[PATCH net-next 3/6] net: stmmac: provide common stmmac_axi_blen_to_mask()

["Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>]

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>
---
 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 aac8188248ff..e5ed61154557 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
-- 
2.47.3