Merge branch 'net-lan966x-use-the-newly-introduced-fdma-library'

Daniel Machon says:

====================
net: lan966x: use the newly introduced FDMA library

This patch series is the second of a 2-part series [1], that adds a new
common FDMA library for Microchip switch chips Sparx5 and lan966x. These
chips share the same FDMA engine, and as such will benefit from a common
library with a common implementation.  This also has the benefit of
removing a lot of open-coded bookkeeping and duplicate code for the two
drivers.

In this second series, the FDMA library will be taken into use by the
lan966x switch driver.

 ###################
 # Example of use: #
 ###################

- Initialize the rx and tx fdma structs with values for: number of
  DCB's, number of DB's, channel ID, DB size (data buffer size), and
  total size of the requested memory. Also provide two callbacks:
  nextptr_cb() and dataptr_cb() for getting the nextptr and dataptr.

- Allocate memory using fdma_alloc_phys() or fdma_alloc_coherent().

- Initialize the DCB's with fdma_dcb_init().

- Add new DCB's with fdma_dcb_add().

- Free memory with fdma_free_phys() or fdma_free_coherent().

 #####################
 # Patch  breakdown: #
 #####################

Patch #1:  select FDMA library for lan966x.

Patch #2:  includes the fdma_api.h header and removes old symbols.

Patch #3:  replaces old rx and tx variables with equivalent ones from the
           fdma struct. Only the variables that can be changed without
           breaking traffic is changed in this patch.

Patch #4:  uses the library for allocation of rx buffers. This requires
           quite a bit of refactoring in this single patch.

Patch #5:  uses the library for adding DCB's in the rx path.

Patch #6:  uses the library for freeing rx buffers.

Patch #7:  uses the library for allocation of tx buffers. This requires
           quite a bit of refactoring in this single patch.

Patch #8:  uses the library for adding DCB's in the tx path.

Patch #9:  uses the library helpers in the tx path.

Patch #10: ditch last_in_use variable and use library instead.

Patch #11: uses library helpers throughout.

Patch #12: refactor lan966x_fdma_reload() function.

[1] https://lore.kernel.org/netdev/20240902-fdma-sparx5-v1-0-1e7d5e5a9f34@microchip.com/Signed-off-by: Daniel Machon <daniel.machon@microchip.com>
====================

Link: https://patch.msgid.link/20240905-fdma-lan966x-v1-0-e083f8620165@microchip.comSigned-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/microchip/lan966x/Kconfig

@@ -8,6 +8,7 @@ config LAN966X_SWITCH
 	select PHYLINK
 	select PAGE_POOL
 	select VCAP
+	select FDMA
 	help
 	  This driver supports the Lan966x network switch device.
 

drivers/net/ethernet/microchip/lan966x/Makefile

@@ -20,3 +20,4 @@ lan966x-switch-$(CONFIG_DEBUG_FS) += lan966x_vcap_debugfs.o
 
 # Provide include files
 ccflags-y += -I$(srctree)/drivers/net/ethernet/microchip/vcap
+ccflags-y += -I$(srctree)/drivers/net/ethernet/microchip/fdma

drivers/net/ethernet/microchip/lan966x/lan966x_fdma.c

@@ -6,31 +6,55 @@
 
 #include "lan966x_main.h"
 
-static int lan966x_fdma_channel_active(struct lan966x *lan966x)
-{
-	return lan_rd(lan966x, FDMA_CH_ACTIVE);
-}
-
-static struct page *lan966x_fdma_rx_alloc_page(struct lan966x_rx *rx,
-					       struct lan966x_db *db)
+static int lan966x_fdma_rx_dataptr_cb(struct fdma *fdma, int dcb, int db,
+				      u64 *dataptr)
 {
+	struct lan966x *lan966x = (struct lan966x *)fdma->priv;
+	struct lan966x_rx *rx = &lan966x->rx;
 	struct page *page;
 
 	page = page_pool_dev_alloc_pages(rx->page_pool);
 	if (unlikely(!page))
-		return NULL;
+		return -ENOMEM;
+
+	rx->page[dcb][db] = page;
+	*dataptr = page_pool_get_dma_addr(page) + XDP_PACKET_HEADROOM;
+
+	return 0;
+}
 
-	db->dataptr = page_pool_get_dma_addr(page) + XDP_PACKET_HEADROOM;
+static int lan966x_fdma_tx_dataptr_cb(struct fdma *fdma, int dcb, int db,
+				      u64 *dataptr)
+{
+	struct lan966x *lan966x = (struct lan966x *)fdma->priv;
+
+	*dataptr = lan966x->tx.dcbs_buf[dcb].dma_addr;
 
-	return page;
+	return 0;
+}
+
+static int lan966x_fdma_xdp_tx_dataptr_cb(struct fdma *fdma, int dcb, int db,
+					  u64 *dataptr)
+{
+	struct lan966x *lan966x = (struct lan966x *)fdma->priv;
+
+	*dataptr = lan966x->tx.dcbs_buf[dcb].dma_addr + XDP_PACKET_HEADROOM;
+
+	return 0;
+}
+
+static int lan966x_fdma_channel_active(struct lan966x *lan966x)
+{
+	return lan_rd(lan966x, FDMA_CH_ACTIVE);
 }
 
 static void lan966x_fdma_rx_free_pages(struct lan966x_rx *rx)
 {
+	struct fdma *fdma = &rx->fdma;
 	int i, j;
 
