From: Petr Machata <pe...@mellanox.com>
The recommendation for headroom size for 100Gbps port and 100m cable is
101.6KB, reduced accordingly for split ports. The closest higher number
evenly divisible by cell size for both Spectrum-1 and Spectrum-2, and
such that the number of cells can be further divided by maximum split
factor of 4, is 102528 bytes, or 25632 bytes per lane.
Update mlxsw_sp_port_pb_init() to compute the headroom taking into
account this recommended per-lane value and number of lanes actually
dedicated to a given port.
Signed-off-by: Petr Machata <pe...@mellanox.com>
Signed-off-by: Ido Schimmel <ido...@mellanox.com>
---
.../ethernet/mellanox/mlxsw/spectrum_buffers.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c
b/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c
index bb327dfe1336..65ef4a9f6afb 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c
@@ -260,24 +260,24 @@ static int mlxsw_sp_sb_pm_occ_query(struct mlxsw_sp
*mlxsw_sp, u8 local_port,
(unsigned long) pm);
}
-static const u16 mlxsw_sp_pbs[] = {
- [0] = 2 * ETH_FRAME_LEN,
- [9] = 2 * MLXSW_PORT_MAX_MTU,
-};
-
-#define MLXSW_SP_PBS_LEN ARRAY_SIZE(mlxsw_sp_pbs)
+/* 1/4 of a headroom necessary for 100Gbps port and 100m cable. */
+#define MLXSW_SP_PB_HEADROOM 25632
#define MLXSW_SP_PB_UNUSED 8
static int mlxsw_sp_port_pb_init(struct mlxsw_sp_port *mlxsw_sp_port)
{
+ const u32 pbs[] = {
+ [0] = MLXSW_SP_PB_HEADROOM * mlxsw_sp_port->mapping.width,
+ [9] = 2 * MLXSW_PORT_MAX_MTU,
+ };
struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
char pbmc_pl[MLXSW_REG_PBMC_LEN];
int i;
mlxsw_reg_pbmc_pack(pbmc_pl, mlxsw_sp_port->local_port,
0xffff, 0xffff / 2);
- for (i = 0; i < MLXSW_SP_PBS_LEN; i++) {
- u16 size = mlxsw_sp_bytes_cells(mlxsw_sp, mlxsw_sp_pbs[i]);
+ for (i = 0; i < ARRAY_SIZE(pbs); i++) {
+ u16 size = mlxsw_sp_bytes_cells(mlxsw_sp, pbs[i]);
if (i == MLXSW_SP_PB_UNUSED)
continue;
--
2.20.1
