addr = (long) CURRENT->buffer;
cli();
if (addr >= 0x100000) {
addr = (long) tmp_floppy_area;
if (command == FD_WRITE)
copy_buffer(CURRENT->buffer,tmp_floppy_area);
}
/* mask DMA 2 */
immoutb_p(4|2,10);
/* output command byte. I don't know why, but everyone (minix, */
/* sanches & canton) output this twice, first to 12 then to 11 */
__asm__("outb %%al,$12\n\tjmp 1f\n1:\tjmp 1f\n1:\t"
"outb %%al,$11\n\tjmp 1f\n1:\tjmp 1f\n1:"::
"a" ((char) ((command == FD_READ)?DMA_READ:DMA_WRITE)));
/* 8 low bits of addr */
immoutb_p(addr,4);
addr >>= 8;
/* bits 8-15 of addr */
immoutb_p(addr,4);
addr >>= 8;
/* bits 16-19 of addr */
immoutb_p(addr,0x81);
/* low 8 bits of count-1 (1024-1=0x3ff) */
immoutb_p(0xff,5);
/* high 8 bits of count-1 */
immoutb_p(3,5);
/* activate DMA 2 */
immoutb_p(0|2,10);
sti();
}
static void output_byte(char byte)
{
int counter;
unsigned char status;
if (reset)
return;
for(counter = 0 ; counter < 10000 ; counter++) {
status = inb_p(FD_STATUS) & (STATUS_READY | STATUS_DIR);
if (status == STATUS_READY) {
outb(byte,FD_DATA);
return;
}
}
reset = 1;
printk("Unable to send byte to FDC\n\r");
}
static int result(void)
{
int i = 0, counter, status;
if (reset)
return -1;
for (counter = 0 ; counter < 10000 ; counter++) {
status = inb_p(FD_STATUS)&(STATUS_DIR|STATUS_READY|STATUS_BUSY);
if (status == STATUS_READY)
return i;
if (status == (STATUS_DIR|STATUS_READY|STATUS_BUSY)) {
if (i >= MAX_REPLIES)
break;
reply_buffer[i++] = inb_p(FD_DATA);
}
}
reset = 1;
printk("Getstatus times out\n\r");
return -1;
}
static void bad_flp_intr(void)
{
CURRENT->errors++;
if (CURRENT->errors > MAX_ERRORS) {
floppy_deselect(current_drive);
end_request(0);
}
if (CURRENT->errors > MAX_ERRORS/2)
reset = 1;
else
recalibrate = 1;
}
/*
* Ok, this interrupt is called after a DMA read/write has succeeded,
* so we check the results, and copy any buffers.
*/
static void rw_interrupt(void)
{
if (result() != 7 || (ST0 & 0xf8) || (ST1 & 0xbf) || (ST2 & 0x73)) {
if (ST1 & 0x02) {
printk("Drive %d is write protected\n\r",current_drive);
floppy_deselect(current_drive);
end_request(0);
} else
bad_flp_intr();
do_fd_request();
return;
}
if (command == FD_READ && (unsigned long)(CURRENT->buffer) >= 0x100000)
copy_buffer(tmp_floppy_area,CURRENT->buffer);
floppy_deselect(current_drive);
end_request(1);
do_fd_request();
}
inline void setup_rw_floppy(void)
{
setup_DMA();
do_floppy = rw_interrupt;
output_byte(command);
output_byte(head<<2 | current_drive);
output_byte(track);
output_byte(head);
output_byte(sector);
output_byte(2); /* sector size = 512 */
output_byte(floppy->sect);
output_byte(floppy->gap);
output_byte(0xFF); /* sector size (0xff when n!=0 ?) */
if (reset)
do_fd_request();
}
/*
* This is the routine called after every seek (or recalibrate) interrupt
* from the floppy controller. Note that the "unexpected interrupt" routine
* also does a recalibrate, but doesn't come here.
*/
static void seek_interrupt(void)
{
/* sense drive status */
output_byte(FD_SENSEI);
if (result() != 2 || (ST0 & 0xF8) != 0x20 || ST1 != seek_track) {
bad_flp_intr();
do_fd_request();
return;
}
current_track = ST1;
setup_rw_floppy();
}
/*
* This routine is called when everything should be correctly set up
* for the transfer (ie floppy motor is on and the correct floppy is
* selected).