-	for (i = 0; i < FDMA_DCB_MAX; ++i) {
-		for (j = 0; j < FDMA_RX_DCB_MAX_DBS; ++j)
+	for (i = 0; i < fdma->n_dcbs; ++i) {
+		for (j = 0; j < fdma->n_dbs; ++j)
 			page_pool_put_full_page(rx->page_pool,
 						rx->page[i][j], false);
 	}
@@ -38,41 +62,23 @@ static void lan966x_fdma_rx_free_pages(struct lan966x_rx *rx)
 
 static void lan966x_fdma_rx_free_page(struct lan966x_rx *rx)
 {
+	struct fdma *fdma = &rx->fdma;
 	struct page *page;
 
-	page = rx->page[rx->dcb_index][rx->db_index];
+	page = rx->page[fdma->dcb_index][fdma->db_index];
 	if (unlikely(!page))
 		return;
 
 	page_pool_recycle_direct(rx->page_pool, page);
 }
 
-static void lan966x_fdma_rx_add_dcb(struct lan966x_rx *rx,
-				    struct lan966x_rx_dcb *dcb,
-				    u64 nextptr)
-{
-	struct lan966x_db *db;
-	int i;
-
-	for (i = 0; i < FDMA_RX_DCB_MAX_DBS; ++i) {
-		db = &dcb->db[i];
-		db->status = FDMA_DCB_STATUS_INTR;
-	}
-
-	dcb->nextptr = FDMA_DCB_INVALID_DATA;
-	dcb->info = FDMA_DCB_INFO_DATAL(PAGE_SIZE << rx->page_order);
-
-	rx->last_entry->nextptr = nextptr;
-	rx->last_entry = dcb;
-}
-
 static int lan966x_fdma_rx_alloc_page_pool(struct lan966x_rx *rx)
 {
 	struct lan966x *lan966x = rx->lan966x;
 	struct page_pool_params pp_params = {
 		.order = rx->page_order,
 		.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV,
-		.pool_size = FDMA_DCB_MAX,
+		.pool_size = rx->fdma.n_dcbs,
 		.nid = NUMA_NO_NODE,
 		.dev = lan966x->dev,
 		.dma_dir = DMA_FROM_DEVICE,
@@ -104,84 +110,41 @@ static int lan966x_fdma_rx_alloc_page_pool(struct lan966x_rx *rx)
 static int lan966x_fdma_rx_alloc(struct lan966x_rx *rx)
 {
 	struct lan966x *lan966x = rx->lan966x;
-	struct lan966x_rx_dcb *dcb;
-	struct lan966x_db *db;
-	struct page *page;
-	int i, j;
-	int size;
+	struct fdma *fdma = &rx->fdma;
+	int err;
 
 	if (lan966x_fdma_rx_alloc_page_pool(rx))
 		return PTR_ERR(rx->page_pool);
 
-	/* calculate how many pages are needed to allocate the dcbs */
-	size = sizeof(struct lan966x_rx_dcb) * FDMA_DCB_MAX;
-	size = ALIGN(size, PAGE_SIZE);
-
-	rx->dcbs = dma_alloc_coherent(lan966x->dev, size, &rx->dma, GFP_KERNEL);
-	if (!rx->dcbs)
-		return -ENOMEM;
-
-	rx->last_entry = rx->dcbs;
-	rx->db_index = 0;
-	rx->dcb_index = 0;
-
-	/* Now for each dcb allocate the dbs */
-	for (i = 0; i < FDMA_DCB_MAX; ++i) {
-		dcb = &rx->dcbs[i];
-		dcb->info = 0;
-
-		/* For each db allocate a page and map it to the DB dataptr. */
-		for (j = 0; j < FDMA_RX_DCB_MAX_DBS; ++j) {
-			db = &dcb->db[j];
-			page = lan966x_fdma_rx_alloc_page(rx, db);
-			if (!page)
-				return -ENOMEM;
-
-			db->status = 0;
-			rx->page[i][j] = page;
-		}
+	err = fdma_alloc_coherent(lan966x->dev, fdma);
+	if (err)
+		return err;
 
-		lan966x_fdma_rx_add_dcb(rx, dcb, rx->dma + sizeof(*dcb) * i);
-	}
+	fdma_dcbs_init(fdma, FDMA_DCB_INFO_DATAL(fdma->db_size),
+		       FDMA_DCB_STATUS_INTR);
 
 	return 0;
 }
 
-static void lan966x_fdma_rx_advance_dcb(struct lan966x_rx *rx)
-{
-	rx->dcb_index++;
-	rx->dcb_index &= FDMA_DCB_MAX - 1;
-}
-
-static void lan966x_fdma_rx_free(struct lan966x_rx *rx)
-{
-	struct lan966x *lan966x = rx->lan966x;
-	u32 size;
-
-	/* Now it is possible to do the cleanup of dcb */
-	size = sizeof(struct lan966x_tx_dcb) * FDMA_DCB_MAX;
-	size = ALIGN(size, PAGE_SIZE);
-	dma_free_coherent(lan966x->dev, size, rx->dcbs, rx->dma);
-}
-
 static void lan966x_fdma_rx_start(struct lan966x_rx *rx)
 {
 	struct lan966x *lan966x = rx->lan966x;
+	struct fdma *fdma = &rx->fdma;
 	u32 mask;
 
 	/* When activating a channel, first is required to write the first DCB
 	 * address and then to activate it
 	 */
-	lan_wr(lower_32_bits((u64)rx->dma), lan966x,
-	       FDMA_DCB_LLP(rx->channel_id));
-	lan_wr(upper_32_bits((u64)rx->dma), lan966x,
-	       FDMA_DCB_LLP1(rx->channel_id));
+	lan_wr(lower_32_bits((u64)fdma->dma), lan966x,
+	       FDMA_DCB_LLP(fdma->channel_id));
+	lan_wr(upper_32_bits((u64)fdma->dma), lan966x,
+	       FDMA_DCB_LLP1(fdma->channel_id));
 
