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linux/drivers/parport/daisy.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

520 lines
13 KiB
C
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/*
* IEEE 1284.3 Parallel port daisy chain and multiplexor code
*
* Copyright (C) 1999, 2000 Tim Waugh <tim@cyberelk.demon.co.uk>
*
* 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.
*
* ??-12-1998: Initial implementation.
* 31-01-1999: Make port-cloning transparent.
* 13-02-1999: Move DeviceID technique from parport_probe.
* 13-03-1999: Get DeviceID from non-IEEE 1284.3 devices too.
* 22-02-2000: Count devices that are actually detected.
*
* Any part of this program may be used in documents licensed under
* the GNU Free Documentation License, Version 1.1 or any later version
* published by the Free Software Foundation.
*/
#include <linux/module.h>
#include <linux/parport.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <asm/current.h>
#include <asm/uaccess.h>
#undef DEBUG
#ifdef DEBUG
#define DPRINTK(stuff...) printk(stuff)
#else
#define DPRINTK(stuff...)
#endif
static struct daisydev {
struct daisydev *next;
struct parport *port;
int daisy;
int devnum;
} *topology = NULL;
static DEFINE_SPINLOCK(topology_lock);
static int numdevs = 0;
/* Forward-declaration of lower-level functions. */
static int mux_present(struct parport *port);
static int num_mux_ports(struct parport *port);
static int select_port(struct parport *port);
static int assign_addrs(struct parport *port);
/* Add a device to the discovered topology. */
static void add_dev(int devnum, struct parport *port, int daisy)
{
struct daisydev *newdev, **p;
newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL);
if (newdev) {
newdev->port = port;
newdev->daisy = daisy;
newdev->devnum = devnum;
spin_lock(&topology_lock);
for (p = &topology; *p && (*p)->devnum<devnum; p = &(*p)->next)
;
newdev->next = *p;
*p = newdev;
spin_unlock(&topology_lock);
}
}
/* Clone a parport (actually, make an alias). */
static struct parport *clone_parport(struct parport *real, int muxport)
{
struct parport *extra = parport_register_port(real->base,
real->irq,
real->dma,
real->ops);
if (extra) {
extra->portnum = real->portnum;
extra->physport = real;
extra->muxport = muxport;
real->slaves[muxport-1] = extra;
}
return extra;
}
/* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains.
* Return value is number of devices actually detected. */
int parport_daisy_init(struct parport *port)
{
int detected = 0;
char *deviceid;
static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" };
int num_ports;
int i;
int last_try = 0;
again:
/* Because this is called before any other devices exist,
* we don't have to claim exclusive access. */
/* If mux present on normal port, need to create new
* parports for each extra port. */
if (port->muxport < 0 && mux_present(port) &&
/* don't be fooled: a mux must have 2 or 4 ports. */
((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) {
/* Leave original as port zero. */
port->muxport = 0;
printk(KERN_INFO
"%s: 1st (default) port of %d-way multiplexor\n",
port->name, num_ports);
for (i = 1; i < num_ports; i++) {
/* Clone the port. */
struct parport *extra = clone_parport(port, i);
if (!extra) {
if (signal_pending(current))
break;
schedule();
continue;
}
printk(KERN_INFO
"%s: %d%s port of %d-way multiplexor on %s\n",
extra->name, i + 1, th[i + 1], num_ports,
port->name);
/* Analyse that port too. We won't recurse
forever because of the 'port->muxport < 0'
test above. */
parport_daisy_init(extra);
}
}
if (port->muxport >= 0)
select_port(port);
parport_daisy_deselect_all(port);
detected += assign_addrs(port);
/* Count the potential legacy device at the end. */
add_dev(numdevs++, port, -1);
/* Find out the legacy device's IEEE 1284 device ID. */
deviceid = kmalloc(1024, GFP_KERNEL);
if (deviceid) {
if (parport_device_id(numdevs - 1, deviceid, 1024) > 2)
detected++;
kfree(deviceid);
}
if (!detected && !last_try) {
/* No devices were detected. Perhaps they are in some
funny state; let's try to reset them and see if
they wake up. */
parport_daisy_fini(port);
parport_write_control(port, PARPORT_CONTROL_SELECT);
udelay(50);
parport_write_control(port,
PARPORT_CONTROL_SELECT |
PARPORT_CONTROL_INIT);
udelay(50);
last_try = 1;
goto again;
}
return detected;
}
/* Forget about devices on a physical port. */
void parport_daisy_fini(struct parport *port)
{
struct daisydev **p;
spin_lock(&topology_lock);
p = &topology;
while (*p) {
struct daisydev *dev = *p;
if (dev->port != port) {
p = &dev->next;
continue;
}
*p = dev->next;
kfree(dev);
}
/* Gaps in the numbering could be handled better. How should
someone enumerate through all IEEE1284.3 devices in the
topology?. */
if (!topology) numdevs = 0;
spin_unlock(&topology_lock);
return;
}
/**
* parport_open - find a device by canonical device number
* @devnum: canonical device number
* @name: name to associate with the device
* @pf: preemption callback
* @kf: kick callback
* @irqf: interrupt handler
* @flags: registration flags
* @handle: driver data
*
* This function is similar to parport_register_device(), except
* that it locates a device by its number rather than by the port
* it is attached to.
