Implement Time-Aware Traffic Scheduling (TAPRIO) offload support for Cadence MACB/GEM ethernet controllers to enable IEEE 802.1Qbv compliant time-sensitive networking (TSN) capabilities. Key Features: 1. Enhanced Scheduled Traffic (ENST) Register Management - Per-queue ENST registers: ENST_START_TIME, ENST_ON_TIME, ENST_OFF_TIME - Centralized control via ENST_CONTROL for gate enable/disable - Infrastructure enhancements: * Extended macb_queue structure with ENST timing control registers * Mapped ENST register offsets into queue management framework * Introduced macb_queue_enst_config for per-entry TC configuration - Timing conversion utility: * enst_ns_to_hw_units(): Converts nanoseconds to hardware units * Timing values are programmed as hardware units based on link speed * Conversion formula: time_bytes = time_ns / divisor * Speed-specific divisors: 1Gbps=8, 100Mbps=80, 10Mbps=800 - Hardware limit utility: * enst_max_hw_interval(): Returns max interval for given speed 2. TAPRIO Configuration via "tc qdisc replace" - macb_taprio_setup_replace(): Configures TAPRIO hardware offload - Parameter validation checks performed: * 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 - Programming sequence: * GEM doesn't support changing ENST registers if ENST is enabled, hence disable ENST before programming * Atomic timing register configuration (START_TIME, ON_TIME, OFF_TIME) * Enable queues via ENST_CONTROL 3. TAPRIO Cleanup via "tc qdisc destroy" - macb_taprio_destroy(): Safely removes TAPRIO configuration - Restores default queue behavior - Cleanup steps: * Reset TC state * Disable ENST * Clear timing registers * Ensure atomic updates with locking 4. Traffic Control Offload Infrastructure - macb_setup_taprio(): TAPRIO command dispatcher * Verifies hardware support * Handles runtime suspend state - macb_setup_tc(): TC_SETUP_QDISC_TAPRIO entry point - Supports REPLACE and DESTROY operations Tested on Xilinx Versal platforms with QBV-capable MACB controllers. Signed-off-by: Vineeth Karumanchi --- v2: - Merged patches as per the suggestion - Removed GEM_ENST_DISABLE_QUEUE() and GEM_ENST_ENABLE_QUEUE() - Renamed queue_enst_config/macb_queue_enst_config, reordered elements to reduce padding - Moved queue->ENST_* params outside of if (hw_q) block for clarity - Cleaned up extra spaces and fixed indentation - Removed redundant num_queues check in macb_taprio_setup_replace() - leveraged scope_guard as per netdev coding style - Eliminated redundant ENST_CONTROL register read for ENST state - Used bp->queue_mask to generate ENST control mask - Applied standard queue iteration logic in macb_taprio_destroy() - Added HW offload support check in macb_taprio_setup() - Added runtime state check in macb_taprio_setup() v1: https://lore.kernel.org/netdev/20250722154111.1871292-1-vineeth.karumanchi@amd.com/ --- drivers/net/ethernet/cadence/macb.h | 66 +++++++ drivers/net/ethernet/cadence/macb_main.c | 223 +++++++++++++++++++++++ 2 files changed, 289 insertions(+) diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h index c9a5c8beb2fa..d1a98b45c92c 100644 --- a/drivers/net/ethernet/cadence/macb.h +++ b/drivers/net/ethernet/cadence/macb.h @@ -184,6 +184,13 @@ #define GEM_DCFG8 0x029C /* Design Config 8 */ #define GEM_DCFG10 0x02A4 /* Design Config 10 */ #define GEM_DCFG12 0x02AC /* Design Config 12 */ +#define GEM_ENST_START_TIME_Q0 0x0800 /* ENST Q0 start time */ +#define GEM_ENST_START_TIME_Q1 0x0804 /* ENST Q1 start time */ +#define GEM_ENST_ON_TIME_Q0 0x0820 /* ENST Q0 on time */ +#define GEM_ENST_ON_TIME_Q1 0x0824 /* ENST Q1 on time */ +#define GEM_ENST_OFF_TIME_Q0 0x0840 /* ENST Q0 off time */ +#define GEM_ENST_OFF_TIME_Q1 0x0844 /* ENST Q1 off time */ +#define