-	lan_wr(FDMA_CH_CFG_CH_DCB_DB_CNT_SET(FDMA_RX_DCB_MAX_DBS) |
+	lan_wr(FDMA_CH_CFG_CH_DCB_DB_CNT_SET(fdma->n_dbs) |
 	       FDMA_CH_CFG_CH_INTR_DB_EOF_ONLY_SET(1) |
 	       FDMA_CH_CFG_CH_INJ_PORT_SET(0) |
 	       FDMA_CH_CFG_CH_MEM_SET(1),
-	       lan966x, FDMA_CH_CFG(rx->channel_id));
+	       lan966x, FDMA_CH_CFG(fdma->channel_id));
 
 	/* Start fdma */
 	lan_rmw(FDMA_PORT_CTRL_XTR_STOP_SET(0),
@@ -191,13 +154,13 @@ static void lan966x_fdma_rx_start(struct lan966x_rx *rx)
 	/* Enable interrupts */
 	mask = lan_rd(lan966x, FDMA_INTR_DB_ENA);
 	mask = FDMA_INTR_DB_ENA_INTR_DB_ENA_GET(mask);
-	mask |= BIT(rx->channel_id);
+	mask |= BIT(fdma->channel_id);
 	lan_rmw(FDMA_INTR_DB_ENA_INTR_DB_ENA_SET(mask),
 		FDMA_INTR_DB_ENA_INTR_DB_ENA,
 		lan966x, FDMA_INTR_DB_ENA);
 
 	/* Activate the channel */
-	lan_rmw(FDMA_CH_ACTIVATE_CH_ACTIVATE_SET(BIT(rx->channel_id)),
+	lan_rmw(FDMA_CH_ACTIVATE_CH_ACTIVATE_SET(BIT(fdma->channel_id)),
 		FDMA_CH_ACTIVATE_CH_ACTIVATE,
 		lan966x, FDMA_CH_ACTIVATE);
 }
@@ -205,18 +168,19 @@ static void lan966x_fdma_rx_start(struct lan966x_rx *rx)
 static void lan966x_fdma_rx_disable(struct lan966x_rx *rx)
 {
 	struct lan966x *lan966x = rx->lan966x;
+	struct fdma *fdma = &rx->fdma;
 	u32 val;
 
 	/* Disable the channel */
-	lan_rmw(FDMA_CH_DISABLE_CH_DISABLE_SET(BIT(rx->channel_id)),
+	lan_rmw(FDMA_CH_DISABLE_CH_DISABLE_SET(BIT(fdma->channel_id)),
 		FDMA_CH_DISABLE_CH_DISABLE,
 		lan966x, FDMA_CH_DISABLE);
 
 	readx_poll_timeout_atomic(lan966x_fdma_channel_active, lan966x,
-				  val, !(val & BIT(rx->channel_id)),
+				  val, !(val & BIT(fdma->channel_id)),
 				  READL_SLEEP_US, READL_TIMEOUT_US);
 
-	lan_rmw(FDMA_CH_DB_DISCARD_DB_DISCARD_SET(BIT(rx->channel_id)),
+	lan_rmw(FDMA_CH_DB_DISCARD_DB_DISCARD_SET(BIT(fdma->channel_id)),
 		FDMA_CH_DB_DISCARD_DB_DISCARD,
 		lan966x, FDMA_CH_DB_DISCARD);
 }
@@ -225,50 +189,27 @@ static void lan966x_fdma_rx_reload(struct lan966x_rx *rx)
 {
 	struct lan966x *lan966x = rx->lan966x;
 
-	lan_rmw(FDMA_CH_RELOAD_CH_RELOAD_SET(BIT(rx->channel_id)),
+	lan_rmw(FDMA_CH_RELOAD_CH_RELOAD_SET(BIT(rx->fdma.channel_id)),
 		FDMA_CH_RELOAD_CH_RELOAD,
 		lan966x, FDMA_CH_RELOAD);
 }
 
-static void lan966x_fdma_tx_add_dcb(struct lan966x_tx *tx,
-				    struct lan966x_tx_dcb *dcb)
-{
-	dcb->nextptr = FDMA_DCB_INVALID_DATA;
-	dcb->info = 0;
-}
-
 static int lan966x_fdma_tx_alloc(struct lan966x_tx *tx)
 {
 	struct lan966x *lan966x = tx->lan966x;
-	struct lan966x_tx_dcb *dcb;
-	struct lan966x_db *db;
-	int size;
-	int i, j;
+	struct fdma *fdma = &tx->fdma;
+	int err;
 
-	tx->dcbs_buf = kcalloc(FDMA_DCB_MAX, sizeof(struct lan966x_tx_dcb_buf),
+	tx->dcbs_buf = kcalloc(fdma->n_dcbs, sizeof(struct lan966x_tx_dcb_buf),
 			       GFP_KERNEL);
 	if (!tx->dcbs_buf)
 		return -ENOMEM;
 
-	/* calculate how many pages are needed to allocate the dcbs */
-	size = sizeof(struct lan966x_tx_dcb) * FDMA_DCB_MAX;
-	size = ALIGN(size, PAGE_SIZE);
-	tx->dcbs = dma_alloc_coherent(lan966x->dev, size, &tx->dma, GFP_KERNEL);
-	if (!tx->dcbs)
+	err = fdma_alloc_coherent(lan966x->dev, fdma);
+	if (err)
 		goto out;
 
