stmmac: add DMA support for GMAC 4.xx

DMA behavior is linked to descriptor management:

-descriptor mechanism (Tx for example, but it is exactly the same for RX):
-useful registers:
-DMA_CH#_TxDesc_Ring_Len: length of transmit descriptor ring
-DMA_CH#_TxDesc_List_Address: start address of the ring
	-DMA_CH#_TxDesc_Tail_Pointer: address of the last
					      descriptor to send + 1.
	-DMA_CH#_TxDesc_Current_App_TxDesc: address of the current
						    descriptor

-The descriptor Tail Pointer register contains the pointer to the
 descriptor address (N). The base address and the current
 descriptor decide the address of the current descriptor that the
 DMA can process. The descriptors up to one location less than the
 one indicated by the descriptor tail pointer (N-1) are owned by
 the DMA. The DMA continues to process the descriptors until the
 following condition occurs:
 "current descriptor pointer == Descriptor Tail pointer"

Then the DMA goes into suspend mode. The application must perform
a write to descriptor tail pointer register and update the tail
pointer to have the following condition and to start a new transfer:
"current descriptor pointer < Descriptor tail pointer"

The DMA automatically wraps around the base address when the end
of ring is reached.

Up to 8 DMA could be use but currently we only use one (channel0)

Signed-off-by: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 354 insertions, 0 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
new file mode 100644
index 000000000000..116151cd6a95
--- /dev/null
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c
@@ -0,0 +1,354 @@
+/*
+ * This is the driver for the GMAC on-chip Ethernet controller for ST SoCs.
+ * DWC Ether MAC version 4.xx  has been used for  developing this code.
+ *
+ * This contains the functions to handle the dma.
+ *
+ * Copyright (C) 2015  STMicroelectronics Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * Author: Alexandre Torgue <alexandre.torgue@st.com>
+ */
+
+#include <linux/io.h>
+#include "dwmac4.h"
+#include "dwmac4_dma.h"
+
+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");
+
+	if (axi->axi_lpi_en)
+		value |= DMA_AXI_EN_LPI;
+	if (axi->axi_xit_frm)
+		value |= DMA_AXI_LPI_XIT_FRM;
+
+	value |= (axi->axi_wr_osr_lmt & DMA_AXI_OSR_MAX) <<
+		 DMA_AXI_WR_OSR_LMT_SHIFT;
+
+	value |= (axi->axi_rd_osr_lmt & DMA_AXI_OSR_MAX) <<
+		 DMA_AXI_RD_OSR_LMT_SHIFT;
+
+	/* Depending on the UNDEF bit the Master AXI will perform any burst
