Merge branch 'add-the-capability-to-consume-sram-for-hwfd-descriptor-queue-in-airoha_eth-driver'

Lorenzo Bianconi says:

====================
Add the capability to consume SRAM for hwfd descriptor queue in airoha_eth driver

In order to improve packet processing and packet forwarding
performances, EN7581 SoC supports consuming SRAM instead of DRAM for hw
forwarding descriptors queue. For downlink hw accelerated traffic
request to consume SRAM memory for hw forwarding descriptors queue.
Moreover, in some configurations QDMA blocks require a contiguous block
of system memory for hwfd buffers queue. Introduce the capability to
allocate hw buffers forwarding queue via the reserved-memory DTS
property instead of running dmam_alloc_coherent().

v2: https://lore.kernel.org/r/20250509-airopha-desc-sram-v2-0-9dc3d8076dfb@kernel.org
v1: https://lore.kernel.org/r/20250507-airopha-desc-sram-v1-0-d42037431bfa@kernel.org
====================

Link: https://patch.msgid.link/20250521-airopha-desc-sram-v3-0-a6e9b085b4f0@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

4 files changed, 60 insertions, 24 deletions

diff --git a/Documentation/devicetree/bindings/net/airoha,en7581-eth.yaml b/Documentation/devicetree/bindings/net/airoha,en7581-eth.yaml
index 0fdd11265417..6d22131ac2f9 100644
--- a/Documentation/devicetree/bindings/net/airoha,en7581-eth.yaml
+++ b/Documentation/devicetree/bindings/net/airoha,en7581-eth.yaml
@@ -57,6 +57,16 @@ properties:
       - const: hsi-mac
       - const: xfp-mac
 
+  memory-region:
+    items:
+      - description: QDMA0 buffer memory
+      - description: QDMA1 buffer memory
+
+  memory-region-names:
+    items:
+      - const: qdma0-buf
+      - const: qdma1-buf
+
   "#address-cells":
     const: 1
 
@@ -140,6 +150,9 @@ examples:
                      <GIC_SPI 49 IRQ_TYPE_LEVEL_HIGH>,
                      <GIC_SPI 64 IRQ_TYPE_LEVEL_HIGH>;
 
+        memory-region = <&qdma0_buf>, <&qdma1_buf>;
+        memory-region-names = "qdma0-buf", "qdma1-buf";
+
         airoha,npu = <&npu>;
 
         #address-cells = <1>;
diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index 0d627e511266..507ba046c719 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -5,6 +5,7 @@
  */
 #include <linux/of.h>
 #include <linux/of_net.h>
+#include <linux/of_reserved_mem.h>
 #include <linux/platform_device.h>
 #include <linux/tcp.h>
 #include <linux/u64_stats_sync.h>
@@ -70,15 +71,6 @@ static void airoha_qdma_irq_disable(struct airoha_irq_bank *irq_bank,
 	airoha_qdma_set_irqmask(irq_bank, index, mask, 0);
 }
 
-static bool airhoa_is_lan_gdm_port(struct airoha_gdm_port *port)
-{
-	/* GDM1 port on EN7581 SoC is connected to the lan dsa switch.
-	 * GDM{2,3,4} can be used as wan port connected to an external
-	 * phy module.
-	 */
-	return port->id == 1;
-}
-
 static void airoha_set_macaddr(struct airoha_gdm_port *port, const u8 *addr)
 {
 	struct airoha_eth *eth = port->qdma->eth;
@@ -1072,24 +1064,46 @@ static void airoha_qdma_cleanup_tx_queue(struct airoha_queue *q)
 static int airoha_qdma_init_hfwd_queues(struct airoha_qdma *qdma)
 {
 	struct airoha_eth *eth = qdma->eth;
+	int id = qdma - &eth->qdma[0];
 	dma_addr_t dma_addr;
+	const char *name;
+	int size, index;
 	u32 status;
-	int size;
 
 	size = HW_DSCP_NUM * sizeof(struct airoha_qdma_fwd_desc);
-	qdma->hfwd.desc = dmam_alloc_coherent(eth->dev, size, &dma_addr,
-					      GFP_KERNEL);
-	if (!qdma->hfwd.desc)
+	if (!dmam_alloc_coherent(eth->dev, size, &dma_addr, GFP_KERNEL))
 		return -ENOMEM;
 
 	airoha_qdma_wr(qdma, REG_FWD_DSCP_BASE, dma_addr);
 
