2 * drivers/s390/cio/css.c
3 * driver for channel subsystem
5 * Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
7 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
8 * Cornelia Huck (cornelia.huck@de.ibm.com)
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/device.h>
13 #include <linux/slab.h>
14 #include <linux/errno.h>
15 #include <linux/list.h>
19 #include "cio_debug.h"
25 int css_init_done
= 0;
26 static int need_reprobe
= 0;
27 static int max_ssid
= 0;
29 struct channel_subsystem
*css
[__MAX_CSSID
+ 1];
31 int css_characteristics_avail
= 0;
34 for_each_subchannel(int(*fn
)(struct subchannel_id
, void *), void *data
)
36 struct subchannel_id schid
;
39 init_subchannel_id(&schid
);
43 ret
= fn(schid
, data
);
46 } while (schid
.sch_no
++ < __MAX_SUBCHANNEL
);
48 } while (schid
.ssid
++ < max_ssid
);
52 static struct subchannel
*
53 css_alloc_subchannel(struct subchannel_id schid
)
55 struct subchannel
*sch
;
58 sch
= kmalloc (sizeof (*sch
), GFP_KERNEL
| GFP_DMA
);
60 return ERR_PTR(-ENOMEM
);
61 ret
= cio_validate_subchannel (sch
, schid
);
67 if (sch
->st
!= SUBCHANNEL_TYPE_IO
) {
68 /* For now we ignore all non-io subchannels. */
70 return ERR_PTR(-EINVAL
);
74 * Set intparm to subchannel address.
75 * This is fine even on 64bit since the subchannel is always located
78 sch
->schib
.pmcw
.intparm
= (__u32
)(unsigned long)sch
;
79 ret
= cio_modify(sch
);
88 css_free_subchannel(struct subchannel
*sch
)
91 /* Reset intparm to zeroes. */
92 sch
->schib
.pmcw
.intparm
= 0;
100 css_subchannel_release(struct device
*dev
)
102 struct subchannel
*sch
;
104 sch
= to_subchannel(dev
);
105 if (!cio_is_console(sch
->schid
))
109 extern int css_get_ssd_info(struct subchannel
*sch
);
112 int css_sch_device_register(struct subchannel
*sch
)
116 mutex_lock(&sch
->reg_mutex
);
117 ret
= device_register(&sch
->dev
);
118 mutex_unlock(&sch
->reg_mutex
);
122 void css_sch_device_unregister(struct subchannel
*sch
)
124 mutex_lock(&sch
->reg_mutex
);
125 device_unregister(&sch
->dev
);
126 mutex_unlock(&sch
->reg_mutex
);
130 css_register_subchannel(struct subchannel
*sch
)
134 /* Initialize the subchannel structure */
135 sch
->dev
.parent
= &css
[0]->device
;
136 sch
->dev
.bus
= &css_bus_type
;
137 sch
->dev
.release
= &css_subchannel_release
;
139 /* make it known to the system */
140 ret
= css_sch_device_register(sch
);
142 printk (KERN_WARNING
"%s: could not register %s\n",
143 __func__
, sch
->dev
.bus_id
);
145 css_get_ssd_info(sch
);
150 css_probe_device(struct subchannel_id schid
)
153 struct subchannel
*sch
;
155 sch
= css_alloc_subchannel(schid
);
158 ret
= css_register_subchannel(sch
);
160 css_free_subchannel(sch
);
165 check_subchannel(struct device
* dev
, void * data
)
167 struct subchannel
*sch
;
168 struct subchannel_id
*schid
= data
;
170 sch
= to_subchannel(dev
);
171 return schid_equal(&sch
->schid
, schid
);
175 get_subchannel_by_schid(struct subchannel_id schid
)
179 dev
= bus_find_device(&css_bus_type
, NULL
,
180 &schid
, check_subchannel
);
182 return dev
? to_subchannel(dev
) : NULL
;
185 static inline int css_get_subchannel_status(struct subchannel
*sch
)
189 if (stsch(sch
->schid
, &schib
) || !schib
.pmcw
.dnv
)
191 if (sch
->schib
.pmcw
.dnv
&& (schib
.pmcw
.dev
!= sch
->schib
.pmcw
.dev
))
192 return CIO_REVALIDATE
;
198 static int css_evaluate_known_subchannel(struct subchannel
*sch
, int slow
)
200 int event
, ret
, disc
;
202 enum { NONE
, UNREGISTER
, UNREGISTER_PROBE
, REPROBE
} action
;
204 spin_lock_irqsave(&sch
->lock
, flags
);
205 disc
= device_is_disconnected(sch
);
207 /* Disconnected devices are evaluated directly only.*/
208 spin_unlock_irqrestore(&sch
->lock
, flags
);
211 /* No interrupt after machine check - kill pending timers. */
212 device_kill_pending_timer(sch
);
213 if (!disc
&& !slow
) {
214 /* Non-disconnected devices are evaluated on the slow path. */
215 spin_unlock_irqrestore(&sch
->lock
, flags
);
218 event
= css_get_subchannel_status(sch
);
219 CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
220 sch