-	/* Now for each dcb allocate the db */
-	for (i = 0; i < FDMA_DCB_MAX; ++i) {
-		dcb = &tx->dcbs[i];
-
-		for (j = 0; j < FDMA_TX_DCB_MAX_DBS; ++j) {
-			db = &dcb->db[j];
-			db->dataptr = 0;
-			db->status = 0;
-		}
-
-		lan966x_fdma_tx_add_dcb(tx, dcb);
-	}
+	fdma_dcbs_init(fdma, 0, 0);
 
 	return 0;
 
@@ -280,33 +221,30 @@ static int lan966x_fdma_tx_alloc(struct lan966x_tx *tx)
 static void lan966x_fdma_tx_free(struct lan966x_tx *tx)
 {
 	struct lan966x *lan966x = tx->lan966x;
-	int size;
 
 	kfree(tx->dcbs_buf);
-
-	size = sizeof(struct lan966x_tx_dcb) * FDMA_DCB_MAX;
-	size = ALIGN(size, PAGE_SIZE);
-	dma_free_coherent(lan966x->dev, size, tx->dcbs, tx->dma);
+	fdma_free_coherent(lan966x->dev, &tx->fdma);
 }
 
 static void lan966x_fdma_tx_activate(struct lan966x_tx *tx)
 {
 	struct lan966x *lan966x = tx->lan966x;
+	struct fdma *fdma = &tx->fdma;
 	u32 mask;
 
 	/* When activating a channel, first is required to write the first DCB
 	 * address and then to activate it
 	 */
-	lan_wr(lower_32_bits((u64)tx->dma), lan966x,
-	       FDMA_DCB_LLP(tx->channel_id));
-	lan_wr(upper_32_bits((u64)tx->dma), lan966x,
-	       FDMA_DCB_LLP1(tx->channel_id));
+	lan_wr(lower_32_bits((u64)fdma->dma), lan966x,
+	       FDMA_DCB_LLP(fdma->channel_id));
+	lan_wr(upper_32_bits((u64)fdma->dma), lan966x,
+	       FDMA_DCB_LLP1(fdma->channel_id));
 
-	lan_wr(FDMA_CH_CFG_CH_DCB_DB_CNT_SET(FDMA_TX_DCB_MAX_DBS) |
+	lan_wr(FDMA_CH_CFG_CH_DCB_DB_CNT_SET(fdma->n_dbs) |
 	       FDMA_CH_CFG_CH_INTR_DB_EOF_ONLY_SET(1) |
 	       FDMA_CH_CFG_CH_INJ_PORT_SET(0) |
 	       FDMA_CH_CFG_CH_MEM_SET(1),
-	       lan966x, FDMA_CH_CFG(tx->channel_id));
+	       lan966x, FDMA_CH_CFG(fdma->channel_id));
 
 	/* Start fdma */
 	lan_rmw(FDMA_PORT_CTRL_INJ_STOP_SET(0),
@@ -316,13 +254,13 @@ static void lan966x_fdma_tx_activate(struct lan966x_tx *tx)
 	/* Enable interrupts */
 	mask = lan_rd(lan966x, FDMA_INTR_DB_ENA);
 	mask = FDMA_INTR_DB_ENA_INTR_DB_ENA_GET(mask);
-	mask |= BIT(tx->channel_id);
+	mask |= BIT(fdma->channel_id);
 	lan_rmw(FDMA_INTR_DB_ENA_INTR_DB_ENA_SET(mask),
 		FDMA_INTR_DB_ENA_INTR_DB_ENA,
 		lan966x, FDMA_INTR_DB_ENA);
 
 	/* Activate the channel */
-	lan_rmw(FDMA_CH_ACTIVATE_CH_ACTIVATE_SET(BIT(tx->channel_id)),
+	lan_rmw(FDMA_CH_ACTIVATE_CH_ACTIVATE_SET(BIT(fdma->channel_id)),
 		FDMA_CH_ACTIVATE_CH_ACTIVATE,
 		lan966x, FDMA_CH_ACTIVATE);
 }
@@ -330,23 +268,23 @@ static void lan966x_fdma_tx_activate(struct lan966x_tx *tx)
 static void lan966x_fdma_tx_disable(struct lan966x_tx *tx)
 {
 	struct lan966x *lan966x = tx->lan966x;
+	struct fdma *fdma = &tx->fdma;
 	u32 val;
 
 	/* Disable the channel */
-	lan_rmw(FDMA_CH_DISABLE_CH_DISABLE_SET(BIT(tx->channel_id)),
+	lan_rmw(FDMA_CH_DISABLE_CH_DISABLE_SET(BIT(fdma->channel_id)),
 		FDMA_CH_DISABLE_CH_DISABLE,
 		lan966x, FDMA_CH_DISABLE);
 
 	readx_poll_timeout_atomic(lan966x_fdma_channel_active, lan966x,
-				  val, !(val & BIT(tx->channel_id)),
+				  val, !(val & BIT(fdma->channel_id)),
 				  READL_SLEEP_US, READL_TIMEOUT_US);
 
-	lan_rmw(FDMA_CH_DB_DISCARD_DB_DISCARD_SET(BIT(tx->channel_id)),
+	lan_rmw(FDMA_CH_DB_DISCARD_DB_DISCARD_SET(BIT(fdma->channel_id)),
 		FDMA_CH_DB_DISCARD_DB_DISCARD,
 		lan966x, FDMA_CH_DB_DISCARD);
 
 	tx->activated = false;
-	tx->last_in_use = -1;
 }
 
 static void lan966x_fdma_tx_reload(struct lan966x_tx *tx)
@@ -354,7 +292,7 @@ static void lan966x_fdma_tx_reload(struct lan966x_tx *tx)
 	struct lan966x *lan966x = tx->lan966x;
 
