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575 lines
13 KiB
575 lines
13 KiB
/*
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* drivers/s390/cio/css.c
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* driver for channel subsystem
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* $Revision: 1.85 $
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*
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* Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
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* IBM Corporation
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* Author(s): Arnd Bergmann (arndb@de.ibm.com)
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* Cornelia Huck (cohuck@de.ibm.com)
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <linux/list.h>
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#include "css.h"
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#include "cio.h"
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#include "cio_debug.h"
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#include "ioasm.h"
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#include "chsc.h"
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unsigned int highest_subchannel;
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int need_rescan = 0;
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int css_init_done = 0;
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struct pgid global_pgid;
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int css_characteristics_avail = 0;
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struct device css_bus_device = {
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.bus_id = "css0",
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};
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static struct subchannel *
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css_alloc_subchannel(int irq)
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{
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struct subchannel *sch;
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int ret;
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sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
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if (sch == NULL)
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return ERR_PTR(-ENOMEM);
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ret = cio_validate_subchannel (sch, irq);
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if (ret < 0) {
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kfree(sch);
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return ERR_PTR(ret);
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}
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if (irq > highest_subchannel)
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highest_subchannel = irq;
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if (sch->st != SUBCHANNEL_TYPE_IO) {
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/* For now we ignore all non-io subchannels. */
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kfree(sch);
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return ERR_PTR(-EINVAL);
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}
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/*
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* Set intparm to subchannel address.
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* This is fine even on 64bit since the subchannel is always located
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* under 2G.
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*/
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sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
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ret = cio_modify(sch);
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if (ret) {
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kfree(sch);
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return ERR_PTR(ret);
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}
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return sch;
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}
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static void
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css_free_subchannel(struct subchannel *sch)
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{
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if (sch) {
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/* Reset intparm to zeroes. */
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sch->schib.pmcw.intparm = 0;
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cio_modify(sch);
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kfree(sch);
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}
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}
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static void
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css_subchannel_release(struct device *dev)
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{
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struct subchannel *sch;
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sch = to_subchannel(dev);
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if (!cio_is_console(sch->irq))
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kfree(sch);
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}
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extern int css_get_ssd_info(struct subchannel *sch);
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static int
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css_register_subchannel(struct subchannel *sch)
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{
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int ret;
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/* Initialize the subchannel structure */
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sch->dev.parent = &css_bus_device;
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sch->dev.bus = &css_bus_type;
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sch->dev.release = &css_subchannel_release;
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/* make it known to the system */
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ret = device_register(&sch->dev);
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if (ret)
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printk (KERN_WARNING "%s: could not register %s\n",
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__func__, sch->dev.bus_id);
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else
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css_get_ssd_info(sch);
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return ret;
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}
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int
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css_probe_device(int irq)
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{
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int ret;
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struct subchannel *sch;
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sch = css_alloc_subchannel(irq);
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if (IS_ERR(sch))
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return PTR_ERR(sch);
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ret = css_register_subchannel(sch);
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if (ret)
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css_free_subchannel(sch);
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return ret;
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}
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struct subchannel *
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get_subchannel_by_schid(int irq)
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{
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struct subchannel *sch;
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struct list_head *entry;
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struct device *dev;
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if (!get_bus(&css_bus_type))
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return NULL;
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down_read(&css_bus_type.subsys.rwsem);
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sch = NULL;
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list_for_each(entry, &css_bus_type.devices.list) {
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dev = get_device(container_of(entry,
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struct device, bus_list));
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if (!dev)
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continue;
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sch = to_subchannel(dev);
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if (sch->irq == irq)
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break;
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put_device(dev);
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sch = NULL;
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}
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up_read(&css_bus_type.subsys.rwsem);
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put_bus(&css_bus_type);
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return sch;
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}
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static inline int
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css_get_subchannel_status(struct subchannel *sch, int schid)
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{
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struct schib schib;
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int cc;
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cc = stsch(schid, &schib);
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if (cc)
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return CIO_GONE;
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if (!schib.pmcw.dnv)
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return CIO_GONE;
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if (sch && sch->schib.pmcw.dnv &&
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(schib.pmcw.dev != sch->schib.pmcw.dev))
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return CIO_REVALIDATE;
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if (sch && !sch->lpm)
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return CIO_NO_PATH;
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return CIO_OPER;
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}
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static int
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css_evaluate_subchannel(int irq, int slow)
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{
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int event, ret, disc;
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struct subchannel *sch;
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unsigned long flags;
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sch = get_subchannel_by_schid(irq);
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disc = sch ? device_is_disconnected(sch) : 0;
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if (disc && slow) {
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if (sch)
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put_device(&sch->dev);
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return 0; /* Already processed. */
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}
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/*
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* We've got a machine check, so running I/O won't get an interrupt.
