openwrt-mirror/target/linux/microchipsw/patches-6.12/0075-v6.14-net-lan969x-add-FDMA-implementation.patch

From 181ee0484e3a966b02ddb238c2abfdbecebafe97 Mon Sep 17 00:00:00 2001
From: Daniel Machon <daniel.machon@microchip.com>
Date: Mon, 13 Jan 2025 20:36:09 +0100
Subject: [PATCH 80/82] net: lan969x: add FDMA implementation

The lan969x switch device supports manual frame injection and extraction
to and from the switch core, using a number of injection and extraction
queues.  This technique is currently supported, but delivers poor
performance compared to Frame DMA (FDMA).

This lan969x implementation of FDMA, hooks into the existing FDMA for
Sparx5, but requires its own RX and TX handling, as lan969x does not
support the same native cache coherency that Sparx5 does. Effectively,
this means that we are going to use the DMA mapping API for mapping and
unmapping TX buffers. The RX loop will utilize the page pool API for
efficient RX handling. Other than that, the implementation is largely
the same, and utilizes the FDMA library for DCB and DB handling.

Some numbers:

Manual injection/extraction (before this series):

// iperf3 -c 1.0.1.1

[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.02  sec   345 MBytes   289 Mbits/sec  sender
[  5]   0.00-10.06  sec   345 MBytes   288 Mbits/sec  receiver

FDMA (after this series):

// iperf3 -c 1.0.1.1

[ ID] Interval           Transfer     Bitrate
[  5]   0.00-10.03  sec  1.10 GBytes   940 Mbits/sec  sender
[  5]   0.00-10.07  sec  1.10 GBytes   936 Mbits/sec  receiver

Reviewed-by: Steen Hegelund <Steen.Hegelund@microchip.com>
Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
Link: https://patch.msgid.link/20250113-sparx5-lan969x-switch-driver-5-v2-5-c468f02fd623@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/microchip/sparx5/Kconfig |   1 +
 .../net/ethernet/microchip/sparx5/Makefile    |   3 +-
 .../microchip/sparx5/lan969x/lan969x.c        |   4 +
 .../microchip/sparx5/lan969x/lan969x.h        |   7 +
 .../microchip/sparx5/lan969x/lan969x_fdma.c   | 406 ++++++++++++++++++
 .../ethernet/microchip/sparx5/sparx5_fdma.c   |   7 +-
 .../ethernet/microchip/sparx5/sparx5_main.h   |  21 +-
 .../ethernet/microchip/sparx5/sparx5_packet.c |   6 +
 8 files changed, 448 insertions(+), 7 deletions(-)
 create mode 100644 drivers/net/ethernet/microchip/sparx5/lan969x/lan969x_fdma.c

--- a/drivers/net/ethernet/microchip/sparx5/Kconfig
+++ b/drivers/net/ethernet/microchip/sparx5/Kconfig
@@ -28,5 +28,6 @@ config SPARX5_DCB
 config LAN969X_SWITCH
 	bool "Lan969x switch driver"
 	depends on SPARX5_SWITCH
+	select PAGE_POOL
 	help
 	  This driver supports the lan969x family of network switch devices.
--- a/drivers/net/ethernet/microchip/sparx5/Makefile
+++ b/drivers/net/ethernet/microchip/sparx5/Makefile
@@ -21,7 +21,8 @@ sparx5-switch-$(CONFIG_LAN969X_SWITCH) +
 					  lan969x/lan969x_calendar.o \
 					  lan969x/lan969x_vcap_ag_api.o \
 					  lan969x/lan969x_vcap_impl.o \
-					  lan969x/lan969x_rgmii.o
+					  lan969x/lan969x_rgmii.o \
+					  lan969x/lan969x_fdma.o
 
