Root/drivers/parport/daisy.c

1/*
2 * IEEE 1284.3 Parallel port daisy chain and multiplexor code
3 *
4 * Copyright (C) 1999, 2000 Tim Waugh <tim@cyberelk.demon.co.uk>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * ??-12-1998: Initial implementation.
12 * 31-01-1999: Make port-cloning transparent.
13 * 13-02-1999: Move DeviceID technique from parport_probe.
14 * 13-03-1999: Get DeviceID from non-IEEE 1284.3 devices too.
15 * 22-02-2000: Count devices that are actually detected.
16 *
17 * Any part of this program may be used in documents licensed under
18 * the GNU Free Documentation License, Version 1.1 or any later version
19 * published by the Free Software Foundation.
20 */
21
22#include <linux/module.h>
23#include <linux/parport.h>
24#include <linux/delay.h>
25#include <linux/slab.h>
26#include <linux/sched.h>
27
28#include <asm/current.h>
29#include <asm/uaccess.h>
30
31#undef DEBUG
32
33#ifdef DEBUG
34#define DPRINTK(stuff...) printk(stuff)
35#else
36#define DPRINTK(stuff...)
37#endif
38
39static struct daisydev {
40    struct daisydev *next;
41    struct parport *port;
42    int daisy;
43    int devnum;
44} *topology = NULL;
45static DEFINE_SPINLOCK(topology_lock);
46
47static int numdevs = 0;
48
49/* Forward-declaration of lower-level functions. */
50static int mux_present(struct parport *port);
51static int num_mux_ports(struct parport *port);
52static int select_port(struct parport *port);
53static int assign_addrs(struct parport *port);
54
55/* Add a device to the discovered topology. */
56static void add_dev(int devnum, struct parport *port, int daisy)
57{
58    struct daisydev *newdev, **p;
59    newdev = kmalloc(sizeof(struct daisydev), GFP_KERNEL);
60    if (newdev) {
61        newdev->port = port;
62        newdev->daisy = daisy;
63        newdev->devnum = devnum;
64        spin_lock(&topology_lock);
65        for (p = &topology; *p && (*p)->devnum<devnum; p = &(*p)->next)
66            ;
67        newdev->next = *p;
68        *p = newdev;
69        spin_unlock(&topology_lock);
70    }
71}
72
73/* Clone a parport (actually, make an alias). */
74static struct parport *clone_parport(struct parport *real, int muxport)
75{
76    struct parport *extra = parport_register_port(real->base,
77                               real->irq,
78                               real->dma,
79                               real->ops);
80    if (extra) {
81        extra->portnum = real->portnum;
82        extra->physport = real;
83        extra->muxport = muxport;
84        real->slaves[muxport-1] = extra;
85    }
86
87    return extra;
88}
89
90/* Discover the IEEE1284.3 topology on a port -- muxes and daisy chains.