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* Kill any pending timers.
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*/
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if (sch)
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device_kill_pending_timer(sch);
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if (!disc && !slow) {
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if (sch)
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put_device(&sch->dev);
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return -EAGAIN; /* Will be done on the slow path. */
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}
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event = css_get_subchannel_status(sch, irq);
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CIO_MSG_EVENT(4, "Evaluating schid %04x, event %d, %s, %s path.\n",
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irq, event, sch?(disc?"disconnected":"normal"):"unknown",
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slow?"slow":"fast");
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switch (event) {
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case CIO_NO_PATH:
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case CIO_GONE:
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if (!sch) {
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/* Never used this subchannel. Ignore. */
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ret = 0;
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break;
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}
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if (disc && (event == CIO_NO_PATH)) {
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/*
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* Uargh, hack again. Because we don't get a machine
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* check on configure on, our path bookkeeping can
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* be out of date here (it's fine while we only do
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* logical varying or get chsc machine checks). We
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* need to force reprobing or we might miss devices
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* coming operational again. It won't do harm in real
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* no path situations.
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*/
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spin_lock_irqsave(&sch->lock, flags);
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device_trigger_reprobe(sch);
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spin_unlock_irqrestore(&sch->lock, flags);
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ret = 0;
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break;
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}
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if (sch->driver && sch->driver->notify &&
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sch->driver->notify(&sch->dev, event)) {
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cio_disable_subchannel(sch);
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device_set_disconnected(sch);
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ret = 0;
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break;
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}
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/*
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* Unregister subchannel.
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* The device will be killed automatically.
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*/
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cio_disable_subchannel(sch);
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device_unregister(&sch->dev);
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/* Reset intparm to zeroes. */
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sch->schib.pmcw.intparm = 0;
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cio_modify(sch);
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put_device(&sch->dev);
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ret = 0;
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break;
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case CIO_REVALIDATE:
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/*
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* Revalidation machine check. Sick.
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* We don't notify the driver since we have to throw the device
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* away in any case.
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*/
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if (!disc) {
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device_unregister(&sch->dev);
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/* Reset intparm to zeroes. */
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sch->schib.pmcw.intparm = 0;
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cio_modify(sch);
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put_device(&sch->dev);
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ret = css_probe_device(irq);
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} else {
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/*
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* We can't immediately deregister the disconnected
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* device since it might block.
