mlx4_core: Move kernel doorbell management into core

In addition to mlx4_ib, there will be ethernet and FC consumers of
mlx4_core, so move the code for managing kernel doorbells into the
core module to avoid having to duplicate this multiple times.

Signed-off-by: Yevgeny Petrilin <yevgenyp@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

3 files changed, 117 insertions, 0 deletions

diff --git a/drivers/net/mlx4/alloc.c b/drivers/net/mlx4/alloc.c
index 75ef9d0d974d..43c6d04bb880 100644
--- a/drivers/net/mlx4/alloc.c
+++ b/drivers/net/mlx4/alloc.c
@@ -196,3 +196,114 @@ void mlx4_buf_free(struct mlx4_dev *dev, int size, struct mlx4_buf *buf)
         }
 }
 EXPORT_SYMBOL_GPL(mlx4_buf_free);
+
+static struct mlx4_db_pgdir *mlx4_alloc_db_pgdir(struct device *dma_device)
+{
+        struct mlx4_db_pgdir *pgdir;
+
+        pgdir = kzalloc(sizeof *pgdir, GFP_KERNEL);
+        if (!pgdir)
+                return NULL;
+
+        bitmap_fill(pgdir->order1, MLX4_DB_PER_PAGE / 2);
+        pgdir->bits[0] = pgdir->order0;
+        pgdir->bits[1] = pgdir->order1;
+        pgdir->db_page = dma_alloc_coherent(dma_device, PAGE_SIZE,
+                                            &pgdir->db_dma, GFP_KERNEL);
+        if (!pgdir->db_page) {
+                kfree(pgdir);
+                return NULL;
+        }
+
+        return pgdir;
+}
+
+static int mlx4_alloc_db_from_pgdir(struct mlx4_db_pgdir *pgdir,
+                                    struct mlx4_db *db, int order)
+{
+        int o;
+        int i;
+
+        for (o = order; o <= 1; ++o) {
+                i = find_first_bit(pgdir->bits[o], MLX4_DB_PER_PAGE >> o);
+                if (i < MLX4_DB_PER_PAGE >> o)
+                        goto found;
+        }
+
+        return -ENOMEM;
+
+found:
+        clear_bit(i, pgdir->bits[o]);
+
+        i <<= o;
+
+        if (o > order)
+                set_bit(i ^ 1, pgdir->bits[order]);
+
+        db->u.pgdir = pgdir;
+        db->index   = i;
+        db->db      = pgdir->db_page + db->index;
+        db->dma     = pgdir->db_dma  + db->index * 4;
+        db->order   = order;
+
+        return 0;
+}
+
+int mlx4_db_alloc(struct mlx4_dev *dev, struct mlx4_db *db, int order)
+{
+        struct mlx4_priv *priv = mlx4_priv(dev);
+        struct mlx4_db_pgdir *pgdir;
+        int ret = 0;
+
+        mutex_lock(&priv->pgdir_mutex);
+
+        list_for_each_entry(pgdir, &priv->pgdir_list, list)
+                if (!mlx4_alloc_db_from_pgdir(pgdir, db, order))
+                        goto out;
+
+        pgdir = mlx4_alloc_db_pgdir(&(dev->pdev->dev));
+        if (!pgdir) {
+                ret = -ENOMEM;
+                goto out;
+        }
+
+        list_add(&pgdir->list, &priv->pgdir_list);
+
+        /* This should never fail -- we just allocated an empty page: */
+        WARN_ON(mlx4_alloc_db_from_pgdir(pgdir, db, order));
+
+out:
+        mutex_unlock(&priv->pgdir_mutex);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(mlx4_db_alloc);
+
+void mlx4_db_free(struct mlx4_dev *dev, struct mlx4_db *db)
+{
+        struct mlx4_priv *priv = mlx4_priv(dev);
+        int o;
+        int i;
+
+        mutex_lock(&priv->pgdir_mutex);
+
+        o = db->order;
+        i = db->index;
+
+        if (db->order == 0 && test_bit(i ^ 1, db->u.pgdir->order0)) {
+                clear_bit(i ^ 1, db->u.pgdir->order0);
+                ++o;
+        }
+        i >>= o;
+        set_bit(i, db->u.pgdir->bits[o]);
+
+        if (bitmap_full(db->u.pgdir->order1, MLX4_DB_PER_PAGE / 2)) {
+                dma_free_coherent(&(dev->pdev->dev), PAGE_SIZE,
+                                  db->u.pgdir->db_page, db->u.pgdir->db_dma);
+                list_del(&db->u.pgdir->list);
+                kfree(db->u.pgdir);
+        }
+
+        mutex_unlock(&priv->pgdir_mutex);
+}
+EXPORT_SYMBOL_GPL(mlx4_db_free);
diff --git a/drivers/net/mlx4/main.c b/drivers/net/mlx4/main.c
index 49a4acab5e82..a6aa49fc1d68 100644
--- a/drivers/net/mlx4/main.c
+++ b/drivers/net/mlx4/main.c
@@ -798,6 +798,9 @@ static int __mlx4_init_one(struct pci_dev *pdev, const struct pci_device_id *id)
         INIT_LIST_HEAD(&priv->ctx_list);
         spin_lock_init(&priv->ctx_lock);
 
+        INIT_LIST_HEAD(&priv->pgdir_list);
+        mutex_init(&priv->pgdir_mutex);
+
         /*
          * Now reset the HCA before we touch the PCI capabilities or
          * attempt a firmware command, since a boot ROM may have left
diff --git a/drivers/net/mlx4/mlx4.h b/drivers/net/mlx4/mlx4.h
index 73336810e652..a4023c2dd050 100644
--- a/drivers/net/mlx4/mlx4.h
+++ b/drivers/net/mlx4/mlx4.h
@@ -257,6 +257,9 @@ struct mlx4_priv {
         struct list_head        ctx_list;
         spinlock_t              ctx_lock;
 
+        struct list_head        pgdir_list;
+        struct mutex            pgdir_mutex;
+
         struct mlx4_fw          fw;
         struct mlx4_cmd         cmd;