From f7ac9a0bbe3f15d0164ac09688e336933cb54a03 Mon Sep 17 00:00:00 2001
From: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Date: Wed, 19 Nov 2025 10:23:14 +0000
Subject: [PATCH 1/6] net: stmmac: dwc-qos-eth: simplify switch() in
 dwc_eth_dwmac_config_dt()

Simplify the switch() statement in dwc_eth_dwmac_config_dt().
Although this is not speed-critical, simplifying it can make it more
readable. This also drastically improves the code emitted by the
compiler.

On aarch64, with the original code, the compiler loads registers with
every possible value, and then has a tree of test-and-branch statements
to work out which register to store. With the simplified code, the
compiler can load a register with '4' and shift it appropriately.

This shrinks the text size on aarch64 from 4289 bytes to 4153 bytes,
a reduction of 3%.

Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vLfLG-0000000FMai-3fKz@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 .../stmicro/stmmac/dwmac-dwc-qos-eth.c        | 26 +++----------------
 1 file changed, 3 insertions(+), 23 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
index c7cd6497d42d..e6d5893c5905 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
@@ -84,29 +84,9 @@ static int dwc_eth_dwmac_config_dt(struct platform_device *pdev,
 	device_property_read_u32(dev, "snps,burst-map", &burst_map);
 
 	/* converts burst-map bitmask to burst array */
-	for (bit_index = 0; bit_index < 7; bit_index++) {
-		if (burst_map & (1 << bit_index)) {
-			switch (bit_index) {
-			case 0:
-			plat_dat->axi->axi_blen[a_index] = 4; break;
-			case 1:
-			plat_dat->axi->axi_blen[a_index] = 8; break;
-			case 2:
-			plat_dat->axi->axi_blen[a_index] = 16; break;
-			case 3:
-			plat_dat->axi->axi_blen[a_index] = 32; break;
-			case 4:
-			plat_dat->axi->axi_blen[a_index] = 64; break;
-			case 5:
-			plat_dat->axi->axi_blen[a_index] = 128; break;
-			case 6:
-			plat_dat->axi->axi_blen[a_index] = 256; break;
-			default:
-			break;
-			}
-			a_index++;
-		}
-	}
+	for (bit_index = 0; bit_index < 7; bit_index++)
+		if (burst_map & (1 << bit_index))
+			plat_dat->axi->axi_blen[a_index++] = 4 << bit_index;
 
 	/* dwc-qos needs GMAC4, AAL, TSO and PMT */
 	plat_dat->core_type = DWMAC_CORE_GMAC4;

From 8c696659f47aa4f4e5f35808b416664378930dd9 Mon Sep 17 00:00:00 2001
From: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Date: Wed, 19 Nov 2025 10:23:19 +0000
Subject: [PATCH 2/6] net: stmmac: move common DMA AXI register bits to
 common.h

Move the common DMA AXI register bits to common.h so they can be shared
and we can provide a common function to convert the axi->dma_blen[]
array to the format needed for this register.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vLfLL-0000000FMap-49gf@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/stmicro/stmmac/common.h     | 10 ++++++++++
 drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h |  9 +--------
 drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h  | 11 ++---------
 drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h   | 16 ++++++++--------
 4 files changed, 21 insertions(+), 25 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
index 7395bbb94aea..3c6e7fe7b999 100644
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -548,6 +548,16 @@ struct dma_features {
 #define LPI_CTRL_STATUS_TLPIEX	BIT(1)	/* Transmit LPI Exit */
 #define LPI_CTRL_STATUS_TLPIEN	BIT(0)	/* Transmit LPI Entry */
 
+/* Common definitions for AXI Master Bus Mode */
+#define DMA_AXI_AAL		BIT(12)
+#define DMA_AXI_BLEN256		BIT(7)
+#define DMA_AXI_BLEN128		BIT(6)
+#define DMA_AXI_BLEN64		BIT(5)
+#define DMA_AXI_BLEN32		BIT(4)
+#define DMA_AXI_BLEN16		BIT(3)
+#define DMA_AXI_BLEN8		BIT(2)
+#define DMA_AXI_BLEN4		BIT(1)
+
 #define STMMAC_CHAIN_MODE	0x1
 #define STMMAC_RING_MODE	0x2
 
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h
index 4f980dcd3958..dfcb7ce79e76 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h
@@ -69,15 +69,8 @@
 
