net/mlx5: Fix global UAR mapping

Avoid double mapping of io mapped memory, Device page may be
mapped to non-cached(NC) or to write-combining(WC).
The code before this fix tries to map it both to WC and NC
contrary to what stated in Intel's software developer manual.

Here we remove the global WC mapping of all UARS
"dev->priv.bf_mapping", since UAR mapping should be decided
per UAR (e.g we want different mappings for EQs, CQs vs QPs).

Caller will now have to choose whether to map via
write-combining API or not.

mlx5e SQs will choose write-combining in order to perform
BlueFlame writes.

Fixes: 88a85f99e51f ('TX latency optimization to save DMA reads')
Signed-off-by: Moshe Lazer <moshel@mellanox.com>
Reviewed-by: Achiad Shochat <achiad@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 18 insertions, 11 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/uar.c b/drivers/net/ethernet/mellanox/mlx5/core/uar.c
index eb05c845ece9..8ba080e441a1 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/uar.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/uar.c
@@ -226,7 +226,8 @@ int mlx5_free_uuars(struct mlx5_core_dev *dev, struct mlx5_uuar_info *uuari)
 	return 0;
 }
 
-int mlx5_alloc_map_uar(struct mlx5_core_dev *mdev, struct mlx5_uar *uar)
+int mlx5_alloc_map_uar(struct mlx5_core_dev *mdev, struct mlx5_uar *uar,
+		       bool map_wc)
 {
 	phys_addr_t pfn;
 	phys_addr_t uar_bar_start;
@@ -240,20 +241,26 @@ int mlx5_alloc_map_uar(struct mlx5_core_dev *mdev, struct mlx5_uar *uar)
 
 	uar_bar_start = pci_resource_start(mdev->pdev, 0);
 	pfn           = (uar_bar_start >> PAGE_SHIFT) + uar->index;
-	uar->map      = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
-	if (!uar->map) {
-		mlx5_core_warn(mdev, "ioremap() failed, %d\n", err);
-		err = -ENOMEM;
-		goto err_free_uar;
-	}
 
-	if (mdev->priv.bf_mapping)
-		uar->bf_map = io_mapping_map_wc(mdev->priv.bf_mapping,
-						uar->index << PAGE_SHIFT);
+	if (map_wc) {
+		uar->bf_map = ioremap_wc(pfn << PAGE_SHIFT, PAGE_SIZE);
+		if (!uar->bf_map) {
+			mlx5_core_warn(mdev, "ioremap_wc() failed\n");
+			uar->map = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
+			if (!uar->map)
+				goto err_free_uar;
+		}
+	} else {
+		uar->map = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
+		if (!uar->map)
+			goto err_free_uar;
+	}
 
 	return 0;
 
 err_free_uar:
+	mlx5_core_warn(mdev, "ioremap() failed\n");
+	err = -ENOMEM;
 	mlx5_cmd_free_uar(mdev, uar->index);
 
 	return err;
@@ -262,8 +269,8 @@ EXPORT_SYMBOL(mlx5_alloc_map_uar);
 
 void mlx5_unmap_free_uar(struct mlx5_core_dev *mdev, struct mlx5_uar *uar)
 {
-	io_mapping_unmap(uar->bf_map);
 	iounmap(uar->map);
+	iounmap(uar->bf_map);
 	mlx5_cmd_free_uar(mdev, uar->index);
 }
 EXPORT_SYMBOL(mlx5_unmap_free_uar);