+	 * length according to the BLEN programmed (by default all BLEN are
+	 * set).
+	 */
+	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;
+		}
+	}
+
+	writel(value, ioaddr + DMA_SYS_BUS_MODE);
+}
+
+static void dwmac4_dma_init_channel(void __iomem *ioaddr, int pbl,
+				    u32 dma_tx_phy, u32 dma_rx_phy,
+				    u32 channel)
+{
+	u32 value;
+
+	/* set PBL for each channels. Currently we affect same configuration
+	 * on each channel
+	 */
+	value = readl(ioaddr + DMA_CHAN_CONTROL(channel));
+	value = value | DMA_BUS_MODE_PBL;
+	writel(value, ioaddr + DMA_CHAN_CONTROL(channel));
+
+	value = readl(ioaddr + DMA_CHAN_TX_CONTROL(channel));
+	value = value | (pbl << 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);
+	writel(value, ioaddr + DMA_CHAN_RX_CONTROL(channel));
+
+	/* Mask interrupts by writing to CSR7 */
+	writel(DMA_CHAN_INTR_DEFAULT_MASK, ioaddr + DMA_CHAN_INTR_ENA(channel));
+
+	writel(dma_tx_phy, ioaddr + DMA_CHAN_TX_BASE_ADDR(channel));
+	writel(dma_rx_phy, ioaddr + DMA_CHAN_RX_BASE_ADDR(channel));
+}
+
+static void dwmac4_dma_init(void __iomem *ioaddr, int pbl, int fb, int mb,
+			    int aal, u32 dma_tx, u32 dma_rx, int atds)
+{
+	u32 value = readl(ioaddr + DMA_SYS_BUS_MODE);
+	int i;
+
+	/* Set the Fixed burst mode */
+	if (fb)
+		value |= DMA_SYS_BUS_FB;
+
+	/* Mixed Burst has no effect when fb is set */
+	if (mb)
+		value |= DMA_SYS_BUS_MB;
+
+	if (aal)
+		value |= DMA_SYS_BUS_AAL;
+
+	writel(value, ioaddr + DMA_SYS_BUS_MODE);
+
+	for (i = 0; i < DMA_CHANNEL_NB_MAX; i++)
+		dwmac4_dma_init_channel(ioaddr, pbl, dma_tx, dma_rx, i);
+}
+
+static void _dwmac4_dump_dma_regs(void __iomem *ioaddr, u32 channel)
+{
+	pr_debug(" Channel %d\n", channel);
+	pr_debug("\tDMA_CHAN_CONTROL, offset: 0x%x, val: 0x%x\n", 0,
+		 readl(ioaddr + DMA_CHAN_CONTROL(channel)));
+	pr_debug("\tDMA_CHAN_TX_CONTROL, offset: 0x%x, val: 0x%x\n", 0x4,
+		 readl(ioaddr + DMA_CHAN_TX_CONTROL(channel)));
+	pr_debug("\tDMA_CHAN_RX_CONTROL, offset: 0x%x, val: 0x%x\n", 0x8,
+		 readl(ioaddr + DMA_CHAN_RX_CONTROL(channel)));
+	pr_debug("\tDMA_CHAN_TX_BASE_ADDR, offset: 0x%x, val: 0x%x\n", 0x14,
+		 readl(ioaddr + DMA_CHAN_TX_BASE_ADDR(channel)));
+	pr_debug("\tDMA_CHAN_RX_BASE_ADDR, offset: 0x%x, val: 0x%x\n", 0x1c,
+		 readl(ioaddr + DMA_CHAN_RX_BASE_ADDR(channel)));
+	pr_debug("\tDMA_CHAN_TX_END_ADDR, offset: 0x%x, val: 0x%x\n", 0x20,
+		 readl(ioaddr + DMA_CHAN_TX_END_ADDR(channel)));
+	pr_debug("\tDMA_CHAN_RX_END_ADDR, offset: 0x%x, val: 0x%x\n", 0x28,
+		 readl(ioaddr + DMA_CHAN_RX_END_ADDR(channel)));