 	/* Write the registers to reload the channel */
-	lan_rmw(FDMA_CH_RELOAD_CH_RELOAD_SET(BIT(tx->channel_id)),
+	lan_rmw(FDMA_CH_RELOAD_CH_RELOAD_SET(BIT(tx->fdma.channel_id)),
 		FDMA_CH_RELOAD_CH_RELOAD,
 		lan966x, FDMA_CH_RELOAD);
 }
@@ -393,23 +331,24 @@ static void lan966x_fdma_tx_clear_buf(struct lan966x *lan966x, int weight)
 	struct lan966x_tx *tx = &lan966x->tx;
 	struct lan966x_rx *rx = &lan966x->rx;
 	struct lan966x_tx_dcb_buf *dcb_buf;
+	struct fdma *fdma = &tx->fdma;
 	struct xdp_frame_bulk bq;
-	struct lan966x_db *db;
 	unsigned long flags;
 	bool clear = false;
+	struct fdma_db *db;
 	int i;
 
 	xdp_frame_bulk_init(&bq);
 
 	spin_lock_irqsave(&lan966x->tx_lock, flags);
-	for (i = 0; i < FDMA_DCB_MAX; ++i) {
+	for (i = 0; i < fdma->n_dcbs; ++i) {
 		dcb_buf = &tx->dcbs_buf[i];
 
 		if (!dcb_buf->used)
 			continue;
 
-		db = &tx->dcbs[i].db[0];
-		if (!(db->status & FDMA_DCB_STATUS_DONE))
+		db = fdma_db_get(fdma, i, 0);
+		if (!fdma_db_is_done(db))
 			continue;
 
 		dcb_buf->dev->stats.tx_packets++;
@@ -449,27 +388,16 @@ static void lan966x_fdma_tx_clear_buf(struct lan966x *lan966x, int weight)
 	spin_unlock_irqrestore(&lan966x->tx_lock, flags);
 }
 
-static bool lan966x_fdma_rx_more_frames(struct lan966x_rx *rx)
-{
-	struct lan966x_db *db;
-
-	/* Check if there is any data */
-	db = &rx->dcbs[rx->dcb_index].db[rx->db_index];
-	if (unlikely(!(db->status & FDMA_DCB_STATUS_DONE)))
-		return false;
-
-	return true;
-}
-
 static int lan966x_fdma_rx_check_frame(struct lan966x_rx *rx, u64 *src_port)
 {
 	struct lan966x *lan966x = rx->lan966x;
+	struct fdma *fdma = &rx->fdma;
 	struct lan966x_port *port;
-	struct lan966x_db *db;
+	struct fdma_db *db;
 	struct page *page;
 
-	db = &rx->dcbs[rx->dcb_index].db[rx->db_index];
-	page = rx->page[rx->dcb_index][rx->db_index];
+	db = fdma_db_next_get(fdma);
+	page = rx->page[fdma->dcb_index][fdma->db_index];
 	if (unlikely(!page))
 		return FDMA_ERROR;
 
@@ -494,16 +422,17 @@ static struct sk_buff *lan966x_fdma_rx_get_frame(struct lan966x_rx *rx,
 						 u64 src_port)
 {
 	struct lan966x *lan966x = rx->lan966x;
-	struct lan966x_db *db;
+	struct fdma *fdma = &rx->fdma;
 	struct sk_buff *skb;
+	struct fdma_db *db;
 	struct page *page;
 	u64 timestamp;
 
 	/* Get the received frame and unmap it */
-	db = &rx->dcbs[rx->dcb_index].db[rx->db_index];
-	page = rx->page[rx->dcb_index][rx->db_index];
+	db = fdma_db_next_get(fdma);
+	page = rx->page[fdma->dcb_index][fdma->db_index];
 
-	skb = build_skb(page_address(page), PAGE_SIZE << rx->page_order);
+	skb = build_skb(page_address(page), fdma->db_size);
 	if (unlikely(!skb))
 		goto free_page;
 
@@ -546,21 +475,19 @@ static int lan966x_fdma_napi_poll(struct napi_struct *napi, int weight)
 {
 	struct lan966x *lan966x = container_of(napi, struct lan966x, napi);
 	struct lan966x_rx *rx = &lan966x->rx;
-	int dcb_reload = rx->dcb_index;
-	struct lan966x_rx_dcb *old_dcb;
-	struct lan966x_db *db;
+	int old_dcb, dcb_reload, counter = 0;
+	struct fdma *fdma = &rx->fdma;
 	bool redirect = false;
 	struct sk_buff *skb;
-	struct page *page;
-	int counter = 0;
 	u64 src_port;
-	u64 nextptr;
+
+	dcb_reload = fdma->dcb_index;
 
 	lan966x_fdma_tx_clear_buf(lan966x, weight);
 