*/
static void transfer(void)
{
if (cur_spec1 != floppy->spec1) {
cur_spec1 = floppy->spec1;
output_byte(FD_SPECIFY);
output_byte(cur_spec1); /* hut etc */
output_byte(6); /* Head load time =6ms, DMA */
}
if (cur_rate != floppy->rate)
outb_p(cur_rate = floppy->rate,FD_DCR);
if (reset) {
do_fd_request();
return;
}
if (!seek) {
setup_rw_floppy();
return;
}
do_floppy = seek_interrupt;
if (seek_track) {
output_byte(FD_SEEK);
output_byte(head<<2 | current_drive);
output_byte(seek_track);
} else {
output_byte(FD_RECALIBRATE);
output_byte(head<<2 | current_drive);
}
if (reset)
do_fd_request();
}
/*
* Special case - used after a unexpected interrupt (or reset)
*/
static void recal_interrupt(void)
{
output_byte(FD_SENSEI);
if (result()!=2 || (ST0 & 0xE0) == 0x60)
reset = 1;
else
recalibrate = 0;
do_fd_request();
}
void unexpected_floppy_interrupt(void)
{
output_byte(FD_SENSEI);
if (result()!=2 || (ST0 & 0xE0) == 0x60)
reset = 1;
else
recalibrate = 1;
}
static void recalibrate_floppy(void)
{
recalibrate = 0;
current_track = 0;
do_floppy = recal_interrupt;
output_byte(FD_RECALIBRATE);
output_byte(head<<2 | current_drive);
if (reset)
do_fd_request();
}
static void reset_interrupt(void)
{
output_byte(FD_SENSEI);
(void) result();
output_byte(FD_SPECIFY);
output_byte(cur_spec1); /* hut etc */
output_byte(6); /* Head load time =6ms, DMA */
do_fd_request();
}
/*
* reset is done by pulling bit 2 of DOR low for a while.
*/
static void reset_floppy(void)
{
int i;
reset = 0;
cur_spec1 = -1;
cur_rate = -1;
recalibrate = 1;
printk("Reset-floppy called\n\r");
cli();
do_floppy = reset_interrupt;
outb_p(current_DOR & ~0x04,FD_DOR);
for (i=0 ; i<100 ; i++)
__asm__("nop");
outb(current_DOR,FD_DOR);
sti();
}
static void floppy_on_interrupt(void)
{
/* We cannot do a floppy-select, as that might sleep. We just force it */
selected = 1;
if (current_drive != (current_DOR & 3)) {
current_DOR &= 0xFC;
current_DOR |= current_drive;
outb(current_DOR,FD_DOR);
add_timer(2,&transfer);
} else
transfer();
}
void do_fd_request(void)
{
unsigned int block;
seek = 0;
if (reset) {
reset_floppy();
return;
}
if (recalibrate) {
recalibrate_floppy();
return;
}
INIT_REQUEST;
floppy = (MINOR(CURRENT->dev)>>2) + floppy_type;
if (current_drive != CURRENT_DEV)
seek = 1;
current_drive = CURRENT_DEV;
block = CURRENT->sector;
if (block+2 > floppy->size) {
end_request(0);
goto repeat;
}
sector = block % floppy->sect;
block /= floppy->sect;
head = block % floppy->head;
track = block / floppy->head;
seek_track = track << floppy->stretch;
if (seek_track != current_track)
seek = 1;
sector++;
if (CURRENT->cmd == READ)
command = FD_READ;
else if (CURRENT->cmd == WRITE)
command = FD_WRITE;
else
panic("do_fd_request: unknown command");
add_timer(ticks_to_floppy_on(current_drive),&floppy_on_interrupt);
}
void floppy_init(void)
{
blk_dev[MAJOR_NR].request_fn = DEVICE_REQUEST;
set_trap_gate(0x26,&floppy_interrupt);
outb(inb_p(0x21)&~0x40,0x21);
}
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