kernel-ark/drivers/block/hd.c
Tejun Heo 0191944282 hd: fix locking
hd dance around local irq and HD_IRQ enable without achieving much.
It ends up transferring data from irq handler with both local irq and
HD_IRQ disabled.  The only place it actually does something is while
transferring the first block of a request which it does with HD_IRQ
disabled but local irq enabled.

Unfortunately, the dancing is horribly broken from locking POV.  IRQ
and timeout handlers access block queue without grabbing the queue
lock and running the driver in SMP configuration crashes the whole
machine pretty quickly.

Remove meaningless irq enable/disable dancing and add proper locking
in issue, irq and timeout paths.

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 20:24:20 +02:00

815 lines
19 KiB
C

/*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* This is the low-level hd interrupt support. It traverses the
* request-list, using interrupts to jump between functions. As
* all the functions are called within interrupts, we may not
* sleep. Special care is recommended.
*
* modified by Drew Eckhardt to check nr of hd's from the CMOS.
*
* Thanks to Branko Lankester, lankeste@fwi.uva.nl, who found a bug
* in the early extended-partition checks and added DM partitions
*
* IRQ-unmask, drive-id, multiple-mode, support for ">16 heads",
* and general streamlining by Mark Lord.
*
* Removed 99% of above. Use Mark's ide driver for those options.
* This is now a lightweight ST-506 driver. (Paul Gortmaker)
*
* Modified 1995 Russell King for ARM processor.
*
* Bugfix: max_sectors must be <= 255 or the wheels tend to come
* off in a hurry once you queue things up - Paul G. 02/2001
*/
/* Uncomment the following if you want verbose error reports. */
/* #define VERBOSE_ERRORS */
#include <linux/blkdev.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/interrupt.h>
#include <linux/timer.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/genhd.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/blkpg.h>
#include <linux/ata.h>
#include <linux/hdreg.h>
#define HD_IRQ 14
#define REALLY_SLOW_IO
#include <asm/system.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#ifdef __arm__
#undef HD_IRQ
#endif
#include <asm/irq.h>
#ifdef __arm__
#define HD_IRQ IRQ_HARDDISK
#endif
/* Hd controller regster ports */
#define HD_DATA 0x1f0 /* _CTL when writing */
#define HD_ERROR 0x1f1 /* see err-bits */
#define HD_NSECTOR 0x1f2 /* nr of sectors to read/write */
#define HD_SECTOR 0x1f3 /* starting sector */
#define HD_LCYL 0x1f4 /* starting cylinder */
#define HD_HCYL 0x1f5 /* high byte of starting cyl */
#define HD_CURRENT 0x1f6 /* 101dhhhh , d=drive, hhhh=head */
#define HD_STATUS 0x1f7 /* see status-bits */
#define HD_FEATURE HD_ERROR /* same io address, read=error, write=feature */
#define HD_PRECOMP HD_FEATURE /* obsolete use of this port - predates IDE */
#define HD_COMMAND HD_STATUS /* same io address, read=status, write=cmd */
#define HD_CMD 0x3f6 /* used for resets */
#define HD_ALTSTATUS 0x3f6 /* same as HD_STATUS but doesn't clear irq */
/* Bits of HD_STATUS */
#define ERR_STAT 0x01
#define INDEX_STAT 0x02
#define ECC_STAT 0x04 /* Corrected error */
#define DRQ_STAT 0x08
#define SEEK_STAT 0x10
#define SERVICE_STAT SEEK_STAT
#define WRERR_STAT 0x20
#define READY_STAT 0x40
#define BUSY_STAT 0x80
/* Bits for HD_ERROR */
#define MARK_ERR 0x01 /* Bad address mark */
#define TRK0_ERR 0x02 /* couldn't find track 0 */
#define ABRT_ERR 0x04 /* Command aborted */
#define MCR_ERR 0x08 /* media change request */
#define ID_ERR 0x10 /* ID field not found */
#define MC_ERR 0x20 /* media changed */
#define ECC_ERR 0x40 /* Uncorrectable ECC error */
#define BBD_ERR 0x80 /* pre-EIDE meaning: block marked bad */
#define ICRC_ERR 0x80 /* new meaning: CRC error during transfer */
static DEFINE_SPINLOCK(hd_lock);
static struct request_queue *hd_queue;
#define MAJOR_NR HD_MAJOR
#define QUEUE (hd_queue)
#define CURRENT elv_next_request(hd_queue)
#define TIMEOUT_VALUE (6*HZ)
#define HD_DELAY 0
#define MAX_ERRORS 16 /* Max read/write errors/sector */
#define RESET_FREQ 8 /* Reset controller every 8th retry */
#define RECAL_FREQ 4 /* Recalibrate every 4th retry */
#define MAX_HD 2
#define STAT_OK (READY_STAT|SEEK_STAT)
#define OK_STATUS(s) (((s)&(STAT_OK|(BUSY_STAT|WRERR_STAT|ERR_STAT)))==STAT_OK)
static void recal_intr(void);
static void bad_rw_intr(void);
static int reset;
static int hd_error;
/*
* This struct defines the HD's and their types.