+	pr_debug("\tDMA_CHAN_TX_RING_LEN, offset: 0x%x, val: 0x%x\n", 0x2c,
+		 readl(ioaddr + DMA_CHAN_TX_RING_LEN(channel)));
+	pr_debug("\tDMA_CHAN_RX_RING_LEN, offset: 0x%x, val: 0x%x\n", 0x30,
+		 readl(ioaddr + DMA_CHAN_RX_RING_LEN(channel)));
+	pr_debug("\tDMA_CHAN_INTR_ENA, offset: 0x%x, val: 0x%x\n", 0x34,
+		 readl(ioaddr + DMA_CHAN_INTR_ENA(channel)));
+	pr_debug("\tDMA_CHAN_RX_WATCHDOG, offset: 0x%x, val: 0x%x\n", 0x38,
+		 readl(ioaddr + DMA_CHAN_RX_WATCHDOG(channel)));
+	pr_debug("\tDMA_CHAN_SLOT_CTRL_STATUS, offset: 0x%x, val: 0x%x\n", 0x3c,
+		 readl(ioaddr + DMA_CHAN_SLOT_CTRL_STATUS(channel)));
+	pr_debug("\tDMA_CHAN_CUR_TX_DESC, offset: 0x%x, val: 0x%x\n", 0x44,
+		 readl(ioaddr + DMA_CHAN_CUR_TX_DESC(channel)));
+	pr_debug("\tDMA_CHAN_CUR_RX_DESC, offset: 0x%x, val: 0x%x\n", 0x4c,
+		 readl(ioaddr + DMA_CHAN_CUR_RX_DESC(channel)));
+	pr_debug("\tDMA_CHAN_CUR_TX_BUF_ADDR, offset: 0x%x, val: 0x%x\n", 0x54,
+		 readl(ioaddr + DMA_CHAN_CUR_TX_BUF_ADDR(channel)));
+	pr_debug("\tDMA_CHAN_CUR_RX_BUF_ADDR, offset: 0x%x, val: 0x%x\n", 0x5c,
+		 readl(ioaddr + DMA_CHAN_CUR_RX_BUF_ADDR(channel)));
+	pr_debug("\tDMA_CHAN_STATUS, offset: 0x%x, val: 0x%x\n", 0x60,
+		 readl(ioaddr + DMA_CHAN_STATUS(channel)));
+}
+
+static void dwmac4_dump_dma_regs(void __iomem *ioaddr)
+{
+	int i;
+
+	pr_debug(" GMAC4 DMA registers\n");
+
+	for (i = 0; i < DMA_CHANNEL_NB_MAX; i++)
+		_dwmac4_dump_dma_regs(ioaddr, i);
+}
+
+static void dwmac4_rx_watchdog(void __iomem *ioaddr, u32 riwt)
+{
+	int i;
+
+	for (i = 0; i < DMA_CHANNEL_NB_MAX; i++)
+		writel(riwt, ioaddr + DMA_CHAN_RX_WATCHDOG(i));
+}
+
+static void dwmac4_dma_chan_op_mode(void __iomem *ioaddr, int txmode,
+				    int rxmode, u32 channel)
+{
+	u32 mtl_tx_op, mtl_rx_op, mtl_rx_int;
+
+	/* Following code only done for channel 0, other channels not yet
+	 * supported.
+	 */
+	mtl_tx_op = readl(ioaddr + MTL_CHAN_TX_OP_MODE(channel));
+
+	if (txmode == SF_DMA_MODE) {
+		pr_debug("GMAC: enable TX store and forward mode\n");
+		/* Transmit COE type 2 cannot be done in cut-through mode. */
+		mtl_tx_op |= MTL_OP_MODE_TSF;
+	} else {
+		pr_debug("GMAC: disabling TX SF (threshold %d)\n", txmode);
+		mtl_tx_op &= ~MTL_OP_MODE_TSF;
+		mtl_tx_op &= MTL_OP_MODE_TTC_MASK;
+		/* Set the transmit threshold */
+		if (txmode <= 32)
+			mtl_tx_op |= MTL_OP_MODE_TTC_32;
+		else if (txmode <= 64)
+			mtl_tx_op |= MTL_OP_MODE_TTC_64;
+		else if (txmode <= 96)
+			mtl_tx_op |= MTL_OP_MODE_TTC_96;
+		else if (txmode <= 128)
+			mtl_tx_op |= MTL_OP_MODE_TTC_128;