91 * Return value is number of devices actually detected. */
92int parport_daisy_init(struct parport *port)
93{
94    int detected = 0;
95    char *deviceid;
96    static const char *th[] = { /*0*/"th", "st", "nd", "rd", "th" };
97    int num_ports;
98    int i;
99    int last_try = 0;
100
101again:
102    /* Because this is called before any other devices exist,
103     * we don't have to claim exclusive access. */
104
105    /* If mux present on normal port, need to create new
106     * parports for each extra port. */
107    if (port->muxport < 0 && mux_present(port) &&
108        /* don't be fooled: a mux must have 2 or 4 ports. */
109        ((num_ports = num_mux_ports(port)) == 2 || num_ports == 4)) {
110        /* Leave original as port zero. */
111        port->muxport = 0;
112        printk(KERN_INFO
113            "%s: 1st (default) port of %d-way multiplexor\n",
114            port->name, num_ports);
115        for (i = 1; i < num_ports; i++) {
116            /* Clone the port. */
117            struct parport *extra = clone_parport(port, i);
118            if (!extra) {
119                if (signal_pending(current))
120                    break;
121
122                schedule();
123                continue;
124            }
125
126            printk(KERN_INFO
127                "%s: %d%s port of %d-way multiplexor on %s\n",
128                extra->name, i + 1, th[i + 1], num_ports,
129                port->name);
130
131            /* Analyse that port too. We won't recurse
132               forever because of the 'port->muxport < 0'
133               test above. */
134            parport_daisy_init(extra);
135        }
136    }
137
138    if (port->muxport >= 0)
139        select_port(port);
140
141    parport_daisy_deselect_all(port);
142    detected += assign_addrs(port);
143
144    /* Count the potential legacy device at the end. */
145    add_dev(numdevs++, port, -1);
146
147    /* Find out the legacy device's IEEE 1284 device ID. */
148    deviceid = kmalloc(1024, GFP_KERNEL);
149    if (deviceid) {
150        if (parport_device_id(numdevs - 1, deviceid, 1024) > 2)
151            detected++;
152
153        kfree(deviceid);
154    }
155
156    if (!detected && !last_try) {
157        /* No devices were detected. Perhaps they are in some
158                   funny state; let's try to reset them and see if
159                   they wake up. */
160        parport_daisy_fini(port);
161        parport_write_control(port, PARPORT_CONTROL_SELECT);
162        udelay(50);
163        parport_write_control(port,
164                       PARPORT_CONTROL_SELECT |
165                       PARPORT_CONTROL_INIT);
166        udelay(50);
167        last_try = 1;
168        goto again;
169    }
170
171    return detected;
172}
173
174/* Forget about devices on a physical port. */
175void parport_daisy_fini(struct parport *port)
176{
177    struct daisydev **p;
178
179    spin_lock(&topology_lock);
180    p = &topology;
181    while (*p) {
182        struct daisydev *dev = *p;
183        if (dev->port != port) {
184            p = &dev->next;
185            continue;
186        }
187        *p = dev->next;
188        kfree(dev);
189    }
190
191    /* Gaps in the numbering could be handled better. How should
192           someone enumerate through all IEEE1284.3 devices in the
193           topology?. */
194    if (!topology) numdevs = 0;
195    spin_unlock(&topology_lock);
196    return;
197}
198
199/**
200 * parport_open - find a device by canonical device number
201 * @devnum: canonical device number
202 * @name: name to associate with the device
203 *
204 * This function is similar to parport_register_device(), except
205 * that it locates a device by its number rather than by the port
206 * it is attached to.
207 *
208 * All parameters except for @devnum are the same as for
209 * parport_register_device(). The return value is the same as
210 * for parport_register_device().
211 **/
212
213struct pardevice *parport_open(int devnum, const char *name)
214{
215    struct daisydev *p = topology;
216    struct parport *port;
217    struct pardevice *dev;
218    int daisy;
219
220    spin_lock(&topology_lock);
221    while (p && p->devnum != devnum)
222        p = p->next;
223
224    if (!p) {
225        spin_unlock(&topology_lock);
226        return NULL;
227    }
228
229    daisy = p->daisy;
230    port = parport_get_port(p->port);
231    spin_unlock(&topology_lock);
232
233    dev = parport_register_device(port, name, NULL, NULL, NULL, 0, NULL);
234    parport_put_port(port);
235    if (!dev)
236        return NULL;
237
238    dev->daisy = daisy;
239
240    /* Check that there really is a device to select. */
241    if (daisy >= 0) {
242        int selected;
243        parport_claim_or_block(dev);
244        selected = port->daisy;
245        parport_release(dev);
246
247        if (selected != daisy) {
248            /* No corresponding device. */
249            parport_unregister_device(dev);
250            return NULL;
251        }
252    }
253
254    return dev;
255}
256
257/**
258 * parport_close - close a device opened with parport_open()
259 * @dev: device to close
260 *
261 * This is to parport_open() as parport_unregister_device() is to
262 * parport_register_device().
