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linux/drivers/parport/parport_gsc.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

439 lines
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/*
* Low-level parallel-support for PC-style hardware integrated in the
* LASI-Controller (on GSC-Bus) for HP-PARISC Workstations
*
* 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.
*
* (C) 1999-2001 by Helge Deller <deller@gmx.de>
*
*
* based on parport_pc.c by
* Grant Guenther <grant@torque.net>
* Phil Blundell <philb@gnu.org>
* Tim Waugh <tim@cyberelk.demon.co.uk>
* Jose Renau <renau@acm.org>
* David Campbell
* Andrea Arcangeli
*/
#undef DEBUG /* undef for production */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/pci.h>
#include <linux/sysctl.h>
#include <asm/io.h>
#include <asm/dma.h>
#include <asm/uaccess.h>
#include <asm/superio.h>
#include <linux/parport.h>
#include <asm/pdc.h>
#include <asm/parisc-device.h>
#include <asm/hardware.h>
#include "parport_gsc.h"
MODULE_AUTHOR("Helge Deller <deller@gmx.de>");
MODULE_DESCRIPTION("HP-PARISC PC-style parallel port driver");
MODULE_SUPPORTED_DEVICE("integrated PC-style parallel port");
MODULE_LICENSE("GPL");
/*
* Clear TIMEOUT BIT in EPP MODE
*
* This is also used in SPP detection.
*/
static int clear_epp_timeout(struct parport *pb)
{
unsigned char r;
if (!(parport_gsc_read_status(pb) & 0x01))
return 1;
/* To clear timeout some chips require double read */
parport_gsc_read_status(pb);
r = parport_gsc_read_status(pb);
parport_writeb (r | 0x01, STATUS (pb)); /* Some reset by writing 1 */
parport_writeb (r & 0xfe, STATUS (pb)); /* Others by writing 0 */
r = parport_gsc_read_status(pb);
return !(r & 0x01);
}
/*
* Access functions.
*
* Most of these aren't static because they may be used by the
* parport_xxx_yyy macros. extern __inline__ versions of several
* of these are in parport_gsc.h.
*/
static irqreturn_t parport_gsc_interrupt(int irq, void *dev_id)
{
parport_generic_irq(irq, (struct parport *) dev_id);
return IRQ_HANDLED;
}
void parport_gsc_init_state(struct pardevice *dev, struct parport_state *s)
{
s->u.pc.ctr = 0xc | (dev->irq_func ? 0x10 : 0x0);
}
void parport_gsc_save_state(struct parport *p, struct parport_state *s)
{
s->u.pc.ctr = parport_readb (CONTROL (p));
}
void parport_gsc_restore_state(struct parport *p, struct parport_state *s)
{
parport_writeb (s->u.pc.ctr, CONTROL (p));
}
struct parport_operations parport_gsc_ops =
{
.write_data = parport_gsc_write_data,
.read_data = parport_gsc_read_data,
.write_control = parport_gsc_write_control,
.read_control = parport_gsc_read_control,
.frob_control = parport_gsc_frob_control,
.read_status = parport_gsc_read_status,
.enable_irq = parport_gsc_enable_irq,
.disable_irq = parport_gsc_disable_irq,
.data_forward = parport_gsc_data_forward,
.data_reverse = parport_gsc_data_reverse,
.init_state = parport_gsc_init_state,
.save_state = parport_gsc_save_state,
.restore_state = parport_gsc_restore_state,
.epp_write_data = parport_ieee1284_epp_write_data,
.epp_read_data = parport_ieee1284_epp_read_data,
.epp_write_addr = parport_ieee1284_epp_write_addr,
.epp_read_addr = parport_ieee1284_epp_read_addr,
.ecp_write_data = parport_ieee1284_ecp_write_data,
.ecp_read_data = parport_ieee1284_ecp_read_data,
.ecp_write_addr = parport_ieee1284_ecp_write_addr,
.compat_write_data = parport_ieee1284_write_compat,
.nibble_read_data = parport_ieee1284_read_nibble,
.byte_read_data = parport_ieee1284_read_byte,
.owner = THIS_MODULE,
};
/* --- Mode detection ------------------------------------- */
/*
* Checks for port existence, all ports support SPP MODE
*/
static int __devinit parport_SPP_supported(struct parport *pb)
{
unsigned char r, w;
/*
* first clear an eventually pending EPP timeout
* I (sailer@ife.ee.ethz.ch) have an SMSC chipset
* that does not even respond to SPP cycles if an EPP
* timeout is pending
*/
clear_epp_timeout(pb);
/* Do a simple read-write test to make sure the port exists. */
w = 0xc;
parport_writeb (w, CONTROL (pb));
/* Is there a control register that we can read from? Some
* ports don't allow reads, so read_control just returns a
* software copy. Some ports _do_ allow reads, so bypass the
* software copy here. In addition, some bits aren't
* writable. */
r = parport_readb (CONTROL (pb));
if ((r & 0xf) == w) {
w = 0xe;
parport_writeb (w, CONTROL (pb));
r = parport_readb (CONTROL (pb));
parport_writeb (0xc, CONTROL (pb));
if ((r & 0xf) == w)
return PARPORT_MODE_PCSPP;
}
/* Try the data register. The data lines aren't tri-stated at
* this stage, so we expect back what we wrote. */
w = 0xaa;
parport_gsc_write_data (pb, w);
r = parport_gsc_read_data (pb);
if (r == w) {
w = 0x55;
parport_gsc_write_data (pb, w);
r = parport_gsc_read_data (pb);
if (r == w)
return PARPORT_MODE_PCSPP;
}
return 0;
}
/* Detect PS/2 support.
