[PATCH net-next v4 3/4] net: dsa: yt921x: Add port police support

David Yang
2026-04-09T17:12:30Z

Enable rate meter ability and support limiting the rate of incoming
traffic.

Signed-off-by: David Yang <mmyangfl@gmail.com>
---
drivers/net/dsa/yt921x.c | 325 ++++++++++++++++++++++++++++++++++++++-
drivers/net/dsa/yt921x.h | 54 +++++++
2 files changed, 378 insertions(+), 1 deletion(-)

diff --git a/drivers/net/dsa/yt921x.c b/drivers/net/dsa/yt921x.c
index 0c07b903fd68..f0ebbcd2151c 100644
--- a/drivers/net/dsa/yt921x.c
+++ b/drivers/net/dsa/yt921x.c
@@ -263,6 +263,14 @@ yt921x_reg_toggle_bits(struct yt921x_priv *priv, u32 reg, u32 mask, bool set)
* eliminate potential issues, although partial reads/writes are also possible.
*/

+static void update_ctrls_unaligned(u32 *lo, u32 *hi, u64 mask, u64 val)
+{
+ *lo &= ~lower_32_bits(mask);
+ *hi &= ~upper_32_bits(mask);
+ *lo |= lower_32_bits(val);
+ *hi |= upper_32_bits(val);
+}
+
static int
yt921x_regs_read(struct yt921x_priv *priv, u32 reg, u32 *vals,
unsigned int num_regs)
@@ -373,6 +381,12 @@ yt921x_reg64_clear_bits(struct yt921x_priv *priv, u32 reg, const u32 *masks)
return yt921x_regs_clear_bits(priv, reg, masks, 2);
}

+static int
+yt921x_reg96_write(struct yt921x_priv *priv, u32 reg, const u32 *vals)
+{
+ return yt921x_regs_write(priv, reg, vals, 3);
+}
+
static int yt921x_reg_mdio_read(void *context, u32 reg, u32 *valp)
{
struct yt921x_reg_mdio *mdio = context;
@@ -1066,6 +1080,13 @@ yt921x_dsa_set_mac_eee(struct dsa_switch *ds, int port, struct ethtool_keee *e)
return res;
}

+static int yt921x_mtu_fetch(struct yt921x_priv *priv, int port)
+{
+ struct dsa_port *dp = dsa_to_port(&priv->ds, port);
+
+ return dp->user ? READ_ONCE(dp->user->mtu) : ETH_DATA_LEN;
+}
+
static int
yt921x_dsa_port_change_mtu(struct dsa_switch *ds, int port, int new_mtu)
{
@@ -1097,6 +1118,268 @@ static int yt921x_dsa_port_max_mtu(struct dsa_switch *ds, int port)
return YT921X_FRAME_SIZE_MAX - ETH_HLEN - ETH_FCS_LEN - YT921X_TAG_LEN;
}

