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Message-ID: <20260129085139.2767649-4-mmyangfl@gmail.com>
Date: Thu, 29 Jan 2026 16:51:35 +0800
From: David Yang <mmyangfl@...il.com>
To: netdev@...r.kernel.org
Cc: David Yang <mmyangfl@...il.com>,
Andrew Lunn <andrew@...n.ch>,
Vladimir Oltean <olteanv@...il.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
linux-kernel@...r.kernel.org
Subject: [RFC net-next 3/4] net: dsa: yt921x: Add port police support
Enable rate meter ability and support limiting the rate of incoming
traffic.
Signed-off-by: David Yang <mmyangfl@...il.com>
---
drivers/net/dsa/yt921x.c | 255 ++++++++++++++++++++++++++++++++++++++-
drivers/net/dsa/yt921x.h | 56 +++++++++
2 files changed, 310 insertions(+), 1 deletion(-)
diff --git a/drivers/net/dsa/yt921x.c b/drivers/net/dsa/yt921x.c
index 6d03888b6743..f1465c4d9b1b 100644
--- a/drivers/net/dsa/yt921x.c
+++ b/drivers/net/dsa/yt921x.c
@@ -356,6 +356,14 @@ yt921x_longreg_clear_bits(struct yt921x_priv *priv, u32 reg, const u32 *masks,
return yt921x_longreg_write(priv, reg, vs, span);
}
+static void u32a_update_u64(u32 *arr, u64 mask, u64 val)
+{
+ arr[0] &= ~((u32)mask);
+ arr[1] &= ~((u32)(mask >> 32));
+ arr[0] |= (u32)val;
+ arr[1] |= (u32)(val >> 32);
+}
+
static int yt921x_reg_mdio_read(void *context, u32 reg, u32 *valp)
{
struct yt921x_reg_mdio *mdio = context;
@@ -1047,6 +1055,13 @@ 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)
{
@@ -1078,6 +1093,204 @@ 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 */
+#define ldexpi(v, e) ({ \
+ __auto_type _v = (v); \
+ __auto_type _e = (e); \
+ _e >= 0 ? _v << _e : _v >> -_e; \
+})
+
+/* slot (ns) * rate (/s) / 10^9 (ns/s) = 2^C * token * 4^unit */
+#define rate2token(rate, unit, slot_ns, C) \
+ ((u32)(ldexpi((slot_ns) * (rate), \
+ -(2 * (unit) + (C) + YT921X_TOKEN_RATE_C)) / 1000000000))
+#define token2rate(token, unit, slot_ns, C) \
+ (ldexpi(1000000000 * (u64)(token), \
+ 2 * (unit) + (C) + YT921X_TOKEN_RATE_C) / (slot_ns))
+
+/* burst = 2^C * token * 4^unit */
+#define burst2token(burst, unit, C) ((u32)ldexpi((burst), -(2 * (unit) + (C))))
+#define token2burst(token, unit, C) ldexpi((u64)(token), 2 * (unit) + (C))
+
+struct yt921x_meter {
+ u32 cir;
+ u32 cbs;
+ u32 ebs;
+ int unit;
+};
+
+#define YT921X_METER_PKT_MODE BIT(0)
+#define YT921X_METER_SINGLE_BUCKET BIT(1)
+
+static struct yt921x_meter
+yt921x_meter_tfm(struct yt921x_priv *priv, int port, unsigned int slot_ns,
+ u64 rate, u64 burst, unsigned int flags,
+ u32 cir_max, u32 cbs_max, int unit_max)
+{
+ const int C = flags & YT921X_METER_PKT_MODE ? YT921X_TOKEN_PKT_C :
+ YT921X_TOKEN_BYTE_C;
+ struct device *dev = to_device(priv);
+ struct yt921x_meter meter;
+ bool distorted;
+ u64 burst_est;
+ u64 burst_max;
+ u64 rate_max;
+
+ meter.unit = unit_max;
+ rate_max = token2rate(cir_max, meter.unit, slot_ns, C);
+ burst_max = token2burst(cbs_max, meter.unit, C);
+
+ /* clamp rate and burst */
+ if (rate > rate_max || burst > burst_max) {
+ dev_warn(dev,
+ "rate %llu, burst %llu too high, max is %llu, %llu, clamping...\n",
+ rate, burst, rate_max, burst_max);
+
+ if (rate > rate_max)
+ rate = rate_max;
+ if (burst > burst_max)
+ burst = burst_max;
+
+ burst_est = slot_ns * rate / 1000000000;
+ } else {
+ u64 burst_sug;
+
+ burst_est = slot_ns * rate / 1000000000;
+ burst_sug = burst_est;
+ if (flags & YT921X_METER_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 using burst at least %llu to match rate %llu\n",
+ burst_sug, rate);
+
+ /* select unit */
+ for (; meter.unit > 0; meter.unit--) {
+ if (rate > (rate_max >> 2) || burst > (burst_max >> 2))
+ break;
+ rate_max >>= 2;
+ burst_max >>= 2;
+ }
+ }
+
+ /* calculate information rate and bucket size */
+ distorted = false;
+ meter.cir = rate2token(rate, meter.unit, slot_ns, C);
+ if (!meter.cir) {
+ distorted = true;
+ meter.cir = 1;
+ } else if (meter.cir > cir_max) {
