[SPARC64]: Abstract out mdesc accesses for better MD update handling.

Since we have to be able to handle MD updates, having an in-tree
set of data structures representing the MD objects actually makes
things more painful.

The MD itself is easy to parse, and we can implement the existing
interfaces using direct parsing of the MD binary image.

The MD is now reference counted, so accesses have to now take the
form:

	handle = mdesc_grab();

	... operations on MD ...

	mdesc_release(handle);

The only remaining issue are cases where code holds on to references
to MD property values.  mdesc_get_property() returns a direct pointer
to the property value, most cases just pull in the information they
need and discard the pointer, but there are few that use the pointer
directly over a long lifetime.  Those will be fixed up in a subsequent
changeset.

A preliminary handler for MD update events from domain services is
there, it is rudimentry but it works and handles all of the reference
counting.  It does not check the generation number of the MDs,
and it does not generate a "add/delete" list for notification to
interesting parties about MD changes but that will be forthcoming.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 76 insertions, 67 deletions

diff --git a/arch/sparc64/kernel/vio.c b/arch/sparc64/kernel/vio.c
index 7eccc91cd59d..64f082555bcd 100644
--- a/arch/sparc64/kernel/vio.c
+++ b/arch/sparc64/kernel/vio.c
@@ -147,30 +147,6 @@ void vio_unregister_driver(struct vio_driver *viodrv)
 }
 EXPORT_SYMBOL(vio_unregister_driver);
 
-struct mdesc_node *vio_find_endpoint(struct vio_dev *vdev)
-{
-        struct mdesc_node *endp, *mp = vdev->mp;
-        int i;
-
-        endp = NULL;
-        for (i = 0; i < mp->num_arcs; i++) {
-                struct mdesc_node *t;
-
-                if (strcmp(mp->arcs[i].name, "fwd"))
-                        continue;
-
-                t = mp->arcs[i].arc;
-                if (strcmp(t->name, "channel-endpoint"))
-                        continue;
-
-                endp = t;
-                break;
-        }
-
-        return endp;
-}
-EXPORT_SYMBOL(vio_find_endpoint);
-
 static void __devinit vio_dev_release(struct device *dev)
 {
         kfree(to_vio_dev(dev));
@@ -197,22 +173,47 @@ struct device_node *cdev_node;
 static struct vio_dev *root_vdev;
 static u64 cdev_cfg_handle;
 
-static struct vio_dev *vio_create_one(struct mdesc_node *mp,
+static void vio_fill_channel_info(struct mdesc_handle *hp, u64 mp,
+                                  struct vio_dev *vdev)
+{
+        u64 a;
+
+        mdesc_for_each_arc(a, hp, mp, MDESC_ARC_TYPE_FWD) {
+                const u64 *chan_id;
+                const u64 *irq;
+                u64 target;
+
+                target = mdesc_arc_target(hp, a);
+
+                irq = mdesc_get_property(hp, target, "tx-ino", NULL);
+                if (irq)
+                        vdev->tx_irq = sun4v_build_virq(cdev_cfg_handle, *irq);
+
+                irq = mdesc_get_property(hp, target, "rx-ino", NULL);
+                if (irq)
+                        vdev->rx_irq = sun4v_build_virq(cdev_cfg_handle, *irq);
+
+                chan_id = mdesc_get_property(hp, target, "id", NULL);
+                if (chan_id)
+                        vdev->channel_id = *chan_id;
+        }
+}
+
+static struct vio_dev *vio_create_one(struct mdesc_handle *hp, u64 mp,
                                       struct device *parent)
 {
         const char *type, *compat;
         struct device_node *dp;
         struct vio_dev *vdev;
-        const u64 *irq;
         int err, clen;
 
-        type = md_get_property(mp, "device-type", NULL);
+        type = mdesc_get_property(hp, mp, "device-type", NULL);
         if (!type) {
-                type = md_get_property(mp, "name", NULL);
+                type = mdesc_get_property(hp, mp, "name", NULL);
                 if (!type)
-                        type = mp->name;
+                        type = mdesc_node_name(hp, mp);
         }
-        compat = md_get_property(mp, "device-type", &clen);
+        compat = mdesc_get_property(hp, mp, "device-type", &clen);
 
         vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
         if (!vdev) {
@@ -225,15 +226,13 @@ static struct vio_dev *vio_create_one(struct mdesc_node *mp,
         vdev->compat = compat;
         vdev->compat_len = clen;
 
-        irq = md_get_property(mp, "tx-ino", NULL);
-        if (irq)
-                mp->irqs[0] = sun4v_build_virq(cdev_cfg_handle, *irq);
+        vdev->channel_id = ~0UL;
+        vdev->tx_irq = ~0;
+        vdev->rx_irq = ~0;
 
-        irq = md_get_property(mp, "rx-ino", NULL);
-        if (irq)
-                mp->irqs[1] = sun4v_build_virq(cdev_cfg_handle, *irq);
+        vio_fill_channel_info(hp, mp, vdev);
 