*/
struct hd_i_struct {
unsigned int head, sect, cyl, wpcom, lzone, ctl;
int unit;
int recalibrate;
int special_op;
};
#ifdef HD_TYPE
static struct hd_i_struct hd_info[] = { HD_TYPE };
static int NR_HD = ARRAY_SIZE(hd_info);
#else
static struct hd_i_struct hd_info[MAX_HD];
static int NR_HD;
#endif
static struct gendisk *hd_gendisk[MAX_HD];
static struct timer_list device_timer;
#define TIMEOUT_VALUE (6*HZ)
#define SET_TIMER \
do { \
mod_timer(&device_timer, jiffies + TIMEOUT_VALUE); \
} while (0)
static void (*do_hd)(void) = NULL;
#define SET_HANDLER(x) \
if ((do_hd = (x)) != NULL) \
SET_TIMER; \
else \
del_timer(&device_timer);
#if (HD_DELAY > 0)
#include <asm/i8253.h>
unsigned long last_req;
unsigned long read_timer(void)
{
unsigned long t, flags;
int i;
spin_lock_irqsave(&i8253_lock, flags);
t = jiffies * 11932;
outb_p(0, 0x43);
i = inb_p(0x40);
i |= inb(0x40) << 8;
spin_unlock_irqrestore(&i8253_lock, flags);
return(t - i);
}
#endif
static void __init hd_setup(char *str, int *ints)
{
int hdind = 0;
if (ints[0] != 3)
return;
if (hd_info[0].head != 0)
hdind = 1;
hd_info[hdind].head = ints[2];
hd_info[hdind].sect = ints[3];
hd_info[hdind].cyl = ints[1];
hd_info[hdind].wpcom = 0;
hd_info[hdind].lzone = ints[1];
hd_info[hdind].ctl = (ints[2] > 8 ? 8 : 0);
NR_HD = hdind+1;
}
static void dump_status(const char *msg, unsigned int stat)
{
char *name = "hd?";
if (CURRENT)
name = CURRENT->rq_disk->disk_name;
#ifdef VERBOSE_ERRORS
printk("%s: %s: status=0x%02x { ", name, msg, stat & 0xff);
if (stat & BUSY_STAT) printk("Busy ");
if (stat & READY_STAT) printk("DriveReady ");
if (stat & WRERR_STAT) printk("WriteFault ");
if (stat & SEEK_STAT) printk("SeekComplete ");
if (stat & DRQ_STAT) printk("DataRequest ");
if (stat & ECC_STAT) printk("CorrectedError ");
if (stat & INDEX_STAT) printk("Index ");
if (stat & ERR_STAT) printk("Error ");
printk("}\n");
if ((stat & ERR_STAT) == 0) {
hd_error = 0;
} else {
hd_error = inb(HD_ERROR);
printk("%s: %s: error=0x%02x { ", name, msg, hd_error & 0xff);
if (hd_error & BBD_ERR) printk("BadSector ");
if (hd_error & ECC_ERR) printk("UncorrectableError ");
if (hd_error & ID_ERR) printk("SectorIdNotFound ");
if (hd_error & ABRT_ERR) printk("DriveStatusError ");
if (hd_error & TRK0_ERR) printk("TrackZeroNotFound ");
if (hd_error & MARK_ERR) printk("AddrMarkNotFound ");
printk("}");
if (hd_error & (BBD_ERR|ECC_ERR|ID_ERR|MARK_ERR)) {
printk(", CHS=%d/%d/%d", (inb(HD_HCYL)<<8) + inb(HD_LCYL),
inb(HD_CURRENT) & 0xf, inb(HD_SECTOR));
if (CURRENT)
printk(", sector=%ld", CURRENT->sector);
}
printk("\n");
}
#else
printk("%s: %s: status=0x%02x.\n", name, msg, stat & 0xff);
if ((stat & ERR_STAT) == 0) {
hd_error = 0;
} else {
hd_error = inb(HD_ERROR);
