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Message-ID: <20250722154111.1871292-4-vineeth.karumanchi@amd.com>
Date: Tue, 22 Jul 2025 21:11:08 +0530
From: Vineeth Karumanchi <vineeth.karumanchi@....com>
To: <nicolas.ferre@...rochip.com>, <claudiu.beznea@...on.dev>,
<andrew+netdev@...n.ch>, <davem@...emloft.net>, <edumazet@...gle.com>,
<kuba@...nel.org>, <pabeni@...hat.com>
CC: <git@....com>, <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<vineeth.karumanchi@....com>
Subject: [PATCH net-next 3/6] net: macb: Add IEEE 802.1Qbv TAPRIO REPLACE command offload support
Implement Time-Aware Traffic Scheduling (TAPRIO) hardware offload for
"tc qdisc replace" operations, enabling IEEE 802.1Qbv compliant gate
scheduling on Cadence MACB/GEM controllers.
Parameter validation checks performed:
- Queue count bounds checking (1 < queues <= MACB_MAX_QUEUES)
- TC entry limit validation against available hardware queues
- Base time non-negativity enforcement
- Speed-adaptive timing constraint verification
- Cycle time vs. total gate time consistency checks
- Single-queue gate mask enforcement per scheduling entry
Hardware programming sequence:
- GEM doesn't support changing register values if ENST is running,
hence disable ENST before programming
- Atomic timing register configuration (START_TIME, ON_TIME, OFF_TIME)
- Enable the configured queues via ENST_CONTROL register
This implementation ensures deterministic gate scheduling while preventing
invalid configurations.
Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@....com>
---
drivers/net/ethernet/cadence/macb_main.c | 155 +++++++++++++++++++++++
1 file changed, 155 insertions(+)
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index ff87d3e1d8a0..4518b59168d5 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -36,6 +36,7 @@
#include <linux/reset.h>
#include <linux/firmware/xlnx-zynqmp.h>
#include <linux/inetdevice.h>
+#include <net/pkt_sched.h>
#include "macb.h"
/* This structure is only used for MACB on SiFive FU540 devices */
@@ -4084,6 +4085,160 @@ static void macb_restore_features(struct macb *bp)
macb_set_rxflow_feature(bp, features);
}
+static int macb_taprio_setup_replace(struct net_device *ndev,
+ struct tc_taprio_qopt_offload *conf)
+{
+ u64 total_on_time = 0, start_time_sec = 0, start_time = conf->base_time;
+ struct queue_enst_configs *enst_queue;
+ u32 configured_queues = 0, speed = 0;
+ struct tc_taprio_sched_entry *entry;
+ struct macb *bp = netdev_priv(ndev);
+ struct ethtool_link_ksettings kset;
+ struct macb_queue *queue;
+ unsigned long flags;
+ int err = 0, i;
+
+ /* Validate queue configuration */
+ if (bp->num_queues < 1 || bp->num_queues > MACB_MAX_QUEUES) {
+ netdev_err(ndev, "Invalid number of queues: %d\n", bp->num_queues);
+ return -EINVAL;
+ }
+
+ if (conf->num_entries > bp->num_queues) {
+ netdev_err(ndev, "Too many TAPRIO entries: %lu > %d queues\n",
+ conf->num_entries, bp->num_queues);
+ return -EINVAL;
+ }
+
+ if (start_time < 0) {
+ netdev_err(ndev, "Invalid base_time: must be 0 or positive, got %lld\n",
+ conf->base_time);
+ return -ERANGE;
+ }
+
+ /* Get the current link speed */
+ err = phylink_ethtool_ksettings_get(bp->phylink, &kset);
+ if (unlikely(err)) {
+ netdev_err(ndev, "Failed to get link settings: %d\n", err);
+ return err;
+ }
+
+ speed = kset.base.speed;
+ if (unlikely(speed <= 0)) {
+ netdev_err(ndev, "Invalid speed: %d\n", speed);
+ return -EINVAL;
+ }
+
+ enst_queue = kcalloc(conf->num_entries, sizeof(*enst_queue), GFP_KERNEL);
+ if (!enst_queue)
+ return -ENOMEM;
+
+ /* Pre-validate all entries before making any hardware changes */
+ for (i = 0; i < conf->num_entries; i++) {