 #define DMA_SYS_BUS_MB			BIT(14)
 #define DMA_AXI_1KBBE			BIT(13)
-#define DMA_SYS_BUS_AAL			BIT(12)
+#define DMA_SYS_BUS_AAL			DMA_AXI_AAL
 #define DMA_SYS_BUS_EAME		BIT(11)
-#define DMA_AXI_BLEN256			BIT(7)
-#define DMA_AXI_BLEN128			BIT(6)
-#define DMA_AXI_BLEN64			BIT(5)
-#define DMA_AXI_BLEN32			BIT(4)
-#define DMA_AXI_BLEN16			BIT(3)
-#define DMA_AXI_BLEN8			BIT(2)
-#define DMA_AXI_BLEN4			BIT(1)
 #define DMA_SYS_BUS_FB			BIT(0)
 
 #define DMA_BURST_LEN_DEFAULT		(DMA_AXI_BLEN256 | DMA_AXI_BLEN128 | \
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h b/drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h
index 5d9c18f5bbf5..967a735e9a0b 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h
@@ -68,20 +68,13 @@ static inline u32 dma_chan_base_addr(u32 base, u32 chan)
 #define DMA_AXI_OSR_MAX		0xf
 #define DMA_AXI_MAX_OSR_LIMIT ((DMA_AXI_OSR_MAX << DMA_AXI_WR_OSR_LMT_SHIFT) | \
 			       (DMA_AXI_OSR_MAX << DMA_AXI_RD_OSR_LMT_SHIFT))
-#define	DMA_AXI_1KBBE		BIT(13)
-#define DMA_AXI_AAL		BIT(12)
-#define DMA_AXI_BLEN256		BIT(7)
-#define DMA_AXI_BLEN128		BIT(6)
-#define DMA_AXI_BLEN64		BIT(5)
-#define DMA_AXI_BLEN32		BIT(4)
-#define DMA_AXI_BLEN16		BIT(3)
-#define DMA_AXI_BLEN8		BIT(2)
-#define DMA_AXI_BLEN4		BIT(1)
 #define DMA_BURST_LEN_DEFAULT	(DMA_AXI_BLEN256 | DMA_AXI_BLEN128 | \
 				 DMA_AXI_BLEN64 | DMA_AXI_BLEN32 | \
 				 DMA_AXI_BLEN16 | DMA_AXI_BLEN8 | \
 				 DMA_AXI_BLEN4)
 
+#define	DMA_AXI_1KBBE		BIT(13)
+
 #define DMA_AXI_UNDEF		BIT(0)
 
 #define DMA_AXI_BURST_LEN_MASK	0x000000FE
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
index e48cfa05000c..16c6d03fc929 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
@@ -338,16 +338,16 @@
 #define XGMAC_RD_OSR_LMT_SHIFT		16
 #define XGMAC_EN_LPI			BIT(15)
 #define XGMAC_LPI_XIT_PKT		BIT(14)
-#define XGMAC_AAL			BIT(12)
+#define XGMAC_AAL			DMA_AXI_AAL
 #define XGMAC_EAME			BIT(11)
 #define XGMAC_BLEN			GENMASK(7, 1)
-#define XGMAC_BLEN256			BIT(7)
-#define XGMAC_BLEN128			BIT(6)
-#define XGMAC_BLEN64			BIT(5)
-#define XGMAC_BLEN32			BIT(4)
-#define XGMAC_BLEN16			BIT(3)
-#define XGMAC_BLEN8			BIT(2)
-#define XGMAC_BLEN4			BIT(1)
+#define XGMAC_BLEN256			DMA_AXI_BLEN256
+#define XGMAC_BLEN128			DMA_AXI_BLEN128
+#define XGMAC_BLEN64			DMA_AXI_BLEN64
+#define XGMAC_BLEN32			DMA_AXI_BLEN32
+#define XGMAC_BLEN16			DMA_AXI_BLEN16
+#define XGMAC_BLEN8			DMA_AXI_BLEN8
+#define XGMAC_BLEN4			DMA_AXI_BLEN4
 #define XGMAC_UNDEF			BIT(0)
 #define XGMAC_TX_EDMA_CTRL		0x00003040
 #define XGMAC_TDPS			GENMASK(29, 0)

From 2704af20c8e5e7f5f1cfb56003d246a7936458f6 Mon Sep 17 00:00:00 2001
From: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Date: Wed, 19 Nov 2025 10:23:25 +0000
Subject: [PATCH 3/6] net: stmmac: provide common stmmac_axi_blen_to_mask()

Provide a common stmmac_axi_blen_to_mask() function to translate the
burst length array to the value for the AXI bus mode register, and use
it for dwmac, dwmac4 and dwxgmac2. Remove the now unnecessary
XGMAC_BLEN* definitions.

