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linux/drivers/block/swim_iop.c
David Howells 7d12e780e0 IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 15:10:12 +01:00

579 lines
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/*
* Driver for the SWIM (Super Woz Integrated Machine) IOP
* floppy controller on the Macintosh IIfx and Quadra 900/950
*
* Written by Joshua M. Thompson (funaho@jurai.org)
* based on the SWIM3 driver (c) 1996 by Paul Mackerras.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* 1999-06-12 (jmt) - Initial implementation.
*/
/*
* -------------------
* Theory of Operation
* -------------------
*
* Since the SWIM IOP is message-driven we implement a simple request queue
* system. One outstanding request may be queued at any given time (this is
* an IOP limitation); only when that request has completed can a new request
* be sent.
*/
#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/timer.h>
#include <linux/delay.h>
#include <linux/fd.h>
#include <linux/ioctl.h>
#include <linux/blkdev.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/mac_iop.h>
#include <asm/swim_iop.h>
#define DRIVER_VERSION "Version 0.1 (1999-06-12)"
#define MAX_FLOPPIES 4
enum swim_state {
idle,
available,
revalidating,
transferring,
ejecting
};
struct floppy_state {
enum swim_state state;
int drive_num; /* device number */
int secpercyl; /* disk geometry information */
int secpertrack;
int total_secs;
int write_prot; /* 1 if write-protected, 0 if not, -1 dunno */
int ref_count;
struct timer_list timeout;
int ejected;
struct wait_queue *wait;
int wanted;
int timeout_pending;
};
struct swim_iop_req {
int sent;
int complete;
__u8 command[32];
struct floppy_state *fs;
void (*done)(struct swim_iop_req *);
};
static struct swim_iop_req *current_req;
static int floppy_count;
static struct floppy_state floppy_states[MAX_FLOPPIES];
static DEFINE_SPINLOCK(swim_iop_lock);
#define CURRENT elv_next_request(swim_queue)
static char *drive_names[7] = {
"not installed", /* DRV_NONE */
"unknown (1)", /* DRV_UNKNOWN */
"a 400K drive", /* DRV_400K */
"an 800K drive" /* DRV_800K */
"unknown (4)", /* ???? */
"an FDHD", /* DRV_FDHD */
"unknown (6)", /* ???? */
"an Apple HD20" /* DRV_HD20 */
};
int swimiop_init(void);
static void swimiop_init_request(struct swim_iop_req *);
static int swimiop_send_request(struct swim_iop_req *);
static void swimiop_receive(struct iop_msg *);
static void swimiop_status_update(int, struct swim_drvstatus *);
static int swimiop_eject(struct floppy_state *fs);
static int floppy_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long param);
static int floppy_open(struct inode *inode, struct file *filp);
static int floppy_release(struct inode *inode, struct file *filp);
static int floppy_check_change(struct gendisk *disk);
static int floppy_revalidate(struct gendisk *disk);
static int grab_drive(struct floppy_state *fs, enum swim_state state,
int interruptible);
static void release_drive(struct floppy_state *fs);
static void set_timeout(struct floppy_state *fs, int nticks,
void (*proc)(unsigned long));
static void fd_request_timeout(unsigned long);
static void do_fd_request(request_queue_t * q);
static void start_request(struct floppy_state *fs);