-        snprintf(vdev->dev.bus_id, BUS_ID_SIZE, "%lx", mp->node);
+        snprintf(vdev->dev.bus_id, BUS_ID_SIZE, "%lx", mp);
         vdev->dev.parent = parent;
         vdev->dev.bus = &vio_bus_type;
         vdev->dev.release = vio_dev_release;
@@ -267,46 +266,43 @@ static struct vio_dev *vio_create_one(struct mdesc_node *mp,
         return vdev;
 }
 
-static void walk_tree(struct mdesc_node *n, struct vio_dev *parent)
+static void walk_tree(struct mdesc_handle *hp, u64 n, struct vio_dev *parent)
 {
-        int i;
+        u64 a;
 
-        for (i = 0; i < n->num_arcs; i++) {
-                struct mdesc_node *mp;
+        mdesc_for_each_arc(a, hp, n, MDESC_ARC_TYPE_FWD) {
                 struct vio_dev *vdev;
+                u64 target;
 
-                if (strcmp(n->arcs[i].name, "fwd"))
-                        continue;
-
-                mp = n->arcs[i].arc;
-
-                vdev = vio_create_one(mp, &parent->dev);
-                if (vdev && mp->num_arcs)
-                        walk_tree(mp, vdev);
+                target = mdesc_arc_target(hp, a);
+                vdev = vio_create_one(hp, target, &parent->dev);
+                if (vdev)
+                        walk_tree(hp, target, vdev);
         }
 }
 
-static void create_devices(struct mdesc_node *root)
+static void create_devices(struct mdesc_handle *hp, u64 root)
 {
-        struct mdesc_node *mp;
+        u64 mp;
 
-        root_vdev = vio_create_one(root, NULL);
+        root_vdev = vio_create_one(hp, root, NULL);
         if (!root_vdev) {
                 printk(KERN_ERR "VIO: Coult not create root device.\n");
                 return;
         }
 
-        walk_tree(root, root_vdev);
+        walk_tree(hp, root, root_vdev);
 
         /* Domain services is odd as it doesn't sit underneath the
          * channel-devices node, so we plug it in manually.
          */
-        mp = md_find_node_by_name(NULL, "domain-services");
-        if (mp) {
-                struct vio_dev *parent = vio_create_one(mp, &root_vdev->dev);
+        mp = mdesc_node_by_name(hp, MDESC_NODE_NULL, "domain-services");
+        if (mp != MDESC_NODE_NULL) {
+                struct vio_dev *parent = vio_create_one(hp, mp,
+                                                        &root_vdev->dev);
 
                 if (parent)
-                        walk_tree(mp, parent);
+                        walk_tree(hp, mp, parent);
         }
 }
 
@@ -316,40 +312,47 @@ const char *cfg_handle_prop = "cfg-handle";
 
 static int __init vio_init(void)
 {
-        struct mdesc_node *root;
+        struct mdesc_handle *hp;
         const char *compat;
         const u64 *cfg_handle;
         int err, len;
+        u64 root;
+
+        hp = mdesc_grab();
+        if (!hp)
+                return 0;
 
-        root = md_find_node_by_name(NULL, channel_devices_node);
-        if (!root) {
+        root = mdesc_node_by_name(hp, MDESC_NODE_NULL, channel_devices_node);
+        if (root == MDESC_NODE_NULL) {
                 printk(KERN_INFO "VIO: No channel-devices MDESC node.\n");
+                mdesc_release(hp);
                 return 0;
         }
 
         cdev_node = of_find_node_by_name(NULL, "channel-devices");
+        err = -ENODEV;
         if (!cdev_node) {
                 printk(KERN_INFO "VIO: No channel-devices OBP node.\n");
-                return -ENODEV;
+                goto out_release;
         }
 
-        compat = md_get_property(root, "compatible", &len);
+        compat = mdesc_get_property(hp, root, "compatible", &len);
         if (!compat) {
                 printk(KERN_ERR "VIO: Channel devices lacks compatible "
                        "property\n");
-                return -ENODEV;
+                goto out_release;
         }
         if (!find_in_proplist(compat, channel_devices_compat, len)) {
                 printk(KERN_ERR "VIO: Channel devices node lacks (%s) "
                        "compat entry.\n", channel_devices_compat);
-                return -ENODEV;
+                goto out_release;
         }
 
-        cfg_handle = md_get_property(root, cfg_handle_prop, NULL);
+        cfg_handle = mdesc_get_property(hp, root, cfg_handle_prop, NULL);
         if (!cfg_handle) {
                 printk(KERN_ERR "VIO: Channel devices lacks %s property\n",
                        cfg_handle_prop);
-                return -ENODEV;
+                goto out_release;
         }
 
         cdev_cfg_handle = *cfg_handle;
@@ -361,9 +364,15 @@ static int __init vio_init(void)
                 return err;
         }
 
-        create_devices(root);
+        create_devices(hp, root);
+
+        mdesc_release(hp);
 
         return 0;
+
+out_release:
+        mdesc_release(hp);
+        return err;
 }
 
 postcore_initcall(vio_init);