Note that stmmac_axi_blen_to_dma_mask() is coded to be more efficient
than the original three implementations, and verifies the contents of
the burst length array.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vLfLR-0000000FMav-0VL6@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/stmicro/stmmac/common.h  |  3 ++
 .../ethernet/stmicro/stmmac/dwmac1000_dma.c   | 31 ++--------------
 .../net/ethernet/stmicro/stmmac/dwmac4_dma.c  | 31 ++--------------
 .../net/ethernet/stmicro/stmmac/dwmac4_dma.h  |  2 -
 .../net/ethernet/stmicro/stmmac/dwmac_dma.h   |  2 -
 .../net/ethernet/stmicro/stmmac/dwxgmac2.h    |  9 +----
 .../ethernet/stmicro/stmmac/dwxgmac2_dma.c    | 34 ++++-------------
 .../net/ethernet/stmicro/stmmac/stmmac_main.c | 37 +++++++++++++++++++
 8 files changed, 56 insertions(+), 93 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
index 3c6e7fe7b999..49df46be3669 100644
--- a/drivers/net/ethernet/stmicro/stmmac/common.h
+++ b/drivers/net/ethernet/stmicro/stmmac/common.h
@@ -557,6 +557,9 @@ struct dma_features {
 #define DMA_AXI_BLEN16		BIT(3)
 #define DMA_AXI_BLEN8		BIT(2)
 #define DMA_AXI_BLEN4		BIT(1)
+#define DMA_AXI_BLEN_MASK	GENMASK(7, 1)
+
+void stmmac_axi_blen_to_mask(u32 *regval, const u32 *blen, size_t len);
 
 #define STMMAC_CHAIN_MODE	0x1
 #define STMMAC_RING_MODE	0x2
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
index 118a22406a2e..b6476a1bfeab 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
@@ -19,7 +19,6 @@
 static void dwmac1000_dma_axi(void __iomem *ioaddr, struct stmmac_axi *axi)
 {
 	u32 value = readl(ioaddr + DMA_AXI_BUS_MODE);
-	int i;
 
 	pr_info("dwmac1000: Master AXI performs %s burst length\n",
 		!(value & DMA_AXI_UNDEF) ? "fixed" : "any");
@@ -39,33 +38,11 @@ static void dwmac1000_dma_axi(void __iomem *ioaddr, struct stmmac_axi *axi)
 
 	/* Depending on the UNDEF bit the Master AXI will perform any burst
 	 * length according to the BLEN programmed (by default all BLEN are
-	 * set).
+	 * set). Note that the UNDEF bit is readonly, and is the inverse of
+	 * Bus Mode bit 16.
 	 */
-	for (i = 0; i < AXI_BLEN; i++) {
-		switch (axi->axi_blen[i]) {
-		case 256:
-			value |= DMA_AXI_BLEN256;
-			break;
-		case 128:
-			value |= DMA_AXI_BLEN128;
-			break;
-		case 64:
-			value |= DMA_AXI_BLEN64;
-			break;
-		case 32:
-			value |= DMA_AXI_BLEN32;
-			break;
-		case 16:
-			value |= DMA_AXI_BLEN16;
-			break;
-		case 8:
-			value |= DMA_AXI_BLEN8;
-			break;
-		case 4:
-			value |= DMA_AXI_BLEN4;
-			break;
-		}
-	}
+	stmmac_axi_blen_to_mask(&value, axi->axi_blen,
+				ARRAY_SIZE(axi->axi_blen));
 
 	writel(value, ioaddr + DMA_AXI_BUS_MODE);
 }
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
index d87a8b595e6a..90d03c7b29f4 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
@@ -18,7 +18,6 @@
 static void dwmac4_dma_axi(void __iomem *ioaddr, struct stmmac_axi *axi)
 {
 	u32 value = readl(ioaddr + DMA_SYS_BUS_MODE);
-	int i;
 
 	pr_info("dwmac4: Master AXI performs %s burst length\n",
 		(value & DMA_SYS_BUS_FB) ? "fixed" : "any");
@@ -38,33 +37,11 @@ static void dwmac4_dma_axi(void __iomem *ioaddr, struct stmmac_axi *axi)
 