+ entry = &conf->entries[i];
+
+ if (entry->command != TC_TAPRIO_CMD_SET_GATES) {
+ netdev_err(ndev, "Entry %d: unsupported command %d\n",
+ i, entry->command);
+ err = -EOPNOTSUPP;
+ goto cleanup;
+ }
+
+ /* Validate gate_mask: must be nonzero, single queue, and within range */
+ if (!is_power_of_2(entry->gate_mask)) {
+ netdev_err(ndev, "Entry %d: gate_mask 0x%x is not a power of 2 (only one queue per entry allowed)\n",
+ i, entry->gate_mask);
+ err = -EINVAL;
+ goto cleanup;
+ }
+
+ /* gate_mask must not select queues outside the valid queue_mask */
+ if (entry->gate_mask & ~bp->queue_mask) {
+ netdev_err(ndev, "Entry %d: gate_mask 0x%x exceeds queue range (max_queues=%d)\n",
+ i, entry->gate_mask, bp->num_queues);
+ err = -EINVAL;
+ goto cleanup;
+ }
+
+ /* Check for start time limits */
+ start_time_sec = div_u64(start_time, NSEC_PER_SEC);
+ if (start_time_sec > ENST_MAX_START_TIME_SEC) {
+ netdev_err(ndev, "Entry %d: Start time %llu s exceeds hardware limit\n",
+ i, start_time_sec);
+ err = -ERANGE;
+ goto cleanup;
+ }
+
+ /* Check for on time limit*/
+ if (entry->interval > ENST_MAX_HW_INTERVAL(speed)) {
+ netdev_err(ndev, "Entry %d: interval %u ns exceeds hardware limit %lu ns\n",
+ i, entry->interval, ENST_MAX_HW_INTERVAL(speed));
+ err = -ERANGE;
+ goto cleanup;
+ }
+
+ /* Check for off time limit*/
+ if ((conf->cycle_time - entry->interval) > ENST_MAX_HW_INTERVAL(speed)) {
+ netdev_err(ndev, "Entry %d: off_time %llu ns exceeds hardware limit %lu ns\n",
+ i, conf->cycle_time - entry->interval,
+ ENST_MAX_HW_INTERVAL(speed));
+ err = -ERANGE;
+ goto cleanup;
+ }
+
+ enst_queue[i].queue_id = order_base_2(entry->gate_mask);
+ enst_queue[i].start_time_mask =
+ (start_time_sec << GEM_START_TIME_SEC_OFFSET) |
+ (start_time % NSEC_PER_SEC);
+ enst_queue[i].on_time_bytes =
+ ENST_NS_TO_HW_UNITS(entry->interval, speed);
+ enst_queue[i].off_time_bytes =
+ ENST_NS_TO_HW_UNITS(conf->cycle_time - entry->interval, speed);
+
+ configured_queues |= entry->gate_mask;
+ total_on_time += entry->interval;
+ start_time += entry->interval;
+ }
+
+ /* Check total interval doesn't exceed cycle time */
+ if (total_on_time > conf->cycle_time) {
+ netdev_err(ndev, "Total ON %llu ns exceeds cycle time %llu ns\n",
+ total_on_time, conf->cycle_time);
+ err = -EINVAL;
+ goto cleanup;
+ }
+
+ netdev_dbg(ndev, "TAPRIO setup: %lu entries, base_time=%lld ns, cycle_time=%llu ns\n",
+ conf->num_entries, conf->base_time, conf->cycle_time);
+
+ /* All validations passed - proceed with hardware configuration */
+ spin_lock_irqsave(&bp->lock, flags);
+
+ /* Disable ENST queues if running before configuring */
+ if (gem_readl(bp, ENST_CONTROL))
+ gem_writel(bp, ENST_CONTROL,
+ GENMASK(bp->num_queues - 1, 0) << GEM_ENST_DISABLE_QUEUE_OFFSET);
+
+ for (i = 0; i < conf->num_entries; i++) {
+ queue = &bp->queues[enst_queue[i].queue_id];
+ /* Configure queue timing registers */
+ queue_writel(queue, ENST_START_TIME, enst_queue[i].start_time_mask);
+ queue_writel(queue, ENST_ON_TIME, enst_queue[i].on_time_bytes);
+ queue_writel(queue, ENST_OFF_TIME, enst_queue[i].off_time_bytes);
+ }
+
+ /* Enable ENST for all configured queues in one write */
+ gem_writel(bp, ENST_CONTROL, configured_queues);
+ spin_unlock_irqrestore(&bp->lock, flags);
+
+ netdev_info(ndev, "TAPRIO configuration completed successfully: %lu entries, %d queues configured\n",
+ conf->num_entries, hweight32(configured_queues));
+
+cleanup:
+ kfree(enst_queue);
+ return err;
+}
+
static const struct net_device_ops macb_netdev_ops = {
.ndo_open = macb_open,
.ndo_stop = macb_close,
--
2.34.1
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