stmmac: add descriptors function for GMAC 4.xx

One of main changes of GMAC 4.xx IP is descriptors management.
-descriptors are only used in ring mode.
-A descriptor is composed of 4 32bits registers (no more extended
 descriptors)
-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.

-New features are available on IP:
-TSO (TCP Segmentation Offload) for TX only
-Split header: to have header and payload in 2 different buffers

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, 396 insertions, 0 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
new file mode 100644
index 000000000000..d4952c7a836d
--- /dev/null
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
@@ -0,0 +1,396 @@
+/*
+ * This contains the functions to handle the descriptors for DesignWare databook
+ * 4.xx.
+ *
+ * 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/stmmac.h>
+#include "common.h"
+#include "dwmac4_descs.h"
+
+static int dwmac4_wrback_get_tx_status(void *data, struct stmmac_extra_stats *x,
+				       struct dma_desc *p,
+				       void __iomem *ioaddr)
+{
+	struct net_device_stats *stats = (struct net_device_stats *)data;
+	unsigned int tdes3;
+	int ret = tx_done;
+
+	tdes3 = p->des3;
+
+	/* Get tx owner first */
+	if (unlikely(tdes3 & TDES3_OWN))
+		return tx_dma_own;
+
+	/* Verify tx error by looking at the last segment. */
+	if (likely(!(tdes3 & TDES3_LAST_DESCRIPTOR)))
+		return tx_not_ls;
+
+	if (unlikely(tdes3 & TDES3_ERROR_SUMMARY)) {
+		if (unlikely(tdes3 & TDES3_JABBER_TIMEOUT))
+			x->tx_jabber++;
+		if (unlikely(tdes3 & TDES3_PACKET_FLUSHED))
+			x->tx_frame_flushed++;
+		if (unlikely(tdes3 & TDES3_LOSS_CARRIER)) {
+			x->tx_losscarrier++;
+			stats->tx_carrier_errors++;
+		}
+		if (unlikely(tdes3 & TDES3_NO_CARRIER)) {
+			x->tx_carrier++;
+			stats->tx_carrier_errors++;
+		}
+		if (unlikely((tdes3 & TDES3_LATE_COLLISION) ||
+			     (tdes3 & TDES3_EXCESSIVE_COLLISION)))
+			stats->collisions +=
+			    (tdes3 & TDES3_COLLISION_COUNT_MASK)
+			    >> TDES3_COLLISION_COUNT_SHIFT;
+
+		if (unlikely(tdes3 & TDES3_EXCESSIVE_DEFERRAL))
+			x->tx_deferred++;
+
+		if (unlikely(tdes3 & TDES3_UNDERFLOW_ERROR))
+			x->tx_underflow++;
+
+		if (unlikely(tdes3 & TDES3_IP_HDR_ERROR))
+			x->tx_ip_header_error++;
+
+		if (unlikely(tdes3 & TDES3_PAYLOAD_ERROR))
+			x->tx_payload_error++;
+
+		ret = tx_err;
+	}
+
+	if (unlikely(tdes3 & TDES3_DEFERRED))
+		x->tx_deferred++;
+
+	return ret;
+}
+
+static int dwmac4_wrback_get_rx_status(void *data, struct stmmac_extra_stats *x,
+				       struct dma_desc *p)
+{
+	struct net_device_stats *stats = (struct net_device_stats *)data;
+	unsigned int rdes1 = p->des1;
+	unsigned int rdes2 = p->des2;
+	unsigned int rdes3 = p->des3;
+	int message_type;
+	int ret = good_frame;
+
+	if (unlikely(rdes3 & RDES3_OWN))
+		return dma_own;
+
