[PATCH net-next v2 0/2] net: airoha: Improve hwfd buffer/descriptor queues setup

[PATCH net-next v2 0/2] net: airoha: Improve hwfd buffer/descriptor queues setup

[Lorenzo Bianconi]

Compute the number of hwfd buffers/descriptors according to the reserved
memory size if provided via DTS.
Reduce the required hwfd buffers queue size for QDMA1.

---
Changes in v2:
- Rely on div_u64 to compute number of hw descriptors
- Link to v1: https://lore.kernel.org/r/20250615-airoha-hw-num-desc-v1-0-8f88daa4abd7@kernel.org

---
Lorenzo Bianconi (2):
      net: airoha: Compute number of descriptors according to reserved memory size
      net: airoha: Differentiate hwfd buffer size for QDMA0 and QDMA1

 drivers/net/ethernet/airoha/airoha_eth.c | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)
---
base-commit: 8909f5f4ecd551c2299b28e05254b77424c8c7dc
change-id: 20250614-airoha-hw-num-desc-019c07061c42

Best regards,
-- 
Lorenzo Bianconi <lorenzo@kernel.org>

[PATCH net-next v2 1/2] net: airoha: Compute number of descriptors according to reserved memory size

[Lorenzo Bianconi]

In order to not exceed the reserved memory size for hwfd buffers,
compute the number of hwfd buffers/descriptors according to the
reserved memory size and the size of each hwfd buffer (2KB).

Fixes: 3a1ce9e3d01b ("net: airoha: Add the capability to allocate hwfd buffers via reserved-memory")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/airoha/airoha_eth.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index a7ec609d64dee9c8e901c7eb650bb3fe144ee00a..1b7fd7ee0cbf3e1f7717110c70e9c5183fdd93d4 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -1065,19 +1065,13 @@ static void airoha_qdma_cleanup_tx_queue(struct airoha_queue *q)
 
 static int airoha_qdma_init_hfwd_queues(struct airoha_qdma *qdma)
 {
+	int size, index, num_desc = HW_DSCP_NUM;
 	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;
 
-	size = HW_DSCP_NUM * sizeof(struct airoha_qdma_fwd_desc);
-	if (!dmam_alloc_coherent(eth->dev, size, &dma_addr, GFP_KERNEL))
-		return -ENOMEM;
-
-	airoha_qdma_wr(qdma, REG_FWD_DSCP_BASE, dma_addr);
-
 	name = devm_kasprintf(eth->dev, GFP_KERNEL, "qdma%d-buf", id);
 	if (!name)
 		return -ENOMEM;
@@ -1099,8 +1093,12 @@ static int airoha_qdma_init_hfwd_queues(struct airoha_qdma *qdma)
 		rmem = of_reserved_mem_lookup(np);
 		of_node_put(np);
 		dma_addr = rmem->base;
+		/* Compute the number of hw descriptors according to the
+		 * reserved memory size and the payload buffer size
+		 */
+		num_desc = rmem->size / AIROHA_MAX_PACKET_SIZE;
 	} else {
-		size = AIROHA_MAX_PACKET_SIZE * HW_DSCP_NUM;
+		size = AIROHA_MAX_PACKET_SIZE * num_desc;
 		if (!dmam_alloc_coherent(eth->dev, size, &dma_addr,
 					 GFP_KERNEL))
 			return -ENOMEM;
@@ -1108,6 +1106,11 @@ static int airoha_qdma_init_hfwd_queues(struct airoha_qdma *qdma)
 
 	airoha_qdma_wr(qdma, REG_FWD_BUF_BASE, dma_addr);
 
+	size = num_desc * sizeof(struct airoha_qdma_fwd_desc);
+	if (!dmam_alloc_coherent(eth->dev, size, &dma_addr, GFP_KERNEL))
+		return -ENOMEM;
+
+	airoha_qdma_wr(qdma, REG_FWD_DSCP_BASE, dma_addr);
 	airoha_qdma_rmw(qdma, REG_HW_FWD_DSCP_CFG,
 			HW_FWD_DSCP_PAYLOAD_SIZE_MASK,
 			FIELD_PREP(HW_FWD_DSCP_PAYLOAD_SIZE_MASK, 0));
@@ -1116,7 +1119,7 @@ static int airoha_qdma_init_hfwd_queues(struct airoha_qdma *qdma)
 	airoha_qdma_rmw(qdma, REG_LMGR_INIT_CFG,
 			LMGR_INIT_START | LMGR_SRAM_MODE_MASK |
 			HW_FWD_DESC_NUM_MASK,
-			FIELD_PREP(HW_FWD_DESC_NUM_MASK, HW_DSCP_NUM) |
+			FIELD_PREP(HW_FWD_DESC_NUM_MASK, num_desc) |
 			LMGR_INIT_START | LMGR_SRAM_MODE_MASK);
 
 	return read_poll_timeout(airoha_qdma_rr, status,

-- 
2.49.0

[PATCH net-next v2 2/2] net: airoha: Differentiate hwfd buffer size for QDMA0 and QDMA1

[Lorenzo Bianconi]

In oreder to reduce the required hwfd buffers queue size for QDMA1,
differentiate hwfd buffer size for QDMA0 and QDMA1 and use 2KB for QDMA0
and 1KB for QDMA1.