 	/* Depending on the UNDEF bit the Master AXI will perform any burst
 	 * length according to the BLEN programmed (by default all BLEN are
-	 * set).
+	 * set). Note that the UNDEF bit is readonly, and is the inverse of
+	 * Bus Mode bit 16.
 	 */
-	for (i = 0; i < AXI_BLEN; i++) {
-		switch (axi->axi_blen[i]) {
-		case 256:
-			value |= DMA_AXI_BLEN256;
-			break;
-		case 128:
-			value |= DMA_AXI_BLEN128;
-			break;
-		case 64:
-			value |= DMA_AXI_BLEN64;
-			break;
-		case 32:
-			value |= DMA_AXI_BLEN32;
-			break;
-		case 16:
-			value |= DMA_AXI_BLEN16;
-			break;
-		case 8:
-			value |= DMA_AXI_BLEN8;
-			break;
-		case 4:
-			value |= DMA_AXI_BLEN4;
-			break;
-		}
-	}
+	stmmac_axi_blen_to_mask(&value, axi->axi_blen,
+				ARRAY_SIZE(axi->axi_blen));
 
 	writel(value, ioaddr + DMA_SYS_BUS_MODE);
 }
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h
index dfcb7ce79e76..f27126f05551 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h
@@ -78,8 +78,6 @@
 					DMA_AXI_BLEN16 | DMA_AXI_BLEN8 | \
 					DMA_AXI_BLEN4)
 
-#define DMA_AXI_BURST_LEN_MASK		0x000000FE
-
 /* DMA TBS Control */
 #define DMA_TBS_FTOS			GENMASK(31, 8)
 #define DMA_TBS_FTOV			BIT(0)
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h b/drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h
index 967a735e9a0b..d1c149f7a3dd 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac_dma.h
@@ -77,8 +77,6 @@ static inline u32 dma_chan_base_addr(u32 base, u32 chan)
 
 #define DMA_AXI_UNDEF		BIT(0)
 
-#define DMA_AXI_BURST_LEN_MASK	0x000000FE
-
 #define DMA_CUR_TX_BUF_ADDR	0x00001050	/* Current Host Tx Buffer */
 #define DMA_CUR_RX_BUF_ADDR	0x00001054	/* Current Host Rx Buffer */
 #define DMA_HW_FEATURE		0x00001058	/* HW Feature Register */
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
index 16c6d03fc929..fecda3034d36 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2.h
@@ -340,14 +340,7 @@
 #define XGMAC_LPI_XIT_PKT		BIT(14)
 #define XGMAC_AAL			DMA_AXI_AAL
 #define XGMAC_EAME			BIT(11)
-#define XGMAC_BLEN			GENMASK(7, 1)
-#define XGMAC_BLEN256			DMA_AXI_BLEN256
-#define XGMAC_BLEN128			DMA_AXI_BLEN128
-#define XGMAC_BLEN64			DMA_AXI_BLEN64
-#define XGMAC_BLEN32			DMA_AXI_BLEN32
-#define XGMAC_BLEN16			DMA_AXI_BLEN16
-#define XGMAC_BLEN8			DMA_AXI_BLEN8
-#define XGMAC_BLEN4			DMA_AXI_BLEN4
+/* XGMAC_BLEN* are now defined as DMA_AXI_BLEN* in common.h */
 #define XGMAC_UNDEF			BIT(0)
 #define XGMAC_TX_EDMA_CTRL		0x00003040
 #define XGMAC_TDPS			GENMASK(29, 0)
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
index 4d6bb995d8d8..8a2cb6ca9588 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
@@ -84,7 +84,6 @@ static void dwxgmac2_dma_init_tx_chan(struct stmmac_priv *priv,
 static void dwxgmac2_dma_axi(void __iomem *ioaddr, struct stmmac_axi *axi)
 {
 	u32 value = readl(ioaddr + XGMAC_DMA_SYSBUS_MODE);
-	int i;
 
 	if (axi->axi_lpi_en)
 		value |= XGMAC_EN_LPI;
@@ -102,32 +101,13 @@ static void dwxgmac2_dma_axi(void __iomem *ioaddr, struct stmmac_axi *axi)
 	if (!axi->axi_fb)
 		value |= XGMAC_UNDEF;
 
