[PATCH net-next v5 2/2] net: ti: icssg-prueth: Add ethtool ops for Frame Preemption MAC Merge

Meghana Malladi
2026-04-30T11:17:41Z

From: MD Danish Anwar <danishanwar@ti.com>

Add driver support for viewing and changing the MAC Merge sublayer
parameters via ethtool ops: .set_mm(), .get_mm() and .get_mm_stats().

The minimum size of non-final mPacket fragments supported by the firmware
without leading errors is 64 Bytes (including FCS). Verify time bounded to
1-128 ms per 802.3-2018 clause 30.14.1.6. Add a check to ensure
user passed tx_min_frag_size argument via ethtool, honors this.
Add pa stats registers to check statistics for preemption, which can be
dumped using ethtool ops.

Fix emac_get_stat_by_name() to return u64 instead of int and return 0 on
error instead of -EINVAL. This prevents invalid stat lookups from corrupting
output stats with signed error codes cast to u64. Error conditions are still
logged via netdev_err().

Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
Signed-off-by: Meghana Malladi <m-malladi@ti.com>
---

Changes from v4(v5-v4):
- Fix the naming conventiion for icssg_qos_frag_size_min_to_add()
- Change the logic to include FCS while validating and accepting
values from the userspace
All the above changes are addressed as part of Vladimir Oltean <vladimir.oltean@nxp.com>
comments for this patch
- Handle all verify_status values in emac_get_mm() based on what
all states are supported by the firmware.
This change is addressed based on AI-generated review and highlighted by
Simon Horman <horms@kernel.org>

drivers/net/ethernet/ti/icssg/icssg_ethtool.c | 107 +++++++++++++++++-
drivers/net/ethernet/ti/icssg/icssg_prueth.h | 7 +-
drivers/net/ethernet/ti/icssg/icssg_qos.h | 38 +++++++
drivers/net/ethernet/ti/icssg/icssg_stats.c | 5 +-
drivers/net/ethernet/ti/icssg/icssg_stats.h | 5 +
.../net/ethernet/ti/icssg/icssg_switch_map.h | 5 +
6 files changed, 160 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/ti/icssg/icssg_ethtool.c b/drivers/net/ethernet/ti/icssg/icssg_ethtool.c
index b715af21d23ac..6a08c40adde54 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_ethtool.c
+++ b/drivers/net/ethernet/ti/icssg/icssg_ethtool.c
@@ -6,7 +6,6 @@
*/

#include "icssg_prueth.h"
-#include "icssg_stats.h"

static void emac_get_drvinfo(struct net_device *ndev,
struct ethtool_drvinfo *info)
@@ -294,6 +293,109 @@ static int emac_set_per_queue_coalesce(struct net_device *ndev, u32 queue,
return 0;
}