printk("%s: %s: error=0x%02x.\n", name, msg, hd_error & 0xff);
}
#endif
}
static void check_status(void)
{
int i = inb_p(HD_STATUS);
if (!OK_STATUS(i)) {
dump_status("check_status", i);
bad_rw_intr();
}
}
static int controller_busy(void)
{
int retries = 100000;
unsigned char status;
do {
status = inb_p(HD_STATUS);
} while ((status & BUSY_STAT) && --retries);
return status;
}
static int status_ok(void)
{
unsigned char status = inb_p(HD_STATUS);
if (status & BUSY_STAT)
return 1; /* Ancient, but does it make sense??? */
if (status & WRERR_STAT)
return 0;
if (!(status & READY_STAT))
return 0;
if (!(status & SEEK_STAT))
return 0;
return 1;
}
static int controller_ready(unsigned int drive, unsigned int head)
{
int retry = 100;
do {
if (controller_busy() & BUSY_STAT)
return 0;
outb_p(0xA0 | (drive<<4) | head, HD_CURRENT);
if (status_ok())
return 1;
} while (--retry);
return 0;
}
static void hd_out(struct hd_i_struct *disk,
unsigned int nsect,
unsigned int sect,
unsigned int head,
unsigned int cyl,
unsigned int cmd,
void (*intr_addr)(void))
{
unsigned short port;
#if (HD_DELAY > 0)
while (read_timer() - last_req < HD_DELAY)
/* nothing */;
#endif
if (reset)
return;
if (!controller_ready(disk->unit, head)) {
reset = 1;
return;
}
SET_HANDLER(intr_addr);
outb_p(disk->ctl, HD_CMD);
port = HD_DATA;
outb_p(disk->wpcom >> 2, ++port);
outb_p(nsect, ++port);
outb_p(sect, ++port);
outb_p(cyl, ++port);
outb_p(cyl >> 8, ++port);
outb_p(0xA0 | (disk->unit << 4) | head, ++port);
outb_p(cmd, ++port);
}
static void hd_request (void);
static int drive_busy(void)
{
unsigned int i;
unsigned char c;
for (i = 0; i < 500000 ; i++) {
c = inb_p(HD_STATUS);
if ((c & (BUSY_STAT | READY_STAT | SEEK_STAT)) == STAT_OK)
return 0;
}
dump_status("reset timed out", c);
return 1;
}
static void reset_controller(void)
{
int i;
outb_p(4, HD_CMD);
for (i = 0; i < 1000; i++) barrier();
outb_p(hd_info[0].ctl & 0x0f, HD_CMD);
for (i = 0; i < 1000; i++) barrier();
if (drive_busy())
printk("hd: controller still busy\n");
else if ((hd_error = inb(HD_ERROR)) != 1)
printk("hd: controller reset failed: %02x\n", hd_error);
}
static void reset_hd(void)
{
static int i;
repeat:
if (reset) {
reset = 0;
i = -1;
reset_controller();
} else {
check_status();
if (reset)
goto repeat;
}
if (++i < NR_HD) {
struct hd_i_struct *disk = &hd_info[i];
disk->special_op = disk->recalibrate = 1;
hd_out(disk, disk->sect, disk->sect, disk->head-1,
disk->cyl, ATA_CMD_INIT_DEV_PARAMS, &reset_hd);
if (reset)
goto repeat;
} else
hd_request();
}
/*
* Ok, don't know what to do with the unexpected interrupts: on some machines
* doing a reset and a retry seems to result in an eternal loop. Right now I
* ignore it, and just set the timeout.