+	/* Verify rx error by looking at the last segment. */
+	if (likely(!(rdes3 & RDES3_LAST_DESCRIPTOR)))
+		return discard_frame;
+
+	if (unlikely(rdes3 & RDES3_ERROR_SUMMARY)) {
+		if (unlikely(rdes3 & RDES3_GIANT_PACKET))
+			stats->rx_length_errors++;
+		if (unlikely(rdes3 & RDES3_OVERFLOW_ERROR))
+			x->rx_gmac_overflow++;
+
+		if (unlikely(rdes3 & RDES3_RECEIVE_WATCHDOG))
+			x->rx_watchdog++;
+
+		if (unlikely(rdes3 & RDES3_RECEIVE_ERROR))
+			x->rx_mii++;
+
+		if (unlikely(rdes3 & RDES3_CRC_ERROR)) {
+			x->rx_crc++;
+			stats->rx_crc_errors++;
+		}
+
+		if (unlikely(rdes3 & RDES3_DRIBBLE_ERROR))
+			x->dribbling_bit++;
+
+		ret = discard_frame;
+	}
+
+	message_type = (rdes1 & ERDES4_MSG_TYPE_MASK) >> 8;
+
+	if (rdes1 & RDES1_IP_HDR_ERROR)
+		x->ip_hdr_err++;
+	if (rdes1 & RDES1_IP_CSUM_BYPASSED)
+		x->ip_csum_bypassed++;
+	if (rdes1 & RDES1_IPV4_HEADER)
+		x->ipv4_pkt_rcvd++;
+	if (rdes1 & RDES1_IPV6_HEADER)
+		x->ipv6_pkt_rcvd++;
+	if (message_type == RDES_EXT_SYNC)
+		x->rx_msg_type_sync++;
+	else if (message_type == RDES_EXT_FOLLOW_UP)
+		x->rx_msg_type_follow_up++;
+	else if (message_type == RDES_EXT_DELAY_REQ)
+		x->rx_msg_type_delay_req++;
+	else if (message_type == RDES_EXT_DELAY_RESP)
+		x->rx_msg_type_delay_resp++;
+	else if (message_type == RDES_EXT_PDELAY_REQ)
+		x->rx_msg_type_pdelay_req++;
+	else if (message_type == RDES_EXT_PDELAY_RESP)
+		x->rx_msg_type_pdelay_resp++;
+	else if (message_type == RDES_EXT_PDELAY_FOLLOW_UP)
+		x->rx_msg_type_pdelay_follow_up++;
+	else
+		x->rx_msg_type_ext_no_ptp++;
+
+	if (rdes1 & RDES1_PTP_PACKET_TYPE)
+		x->ptp_frame_type++;
+	if (rdes1 & RDES1_PTP_VER)
+		x->ptp_ver++;
+	if (rdes1 & RDES1_TIMESTAMP_DROPPED)
+		x->timestamp_dropped++;
+
+	if (unlikely(rdes2 & RDES2_SA_FILTER_FAIL)) {
+		x->sa_rx_filter_fail++;
+		ret = discard_frame;
+	}
+	if (unlikely(rdes2 & RDES2_DA_FILTER_FAIL)) {
+		x->da_rx_filter_fail++;
+		ret = discard_frame;
+	}
+
+	if (rdes2 & RDES2_L3_FILTER_MATCH)
+		x->l3_filter_match++;
+	if (rdes2 & RDES2_L4_FILTER_MATCH)
+		x->l4_filter_match++;
+	if ((rdes2 & RDES2_L3_L4_FILT_NB_MATCH_MASK)
+	    >> RDES2_L3_L4_FILT_NB_MATCH_SHIFT)
+		x->l3_l4_filter_no_match++;
+
+	return ret;
+}
+
+static int dwmac4_rd_get_tx_len(struct dma_desc *p)
+{
+	return (p->des2 & TDES2_BUFFER1_SIZE_MASK);
+}
+
+static int dwmac4_get_tx_owner(struct dma_desc *p)
+{
+	return (p->des3 & TDES3_OWN) >> TDES3_OWN_SHIFT;
+}
+
+static void dwmac4_set_tx_owner(struct dma_desc *p)
+{
+	p->des3 |= TDES3_OWN;
+}
+
+static void dwmac4_set_rx_owner(struct dma_desc *p)
+{
+	p->des3 |= RDES3_OWN;
+}
+
+static int dwmac4_get_tx_ls(struct dma_desc *p)
+{
+	return (p->des3 & TDES3_LAST_DESCRIPTOR) >> TDES3_LAST_DESCRIPTOR_SHIFT;
+}
+
+static int dwmac4_wrback_get_rx_frame_len(struct dma_desc *p, int rx_coe)
+{
+	return (p->des3 & RDES3_PACKET_SIZE_MASK);
