[RFC PATCH 2/8] net: xilinx: tsn: Introduce TSN core driver skeleton

[Srinivas Neeli]

Introduce the initial skeleton for the AMD/Xilinx Time Sensitive
Networking (TSN) Ethernet IP driver. Adds the Kconfig entry
(CONFIG_XILINX_TSN), updates the Xilinx Ethernet Makefile,
and provides the base source file focused on device tree
parsing and clock acquisition.

Signed-off-by: Srinivas Neeli <srinivas.neeli@xxxxxxx>
---
 drivers/net/ethernet/xilinx/Kconfig           |   1 +
 drivers/net/ethernet/xilinx/Makefile          |   1 +
 drivers/net/ethernet/xilinx/tsn/Kconfig       |  14 ++
 drivers/net/ethernet/xilinx/tsn/Makefile      |   2 +
 drivers/net/ethernet/xilinx/tsn/xilinx_tsn.h  |  60 +++++
 .../net/ethernet/xilinx/tsn/xilinx_tsn_main.c | 218 ++++++++++++++++++
 6 files changed, 296 insertions(+)
 create mode 100644 drivers/net/ethernet/xilinx/tsn/Kconfig
 create mode 100644 drivers/net/ethernet/xilinx/tsn/Makefile
 create mode 100644 drivers/net/ethernet/xilinx/tsn/xilinx_tsn.h
 create mode 100644 drivers/net/ethernet/xilinx/tsn/xilinx_tsn_main.c

diff --git a/drivers/net/ethernet/xilinx/Kconfig b/drivers/net/ethernet/xilinx/Kconfig
index 7502214cc7d5..c6d704c8d3d4 100644
--- a/drivers/net/ethernet/xilinx/Kconfig
+++ b/drivers/net/ethernet/xilinx/Kconfig
@@ -41,4 +41,5 @@ config XILINX_LL_TEMAC
 	  This driver supports the Xilinx 10/100/1000 LocalLink TEMAC
 	  core used in Xilinx Spartan and Virtex FPGAs
 