 # Provide include files
 ccflags-y += -I$(srctree)/drivers/net/ethernet/microchip/vcap
--- a/drivers/net/ethernet/microchip/sparx5/lan969x/lan969x.c
+++ b/drivers/net/ethernet/microchip/sparx5/lan969x/lan969x.c
@@ -341,6 +341,10 @@ static const struct sparx5_ops lan969x_o
 	.ptp_irq_handler         = &lan969x_ptp_irq_handler,
 	.dsm_calendar_calc       = &lan969x_dsm_calendar_calc,
 	.port_config_rgmii       = &lan969x_port_config_rgmii,
+	.fdma_init               = &lan969x_fdma_init,
+	.fdma_deinit             = &lan969x_fdma_deinit,
+	.fdma_poll               = &lan969x_fdma_napi_poll,
+	.fdma_xmit               = &lan969x_fdma_xmit,
 };
 
 const struct sparx5_match_data lan969x_desc = {
--- a/drivers/net/ethernet/microchip/sparx5/lan969x/lan969x.h
+++ b/drivers/net/ethernet/microchip/sparx5/lan969x/lan969x.h
@@ -72,4 +72,11 @@ int lan969x_dsm_calendar_calc(struct spa
 int lan969x_port_config_rgmii(struct sparx5_port *port,
 			      struct sparx5_port_config *conf);
 
