2 * drivers/s390/cio/css.c
3 * driver for channel subsystem
6 * Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
8 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
9 * Cornelia Huck (cohuck@de.ibm.com)
11 #include <linux/module.h>
12 #include <linux/init.h>
13 #include <linux/device.h>
14 #include <linux/slab.h>
15 #include <linux/errno.h>
16 #include <linux/list.h>
20 #include "cio_debug.h"
24 unsigned int highest_subchannel;
26 int css_init_done = 0;
28 struct pgid global_pgid;
29 int css_characteristics_avail = 0;
31 struct device css_bus_device = {
35 static struct subchannel *
36 css_alloc_subchannel(int irq)
38 struct subchannel *sch;
41 sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
43 return ERR_PTR(-ENOMEM);
44 ret = cio_validate_subchannel (sch, irq);
49 if (irq > highest_subchannel)
50 highest_subchannel = irq;
52 if (sch->st != SUBCHANNEL_TYPE_IO) {
53 /* For now we ignore all non-io subchannels. */
55 return ERR_PTR(-EINVAL);
59 * Set intparm to subchannel address.
60 * This is fine even on 64bit since the subchannel is always located
63 sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
64 ret = cio_modify(sch);
73 css_free_subchannel(struct subchannel *sch)
76 /* Reset intparm to zeroes. */
77 sch->schib.pmcw.intparm = 0;
85 css_subchannel_release(struct device *dev)
87 struct subchannel *sch;
89 sch = to_subchannel(dev);
90 if (!cio_is_console(sch->irq))
94 extern int css_get_ssd_info(struct subchannel *sch);
97 css_register_subchannel(struct subchannel *sch)
101 /* Initialize the subchannel structure */
102 sch->dev.parent = &css_bus_device;
103 sch->dev.bus = &css_bus_type;
104 sch->dev.release = &css_subchannel_release;
106 /* make it known to the system */
107 ret = device_register(&sch->dev);
109 printk (KERN_WARNING "%s: could not register %s\n",
110 __func__, sch->dev.bus_id);
112 css_get_ssd_info(sch);
117 css_probe_device(int irq)
120 struct subchannel *sch;
122 sch = css_alloc_subchannel(irq);
125 ret = css_register_subchannel(sch);
127 css_free_subchannel(sch);
132 get_subchannel_by_schid(int irq)
134 struct subchannel *sch;
135 struct list_head *entry;
138 if (!get_bus(&css_bus_type))
140 down_read(&css_bus_type.subsys.rwsem);
142 list_for_each(entry, &css_bus_type.devices.list) {
143 dev = get_device(container_of(entry,
144 struct device, bus_list));
147 sch = to_subchannel(dev);
153 up_read(&css_bus_type.subsys.rwsem);
154 put_bus(&css_bus_type);
160 css_get_subchannel_status(struct subchannel *sch, int schid)
165 cc = stsch(schid, &schib);
170 if (sch && sch->schib.pmcw.dnv &&
171 (schib.pmcw.dev != sch->schib.pmcw.dev))
172 return CIO_REVALIDATE;
173 if (sch && !sch->lpm)
179 css_evaluate_subchannel(int irq, int slow)
181 int event, ret, disc;
182 struct subchannel *sch;
184 sch = get_subchannel_by_schid(irq);
185 disc = sch ? device_is_disconnected(sch) : 0;
188 put_device(&sch->dev);
189 return 0; /* Already processed. */
192 * We've got a machine check, so running I/O won't get an interrupt.
193 * Kill any pending timers.
