[S390] cio: Channel-path configure function.

Add a new attribute to the channel-path sysfs directory through which
channel-path configure operations can be triggered. Also listen for
hardware events requesting channel-path configure operations and
process them accordingly.

Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 249 insertions, 1 deletions

diff --git a/drivers/s390/cio/chp.c b/drivers/s390/cio/chp.c
index 8a5839147f8a..0e92c8c89860 100644
--- a/drivers/s390/cio/chp.c
+++ b/drivers/s390/cio/chp.c
@@ -10,9 +10,14 @@
 #include <linux/bug.h>
 #include <linux/workqueue.h>
 #include <linux/spinlock.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/wait.h>
+#include <linux/mutex.h>
 #include <asm/errno.h>
+#include <asm/chpid.h>
+#include <asm/sclp.h>
 
-#include "chpid.h"
 #include "cio.h"
 #include "css.h"
 #include "ioasm.h"
@@ -20,6 +25,32 @@
 #include "chp.h"
 
 #define to_channelpath(device) container_of(device, struct channel_path, dev)
+#define CHP_INFO_UPDATE_INTERVAL        1*HZ
+
+enum cfg_task_t {
+        cfg_none,
+        cfg_configure,
+        cfg_deconfigure
+};
+
+/* Map for pending configure tasks. */
+static enum cfg_task_t chp_cfg_task[__MAX_CSSID + 1][__MAX_CHPID + 1];
+static DEFINE_MUTEX(cfg_lock);
+static int cfg_busy;
+
+/* Map for channel-path status. */
+static struct sclp_chp_info chp_info;
+static DEFINE_MUTEX(info_lock);
+
+/* Time after which channel-path status may be outdated. */
+static unsigned long chp_info_expires;
+
+/* Workqueue to perform pending configure tasks. */
+static struct workqueue_struct *chp_wq;
+static struct work_struct cfg_work;
+
+/* Wait queue for configure completion events. */
+static wait_queue_head_t cfg_wait_queue;
 
 /* Return channel_path struct for given chpid. */
 static inline struct channel_path *chpid_to_chp(struct chp_id chpid)
@@ -251,6 +282,43 @@ static ssize_t chp_status_write(struct device *dev,
 
 static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);
 
+static ssize_t chp_configure_show(struct device *dev,
+                                  struct device_attribute *attr, char *buf)
+{
+        struct channel_path *cp;
+        int status;
+
+        cp = container_of(dev, struct channel_path, dev);
+        status = chp_info_get_status(cp->chpid);
+        if (status < 0)
+                return status;
+
+        return snprintf(buf, PAGE_SIZE, "%d\n", status);
+}
+
+static int cfg_wait_idle(void);
+
+static ssize_t chp_configure_write(struct device *dev,
+                                   struct device_attribute *attr,
+                                   const char *buf, size_t count)
+{
+        struct channel_path *cp;
+        int val;
+        char delim;
+
+        if (sscanf(buf, "%d %c", &val, &delim) != 1)
+                return -EINVAL;
+        if (val != 0 && val != 1)
+                return -EINVAL;
+        cp = container_of(dev, struct channel_path, dev);
+        chp_cfg_schedule(cp->chpid, val);
+        cfg_wait_idle();
+
+        return count;
+}
+
+static DEVICE_ATTR(configure, 0644, chp_configure_show, chp_configure_write);
+
 static ssize_t chp_type_show(struct device *dev, struct device_attribute *attr,
                              char *buf)
 {
@@ -293,6 +361,7 @@ static DEVICE_ATTR(shared, 0444, chp_shared_show, NULL);
 
 static struct attribute * chp_attrs[] = {
         &dev_attr_status.attr,
+        &dev_attr_configure.attr,
         &dev_attr_type.attr,
         &dev_attr_cmg.attr,
         &dev_attr_shared.attr,
@@ -323,6 +392,8 @@ int chp_new(struct chp_id chpid)
         struct channel_path *chp;
         int ret;
 