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*/
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spin_lock_irqsave(&sch->lock, flags);
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device_trigger_reprobe(sch);
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spin_unlock_irqrestore(&sch->lock, flags);
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ret = 0;
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}
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break;
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case CIO_OPER:
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if (disc) {
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spin_lock_irqsave(&sch->lock, flags);
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/* Get device operational again. */
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device_trigger_reprobe(sch);
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spin_unlock_irqrestore(&sch->lock, flags);
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}
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ret = sch ? 0 : css_probe_device(irq);
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break;
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default:
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BUG();
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ret = 0;
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}
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return ret;
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}
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static void
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css_rescan_devices(void)
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{
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int irq, ret;
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for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
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ret = css_evaluate_subchannel(irq, 1);
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/* No more memory. It doesn't make sense to continue. No
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* panic because this can happen in midflight and just
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* because we can't use a new device is no reason to crash
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* the system. */
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if (ret == -ENOMEM)
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break;
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/* -ENXIO indicates that there are no more subchannels. */
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if (ret == -ENXIO)
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break;
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}
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}
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struct slow_subchannel {
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struct list_head slow_list;
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unsigned long schid;
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};
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static LIST_HEAD(slow_subchannels_head);
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static DEFINE_SPINLOCK(slow_subchannel_lock);
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static void
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css_trigger_slow_path(void)
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{
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CIO_TRACE_EVENT(4, "slowpath");
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if (need_rescan) {
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need_rescan = 0;
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css_rescan_devices();
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return;
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}
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spin_lock_irq(&slow_subchannel_lock);
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while (!list_empty(&slow_subchannels_head)) {
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struct slow_subchannel *slow_sch =
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list_entry(slow_subchannels_head.next,
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struct slow_subchannel, slow_list);
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list_del_init(slow_subchannels_head.next);
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spin_unlock_irq(&slow_subchannel_lock);
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css_evaluate_subchannel(slow_sch->schid, 1);
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spin_lock_irq(&slow_subchannel_lock);
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kfree(slow_sch);
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}
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spin_unlock_irq(&slow_subchannel_lock);
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}
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typedef void (*workfunc)(void *);
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DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
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struct workqueue_struct *slow_path_wq;
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/*
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* Rescan for new devices. FIXME: This is slow.
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* This function is called when we have lost CRWs due to overflows and we have
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* to do subchannel housekeeping.
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*/
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void
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css_reiterate_subchannels(void)
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{
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css_clear_subchannel_slow_list();
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need_rescan = 1;
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}
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/*
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* Called from the machine check handler for subchannel report words.
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*/
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int
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css_process_crw(int irq)
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{
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int ret;
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CIO_CRW_EVENT(2, "source is subchannel %04X\n", irq);
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if (need_rescan)
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/* We need to iterate all subchannels anyway. */
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return -EAGAIN;
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/*
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* Since we are always presented with IPI in the CRW, we have to
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* use stsch() to find out if the subchannel in question has come
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* or gone.
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*/
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ret = css_evaluate_subchannel(irq, 0);
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if (ret == -EAGAIN) {
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if (css_enqueue_subchannel_slow(irq)) {
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css_clear_subchannel_slow_list();
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need_rescan = 1;
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}
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}
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return ret;
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}
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static void __init
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css_generate_pgid(void)
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{
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/* Let's build our path group ID here. */
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if (css_characteristics_avail && css_general_characteristics.mcss)
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global_pgid.cpu_addr = 0x8000;
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else {
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#ifdef CONFIG_SMP
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global_pgid.cpu_addr = hard_smp_processor_id();
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#else
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global_pgid.cpu_addr = 0;
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#endif
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}
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global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
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global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
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global_pgid.tod_high = (__u32) (get_clock() >> 32);
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}
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/*
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* Now that the driver core is running, we can setup our channel subsystem.
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* The struct subchannel's are created during probing (except for the
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* static console subchannel).
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*/
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static int __init
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init_channel_subsystem (void)
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{
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int ret, irq;
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if (chsc_determine_css_characteristics() == 0)
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css_characteristics_avail = 1;
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css_generate_pgid();
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if ((ret = bus_register(&css_bus_type)))
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goto out;
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if ((ret = device_register (&css_bus_device)))
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goto out_bus;
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css_init_done = 1;
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ctl_set_bit(6, 28);
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for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
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struct subchannel *sch;
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if (cio_is_console(irq))
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sch = cio_get_console_subchannel();
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else {
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sch = css_alloc_subchannel(irq);
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if (IS_ERR(sch))
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ret = PTR_ERR(sch);
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else
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ret = 0;
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if (ret == -ENOMEM)
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panic("Out of memory in "
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"init_channel_subsystem\n");
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/* -ENXIO: no more subchannels. */
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if (ret == -ENXIO)
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break;
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if (ret)
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continue;
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}
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/*
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* We register ALL valid subchannels in ioinfo, even those
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* that have been present before init_channel_subsystem.