196 device_kill_pending_timer(sch);
197 if (!disc && !slow) {
199 put_device(&sch->dev);
200 return -EAGAIN; /* Will be done on the slow path. */
202 event = css_get_subchannel_status(sch, irq);
203 CIO_MSG_EVENT(4, "Evaluating schid %04x, event %d, %s, %s path.\n",
204 irq, event, sch?(disc?"disconnected":"normal"):"unknown",
210 /* Never used this subchannel. Ignore. */
214 if (disc && (event == CIO_NO_PATH)) {
216 * Uargh, hack again. Because we don't get a machine
217 * check on configure on, our path bookkeeping can
218 * be out of date here (it's fine while we only do
219 * logical varying or get chsc machine checks). We
220 * need to force reprobing or we might miss devices
221 * coming operational again. It won't do harm in real
222 * no path situations.
224 device_trigger_reprobe(sch);
228 if (sch->driver && sch->driver->notify &&
229 sch->driver->notify(&sch->dev, event)) {
230 cio_disable_subchannel(sch);
231 device_set_disconnected(sch);
236 * Unregister subchannel.
237 * The device will be killed automatically.
239 cio_disable_subchannel(sch);
240 device_unregister(&sch->dev);
241 /* Reset intparm to zeroes. */
242 sch->schib.pmcw.intparm = 0;
244 put_device(&sch->dev);
249 * Revalidation machine check. Sick.
250 * We don't notify the driver since we have to throw the device
254 device_unregister(&sch->dev);
255 /* Reset intparm to zeroes. */
256 sch->schib.pmcw.intparm = 0;
258 put_device(&sch->dev);
259 ret = css_probe_device(irq);
262 * We can't immediately deregister the disconnected
263 * device since it might block.
265 device_trigger_reprobe(sch);
271 /* Get device operational again. */
272 device_trigger_reprobe(sch);
273 ret = sch ? 0 : css_probe_device(irq);
283 css_rescan_devices(void)
287 for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
288 ret = css_evaluate_subchannel(irq, 1);
289 /* No more memory. It doesn't make sense to continue. No
290 * panic because this can happen in midflight and just
291 * because we can't use a new device is no reason to crash
295 /* -ENXIO indicates that there are no more subchannels. */
301 struct slow_subchannel {
302 struct list_head slow_list;
306 static LIST_HEAD(slow_subchannels_head);
307 static spinlock_t slow_subchannel_lock = SPIN_LOCK_UNLOCKED;
310 css_trigger_slow_path(void)
312 CIO_TRACE_EVENT(4, "slowpath");
316 css_rescan_devices();
320 spin_lock_irq(&slow_subchannel_lock);
321 while (!list_empty(&slow_subchannels_head)) {
322 struct slow_subchannel *slow_sch =
323 list_entry(slow_subchannels_head.next,
324 struct slow_subchannel, slow_list);
326 list_del_init(slow_subchannels_head.next);
327 spin_unlock_irq(&slow_subchannel_lock);
328 css_evaluate_subchannel(slow_sch->schid, 1);
329 spin_lock_irq(&slow_subchannel_lock);
332 spin_unlock_irq(&slow_subchannel_lock);
335 typedef void (*workfunc)(void *);
336 DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
337 struct workqueue_struct *slow_path_wq;
340 * Rescan for new devices. FIXME: This is slow.
341 * This function is called when we have lost CRWs due to overflows and we have
342 * to do subchannel housekeeping.
345 css_reiterate_subchannels(void)
347 css_clear_subchannel_slow_list();
352 * Called from the machine check handler for subchannel report words.
355 css_process_crw(int irq)
359 CIO_CRW_EVENT(2, "source is subchannel %04X\n", irq);
362 /* We need to iterate all subchannels anyway. */
365 * Since we are always presented with IPI in the CRW, we have to
366 * use stsch() to find out if the subchannel in question has come
369 ret = css_evaluate_subchannel(irq, 0);
370 if (ret == -EAGAIN) {
371 if (css_enqueue_subchannel_slow(irq)) {
372 css_clear_subchannel_slow_list();
380 css_generate_pgid(void)
382 /* Let's build our path group ID here. */
383 if (css_characteristics_avail && css_general_characteristics.mcss)
384 global_pgid.cpu_addr = 0x8000;
387 global_pgid.cpu_addr = hard_smp_processor_id();
389 global_pgid.cpu_addr = 0;
392 global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
393 global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
394 global_pgid.tod_high = (__u32) (get_clock() >> 32);
398 * Now that the driver core is running, we can setup our channel subsystem.