-	value &= ~XGMAC_BLEN;
-	for (i = 0; i < AXI_BLEN; i++) {
-		switch (axi->axi_blen[i]) {
-		case 256:
-			value |= XGMAC_BLEN256;
-			break;
-		case 128:
-			value |= XGMAC_BLEN128;
-			break;
-		case 64:
-			value |= XGMAC_BLEN64;
-			break;
-		case 32:
-			value |= XGMAC_BLEN32;
-			break;
-		case 16:
-			value |= XGMAC_BLEN16;
-			break;
-		case 8:
-			value |= XGMAC_BLEN8;
-			break;
-		case 4:
-			value |= XGMAC_BLEN4;
-			break;
-		}
-	}
+	/* Depending on the UNDEF bit the Master AXI will perform any burst
+	 * length according to the BLEN programmed (by default all BLEN are
+	 * set). Note that the UNDEF bit is readonly, and is the inverse of
+	 * Bus Mode bit 16.
+	 */
+	stmmac_axi_blen_to_mask(&value, axi->axi_blen,
+				ARRAY_SIZE(axi->axi_blen));
 
 	writel(value, ioaddr + XGMAC_DMA_SYSBUS_MODE);
 	writel(XGMAC_TDPS, ioaddr + XGMAC_TX_EDMA_CTRL);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index e9c3c18b9fc1..0b1e571f70f0 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -189,6 +189,43 @@ int stmmac_set_clk_tx_rate(void *bsp_priv, struct clk *clk_tx_i,
 }
 EXPORT_SYMBOL_GPL(stmmac_set_clk_tx_rate);
 
+/**
+ * stmmac_axi_blen_to_mask() - convert a burst length array to reg value
+ * @regval: pointer to a u32 for the resulting register value
+ * @blen: pointer to an array of u32 containing the burst length values in bytes
+ * @len: the number of entries in the @blen array
+ */
+void stmmac_axi_blen_to_mask(u32 *regval, const u32 *blen, size_t len)
+{
+	size_t i;
+	u32 val;
+
+	for (val = i = 0; i < len; i++) {
+		u32 burst = blen[i];
+
+		/* Burst values of zero must be skipped. */
+		if (!burst)
+			continue;
+
+		/* The valid range for the burst length is 4 to 256 inclusive,
+		 * and it must be a power of two.
+		 */
+		if (burst < 4 || burst > 256 || !is_power_of_2(burst)) {
+			pr_err("stmmac: invalid burst length %u at index %zu\n",
+			       burst, i);
+			continue;
+		}
+
+		/* Since burst is a power of two, and the register field starts
+		 * with burst = 4, shift right by two bits so bit 0 of the field
+		 * corresponds with the minimum value.
+		 */
+		val |= burst >> 2;
+	}
+
+	u32p_replace_bits(regval, val, DMA_AXI_BLEN_MASK);
+}
+
 /**
  * stmmac_verify_args - verify the driver parameters.
  * Description: it checks the driver parameters and set a default in case of

From 6ff3310ca28298e363c78143b6a2f20312421f4e Mon Sep 17 00:00:00 2001
From: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Date: Wed, 19 Nov 2025 10:23:30 +0000
Subject: [PATCH 4/6] net: stmmac: move stmmac_axi_blen_to_mask() to
 stmmac_main.c

Move the call to stmmac_axi_blen_to_mask() out of the individual
MAC version drivers into the main code in stmmac_init_dma_engine(),
passing the resulting value through a new member, axi_blen_regval,
in the struct stmmac_axi structure.

