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