399 * The struct subchannel's are created during probing (except for the
400 * static console subchannel).
403 init_channel_subsystem (void)
407 if (chsc_determine_css_characteristics() == 0)
408 css_characteristics_avail = 1;
412 if ((ret = bus_register(&css_bus_type)))
414 if ((ret = device_register (&css_bus_device)))
421 for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
422 struct subchannel *sch;
424 if (cio_is_console(irq))
425 sch = cio_get_console_subchannel();
427 sch = css_alloc_subchannel(irq);
433 panic("Out of memory in "
434 "init_channel_subsystem\n");
435 /* -ENXIO: no more subchannels. */
442 * We register ALL valid subchannels in ioinfo, even those
443 * that have been present before init_channel_subsystem.
444 * These subchannels can't have been registered yet (kmalloc
445 * not working) so we do it now. This is true e.g. for the
446 * console subchannel.
448 css_register_subchannel(sch);
453 bus_unregister(&css_bus_type);
459 * find a driver for a subchannel. They identify by the subchannel
460 * type with the exception that the console subchannel driver has its own
461 * subchannel type although the device is an i/o subchannel
464 css_bus_match (struct device *dev, struct device_driver *drv)
466 struct subchannel *sch = container_of (dev, struct subchannel, dev);
467 struct css_driver *driver = container_of (drv, struct css_driver, drv);
469 if (sch->st == driver->subchannel_type)
475 struct bus_type css_bus_type = {
477 .match = &css_bus_match,
480 subsys_initcall(init_channel_subsystem);
483 * Register root devices for some drivers. The release function must not be
484 * in the device drivers, so we do it here.
487 s390_root_dev_release(struct device *dev)
493 s390_root_dev_register(const char *name)
499 return ERR_PTR(-EINVAL);
500 dev = kmalloc(sizeof(struct device), GFP_KERNEL);
502 return ERR_PTR(-ENOMEM);
503 memset(dev, 0, sizeof(struct device));
504 strncpy(dev->bus_id, name, min(strlen(name), (size_t)BUS_ID_SIZE));
505 dev->release = s390_root_dev_release;
506 ret = device_register(dev);
515 s390_root_dev_unregister(struct device *dev)
518 device_unregister(dev);
522 css_enqueue_subchannel_slow(unsigned long schid)
524 struct slow_subchannel *new_slow_sch;
527 new_slow_sch = kmalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
530 memset(new_slow_sch, sizeof(struct slow_subchannel), 0);
531 new_slow_sch->schid = schid;
532 spin_lock_irqsave(&slow_subchannel_lock, flags);
533 list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
534 spin_unlock_irqrestore(&slow_subchannel_lock, flags);
539 css_clear_subchannel_slow_list(void)
543 spin_lock_irqsave(&slow_subchannel_lock, flags);
544 while (!list_empty(&slow_subchannels_head)) {
545 struct slow_subchannel *slow_sch =
546 list_entry(slow_subchannels_head.next,
547 struct slow_subchannel, slow_list);
549 list_del_init(slow_subchannels_head.next);
552 spin_unlock_irqrestore(&slow_subchannel_lock, flags);
558 css_slow_subchannels_exist(void)
560 return (!list_empty(&slow_subchannels_head));
563 MODULE_LICENSE("GPL");
564 EXPORT_SYMBOL(css_bus_type);
565 EXPORT_SYMBOL(s390_root_dev_register);
566 EXPORT_SYMBOL(s390_root_dev_unregister);
567 EXPORT_SYMBOL_GPL(css_characteristics_avail);