 	/* Get all received skb */
 	while (counter < weight) {
-		if (!lan966x_fdma_rx_more_frames(rx))
+		if (!fdma_has_frames(fdma))
 			break;
 
 		counter++;
@@ -570,22 +497,22 @@ static int lan966x_fdma_napi_poll(struct napi_struct *napi, int weight)
 			break;
 		case FDMA_ERROR:
 			lan966x_fdma_rx_free_page(rx);
-			lan966x_fdma_rx_advance_dcb(rx);
+			fdma_dcb_advance(fdma);
 			goto allocate_new;
 		case FDMA_REDIRECT:
 			redirect = true;
 			fallthrough;
 		case FDMA_TX:
-			lan966x_fdma_rx_advance_dcb(rx);
+			fdma_dcb_advance(fdma);
 			continue;
 		case FDMA_DROP:
 			lan966x_fdma_rx_free_page(rx);
-			lan966x_fdma_rx_advance_dcb(rx);
+			fdma_dcb_advance(fdma);
 			continue;
 		}
 
 		skb = lan966x_fdma_rx_get_frame(rx, src_port);
-		lan966x_fdma_rx_advance_dcb(rx);
+		fdma_dcb_advance(fdma);
 		if (!skb)
 			goto allocate_new;
 
@@ -594,20 +521,14 @@ static int lan966x_fdma_napi_poll(struct napi_struct *napi, int weight)
 
 allocate_new:
 	/* Allocate new pages and map them */
-	while (dcb_reload != rx->dcb_index) {
-		db = &rx->dcbs[dcb_reload].db[rx->db_index];
-		page = lan966x_fdma_rx_alloc_page(rx, db);
-		if (unlikely(!page))
-			break;
-		rx->page[dcb_reload][rx->db_index] = page;
-
-		old_dcb = &rx->dcbs[dcb_reload];
+	while (dcb_reload != fdma->dcb_index) {
+		old_dcb = dcb_reload;
 		dcb_reload++;
-		dcb_reload &= FDMA_DCB_MAX - 1;
+		dcb_reload &= fdma->n_dcbs - 1;
+
+		fdma_dcb_add(fdma, old_dcb, FDMA_DCB_INFO_DATAL(fdma->db_size),
+			     FDMA_DCB_STATUS_INTR);
 
-		nextptr = rx->dma + ((unsigned long)old_dcb -
-				     (unsigned long)rx->dcbs);
-		lan966x_fdma_rx_add_dcb(rx, old_dcb, nextptr);
 		lan966x_fdma_rx_reload(rx);
 	}
 
@@ -650,56 +571,30 @@ irqreturn_t lan966x_fdma_irq_handler(int irq, void *args)
 static int lan966x_fdma_get_next_dcb(struct lan966x_tx *tx)
 {
 	struct lan966x_tx_dcb_buf *dcb_buf;
+	struct fdma *fdma = &tx->fdma;
 	int i;
 
-	for (i = 0; i < FDMA_DCB_MAX; ++i) {
+	for (i = 0; i < fdma->n_dcbs; ++i) {
 		dcb_buf = &tx->dcbs_buf[i];
-		if (!dcb_buf->used && i != tx->last_in_use)
+		if (!dcb_buf->used &&
+		    !fdma_is_last(&tx->fdma, &tx->fdma.dcbs[i]))
 			return i;
 	}
 
 	return -1;
 }
 
-static void lan966x_fdma_tx_setup_dcb(struct lan966x_tx *tx,
-				      int next_to_use, int len,
-				      dma_addr_t dma_addr)
-{
-	struct lan966x_tx_dcb *next_dcb;
-	struct lan966x_db *next_db;
-
-	next_dcb = &tx->dcbs[next_to_use];
-	next_dcb->nextptr = FDMA_DCB_INVALID_DATA;
-
-	next_db = &next_dcb->db[0];
-	next_db->dataptr = dma_addr;
-	next_db->status = FDMA_DCB_STATUS_SOF |
-			  FDMA_DCB_STATUS_EOF |
-			  FDMA_DCB_STATUS_INTR |
-			  FDMA_DCB_STATUS_BLOCKO(0) |
-			  FDMA_DCB_STATUS_BLOCKL(len);
-}
-
-static void lan966x_fdma_tx_start(struct lan966x_tx *tx, int next_to_use)
+static void lan966x_fdma_tx_start(struct lan966x_tx *tx)
 {
 	struct lan966x *lan966x = tx->lan966x;
-	struct lan966x_tx_dcb *dcb;
 
 	if (likely(lan966x->tx.activated)) {
-		/* Connect current dcb to the next db */
-		dcb = &tx->dcbs[tx->last_in_use];
-		dcb->nextptr = tx->dma + (next_to_use *
-					  sizeof(struct lan966x_tx_dcb));
-
 		lan966x_fdma_tx_reload(tx);
 	} else {
 		/* Because it is first time, then just activate */
 		lan966x->tx.activated = true;
 		lan966x_fdma_tx_activate(tx);
 	}
-
-	/* Move to next dcb because this last in use */
-	tx->last_in_use = next_to_use;
 }
 
 int lan966x_fdma_xmit_xdpf(struct lan966x_port *port, void *ptr, u32 len)
@@ -752,11 +647,6 @@ int lan966x_fdma_xmit_xdpf(struct lan966x_port *port, void *ptr, u32 len)
 
 		next_dcb_buf->data.xdpf = xdpf;
 		next_dcb_buf->len = xdpf->len + IFH_LEN_BYTES;
-
-		/* Setup next dcb */
-		lan966x_fdma_tx_setup_dcb(tx, next_to_use,
-					  xdpf->len + IFH_LEN_BYTES,
-					  dma_addr);
 	} else {
 		page = ptr;
 
@@ -773,11 +663,6 @@ int lan966x_fdma_xmit_xdpf(struct lan966x_port *port, void *ptr, u32 len)
 
 		next_dcb_buf->data.page = page;
 		next_dcb_buf->len = len + IFH_LEN_BYTES;
-
-		/* Setup next dcb */
-		lan966x_fdma_tx_setup_dcb(tx, next_to_use,
-					  len + IFH_LEN_BYTES,
-					  dma_addr + XDP_PACKET_HEADROOM);
 	}
 