*
* All parameters except for @devnum are the same as for
* parport_register_device(). The return value is the same as
* for parport_register_device().
**/
struct pardevice *parport_open(int devnum, const char *name,
int (*pf) (void *), void (*kf) (void *),
void (*irqf) (int, void *),
int flags, void *handle)
{
struct daisydev *p = topology;
struct parport *port;
struct pardevice *dev;
int daisy;
spin_lock(&topology_lock);
while (p && p->devnum != devnum)
p = p->next;
if (!p) {
spin_unlock(&topology_lock);
return NULL;
}
daisy = p->daisy;
port = parport_get_port(p->port);
spin_unlock(&topology_lock);
dev = parport_register_device(port, name, pf, kf,
irqf, flags, handle);
parport_put_port(port);
if (!dev)
return NULL;
dev->daisy = daisy;
/* Check that there really is a device to select. */
if (daisy >= 0) {
int selected;
parport_claim_or_block(dev);
selected = port->daisy;
parport_release(dev);
if (selected != daisy) {
/* No corresponding device. */
parport_unregister_device(dev);
return NULL;
}
}
return dev;
}
/**
* parport_close - close a device opened with parport_open()
* @dev: device to close
*
* This is to parport_open() as parport_unregister_device() is to
* parport_register_device().
**/
void parport_close(struct pardevice *dev)
{
parport_unregister_device(dev);
}
/**
* parport_device_num - convert device coordinates
* @parport: parallel port number
* @mux: multiplexor port number (-1 for no multiplexor)
* @daisy: daisy chain address (-1 for no daisy chain address)
*
* This tries to locate a device on the given parallel port,
* multiplexor port and daisy chain address, and returns its
* device number or %-ENXIO if no device with those coordinates
* exists.
**/
int parport_device_num(int parport, int mux, int daisy)
{
int res = -ENXIO;
struct daisydev *dev;
spin_lock(&topology_lock);
dev = topology;
while (dev && dev->port->portnum != parport &&
dev->port->muxport != mux && dev->daisy != daisy)
dev = dev->next;
if (dev)
res = dev->devnum;
spin_unlock(&topology_lock);
return res;
}
/* Send a daisy-chain-style CPP command packet. */
static int cpp_daisy(struct parport *port, int cmd)
{
unsigned char s;
parport_data_forward(port);
parport_write_data(port, 0xaa); udelay(2);
parport_write_data(port, 0x55); udelay(2);
parport_write_data(port, 0x00); udelay(2);
parport_write_data(port, 0xff); udelay(2);
s = parport_read_status(port) & (PARPORT_STATUS_BUSY
| PARPORT_STATUS_PAPEROUT
| PARPORT_STATUS_SELECT
| PARPORT_STATUS_ERROR);
if (s != (PARPORT_STATUS_BUSY
| PARPORT_STATUS_PAPEROUT
| PARPORT_STATUS_SELECT
| PARPORT_STATUS_ERROR)) {
DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff(%02x)\n",
port->name, s);
return -ENXIO;
}
parport_write_data(port, 0x87); udelay(2);
s = parport_read_status(port) & (PARPORT_STATUS_BUSY
| PARPORT_STATUS_PAPEROUT
| PARPORT_STATUS_SELECT
| PARPORT_STATUS_ERROR);
if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff87(%02x)\n",
port->name, s);
return -ENXIO;
}
parport_write_data(port, 0x78); udelay(2);
parport_write_data(port, cmd); udelay(2);
parport_frob_control(port,
PARPORT_CONTROL_STROBE,
PARPORT_CONTROL_STROBE);
udelay(1);
s = parport_read_status(port);
parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
udelay(1);
parport_write_data(port, 0xff); udelay(2);
return s;
}
/* Send a mux-style CPP command packet. */
static int cpp_mux(struct parport *port, int cmd)
{
unsigned char s;
int rc;
parport_data_forward(port);
parport_write_data(port, 0xaa); udelay(2);
parport_write_data(port, 0x55); udelay(2);
parport_write_data(port, 0xf0); udelay(2);
parport_write_data(port, 0x0f); udelay(2);
parport_write_data(port, 0x52); udelay(2);
parport_write_data(port, 0xad); udelay(2);