*
* Bit 5 (0x20) sets the PS/2 data direction; setting this high
* allows us to read data from the data lines. In theory we would get back
* 0xff but any peripheral attached to the port may drag some or all of the
* lines down to zero. So if we get back anything that isn't the contents
* of the data register we deem PS/2 support to be present.
*
* Some SPP ports have "half PS/2" ability - you can't turn off the line
* drivers, but an external peripheral with sufficiently beefy drivers of
* its own can overpower them and assert its own levels onto the bus, from
* where they can then be read back as normal. Ports with this property
* and the right type of device attached are likely to fail the SPP test,
* (as they will appear to have stuck bits) and so the fact that they might
* be misdetected here is rather academic.
*/
static int __devinit parport_PS2_supported(struct parport *pb)
{
int ok = 0;
clear_epp_timeout(pb);
/* try to tri-state the buffer */
parport_gsc_data_reverse (pb);
parport_gsc_write_data(pb, 0x55);
if (parport_gsc_read_data(pb) != 0x55) ok++;
parport_gsc_write_data(pb, 0xaa);
if (parport_gsc_read_data(pb) != 0xaa) ok++;
/* cancel input mode */
parport_gsc_data_forward (pb);
if (ok) {
pb->modes |= PARPORT_MODE_TRISTATE;
} else {
struct parport_gsc_private *priv = pb->private_data;
priv->ctr_writable &= ~0x20;
}
return ok;
}
/* --- Initialisation code -------------------------------- */
struct parport *__devinit parport_gsc_probe_port (unsigned long base,
unsigned long base_hi,
int irq, int dma,
struct pci_dev *dev)
{
struct parport_gsc_private *priv;
struct parport_operations *ops;
struct parport tmp;
struct parport *p = &tmp;
priv = kzalloc (sizeof (struct parport_gsc_private), GFP_KERNEL);
if (!priv) {
printk (KERN_DEBUG "parport (0x%lx): no memory!\n", base);
return NULL;
}
ops = kmalloc (sizeof (struct parport_operations), GFP_KERNEL);
if (!ops) {
printk (KERN_DEBUG "parport (0x%lx): no memory for ops!\n",
base);
kfree (priv);
return NULL;
}
memcpy (ops, &parport_gsc_ops, sizeof (struct parport_operations));
priv->ctr = 0xc;
priv->ctr_writable = 0xff;
priv->dma_buf = 0;
priv->dma_handle = 0;
priv->dev = dev;
p->base = base;
p->base_hi = base_hi;
p->irq = irq;
p->dma = dma;
p->modes = PARPORT_MODE_PCSPP | PARPORT_MODE_SAFEININT;
p->ops = ops;
p->private_data = priv;
p->physport = p;
if (!parport_SPP_supported (p)) {
/* No port. */
kfree (priv);
return NULL;
}
parport_PS2_supported (p);
if (!(p = parport_register_port(base, PARPORT_IRQ_NONE,
PARPORT_DMA_NONE, ops))) {
kfree (priv);
kfree (ops);
return NULL;
}
p->base_hi = base_hi;
p->modes = tmp.modes;
p->size = (p->modes & PARPORT_MODE_EPP)?8:3;
p->private_data = priv;
printk(KERN_INFO "%s: PC-style at 0x%lx", p->name, p->base);
p->irq = irq;
if (p->irq == PARPORT_IRQ_AUTO) {
p->irq = PARPORT_IRQ_NONE;
}
if (p->irq != PARPORT_IRQ_NONE) {
printk(", irq %d", p->irq);
if (p->dma == PARPORT_DMA_AUTO) {
p->dma = PARPORT_DMA_NONE;
}
}