+/* lan969x_fdma.c */
+int lan969x_fdma_init(struct sparx5 *sparx5);
+int lan969x_fdma_deinit(struct sparx5 *sparx5);
+int lan969x_fdma_napi_poll(struct napi_struct *napi, int weight);
+int lan969x_fdma_xmit(struct sparx5 *sparx5, u32 *ifh, struct sk_buff *skb,
+		      struct net_device *dev);
+
 #endif
--- /dev/null
+++ b/drivers/net/ethernet/microchip/sparx5/lan969x/lan969x_fdma.c
@@ -0,0 +1,406 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Microchip lan969x Switch driver
+ *
+ * Copyright (c) 2025 Microchip Technology Inc. and its subsidiaries.
+ */
+#include <net/page_pool/helpers.h>
+
+#include "../sparx5_main.h"
+#include "../sparx5_main_regs.h"
+#include "../sparx5_port.h"
+
+#include "fdma_api.h"
+#include "lan969x.h"
+
+#define FDMA_PRIV(fdma) ((struct sparx5 *)((fdma)->priv))
+
+static int lan969x_fdma_tx_dataptr_cb(struct fdma *fdma, int dcb, int db,
+				      u64 *dataptr)
+{
+	*dataptr = FDMA_PRIV(fdma)->tx.dbs[dcb].dma_addr;
+
+	return 0;
+}
+
+static int lan969x_fdma_rx_dataptr_cb(struct fdma *fdma, int dcb, int db,
+				      u64 *dataptr)
+{
+	struct sparx5_rx *rx = &FDMA_PRIV(fdma)->rx;
+	struct page *page;
+
+	page = page_pool_dev_alloc_pages(rx->page_pool);
+	if (unlikely(!page))
+		return -ENOMEM;
+
+	rx->page[dcb][db] = page;
+
+	*dataptr = page_pool_get_dma_addr(page);
+
+	return 0;
+}
+
+static int lan969x_fdma_get_next_dcb(struct sparx5_tx *tx)
+{
+	struct fdma *fdma = &tx->fdma;
+
+	for (int i = 0; i < fdma->n_dcbs; ++i)
+		if (!tx->dbs[i].used && !fdma_is_last(fdma, &fdma->dcbs[i]))
+			return i;
+
+	return -ENOSPC;
+}
+
+static void lan969x_fdma_tx_clear_buf(struct sparx5 *sparx5, int weight)
+{
+	struct fdma *fdma = &sparx5->tx.fdma;
+	struct sparx5_tx_buf *db;
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&sparx5->tx_lock, flags);
+
+	for (i = 0; i < fdma->n_dcbs; ++i) {
+		db = &sparx5->tx.dbs[i];
+
+		if (!db->used)
+			continue;
+
+		if (!fdma_db_is_done(fdma_db_get(fdma, i, 0)))
+			continue;
+
+		db->dev->stats.tx_bytes += db->skb->len;
+		db->dev->stats.tx_packets++;
+		sparx5->tx.packets++;
+
+		dma_unmap_single(sparx5->dev,
+				 db->dma_addr,
+				 db->skb->len,
+				 DMA_TO_DEVICE);
+
+		if (!db->ptp)
+			napi_consume_skb(db->skb, weight);
+
+		db->used = false;
+	}
+
+	spin_unlock_irqrestore(&sparx5->tx_lock, flags);
+}
+
+static void lan969x_fdma_free_pages(struct sparx5_rx *rx)
+{
+	struct fdma *fdma = &rx->fdma;
+
+	for (int i = 0; i < fdma->n_dcbs; ++i) {
+		for (int j = 0; j < fdma->n_dbs; ++j)
+			page_pool_put_full_page(rx->page_pool,
+						rx->page[i][j], false);
+	}
+}
+
+static struct sk_buff *lan969x_fdma_rx_get_frame(struct sparx5 *sparx5,
+						 struct sparx5_rx *rx)
+{
+	const struct sparx5_consts *consts = sparx5->data->consts;
+	struct fdma *fdma = &rx->fdma;
+	struct sparx5_port *port;
+	struct frame_info fi;
+	struct sk_buff *skb;
+	struct fdma_db *db;
+	struct page *page;
+
+	db = &fdma->dcbs[fdma->dcb_index].db[fdma->db_index];
+	page = rx->page[fdma->dcb_index][fdma->db_index];
+
+	sparx5_ifh_parse(sparx5, page_address(page), &fi);
+	port = fi.src_port < consts->n_ports ? sparx5->ports[fi.src_port] :
+					       NULL;
+	if (WARN_ON(!port))
+		goto free_page;
+
+	skb = build_skb(page_address(page), fdma->db_size);
+	if (unlikely(!skb))
+		goto free_page;
+
+	skb_mark_for_recycle(skb);
+	skb_put(skb, fdma_db_len_get(db));
+	skb_pull(skb, IFH_LEN * sizeof(u32));
+
+	skb->dev = port->ndev;
+
+	if (likely(!(skb->dev->features & NETIF_F_RXFCS)))