 	/* Fill up the buffer */
@@ -788,8 +673,19 @@ int lan966x_fdma_xmit_xdpf(struct lan966x_port *port, void *ptr, u32 len)
 	next_dcb_buf->ptp = false;
 	next_dcb_buf->dev = port->dev;
 
+	__fdma_dcb_add(&tx->fdma,
+		       next_to_use,
+		       0,
+		       FDMA_DCB_STATUS_INTR |
+		       FDMA_DCB_STATUS_SOF |
+		       FDMA_DCB_STATUS_EOF |
+		       FDMA_DCB_STATUS_BLOCKO(0) |
+		       FDMA_DCB_STATUS_BLOCKL(next_dcb_buf->len),
+		       &fdma_nextptr_cb,
+		       &lan966x_fdma_xdp_tx_dataptr_cb);
+
 	/* Start the transmission */
-	lan966x_fdma_tx_start(tx, next_to_use);
+	lan966x_fdma_tx_start(tx);
 
 out:
 	spin_unlock(&lan966x->tx_lock);
@@ -847,9 +743,6 @@ int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev)
 		goto release;
 	}
 
-	/* Setup next dcb */
-	lan966x_fdma_tx_setup_dcb(tx, next_to_use, skb->len, dma_addr);
-
 	/* Fill up the buffer */
 	next_dcb_buf = &tx->dcbs_buf[next_to_use];
 	next_dcb_buf->use_skb = true;
@@ -861,12 +754,21 @@ int lan966x_fdma_xmit(struct sk_buff *skb, __be32 *ifh, struct net_device *dev)
 	next_dcb_buf->ptp = false;
 	next_dcb_buf->dev = dev;
 
+	fdma_dcb_add(&tx->fdma,
+		     next_to_use,
+		     0,
+		     FDMA_DCB_STATUS_INTR |
+		     FDMA_DCB_STATUS_SOF |
+		     FDMA_DCB_STATUS_EOF |
+		     FDMA_DCB_STATUS_BLOCKO(0) |
+		     FDMA_DCB_STATUS_BLOCKL(skb->len));
+
 	if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP &&
 	    LAN966X_SKB_CB(skb)->rew_op == IFH_REW_OP_TWO_STEP_PTP)
 		next_dcb_buf->ptp = true;
 
 	/* Start the transmission */
-	lan966x_fdma_tx_start(tx, next_to_use);
+	lan966x_fdma_tx_start(tx);
 
 	return NETDEV_TX_OK;
 
@@ -908,14 +810,11 @@ static int lan966x_qsys_sw_status(struct lan966x *lan966x)
 static int lan966x_fdma_reload(struct lan966x *lan966x, int new_mtu)
 {
 	struct page_pool *page_pool;
-	dma_addr_t rx_dma;
-	void *rx_dcbs;
-	u32 size;
+	struct fdma fdma_rx_old;
 	int err;
 
 	/* Store these for later to free them */
-	rx_dma = lan966x->rx.dma;
-	rx_dcbs = lan966x->rx.dcbs;
+	memcpy(&fdma_rx_old, &lan966x->rx.fdma, sizeof(struct fdma));
 	page_pool = lan966x->rx.page_pool;
 
 	napi_synchronize(&lan966x->napi);
@@ -931,9 +830,7 @@ static int lan966x_fdma_reload(struct lan966x *lan966x, int new_mtu)
 		goto restore;
 	lan966x_fdma_rx_start(&lan966x->rx);
 
-	size = sizeof(struct lan966x_rx_dcb) * FDMA_DCB_MAX;
-	size = ALIGN(size, PAGE_SIZE);
-	dma_free_coherent(lan966x->dev, size, rx_dcbs, rx_dma);
+	fdma_free_coherent(lan966x->dev, &fdma_rx_old);
 
 	page_pool_destroy(page_pool);
 
@@ -943,8 +840,7 @@ static int lan966x_fdma_reload(struct lan966x *lan966x, int new_mtu)
 	return err;
 restore:
 	lan966x->rx.page_pool = page_pool;
-	lan966x->rx.dma = rx_dma;
-	lan966x->rx.dcbs = rx_dcbs;
+	memcpy(&lan966x->rx.fdma, &fdma_rx_old, sizeof(struct fdma));
 	lan966x_fdma_rx_start(&lan966x->rx);
 
 	return err;
@@ -1034,11 +930,24 @@ int lan966x_fdma_init(struct lan966x *lan966x)
 		return 0;
 
 	lan966x->rx.lan966x = lan966x;
-	lan966x->rx.channel_id = FDMA_XTR_CHANNEL;
+	lan966x->rx.fdma.channel_id = FDMA_XTR_CHANNEL;
+	lan966x->rx.fdma.n_dcbs = FDMA_DCB_MAX;
+	lan966x->rx.fdma.n_dbs = FDMA_RX_DCB_MAX_DBS;
+	lan966x->rx.fdma.priv = lan966x;
+	lan966x->rx.fdma.size = fdma_get_size(&lan966x->rx.fdma);
+	lan966x->rx.fdma.db_size = PAGE_SIZE << lan966x->rx.page_order;
+	lan966x->rx.fdma.ops.nextptr_cb = &fdma_nextptr_cb;
+	lan966x->rx.fdma.ops.dataptr_cb = &lan966x_fdma_rx_dataptr_cb;
 	lan966x->rx.max_mtu = lan966x_fdma_get_max_frame(lan966x);
 	lan966x->tx.lan966x = lan966x;
-	lan966x->tx.channel_id = FDMA_INJ_CHANNEL;
-	lan966x->tx.last_in_use = -1;
+	lan966x->tx.fdma.channel_id = FDMA_INJ_CHANNEL;
+	lan966x->tx.fdma.n_dcbs = FDMA_DCB_MAX;
+	lan966x->tx.fdma.n_dbs = FDMA_TX_DCB_MAX_DBS;
+	lan966x->tx.fdma.priv = lan966x;
+	lan966x->tx.fdma.size = fdma_get_size(&lan966x->tx.fdma);
+	lan966x->tx.fdma.db_size = PAGE_SIZE << lan966x->rx.page_order;
+	lan966x->tx.fdma.ops.nextptr_cb = &fdma_nextptr_cb;
+	lan966x->tx.fdma.ops.dataptr_cb = &lan966x_fdma_tx_dataptr_cb;
 