+		else if (txmode <= 192)
+			mtl_tx_op |= MTL_OP_MODE_TTC_192;
+		else if (txmode <= 256)
+			mtl_tx_op |= MTL_OP_MODE_TTC_256;
+		else if (txmode <= 384)
+			mtl_tx_op |= MTL_OP_MODE_TTC_384;
+		else
+			mtl_tx_op |= MTL_OP_MODE_TTC_512;
+	}
+
+	writel(mtl_tx_op, ioaddr +  MTL_CHAN_TX_OP_MODE(channel));
+
+	mtl_rx_op = readl(ioaddr + MTL_CHAN_RX_OP_MODE(channel));
+
+	if (rxmode == SF_DMA_MODE) {
+		pr_debug("GMAC: enable RX store and forward mode\n");
+		mtl_rx_op |= MTL_OP_MODE_RSF;
+	} else {
+		pr_debug("GMAC: disable RX SF mode (threshold %d)\n", rxmode);
+		mtl_rx_op &= ~MTL_OP_MODE_RSF;
+		mtl_rx_op &= MTL_OP_MODE_RTC_MASK;
+		if (rxmode <= 32)
+			mtl_rx_op |= MTL_OP_MODE_RTC_32;
+		else if (rxmode <= 64)
+			mtl_rx_op |= MTL_OP_MODE_RTC_64;
+		else if (rxmode <= 96)
+			mtl_rx_op |= MTL_OP_MODE_RTC_96;
+		else
+			mtl_rx_op |= MTL_OP_MODE_RTC_128;
+	}
+
+	writel(mtl_rx_op, ioaddr + MTL_CHAN_RX_OP_MODE(channel));
+
+	/* Enable MTL RX overflow */
+	mtl_rx_int = readl(ioaddr + MTL_CHAN_INT_CTRL(channel));
+	writel(mtl_rx_int | MTL_RX_OVERFLOW_INT_EN,
+	       ioaddr + MTL_CHAN_INT_CTRL(channel));
+}
+
+static void dwmac4_dma_operation_mode(void __iomem *ioaddr, int txmode,
+				      int rxmode, int rxfifosz)
+{
+	/* Only Channel 0 is actually configured and used */
+	dwmac4_dma_chan_op_mode(ioaddr, txmode, rxmode, 0);
+}
+
+static void dwmac4_get_hw_feature(void __iomem *ioaddr,
+				  struct dma_features *dma_cap)
+{
+	u32 hw_cap = readl(ioaddr + GMAC_HW_FEATURE0);
+
+	/*  MAC HW feature0 */
+	dma_cap->mbps_10_100 = (hw_cap & GMAC_HW_FEAT_MIISEL);
+	dma_cap->mbps_1000 = (hw_cap & GMAC_HW_FEAT_GMIISEL) >> 1;
+	dma_cap->half_duplex = (hw_cap & GMAC_HW_FEAT_HDSEL) >> 2;
+	dma_cap->hash_filter = (hw_cap & GMAC_HW_FEAT_VLHASH) >> 4;
+	dma_cap->multi_addr = (hw_cap & GMAC_HW_FEAT_ADDMAC) >> 18;
+	dma_cap->pcs = (hw_cap & GMAC_HW_FEAT_PCSSEL) >> 3;
+	dma_cap->sma_mdio = (hw_cap & GMAC_HW_FEAT_SMASEL) >> 5;
+	dma_cap->pmt_remote_wake_up = (hw_cap & GMAC_HW_FEAT_RWKSEL) >> 6;
+	dma_cap->pmt_magic_frame = (hw_cap & GMAC_HW_FEAT_MGKSEL) >> 7;
+	/* MMC */
+	dma_cap->rmon = (hw_cap & GMAC_HW_FEAT_MMCSEL) >> 8;
+	/* IEEE 1588-2008 */
+	dma_cap->atime_stamp = (hw_cap & GMAC_HW_FEAT_TSSEL) >> 12;
+	/* 802.3az - Energy-Efficient Ethernet (EEE) */
+	dma_cap->eee = (hw_cap & GMAC_HW_FEAT_EEESEL) >> 13;
+	/* TX and RX csum */
+	dma_cap->tx_coe = (hw_cap & GMAC_HW_FEAT_TXCOSEL) >> 14;
+	dma_cap->rx_coe =  (hw_cap & GMAC_HW_FEAT_RXCOESEL) >> 16;
+
