netdev - [PATCH net-next 2/6] net: macb: Integrate ENST timing parameters and hardware unit conversion

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Message-ID: <20250722154111.1871292-3-vineeth.karumanchi@amd.com>
Date: Tue, 22 Jul 2025 21:11:07 +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 2/6] net: macb: Integrate ENST timing parameters and hardware unit conversion

Add Enhanced Network Scheduling and Timing (ENST) support to
queue infrastructure with speed-dependent timing calculations for
precise gate control.

Hardware timing unit conversion:
- Timing values programmed as hardware units based on link speed
- Conversion formula: time_bytes = time_ns / divisor
- Speed-specific divisors:
  * 1 Gbps:   divisor = 8
  * 100 Mbps: divisor = 80
  * 10 Mbps:  divisor = 800

Infrastructure changes:
- Extend macb_queue structure with ENST timing control registers
- Add queue_enst_configs structure for per-entry TC configuration storage
- Map ENST register offsets into existing queue management framework
- Define ENST_NS_TO_HW_UNITS() macro for automatic speed-based conversion

This enables hardware-native timing programming while abstracting the
speed-dependent conversions

Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@....com>
---
 drivers/net/ethernet/cadence/macb.h      | 32 ++++++++++++++++++++++++
 drivers/net/ethernet/cadence/macb_main.c |  6 +++++
 2 files changed, 38 insertions(+)

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index e456ac65d6c6..ef3995564c5c 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -857,6 +857,16 @@
 
 #define MACB_READ_NSR(bp)	macb_readl(bp, NSR)
 
+/* ENST macros*/
+#define ENST_NS_TO_HW_UNITS(ns, speed_mbps) \
+		DIV_ROUND_UP((ns) * (speed_mbps), (ENST_TIME_GRANULARITY_NS * 1000))
+
+#define ENST_MAX_HW_INTERVAL(speed_mbps) \
+		DIV_ROUND_UP(GENMASK(GEM_ON_TIME_SIZE - 1, 0) * ENST_TIME_GRANULARITY_NS * 1000,\
+		(speed_mbps))
+
+#define ENST_MAX_START_TIME_SEC GENMASK(GEM_START_TIME_SEC_SIZE - 1, 0)
+
 /* struct macb_dma_desc - Hardware DMA descriptor
  * @addr: DMA address of data buffer
  * @ctrl: Control and status bits
@@ -1262,6 +1272,11 @@ 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;
@@ -1450,4 +1465,21 @@ struct macb_platform_data {
 	struct clk	*hclk;
 };
 
+/**
+ * struct queue_enst_configs - Configuration for Enhanced Scheduled Traffic (ENST) queue
+ * @queue_id:         Identifier for the queue
+ * @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
+ *
+ * This structure holds the configuration parameters for an ENST queue,
+ * used to control time-based transmission scheduling in the MACB driver.
+ */
+struct queue_enst_configs {
+	u8 queue_id;
+	u32 start_time_mask;
+	u32 on_time_bytes;
+	u32 off_time_bytes;
+};
+
 #endif /* _MACB_H */
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index ce95fad8cedd..ff87d3e1d8a0 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -4305,6 +4305,9 @@ static int macb_init(struct platform_device *pdev)
 			queue->TBQP = GEM_TBQP(hw_q - 1);
 			queue->RBQP = GEM_RBQP(hw_q - 1);
 			queue->RBQS = GEM_RBQS(hw_q - 1);
+			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);
 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
 			if (bp->hw_dma_cap & HW_DMA_CAP_64B) {
 				queue->TBQPH = GEM_TBQPH(hw_q - 1);
@@ -4319,6 +4322,9 @@ static int macb_init(struct platform_device *pdev)
 			queue->IMR  = MACB_IMR;
 			queue->TBQP = MACB_TBQP;
 			queue->RBQP = MACB_RBQP;
+			queue->ENST_START_TIME = GEM_ENST_START_TIME(0);
+			queue->ENST_ON_TIME = GEM_ENST_ON_TIME(0);
+			queue->ENST_OFF_TIME = GEM_ENST_OFF_TIME(0);
 #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
 			if (bp->hw_dma_cap & HW_DMA_CAP_64B) {
 				queue->TBQPH = MACB_TBQPH;
-- 
2.34.1