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"
25 int css_init_done = 0;
26 static int max_ssid = 0;
28 struct channel_subsystem *css[__MAX_CSSID + 1];
30 int css_characteristics_avail = 0;
33 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
35 struct subchannel_id schid;
38 init_subchannel_id(&schid);
42 ret = fn(schid, data);
45 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
47 } while (schid.ssid++ < max_ssid);
51 static struct subchannel *
52 css_alloc_subchannel(struct subchannel_id schid)
54 struct subchannel *sch;
57 sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
59 return ERR_PTR(-ENOMEM);
60 ret = cio_validate_subchannel (sch, schid);
66 if (sch->st != SUBCHANNEL_TYPE_IO) {
67 /* For now we ignore all non-io subchannels. */
69 return ERR_PTR(-EINVAL);
73 * Set intparm to subchannel address.
74 * This is fine even on 64bit since the subchannel is always located
77 sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
78 ret = cio_modify(sch);
87 css_free_subchannel(struct subchannel *sch)
90 /* Reset intparm to zeroes. */
91 sch->schib.pmcw.intparm = 0;
99 css_subchannel_release(struct device *dev)
101 struct subchannel *sch;
103 sch = to_subchannel(dev);
104 if (!cio_is_console(sch->schid))
108 extern int css_get_ssd_info(struct subchannel *sch);
111 css_register_subchannel(struct subchannel *sch)
115 /* Initialize the subchannel structure */
116 sch->dev.parent = &css[0]->device;
117 sch->dev.bus = &css_bus_type;
118 sch->dev.release = &css_subchannel_release;
120 /* make it known to the system */
121 ret = device_register(&sch->dev);
123 printk (KERN_WARNING "%s: could not register %s\n",
124 __func__, sch->dev.bus_id);
126 css_get_ssd_info(sch);
131 css_probe_device(struct subchannel_id schid)
134 struct subchannel *sch;
136 sch = css_alloc_subchannel(schid);
139 ret = css_register_subchannel(sch);
141 css_free_subchannel(sch);
146 check_subchannel(struct device * dev, void * data)
148 struct subchannel *sch;
149 struct subchannel_id *schid = data;
151 sch = to_subchannel(dev);
152 return schid_equal(&sch->schid, schid);
156 get_subchannel_by_schid(struct subchannel_id schid)
160 dev = bus_find_device(&css_bus_type, NULL,
161 (void *)&schid, check_subchannel);
163 return dev ? to_subchannel(dev) : NULL;
168 css_get_subchannel_status(struct subchannel *sch, struct subchannel_id schid)
173 cc = stsch(schid, &schib);
178 if (sch && sch->schib.pmcw.dnv &&
179 (schib.pmcw.dev != sch->schib.pmcw.dev))
180 return CIO_REVALIDATE;
181 if (sch && !sch->lpm)
187 css_evaluate_subchannel(struct subchannel_id schid, int slow)
189 int event, ret, disc;
190 struct subchannel *sch;
193 sch = get_subchannel_by_schid(schid);
194 disc = sch ? device_is_disconnected(sch) : 0;
197 put_device(&sch->dev);
198 return 0; /* Already processed. */
201 * We've got a machine check, so running I/O won't get an interrupt.
202 * Kill any pending timers.
205 device_kill_pending_timer(sch);
206 if (!disc && !slow) {
208 put_device(&sch->dev);
209 return -EAGAIN; /* Will be done on the slow path. */
211 event = css_get_subchannel_status(sch, schid);
212 CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
213 schid.ssid, schid.sch_no, event,
214 sch?(disc?"disconnected":"normal"):"unknown",
220 /* Never used this subchannel. Ignore. */
224 if (disc && (event == CIO_NO_PATH)) {
226 * Uargh, hack again. Because we don't get a machine
227 * check on configure on, our path bookkeeping can
228 * be out of date here (it's fine while we only do
229 * logical varying or get chsc machine checks). We
230 * need to force reprobing or we might miss devices
231 * coming operational again. It won't do harm in real
232 * no path situations.
234 spin_lock_irqsave(&sch->lock, flags);
235 device_trigger_reprobe(sch);
236 spin_unlock_irqrestore(&sch->lock, flags);
240 if (sch->driver && sch->driver->notify &&
241 sch->driver->notify(&sch->dev, event)) {
242 cio_disable_subchannel(sch);
243 device_set_disconnected(sch);
248 * Unregister subchannel.
249 * The device will be killed automatically.
251 cio_disable_subchannel(sch);
252 device_unregister(&sch->dev);
253 /* Reset intparm to zeroes. */
254 sch->schib.pmcw.intparm = 0;
256 put_device(&sch->dev);
261 * Revalidation machine check. Sick.
262 * We don't notify the driver since we have to throw the device
266 device_unregister(&sch->dev);
267 /* Reset intparm to zeroes. */
268 sch->schib.pmcw.intparm = 0;
270 put_device(&sch->dev);
271 ret = css_probe_device(schid);
274 * We can't immediately deregister the disconnected
275 * device since it might block.