263 **/
264
265void parport_close(struct pardevice *dev)
266{
267    parport_unregister_device(dev);
268}
269
270/* Send a daisy-chain-style CPP command packet. */
271static int cpp_daisy(struct parport *port, int cmd)
272{
273    unsigned char s;
274
275    parport_data_forward(port);
276    parport_write_data(port, 0xaa); udelay(2);
277    parport_write_data(port, 0x55); udelay(2);
278    parport_write_data(port, 0x00); udelay(2);
279    parport_write_data(port, 0xff); udelay(2);
280    s = parport_read_status(port) & (PARPORT_STATUS_BUSY
281                      | PARPORT_STATUS_PAPEROUT
282                      | PARPORT_STATUS_SELECT
283                      | PARPORT_STATUS_ERROR);
284    if (s != (PARPORT_STATUS_BUSY
285          | PARPORT_STATUS_PAPEROUT
286          | PARPORT_STATUS_SELECT
287          | PARPORT_STATUS_ERROR)) {
288        DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff(%02x)\n",
289             port->name, s);
290        return -ENXIO;
291    }
292
293    parport_write_data(port, 0x87); udelay(2);
294    s = parport_read_status(port) & (PARPORT_STATUS_BUSY
295                      | PARPORT_STATUS_PAPEROUT
296                      | PARPORT_STATUS_SELECT
297                      | PARPORT_STATUS_ERROR);
298    if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
299        DPRINTK(KERN_DEBUG "%s: cpp_daisy: aa5500ff87(%02x)\n",
300             port->name, s);
301        return -ENXIO;
302    }
303
304    parport_write_data(port, 0x78); udelay(2);
305    parport_write_data(port, cmd); udelay(2);
306    parport_frob_control(port,
307                  PARPORT_CONTROL_STROBE,
308                  PARPORT_CONTROL_STROBE);
309    udelay(1);
310    s = parport_read_status(port);
311    parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
312    udelay(1);
313    parport_write_data(port, 0xff); udelay(2);
314
315    return s;
316}
317
318/* Send a mux-style CPP command packet. */
319static int cpp_mux(struct parport *port, int cmd)
320{
321    unsigned char s;
322    int rc;
323
324    parport_data_forward(port);
325    parport_write_data(port, 0xaa); udelay(2);
326    parport_write_data(port, 0x55); udelay(2);
327    parport_write_data(port, 0xf0); udelay(2);
328    parport_write_data(port, 0x0f); udelay(2);
329    parport_write_data(port, 0x52); udelay(2);
330    parport_write_data(port, 0xad); udelay(2);
331    parport_write_data(port, cmd); udelay(2);
332
333    s = parport_read_status(port);
334    if (!(s & PARPORT_STATUS_ACK)) {
335        DPRINTK(KERN_DEBUG "%s: cpp_mux: aa55f00f52ad%02x(%02x)\n",
336             port->name, cmd, s);
337        return -EIO;
338    }
339
340    rc = (((s & PARPORT_STATUS_SELECT ? 1 : 0) << 0) |
341          ((s & PARPORT_STATUS_PAPEROUT ? 1 : 0) << 1) |
342          ((s & PARPORT_STATUS_BUSY ? 0 : 1) << 2) |
343          ((s & PARPORT_STATUS_ERROR ? 0 : 1) << 3));
344
345    return rc;
346}
347
348void parport_daisy_deselect_all(struct parport *port)
349{
350    cpp_daisy(port, 0x30);
351}
352
353int parport_daisy_select(struct parport *port, int daisy, int mode)
354{
355    switch (mode)
356    {
357        // For these modes we should switch to EPP mode:
358        case IEEE1284_MODE_EPP:
359        case IEEE1284_MODE_EPPSL:
360        case IEEE1284_MODE_EPPSWE:
361            return !(cpp_daisy(port, 0x20 + daisy) &
362                 PARPORT_STATUS_ERROR);
363
364        // For these modes we should switch to ECP mode:
365        case IEEE1284_MODE_ECP:
366        case IEEE1284_MODE_ECPRLE:
367        case IEEE1284_MODE_ECPSWE:
368            return !(cpp_daisy(port, 0xd0 + daisy) &
369                 PARPORT_STATUS_ERROR);
370
371        // Nothing was told for BECP in Daisy chain specification.