+		skb_trim(skb, skb->len - ETH_FCS_LEN);
+
+	sparx5_ptp_rxtstamp(sparx5, skb, fi.timestamp);
+	skb->protocol = eth_type_trans(skb, skb->dev);
+
+	if (test_bit(port->portno, sparx5->bridge_mask))
+		skb->offload_fwd_mark = 1;
+
+	skb->dev->stats.rx_bytes += skb->len;
+	skb->dev->stats.rx_packets++;
+
+	return skb;
+
+free_page:
+	page_pool_recycle_direct(rx->page_pool, page);
+
+	return NULL;
+}
+
+static int lan969x_fdma_rx_alloc(struct sparx5 *sparx5)
+{
+	struct sparx5_rx *rx = &sparx5->rx;
+	struct fdma *fdma = &rx->fdma;
+	int err;
+
+	struct page_pool_params pp_params = {
+		.order = 0,
+		.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV,
+		.pool_size = fdma->n_dcbs * fdma->n_dbs,
+		.nid = NUMA_NO_NODE,
+		.dev = sparx5->dev,
+		.dma_dir = DMA_FROM_DEVICE,
+		.offset = 0,
+		.max_len = fdma->db_size -
+			   SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
+	};
+
+	rx->page_pool = page_pool_create(&pp_params);
+	if (IS_ERR(rx->page_pool))
+		return PTR_ERR(rx->page_pool);
+
+	err = fdma_alloc_coherent(sparx5->dev, fdma);
+	if (err)
+		return err;
+
+	fdma_dcbs_init(fdma,
+		       FDMA_DCB_INFO_DATAL(fdma->db_size),
+		       FDMA_DCB_STATUS_INTR);
+
+	return 0;
+}
+
+static int lan969x_fdma_tx_alloc(struct sparx5 *sparx5)
+{
+	struct sparx5_tx *tx = &sparx5->tx;
+	struct fdma *fdma = &tx->fdma;
+	int err;
+
+	tx->dbs = kcalloc(fdma->n_dcbs,
+			  sizeof(struct sparx5_tx_buf),
+			  GFP_KERNEL);
+	if (!tx->dbs)
+		return -ENOMEM;
+
+	err = fdma_alloc_coherent(sparx5->dev, fdma);
+	if (err) {
+		kfree(tx->dbs);
+		return err;
+	}
+
+	fdma_dcbs_init(fdma,
+		       FDMA_DCB_INFO_DATAL(fdma->db_size),
+		       FDMA_DCB_STATUS_DONE);
+
+	return 0;
+}
+
+static void lan969x_fdma_rx_init(struct sparx5 *sparx5)
+{
+	struct fdma *fdma = &sparx5->rx.fdma;
+
+	fdma->channel_id = FDMA_XTR_CHANNEL;
+	fdma->n_dcbs = FDMA_DCB_MAX;
+	fdma->n_dbs = 1;
+	fdma->priv = sparx5;
+	fdma->size = fdma_get_size(fdma);
+	fdma->db_size = PAGE_SIZE;
+	fdma->ops.dataptr_cb = &lan969x_fdma_rx_dataptr_cb;
+	fdma->ops.nextptr_cb = &fdma_nextptr_cb;
+
+	/* Fetch a netdev for SKB and NAPI use, any will do */
+	for (int idx = 0; idx < sparx5->data->consts->n_ports; ++idx) {
+		struct sparx5_port *port = sparx5->ports[idx];
+
+		if (port && port->ndev) {
+			sparx5->rx.ndev = port->ndev;
+			break;
+		}
+	}
+}
+
+static void lan969x_fdma_tx_init(struct sparx5 *sparx5)
+{
+	struct fdma *fdma = &sparx5->tx.fdma;
+
+	fdma->channel_id = FDMA_INJ_CHANNEL;
+	fdma->n_dcbs = FDMA_DCB_MAX;
+	fdma->n_dbs = 1;
+	fdma->priv = sparx5;
+	fdma->size = fdma_get_size(fdma);
+	fdma->db_size = PAGE_SIZE;
+	fdma->ops.dataptr_cb = &lan969x_fdma_tx_dataptr_cb;
+	fdma->ops.nextptr_cb = &fdma_nextptr_cb;
+}
+
+int lan969x_fdma_napi_poll(struct napi_struct *napi, int weight)
+{
+	struct sparx5_rx *rx = container_of(napi, struct sparx5_rx, napi);
+	struct sparx5 *sparx5 = container_of(rx, struct sparx5, rx);
+	int old_dcb, dcb_reload, counter = 0;
+	struct fdma *fdma = &rx->fdma;
+	struct sk_buff *skb;
+
+	dcb_reload = fdma->dcb_index;
+
+	lan969x_fdma_tx_clear_buf(sparx5, weight);
+
+	/* Process RX data */
+	while (counter < weight) {
+		if (!fdma_has_frames(fdma))
+			break;
+
+		skb = lan969x_fdma_rx_get_frame(sparx5, rx);
+		if (!skb)
+			break;
+
+		napi_gro_receive(&rx->napi, skb);
+
+		fdma_db_advance(fdma);
+		counter++;
+		/* Check if the DCB can be reused */
+		if (fdma_dcb_is_reusable(fdma))
+			continue;
+
+		fdma_db_reset(fdma);