+/* v * 2^e */
+static u64 ldexpu64(u64 v, int e)
+{
+ return e >= 0 ? v << e : v >> -e;
+}
+
+/* slot (ns) * rate (/s) / 10^9 (ns/s) = 2^C * token * 4^unit */
+static u32 rate2token(u64 rate, unsigned int slot_ns, int unit, int C)
+{
+ int e = 2 * unit + C + YT921X_TOKEN_RATE_C;
+
+ return div_u64(ldexpu64(slot_ns * rate, -e), 1000000000);
+}
+
+static u64 token2rate(u32 token, unsigned int slot_ns, int unit, int C)
+{
+ int e = 2 * unit + C + YT921X_TOKEN_RATE_C;
+
+ return div_u64(ldexpu64(mul_u32_u32(1000000000, token), e), slot_ns);
+}
+
+/* burst = 2^C * token * 4^unit */
+static u32 burst2token(u64 burst, int unit, int C)
+{
+ return ldexpu64(burst, -(2 * unit + C));
+}
+
+static u64 token2burst(u32 token, int unit, int C)
+{
+ return ldexpu64(token, 2 * unit + C);
+}
+
+struct yt921x_marker {
+ u32 cir;
+ u32 cbs;
+ u32 ebs;
+ int unit;
+ bool pkt_mode;
+};
+
+#define YT921X_MARKER_PKT_MODE BIT(0)
+#define YT921X_MARKER_SINGLE_BUCKET BIT(1)
+
+static int
+yt921x_marker_tfm(struct yt921x_marker *marker, u64 rate, u64 burst,
+ unsigned int flags, unsigned int slot_ns, u32 cir_max,
+ u32 cbs_max, int unit_max, struct yt921x_priv *priv, int port,
+ struct netlink_ext_ack *extack)
+{
+ const int C = flags & YT921X_MARKER_PKT_MODE ? YT921X_TOKEN_PKT_C :
+ YT921X_TOKEN_BYTE_C;
+ struct device *dev = to_device(priv);
+ struct yt921x_marker m;
+ u64 burst_est;
+ u64 burst_sug;
+ u64 burst_max;
+ u64 rate_max;
+
+ m.unit = unit_max;
+ rate_max = token2rate(cir_max, slot_ns, m.unit, C);
+ burst_max = token2burst(cbs_max, m.unit, C);
+
+ /* Check for unusual values */
+ if (rate > rate_max || burst > burst_max) {
+ NL_SET_ERR_MSG_MOD(extack, "Unexpected tremendous rate");
+ return -ERANGE;
+ }
+
+ /* Check for matching burst */
+ burst_est = div_u64(slot_ns * rate, 1000000000);
+ burst_sug = burst_est;
+ if (flags & YT921X_MARKER_PKT_MODE)
+ burst_sug++;
+ else
+ burst_sug += ETH_HLEN + yt921x_mtu_fetch(priv, port) +
+ ETH_FCS_LEN;
+ if (burst_sug > burst)
+ dev_warn(dev,
+ "Consider burst at least %llu to match rate %llu\n",
+ burst_sug, rate);
+
+ /* Select unit */
+ for (; m.unit > 0; m.unit--) {
+ if (rate > (rate_max >> 2) || burst > (burst_max >> 2))
+ break;
+ rate_max >>= 2;
+ burst_max >>= 2;
+ }
+
+ /* Calculate information rate and bucket size */
+ m.cir = rate2token(rate, slot_ns, m.unit, C);
+ if (!m.cir)
+ m.cir = 1;
+ else if (WARN_ON(m.cir > cir_max))
+ m.cir = cir_max;
+ m.cbs = burst2token(burst, m.unit, C);
+ if (!m.cbs)
+ m.cbs = 1;
+ else if (WARN_ON(m.cbs > cbs_max))
+ m.cbs = cbs_max;
+
+ /* Cut EBS */
+ m.ebs = 0;
+ if (!(flags & YT921X_MARKER_SINGLE_BUCKET)) {
+ /* We don't have a chance to adjust rate when MTU is changed */
+ if (flags & YT921X_MARKER_PKT_MODE)
+ burst_est++;
+ else
+ burst_est += YT921X_FRAME_SIZE_MAX;
+
+ if (burst_est < burst) {
+ u32 pbs = m.cbs;
+
+ m.cbs = burst2token(burst_est, m.unit, C);
+ if (!m.cbs) {
+ m.cbs = 1;
+ } else if (m.cbs > cbs_max) {
+ WARN_ON(1);
+ m.cbs = cbs_max;
+ }
+
+ if (pbs > m.cbs)
+ m.ebs = pbs - m.cbs;
+ }
+ }
+
+ dev_dbg(dev,
+ "slot %u ns, rate %llu, burst %llu -> unit %d, cir %u, cbs %u, ebs %u\n",
+ slot_ns, rate, burst, m.unit, m.cir, m.cbs, m.ebs);
+
+ m.pkt_mode = flags & YT921X_MARKER_PKT_MODE;
+ *marker = m;
+ return 0;
+}
+
+static int
+yt921x_marker_tfm_police(struct yt921x_marker *marker,
+ const struct flow_action_police *police,
+ unsigned int flags, struct yt921x_priv *priv, int port,
+ struct netlink_ext_ack *extack)
+{
+ bool pkt_mode = !!police->rate_pkt_ps;
+ u64 burst;
+ u64 rate;
+
+ rate = pkt_mode ? police->rate_pkt_ps : police->rate_bytes_ps;