372        // May be it's wise to use ECP?
373        case IEEE1284_MODE_BECP:
374        // Others use compat mode
375        case IEEE1284_MODE_NIBBLE:
376        case IEEE1284_MODE_BYTE:
377        case IEEE1284_MODE_COMPAT:
378        default:
379            return !(cpp_daisy(port, 0xe0 + daisy) &
380                 PARPORT_STATUS_ERROR);
381    }
382}
383
384static int mux_present(struct parport *port)
385{
386    return cpp_mux(port, 0x51) == 3;
387}
388
389static int num_mux_ports(struct parport *port)
390{
391    return cpp_mux(port, 0x58);
392}
393
394static int select_port(struct parport *port)
395{
396    int muxport = port->muxport;
397    return cpp_mux(port, 0x60 + muxport) == muxport;
398}
399
400static int assign_addrs(struct parport *port)
401{
402    unsigned char s;
403    unsigned char daisy;
404    int thisdev = numdevs;
405    int detected;
406    char *deviceid;
407
408    parport_data_forward(port);
409    parport_write_data(port, 0xaa); udelay(2);
410    parport_write_data(port, 0x55); udelay(2);
411    parport_write_data(port, 0x00); udelay(2);
412    parport_write_data(port, 0xff); udelay(2);
413    s = parport_read_status(port) & (PARPORT_STATUS_BUSY
414                      | PARPORT_STATUS_PAPEROUT
415                      | PARPORT_STATUS_SELECT
416                      | PARPORT_STATUS_ERROR);
417    if (s != (PARPORT_STATUS_BUSY
418          | PARPORT_STATUS_PAPEROUT
419          | PARPORT_STATUS_SELECT
420          | PARPORT_STATUS_ERROR)) {
421        DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff(%02x)\n",
422             port->name, s);
423        return 0;
424    }
425
426    parport_write_data(port, 0x87); udelay(2);
427    s = parport_read_status(port) & (PARPORT_STATUS_BUSY
428                      | PARPORT_STATUS_PAPEROUT
429                      | PARPORT_STATUS_SELECT
430                      | PARPORT_STATUS_ERROR);
431    if (s != (PARPORT_STATUS_SELECT | PARPORT_STATUS_ERROR)) {
432        DPRINTK(KERN_DEBUG "%s: assign_addrs: aa5500ff87(%02x)\n",
433             port->name, s);
434        return 0;
435    }
436
437    parport_write_data(port, 0x78); udelay(2);
438    s = parport_read_status(port);
439
440    for (daisy = 0;
441         (s & (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT))
442             == (PARPORT_STATUS_PAPEROUT|PARPORT_STATUS_SELECT)
443             && daisy < 4;
444         ++daisy) {
445        parport_write_data(port, daisy);
446        udelay(2);
447        parport_frob_control(port,
448                      PARPORT_CONTROL_STROBE,
449                      PARPORT_CONTROL_STROBE);
450        udelay(1);
451        parport_frob_control(port, PARPORT_CONTROL_STROBE, 0);
452        udelay(1);
453
454        add_dev(numdevs++, port, daisy);
455
456        /* See if this device thought it was the last in the
457         * chain. */
458        if (!(s & PARPORT_STATUS_BUSY))
459            break;
460
461        /* We are seeing pass through status now. We see
462           last_dev from next device or if last_dev does not
463           work status lines from some non-daisy chain
464           device. */
465        s = parport_read_status(port);
466    }
467
468    parport_write_data(port, 0xff); udelay(2);
469    detected = numdevs - thisdev;
470    DPRINTK(KERN_DEBUG "%s: Found %d daisy-chained devices\n", port->name,
471         detected);
472
473    /* Ask the new devices to introduce themselves. */
474    deviceid = kmalloc(1024, GFP_KERNEL);
475    if (!deviceid) return 0;
476
477    for (daisy = 0; thisdev < numdevs; thisdev++, daisy++)
478        parport_device_id(thisdev, deviceid, 1024);
479
480    kfree(deviceid);
481    return detected;
482}
483

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