->schid
.ssid
, sch
->schid
.sch_no
, event
,
221 disc
? "disconnected" : "normal",
222 slow
? "slow" : "fast");
223 /* Analyze subchannel status. */
228 /* Check if paths have become available. */
234 /* Prevent unwanted effects when opening lock. */
235 cio_disable_subchannel(sch
);
236 device_set_disconnected(sch
);
237 /* Ask driver what to do with device. */
239 if (sch
->driver
&& sch
->driver
->notify
) {
240 spin_unlock_irqrestore(&sch
->lock
, flags
);
241 ret
= sch
->driver
->notify(&sch
->dev
, event
);
242 spin_lock_irqsave(&sch
->lock
, flags
);
248 /* Device will be removed, so no notify necessary. */
250 /* Reprobe because immediate unregister might block. */
253 action
= UNREGISTER_PROBE
;
257 /* Get device operational again. */
261 /* Perform action. */
265 case UNREGISTER_PROBE
:
266 /* Unregister device (will use subchannel lock). */
267 spin_unlock_irqrestore(&sch
->lock
, flags
);
268 css_sch_device_unregister(sch
);
269 spin_lock_irqsave(&sch
->lock
, flags
);
271 /* Reset intparm to zeroes. */
272 sch
->schib
.pmcw
.intparm
= 0;
276 device_trigger_reprobe(sch
);
281 spin_unlock_irqrestore(&sch
->lock
, flags
);
282 /* Probe if necessary. */
283 if (action
== UNREGISTER_PROBE
)
284 ret
= css_probe_device(sch
->schid
);
289 static int css_evaluate_new_subchannel(struct subchannel_id schid
, int slow
)
294 /* Will be done on the slow path. */
297 if (stsch(schid
, &schib
) || !schib
.pmcw
.dnv
) {
298 /* Unusable - ignore. */
301 CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
302 "slow path.\n", schid
.ssid
, schid
.sch_no
, CIO_OPER
);
304 return css_probe_device(schid
);
307 static int css_evaluate_subchannel(struct subchannel_id schid
, int slow
)
309 struct subchannel
*sch
;
312 sch
= get_subchannel_by_schid(schid
);
314 ret
= css_evaluate_known_subchannel(sch
, slow
);
315 put_device(&sch
->dev
);
317 ret
= css_evaluate_new_subchannel(schid
, slow
);
323 css_rescan_devices(struct subchannel_id schid
, void *data
)
325 return css_evaluate_subchannel(schid
, 1);
328 struct slow_subchannel
{
329 struct list_head slow_list
;
330 struct subchannel_id schid
;
333 static LIST_HEAD(slow_subchannels_head
);
334 static DEFINE_SPINLOCK(slow_subchannel_lock
);
337 css_trigger_slow_path(struct work_struct
*unused
)
339 CIO_TRACE_EVENT(4, "slowpath");
343 for_each_subchannel(css_rescan_devices
, NULL
);
347 spin_lock_irq(&slow_subchannel_lock
);
348 while (!list_empty(&slow_subchannels_head
)) {
349 struct slow_subchannel
*slow_sch
=
350 list_entry(slow_subchannels_head
.next
,
351 struct slow_subchannel
, slow_list
);
353 list_del_init(slow_subchannels_head
.next
);
354 spin_unlock_irq(&slow_subchannel_lock
);
355 css_evaluate_subchannel(slow_sch
->schid
, 1);
356 spin_lock_irq(&slow_subchannel_lock
);
359 spin_unlock_irq(&slow_subchannel_lock
);
362 DECLARE_WORK(slow_path_work
, css_trigger_slow_path
);
363 struct workqueue_struct
*slow_path_wq
;
365 /* Reprobe subchannel if unregistered. */
366 static int reprobe_subchannel(struct subchannel_id schid
, void *data
)
368 struct subchannel
*sch
;
371 CIO_DEBUG(KERN_INFO
, 6, "cio: reprobe 0.%x.%04x\n",
372 schid
.ssid
, schid
.sch_no
);
376 sch
= get_subchannel_by_schid(schid
);
379 put_device(&sch
->dev
);
383 ret
= css_probe_device(schid
);
389 /* These should abort looping */
398 /* Work function used to reprobe all unregistered subchannels. */
399 static void reprobe_all(struct work_struct
*unused
)
403 CIO_MSG_EVENT(2, "reprobe start\n");
406 /* Make sure initial subchannel scan is done. */
407 wait_event(ccw_device_init_wq
,
408 atomic_read(&ccw_device_init_count
) == 0);
409 ret
= for_each_subchannel(reprobe_subchannel
, NULL
);
411 CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret
,
415 DECLARE_WORK(css_reprobe_work
, reprobe_all
);
417 /* Schedule reprobing of all unregistered subchannels. */
418 void css_schedule_reprobe(void)
421 queue_work(ccw_device_work
, &css_reprobe_work
);
424 EXPORT_SYMBOL_GPL(css_schedule_reprobe
);
427 * Rescan for new devices. FIXME: This is slow.