There is now no need for stmmac_axi_blen_to_dma_mask() to use
u32p_replace_bits(), so use FIELD_PREP() instead.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vLfLW-0000000FMb1-0zKV@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c | 3 +--
 drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c    | 3 +--
 drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c  | 3 +--
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c   | 8 ++++++--
 include/linux/stmmac.h                              | 1 +
 5 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
index b6476a1bfeab..6d9b8fac3c6d 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
@@ -41,8 +41,7 @@ static void dwmac1000_dma_axi(void __iomem *ioaddr, struct stmmac_axi *axi)
 	 * set). Note that the UNDEF bit is readonly, and is the inverse of
 	 * Bus Mode bit 16.
 	 */
-	stmmac_axi_blen_to_mask(&value, axi->axi_blen,
-				ARRAY_SIZE(axi->axi_blen));
+	value = (value & ~DMA_AXI_BLEN_MASK) | axi->axi_blen_regval;
 
 	writel(value, ioaddr + DMA_AXI_BUS_MODE);
 }
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
index 90d03c7b29f4..7b513324cfb0 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
@@ -40,8 +40,7 @@ static void dwmac4_dma_axi(void __iomem *ioaddr, struct stmmac_axi *axi)
 	 * set). Note that the UNDEF bit is readonly, and is the inverse of
 	 * Bus Mode bit 16.
 	 */
-	stmmac_axi_blen_to_mask(&value, axi->axi_blen,
-				ARRAY_SIZE(axi->axi_blen));
+	value = (value & ~DMA_AXI_BLEN_MASK) | axi->axi_blen_regval;
 
 	writel(value, ioaddr + DMA_SYS_BUS_MODE);
 }
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
index 8a2cb6ca9588..cc1bdc0975d5 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
@@ -106,8 +106,7 @@ static void dwxgmac2_dma_axi(void __iomem *ioaddr, struct stmmac_axi *axi)
 	 * set). Note that the UNDEF bit is readonly, and is the inverse of
 	 * Bus Mode bit 16.
 	 */
-	stmmac_axi_blen_to_mask(&value, axi->axi_blen,
-				ARRAY_SIZE(axi->axi_blen));
+	value = (value & ~DMA_AXI_BLEN_MASK) | axi->axi_blen_regval;
 
 	writel(value, ioaddr + XGMAC_DMA_SYSBUS_MODE);
 	writel(XGMAC_TDPS, ioaddr + XGMAC_TX_EDMA_CTRL);
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 0b1e571f70f0..aac82ddfb8c0 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -223,7 +223,7 @@ void stmmac_axi_blen_to_mask(u32 *regval, const u32 *blen, size_t len)
 		val |= burst >> 2;
 	}
 
-	u32p_replace_bits(regval, val, DMA_AXI_BLEN_MASK);
+	*regval = FIELD_PREP(DMA_AXI_BLEN_MASK, val);
 }
 
 /**
@@ -3212,8 +3212,12 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 	/* DMA Configuration */
 	stmmac_dma_init(priv, priv->ioaddr, priv->plat->dma_cfg);
 
-	if (priv->plat->axi)
+	if (priv->plat->axi) {
+		/* Encode the AXI burst length to a register value */
+		stmmac_axi_blen_to_mask(&priv->plat->axi->axi_blen_regval,
+					priv->plat->axi->axi_blen, AXI_BLEN);
 		stmmac_axi(priv, priv->ioaddr, priv->plat->axi);
+	}
 
 	/* DMA CSR Channel configuration */
 	for (chan = 0; chan < dma_csr_ch; chan++) {
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index 673b068fdadf..d1a41fe0825f 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -113,6 +113,7 @@ struct stmmac_axi {
 	u32 axi_wr_osr_lmt;
 	u32 axi_rd_osr_lmt;
 	bool axi_kbbe;
+	u32 axi_blen_regval;
 	u32 axi_blen[AXI_BLEN];
 	bool axi_fb;
 	bool axi_mb;

From e676cc8561c86799f9e12f8cea550c226130821a Mon Sep 17 00:00:00 2001
From: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Date: Wed, 19 Nov 2025 10:23:35 +0000
Subject: [PATCH 5/6] net: stmmac: move stmmac_axi_blen_to_mask() to axi_blen
 init sites

Move stmmac_axi_blen_to_mask() to the axi->axi_blen array init sites
to prepare for the removal of axi_blen. For sites which initialise
axi->axi_blen with constant data, initialise axi->axi_blen_regval
using the DMA_AXI_BLENx constants.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vLfLb-0000000FMb7-1SgG@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c | 3 +++
 drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c       | 2 ++
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c       | 7 ++-----
 drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c        | 2 ++
 drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c   | 1 +
 5 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
index e6d5893c5905..bd06f26a27b4 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
@@ -88,6 +88,9 @@ static int dwc_eth_dwmac_config_dt(struct platform_device *pdev,
 		if (burst_map & (1 << bit_index))
 			plat_dat->axi->axi_blen[a_index++] = 4 << bit_index;
 
