414 lines
9.9 KiB
C
414 lines
9.9 KiB
C
#include <linux/config.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/hdreg.h>
|
|
#include <asm/system.h>
|
|
#include <asm/io.h>
|
|
#include <asm/segment.h>
|
|
|
|
/*
|
|
* This code handles all hd-interrupts, and read/write requests to
|
|
* the hard-disk. It is relatively straigthforward (not obvious maybe,
|
|
* but interrupts never are), while still being efficient, and never
|
|
* disabling interrupts (except to overcome possible race-condition).
|
|
* The elevator block-seek algorithm doesn't need to disable interrupts
|
|
* due to clever programming.
|
|
*/
|
|
|
|
/* Max read/write errors/sector */
|
|
#define MAX_ERRORS 5
|
|
#define MAX_HD 2
|
|
#define NR_REQUEST 32
|
|
|
|
/*
|
|
* This struct defines the HD's and their types.
|
|
* Currently defined for CP3044's, ie a modified
|
|
* type 17.
|
|
*/
|
|
static struct hd_i_struct{
|
|
int head,sect,cyl,wpcom,lzone,ctl;
|
|
} hd_info[]= { HD_TYPE };
|
|
|
|
#define NR_HD ((sizeof (hd_info))/(sizeof (struct hd_i_struct)))
|
|
|
|
static struct hd_struct {
|
|
long start_sect;
|
|
long nr_sects;
|
|
} hd[5*MAX_HD]={{0,0},};
|
|
|
|
static struct hd_request {
|
|
int hd; /* -1 if no request */
|
|
int nsector;
|
|
int sector;
|
|
int head;
|
|
int cyl;
|
|
int cmd;
|
|
int errors;
|
|
struct buffer_head * bh;
|
|
struct hd_request * next;
|
|
} request[NR_REQUEST];
|
|
|
|
#define IN_ORDER(s1,s2) \
|
|
((s1)->hd<(s2)->hd || (s1)->hd==(s2)->hd && \
|
|
((s1)->cyl<(s2)->cyl || (s1)->cyl==(s2)->cyl && \
|
|
((s1)->head<(s2)->head || (s1)->head==(s2)->head && \
|
|
((s1)->sector<(s2)->sector))))
|
|
|
|
static struct hd_request * this_request = NULL;
|
|
|
|
static int sorting=0;
|
|
|
|
static void do_request(void);
|
|
static void reset_controller(void);
|
|
static void rw_abs_hd(int rw,unsigned int nr,unsigned int sec,unsigned int head,
|
|
unsigned int cyl,struct buffer_head * bh);
|
|
void hd_init(void);
|
|
|
|
#define port_read(port,buf,nr) \
|
|
__asm__("cld;rep;insw"::"d" (port),"D" (buf),"c" (nr):"cx","di")
|
|
|
|
#define port_write(port,buf,nr) \
|
|
__asm__("cld;rep;outsw"::"d" (port),"S" (buf),"c" (nr):"cx","si")
|
|
|
|
extern void hd_interrupt(void);
|
|
|
|
static struct task_struct * wait_for_request=NULL;
|
|
|
|
static inline void lock_buffer(struct buffer_head * bh)
|
|
{
|
|
if (bh->b_lock)
|
|
printk("hd.c: buffer multiply locked\n");
|
|
bh->b_lock=1;
|
|
}
|
|
|
|
static inline void unlock_buffer(struct buffer_head * bh)
|
|
{
|
|
if (!bh->b_lock)
|
|
printk("hd.c: free buffer being unlocked\n");
|
|
bh->b_lock=0;
|
|
wake_up(&bh->b_wait);
|
|
}
|
|
|
|
static inline void wait_on_buffer(struct buffer_head * bh)
|
|
{
|
|
cli();
|
|
while (bh->b_lock)
|
|
sleep_on(&bh->b_wait);
|
|
sti();
|
|
}
|
|
|
|
void rw_hd(int rw, struct buffer_head * bh)
|
|
{
|
|
unsigned int block,dev;
|
|