-	size = AIROHA_MAX_PACKET_SIZE * HW_DSCP_NUM;
-	qdma->hfwd.q = dmam_alloc_coherent(eth->dev, size, &dma_addr,
-					   GFP_KERNEL);
-	if (!qdma->hfwd.q)
+	name = devm_kasprintf(eth->dev, GFP_KERNEL, "qdma%d-buf", id);
+	if (!name)
 		return -ENOMEM;
 
+	index = of_property_match_string(eth->dev->of_node,
+					 "memory-region-names", name);
+	if (index >= 0) {
+		struct reserved_mem *rmem;
+		struct device_node *np;
+
+		/* Consume reserved memory for hw forwarding buffers queue if
+		 * available in the DTS
+		 */
+		np = of_parse_phandle(eth->dev->of_node, "memory-region",
+				      index);
+		if (!np)
+			return -ENODEV;
+
+		rmem = of_reserved_mem_lookup(np);
+		of_node_put(np);
+		dma_addr = rmem->base;
+	} else {
+		size = AIROHA_MAX_PACKET_SIZE * HW_DSCP_NUM;
+		if (!dmam_alloc_coherent(eth->dev, size, &dma_addr,
+					 GFP_KERNEL))
+			return -ENOMEM;
+	}
+
 	airoha_qdma_wr(qdma, REG_FWD_BUF_BASE, dma_addr);
 
 	airoha_qdma_rmw(qdma, REG_HW_FWD_DSCP_CFG,
@@ -1101,7 +1115,7 @@ static int airoha_qdma_init_hfwd_queues(struct airoha_qdma *qdma)
 			LMGR_INIT_START | LMGR_SRAM_MODE_MASK |
 			HW_FWD_DESC_NUM_MASK,
 			FIELD_PREP(HW_FWD_DESC_NUM_MASK, HW_DSCP_NUM) |
-			LMGR_INIT_START);
+			LMGR_INIT_START | LMGR_SRAM_MODE_MASK);
 
 	return read_poll_timeout(airoha_qdma_rr, status,
 				 !(status & LMGR_INIT_START), USEC_PER_MSEC,
diff --git a/drivers/net/ethernet/airoha/airoha_eth.h b/drivers/net/ethernet/airoha/airoha_eth.h
index 531a3c49c156..b815697302bf 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.h
+++ b/drivers/net/ethernet/airoha/airoha_eth.h
@@ -513,12 +513,6 @@ struct airoha_qdma {
 
 	struct airoha_queue q_tx[AIROHA_NUM_TX_RING];
 	struct airoha_queue q_rx[AIROHA_NUM_RX_RING];
-
-	/* descriptor and packet buffers for qdma hw forward */
-	struct {
-		void *desc;
-		void *q;
-	} hfwd;
 };
 
 struct airoha_gdm_port {
@@ -603,6 +597,15 @@ u32 airoha_rmw(void __iomem *base, u32 offset, u32 mask, u32 val);
 #define airoha_qdma_clear(qdma, offset, val)			\
 	airoha_rmw((qdma)->regs, (offset), (val), 0)
 
+static inline bool airhoa_is_lan_gdm_port(struct airoha_gdm_port *port)
+{
+	/* GDM1 port on EN7581 SoC is connected to the lan dsa switch.
+	 * GDM{2,3,4} can be used as wan port connected to an external
+	 * phy module.
+	 */
+	return port->id == 1;
+}
+
 bool airoha_is_valid_gdm_port(struct airoha_eth *eth,
 			      struct airoha_gdm_port *port);
 
diff --git a/drivers/net/ethernet/airoha/airoha_ppe.c b/drivers/net/ethernet/airoha/airoha_ppe.c
index 2d273937f19c..12d32c92717a 100644
--- a/drivers/net/ethernet/airoha/airoha_ppe.c
+++ b/drivers/net/ethernet/airoha/airoha_ppe.c
@@ -251,6 +251,12 @@ static int airoha_ppe_foe_entry_prepare(struct airoha_eth *eth,
 		else
 			pse_port = 2; /* uplink relies on GDM2 loopback */
 		val |= FIELD_PREP(AIROHA_FOE_IB2_PSE_PORT, pse_port);
+
+		/* For downlink traffic consume SRAM memory for hw forwarding
+		 * descriptors queue.
+		 */
+		if (airhoa_is_lan_gdm_port(port))
+			val |= AIROHA_FOE_IB2_FAST_PATH;
 	}
 
 	if (is_multicast_ether_addr(data->eth.h_dest))