+ burst = pkt_mode ? police->burst_pkt : police->burst;
+ if (pkt_mode)
+ flags |= YT921X_MARKER_PKT_MODE;
+
+ return yt921x_marker_tfm(marker, rate, burst, flags,
+ priv->meter_slot_ns, YT921X_METER_CIR_MAX,
+ YT921X_METER_CBS_MAX, YT921X_METER_UNIT_MAX,
+ priv, port, extack);
+}
+
+static int
+yt921x_police_validate(const struct flow_action_police *police,
+ const struct flow_action *action,
+ const struct flow_action_entry *act,
+ struct netlink_ext_ack *extack)
+{
+ if (police->exceed.act_id != FLOW_ACTION_DROP) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "Offload not supported when exceed action is not drop");
+ return -EOPNOTSUPP;
+ }
+
+ if (police->notexceed.act_id != FLOW_ACTION_PIPE &&
+ police->notexceed.act_id != FLOW_ACTION_ACCEPT) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "Offload not supported when conform action is not pipe or ok");
+ return -EOPNOTSUPP;
+ }
+
+ if (police->notexceed.act_id == FLOW_ACTION_ACCEPT && action && act &&
+ !flow_action_is_last_entry(action, act)) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "Offload not supported when conform action is ok, but action is not last");
+ return -EOPNOTSUPP;
+ }
+
+ /* mtu defaults to unlimited but we got 2040 here, don't know why */
+ if (police->peakrate_bytes_ps || police->avrate || police->overhead) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "Offload not supported when peakrate/avrate/overhead is configured");
+ return -EOPNOTSUPP;
+ }
+
+ return 0;
+}
+
+static int
+yt921x_meter_config(struct yt921x_priv *priv, unsigned int id,
+ const struct yt921x_marker *marker)
+{
+ u32 ctrls[3];
+
+ ctrls[0] = 0;
+ ctrls[1] = YT921X_METER_CTRLb_CIR(marker->cir);
+ ctrls[2] = YT921X_METER_CTRLc_UNIT(marker->unit) |
+ YT921X_METER_CTRLc_DROP_R |
+ YT921X_METER_CTRLc_TOKEN_OVERFLOW_EN |
+ YT921X_METER_CTRLc_METER_EN;
+ if (marker->pkt_mode)
+ ctrls[2] |= YT921X_METER_CTRLc_PKT_MODE;
+ update_ctrls_unaligned(&ctrls[0], &ctrls[1],
+ YT921X_METER_CTRLab_EBS_M,
+ YT921X_METER_CTRLab_EBS(marker->ebs));
+ update_ctrls_unaligned(&ctrls[1], &ctrls[2],
+ YT921X_METER_CTRLbc_CBS_M,
+ YT921X_METER_CTRLbc_CBS(marker->cbs));
+
+ return yt921x_reg96_write(priv, YT921X_METERn_CTRL(id), ctrls);
+}
+
+static void yt921x_dsa_port_policer_del(struct dsa_switch *ds, int port)
+{
+ struct yt921x_priv *priv = to_yt921x_priv(ds);
+ struct device *dev = to_device(priv);
+ int res;
+
+ mutex_lock(&priv->reg_lock);
+ res = yt921x_reg_write(priv, YT921X_PORTn_METER(port), 0);
+ mutex_unlock(&priv->reg_lock);
+
+ if (res)
+ dev_err(dev, "Failed to %s port %d: %i\n", "delete policer on",
+ port, res);
+}
+
+static int
+yt921x_dsa_port_policer_add(struct dsa_switch *ds, int port,
+ const struct flow_action_police *police,
+ struct netlink_ext_ack *extack)
+{
+ struct yt921x_priv *priv = to_yt921x_priv(ds);
+ struct yt921x_marker marker;
+ u32 ctrl;
+ int res;
+
+ res = yt921x_police_validate(police, NULL, NULL, extack);
+ if (res)
+ return res;
+
+ res = yt921x_marker_tfm_police(&marker, police, 0, priv, port, extack);
+ if (res)
+ return res;
+
+ mutex_lock(&priv->reg_lock);
+ res = yt921x_meter_config(priv, port + YT921X_METER_NUM, &marker);
+ if (res)
+ goto end;
+
+ ctrl = YT921X_PORT_METER_ID(port) | YT921X_PORT_METER_EN;
+ res = yt921x_reg_write(priv, YT921X_PORTn_METER(port), ctrl);
+end:
+ mutex_unlock(&priv->reg_lock);
+
+ return res;
+}
+
static int
yt921x_mirror_del(struct yt921x_priv *priv, int port, bool ingress)
{
@@ -3052,6 +3335,7 @@ static int yt921x_chip_detect(struct yt921x_priv *priv)
u32 chipid;
u32 major;
u32 mode;
+ u32 val;
int res;