static struct block_device_operations floppy_fops = {
.open = floppy_open,
.release = floppy_release,
.ioctl = floppy_ioctl,
.media_changed = floppy_check_change,
.revalidate_disk= floppy_revalidate,
};
static struct request_queue *swim_queue;
/*
* SWIM IOP initialization
*/
int swimiop_init(void)
{
volatile struct swim_iop_req req;
struct swimcmd_status *cmd = (struct swimcmd_status *) &req.command[0];
struct swim_drvstatus *ds = &cmd->status;
struct floppy_state *fs;
int i;
current_req = NULL;
floppy_count = 0;
if (!iop_ism_present)
return -ENODEV;
if (register_blkdev(FLOPPY_MAJOR, "fd"))
return -EBUSY;
swim_queue = blk_init_queue(do_fd_request, &swim_iop_lock);
if (!swim_queue) {
unregister_blkdev(FLOPPY_MAJOR, "fd");
return -ENOMEM;
}
printk("SWIM-IOP: %s by Joshua M. Thompson (funaho@jurai.org)\n",
DRIVER_VERSION);
if (iop_listen(SWIM_IOP, SWIM_CHAN, swimiop_receive, "SWIM") != 0) {
printk(KERN_ERR "SWIM-IOP: IOP channel already in use; can't initialize.\n");
unregister_blkdev(FLOPPY_MAJOR, "fd");
blk_cleanup_queue(swim_queue);
return -EBUSY;
}
printk(KERN_ERR "SWIM_IOP: probing for installed drives.\n");
for (i = 0 ; i < MAX_FLOPPIES ; i++) {
memset(&floppy_states[i], 0, sizeof(struct floppy_state));
fs = &floppy_states[floppy_count];
swimiop_init_request(&req);
cmd->code = CMD_STATUS;
cmd->drive_num = i + 1;
if (swimiop_send_request(&req) != 0) continue;
while (!req.complete);
if (cmd->error != 0) {
printk(KERN_ERR "SWIM-IOP: probe on drive %d returned error %d\n", i, (uint) cmd->error);
continue;
}
if (ds->installed != 0x01) continue;
printk("SWIM-IOP: drive %d is %s (%s, %s, %s, %s)\n", i,
drive_names[ds->info.type],
ds->info.external? "ext" : "int",
ds->info.scsi? "scsi" : "floppy",
ds->info.fixed? "fixed" : "removable",
ds->info.secondary? "secondary" : "primary");
swimiop_status_update(floppy_count, ds);
fs->state = idle;
init_timer(&fs->timeout);
floppy_count++;
}
printk("SWIM-IOP: detected %d installed drives.\n", floppy_count);
for (i = 0; i < floppy_count; i++) {
struct gendisk *disk = alloc_disk(1);
if (!disk)
continue;
disk->major = FLOPPY_MAJOR;
disk->first_minor = i;
disk->fops = &floppy_fops;
sprintf(disk->disk_name, "fd%d", i);
disk->private_data = &floppy_states[i];
disk->queue = swim_queue;
set_capacity(disk, 2880 * 2);
add_disk(disk);
}
return 0;
}
static void swimiop_init_request(struct swim_iop_req *req)
{
req->sent = 0;
req->complete = 0;
req->done = NULL;
}
static int swimiop_send_request(struct swim_iop_req *req)
{
unsigned long flags;
int err;
/* It's doubtful an interrupt routine would try to send */
/* a SWIM request, but I'd rather play it safe here. */
local_irq_save(flags);
if (current_req != NULL) {
local_irq_restore(flags);
return -ENOMEM;
}
current_req = req;
/* Interrupts should be back on for iop_send_message() */
local_irq_restore(flags);
err = iop_send_message(SWIM_IOP, SWIM_CHAN, (void *) req,
sizeof(req->command), (__u8 *) &req->command[0],
swimiop_receive);
/* No race condition here; we own current_req at this point */
if (err) {
current_req = NULL;
} else {
req->sent = 1;
}
return err;
}
/*
* Receive a SWIM message from the IOP.
*
* This will be called in two cases:
*
* 1. A message has been successfully sent to the IOP.
* 2. An unsolicited message was received from the IOP.