*
* On laptops (and "green" PCs), an unexpected interrupt occurs whenever the
* drive enters "idle", "standby", or "sleep" mode, so if the status looks
* "good", we just ignore the interrupt completely.
*/
static void unexpected_hd_interrupt(void)
{
unsigned int stat = inb_p(HD_STATUS);
if (stat & (BUSY_STAT|DRQ_STAT|ECC_STAT|ERR_STAT)) {
dump_status("unexpected interrupt", stat);
SET_TIMER;
}
}
/*
* bad_rw_intr() now tries to be a bit smarter and does things
* according to the error returned by the controller.
* -Mika Liljeberg (liljeber@cs.Helsinki.FI)
*/
static void bad_rw_intr(void)
{
struct request *req = CURRENT;
if (req != NULL) {
struct hd_i_struct *disk = req->rq_disk->private_data;
if (++req->errors >= MAX_ERRORS || (hd_error & BBD_ERR)) {
end_request(req, 0);
disk->special_op = disk->recalibrate = 1;
} else if (req->errors % RESET_FREQ == 0)
reset = 1;
else if ((hd_error & TRK0_ERR) || req->errors % RECAL_FREQ == 0)
disk->special_op = disk->recalibrate = 1;
/* Otherwise just retry */
}
}
static inline int wait_DRQ(void)
{
int retries;
int stat;
for (retries = 0; retries < 100000; retries++) {
stat = inb_p(HD_STATUS);
if (stat & DRQ_STAT)
return 0;
}
dump_status("wait_DRQ", stat);
return -1;
}
static void read_intr(void)
{
struct request *req;
int i, retries = 100000;
do {
i = (unsigned) inb_p(HD_STATUS);
if (i & BUSY_STAT)
continue;
if (!OK_STATUS(i))
break;
if (i & DRQ_STAT)
goto ok_to_read;
} while (--retries > 0);
dump_status("read_intr", i);
bad_rw_intr();
hd_request();
return;
ok_to_read:
req = CURRENT;
insw(HD_DATA, req->buffer, 256);
req->sector++;
req->buffer += 512;
req->errors = 0;
i = --req->nr_sectors;
--req->current_nr_sectors;
#ifdef DEBUG
printk("%s: read: sector %ld, remaining = %ld, buffer=%p\n",
req->rq_disk->disk_name, req->sector, req->nr_sectors,
req->buffer+512);
#endif
if (req->current_nr_sectors <= 0)
end_request(req, 1);
if (i > 0) {
SET_HANDLER(&read_intr);
return;
}
(void) inb_p(HD_STATUS);
#if (HD_DELAY > 0)
last_req = read_timer();
#endif
if (elv_next_request(QUEUE))
hd_request();
return;
}
static void write_intr(void)
{
struct request *req = CURRENT;
int i;
int retries = 100000;
do {
i = (unsigned) inb_p(HD_STATUS);
if (i & BUSY_STAT)
continue;
if (!OK_STATUS(i))
break;
if ((req->nr_sectors <= 1) || (i & DRQ_STAT))
goto ok_to_write;
} while (--retries > 0);
dump_status("write_intr", i);
bad_rw_intr();
hd_request();
return;
ok_to_write:
req->sector++;
i = --req->nr_sectors;
--req->current_nr_sectors;
req->buffer += 512;
if (!i || (req->bio && req->current_nr_sectors <= 0))
end_request(req, 1);
if (i > 0) {
SET_HANDLER(&write_intr);
outsw(HD_DATA, req->buffer, 256);
} else {
#if (HD_DELAY > 0)
last_req = read_timer();
#endif
hd_request();
}
return;
}
static void recal_intr(void)
{
check_status();
#if (HD_DELAY > 0)
last_req = read_timer();
#endif
hd_request();
}
/*
* This is another of the error-routines I don't know what to do with. The
* best idea seems to just set reset, and start all over again.