res = yt921x_reg_read(priv, YT921X_CHIP_ID, &chipid);
@@ -3086,12 +3370,27 @@ static int yt921x_chip_detect(struct yt921x_priv *priv)
return -ENODEV;
}

+ res = yt921x_reg_read(priv, YT921X_SYS_CLK, &val);
+ if (res)
+ return res;
+ switch (FIELD_GET(YT921X_SYS_CLK_SEL_M, val)) {
+ case 0:
+ priv->cycle_ns = info->major == YT9215_MAJOR ? 8 : 6;
+ break;
+ case YT921X_SYS_CLK_143M:
+ priv->cycle_ns = 7;
+ break;
+ default:
+ priv->cycle_ns = 8;
+ }
+
/* Print chipid here since we are interested in lower 16 bits */
dev_info(dev,
"Motorcomm %s ethernet switch, chipid: 0x%x, chipmode: 0x%x 0x%x\n",
info->name, chipid, mode, extmode);

priv->info = info;
+
return 0;
}

@@ -3213,6 +3512,23 @@ static int yt921x_chip_setup_dsa(struct yt921x_priv *priv)
return 0;
}

+static int yt921x_chip_setup_tc(struct yt921x_priv *priv)
+{
+ unsigned int op_ns;
+ u32 ctrl;
+ int res;
+
+ op_ns = 8 * priv->cycle_ns;
+
+ ctrl = max(priv->meter_slot_ns / op_ns, YT921X_METER_SLOT_MIN);
+ res = yt921x_reg_write(priv, YT921X_METER_SLOT, ctrl);
+ if (res)
+ return res;
+ priv->meter_slot_ns = ctrl * op_ns;
+
+ return 0;
+}
+
static int __maybe_unused yt921x_chip_setup_qos(struct yt921x_priv *priv)
{
u32 ctrl;
@@ -3259,7 +3575,7 @@ static int yt921x_chip_setup(struct yt921x_priv *priv)
u32 ctrl;
int res;

- ctrl = YT921X_FUNC_MIB;
+ ctrl = YT921X_FUNC_MIB | YT921X_FUNC_METER;
res = yt921x_reg_set_bits(priv, YT921X_FUNC, ctrl);
if (res)
return res;
@@ -3268,6 +3584,10 @@ static int yt921x_chip_setup(struct yt921x_priv *priv)
if (res)
return res;