 	err = lan966x_fdma_rx_alloc(&lan966x->rx);
 	if (err)
@@ -1046,7 +955,7 @@ int lan966x_fdma_init(struct lan966x *lan966x)
 
 	err = lan966x_fdma_tx_alloc(&lan966x->tx);
 	if (err) {
-		lan966x_fdma_rx_free(&lan966x->rx);
+		fdma_free_coherent(lan966x->dev, &lan966x->rx.fdma);
 		return err;
 	}
 
@@ -1067,7 +976,7 @@ void lan966x_fdma_deinit(struct lan966x *lan966x)
 	napi_disable(&lan966x->napi);
 
 	lan966x_fdma_rx_free_pages(&lan966x->rx);
-	lan966x_fdma_rx_free(&lan966x->rx);
+	fdma_free_coherent(lan966x->dev, &lan966x->rx.fdma);
 	page_pool_destroy(lan966x->rx.page_pool);
 	lan966x_fdma_tx_free(&lan966x->tx);
 }

drivers/net/ethernet/microchip/lan966x/lan966x_main.h

@@ -16,6 +16,7 @@
 #include <net/switchdev.h>
 #include <net/xdp.h>
 
+#include <fdma_api.h>
 #include <vcap_api.h>
 #include <vcap_api_client.h>
 
@@ -76,15 +77,6 @@
 
 #define FDMA_RX_DCB_MAX_DBS		1
 #define FDMA_TX_DCB_MAX_DBS		1
-#define FDMA_DCB_INFO_DATAL(x)		((x) & GENMASK(15, 0))
-
-#define FDMA_DCB_STATUS_BLOCKL(x)	((x) & GENMASK(15, 0))
-#define FDMA_DCB_STATUS_SOF		BIT(16)
-#define FDMA_DCB_STATUS_EOF		BIT(17)
-#define FDMA_DCB_STATUS_INTR		BIT(18)
-#define FDMA_DCB_STATUS_DONE		BIT(19)
-#define FDMA_DCB_STATUS_BLOCKO(x)	(((x) << 20) & GENMASK(31, 20))
-#define FDMA_DCB_INVALID_DATA		0x1
 
 #define FDMA_XTR_CHANNEL		6
 #define FDMA_INJ_CHANNEL		0
@@ -199,49 +191,14 @@ enum vcap_is1_port_sel_rt {
 
 struct lan966x_port;
 
-struct lan966x_db {
-	u64 dataptr;
-	u64 status;
-};
-
-struct lan966x_rx_dcb {
-	u64 nextptr;
-	u64 info;
-	struct lan966x_db db[FDMA_RX_DCB_MAX_DBS];
-};
-
-struct lan966x_tx_dcb {
-	u64 nextptr;
-	u64 info;
-	struct lan966x_db db[FDMA_TX_DCB_MAX_DBS];
-};
-
 struct lan966x_rx {
 	struct lan966x *lan966x;
 
-	/* Pointer to the array of hardware dcbs. */
-	struct lan966x_rx_dcb *dcbs;
-
-	/* Pointer to the last address in the dcbs. */
-	struct lan966x_rx_dcb *last_entry;
+	struct fdma fdma;
 
 	/* For each DB, there is a page */
 	struct page *page[FDMA_DCB_MAX][FDMA_RX_DCB_MAX_DBS];
 
-	/* Represents the db_index, it can have a value between 0 and
-	 * FDMA_RX_DCB_MAX_DBS, once it reaches the value of FDMA_RX_DCB_MAX_DBS
-	 * it means that the DCB can be reused.
-	 */
-	int db_index;
-
-	/* Represents the index in the dcbs. It has a value between 0 and
-	 * FDMA_DCB_MAX
-	 */
-	int dcb_index;
-
-	/* Represents the dma address to the dcbs array */
-	dma_addr_t dma;
-
 	/* Represents the page order that is used to allocate the pages for the
 	 * RX buffers. This value is calculated based on max MTU of the devices.
 	 */
@@ -252,8 +209,6 @@ struct lan966x_rx {
 	 */
 	u32 max_mtu;
 
-	u8 channel_id;
-
 	struct page_pool *page_pool;
 };
 
@@ -275,18 +230,11 @@ struct lan966x_tx_dcb_buf {
 struct lan966x_tx {
 	struct lan966x *lan966x;
 
-	/* Pointer to the dcb list */
-	struct lan966x_tx_dcb *dcbs;
-	u16 last_in_use;
-
-	/* Represents the DMA address to the first entry of the dcb entries. */
-	dma_addr_t dma;
+	struct fdma fdma;
 
 	/* Array of dcbs that are given to the HW */
 	struct lan966x_tx_dcb_buf *dcbs_buf;
 
-	u8 channel_id;
-
 	bool activated;
 };