+	stmmac_axi_blen_to_mask(&plat_dat->axi->axi_blen_regval,
+				plat_dat->axi->axi_blen, a_index);
+
 	/* dwc-qos needs GMAC4, AAL, TSO and PMT */
 	plat_dat->core_type = DWMAC_CORE_GMAC4;
 	plat_dat->dma_cfg->aal = 1;
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
index 8938e7a59925..e94605d3d185 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
@@ -650,6 +650,8 @@ static int intel_mgbe_common_data(struct pci_dev *pdev,
 	plat->axi->axi_xit_frm = 0;
 	plat->axi->axi_wr_osr_lmt = 1;
 	plat->axi->axi_rd_osr_lmt = 1;
+	plat->axi->axi_blen_regval = DMA_AXI_BLEN4 | DMA_AXI_BLEN8 |
+				     DMA_AXI_BLEN16;
 	plat->axi->axi_blen[0] = 4;
 	plat->axi->axi_blen[1] = 8;
 	plat->axi->axi_blen[2] = 16;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index aac82ddfb8c0..b1aa236d8051 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -225,6 +225,7 @@ void stmmac_axi_blen_to_mask(u32 *regval, const u32 *blen, size_t len)
 
 	*regval = FIELD_PREP(DMA_AXI_BLEN_MASK, val);
 }
+EXPORT_SYMBOL_GPL(stmmac_axi_blen_to_mask);
 
 /**
  * stmmac_verify_args - verify the driver parameters.
@@ -3212,12 +3213,8 @@ static int stmmac_init_dma_engine(struct stmmac_priv *priv)
 	/* DMA Configuration */
 	stmmac_dma_init(priv, priv->ioaddr, priv->plat->dma_cfg);
 
-	if (priv->plat->axi) {
-		/* Encode the AXI burst length to a register value */
-		stmmac_axi_blen_to_mask(&priv->plat->axi->axi_blen_regval,
-					priv->plat->axi->axi_blen, AXI_BLEN);
+	if (priv->plat->axi)
 		stmmac_axi(priv, priv->ioaddr, priv->plat->axi);
-	}
 
 	/* DMA CSR Channel configuration */
 	for (chan = 0; chan < dma_csr_ch; chan++) {
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
index 2fd4660838bb..e1036150fae2 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
@@ -92,6 +92,8 @@ static int snps_gmac5_default_data(struct pci_dev *pdev,
 	plat->axi->axi_rd_osr_lmt = 31;
 
 	plat->axi->axi_fb = false;
+	plat->axi->axi_blen_regval = DMA_AXI_BLEN4 | DMA_AXI_BLEN8 |
+				     DMA_AXI_BLEN16 | DMA_AXI_BLEN32;
 	plat->axi->axi_blen[0] = 4;
 	plat->axi->axi_blen[1] = 8;
 	plat->axi->axi_blen[2] = 16;
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 9015b7f80d1b..656d4adedabe 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -118,6 +118,7 @@ static struct stmmac_axi *stmmac_axi_setup(struct platform_device *pdev)
 	if (of_property_read_u32(np, "snps,rd_osr_lmt", &axi->axi_rd_osr_lmt))
 		axi->axi_rd_osr_lmt = 1;
 	of_property_read_u32_array(np, "snps,blen", axi->axi_blen, AXI_BLEN);
+	stmmac_axi_blen_to_mask(&axi->axi_blen_regval, axi->axi_blen, AXI_BLEN);
 	of_node_put(np);
 
 	return axi;

From efd3c8cc52bb9583183ebb83c8c55b23bf97cb2f Mon Sep 17 00:00:00 2001
From: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Date: Wed, 19 Nov 2025 10:23:40 +0000
Subject: [PATCH 6/6] net: stmmac: remove axi_blen array