+        if (chp_is_registered(chpid))
+                return 0;
         chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
         if (!chp)
                 return -ENOMEM;
@@ -435,3 +506,180 @@ int chp_process_crw(int id, int status)
                 return 0;
         }
 }
+
+static inline int info_bit_num(struct chp_id id)
+{
+        return id.id + id.cssid * (__MAX_CHPID + 1);
+}
+
+/* Force chp_info refresh on next call to info_validate(). */
+static void info_expire(void)
+{
+        mutex_lock(&info_lock);
+        chp_info_expires = jiffies - 1;
+        mutex_unlock(&info_lock);
+}
+
+/* Ensure that chp_info is up-to-date. */
+static int info_update(void)
+{
+        int rc;
+
+        mutex_lock(&info_lock);
+        rc = 0;
+        if (time_after(jiffies, chp_info_expires)) {
+                /* Data is too old, update. */
+                rc = sclp_chp_read_info(&chp_info);
+                chp_info_expires = jiffies + CHP_INFO_UPDATE_INTERVAL ;
+        }
+        mutex_unlock(&info_lock);
+
+        return rc;
+}
+
+/**
+ * chp_info_get_status - retrieve configure status of a channel-path
+ * @chpid: channel-path ID
+ *
+ * On success, return 0 for standby, 1 for configured, 2 for reserved,
+ * 3 for not recognized. Return negative error code on error.
+ */
+int chp_info_get_status(struct chp_id chpid)
+{
+        int rc;
+        int bit;
+
+        rc = info_update();
+        if (rc)
+                return rc;
+
+        bit = info_bit_num(chpid);
+        mutex_lock(&info_lock);
+        if (!chp_test_bit(chp_info.recognized, bit))
+                rc = CHP_STATUS_NOT_RECOGNIZED;
+        else if (chp_test_bit(chp_info.configured, bit))
+                rc = CHP_STATUS_CONFIGURED;
+        else if (chp_test_bit(chp_info.standby, bit))
+                rc = CHP_STATUS_STANDBY;
+        else
+                rc = CHP_STATUS_RESERVED;
+        mutex_unlock(&info_lock);
+
+        return rc;
+}
+
+/* Return configure task for chpid. */
+static enum cfg_task_t cfg_get_task(struct chp_id chpid)
+{
+        return chp_cfg_task[chpid.cssid][chpid.id];
+}
+
+/* Set configure task for chpid. */
+static void cfg_set_task(struct chp_id chpid, enum cfg_task_t cfg)
+{
+        chp_cfg_task[chpid.cssid][chpid.id] = cfg;
+}
+
+/* Perform one configure/deconfigure request. Reschedule work function until
+ * last request. */
+static void cfg_func(struct work_struct *work)
+{
+        struct chp_id chpid;
+        enum cfg_task_t t;
+
+        mutex_lock(&cfg_lock);
+        t = cfg_none;
+        chp_id_for_each(&chpid) {
+                t = cfg_get_task(chpid);
+                if (t != cfg_none) {
+                        cfg_set_task(chpid, cfg_none);
+                        break;
+                }
+        }
+        mutex_unlock(&cfg_lock);
+
+        switch (t) {
+        case cfg_configure:
+                sclp_chp_configure(chpid);
+                info_expire();
+                chsc_chp_online(chpid);
+                break;
+        case cfg_deconfigure:
+                sclp_chp_deconfigure(chpid);
+                info_expire();
+                chsc_chp_offline(chpid);
+                break;
+        case cfg_none:
+                /* Get updated information after last change. */
+                info_update();
+                mutex_lock(&cfg_lock);
+                cfg_busy = 0;
+                mutex_unlock(&cfg_lock);
+                wake_up_interruptible(&cfg_wait_queue);
+                return;
+        }
+        queue_work(chp_wq, &cfg_work);
+}
+
+/**
+ * chp_cfg_schedule - schedule chpid configuration request
+ * @chpid - channel-path ID
+ * @configure - Non-zero for configure, zero for deconfigure
+ *
+ * Schedule a channel-path configuration/deconfiguration request.
+ */
+void chp_cfg_schedule(struct chp_id chpid, int configure)
+{
+        CIO_MSG_EVENT(2, "chp_cfg_sched%x.%02x=%d\n", chpid.cssid, chpid.id,
+                      configure);
+        mutex_lock(&cfg_lock);
+        cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
+        cfg_busy = 1;
+        mutex_unlock(&cfg_lock);
+        queue_work(chp_wq, &cfg_work);
+}
+
+/**
+ * chp_cfg_cancel_deconfigure - cancel chpid deconfiguration request
+ * @chpid - channel-path ID
+ *
+ * Cancel an active channel-path deconfiguration request if it has not yet
+ * been performed.
+ */
+void chp_cfg_cancel_deconfigure(struct chp_id chpid)
+{
+        CIO_MSG_EVENT(2, "chp_cfg_cancel:%x.%02x\n", chpid.cssid, chpid.id);
+        mutex_lock(&cfg_lock);
+        if (cfg_get_task(chpid) == cfg_deconfigure)
+                cfg_set_task(chpid, cfg_none);
+        mutex_unlock(&cfg_lock);
+}
+
+static int cfg_wait_idle(void)
+{
+        if (wait_event_interruptible(cfg_wait_queue, !cfg_busy))
+                return -ERESTARTSYS;
+        return 0;
+}
+
+static int __init chp_init(void)
+{
+        struct chp_id chpid;
+
+        chp_wq = create_singlethread_workqueue("cio_chp");
+        if (!chp_wq)
+                return -ENOMEM;
+        INIT_WORK(&cfg_work, cfg_func);
+        init_waitqueue_head(&cfg_wait_queue);
+        if (info_update())
+                return 0;
+        /* Register available channel-paths. */
+        chp_id_for_each(&chpid) {
+                if (chp_info_get_status(chpid) != CHP_STATUS_NOT_RECOGNIZED)
+                        chp_new(chpid);
+        }
+
+        return 0;
+}
+
+subsys_initcall(chp_init);