+source "drivers/net/ethernet/xilinx/tsn/Kconfig"
 endif # NET_VENDOR_XILINX
diff --git a/drivers/net/ethernet/xilinx/Makefile b/drivers/net/ethernet/xilinx/Makefile
index 7d7dc1771423..66dab012650b 100644
--- a/drivers/net/ethernet/xilinx/Makefile
+++ b/drivers/net/ethernet/xilinx/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_XILINX_LL_TEMAC) += ll_temac.o
 obj-$(CONFIG_XILINX_EMACLITE) += xilinx_emaclite.o
 xilinx_emac-objs := xilinx_axienet_main.o xilinx_axienet_mdio.o
 obj-$(CONFIG_XILINX_AXI_EMAC) += xilinx_emac.o
+obj-$(CONFIG_XILINX_TSN) += tsn/
diff --git a/drivers/net/ethernet/xilinx/tsn/Kconfig b/drivers/net/ethernet/xilinx/tsn/Kconfig
new file mode 100644
index 000000000000..53734842700b
--- /dev/null
+++ b/drivers/net/ethernet/xilinx/tsn/Kconfig
@@ -0,0 +1,14 @@
+config XILINX_TSN
+	tristate "Xilinx TSN Ethernet driver"
+	depends on OF && HAS_IOMEM
+	select PHYLIB
+	select NET_DEVLINK
+	select NET_DEV_STATS
+	help
+	  This driver supports the Xilinx Time-Sensitive Networking (TSN)
+	  Ethernet IP, which includes multiple Ethernet MACs, a TSN switch,
+	  and an endpoint block. It provides support for scheduling,
+	  traffic shaping, and time synchronization to meet real-time
+	  requirements of industrial Ethernet applications.
+
+	  If unsure, say N.
diff --git a/drivers/net/ethernet/xilinx/tsn/Makefile b/drivers/net/ethernet/xilinx/tsn/Makefile
new file mode 100644
index 000000000000..420497f2d402
--- /dev/null
+++ b/drivers/net/ethernet/xilinx/tsn/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_XILINX_TSN) :=xilinx_tsn.o
+xilinx_tsn-objs := xilinx_tsn_main.o
diff --git a/drivers/net/ethernet/xilinx/tsn/xilinx_tsn.h b/drivers/net/ethernet/xilinx/tsn/xilinx_tsn.h
new file mode 100644
index 000000000000..fe613f73044f
--- /dev/null
+++ b/drivers/net/ethernet/xilinx/tsn/xilinx_tsn.h
@@ -0,0 +1,60 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Time Sensitive Networking (TSN) Ethernet MAC driver
+ *
+ * Copyright (C) 2025 Advanced Micro Devices, Inc.
+ */
+
+#ifndef XILINX_TSN_H
+#define XILINX_TSN_H
+
+#include <linux/clk.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+#define TSN_NUM_CLOCKS		6
+
+#define TSN_DMA_CH_INVALID	GENMASK(7, 0)
+#define TSN_DMA_MAX_TX_CH	GENMASK(3, 0)
+#define TSN_MAX_TX_QUEUE	8
+#define TSN_MIN_PRIORITIES	2
+#define TSN_MAX_PRIORITIES	8
+/**
+ * struct tsn_priv - Main TSN private data structure
+ * @pdev: Platform device handle
+ * @dev: Device pointer for this TSN instance
+ * @res: Platform resource information
+ * @regs_start: Start address (physical) of mapped region
+ * @regs: ioremap()'d base pointer
+ * @clks: Bulk clock data for all required clocks
+ * @tx_lock: Spinlock protecting TX rings and related TX state
+ * @rx_lock: Spinlock protecting RX rings and related RX state
+ * @mdio_lock: Mutex placeholder for future MDIO serialization
+ * @num_priorities: Number of priority queues configured
+ * @num_tx_queues: Number of TX DMA queues
+ * @num_rx_queues: Number of RX DMA queues
+ * @tx_dma_chan_map: Logical TX queue index to DMA channel number mapping.
+ */
+struct tsn_priv {
+	struct platform_device *pdev;
+	struct device *dev;
+	struct resource *res;
+	resource_size_t regs_start;
+	void __iomem *regs;
+	struct clk_bulk_data clks[TSN_NUM_CLOCKS];
+	spinlock_t tx_lock;	/* Protects TX ring buffers */
+	spinlock_t rx_lock;	/* Protects RX ring buffers */
+	struct mutex mdio_lock; /* Serializes MDIO access across all EMACs */
+	u32 num_priorities;
+	u32 num_tx_queues;
+	u32 num_rx_queues;
+	u32 tx_dma_chan_map[TSN_MAX_TX_QUEUE];
+};
+
+#endif /* XILINX_TSN_H */
diff --git a/drivers/net/ethernet/xilinx/tsn/xilinx_tsn_main.c b/drivers/net/ethernet/xilinx/tsn/xilinx_tsn_main.c
new file mode 100644
index 000000000000..2a7f5fbc5510
--- /dev/null
+++ b/drivers/net/ethernet/xilinx/tsn/xilinx_tsn_main.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Time Sensitive Networking (TSN) Ethernet MAC driver
+ *
+ * Copyright (C) 2025 Advanced Micro Devices, Inc.
+ */
+
+#include "xilinx_tsn.h"
+
+static const char * const tsn_clk_names[TSN_NUM_CLOCKS] = {
+	"gtx",
+	"gtx90",
+	"host_rxfifo",
+	"host_txfifo",
+	"ref",
+	"s_axi",
+};
+
+/*
+ * Helper to parse TX queue config subnode referenced by
+ * xlnx,tsn-tx-config. This version enumerates child nodes in order and
+ * assigns DMA channels sequentially (queue0 == first child, etc.)
+ */
+static int tsn_parse_tx_queue_config(struct device *dev, struct tsn_priv *common,
+				     struct device_node *txcfg_np)
+{
+	struct device_node *qnode;
+	unsigned int queue = 0;
+	int ret = 0;
+
+	for_each_available_child_of_node(txcfg_np, qnode) {
+		u32 chan;
+
+		if (queue >= common->num_tx_queues) {
+			dev_err(dev, "tx-config: extra child nodes beyond %u ignored\n",
+				common->num_tx_queues);
+			of_node_put(qnode);
+			return -EINVAL;
+		}
+
+		ret = of_property_read_u32(qnode, "xlnx,dma-channel-num", &chan);