428 * This function is called when we have lost CRWs due to overflows and we have
429 * to do subchannel housekeeping.
432 css_reiterate_subchannels(void)
434 css_clear_subchannel_slow_list();
439 * Called from the machine check handler for subchannel report words.
442 css_process_crw(int rsid1
, int rsid2
)
445 struct subchannel_id mchk_schid
;
447 CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
451 /* We need to iterate all subchannels anyway. */
454 init_subchannel_id(&mchk_schid
);
455 mchk_schid
.sch_no
= rsid1
;
457 mchk_schid
.ssid
= (rsid2
>> 8) & 3;
460 * Since we are always presented with IPI in the CRW, we have to
461 * use stsch() to find out if the subchannel in question has come
464 ret
= css_evaluate_subchannel(mchk_schid
, 0);
465 if (ret
== -EAGAIN
) {
466 if (css_enqueue_subchannel_slow(mchk_schid
)) {
467 css_clear_subchannel_slow_list();
475 __init_channel_subsystem(struct subchannel_id schid
, void *data
)
477 struct subchannel
*sch
;
480 if (cio_is_console(schid
))
481 sch
= cio_get_console_subchannel();
483 sch
= css_alloc_subchannel(schid
);
492 panic("Out of memory in init_channel_subsystem\n");
493 /* -ENXIO: no more subchannels. */
496 /* -EIO: this subchannel set not supported. */
504 * We register ALL valid subchannels in ioinfo, even those
505 * that have been present before init_channel_subsystem.
506 * These subchannels can't have been registered yet (kmalloc
507 * not working) so we do it now. This is true e.g. for the
508 * console subchannel.
510 css_register_subchannel(sch
);
515 css_generate_pgid(struct channel_subsystem
*css
, u32 tod_high
)
517 if (css_characteristics_avail
&& css_general_characteristics
.mcss
) {
518 css
->global_pgid
.pgid_high
.ext_cssid
.version
= 0x80;
519 css
->global_pgid
.pgid_high
.ext_cssid
.cssid
= css
->cssid
;
522 css
->global_pgid
.pgid_high
.cpu_addr
= hard_smp_processor_id();
524 css
->global_pgid
.pgid_high
.cpu_addr
= 0;
527 css
->global_pgid
.cpu_id
= ((cpuid_t
*) __LC_CPUID
)->ident
;
528 css
->global_pgid
.cpu_model
= ((cpuid_t
*) __LC_CPUID
)->machine
;
529 css
->global_pgid
.tod_high
= tod_high
;
534 channel_subsystem_release(struct device
*dev
)
536 struct channel_subsystem
*css
;
539 mutex_destroy(&css
->mutex
);
544 css_cm_enable_show(struct device
*dev
, struct device_attribute
*attr
,
547 struct channel_subsystem
*css
= to_css(dev
);
551 return sprintf(buf
, "%x\n", css
->cm_enabled
);
555 css_cm_enable_store(struct device
*dev
, struct device_attribute
*attr
,
556 const char *buf
, size_t count
)
558 struct channel_subsystem
*css
= to_css(dev
);
563 ret
= css
->cm_enabled
? chsc_secm(css
, 0) : 0;
566 ret
= css
->cm_enabled
? 0 : chsc_secm(css
, 1);
571 return ret
< 0 ? ret
: count
;
574 static DEVICE_ATTR(cm_enable
, 0644, css_cm_enable_show
, css_cm_enable_store
);
576 static inline void __init
581 memset(css
[nr
], 0, sizeof(struct channel_subsystem
));
582 mutex_init(&css
[nr
]->mutex
);
585 sprintf(css
[nr
]->device
.bus_id
, "css%x", nr
);
586 css
[nr
]->device
.release
= channel_subsystem_release
;
587 tod_high
= (u32
) (get_clock() >> 32);
588 css_generate_pgid(css
[nr
], tod_high
);
592 * Now that the driver core is running, we can setup our channel subsystem.
