mlx4_core: Use MOD_STAT_CFG command to get minimal page size

There was a bug in some versions of the mlx4 driver in
mlx4_alloc_fmr(), which hardcoded the minimum acceptable page_shift to
be 12.  However, new ConnectX firmware can support a minimum
page_shift of 9 (log_pg_sz of 9 returned by QUERY_DEV_LIM) -- so with
old drivers, ib_fmr_alloc() would fail for ULPs using the device
minimum when creating FMRs.

To preserve firmware compatibility with released mlx4 drivers, the
firmware will continue to return 12 as before for log_page_sz in
QUERY_DEV_CAP for these drivers.  However, to enable new drivers to
take advantage of the available smaller page size, the mlx4 driver now
first sets the log_pg_sz to the device minimum by setting a
log_page_sz value to 0 via the MOD_STAT_CFG command and then reading
the real minimum via QUERY_DEV_CAP.

Signed-off-by: Jack Morgenstein <jackm@mellanox.co.il>
Signed-off-by: Vladimir Sokolovsky <vlad@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/drivers/net/mlx4/fw.h b/drivers/net/mlx4/fw.h
index 306cb9b0242d..a0e046c149b7 100644
--- a/drivers/net/mlx4/fw.h
+++ b/drivers/net/mlx4/fw.h
@@ -38,6 +38,11 @@
 #include "mlx4.h"
 #include "icm.h"
 
+struct mlx4_mod_stat_cfg {
+        u8 log_pg_sz;
+        u8 log_pg_sz_m;
+};
+
 struct mlx4_dev_cap {
         int max_srq_sz;
         int max_qp_sz;
@@ -162,5 +167,6 @@ int mlx4_SET_ICM_SIZE(struct mlx4_dev *dev, u64 icm_size, u64 *aux_pages);
 int mlx4_MAP_ICM_AUX(struct mlx4_dev *dev, struct mlx4_icm *icm);
 int mlx4_UNMAP_ICM_AUX(struct mlx4_dev *dev);
 int mlx4_NOP(struct mlx4_dev *dev);
+int mlx4_MOD_STAT_CFG(struct mlx4_dev *dev, struct mlx4_mod_stat_cfg *cfg);
 
 #endif /* MLX4_FW_H */