+		if (ret) {
+			dev_err(dev, "tx-config: Q%u missing xlnx,dma-channel-num\n", queue);
+			of_node_put(qnode);
+			return ret;
+		}
+
+		if (chan > TSN_DMA_MAX_TX_CH) {
+			dev_err(dev, "tx-config: Q%u channel %u exceeds max %lu\n",
+				queue, chan, TSN_DMA_MAX_TX_CH);
+			of_node_put(qnode);
+			return -EINVAL;
+		}
+		common->tx_dma_chan_map[queue++] = chan;
+	}
+
+	if (queue != common->num_tx_queues) {
+		dev_err(dev, "tx-config: described %u queues but expected %u\n",
+			queue, common->num_tx_queues);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * tsn_parse_device_tree - Parse device tree configuration for TSN device
+ * @pdev: Platform device pointer
+ *
+ * Return: 0 on success, negative error code on failure
+ */
+static int tsn_parse_device_tree(struct platform_device *pdev)
+{
+	struct tsn_priv *common = platform_get_drvdata(pdev);
+	struct device_node *txcfg_np = NULL;
+	struct device *dev = &pdev->dev;
+	int i, ret;
+
+	/* Read number of priorities */
+	ret = of_property_read_u32(dev->of_node, "xlnx,num-priorities", &common->num_priorities);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get xlnx,num-priorities\n");
+
+	if (common->num_priorities < TSN_MIN_PRIORITIES ||
+	    common->num_priorities > TSN_MAX_PRIORITIES)
+		return dev_err_probe(dev, -EINVAL, "Invalid xlnx,num-priorities (%u)\n",
+				     common->num_priorities);
+
+	/* Count TX and RX queues from dma-names property */
+	ret = of_property_count_strings(dev->of_node, "dma-names");
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Failed to get dma-names\n");
+
+	common->num_tx_queues = 0;
+	common->num_rx_queues = 0;
+
+	for (i = 0; i < ret; i++) {
+		const char *dma_name;
+
+		if (of_property_read_string_index(dev->of_node, "dma-names", i, &dma_name))
+			continue;
+
+		if (strncmp(dma_name, "tx_chan", 7) == 0)
+			common->num_tx_queues++;
+		else if (strncmp(dma_name, "rx_chan", 7) == 0)
+			common->num_rx_queues++;
+	}
+
+	if (!common->num_tx_queues || common->num_tx_queues > TSN_MAX_TX_QUEUE)
+		return dev_err_probe(dev, -EINVAL,
+				     "Invalid TX queue count (%u, max %u)\n",
+				     common->num_tx_queues, TSN_MAX_TX_QUEUE);
+
+	if (!common->num_rx_queues)
+		return dev_err_probe(dev, -EINVAL, "No RX DMA channels found\n");
+
+	/* Setup clock IDs */
+	for (i = 0; i < TSN_NUM_CLOCKS; i++)
+		common->clks[i].id = tsn_clk_names[i];
+
+	/* Get all clocks */
+	ret = devm_clk_bulk_get(dev, TSN_NUM_CLOCKS, common->clks);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get clocks\n");
+
+	/* Enable clocks */
+	ret = clk_bulk_prepare_enable(TSN_NUM_CLOCKS, common->clks);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to enable clocks\n");
+
+	for (i = 0; i < TSN_MAX_TX_QUEUE; i++)
+		common->tx_dma_chan_map[i] = TSN_DMA_CH_INVALID;
+
+	txcfg_np = of_parse_phandle(dev->of_node, "xlnx,tsn-tx-config", 0);
+	if (txcfg_np) {
+		ret = tsn_parse_tx_queue_config(dev, common, txcfg_np);
+		of_node_put(txcfg_np);
+		if (ret)
+			goto err_disable_clks;
+	}
+
+	return 0;
+
+err_disable_clks:
+	clk_bulk_disable_unprepare(TSN_NUM_CLOCKS, common->clks);
+	return ret;
+}
+
+/**
+ * tsn_ip_probe - Probe TSN IP core device
+ * @pdev: Platform device pointer
+ *
+ * Return: 0 on success, negative error code on failure
+ */
+static int tsn_ip_probe(struct platform_device *pdev)
+{
+	struct tsn_priv *common;
+	int ret;
+
+	common = devm_kzalloc(&pdev->dev, sizeof(*common), GFP_KERNEL);
+	if (!common)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, common);
+	common->pdev = pdev;
+	common->dev = &pdev->dev;
+
+	/* Initialize synchronization primitives */
+	spin_lock_init(&common->tx_lock);
+	spin_lock_init(&common->rx_lock);
+	mutex_init(&common->mdio_lock);
+
+	common->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!common->res)
+		return -ENODEV;
+	common->regs_start = common->res->start;
+	common->regs = devm_ioremap_resource(&pdev->dev, common->res);
+	if (IS_ERR(common->regs))
+		return PTR_ERR(common->regs);
+
+	ret = tsn_parse_device_tree(pdev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+/**
+ * tsn_ip_remove - Remove TSN IP core device
+ * @pdev: Platform device pointer
+ */
+static void tsn_ip_remove(struct platform_device *pdev)
+{
+	struct tsn_priv *common = platform_get_drvdata(pdev);
+
+	clk_bulk_disable_unprepare(TSN_NUM_CLOCKS, common->clks);
+}
+
+static const struct of_device_id tsn_of_match[] = {
+	{ .compatible = "xlnx,tsn-endpoint-ethernet-mac-3.0", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, tsn_of_match);
+
+static struct platform_driver tsn_driver = {
+	.probe = tsn_ip_probe,
+	.remove = tsn_ip_remove,
+	.driver = {
+		.name = "xilinx-tsn",
+		.of_match_table = tsn_of_match,
+	},
+};
+module_platform_driver(tsn_driver);
+
+MODULE_AUTHOR("Neeli Srinivas <srinivas.neeli@xxxxxxx>");
+MODULE_DESCRIPTION("Time Sensitive Networking (TSN) Ethernet MAC driver");
+MODULE_LICENSE("GPL");
-- 
2.25.1