+		fdma_dcb_advance(fdma);
+	}
+
+	/* Allocate new pages and map them */
+	while (dcb_reload != fdma->dcb_index) {
+		old_dcb = dcb_reload;
+		dcb_reload++;
+		 /* n_dcbs must be a power of 2 */
+		dcb_reload &= fdma->n_dcbs - 1;
+
+		fdma_dcb_add(fdma,
+			     old_dcb,
+			     FDMA_DCB_INFO_DATAL(fdma->db_size),
+			     FDMA_DCB_STATUS_INTR);
+
+		sparx5_fdma_reload(sparx5, fdma);
+	}
+
+	if (counter < weight && napi_complete_done(napi, counter))
+		spx5_wr(0xff, sparx5, FDMA_INTR_DB_ENA);
+
+	return counter;
+}
+
+int lan969x_fdma_xmit(struct sparx5 *sparx5, u32 *ifh, struct sk_buff *skb,
+		      struct net_device *dev)
+{
+	int next_dcb, needed_headroom, needed_tailroom, err;
+	struct sparx5_tx *tx = &sparx5->tx;
+	struct fdma *fdma = &tx->fdma;
+	struct sparx5_tx_buf *db_buf;
+	u64 status;
+
+	next_dcb = lan969x_fdma_get_next_dcb(tx);
+	if (next_dcb < 0)
+		return -EBUSY;
+
+	needed_headroom = max_t(int, IFH_LEN * 4 - skb_headroom(skb), 0);
+	needed_tailroom = max_t(int, ETH_FCS_LEN - skb_tailroom(skb), 0);
+	if (needed_headroom || needed_tailroom || skb_header_cloned(skb)) {
+		err = pskb_expand_head(skb, needed_headroom, needed_tailroom,
+				       GFP_ATOMIC);
+		if (unlikely(err))
+			return err;
+	}
+
+	skb_push(skb, IFH_LEN * 4);
+	memcpy(skb->data, ifh, IFH_LEN * 4);
+	skb_put(skb, ETH_FCS_LEN);
+
+	db_buf = &tx->dbs[next_dcb];
+	db_buf->dma_addr = dma_map_single(sparx5->dev,
+					  skb->data,
+					  skb->len,
+					  DMA_TO_DEVICE);
+	if (dma_mapping_error(sparx5->dev, db_buf->dma_addr))
+		return -ENOMEM;
+
+	db_buf->dev = dev;
+	db_buf->skb = skb;
+	db_buf->ptp = false;
+	db_buf->used = true;
+
+	if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP &&
+	    SPARX5_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP)
+		db_buf->ptp = true;
+
+	status = FDMA_DCB_STATUS_SOF |
+		 FDMA_DCB_STATUS_EOF |
+		 FDMA_DCB_STATUS_BLOCKO(0) |
+		 FDMA_DCB_STATUS_BLOCKL(skb->len) |
+		 FDMA_DCB_STATUS_INTR;
+
+	fdma_dcb_advance(fdma);
+	fdma_dcb_add(fdma, next_dcb, 0, status);
+
+	sparx5_fdma_reload(sparx5, fdma);
+
+	return NETDEV_TX_OK;
+}
+
+int lan969x_fdma_init(struct sparx5 *sparx5)
+{
+	struct sparx5_rx *rx = &sparx5->rx;
+	int err;
+
+	lan969x_fdma_rx_init(sparx5);
+	lan969x_fdma_tx_init(sparx5);
+	sparx5_fdma_injection_mode(sparx5);
+
+	err = dma_set_mask_and_coherent(sparx5->dev, DMA_BIT_MASK(64));
+	if (err) {
+		dev_err(sparx5->dev, "Failed to set 64-bit FDMA mask");
+		return err;
+	}
+
+	err = lan969x_fdma_rx_alloc(sparx5);
+	if (err) {
+		dev_err(sparx5->dev, "Failed to allocate RX buffers: %d\n",
+			err);
+		return err;
+	}
+
+	err = lan969x_fdma_tx_alloc(sparx5);
+	if (err) {
+		fdma_free_coherent(sparx5->dev, &rx->fdma);
+		dev_err(sparx5->dev, "Failed to allocate TX buffers: %d\n",
+			err);
+		return err;
+	}
+
+	/* Reset FDMA state */
+	spx5_wr(FDMA_CTRL_NRESET_SET(0), sparx5, FDMA_CTRL);
+	spx5_wr(FDMA_CTRL_NRESET_SET(1), sparx5, FDMA_CTRL);
+
+	return err;
+}
+
+int lan969x_fdma_deinit(struct sparx5 *sparx5)
+{
+	struct sparx5_rx *rx = &sparx5->rx;
+	struct sparx5_tx *tx = &sparx5->tx;
+
+	sparx5_fdma_stop(sparx5);
+	fdma_free_coherent(sparx5->dev, &tx->fdma);
+	fdma_free_coherent(sparx5->dev, &rx->fdma);
+	lan969x_fdma_free_pages(rx);
+	page_pool_destroy(rx->page_pool);
+
+	return 0;
+}
--- a/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c
+++ b/drivers/net/ethernet/microchip/sparx5/sparx5_fdma.c
@@ -18,9 +18,6 @@
 #include "sparx5_main.h"
 #include "sparx5_port.h"
 