unsigned int sec,head,cyl;
|
|
|
|
block = bh->b_blocknr << 1;
|
|
dev = MINOR(bh->b_dev);
|
|
if (dev >= 5*NR_HD || block+2 > hd[dev].nr_sects)
|
|
return;
|
|
block += hd[dev].start_sect;
|
|
dev /= 5;
|
|
__asm__("divl %4":"=a" (block),"=d" (sec):"0" (block),"1" (0),
|
|
"r" (hd_info[dev].sect));
|
|
__asm__("divl %4":"=a" (cyl),"=d" (head):"0" (block),"1" (0),
|
|
"r" (hd_info[dev].head));
|
|
rw_abs_hd(rw,dev,sec+1,head,cyl,bh);
|
|
}
|
|
|
|
/* This may be used only once, enforced by 'static int callable' */
|
|
int sys_setup(void)
|
|
{
|
|
static int callable = 1;
|
|
int i,drive;
|
|
struct partition *p;
|
|
|
|
if (!callable)
|
|
return -1;
|
|
callable = 0;
|
|
for (drive=0 ; drive<NR_HD ; drive++) {
|
|
rw_abs_hd(READ,drive,1,0,0,(struct buffer_head *) start_buffer);
|
|
if (!start_buffer->b_uptodate) {
|
|
printk("Unable to read partition table of drive %d\n\r",
|
|
drive);
|
|
panic("");
|
|
}
|
|
if (start_buffer->b_data[510] != 0x55 || (unsigned char)
|
|
start_buffer->b_data[511] != 0xAA) {
|
|
printk("Bad partition table on drive %d\n\r",drive);
|
|
panic("");
|
|
}
|
|
p = 0x1BE + (void *)start_buffer->b_data;
|
|
for (i=1;i<5;i++,p++) {
|
|
hd[i+5*drive].start_sect = p->start_sect;
|
|
hd[i+5*drive].nr_sects = p->nr_sects;
|
|
}
|
|
}
|
|
printk("Partition table%s ok.\n\r",(NR_HD>1)?"s":"");
|
|
mount_root();
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* This is the pointer to a routine to be executed at every hd-interrupt.
|
|
* Interesting way of doing things, but should be rather practical.
|
|
*/
|
|
void (*do_hd)(void) = NULL;
|
|
|
|
static int controller_ready(void)
|
|
{
|
|
int retries=1000;
|
|
|
|
while (--retries && (inb(HD_STATUS)&0xc0)!=0x40);
|
|
return (retries);
|
|
}
|
|
|
|
static int win_result(void)
|
|
{
|
|
int i=inb(HD_STATUS);
|
|
|
|
if ((i & (BUSY_STAT | READY_STAT | WRERR_STAT | SEEK_STAT | ERR_STAT))
|
|
== (READY_STAT | SEEK_STAT))
|
|
return(0); /* ok */
|
|
if (i&1) i=inb(HD_ERROR);
|
|
return (1);
|
|
}
|
|
|
|
static void hd_out(unsigned int drive,unsigned int nsect,unsigned int sect,
|
|
unsigned int head,unsigned int cyl,unsigned int cmd,
|
|
void (*intr_addr)(void))
|
|
{
|
|
register int port asm("dx");
|
|
|
|
if (drive>1 || head>15)
|
|
panic("Trying to write bad sector");
|
|
if (!controller_ready())
|
|
panic("HD controller not ready");
|
|
do_hd = intr_addr;
|
|
outb(_CTL,HD_CMD);
|
|
port=HD_DATA;
|
|
outb_p(_WPCOM,++port);
|
|
outb_p(nsect,++port);
|
|
outb_p(sect,++port);
|
|
outb_p(cyl,++port);
|
|
outb_p(cyl>>8,++port);
|
|
outb_p(0xA0|(drive<<4)|head,++port);
|
|
outb(cmd,++port);
|
|
}
|
|
|
|
static int drive_busy(void)
|
|
{
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < 100000; i++)
|
|
if (READY_STAT == (inb(HD_STATUS) & (BUSY_STAT | READY_STAT)))
|
|
break;
|
|
i = inb(HD_STATUS);
|
|
i &= BUSY_STAT | READY_STAT | SEEK_STAT;
