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OpenCloudOS-Kernel/drivers/s390/cio/css.c

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/*
* drivers/s390/cio/css.c
* driver for channel subsystem
*
* Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
* IBM Corporation
* Author(s): Arnd Bergmann (arndb@de.ibm.com)
* Cornelia Huck (cornelia.huck@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"
#include "device.h"
int need_rescan = 0;
int css_init_done = 0;
static int need_reprobe = 0;
static int max_ssid = 0;
struct channel_subsystem *css[__MAX_CSSID + 1];
int css_characteristics_avail = 0;
int
for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
{
struct subchannel_id schid;
int ret;
init_subchannel_id(&schid);
ret = -ENODEV;
do {
do {
ret = fn(schid, data);
if (ret)
break;
} while (schid.sch_no++ < __MAX_SUBCHANNEL);
schid.sch_no = 0;
} while (schid.ssid++ < max_ssid);
return ret;
}
static struct subchannel *
css_alloc_subchannel(struct subchannel_id schid)
{
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, schid);
if (ret < 0) {
kfree(sch);
return ERR_PTR(ret);
}
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->lock);
kfree(sch);
}
}
static void
css_subchannel_release(struct device *dev)
{
struct subchannel *sch;
sch = to_subchannel(dev);
if (!cio_is_console(sch->schid)) {
kfree(sch->lock);
kfree(sch);
}
}
int css_sch_device_register(struct subchannel *sch)
{
int ret;
mutex_lock(&sch->reg_mutex);
ret = device_register(&sch->dev);
mutex_unlock(&sch->reg_mutex);
return ret;
}
void css_sch_device_unregister(struct subchannel *sch)
{
mutex_lock(&sch->reg_mutex);
device_unregister(&sch->dev);
mutex_unlock(&sch->reg_mutex);
}
static int
css_register_subchannel(struct subchannel *sch)
{
int ret;
/* Initialize the subchannel structure */
sch->dev.parent = &css[0]->device;
sch->dev.bus = &css_bus_type;
sch->dev.release = &css_subchannel_release;
sch->dev.groups = subch_attr_groups;
css_get_ssd_info(sch);
/* make it known to the system */
ret = css_sch_device_register(sch);
if (ret) {
printk (KERN_WARNING "%s: could not register %s\n",
__func__, sch->dev.bus_id);
return ret;
}
return ret;
}
int
css_probe_device(struct subchannel_id schid)
{
int ret;
struct subchannel *sch;
sch = css_alloc_subchannel(schid);
if (IS_ERR(sch))
return PTR_ERR(sch);
ret = css_register_subchannel(sch);
if (ret)
css_free_subchannel(sch);
return ret;
}
static int
check_subchannel(struct device * dev, void * data)
{
struct subchannel *sch;
struct subchannel_id *schid = data;
sch = to_subchannel(dev);
return schid_equal(&sch->schid, schid);
}
struct subchannel *
get_subchannel_by_schid(struct subchannel_id schid)
{
struct device *dev;
dev = bus_find_device(&css_bus_type, NULL,
&schid, check_subchannel);
return dev ? to_subchannel(dev) : NULL;
}
static int css_get_subchannel_status(struct subchannel *sch)
{
struct schib schib;
if (stsch(sch->schid, &schib) || !schib.pmcw.dnv)
return CIO_GONE;
if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
return CIO_REVALIDATE;
if (!sch->lpm)
return CIO_NO_PATH;
return CIO_OPER;
}
static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
{
int event, ret, disc;
unsigned long flags;
enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action;
spin_lock_irqsave(sch->lock, flags);
disc = device_is_disconnected(sch);
if (disc && slow) {
/* Disconnected devices are evaluated directly only.*/
spin_unlock_irqrestore(sch->lock, flags);
return 0;
}
/* No interrupt after machine check - kill pending timers. */
device_kill_pending_timer(sch);
if (!disc && !slow) {
/* Non-disconnected devices are evaluated on the slow path. */
spin_unlock_irqrestore(sch->lock, flags);
return -EAGAIN;
}
event = css_get_subchannel_status(sch);
CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
sch->schid.ssid, sch->schid.sch_no, event,
disc ? "disconnected" : "normal",
slow ? "slow" : "fast");
/* Analyze subchannel status. */
action = NONE;
switch (event) {
case CIO_NO_PATH:
if (disc) {
/* Check if paths have become available. */
action = REPROBE;
break;
}
/* fall through */
case CIO_GONE:
/* Prevent unwanted effects when opening lock. */
cio_disable_subchannel(sch);
device_set_disconnected(sch);
/* Ask driver what to do with device. */
action = UNREGISTER;
if (sch->driver && sch->driver->notify) {
spin_unlock_irqrestore(sch->lock, flags);
ret = sch->driver->notify(&sch->dev, event);
spin_lock_irqsave(sch->lock, flags);
if (ret)
action = NONE;
}
break;
case CIO_REVALIDATE:
/* Device will be removed, so no notify necessary. */
if (disc)
/* Reprobe because immediate unregister might block. */
action = REPROBE;
else