+static int emac_get_mm(struct net_device *ndev, struct ethtool_mm_state *state)
+{
+ struct prueth_emac *emac = netdev_priv(ndev);
+ struct prueth_qos_iet *iet = &emac->qos.iet;
+ enum icssg_ietfpe_verify_states verify_status;
+
+ if (emac->is_sr1)
+ return -EOPNOTSUPP;
+
+ mutex_lock(&iet->fpe_lock);
+ state->tx_enabled = iet->fpe_enabled;
+ state->tx_min_frag_size = iet->tx_min_frag_size - ETH_FCS_LEN;
+ state->tx_active = iet->fpe_active;
+ state->verify_enabled = iet->mac_verify_configure;
+ state->verify_time = iet->verify_time_ms;
+ verify_status = iet->verify_status;
+ mutex_unlock(&iet->fpe_lock);
+
+ state->pmac_enabled = true;
+ /* 64Bytes is the minimum fragment size supported
+ * by the firmware. <64B leads to min frame errors
+ */
+ state->rx_min_frag_size = 64;
+
+ switch (verify_status) {
+ case ICSSG_IETFPE_STATE_DISABLED:
+ state->verify_status = ETHTOOL_MM_VERIFY_STATUS_DISABLED;
+ break;
+ case ICSSG_IETFPE_STATE_INITIAL:
+ state->verify_status = ETHTOOL_MM_VERIFY_STATUS_INITIAL;
+ break;
+ case ICSSG_IETFPE_STATE_VERIFYING:
+ state->verify_status = ETHTOOL_MM_VERIFY_STATUS_VERIFYING;
+ break;
+ case ICSSG_IETFPE_STATE_SUCCEEDED:
+ state->verify_status = ETHTOOL_MM_VERIFY_STATUS_SUCCEEDED;
+ break;
+ case ICSSG_IETFPE_STATE_FAILED:
+ state->verify_status = ETHTOOL_MM_VERIFY_STATUS_FAILED;
+ break;
+ default:
+ state->verify_status = ETHTOOL_MM_VERIFY_STATUS_UNKNOWN;
+ break;
+ }
+
+ /* 802.3-2018 clause 30.14.1.6, says that the aMACMergeVerifyTime
+ * variable has a range between 1 and 128 ms inclusive. Limit to that.
+ */
+ state->max_verify_time = ETHTOOL_MM_MAX_VERIFY_TIME_MS;
+
+ return 0;
+}
+
+static int emac_set_mm(struct net_device *ndev, struct ethtool_mm_cfg *cfg,
+ struct netlink_ext_ack *extack)
+{
+ struct prueth_emac *emac = netdev_priv(ndev);
+ struct prueth_qos_iet *iet = &emac->qos.iet;
+ int err;
+
+ if (emac->is_sr1)
+ return -EOPNOTSUPP;
+
+ if (!cfg->pmac_enabled)
+ NL_SET_ERR_MSG_MOD(extack, "preemptible MAC is always enabled");
+
+ err = icssg_qos_validate_tx_min_frag_size(cfg->tx_min_frag_size, extack);
+ if (err)
+ return err;
+
+ err = icssg_qos_validate_verify_time(cfg->verify_time, extack);
+ if (err)
+ return err;
+
+ mutex_lock(&iet->fpe_lock);
+ iet->verify_time_ms = cfg->verify_time;
+ iet->tx_min_frag_size = cfg->tx_min_frag_size + ETH_FCS_LEN;
+ iet->fpe_enabled = cfg->tx_enabled;
+ iet->mac_verify_configure = cfg->verify_enabled;
+ icssg_config_ietfpe(emac, cfg->tx_enabled);
+ mutex_unlock(&iet->fpe_lock);
+
+ return err;
+}
+
+static void emac_get_mm_stats(struct net_device *ndev,
+ struct ethtool_mm_stats *s)
+{
+ struct prueth_emac *emac = netdev_priv(ndev);
+
+ if (emac->is_sr1)
+ return;
+
+ if (!emac->prueth->pa_stats)
+ return;
+
+ s->MACMergeFrameAssOkCount = emac_get_stat_by_name(emac, "FW_PREEMPT_ASSEMBLY_OK");
+ s->MACMergeFrameAssErrorCount = emac_get_stat_by_name(emac, "FW_PREEMPT_ASSEMBLY_ERR");
+ s->MACMergeFragCountRx = emac_get_stat_by_name(emac, "FW_PREEMPT_FRAG_CNT_RX");
+ s->MACMergeFragCountTx = emac_get_stat_by_name(emac, "FW_PREEMPT_FRAG_CNT_TX");
+ s->MACMergeFrameSmdErrorCount = emac_get_stat_by_name(emac, "FW_PREEMPT_BAD_FRAG");
+}
+
const struct ethtool_ops icssg_ethtool_ops = {
.get_drvinfo = emac_get_drvinfo,
.get_msglevel = emac_get_msglevel,
@@ -317,5 +419,8 @@ const struct ethtool_ops icssg_ethtool_ops = {
.set_eee = emac_set_eee,
.nway_reset = emac_nway_reset,
.get_rmon_stats = emac_get_rmon_stats,
+ .get_mm = emac_get_mm,
+ .set_mm = emac_set_mm,
+ .get_mm_stats = emac_get_mm_stats,
};
EXPORT_SYMBOL_GPL(icssg_ethtool_ops);
diff --git a/drivers/net/ethernet/ti/icssg/icssg_prueth.h b/drivers/net/ethernet/ti/icssg/icssg_prueth.h
index 85f7017d2c8e7..61320c252bec2 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_prueth.h
+++ b/drivers/net/ethernet/ti/icssg/icssg_prueth.h
@@ -45,6 +45,7 @@
#include "icss_iep.h"
#include "icssg_switch_map.h"
#include "icssg_qos.h"
+#include "icssg_stats.h"