GEM_ENST_CONTROL 0x0880 /* ENST control register */ #define GEM_USX_CONTROL 0x0A80 /* High speed PCS control register */ #define GEM_USX_STATUS 0x0A88 /* High speed PCS status register */ @@ -221,6 +228,13 @@ #define GEM_IDR(hw_q) (0x0620 + ((hw_q) << 2)) #define GEM_IMR(hw_q) (0x0640 + ((hw_q) << 2)) +#define GEM_ENST_START_TIME(hw_q) (0x0800 + ((hw_q) << 2)) +#define GEM_ENST_ON_TIME(hw_q) (0x0820 + ((hw_q) << 2)) +#define GEM_ENST_OFF_TIME(hw_q) (0x0840 + ((hw_q) << 2)) + +/* Bitfields in ENST_CONTROL */ +#define GEM_ENST_DISABLE_QUEUE_OFFSET 16 + /* Bitfields in NCR */ #define MACB_LB_OFFSET 0 /* reserved */ #define MACB_LB_SIZE 1 @@ -554,6 +568,23 @@ #define GEM_HIGH_SPEED_OFFSET 26 #define GEM_HIGH_SPEED_SIZE 1 +/* Bitfields in ENST_START_TIME_Qx. */ +#define GEM_START_TIME_SEC_OFFSET 30 +#define GEM_START_TIME_SEC_SIZE 2 +#define GEM_START_TIME_NSEC_OFFSET 0 +#define GEM_START_TIME_NSEC_SIZE 30 + +/* Bitfields in ENST_ON_TIME_Qx. */ +#define GEM_ON_TIME_OFFSET 0 +#define GEM_ON_TIME_SIZE 17 + +/* Bitfields in ENST_OFF_TIME_Qx. */ +#define GEM_OFF_TIME_OFFSET 0 +#define GEM_OFF_TIME_SIZE 17 + +/* Hardware ENST timing registers granularity */ +#define ENST_TIME_GRANULARITY_NS 8 + /* Bitfields in USX_CONTROL. */ #define GEM_USX_CTRL_SPEED_OFFSET 14 #define GEM_USX_CTRL_SPEED_SIZE 3 @@ -1219,6 +1250,11 @@ struct macb_queue { unsigned int RBQP; unsigned int RBQPH; + /* ENST register offsets for this queue */ + unsigned int ENST_START_TIME; + unsigned int ENST_ON_TIME; + unsigned int ENST_OFF_TIME; + /* Lock to protect tx_head and tx_tail */ spinlock_t tx_ptr_lock; unsigned int tx_head, tx_tail; @@ -1397,6 +1433,19 @@ static inline bool gem_has_ptp(struct macb *bp) return IS_ENABLED(CONFIG_MACB_USE_HWSTAMP) && (bp->caps & MACB_CAPS_GEM_HAS_PTP); } +/* ENST Helper functions */ +static inline u64 enst_ns_to_hw_units(size_t ns, u32 speed_mbps) +{ + return DIV_ROUND_UP((ns) * (speed_mbps), + (ENST_TIME_GRANULARITY_NS * 1000)); +} + +static inline u64 enst_max_hw_interval(u32 speed_mbps) +{ + return DIV_ROUND_UP(GENMASK(GEM_ON_TIME_SIZE - 1, 0) * + ENST_TIME_GRANULARITY_NS * 1000, (speed_mbps)); +} + /** * struct macb_platform_data - platform data for MACB Ethernet used for PCI registration * @pclk: platform clock @@ -1407,4 +1456,21 @@ struct macb_platform_data { struct clk *hclk; }; +/** + * struct macb_queue_enst_config - Configuration for Enhanced Scheduled Traffic + * @start_time_mask: Bitmask representing the start time for the queue + * @on_time_bytes: "on" time nsec expressed in bytes + * @off_time_bytes: "off" time nsec expressed in bytes + * @queue_id: Identifier for the queue + * + * This structure holds the configuration parameters for an ENST queue, + * used to control time-based transmission scheduling in the MACB driver. + */ +struct macb_queue_enst_config { + u32 start_time_mask; + u32 on_time_bytes; + u32 off_time_bytes; + u8 queue_id; +}; + #endif /* _MACB_H */ diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c index ce95fad8cedd..d4b9737f83eb 100644 --- a/drivers/net/ethernet/cadence/macb_main.c +++ b/drivers/net/ethernet/cadence/macb_main.c @@ -36,6 +36,7 @@ #include #include #include +#include #include "macb.h" /* This structure is only used for MACB on SiFive FU540 devices */ @@ -4084,6 +4085,223 @@ 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; + u32 configured_queues = 0, speed = 0, start_time_nsec; + struct macb_queue_enst_config *enst_queue; + struct tc_taprio_sched_entry *entry; + struct macb *bp = netdev_priv(ndev); + struct ethtool_link_ksettings kset; + struct macb_queue *queue; + size_t i; + int err; + + if (conf->num_entries > bp->num_queues) { + netdev_err(ndev, "Too many TAPRIO entries: %zu > %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 (unlikely(!