Commit 4c22f29f authored by Petr Machata's avatar Petr Machata Committed by David S. Miller
Browse files

mlxsw: spectrum_buffers: Move here the new headroom code 



Move all the headroom code to the spectrum_buffers module, where it
belongs.

Rename mlxsw_sp_pg_buf_threshold_get() and mlxsw_sp_pg_buf_pack() to
..._hdroom_... to match the naming convention of the new headroom code.

Signed-off-by: default avatarPetr Machata <petrm@nvidia.com>
Reviewed-by: default avatarJiri Pirko <jiri@nvidia.com>
Signed-off-by: default avatarIdo Schimmel <idosch@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7ace2c36

drivers/net/ethernet/mellanox/mlxsw/spectrum.c

+0 −201
Original line number Diff line number Diff line
@@ -610,207 +610,6 @@ static int mlxsw_sp_port_set_mac_address(struct net_device *dev, void *p) 
	return 0;

}



static u16 mlxsw_sp_pg_buf_threshold_get(const struct mlxsw_sp *mlxsw_sp,

					 int mtu)

{

	return 2 * mlxsw_sp_bytes_cells(mlxsw_sp, mtu);

}



static void mlxsw_sp_pg_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_pg_buf_threshold_get(mlxsw_sp, hdroom->mtu);

			delay_cells = 0;

		} else {

			thres_cells = mlxsw_sp_pg_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_pg_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_change_mtu(struct net_device *dev, int mtu)

{

	struct mlxsw_sp_port *mlxsw_sp_port = netdev_priv(dev);

drivers/net/ethernet/mellanox/mlxsw/spectrum_buffers.c

+199 −0
Original line number Diff line number Diff line
@@ -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;

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