#define PRUETH_MAX_MTU (2000 - ETH_HLEN - ETH_FCS_LEN)
#define PRUETH_MIN_PKT_SIZE (VLAN_ETH_ZLEN)
@@ -58,8 +59,8 @@

#define ICSSG_MAX_RFLOWS 8 /* per slice */

-#define ICSSG_NUM_PA_STATS 32
-#define ICSSG_NUM_MIIG_STATS 60
+#define ICSSG_NUM_PA_STATS ARRAY_SIZE(icssg_all_pa_stats)
+#define ICSSG_NUM_MIIG_STATS ARRAY_SIZE(icssg_all_miig_stats)
/* Number of ICSSG related stats */
#define ICSSG_NUM_STATS (ICSSG_NUM_MIIG_STATS + ICSSG_NUM_PA_STATS)
#define ICSSG_NUM_STANDARD_STATS 31
@@ -460,7 +461,7 @@ int emac_fdb_flow_id_updated(struct prueth_emac *emac);

void icssg_stats_work_handler(struct work_struct *work);
void emac_update_hardware_stats(struct prueth_emac *emac);
-int emac_get_stat_by_name(struct prueth_emac *emac, char *stat_name);
+u64 emac_get_stat_by_name(struct prueth_emac *emac, char *stat_name);

/* Common functions */
void prueth_cleanup_rx_chns(struct prueth_emac *emac,
diff --git a/drivers/net/ethernet/ti/icssg/icssg_qos.h b/drivers/net/ethernet/ti/icssg/icssg_qos.h
index 083f248c557de..104910516d966 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_qos.h
+++ b/drivers/net/ethernet/ti/icssg/icssg_qos.h
@@ -65,4 +65,42 @@ void icssg_qos_link_state_update(struct net_device *ndev);
int icssg_qos_ndo_setup_tc(struct net_device *ndev, enum tc_setup_type type,
void *type_data);
void icssg_config_ietfpe(struct prueth_emac *emac, bool enable);
+static inline int icssg_qos_validate_tx_min_frag_size(u32 min_frag_size,
+ struct netlink_ext_ack *extack)
+{
+ /* Firmware takes min_frag_size including FCS length */
+ min_frag_size += ETH_FCS_LEN;
+
+ /* The minimum size of the non-final mPacket supported
+ * by the firmware is 64B and multiples of 64B.
+ */
+ if (min_frag_size < 64) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "tx_min_frag_size must be at least 64 bytes");
+ return -EINVAL;
+ }
+
+ if (min_frag_size % (ETH_ZLEN + ETH_FCS_LEN)) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "tx_min_frag_size must be a multiple of 64 bytes");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static inline int icssg_qos_validate_verify_time(u32 verify_time_ms,
+ struct netlink_ext_ack *extack)
+{
+ /* 802.3-2018 clause 30.14.1.6: aMACMergeVerifyTime must be
+ * between 1 and 128 ms inclusive
+ */
+ if (verify_time_ms < 1 || verify_time_ms > 128) {
+ NL_SET_ERR_MSG_MOD(extack,
+ "verify_time must be between 1 and 128 ms");
+ return -EINVAL;
+ }
+
+ return 0;
+}
#endif /* __NET_TI_ICSSG_QOS_H */
diff --git a/drivers/net/ethernet/ti/icssg/icssg_stats.c b/drivers/net/ethernet/ti/icssg/icssg_stats.c
index 7159baa0155cf..950d58d8183eb 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_stats.c
+++ b/drivers/net/ethernet/ti/icssg/icssg_stats.c
@@ -6,7 +6,6 @@
*/