*/
static void hd_times_out(unsigned long dummy)
{
char *name;
do_hd = NULL;
if (!CURRENT)
return;
spin_lock_irq(hd_queue->queue_lock);
reset = 1;
name = CURRENT->rq_disk->disk_name;
printk("%s: timeout\n", name);
if (++CURRENT->errors >= MAX_ERRORS) {
#ifdef DEBUG
printk("%s: too many errors\n", name);
#endif
end_request(CURRENT, 0);
}
hd_request();
spin_unlock_irq(hd_queue->queue_lock);
}
static int do_special_op(struct hd_i_struct *disk, struct request *req)
{
if (disk->recalibrate) {
disk->recalibrate = 0;
hd_out(disk, disk->sect, 0, 0, 0, ATA_CMD_RESTORE, &recal_intr);
return reset;
}
if (disk->head > 16) {
printk("%s: cannot handle device with more than 16 heads - giving up\n", req->rq_disk->disk_name);
end_request(req, 0);
}
disk->special_op = 0;
return 1;
}
/*
* The driver enables interrupts as much as possible. In order to do this,
* (a) the device-interrupt is disabled before entering hd_request(),
* and (b) the timeout-interrupt is disabled before the sti().
*
* Interrupts are still masked (by default) whenever we are exchanging
* data/cmds with a drive, because some drives seem to have very poor
* tolerance for latency during I/O. The IDE driver has support to unmask
* interrupts for non-broken hardware, so use that driver if required.
*/
static void hd_request(void)
{
unsigned int block, nsect, sec, track, head, cyl;
struct hd_i_struct *disk;
struct request *req;
if (do_hd)
return;
repeat:
del_timer(&device_timer);
req = CURRENT;
if (!req) {
do_hd = NULL;
return;
}
if (reset) {
reset_hd();
return;
}
disk = req->rq_disk->private_data;
block = req->sector;
nsect = req->nr_sectors;
if (block >= get_capacity(req->rq_disk) ||
((block+nsect) > get_capacity(req->rq_disk))) {
printk("%s: bad access: block=%d, count=%d\n",
req->rq_disk->disk_name, block, nsect);
end_request(req, 0);
goto repeat;
}
if (disk->special_op) {
if (do_special_op(disk, req))
goto repeat;
return;
}
sec = block % disk->sect + 1;
track = block / disk->sect;
head = track % disk->head;
cyl = track / disk->head;
#ifdef DEBUG
printk("%s: %sing: CHS=%d/%d/%d, sectors=%d, buffer=%p\n",
req->rq_disk->disk_name,
req_data_dir(req) == READ ? "read" : "writ",
cyl, head, sec, nsect, req->buffer);
#endif
if (blk_fs_request(req)) {
switch (rq_data_dir(req)) {
case READ:
hd_out(disk, nsect, sec, head, cyl, ATA_CMD_PIO_READ,
&read_intr);
if (reset)
goto repeat;
break;
case WRITE:
hd_out(disk, nsect, sec, head, cyl, ATA_CMD_PIO_WRITE,
&write_intr);
if (reset)
goto repeat;
if (wait_DRQ()) {
bad_rw_intr();
goto repeat;
}
outsw(HD_DATA, req->buffer, 256);
break;
default:
printk("unknown hd-command\n");
end_request(req, 0);
break;
}
}
}
static void do_hd_request(struct request_queue *q)
{
hd_request();
}
static int hd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
struct hd_i_struct *disk = bdev->bd_disk->private_data;
geo->heads = disk->head;
geo->sectors = disk->sect;
geo->cylinders = disk->cyl;
return 0;
}
/*
* Releasing a block device means we sync() it, so that it can safely
* be forgotten about...