593 * The struct subchannel's are created during probing (except for the
594 * static console subchannel).
597 init_channel_subsystem (void)
601 if (chsc_determine_css_characteristics() == 0)
602 css_characteristics_avail
= 1;
604 if ((ret
= bus_register(&css_bus_type
)))
607 /* Try to enable MSS. */
608 ret
= chsc_enable_facility(CHSC_SDA_OC_MSS
);
610 case 0: /* Success. */
611 max_ssid
= __MAX_SSID
;
618 /* Setup css structure. */
619 for (i
= 0; i
<= __MAX_CSSID
; i
++) {
620 css
[i
] = kmalloc(sizeof(struct channel_subsystem
), GFP_KERNEL
);
626 ret
= device_register(&css
[i
]->device
);
629 if (css_characteristics_avail
&&
630 css_chsc_characteristics
.secm
) {
631 ret
= device_create_file(&css
[i
]->device
,
632 &dev_attr_cm_enable
);
641 for_each_subchannel(__init_channel_subsystem
, NULL
);
644 device_unregister(&css
[i
]->device
);
650 if (css_characteristics_avail
&& css_chsc_characteristics
.secm
)
651 device_remove_file(&css
[i
]->device
,
652 &dev_attr_cm_enable
);
653 device_unregister(&css
[i
]->device
);
656 bus_unregister(&css_bus_type
);
662 * find a driver for a subchannel. They identify by the subchannel
663 * type with the exception that the console subchannel driver has its own
664 * subchannel type although the device is an i/o subchannel
667 css_bus_match (struct device
*dev
, struct device_driver
*drv
)
669 struct subchannel
*sch
= container_of (dev
, struct subchannel
, dev
);
670 struct css_driver
*driver
= container_of (drv
, struct css_driver
, drv
);
672 if (sch
->st
== driver
->subchannel_type
)
679 css_probe (struct device
*dev
)
681 struct subchannel
*sch
;
683 sch
= to_subchannel(dev
);
684 sch
->driver
= container_of (dev
->driver
, struct css_driver
, drv
);
685 return (sch
->driver
->probe
? sch
->driver
->probe(sch
) : 0);
689 css_remove (struct device
*dev
)
691 struct subchannel
*sch
;
693 sch
= to_subchannel(dev
);
694 return (sch
->driver
->remove
? sch
->driver
->remove(sch
) : 0);
698 css_shutdown (struct device
*dev
)
700 struct subchannel
*sch
;
702 sch
= to_subchannel(dev
);
703 if (sch
->driver
->shutdown
)
704 sch
->driver
->shutdown(sch
);
707 struct bus_type css_bus_type
= {
709 .match
= css_bus_match
,
711 .remove
= css_remove
,
712 .shutdown
= css_shutdown
,
715 subsys_initcall(init_channel_subsystem
);
718 css_enqueue_subchannel_slow(struct subchannel_id schid
)
720 struct slow_subchannel
*new_slow_sch
;
723 new_slow_sch
= kzalloc(sizeof(struct slow_subchannel
), GFP_ATOMIC
);
726 new_slow_sch
->schid
= schid
;
727 spin_lock_irqsave(&slow_subchannel_lock
, flags
);
728 list_add_tail(&new_slow_sch
->slow_list
, &slow_subchannels_head
);
729 spin_unlock_irqrestore(&slow_subchannel_lock
, flags
);
734 css_clear_subchannel_slow_list(void)
738 spin_lock_irqsave(&slow_subchannel_lock
, flags
);
739 while (!list_empty(&slow_subchannels_head
)) {
740 struct slow_subchannel
*slow_sch
=
741 list_entry(slow_subchannels_head
.next
,
742 struct slow_subchannel
, slow_list
);
744 list_del_init(slow_subchannels_head
.next
);
747 spin_unlock_irqrestore(&slow_subchannel_lock
, flags
);
753 css_slow_subchannels_exist(void)
755 return (!list_empty(&slow_subchannels_head
));
758 MODULE_LICENSE("GPL");
759 EXPORT_SYMBOL(css_bus_type
);
760 EXPORT_SYMBOL_GPL(css_characteristics_avail
);