#include "icssg_prueth.h"
-#include "icssg_stats.h"
#include <linux/regmap.h>

#define ICSSG_TX_PACKET_OFFSET 0xA0
@@ -74,7 +73,7 @@ void icssg_stats_work_handler(struct work_struct *work)
}
EXPORT_SYMBOL_GPL(icssg_stats_work_handler);

-int emac_get_stat_by_name(struct prueth_emac *emac, char *stat_name)
+u64 emac_get_stat_by_name(struct prueth_emac *emac, char *stat_name)
{
int i;

@@ -91,5 +90,5 @@ int emac_get_stat_by_name(struct prueth_emac *emac, char *stat_name)
}

netdev_err(emac->ndev, "Invalid stats %s\n", stat_name);
- return -EINVAL;
+ return 0;
}
diff --git a/drivers/net/ethernet/ti/icssg/icssg_stats.h b/drivers/net/ethernet/ti/icssg/icssg_stats.h
index 5ec0b38e0c67d..f35ae1b4f8460 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_stats.h
+++ b/drivers/net/ethernet/ti/icssg/icssg_stats.h
@@ -189,6 +189,11 @@ static const struct icssg_pa_stats icssg_all_pa_stats[] = {
ICSSG_PA_STATS(FW_INF_DROP_PRIOTAGGED),
ICSSG_PA_STATS(FW_INF_DROP_NOTAG),
ICSSG_PA_STATS(FW_INF_DROP_NOTMEMBER),
+ ICSSG_PA_STATS(FW_PREEMPT_BAD_FRAG),
+ ICSSG_PA_STATS(FW_PREEMPT_ASSEMBLY_ERR),
+ ICSSG_PA_STATS(FW_PREEMPT_FRAG_CNT_TX),
+ ICSSG_PA_STATS(FW_PREEMPT_ASSEMBLY_OK),
+ ICSSG_PA_STATS(FW_PREEMPT_FRAG_CNT_RX),
ICSSG_PA_STATS(FW_RX_EOF_SHORT_FRMERR),
ICSSG_PA_STATS(FW_RX_B0_DROP_EARLY_EOF),
ICSSG_PA_STATS(FW_TX_JUMBO_FRM_CUTOFF),
diff --git a/drivers/net/ethernet/ti/icssg/icssg_switch_map.h b/drivers/net/ethernet/ti/icssg/icssg_switch_map.h
index 7e053b8af3ece..855fd4ed0b3f6 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_switch_map.h
+++ b/drivers/net/ethernet/ti/icssg/icssg_switch_map.h
@@ -256,6 +256,11 @@
#define FW_INF_DROP_PRIOTAGGED 0x0148
#define FW_INF_DROP_NOTAG 0x0150
#define FW_INF_DROP_NOTMEMBER 0x0158
+#define FW_PREEMPT_BAD_FRAG 0x0160
+#define FW_PREEMPT_ASSEMBLY_ERR 0x0168
+#define FW_PREEMPT_FRAG_CNT_TX 0x0170
+#define FW_PREEMPT_ASSEMBLY_OK 0x0178
+#define FW_PREEMPT_FRAG_CNT_RX 0x0180
#define FW_RX_EOF_SHORT_FRMERR 0x0188
#define FW_RX_B0_DROP_EARLY_EOF 0x0190
#define FW_TX_JUMBO_FRM_CUTOFF 0x0198
--
2.43.0