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/airoha/airoha_eth.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c
index 1b7fd7ee0cbf3e1f7717110c70e9c5183fdd93d4..06dea3a13e77ce11f35dbd36966a34c5ef229c11 100644
--- a/drivers/net/ethernet/airoha/airoha_eth.c
+++ b/drivers/net/ethernet/airoha/airoha_eth.c
@@ -1068,14 +1068,15 @@ static int airoha_qdma_init_hfwd_queues(struct airoha_qdma *qdma)
 	int size, index, num_desc = HW_DSCP_NUM;
 	struct airoha_eth *eth = qdma->eth;
 	int id = qdma - &eth->qdma[0];
+	u32 status, buf_size;
 	dma_addr_t dma_addr;
 	const char *name;
-	u32 status;
 
 	name = devm_kasprintf(eth->dev, GFP_KERNEL, "qdma%d-buf", id);
 	if (!name)
 		return -ENOMEM;
 
+	buf_size = id ? AIROHA_MAX_PACKET_SIZE / 2 : AIROHA_MAX_PACKET_SIZE;
 	index = of_property_match_string(eth->dev->of_node,
 					 "memory-region-names", name);
 	if (index >= 0) {
@@ -1096,9 +1097,9 @@ static int airoha_qdma_init_hfwd_queues(struct airoha_qdma *qdma)
 		/* Compute the number of hw descriptors according to the
 		 * reserved memory size and the payload buffer size
 		 */
-		num_desc = rmem->size / AIROHA_MAX_PACKET_SIZE;
+		num_desc = div_u64(rmem->size, buf_size);
 	} else {
-		size = AIROHA_MAX_PACKET_SIZE * num_desc;
+		size = buf_size * num_desc;
 		if (!dmam_alloc_coherent(eth->dev, size, &dma_addr,
 					 GFP_KERNEL))
 			return -ENOMEM;
@@ -1111,9 +1112,10 @@ static int airoha_qdma_init_hfwd_queues(struct airoha_qdma *qdma)
 		return -ENOMEM;
 
 	airoha_qdma_wr(qdma, REG_FWD_DSCP_BASE, dma_addr);
+	/* QDMA0: 2KB. QDMA1: 1KB */
 	airoha_qdma_rmw(qdma, REG_HW_FWD_DSCP_CFG,
 			HW_FWD_DSCP_PAYLOAD_SIZE_MASK,
-			FIELD_PREP(HW_FWD_DSCP_PAYLOAD_SIZE_MASK, 0));
+			FIELD_PREP(HW_FWD_DSCP_PAYLOAD_SIZE_MASK, !!id));
 	airoha_qdma_rmw(qdma, REG_FWD_DSCP_LOW_THR, FWD_DSCP_LOW_THR_MASK,
 			FIELD_PREP(FWD_DSCP_LOW_THR_MASK, 128));
 	airoha_qdma_rmw(qdma, REG_LMGR_INIT_CFG,

-- 
2.49.0

Re: [PATCH net-next v2 0/2] net: airoha: Improve hwfd buffer/descriptor queues setup

[Jakub Kicinski]

On Mon, 16 Jun 2025 15:45:39 +0200 Lorenzo Bianconi wrote:
> Compute the number of hwfd buffers/descriptors according to the reserved
> memory size if provided via DTS.
> Reduce the required hwfd buffers queue size for QDMA1.

Same question regarding target tree, FWIW

Re: [PATCH net-next v2 0/2] net: airoha: Improve hwfd buffer/descriptor queues setup

[Lorenzo Bianconi]

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> On Mon, 16 Jun 2025 15:45:39 +0200 Lorenzo Bianconi wrote:
> > Compute the number of hwfd buffers/descriptors according to the reserved
> > memory size if provided via DTS.
> > Reduce the required hwfd buffers queue size for QDMA1.
> 
> Same question regarding target tree, FWIW

ack, fine. I will post v3 targeting net tree.

Regards,
Lorenzo

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