+ WARN_ON(1);
+ meter.cir = cir_max;
+ }
+ meter.cbs = burst2token(burst, meter.unit, C);
+ if (!meter.cbs) {
+ distorted = true;
+ meter.cbs = 1;
+ } else if (meter.cbs > cbs_max) {
+ WARN_ON(1);
+ meter.cbs = cbs_max;
+ }
+ if (distorted)
+ dev_warn(dev,
+ "Have to increase rate %llu, burst %llu to %llu, %llu\n",
+ rate, burst,
+ token2rate(meter.cir, meter.unit, slot_ns, C),
+ token2burst(meter.cbs, meter.unit, C));
+
+ /* cut ebs */
+ meter.ebs = 0;
+ if (!(flags & YT921X_METER_SINGLE_BUCKET)) {
+ /* we don't have a chance to adjust rate when MTU is changed */
+ if (flags & YT921X_METER_PKT_MODE)
+ burst_est++;
+ else
+ burst_est += YT921X_FRAME_SIZE_MAX;
+
+ if (burst_est < burst) {
+ u32 pbs = meter.cbs;
+
+ meter.cbs = burst2token(burst_est, meter.unit, C);
+ if (!meter.cbs) {
+ meter.cbs = 1;
+ } else if (meter.cbs > cbs_max) {
+ WARN_ON(1);
+ meter.cbs = cbs_max;
+ }
+
+ if (pbs > meter.cbs)
+ meter.ebs = pbs - meter.cbs;
+ }
+ }
+
+ dev_dbg(dev,
+ "slot %u ns, rate %llu, burst %llu -> unit %d, cir %u, cbs %u, ebs %u\n",
+ slot_ns, rate, burst,
+ meter.unit, meter.cir, meter.cbs, meter.ebs);
+
+ return meter;
+}
+
+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)
+ print_port_err(dev, port, res, "delete policer on");
+}
+
+static int
+yt921x_dsa_port_policer_add(struct dsa_switch *ds, int port,
+ struct dsa_mall_policer_tc_entry *policer)
+{
+ struct yt921x_priv *priv = to_yt921x_priv(ds);
+ u32 ctrls[YT921X_METER_CTRL_S];
+ struct yt921x_meter meter;
+ u64 burst;
+ u64 rate;
+ u32 ctrl;
+ int res;
+
+ rate = policer->rate_bytes_per_sec;
+ burst = policer->burst;
+ meter = yt921x_meter_tfm(priv, port, priv->meter_slot_ns, rate, burst,
+ 0, YT921X_METER_RATE_MAX,
+ YT921X_METER_BURST_MAX, YT921X_METER_UNIT_MAX);
+
+ mutex_lock(&priv->reg_lock);
+ ctrl = YT921X_PORT_METER_ID(port) | YT921X_PORT_METER_EN;
+ res = yt921x_reg_write(priv, YT921X_PORTn_METER(port), ctrl);
+ if (res)
+ goto end;
+
+ ctrls[0] = 0;
+ ctrls[1] = YT921X_METER_CTRLb_CIR(meter.cir);
+ ctrls[2] = YT921X_METER_CTRLc_UNIT(meter.unit) |
+ YT921X_METER_CTRLc_DROP_R |
+ YT921X_METER_CTRLc_TOKEN_OVERFLOW_EN |
+ YT921X_METER_CTRLc_METER_EN;
+ u32a_update_u64(&ctrls[0], YT921X_METER_CTRLab_EBS_M,
+ YT921X_METER_CTRLab_EBS(meter.ebs));
+ u32a_update_u64(&ctrls[1], YT921X_METER_CTRLbc_CBS_M,
+ YT921X_METER_CTRLbc_CBS(meter.cbs));
+ res = yt921x_longreg_write(priv,
+ YT921X_METERn_CTRL(port + YT921X_METER_NUM),
+ ctrls, YT921X_METER_CTRL_S);
+end:
+ mutex_unlock(&priv->reg_lock);
+
+ return res;
+}
+
static int
yt921x_mirror_del(struct yt921x_priv *priv, int port, bool ingress)
{
@@ -3040,6 +3253,7 @@ 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);
@@ -3074,12 +3288,27 @@ 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;
}
@@ -3202,6 +3431,23 @@ 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;
@@ -3248,7 +3494,7 @@ 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;
@@ -3257,6 +3503,10 @@ 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)
@@ -3348,6 +3598,9 @@ 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 361470582687..129073ed3a4b 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
@@ -466,6 +472,44 @@ 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_CTRL_S 3
+#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)
@@ -509,6 +553,16 @@ 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
+/* for VLAN only, not including port meters */
+#define YT921X_METER_NUM 64
+#define YT921X_METER_SLOT_MIN 80
+#define YT921X_METER_UNIT_MAX ((1 << 3) - 1)
+#define YT921X_METER_BURST_MAX ((1 << 16) - 1)
+#define YT921X_METER_RATE_MAX ((1 << 18) - 1)
+
#define YT921X_LAG_NUM 2
#define YT921X_LAG_PORT_NUM 4
@@ -603,8 +657,10 @@ 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;
+ u8 cycle_ns;
/* protect the access to the switch registers */
struct mutex reg_lock;
--
2.51.0
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