+	/* MAC HW feature1 */
+	hw_cap = readl(ioaddr + GMAC_HW_FEATURE1);
+	dma_cap->av = (hw_cap & GMAC_HW_FEAT_AVSEL) >> 20;
+	dma_cap->tsoen = (hw_cap & GMAC_HW_TSOEN) >> 18;
+	/* MAC HW feature2 */
+	hw_cap = readl(ioaddr + GMAC_HW_FEATURE2);
+	/* TX and RX number of channels */
+	dma_cap->number_rx_channel =
+		((hw_cap & GMAC_HW_FEAT_RXCHCNT) >> 12) + 1;
+	dma_cap->number_tx_channel =
+		((hw_cap & GMAC_HW_FEAT_TXCHCNT) >> 18) + 1;
+
+	/* IEEE 1588-2002 */
+	dma_cap->time_stamp = 0;
+}
+
+/* Enable/disable TSO feature and set MSS */
+static void dwmac4_enable_tso(void __iomem *ioaddr, bool en, u32 chan)
+{
+	u32 value;
+
+	if (en) {
+		/* enable TSO */
+		value = readl(ioaddr + DMA_CHAN_TX_CONTROL(chan));
+		writel(value | DMA_CONTROL_TSE,
+		       ioaddr + DMA_CHAN_TX_CONTROL(chan));
+	} else {
+		/* enable TSO */
+		value = readl(ioaddr + DMA_CHAN_TX_CONTROL(chan));
+		writel(value & ~DMA_CONTROL_TSE,
+		       ioaddr + DMA_CHAN_TX_CONTROL(chan));
+	}
+}
+
+const struct stmmac_dma_ops dwmac4_dma_ops = {
+	.reset = dwmac4_dma_reset,
+	.init = dwmac4_dma_init,
+	.axi = dwmac4_dma_axi,
+	.dump_regs = dwmac4_dump_dma_regs,
+	.dma_mode = dwmac4_dma_operation_mode,
+	.enable_dma_irq = dwmac4_enable_dma_irq,
+	.disable_dma_irq = dwmac4_disable_dma_irq,
+	.start_tx = dwmac4_dma_start_tx,
+	.stop_tx = dwmac4_dma_stop_tx,
+	.start_rx = dwmac4_dma_start_rx,
+	.stop_rx = dwmac4_dma_stop_rx,
+	.dma_interrupt = dwmac4_dma_interrupt,
+	.get_hw_feature = dwmac4_get_hw_feature,
+	.rx_watchdog = dwmac4_rx_watchdog,
+	.set_rx_ring_len = dwmac4_set_rx_ring_len,
+	.set_tx_ring_len = dwmac4_set_tx_ring_len,
+	.set_rx_tail_ptr = dwmac4_set_rx_tail_ptr,
+	.set_tx_tail_ptr = dwmac4_set_tx_tail_ptr,
+	.enable_tso = dwmac4_enable_tso,
+};
+
+const struct stmmac_dma_ops dwmac410_dma_ops = {
+	.reset = dwmac4_dma_reset,
+	.init = dwmac4_dma_init,
+	.axi = dwmac4_dma_axi,
+	.dump_regs = dwmac4_dump_dma_regs,
+	.dma_mode = dwmac4_dma_operation_mode,
+	.enable_dma_irq = dwmac410_enable_dma_irq,
+	.disable_dma_irq = dwmac4_disable_dma_irq,
+	.start_tx = dwmac4_dma_start_tx,
+	.stop_tx = dwmac4_dma_stop_tx,
+	.start_rx = dwmac4_dma_start_rx,
+	.stop_rx = dwmac4_dma_stop_rx,
+	.dma_interrupt = dwmac4_dma_interrupt,
+	.get_hw_feature = dwmac4_get_hw_feature,
+	.rx_watchdog = dwmac4_rx_watchdog,
+	.set_rx_ring_len = dwmac4_set_rx_ring_len,
+	.set_tx_ring_len = dwmac4_set_tx_ring_len,
+	.set_rx_tail_ptr = dwmac4_set_rx_tail_ptr,
+	.set_tx_tail_ptr = dwmac4_set_tx_tail_ptr,
+	.enable_tso = dwmac4_enable_tso,
+};