action = UNREGISTER_PROBE;
break;
case CIO_OPER:
if (disc)
/* Get device operational again. */
action = REPROBE;
break;
}
/* Perform action. */
ret = 0;
switch (action) {
case UNREGISTER:
case UNREGISTER_PROBE:
/* Unregister device (will use subchannel lock). */
spin_unlock_irqrestore(sch->lock, flags);
css_sch_device_unregister(sch);
spin_lock_irqsave(sch->lock, flags);
/* Reset intparm to zeroes. */
sch->schib.pmcw.intparm = 0;
cio_modify(sch);
break;
case REPROBE:
device_trigger_reprobe(sch);
break;
default:
break;
}
spin_unlock_irqrestore(sch->lock, flags);
/* Probe if necessary. */
if (action == UNREGISTER_PROBE)
ret = css_probe_device(sch->schid);
return ret;
}
static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
{
struct schib schib;
if (!slow) {
/* Will be done on the slow path. */
return -EAGAIN;
}
if (stsch_err(schid, &schib) || !schib.pmcw.dnv) {
/* Unusable - ignore. */
return 0;
}
CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
"slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);
return css_probe_device(schid);
}
static int css_evaluate_subchannel(struct subchannel_id schid, int slow)
{
struct subchannel *sch;
int ret;
sch = get_subchannel_by_schid(schid);
if (sch) {
ret = css_evaluate_known_subchannel(sch, slow);
put_device(&sch->dev);
} else
ret = css_evaluate_new_subchannel(schid, slow);
return ret;
}
static int
css_rescan_devices(struct subchannel_id schid, void *data)
{
return css_evaluate_subchannel(schid, 1);
}
struct slow_subchannel {
struct list_head slow_list;
struct subchannel_id schid;
};
static LIST_HEAD(slow_subchannels_head);
static DEFINE_SPINLOCK(slow_subchannel_lock);
static void
css_trigger_slow_path(struct work_struct *unused)
{
CIO_TRACE_EVENT(4, "slowpath");
if (need_rescan) {
need_rescan = 0;
for_each_subchannel(css_rescan_devices, NULL);
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);
}
DECLARE_WORK(slow_path_work, css_trigger_slow_path);
struct workqueue_struct *slow_path_wq;
/* Reprobe subchannel if unregistered. */
static int reprobe_subchannel(struct subchannel_id schid, void *data)
{
struct subchannel *sch;
int ret;
CIO_DEBUG(KERN_INFO, 6, "cio: reprobe 0.%x.%04x\n",
schid.ssid, schid.sch_no);
if (need_reprobe)
return -EAGAIN;
sch = get_subchannel_by_schid(schid);
if (sch) {
/* Already known. */
put_device(&sch->dev);
return 0;
}
ret = css_probe_device(schid);
switch (ret) {
case 0:
break;
case -ENXIO:
case -ENOMEM:
/* These should abort looping */
break;
default:
ret = 0;
}
return ret;
}
/* Work function used to reprobe all unregistered subchannels. */
static void reprobe_all(struct work_struct *unused)
{
int ret;
CIO_MSG_EVENT(2, "reprobe start\n");
need_reprobe = 0;
/* Make sure initial subchannel scan is done. */
wait_event(ccw_device_init_wq,
atomic_read(&ccw_device_init_count) == 0);
ret = for_each_subchannel(reprobe_subchannel, NULL);
CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
need_reprobe);
}
static DECLARE_WORK(css_reprobe_work, reprobe_all);
/* Schedule reprobing of all unregistered subchannels. */
void css_schedule_reprobe(void)
{
need_reprobe = 1;
queue_work(ccw_device_work, &css_reprobe_work);
}
EXPORT_SYMBOL_GPL(css_schedule_reprobe);
/*
* 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 rsid1, int rsid2)
{
int ret;
struct subchannel_id mchk_schid;
CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
rsid1, rsid2);
if (need_rescan)
/* We need to iterate all subchannels anyway. */
return -EAGAIN;
init_subchannel_id(&mchk_schid);
mchk_schid.sch_no = rsid1;
if (rsid2 != 0)
mchk_schid.ssid = (rsid2 >> 8) & 3;
/*
* 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(mchk_schid, 0);
if (ret == -EAGAIN) {
if (css_enqueue_subchannel_slow(mchk_schid)) {
css_clear_subchannel_slow_list();
need_rescan = 1;
}
}
return ret;
}
static int __init
__init_channel_subsystem(struct subchannel_id schid, void *data)
{
struct subchannel *sch;
int ret;
if (cio_is_console(schid))
sch = cio_get_console_subchannel();
else {
sch = css_alloc_subchannel(schid);
if (IS_ERR(sch))
ret = PTR_ERR(sch);
else
ret = 0;
switch (ret) {
case 0:
break;
case -ENOMEM:
panic("Out of memory in init_channel_subsystem\n");
/* -ENXIO: no more subchannels. */
case -ENXIO:
return ret;
/* -EIO: this subchannel set not supported. */
case -EIO:
return ret;
default:
return 0;
}
}
/*
* 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;
}
static void __init
css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
{
if (css_characteristics_avail && css_general_characteristics.mcss) {
css->global_pgid.pgid_high.ext_cssid.version = 0x80;
css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
