net: stmmac: add support for independent DMA pbl for tx/rx

GMAC and newer supports independent programmable burst lengths for
DMA tx/rx. Add new optional devicetree properties representing this.

To be backwards compatible, snps,pbl will still be valid, but
snps,txpbl/snps,rxpbl will override the value in snps,pbl if set.

If the IP is synthesized to use the AXI interface, there is a register
and a matching DT property inside the optional stmmac-axi-config DT node
for controlling burst lengths, named snps,blen.
However, using this register, it is not possible to control tx and rx
independently. Also, this register is not available if the IP was
synthesized with, e.g., the AHB interface.

Signed-off-by: Niklas Cassel <niklas.cassel@axis.com>
Acked-by: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 15 insertions, 11 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
index 318ae9f..99b8040 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac1000_dma.c
@@ -89,20 +89,20 @@ static void dwmac1000_dma_init(void __iomem *ioaddr,
 			       u32 dma_tx, u32 dma_rx, int atds)
 {
 	u32 value = readl(ioaddr + DMA_BUS_MODE);
+	int txpbl = dma_cfg->txpbl ?: dma_cfg->pbl;
+	int rxpbl = dma_cfg->rxpbl ?: dma_cfg->pbl;
 
 	/*
 	 * Set the DMA PBL (Programmable Burst Length) mode.
 	 *
 	 * Note: before stmmac core 3.50 this mode bit was 4xPBL, and
 	 * post 3.5 mode bit acts as 8*PBL.
-	 *
-	 * This configuration doesn't take care about the Separate PBL
-	 * so only the bits: 13-8 are programmed with the PBL passed from the
-	 * platform.
 	 */
 	value |= DMA_BUS_MODE_MAXPBL;
-	value &= ~DMA_BUS_MODE_PBL_MASK;
-	value |= (dma_cfg->pbl << DMA_BUS_MODE_PBL_SHIFT);
+	value |= DMA_BUS_MODE_USP;
+	value &= ~(DMA_BUS_MODE_PBL_MASK | DMA_BUS_MODE_RPBL_MASK);
+	value |= (txpbl << DMA_BUS_MODE_PBL_SHIFT);
+	value |= (rxpbl << DMA_BUS_MODE_RPBL_SHIFT);
 
 	/* Set the Fixed burst mode */
 	if (dma_cfg->fixed_burst)
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
index 7d82a34..2c3b209 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
@@ -71,11 +71,14 @@ static void dwmac4_dma_axi(void __iomem *ioaddr, struct stmmac_axi *axi)
 	writel(value, ioaddr + DMA_SYS_BUS_MODE);
 }
 
-static void dwmac4_dma_init_channel(void __iomem *ioaddr, int pbl,
+static void dwmac4_dma_init_channel(void __iomem *ioaddr,
+				    struct stmmac_dma_cfg *dma_cfg,
 				    u32 dma_tx_phy, u32 dma_rx_phy,
 				    u32 channel)
 {
 	u32 value;
+	int txpbl = dma_cfg->txpbl ?: dma_cfg->pbl;
+	int rxpbl = dma_cfg->rxpbl ?: dma_cfg->pbl;
 
 	/* set PBL for each channels. Currently we affect same configuration
 	 * on each channel
@@ -85,11 +88,11 @@ static void dwmac4_dma_init_channel(void __iomem *ioaddr, int pbl,
 	writel(value, ioaddr + DMA_CHAN_CONTROL(channel));
 
 	value = readl(ioaddr + DMA_CHAN_TX_CONTROL(channel));
-	value = value | (pbl << DMA_BUS_MODE_PBL_SHIFT);
+	value = value | (txpbl << DMA_BUS_MODE_PBL_SHIFT);
 	writel(value, ioaddr + DMA_CHAN_TX_CONTROL(channel));
 
 	value = readl(ioaddr + DMA_CHAN_RX_CONTROL(channel));
-	value = value | (pbl << DMA_BUS_MODE_RPBL_SHIFT);
+	value = value | (rxpbl << DMA_BUS_MODE_RPBL_SHIFT);
 	writel(value, ioaddr + DMA_CHAN_RX_CONTROL(channel));
 
 	/* Mask interrupts by writing to CSR7 */
@@ -120,8 +123,7 @@ static void dwmac4_dma_init(void __iomem *ioaddr,
 	writel(value, ioaddr + DMA_SYS_BUS_MODE);
 
 	for (i = 0; i < DMA_CHANNEL_NB_MAX; i++)
-		dwmac4_dma_init_channel(ioaddr, dma_cfg->pbl,
-					dma_tx, dma_rx, i);
+		dwmac4_dma_init_channel(ioaddr, dma_cfg, dma_tx, dma_rx, i);
 }
 
 static void _dwmac4_dump_dma_regs(void __iomem *ioaddr, u32 channel)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 81800f2..96afe05 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -315,6 +315,8 @@ stmmac_probe_config_dt(struct platform_device *pdev, const char **mac)
 	of_property_read_u32(np, "snps,pbl", &dma_cfg->pbl);
 	if (!dma_cfg->pbl)
 		dma_cfg->pbl = DEFAULT_DMA_PBL;
+	of_property_read_u32(np, "snps,txpbl", &dma_cfg->txpbl);
+	of_property_read_u32(np, "snps,rxpbl", &dma_cfg->rxpbl);
 
 	dma_cfg->aal = of_property_read_bool(np, "snps,aal");
 	dma_cfg->fixed_burst = of_property_read_bool(np, "snps,fixed-burst");