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kernel/drivers/parport/daisy.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/slab.h>
#include <linux/sched/signal.h>
#include <asm/current.h>
#include <linux/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;
/* 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
*
* 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)
{
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, NULL, NULL, NULL, 0, NULL);
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);
}
/* 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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