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mlxsw: spectrum_buffers: Move here the new headroom code
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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: Petr Machata <petrm@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Petr Machata authored and David S. Miller committed Sep 16, 2020
1 parent 7ace2c3 commit 4c22f29
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201 changes: 0 additions & 201 deletions drivers/net/ethernet/mellanox/mlxsw/spectrum.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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);
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