|
|
if (i == READY_STAT | SEEK_STAT)
|
|
return(0);
|
|
printk("HD controller times out\n\r");
|
|
return(1);
|
|
}
|
|
|
|
static void reset_controller(void)
|
|
{
|
|
int i;
|
|
|
|
outb(4,HD_CMD);
|
|
for(i = 0; i < 1000; i++) nop();
|
|
outb(0,HD_CMD);
|
|
for(i = 0; i < 10000 && drive_busy(); i++) /* nothing */;
|
|
if (drive_busy())
|
|
printk("HD-controller still busy\n\r");
|
|
if((i = inb(ERR_STAT)) != 1)
|
|
printk("HD-controller reset failed: %02x\n\r",i);
|
|
}
|
|
|
|
static void reset_hd(int nr)
|
|
{
|
|
reset_controller();
|
|
hd_out(nr,_SECT,_SECT,_HEAD-1,_CYL,WIN_SPECIFY,&do_request);
|
|
}
|
|
|
|
void unexpected_hd_interrupt(void)
|
|
{
|
|
panic("Unexpected HD interrupt\n\r");
|
|
}
|
|
|
|
static void bad_rw_intr(void)
|
|
{
|
|
int i = this_request->hd;
|
|
|
|
if (this_request->errors++ >= MAX_ERRORS) {
|
|
this_request->bh->b_uptodate = 0;
|
|
unlock_buffer(this_request->bh);
|
|
wake_up(&wait_for_request);
|
|
this_request->hd = -1;
|
|
this_request=this_request->next;
|
|
}
|
|
reset_hd(i);
|
|
}
|
|
|
|
static void read_intr(void)
|
|
{
|
|
if (win_result()) {
|
|
bad_rw_intr();
|
|
return;
|
|
}
|
|
port_read(HD_DATA,this_request->bh->b_data+
|
|
512*(this_request->nsector&1),256);
|
|
this_request->errors = 0;
|
|
if (--this_request->nsector)
|
|
return;
|
|
this_request->bh->b_uptodate = 1;
|
|
this_request->bh->b_dirt = 0;
|
|
wake_up(&wait_for_request);
|
|
unlock_buffer(this_request->bh);
|
|
this_request->hd = -1;
|
|
this_request=this_request->next;
|
|
do_request();
|
|
}
|
|
|
|
static void write_intr(void)
|
|
{
|
|
if (win_result()) {
|
|
bad_rw_intr();
|
|
return;
|
|
}
|
|
if (--this_request->nsector) {
|
|
port_write(HD_DATA,this_request->bh->b_data+512,256);
|
|
return;
|
|
}
|
|
this_request->bh->b_uptodate = 1;
|
|
this_request->bh->b_dirt = 0;
|
|
wake_up(&wait_for_request);
|
|
unlock_buffer(this_request->bh);
|
|
this_request->hd = -1;
|
|
this_request=this_request->next;
|
|
do_request();
|
|
}
|
|
|
|
static void do_request(void)
|
|
{
|
|
int i,r;
|
|
|
|
if (sorting)
|
|
return;
|
|
if (!this_request) {
|
|
do_hd=NULL;
|
|
return;
|
|
}
|
|
if (this_request->cmd == WIN_WRITE) {
|
|
hd_out(this_request->hd,this_request->nsector,this_request->
|
|
sector,this_request->head,this_request->cyl,
|
|
this_request->cmd,&write_intr);
|
|
for(i=0 ; i<3000 && !(r=inb_p(HD_STATUS)&DRQ_STAT) ; i++)
|
|
/* nothing */ ;
|
|
if (!r) {
|
|
reset_hd(this_request->hd);
|
|
return;
|
|
}
|
|
port_write(HD_DATA,this_request->bh->b_data+
|
|
512*(this_request->nsector&1),256);
|
|
} else if (this_request->cmd == WIN_READ) {
|
|
hd_out(this_request->hd,this_request->nsector,this_request->
|
|
sector,this_request->head,this_request->cyl,
|
|
this_request->cmd,&read_intr);
|
|
} else
|
|
panic("unknown hd-command");
|
|
}
|
|
|
|
/*
|
|
* add-request adds a request to the linked list.