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 %zu: 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 %zu: 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 %zu: 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 = start_time; + start_time_nsec = do_div(start_time_sec, NSEC_PER_SEC); + if (start_time_sec > GENMASK(GEM_START_TIME_SEC_SIZE - 1, 0)) { + netdev_err(ndev, "Entry %zu: 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 %zu: interval %u ns exceeds hardware limit %llu 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 %zu: off_time %llu ns exceeds hardware limit %llu 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; + 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: %zu 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 */ + scoped_guard(spinlock_irqsave, &bp->lock) { + /* Disable ENST queues if running before configuring */ + gem_writel(bp, ENST_CONTROL, + bp->queue_mask << 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); + } + + netdev_info(ndev, "TAPRIO configuration completed successfully: %zu entries, %d queues configured\n", + conf->num_entries, hweight32(configured_queues)); + +cleanup: + kfree(enst_queue); + return err; +} + +static void macb_taprio_destroy(struct net_device *ndev) +{ + struct macb *bp = netdev_priv(ndev); + struct macb_queue *queue; + u32 enst_disable_mask; + unsigned int q; + + netdev_reset_tc(ndev); + enst_disable_mask = bp->queue_mask << GEM_ENST_DISABLE_QUEUE_OFFSET; + + scoped_guard(spinlock_irqsave, &bp->lock) { + /* Single disable command for all queues */ + gem_writel(bp, ENST_CONTROL, enst_disable_mask); + + /* Clear all queue ENST registers in batch */ + for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) { + queue_writel(queue, ENST_START_TIME, 0); + queue_writel(queue, ENST_ON_TIME, 0); + queue_writel(queue, ENST_OFF_TIME, 0); + } + } + netdev_info(ndev, "TAPRIO destroy: All gates disabled\n"); +} + +static int macb_setup_taprio(struct net_device *ndev, + struct tc_taprio_qopt_offload *taprio) +{ + struct macb *bp = netdev_priv(ndev); + int err = 0; + + if (unlikely(!(ndev->hw_features & NETIF_F_HW_TC))) + return -EOPNOTSUPP; + + /* Check if Device is in runtime suspend */ + if (unlikely(pm_runtime_suspended(&bp->pdev->dev))) { + netdev_err(ndev, "Device is in runtime suspend\n"); + return -EOPNOTSUPP; + } + + switch (taprio->cmd) { + case TAPRIO_CMD_REPLACE: + err = macb_taprio_setup_replace(ndev, taprio); + break; + case TAPRIO_CMD_DESTROY: + macb_taprio_destroy(ndev); + break; + default: + err = -EOPNOTSUPP; + } + + return err; +} + +static int macb_setup_tc(struct net_device *dev, enum tc_setup_type type, + void *type_data) +{ + if (!dev || !type_data) + return -EINVAL; + + switch (type) { + case TC_SETUP_QDISC_TAPRIO: + return macb_setup_taprio(dev, type_data); + default: + return -EOPNOTSUPP; + } +} + static const struct net_device_ops macb_netdev_ops = { .ndo_open = macb_open, .ndo_stop = macb_close, @@ -4101,6 +4319,7 @@ static const struct net_device_ops macb_netdev_ops = { .ndo_features_check = macb_features_check, .ndo_hwtstamp_set = macb_hwtstamp_set, .ndo_hwtstamp_get = macb_hwtstamp_get, + .ndo_setup_tc = macb_setup_tc, }; /* Configure peripheral capabilities according to device tree @@ -4327,6 +4546,10 @@ static int macb_init(struct platform_device *pdev) #endif } + queue->ENST_START_TIME = GEM_ENST_START_TIME(hw_q); + queue->ENST_ON_TIME = GEM_ENST_ON_TIME(hw_q); + queue->ENST_OFF_TIME = GEM_ENST_OFF_TIME(hw_q); + /* get irq: here we use the linux queue index, not the hardware * queue index. the queue irq definitions in the device tree * must remove the optional gaps that could exist in the -- 2.34.1