+ res = yt921x_chip_setup_tc(priv);
+ if (res)
+ return res;
+
#if IS_ENABLED(CONFIG_DCB)
res = yt921x_chip_setup_qos(priv);
if (res)
@@ -3359,6 +3679,9 @@ static const struct dsa_switch_ops yt921x_dsa_switch_ops = {
/* mtu */
.port_change_mtu = yt921x_dsa_port_change_mtu,
.port_max_mtu = yt921x_dsa_port_max_mtu,
+ /* rate */
+ .port_policer_del = yt921x_dsa_port_policer_del,
+ .port_policer_add = yt921x_dsa_port_policer_add,
/* hsr */
.port_hsr_leave = dsa_port_simple_hsr_leave,
.port_hsr_join = dsa_port_simple_hsr_join,
diff --git a/drivers/net/dsa/yt921x.h b/drivers/net/dsa/yt921x.h
index 4989d87c2492..01cc2298be94 100644
--- a/drivers/net/dsa/yt921x.h
+++ b/drivers/net/dsa/yt921x.h
@@ -23,6 +23,7 @@
#define YT921X_RST_HW BIT(31)
#define YT921X_RST_SW BIT(1)
#define YT921X_FUNC 0x80004
+#define YT921X_FUNC_METER BIT(4)
#define YT921X_FUNC_MIB BIT(1)
#define YT921X_CHIP_ID 0x80008
#define YT921X_CHIP_ID_MAJOR GENMASK(31, 16)
@@ -239,6 +240,11 @@
#define YT921X_EDATA_DATA_STATUS_M GENMASK(3, 0)
#define YT921X_EDATA_DATA_STATUS(x) FIELD_PREP(YT921X_EDATA_DATA_STATUS_M, (x))
#define YT921X_EDATA_DATA_IDLE YT921X_EDATA_DATA_STATUS(3)
+#define YT921X_SYS_CLK 0xe0040
+#define YT921X_SYS_CLK_SEL_M GENMASK(1, 0) /* unknown: 167M */
+#define YT9215_SYS_CLK_125M 0
+#define YT9218_SYS_CLK_167M 0
+#define YT921X_SYS_CLK_143M 1

#define YT921X_EXT_MBUS_OP 0x6a000
#define YT921X_INT_MBUS_OP 0xf0000
@@ -465,6 +471,42 @@ enum yt921x_app_selector {
#define YT921X_LAG_HASH_MAC_DA BIT(1)
#define YT921X_LAG_HASH_SRC_PORT BIT(0)