Remove the axi_blen array from struct stmmac_axi as we set this array,
and then immediately convert it ot the register value, never looking at
the array again. Thus, the array can be function local rather than part
of a run-time allocated long-lived struct.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/E1vLfLg-0000000FMbD-1vmh@rmk-PC.armlinux.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 .../net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c   | 11 ++---------
 drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c     |  3 ---
 drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c      |  4 ----
 drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c |  5 +++--
 include/linux/stmmac.h                                |  1 -
 5 files changed, 5 insertions(+), 19 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
index bd06f26a27b4..d043bad4a862 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
@@ -38,8 +38,6 @@ static int dwc_eth_dwmac_config_dt(struct platform_device *pdev,
 {
 	struct device *dev = &pdev->dev;
 	u32 burst_map = 0;
-	u32 bit_index = 0;
-	u32 a_index = 0;
 
 	if (!plat_dat->axi) {
 		plat_dat->axi = devm_kzalloc(&pdev->dev,
@@ -83,13 +81,8 @@ static int dwc_eth_dwmac_config_dt(struct platform_device *pdev,
 	}
 	device_property_read_u32(dev, "snps,burst-map", &burst_map);
 
-	/* converts burst-map bitmask to burst array */
-	for (bit_index = 0; bit_index < 7; bit_index++)
-		if (burst_map & (1 << bit_index))
-			plat_dat->axi->axi_blen[a_index++] = 4 << bit_index;
-
-	stmmac_axi_blen_to_mask(&plat_dat->axi->axi_blen_regval,
-				plat_dat->axi->axi_blen, a_index);
+	plat_dat->axi->axi_blen_regval = FIELD_PREP(DMA_AXI_BLEN_MASK,
+						    burst_map);
 
 	/* dwc-qos needs GMAC4, AAL, TSO and PMT */
 	plat_dat->core_type = DWMAC_CORE_GMAC4;
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
index e94605d3d185..aad1be1ec4c1 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
@@ -652,9 +652,6 @@ static int intel_mgbe_common_data(struct pci_dev *pdev,
 	plat->axi->axi_rd_osr_lmt = 1;
 	plat->axi->axi_blen_regval = DMA_AXI_BLEN4 | DMA_AXI_BLEN8 |
 				     DMA_AXI_BLEN16;
-	plat->axi->axi_blen[0] = 4;
-	plat->axi->axi_blen[1] = 8;
-	plat->axi->axi_blen[2] = 16;
 
 	plat->ptp_max_adj = plat->clk_ptp_rate;
 
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
index e1036150fae2..afb1c53ca6f8 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_pci.c
@@ -94,10 +94,6 @@ static int snps_gmac5_default_data(struct pci_dev *pdev,
 	plat->axi->axi_fb = false;
 	plat->axi->axi_blen_regval = DMA_AXI_BLEN4 | DMA_AXI_BLEN8 |
 				     DMA_AXI_BLEN16 | DMA_AXI_BLEN32;
-	plat->axi->axi_blen[0] = 4;
-	plat->axi->axi_blen[1] = 8;
-	plat->axi->axi_blen[2] = 16;
-	plat->axi->axi_blen[3] = 32;
 
 	return 0;
 }
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 656d4adedabe..8979a50b5507 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -95,6 +95,7 @@ static struct stmmac_axi *stmmac_axi_setup(struct platform_device *pdev)
 {
 	struct device_node *np;
 	struct stmmac_axi *axi;
+	u32 axi_blen[AXI_BLEN];
 
 	np = of_parse_phandle(pdev->dev.of_node, "snps,axi-config", 0);
 	if (!np)
@@ -117,8 +118,8 @@ static struct stmmac_axi *stmmac_axi_setup(struct platform_device *pdev)
 		axi->axi_wr_osr_lmt = 1;
 	if (of_property_read_u32(np, "snps,rd_osr_lmt", &axi->axi_rd_osr_lmt))
 		axi->axi_rd_osr_lmt = 1;
-	of_property_read_u32_array(np, "snps,blen", axi->axi_blen, AXI_BLEN);
-	stmmac_axi_blen_to_mask(&axi->axi_blen_regval, axi->axi_blen, AXI_BLEN);
+	of_property_read_u32_array(np, "snps,blen", axi_blen, AXI_BLEN);
+	stmmac_axi_blen_to_mask(&axi->axi_blen_regval, axi_blen, AXI_BLEN);
 	of_node_put(np);
 
 	return axi;
diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index d1a41fe0825f..f1054b9c2d8a 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -114,7 +114,6 @@ struct stmmac_axi {
 	u32 axi_rd_osr_lmt;
 	bool axi_kbbe;
 	u32 axi_blen_regval;
-	u32 axi_blen[AXI_BLEN];
 	bool axi_fb;
 	bool axi_mb;
 	bool axi_rb;