if (p->dma == PARPORT_DMA_AUTO) /* To use DMA, giving the irq
is mandatory (see above) */
p->dma = PARPORT_DMA_NONE;
printk(" [");
#define printmode(x) {if(p->modes&PARPORT_MODE_##x){printk("%s%s",f?",":"",#x);f++;}}
{
int f = 0;
printmode(PCSPP);
printmode(TRISTATE);
printmode(COMPAT)
printmode(EPP);
// printmode(ECP);
// printmode(DMA);
}
#undef printmode
printk("]\n");
if (p->irq != PARPORT_IRQ_NONE) {
if (request_irq (p->irq, parport_gsc_interrupt,
0, p->name, p)) {
printk (KERN_WARNING "%s: irq %d in use, "
"resorting to polled operation\n",
p->name, p->irq);
p->irq = PARPORT_IRQ_NONE;
p->dma = PARPORT_DMA_NONE;
}
}
/* Done probing. Now put the port into a sensible start-up state. */
parport_gsc_write_data(p, 0);
parport_gsc_data_forward (p);
/* Now that we've told the sharing engine about the port, and
found out its characteristics, let the high-level drivers
know about it. */
parport_announce_port (p);
return p;
}
#define PARPORT_GSC_OFFSET 0x800
static int __initdata parport_count;
static int __devinit parport_init_chip(struct parisc_device *dev)
{
struct parport *p;
unsigned long port;
if (!dev->irq) {
printk(KERN_WARNING "IRQ not found for parallel device at 0x%lx\n",
dev->hpa.start);
return -ENODEV;
}
port = dev->hpa.start + PARPORT_GSC_OFFSET;
/* some older machines with ASP-chip don't support
* the enhanced parport modes.
*/
if (boot_cpu_data.cpu_type > pcxt && !pdc_add_valid(port+4)) {
/* Initialize bidirectional-mode (0x10) & data-tranfer-mode #1 (0x20) */
printk("%s: initialize bidirectional-mode.\n", __FUNCTION__);
parport_writeb ( (0x10 + 0x20), port + 4);
} else {
printk("%s: enhanced parport-modes not supported.\n", __FUNCTION__);
}
p = parport_gsc_probe_port(port, 0, dev->irq,
/* PARPORT_IRQ_NONE */ PARPORT_DMA_NONE, NULL);
if (p)
parport_count++;
dev->dev.driver_data = p;
return 0;
}
static int __devexit parport_remove_chip(struct parisc_device *dev)
{
struct parport *p = dev->dev.driver_data;
if (p) {
struct parport_gsc_private *priv = p->private_data;
struct parport_operations *ops = p->ops;
parport_remove_port(p);
if (p->dma != PARPORT_DMA_NONE)
free_dma(p->dma);
if (p->irq != PARPORT_IRQ_NONE)
free_irq(p->irq, p);
if (priv->dma_buf)
pci_free_consistent(priv->dev, PAGE_SIZE,
priv->dma_buf,
priv->dma_handle);
kfree (p->private_data);
parport_put_port(p);
kfree (ops); /* hope no-one cached it */
}
return 0;
}
static struct parisc_device_id parport_tbl[] = {
{ HPHW_FIO, HVERSION_REV_ANY_ID, HVERSION_ANY_ID, 0x74 },
{ 0, }
};
MODULE_DEVICE_TABLE(parisc, parport_tbl);
static struct parisc_driver parport_driver = {
.name = "Parallel",
.id_table = parport_tbl,
.probe = parport_init_chip,
.remove = __devexit_p(parport_remove_chip),
};
int __devinit parport_gsc_init(void)
{
return register_parisc_driver(&parport_driver);
}
static void __devexit parport_gsc_exit(void)
{
unregister_parisc_driver(&parport_driver);
}
module_init(parport_gsc_init);
module_exit(parport_gsc_exit);
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