*/
void swimiop_receive(struct iop_msg *msg)
{
struct swim_iop_req *req;
struct swimmsg_status *sm;
struct swim_drvstatus *ds;
req = current_req;
switch(msg->status) {
case IOP_MSGSTATUS_COMPLETE:
memcpy(&req->command[0], &msg->reply[0], sizeof(req->command));
req->complete = 1;
if (req->done) (*req->done)(req);
current_req = NULL;
break;
case IOP_MSGSTATUS_UNSOL:
sm = (struct swimmsg_status *) &msg->message[0];
ds = &sm->status;
swimiop_status_update(sm->drive_num, ds);
iop_complete_message(msg);
break;
}
}
static void swimiop_status_update(int drive_num, struct swim_drvstatus *ds)
{
struct floppy_state *fs = &floppy_states[drive_num];
fs->write_prot = (ds->write_prot == 0x80);
if ((ds->disk_in_drive != 0x01) && (ds->disk_in_drive != 0x02)) {
fs->ejected = 1;
} else {
fs->ejected = 0;
}
switch(ds->info.type) {
case DRV_400K:
fs->secpercyl = 10;
fs->secpertrack = 10;
fs->total_secs = 800;
break;
case DRV_800K:
fs->secpercyl = 20;
fs->secpertrack = 10;
fs->total_secs = 1600;
break;
case DRV_FDHD:
fs->secpercyl = 36;
fs->secpertrack = 18;
fs->total_secs = 2880;
break;
default:
fs->secpercyl = 0;
fs->secpertrack = 0;
fs->total_secs = 0;
break;
}
}
static int swimiop_eject(struct floppy_state *fs)
{
int err, n;
struct swim_iop_req req;
struct swimcmd_eject *cmd = (struct swimcmd_eject *) &req.command[0];
err = grab_drive(fs, ejecting, 1);
if (err) return err;
swimiop_init_request(&req);
cmd->code = CMD_EJECT;
cmd->drive_num = fs->drive_num;
err = swimiop_send_request(&req);
if (err) {
release_drive(fs);
return err;
}
for (n = 2*HZ; n > 0; --n) {
if (req.complete) break;
if (signal_pending(current)) {
err = -EINTR;
break;
}
schedule_timeout_interruptible(1);
}
release_drive(fs);
return cmd->error;
}
static struct floppy_struct floppy_type =
{ 2880,18,2,80,0,0x1B,0x00,0xCF,0x6C,NULL }; /* 7 1.44MB 3.5" */
static int floppy_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long param)
{
struct floppy_state *fs = inode->i_bdev->bd_disk->private_data;
int err;
if ((cmd & 0x80) && !capable(CAP_SYS_ADMIN))
return -EPERM;
switch (cmd) {
case FDEJECT:
if (fs->ref_count != 1)
return -EBUSY;
err = swimiop_eject(fs);
return err;
case FDGETPRM:
if (copy_to_user((void *) param, (void *) &floppy_type,
sizeof(struct floppy_struct)))
return -EFAULT;
return 0;
}
return -ENOTTY;
}
static int floppy_open(struct inode *inode, struct file *filp)
{
struct floppy_state *fs = inode->i_bdev->bd_disk->private_data;
if (fs->ref_count == -1 || filp->f_flags & O_EXCL)
return -EBUSY;
if ((filp->f_flags & O_NDELAY) == 0 && (filp->f_mode & 3)) {
check_disk_change(inode->i_bdev);
if (fs->ejected)
return -ENXIO;
}
if ((filp->f_mode & 2) && fs->write_prot)
return -EROFS;
if (filp->f_flags & O_EXCL)
fs->ref_count = -1;
else
++fs->ref_count;
return 0;
}
static int floppy_release(struct inode *inode, struct file *filp)
{
struct floppy_state *fs = inode->i_bdev->bd_disk->private_data;
if (fs->ref_count > 0)
fs->ref_count--;
return 0;
}
static int floppy_check_change(struct gendisk *disk)
{
struct floppy_state *fs = disk->private_data;
return fs->ejected;
}
static int floppy_revalidate(struct gendisk *disk)
{
struct floppy_state *fs = disk->private_data;
grab_drive(fs, revalidating, 0);
/* yadda, yadda */
release_drive(fs);
return 0;
}
static void floppy_off(unsigned int nr)