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* These subchannels can't have been registered yet (kmalloc
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* not working) so we do it now. This is true e.g. for the
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* console subchannel.
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*/
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css_register_subchannel(sch);
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}
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return 0;
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out_bus:
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bus_unregister(&css_bus_type);
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out:
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return ret;
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}
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/*
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* find a driver for a subchannel. They identify by the subchannel
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* type with the exception that the console subchannel driver has its own
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* subchannel type although the device is an i/o subchannel
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*/
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static int
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css_bus_match (struct device *dev, struct device_driver *drv)
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{
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struct subchannel *sch = container_of (dev, struct subchannel, dev);
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struct css_driver *driver = container_of (drv, struct css_driver, drv);
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if (sch->st == driver->subchannel_type)
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return 1;
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return 0;
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}
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struct bus_type css_bus_type = {
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.name = "css",
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.match = &css_bus_match,
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};
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subsys_initcall(init_channel_subsystem);
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/*
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* Register root devices for some drivers. The release function must not be
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* in the device drivers, so we do it here.
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*/
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static void
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s390_root_dev_release(struct device *dev)
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{
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kfree(dev);
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}
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struct device *
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s390_root_dev_register(const char *name)
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{
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struct device *dev;
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int ret;
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if (!strlen(name))
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return ERR_PTR(-EINVAL);
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dev = kmalloc(sizeof(struct device), GFP_KERNEL);
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if (!dev)
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return ERR_PTR(-ENOMEM);
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memset(dev, 0, sizeof(struct device));
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strncpy(dev->bus_id, name, min(strlen(name), (size_t)BUS_ID_SIZE));
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dev->release = s390_root_dev_release;
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ret = device_register(dev);
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if (ret) {
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kfree(dev);
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return ERR_PTR(ret);
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}
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return dev;
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}
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void
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s390_root_dev_unregister(struct device *dev)
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{
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if (dev)
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device_unregister(dev);
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}
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int
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css_enqueue_subchannel_slow(unsigned long schid)
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{
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struct slow_subchannel *new_slow_sch;
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unsigned long flags;
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new_slow_sch = kmalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
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if (!new_slow_sch)
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return -ENOMEM;
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memset(new_slow_sch, 0, sizeof(struct slow_subchannel));
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new_slow_sch->schid = schid;
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spin_lock_irqsave(&slow_subchannel_lock, flags);
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list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
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spin_unlock_irqrestore(&slow_subchannel_lock, flags);
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return 0;
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}
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void
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css_clear_subchannel_slow_list(void)
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{
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unsigned long flags;
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spin_lock_irqsave(&slow_subchannel_lock, flags);
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while (!list_empty(&slow_subchannels_head)) {
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struct slow_subchannel *slow_sch =
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list_entry(slow_subchannels_head.next,
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struct slow_subchannel, slow_list);
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list_del_init(slow_subchannels_head.next);
|
|
kfree(slow_sch);
|
|
}
|
|
spin_unlock_irqrestore(&slow_subchannel_lock, flags);
|
|
}
|
|
|
|
|
|
|
|
int
|
|
css_slow_subchannels_exist(void)
|
|
{
|
|
return (!list_empty(&slow_subchannels_head));
|
|
}
|
|
|
|
MODULE_LICENSE("GPL");
|
|
EXPORT_SYMBOL(css_bus_type);
|
|
EXPORT_SYMBOL(s390_root_dev_register);
|
|
EXPORT_SYMBOL(s390_root_dev_unregister);
|
|
EXPORT_SYMBOL_GPL(css_characteristics_avail);
|
|
|