diff options
Diffstat (limited to 'drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c')
-rw-r--r-- | drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c index c30bbc62e7b0..1f44add89a6c 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c @@ -354,6 +354,205 @@ void mlxsw_sp_hdroom_bufs_reset_lossiness(struct mlxsw_sp_hdroom *hdroom) } } +static u16 mlxsw_sp_hdroom_buf_threshold_get(const struct mlxsw_sp *mlxsw_sp, int mtu) +{ + return 2 * mlxsw_sp_bytes_cells(mlxsw_sp, mtu); +} + +static void mlxsw_sp_hdroom_buf_pack(char *pbmc_pl, int index, u16 size, u16 thres, bool lossy) +{ + if (lossy) + mlxsw_reg_pbmc_lossy_buffer_pack(pbmc_pl, index, size); + else + mlxsw_reg_pbmc_lossless_buffer_pack(pbmc_pl, index, size, + thres); +} + +static u16 mlxsw_sp_hdroom_buf_delay_get(const struct mlxsw_sp *mlxsw_sp, + const struct mlxsw_sp_hdroom *hdroom) +{ + u16 delay_cells; + + delay_cells = mlxsw_sp_bytes_cells(mlxsw_sp, hdroom->delay_bytes); + + /* In the worst case scenario the delay will be made up of packets that + * are all of size CELL_SIZE + 1, which means each packet will require + * almost twice its true size when buffered in the switch. We therefore + * multiply this value by the "cell factor", which is close to 2. + * + * Another MTU is added in case the transmitting host already started + * transmitting a maximum length frame when the PFC packet was received. + */ + return 2 * delay_cells + mlxsw_sp_bytes_cells(mlxsw_sp, hdroom->mtu); +} + +static bool mlxsw_sp_hdroom_buf_is_used(const struct mlxsw_sp_hdroom *hdroom, int buf) +{ + int prio; + + for (prio = 0; prio < IEEE_8021QAZ_MAX_TCS; prio++) { + if (hdroom->prios.prio[prio].buf_idx == buf) + return true; + } + return false; +} + +void mlxsw_sp_hdroom_bufs_reset_sizes(struct mlxsw_sp_port *mlxsw_sp_port, + struct mlxsw_sp_hdroom *hdroom) +{ + struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp; + int i; + + for (i = 0; i < DCBX_MAX_BUFFERS; i++) { + struct mlxsw_sp_hdroom_buf *buf = &hdroom->bufs.buf[i]; + u16 thres_cells; + u16 delay_cells; + + if (!mlxsw_sp_hdroom_buf_is_used(hdroom, i)) { + thres_cells = 0; + delay_cells = 0; + } else if (buf->lossy) { + thres_cells = mlxsw_sp_hdroom_buf_threshold_get(mlxsw_sp, hdroom->mtu); + delay_cells = 0; + } else { + thres_cells = mlxsw_sp_hdroom_buf_threshold_get(mlxsw_sp, hdroom->mtu); + delay_cells = mlxsw_sp_hdroom_buf_delay_get(mlxsw_sp, hdroom); + } + + thres_cells = mlxsw_sp_port_headroom_8x_adjust(mlxsw_sp_port, thres_cells); + delay_cells = mlxsw_sp_port_headroom_8x_adjust(mlxsw_sp_port, delay_cells); + + buf->thres_cells = thres_cells; + buf->size_cells = thres_cells + delay_cells; + } +} + +static int mlxsw_sp_hdroom_configure_buffers(struct mlxsw_sp_port *mlxsw_sp_port, + const struct mlxsw_sp_hdroom *hdroom, bool force) +{ + struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp; + char pbmc_pl[MLXSW_REG_PBMC_LEN]; + bool dirty; + int err; + int i; + + dirty = memcmp(&mlxsw_sp_port->hdroom->bufs, &hdroom->bufs, sizeof(hdroom->bufs)); + if (!dirty && !force) + return 0; + + mlxsw_reg_pbmc_pack(pbmc_pl, mlxsw_sp_port->local_port, 0, 0); + err = mlxsw_reg_query(mlxsw_sp->core, MLXSW_REG(pbmc), pbmc_pl); + if (err) + return err; + + for (i = 0; i < DCBX_MAX_BUFFERS; i++) { + const struct mlxsw_sp_hdroom_buf *buf = &hdroom->bufs.buf[i]; + + mlxsw_sp_hdroom_buf_pack(pbmc_pl, i, buf->size_cells, buf->thres_cells, buf->lossy); + } + + mlxsw_reg_pbmc_lossy_buffer_pack(pbmc_pl, MLXSW_REG_PBMC_PORT_SHARED_BUF_IDX, 0); + err = mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(pbmc), pbmc_pl); + if (err) + return err; + + mlxsw_sp_port->hdroom->bufs = hdroom->bufs; + return 0; +} + +static int mlxsw_sp_hdroom_configure_priomap(struct mlxsw_sp_port *mlxsw_sp_port, + const struct mlxsw_sp_hdroom *hdroom, bool force) +{ + char pptb_pl[MLXSW_REG_PPTB_LEN]; + bool dirty; + int prio; + int err; + + dirty = memcmp(&mlxsw_sp_port->hdroom->prios, &hdroom->prios, sizeof(hdroom->prios)); + if (!dirty && !force) + return 0; + + mlxsw_reg_pptb_pack(pptb_pl, mlxsw_sp_port->local_port); + for (prio = 0; prio < IEEE_8021QAZ_MAX_TCS; prio++) + mlxsw_reg_pptb_prio_to_buff_pack(pptb_pl, prio, hdroom->prios.prio[prio].buf_idx); + + err = mlxsw_reg_write(mlxsw_sp_port->mlxsw_sp->core, MLXSW_REG(pptb), pptb_pl); + if (err) + return err; + + mlxsw_sp_port->hdroom->prios = hdroom->prios; + return 0; +} + +static bool mlxsw_sp_hdroom_bufs_fit(struct mlxsw_sp *mlxsw_sp, + const struct mlxsw_sp_hdroom *hdroom) +{ + u32 taken_headroom_cells = 0; + u32 max_headroom_cells; + int i; + + for (i = 0; i < MLXSW_SP_PB_COUNT; i++) + taken_headroom_cells += hdroom->bufs.buf[i].size_cells; + + max_headroom_cells = mlxsw_sp_sb_max_headroom_cells(mlxsw_sp); + return taken_headroom_cells <= max_headroom_cells; +} + +static int __mlxsw_sp_hdroom_configure(struct mlxsw_sp_port *mlxsw_sp_port, + const struct mlxsw_sp_hdroom *hdroom, bool force) +{ + struct mlxsw_sp_hdroom orig_hdroom; + struct mlxsw_sp_hdroom tmp_hdroom; + int err; + int i; + + /* Port buffers need to be configured in three steps. First, all buffers + * with non-zero size are configured. Then, prio-to-buffer map is + * updated, allowing traffic to flow to the now non-zero buffers. + * Finally, zero-sized buffers are configured, because now no traffic + * should be directed to them anymore. This way, in a non-congested + * system, no packet drops are introduced by the reconfiguration. + */ + + orig_hdroom = *mlxsw_sp_port->hdroom; + tmp_hdroom = orig_hdroom; + for (i = 0; i < MLXSW_SP_PB_COUNT; i++) { + if (hdroom->bufs.buf[i].size_cells) + tmp_hdroom.bufs.buf[i] = hdroom->bufs.buf[i]; + } + + if (!mlxsw_sp_hdroom_bufs_fit(mlxsw_sp_port->mlxsw_sp, &tmp_hdroom) || + !mlxsw_sp_hdroom_bufs_fit(mlxsw_sp_port->mlxsw_sp, hdroom)) + return -ENOBUFS; + + err = mlxsw_sp_hdroom_configure_buffers(mlxsw_sp_port, &tmp_hdroom, force); + if (err) + return err; + + err = mlxsw_sp_hdroom_configure_priomap(mlxsw_sp_port, hdroom, force); + if (err) + goto err_configure_priomap; + + err = mlxsw_sp_hdroom_configure_buffers(mlxsw_sp_port, hdroom, false); + if (err) + goto err_configure_buffers; + + *mlxsw_sp_port->hdroom = *hdroom; + return 0; + +err_configure_buffers: + mlxsw_sp_hdroom_configure_priomap(mlxsw_sp_port, &tmp_hdroom, false); +err_configure_priomap: + mlxsw_sp_hdroom_configure_buffers(mlxsw_sp_port, &orig_hdroom, false); + return err; +} + +int mlxsw_sp_hdroom_configure(struct mlxsw_sp_port *mlxsw_sp_port, + const struct mlxsw_sp_hdroom *hdroom) +{ + return __mlxsw_sp_hdroom_configure(mlxsw_sp_port, hdroom, false); +} + static int mlxsw_sp_port_headroom_init(struct mlxsw_sp_port *mlxsw_sp_port) { int err; |