*/
static irqreturn_t hd_interrupt(int irq, void *dev_id)
{
void (*handler)(void) = do_hd;
spin_lock(hd_queue->queue_lock);
do_hd = NULL;
del_timer(&device_timer);
if (!handler)
handler = unexpected_hd_interrupt;
handler();
spin_unlock(hd_queue->queue_lock);
return IRQ_HANDLED;
}
static struct block_device_operations hd_fops = {
.getgeo = hd_getgeo,
};
/*
* This is the hard disk IRQ description. The IRQF_DISABLED in sa_flags
* means we run the IRQ-handler with interrupts disabled: this is bad for
* interrupt latency, but anything else has led to problems on some
* machines.
*
* We enable interrupts in some of the routines after making sure it's
* safe.
*/
static int __init hd_init(void)
{
int drive;
if (register_blkdev(MAJOR_NR, "hd"))
return -1;
hd_queue = blk_init_queue(do_hd_request, &hd_lock);
if (!hd_queue) {
unregister_blkdev(MAJOR_NR, "hd");
return -ENOMEM;
}
blk_queue_max_sectors(hd_queue, 255);
init_timer(&device_timer);
device_timer.function = hd_times_out;
blk_queue_hardsect_size(hd_queue, 512);
if (!NR_HD) {
/*
* We don't know anything about the drive. This means
* that you *MUST* specify the drive parameters to the
* kernel yourself.
*
* If we were on an i386, we used to read this info from
* the BIOS or CMOS. This doesn't work all that well,
* since this assumes that this is a primary or secondary
* drive, and if we're using this legacy driver, it's
* probably an auxilliary controller added to recover
* legacy data off an ST-506 drive. Either way, it's
* definitely safest to have the user explicitly specify
* the information.
*/
printk("hd: no drives specified - use hd=cyl,head,sectors"
" on kernel command line\n");
goto out;
}
for (drive = 0 ; drive < NR_HD ; drive++) {
struct gendisk *disk = alloc_disk(64);
struct hd_i_struct *p = &hd_info[drive];
if (!disk)
goto Enomem;
disk->major = MAJOR_NR;
disk->first_minor = drive << 6;
disk->fops = &hd_fops;
sprintf(disk->disk_name, "hd%c", 'a'+drive);
disk->private_data = p;
set_capacity(disk, p->head * p->sect * p->cyl);
disk->queue = hd_queue;
p->unit = drive;
hd_gendisk[drive] = disk;
printk("%s: %luMB, CHS=%d/%d/%d\n",
disk->disk_name, (unsigned long)get_capacity(disk)/2048,
p->cyl, p->head, p->sect);
}
if (request_irq(HD_IRQ, hd_interrupt, IRQF_DISABLED, "hd", NULL)) {
printk("hd: unable to get IRQ%d for the hard disk driver\n",
HD_IRQ);
goto out1;
}
if (!request_region(HD_DATA, 8, "hd")) {
printk(KERN_WARNING "hd: port 0x%x busy\n", HD_DATA);
goto out2;
}
if (!request_region(HD_CMD, 1, "hd(cmd)")) {
printk(KERN_WARNING "hd: port 0x%x busy\n", HD_CMD);
goto out3;
}
/* Let them fly */
for (drive = 0; drive < NR_HD; drive++)
add_disk(hd_gendisk[drive]);
return 0;
out3:
release_region(HD_DATA, 8);
out2:
free_irq(HD_IRQ, NULL);
out1:
for (drive = 0; drive < NR_HD; drive++)
put_disk(hd_gendisk[drive]);
NR_HD = 0;
out:
del_timer(&device_timer);
unregister_blkdev(MAJOR_NR, "hd");
blk_cleanup_queue(hd_queue);
return -1;
Enomem:
while (drive--)
put_disk(hd_gendisk[drive]);
goto out;
}
static int __init parse_hd_setup(char *line)
{
int ints[6];
(void) get_options(line, ARRAY_SIZE(ints), ints);
hd_setup(NULL, ints);
return 1;
}
__setup("hd=", parse_hd_setup);
late_initcall(hd_init);