parport_write_data(port, cmd); udelay(2);
s = parport_read_status(port);
if (!(s & PARPORT_STATUS_ACK)) {
DPRINTK(KERN_DEBUG "%s: cpp_mux: aa55f00f52ad%02x(%02x)\n",
port->name, cmd, s);
return -EIO;
}
rc = (((s & PARPORT_STATUS_SELECT ? 1 : 0) << 0) |
((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) |
((s & PARPORT_STATUS_BUSY ? 0 : 1) << 2) |
((s & PARPORT_STATUS_ERROR ? 0 : 1) << 3));
return rc;
}
void parport_daisy_deselect_all(struct parport *port)
{
cpp_daisy(port, 0x30);
}
int parport_daisy_select(struct parport *port, int daisy, int mode)
{
switch (mode)
{
// For these modes we should switch to EPP mode:
case IEEE1284_MODE_EPP:
case IEEE1284_MODE_EPPSL:
case IEEE1284_MODE_EPPSWE:
return !(cpp_daisy(port, 0x20 + daisy) &
PARPORT_STATUS_ERROR);
// For these modes we should switch to ECP mode:
case IEEE1284_MODE_ECP:
case IEEE1284_MODE_ECPRLE:
case IEEE1284_MODE_ECPSWE:
return !(cpp_daisy(port, 0xd0 + daisy) &
PARPORT_STATUS_ERROR);
// Nothing was told for BECP in Daisy chain specification.
// May be it's wise to use ECP?
case IEEE1284_MODE_BECP:
// Others use compat mode
case IEEE1284_MODE_NIBBLE:
case IEEE1284_MODE_BYTE:
case IEEE1284_MODE_COMPAT:
default:
return !(cpp_daisy(port, 0xe0 + daisy) &
PARPORT_STATUS_ERROR);
}
}
static int mux_present(struct parport *port)
{
return cpp_mux(port, 0x51) == 3;
}
static int num_mux_ports(struct parport *port)
{
return cpp_mux(port, 0x58);
}
static int select_port(struct parport *port)
{
int muxport = port->muxport;
return cpp_mux(port, 0x60 + muxport) == muxport;
}
static int assign_addrs(struct parport *port)
{
unsigned char s;
unsigned char daisy;
int thisdev = numdevs;
int detected;
char *deviceid;
parport_data_forward(port);
parport_write_data(port, 0xaa); udelay(2);
parport_write_data(port, 0x55); udelay(2);
parport_write_data(port, 0x00); udelay(2);
parport_write_data(port, 0xff); udelay(2);
s = parport_read_status(port) & (PARPORT_STATUS_BUSY
| PARPORT_STATUS_PAPEROUT
| PARPORT_STATUS_SELECT
| PARPORT_STATUS_ERROR);
if (s != (PARPORT_STATUS_BUSY
| PARPORT_STATUS_PAPEROUT
| PARPORT_STATUS_SELECT
| PARPORT_STATUS_ERROR)) {
DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff(%02x)\n",
port->name, s);
return 0;
}
parport_write_data(port, 0x87); udelay(2);
s = parport_read_status(port) & (PARPORT_STATUS_BUSY
| PARPORT_STATUS_PAPEROUT
| PARPORT_STATUS_SELECT
| PARPORT_STATUS_ERROR);
if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff87(%02x)\n",
port->name, s);
return 0;
}
parport_write_data(port, 0x78); udelay(2);
s = parport_read_status(port);
for (daisy = 0;
(s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))
== (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)
&& daisy < 4;
++daisy) {
parport_write_data(port, daisy);
udelay(2);
parport_frob_control(port,
PARPORT_CONTROL_STROBE,
PARPORT_CONTROL_STROBE);
udelay(1);
parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
udelay(1);
add_dev(numdevs++, port, daisy);
/* See if this device thought it was the last in the
* chain. */
if (!(s & PARPORT_STATUS_BUSY))
break;
/* We are seeing pass through status now. We see
last_dev from next device or if last_dev does not
work status lines from some non-daisy chain
device. */
s = parport_read_status(port);
}
parport_write_data(port, 0xff); udelay(2);
detected = numdevs - thisdev;
DPRINTK(KERN_DEBUG "%s: Found %d daisy-chained devices\n", port->name,
detected);
/* Ask the new devices to introduce themselves. */
deviceid = kmalloc(1024, GFP_KERNEL);
if (!deviceid) return 0;
for (daisy = 0; thisdev < numdevs; thisdev++, daisy++)
parport_device_id(thisdev, deviceid, 1024);
kfree(deviceid);
return detected;
}
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