{
}
static int grab_drive(struct floppy_state *fs, enum swim_state state,
int interruptible)
{
unsigned long flags;
local_irq_save(flags);
if (fs->state != idle) {
++fs->wanted;
while (fs->state != available) {
if (interruptible && signal_pending(current)) {
--fs->wanted;
local_irq_restore(flags);
return -EINTR;
}
interruptible_sleep_on(&fs->wait);
}
--fs->wanted;
}
fs->state = state;
local_irq_restore(flags);
return 0;
}
static void release_drive(struct floppy_state *fs)
{
unsigned long flags;
local_irq_save(flags);
fs->state = idle;
start_request(fs);
local_irq_restore(flags);
}
static void set_timeout(struct floppy_state *fs, int nticks,
void (*proc)(unsigned long))
{
unsigned long flags;
local_irq_save(flags);
if (fs->timeout_pending)
del_timer(&fs->timeout);
init_timer(&fs->timeout);
fs->timeout.expires = jiffies + nticks;
fs->timeout.function = proc;
fs->timeout.data = (unsigned long) fs;
add_timer(&fs->timeout);
fs->timeout_pending = 1;
local_irq_restore(flags);
}
static void do_fd_request(request_queue_t * q)
{
int i;
for (i = 0 ; i < floppy_count ; i++) {
start_request(&floppy_states[i]);
}
}
static void fd_request_complete(struct swim_iop_req *req)
{
struct floppy_state *fs = req->fs;
struct swimcmd_rw *cmd = (struct swimcmd_rw *) &req->command[0];
del_timer(&fs->timeout);
fs->timeout_pending = 0;
fs->state = idle;
if (cmd->error) {
printk(KERN_ERR "SWIM-IOP: error %d on read/write request.\n", cmd->error);
end_request(CURRENT, 0);
} else {
CURRENT->sector += cmd->num_blocks;
CURRENT->current_nr_sectors -= cmd->num_blocks;
if (CURRENT->current_nr_sectors <= 0) {
end_request(CURRENT, 1);
return;
}
}
start_request(fs);
}
static void fd_request_timeout(unsigned long data)
{
struct floppy_state *fs = (struct floppy_state *) data;
fs->timeout_pending = 0;
end_request(CURRENT, 0);
fs->state = idle;
}
static void start_request(struct floppy_state *fs)
{
volatile struct swim_iop_req req;
struct swimcmd_rw *cmd = (struct swimcmd_rw *) &req.command[0];
if (fs->state == idle && fs->wanted) {
fs->state = available;
wake_up(&fs->wait);
return;
}
while (CURRENT && fs->state == idle) {
if (CURRENT->bh && !buffer_locked(CURRENT->bh))
panic("floppy: block not locked");
#if 0
printk("do_fd_req: dev=%s cmd=%d sec=%ld nr_sec=%ld buf=%p\n",
CURRENT->rq_disk->disk_name, CURRENT->cmd,
CURRENT->sector, CURRENT->nr_sectors, CURRENT->buffer);
printk(" errors=%d current_nr_sectors=%ld\n",
CURRENT->errors, CURRENT->current_nr_sectors);
#endif
if (CURRENT->sector < 0 || CURRENT->sector >= fs->total_secs) {
end_request(CURRENT, 0);
continue;
}
if (CURRENT->current_nr_sectors == 0) {
end_request(CURRENT, 1);
continue;
}
if (fs->ejected) {
end_request(CURRENT, 0);
continue;
}
swimiop_init_request(&req);
req.fs = fs;
req.done = fd_request_complete;
if (CURRENT->cmd == WRITE) {
if (fs->write_prot) {
end_request(CURRENT, 0);
continue;
}
cmd->code = CMD_WRITE;
} else {
cmd->code = CMD_READ;
}
cmd->drive_num = fs->drive_num;
cmd->buffer = CURRENT->buffer;
cmd->first_block = CURRENT->sector;
cmd->num_blocks = CURRENT->current_nr_sectors;
if (swimiop_send_request(&req)) {
end_request(CURRENT, 0);
continue;
}
set_timeout(fs, HZ*CURRENT->current_nr_sectors,
fd_request_timeout);
fs->state = transferring;
}
}
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