+#define YT921X_PORTn_RATE(port) (0x220000 + 4 * (port))
+#define YT921X_PORT_RATE_GAP_VALUE GENMASK(4, 0) /* default 20 */
+#define YT921X_METER_SLOT 0x220104
+#define YT921X_METER_SLOT_SLOT_M GENMASK(11, 0)
+#define YT921X_PORTn_METER(port) (0x220108 + 4 * (port))
+#define YT921X_PORT_METER_EN BIT(4)
+#define YT921X_PORT_METER_ID_M GENMASK(3, 0)
+#define YT921X_PORT_METER_ID(x) FIELD_PREP(YT921X_PORT_METER_ID_M, (x))
+#define YT921X_METERn_CTRL(x) (0x220800 + 0x10 * (x))
+#define YT921X_METER_CTRLc_METER_EN BIT(14)
+#define YT921X_METER_CTRLc_TOKEN_OVERFLOW_EN BIT(13) /* RFC4115: yellow use unused green bw */
+#define YT921X_METER_CTRLc_DROP_M GENMASK(12, 11)
+#define YT921X_METER_CTRLc_DROP(x) FIELD_PREP(YT921X_METER_CTRLc_DROP_M, (x))
+#define YT921X_METER_CTRLc_DROP_GYR YT921X_METER_CTRLc_DROP(0)
+#define YT921X_METER_CTRLc_DROP_YR YT921X_METER_CTRLc_DROP(1)
+#define YT921X_METER_CTRLc_DROP_R YT921X_METER_CTRLc_DROP(2)
+#define YT921X_METER_CTRLc_DROP_NONE YT921X_METER_CTRLc_DROP(3)
+#define YT921X_METER_CTRLc_COLOR_BLIND BIT(10)
+#define YT921X_METER_CTRLc_UNIT_M GENMASK(9, 7)
+#define YT921X_METER_CTRLc_UNIT(x) FIELD_PREP(YT921X_METER_CTRLc_UNIT_M, (x))
+#define YT921X_METER_CTRLc_BYTE_MODE_INCLUDE_GAP BIT(6) /* +GAP_VALUE bytes each packet */
+#define YT921X_METER_CTRLc_PKT_MODE BIT(5) /* 0: byte rate mode */
+#define YT921X_METER_CTRLc_RFC2698 BIT(4) /* 0: RFC4115 */
+#define YT921X_METER_CTRLbc_CBS_M GENMASK_ULL(35, 20)
+#define YT921X_METER_CTRLbc_CBS(x) FIELD_PREP(YT921X_METER_CTRLbc_CBS_M, (x))
+#define YT921X_METER_CTRLb_CIR_M GENMASK(19, 2)
+#define YT921X_METER_CTRLb_CIR(x) FIELD_PREP(YT921X_METER_CTRLb_CIR_M, (x))
+#define YT921X_METER_CTRLab_EBS_M GENMASK_ULL(33, 18)
+#define YT921X_METER_CTRLab_EBS(x) FIELD_PREP(YT921X_METER_CTRLab_EBS_M, (x))
+#define YT921X_METER_CTRLa_EIR_M GENMASK(17, 0)
+#define YT921X_METER_CTRLa_EIR(x) FIELD_PREP(YT921X_METER_CTRLa_EIR_M, (x))
+#define YT921X_METERn_STAT_EXCESS(x) (0x221000 + 8 * (x))
+#define YT921X_METERn_STAT_COMMITTED(x) (0x221004 + 8 * (x))
+#define YT921X_METER_STAT_TOKEN_M GENMASK(30, 15)
+#define YT921X_METER_STAT_QUEUE_M GENMASK(14, 0)
+
#define YT921X_PORTn_VLAN_CTRL(port) (0x230010 + 4 * (port))
#define YT921X_PORT_VLAN_CTRL_SVLAN_PRIO_EN BIT(31)
#define YT921X_PORT_VLAN_CTRL_CVLAN_PRIO_EN BIT(30)
@@ -508,6 +550,16 @@ enum yt921x_fdb_entry_status {

#define YT921X_MSTI_NUM 16

+#define YT921X_TOKEN_BYTE_C 1 /* 1 token = 2^1 byte */
+#define YT921X_TOKEN_PKT_C -6 /* 1 token = 2^-6 packets */
+#define YT921X_TOKEN_RATE_C -15
+/* Custom meters only, not including dedicated port meters (11) */
+#define YT921X_METER_NUM 64
+#define YT921X_METER_SLOT_MIN 80
+#define YT921X_METER_UNIT_MAX ((1 << 3) - 1)
+#define YT921X_METER_CIR_MAX ((1 << 18) - 1)
+#define YT921X_METER_CBS_MAX ((1 << 16) - 1)
+
#define YT921X_LAG_NUM 2
#define YT921X_LAG_PORT_NUM 4

@@ -602,8 +654,10 @@ struct yt921x_priv {
struct dsa_switch ds;

const struct yt921x_info *info;
+ unsigned int meter_slot_ns;
/* cache of dsa_cpu_ports(ds) */
u16 cpu_ports_mask;
+ unsigned char cycle_ns;

/* protect the access to the switch registers */
struct mutex reg_lock;
--
2.53.0