|
|
* It sets the 'sorting'-variable when doing something
|
|
* that interrupts shouldn't touch.
|
|
*/
|
|
static void add_request(struct hd_request * req)
|
|
{
|
|
struct hd_request * tmp;
|
|
|
|
if (req->nsector != 2)
|
|
panic("nsector!=2 not implemented");
|
|
/*
|
|
* Not to mess up the linked lists, we never touch the two first
|
|
* entries (not this_request, as it is used by current interrups,
|
|
* and not this_request->next, as it can be assigned to this_request).
|
|
* This is not too high a price to pay for the ability of not
|
|
* disabling interrupts.
|
|
*/
|
|
sorting=1;
|
|
if (!(tmp=this_request))
|
|
this_request=req;
|
|
else {
|
|
if (!(tmp->next))
|
|
tmp->next=req;
|
|
else {
|
|
tmp=tmp->next;
|
|
for ( ; tmp->next ; tmp=tmp->next)
|
|
if ((IN_ORDER(tmp,req) ||
|
|
!IN_ORDER(tmp,tmp->next)) &&
|
|
IN_ORDER(req,tmp->next))
|
|
break;
|
|
req->next=tmp->next;
|
|
tmp->next=req;
|
|
}
|
|
}
|
|
sorting=0;
|
|
/*
|
|
* NOTE! As a result of sorting, the interrupts may have died down,
|
|
* as they aren't redone due to locking with sorting=1. They might
|
|
* also never have started, if this is the first request in the queue,
|
|
* so we restart them if necessary.
|
|
*/
|
|
if (!do_hd)
|
|
do_request();
|
|
}
|
|
|
|
void rw_abs_hd(int rw,unsigned int nr,unsigned int sec,unsigned int head,
|
|
unsigned int cyl,struct buffer_head * bh)
|
|
{
|
|
struct hd_request * req;
|
|
|
|
if (rw!=READ && rw!=WRITE)
|
|
panic("Bad hd command, must be R/W");
|
|
lock_buffer(bh);
|
|
repeat:
|
|
for (req=0+request ; req<NR_REQUEST+request ; req++)
|
|
if (req->hd<0)
|
|
break;
|
|
if (req==NR_REQUEST+request) {
|
|
sleep_on(&wait_for_request);
|
|
goto repeat;
|
|
}
|
|
req->hd=nr;
|
|
req->nsector=2;
|
|
req->sector=sec;
|
|
req->head=head;
|
|
req->cyl=cyl;
|
|
req->cmd = ((rw==READ)?WIN_READ:WIN_WRITE);
|
|
req->bh=bh;
|
|
req->errors=0;
|
|
req->next=NULL;
|
|
add_request(req);
|
|
wait_on_buffer(bh);
|
|
}
|
|
|
|
void hd_init(void)
|
|
{
|
|
int i;
|
|
|
|
for (i=0 ; i<NR_REQUEST ; i++) {
|
|
request[i].hd = -1;
|
|
request[i].next = NULL;
|
|
}
|
|
for (i=0 ; i<NR_HD ; i++) {
|
|
hd[i*5].start_sect = 0;
|
|
hd[i*5].nr_sects = hd_info[i].head*
|
|
hd_info[i].sect*hd_info[i].cyl;
|
|
}
|
|
set_trap_gate(0x2E,&hd_interrupt);
|
|
outb_p(inb_p(0x21)&0xfb,0x21);
|
|
outb(inb_p(0xA1)&0xbf,0xA1);
|
|
}
|