-#define FDMA_XTR_CHANNEL		6
-#define FDMA_INJ_CHANNEL		0
-
 #define FDMA_XTR_BUFFER_SIZE		2048
 #define FDMA_WEIGHT			4
 
@@ -133,7 +130,7 @@ static void sparx5_fdma_tx_deactivate(st
 		 sparx5, FDMA_CH_ACTIVATE);
 }
 
-static void sparx5_fdma_reload(struct sparx5 *sparx5, struct fdma *fdma)
+void sparx5_fdma_reload(struct sparx5 *sparx5, struct fdma *fdma)
 {
 	/* Reload the RX channel */
 	spx5_wr(BIT(fdma->channel_id), sparx5, FDMA_CH_RELOAD);
@@ -340,7 +337,7 @@ irqreturn_t sparx5_fdma_handler(int irq,
 	return IRQ_HANDLED;
 }
 
-static void sparx5_fdma_injection_mode(struct sparx5 *sparx5)
+void sparx5_fdma_injection_mode(struct sparx5 *sparx5)
 {
 	const int byte_swap = 1;
 	int portno;
--- a/drivers/net/ethernet/microchip/sparx5/sparx5_main.h
+++ b/drivers/net/ethernet/microchip/sparx5/sparx5_main.h
@@ -112,6 +112,8 @@ enum sparx5_feature {
 #define XTR_QUEUE     0
 #define INJ_QUEUE     0
 
+#define FDMA_XTR_CHANNEL		6
+#define FDMA_INJ_CHANNEL		0
 #define FDMA_DCB_MAX			64
 #define FDMA_RX_DCB_MAX_DBS		15
 #define FDMA_TX_DCB_MAX_DBS		1
@@ -157,11 +159,25 @@ struct sparx5_calendar_data {
  */
 struct sparx5_rx {
 	struct fdma fdma;
-	struct sk_buff *skb[FDMA_DCB_MAX][FDMA_RX_DCB_MAX_DBS];
+	struct page_pool *page_pool;
+	union {
+		struct sk_buff *skb[FDMA_DCB_MAX][FDMA_RX_DCB_MAX_DBS];
+		struct page *page[FDMA_DCB_MAX][FDMA_RX_DCB_MAX_DBS];
+	};
 	dma_addr_t dma;
 	struct napi_struct napi;
 	struct net_device *ndev;
 	u64 packets;
+	u8 page_order;
+};
+
+/* Used to store information about TX buffers. */
+struct sparx5_tx_buf {
+	struct net_device *dev;
+	struct sk_buff *skb;
+	dma_addr_t dma_addr;
+	bool used;
+	bool ptp;
 };
 
 /* Frame DMA transmit state:
@@ -169,6 +185,7 @@ struct sparx5_rx {
  */
 struct sparx5_tx {
 	struct fdma fdma;
+	struct sparx5_tx_buf *dbs;
 	u64 packets;
 	u64 dropped;
 };
@@ -449,6 +466,8 @@ int sparx5_fdma_napi_callback(struct nap
 int sparx5_fdma_xmit(struct sparx5 *sparx5, u32 *ifh, struct sk_buff *skb,
 		     struct net_device *dev);
 irqreturn_t sparx5_fdma_handler(int irq, void *args);
+void sparx5_fdma_reload(struct sparx5 *sparx5, struct fdma *fdma);
+void sparx5_fdma_injection_mode(struct sparx5 *sparx5);
 
 /* sparx5_mactable.c */
 void sparx5_mact_pull_work(struct work_struct *work);
--- a/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c
+++ b/drivers/net/ethernet/microchip/sparx5/sparx5_packet.c
@@ -267,6 +267,12 @@ netdev_tx_t sparx5_port_xmit_impl(struct
 	if (ret < 0)
 		goto drop;
 
+	if (!is_sparx5(sparx5))
+		/* When lan969x and TX_OK, stats and SKB consumption is handled
+		 * in the TX completion loop, so dont go any further.
+		 */
+		return NETDEV_TX_OK;
+
 	stats->tx_bytes += skb->len;
 	stats->tx_packets++;
 	sparx5->tx.packets++;