277 spin_lock_irqsave(&sch->lock, flags);
278 device_trigger_reprobe(sch);
279 spin_unlock_irqrestore(&sch->lock, flags);
285 spin_lock_irqsave(&sch->lock, flags);
286 /* Get device operational again. */
287 device_trigger_reprobe(sch);
288 spin_unlock_irqrestore(&sch->lock, flags);
290 ret = sch ? 0 : css_probe_device(schid);
300 css_rescan_devices(struct subchannel_id schid, void *data)
302 return css_evaluate_subchannel(schid, 1);
305 struct slow_subchannel {
306 struct list_head slow_list;
307 struct subchannel_id schid;
310 static LIST_HEAD(slow_subchannels_head);
311 static DEFINE_SPINLOCK(slow_subchannel_lock);
314 css_trigger_slow_path(void)
316 CIO_TRACE_EVENT(4, "slowpath");
320 for_each_subchannel(css_rescan_devices, NULL);
324 spin_lock_irq(&slow_subchannel_lock);
325 while (!list_empty(&slow_subchannels_head)) {
326 struct slow_subchannel *slow_sch =
327 list_entry(slow_subchannels_head.next,
328 struct slow_subchannel, slow_list);
330 list_del_init(slow_subchannels_head.next);
331 spin_unlock_irq(&slow_subchannel_lock);
332 css_evaluate_subchannel(slow_sch->schid, 1);
333 spin_lock_irq(&slow_subchannel_lock);
336 spin_unlock_irq(&slow_subchannel_lock);
339 typedef void (*workfunc)(void *);
340 DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
341 struct workqueue_struct *slow_path_wq;
344 * Rescan for new devices. FIXME: This is slow.
345 * This function is called when we have lost CRWs due to overflows and we have
346 * to do subchannel housekeeping.
349 css_reiterate_subchannels(void)
351 css_clear_subchannel_slow_list();
356 * Called from the machine check handler for subchannel report words.
359 css_process_crw(int rsid1, int rsid2)
362 struct subchannel_id mchk_schid;
364 CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
368 /* We need to iterate all subchannels anyway. */
371 init_subchannel_id(&mchk_schid);
372 mchk_schid.sch_no = rsid1;
374 mchk_schid.ssid = (rsid2 >> 8) & 3;
377 * Since we are always presented with IPI in the CRW, we have to
378 * use stsch() to find out if the subchannel in question has come
381 ret = css_evaluate_subchannel(mchk_schid, 0);
382 if (ret == -EAGAIN) {
383 if (css_enqueue_subchannel_slow(mchk_schid)) {
384 css_clear_subchannel_slow_list();
392 __init_channel_subsystem(struct subchannel_id schid, void *data)
394 struct subchannel *sch;
397 if (cio_is_console(schid))
398 sch = cio_get_console_subchannel();
400 sch = css_alloc_subchannel(schid);
409 panic("Out of memory in init_channel_subsystem\n");
410 /* -ENXIO: no more subchannels. */
418 * We register ALL valid subchannels in ioinfo, even those
419 * that have been present before init_channel_subsystem.
420 * These subchannels can't have been registered yet (kmalloc
421 * not working) so we do it now. This is true e.g. for the
422 * console subchannel.
424 css_register_subchannel(sch);
429 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
431 if (css_characteristics_avail && css_general_characteristics.mcss) {
432 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
433 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
436 css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
438 css->global_pgid.pgid_high.cpu_addr = 0;
441 css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
442 css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
443 css->global_pgid.tod_high = tod_high;
448 channel_subsystem_release(struct device *dev)
450 struct channel_subsystem *css;
456 static inline void __init
461 memset(css[nr], 0, sizeof(struct channel_subsystem));
464 sprintf(css[nr]->device.bus_id, "css%x", nr);
465 css[nr]->device.release = channel_subsystem_release;
466 tod_high = (u32) (get_clock() >> 32);
467 css_generate_pgid(css[nr], tod_high);
471 * Now that the driver core is running, we can setup our channel subsystem.
472 * The struct subchannel's are created during probing (except for the
473 * static console subchannel).
476 init_channel_subsystem (void)
480 if (chsc_determine_css_characteristics() == 0)
481 css_characteristics_avail = 1;
483 if ((ret = bus_register(&css_bus_type)))
486 /* Try to enable MSS. */
487 ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
489 case 0: /* Success. */
490 max_ssid = __MAX_SSID;
497 /* Setup css structure. */
498 for (i = 0; i <= __MAX_CSSID; i++) {
499 css[i] = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
505 ret = device_register(&css[i]->device);
513 for_each_subchannel(__init_channel_subsystem, NULL);
520 device_unregister(&css[i]->device);
523 bus_unregister(&css_bus_type);
529 * find a driver for a subchannel. They identify by the subchannel
530 * type with the exception that the console subchannel driver has its own
531 * subchannel type although the device is an i/o subchannel
534 css_bus_match (struct device *dev, struct device_driver *drv)
536 struct subchannel *sch = container_of (dev, struct subchannel, dev);
537 struct css_driver *driver = container_of (drv, struct css_driver, drv);
539 if (sch->st == driver->subchannel_type)
545 struct bus_type css_bus_type = {
547 .match = &css_bus_match,
550 subsys_initcall(init_channel_subsystem);
553 css_enqueue_subchannel_slow(struct subchannel_id schid)
555 struct slow_subchannel *new_slow_sch;
558 new_slow_sch = kmalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
561 memset(new_slow_sch, 0, sizeof(struct slow_subchannel));
562 new_slow_sch->schid = schid;
563 spin_lock_irqsave(&slow_subchannel_lock, flags);
564 list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
565 spin_unlock_irqrestore(&slow_subchannel_lock, flags);
570 css_clear_subchannel_slow_list(void)
574 spin_lock_irqsave(&slow_subchannel_lock, flags);
575 while (!list_empty(&slow_subchannels_head)) {
576 struct slow_subchannel *slow_sch =
577 list_entry(slow_subchannels_head.next,
578 struct slow_subchannel, slow_list);
580 list_del_init(slow_subchannels_head.next);
583 spin_unlock_irqrestore(&slow_subchannel_lock, flags);
589 css_slow_subchannels_exist(void)
591 return (!list_empty(&slow_subchannels_head));
594 MODULE_LICENSE("GPL");
595 EXPORT_SYMBOL(css_bus_type);
596 EXPORT_SYMBOL_GPL(css_characteristics_avail);