} else {
#ifdef CONFIG_SMP
css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
#else
css->global_pgid.pgid_high.cpu_addr = 0;
#endif
}
css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
css->global_pgid.tod_high = tod_high;
}
static void
channel_subsystem_release(struct device *dev)
{
struct channel_subsystem *css;
css = to_css(dev);
mutex_destroy(&css->mutex);
kfree(css);
}
static ssize_t
css_cm_enable_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct channel_subsystem *css = to_css(dev);
if (!css)
return 0;
return sprintf(buf, "%x\n", css->cm_enabled);
}
static ssize_t
css_cm_enable_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct channel_subsystem *css = to_css(dev);
int ret;
switch (buf[0]) {
case '0':
ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
break;
case '1':
ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
break;
default:
ret = -EINVAL;
}
return ret < 0 ? ret : count;
}
static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
static int __init setup_css(int nr)
{
u32 tod_high;
int ret;
memset(css[nr], 0, sizeof(struct channel_subsystem));
css[nr]->pseudo_subchannel =
kzalloc(sizeof(*css[nr]->pseudo_subchannel), GFP_KERNEL);
if (!css[nr]->pseudo_subchannel)
return -ENOMEM;
css[nr]->pseudo_subchannel->dev.parent = &css[nr]->device;
css[nr]->pseudo_subchannel->dev.release = css_subchannel_release;
sprintf(css[nr]->pseudo_subchannel->dev.bus_id, "defunct");
ret = cio_create_sch_lock(css[nr]->pseudo_subchannel);
if (ret) {
kfree(css[nr]->pseudo_subchannel);
return ret;
}
mutex_init(&css[nr]->mutex);
css[nr]->valid = 1;
css[nr]->cssid = nr;
sprintf(css[nr]->device.bus_id, "css%x", nr);
css[nr]->device.release = channel_subsystem_release;
tod_high = (u32) (get_clock() >> 32);
css_generate_pgid(css[nr], tod_high);
return 0;
}
/*
* 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, i;
if (chsc_determine_css_characteristics() == 0)
css_characteristics_avail = 1;
if ((ret = bus_register(&css_bus_type)))
goto out;
/* Try to enable MSS. */
ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
switch (ret) {
case 0: /* Success. */
max_ssid = __MAX_SSID;
break;
case -ENOMEM:
goto out_bus;
default:
max_ssid = 0;
}
/* Setup css structure. */
for (i = 0; i <= __MAX_CSSID; i++) {
css[i] = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
if (!css[i]) {
ret = -ENOMEM;
goto out_unregister;
}
ret = setup_css(i);
if (ret)
goto out_free;
ret = device_register(&css[i]->device);
if (ret)
goto out_free_all;
if (css_characteristics_avail &&
css_chsc_characteristics.secm) {
ret = device_create_file(&css[i]->device,
&dev_attr_cm_enable);
if (ret)
goto out_device;
}
ret = device_register(&css[i]->pseudo_subchannel->dev);
if (ret)
goto out_file;
}
css_init_done = 1;
ctl_set_bit(6, 28);
for_each_subchannel(__init_channel_subsystem, NULL);
return 0;
out_file:
device_remove_file(&css[i]->device, &dev_attr_cm_enable);
out_device:
device_unregister(&css[i]->device);
out_free_all:
kfree(css[i]->pseudo_subchannel->lock);
kfree(css[i]->pseudo_subchannel);
out_free:
kfree(css[i]);
out_unregister:
while (i > 0) {
i--;
device_unregister(&css[i]->pseudo_subchannel->dev);
if (css_characteristics_avail && css_chsc_characteristics.secm)
device_remove_file(&css[i]->device,
&dev_attr_cm_enable);
device_unregister(&css[i]->device);
}
out_bus:
bus_unregister(&css_bus_type);
out:
return ret;
}
int sch_is_pseudo_sch(struct subchannel *sch)
{
return sch == to_css(sch->dev.parent)->pseudo_subchannel;
}
/*
* 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;
}
static int
css_probe (struct device *dev)
{
struct subchannel *sch;
sch = to_subchannel(dev);
sch->driver = container_of (dev->driver, struct css_driver, drv);
return (sch->driver->probe ? sch->driver->probe(sch) : 0);
}
static int
css_remove (struct device *dev)
{
struct subchannel *sch;
sch = to_subchannel(dev);
return (sch->driver->remove ? sch->driver->remove(sch) : 0);
}
static void
css_shutdown (struct device *dev)
{
struct subchannel *sch;
sch = to_subchannel(dev);
if (sch->driver->shutdown)
sch->driver->shutdown(sch);
}
struct bus_type css_bus_type = {
.name = "css",
.match = css_bus_match,
.probe = css_probe,
.remove = css_remove,
.shutdown = css_shutdown,
};
subsys_initcall(init_channel_subsystem);
int
css_enqueue_subchannel_slow(struct subchannel_id schid)
{
struct slow_subchannel *new_slow_sch;
unsigned long flags;
new_slow_sch = kzalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
if (!new_slow_sch)
return -ENOMEM;
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_GPL(css_characteristics_avail);
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