+}
+
+static void dwmac4_rd_enable_tx_timestamp(struct dma_desc *p)
+{
+	p->des2 |= TDES2_TIMESTAMP_ENABLE;
+}
+
+static int dwmac4_wrback_get_tx_timestamp_status(struct dma_desc *p)
+{
+	return (p->des3 & TDES3_TIMESTAMP_STATUS)
+		>> TDES3_TIMESTAMP_STATUS_SHIFT;
+}
+
+/*  NOTE: For RX CTX bit has to be checked before
+ *  HAVE a specific function for TX and another one for RX
+ */
+static u64 dwmac4_wrback_get_timestamp(void *desc, u32 ats)
+{
+	struct dma_desc *p = (struct dma_desc *)desc;
+	u64 ns;
+
+	ns = p->des0;
+	/* convert high/sec time stamp value to nanosecond */
+	ns += p->des1 * 1000000000ULL;
+
+	return ns;
+}
+
+static int dwmac4_context_get_rx_timestamp_status(void *desc, u32 ats)
+{
+	struct dma_desc *p = (struct dma_desc *)desc;
+
+	return (p->des1 & RDES1_TIMESTAMP_AVAILABLE)
+		>> RDES1_TIMESTAMP_AVAILABLE_SHIFT;
+}
+
+static void dwmac4_rd_init_rx_desc(struct dma_desc *p, int disable_rx_ic,
+				   int mode, int end)
+{
+	p->des3 = RDES3_OWN | RDES3_BUFFER1_VALID_ADDR;
+
+	if (!disable_rx_ic)
+		p->des3 |= RDES3_INT_ON_COMPLETION_EN;
+}
+
+static void dwmac4_rd_init_tx_desc(struct dma_desc *p, int mode, int end)
+{
+	p->des0 = 0;
+	p->des1 = 0;
+	p->des2 = 0;
+	p->des3 = 0;
+}
+
+static void dwmac4_rd_prepare_tx_desc(struct dma_desc *p, int is_fs, int len,
+				      bool csum_flag, int mode, bool tx_own,
+				      bool ls)
+{
+	unsigned int tdes3 = p->des3;
+
+	if (unlikely(len > BUF_SIZE_16KiB)) {
+		p->des2 |= (((len - BUF_SIZE_16KiB) <<
+			     TDES2_BUFFER2_SIZE_MASK_SHIFT)
+			    & TDES2_BUFFER2_SIZE_MASK)
+			    | (BUF_SIZE_16KiB & TDES2_BUFFER1_SIZE_MASK);
+	} else {
+		p->des2 |= (len & TDES2_BUFFER1_SIZE_MASK);
+	}
+
+	if (is_fs)
+		tdes3 |= TDES3_FIRST_DESCRIPTOR;
+	else
+		tdes3 &= ~TDES3_FIRST_DESCRIPTOR;
+
+	if (likely(csum_flag))
+		tdes3 |= (TX_CIC_FULL << TDES3_CHECKSUM_INSERTION_SHIFT);
+	else
+		tdes3 &= ~(TX_CIC_FULL << TDES3_CHECKSUM_INSERTION_SHIFT);
+
+	if (ls)
+		tdes3 |= TDES3_LAST_DESCRIPTOR;
+	else
+		tdes3 &= ~TDES3_LAST_DESCRIPTOR;
+
+	/* Finally set the OWN bit. Later the DMA will start! */
+	if (tx_own)
+		tdes3 |= TDES3_OWN;
+
+	if (is_fs & tx_own)
+		/* When the own bit, for the first frame, has to be set, all
+		 * descriptors for the same frame has to be set before, to
+		 * avoid race condition.
+		 */
+		wmb();
+
+	p->des3 = tdes3;
+}
+
+static void dwmac4_rd_prepare_tso_tx_desc(struct dma_desc *p, int is_fs,
+					  int len1, int len2, bool tx_own,
+					  bool ls, unsigned int tcphdrlen,
+					  unsigned int tcppayloadlen)
+{
+	unsigned int tdes3 = p->des3;
+
+	if (len1)
+		p->des2 |= (len1 & TDES2_BUFFER1_SIZE_MASK);
+
+	if (len2)
+		p->des2 |= (len2 << TDES2_BUFFER2_SIZE_MASK_SHIFT)
+			    & TDES2_BUFFER2_SIZE_MASK;
+
+	if (is_fs) {
+		tdes3 |= TDES3_FIRST_DESCRIPTOR |
+			 TDES3_TCP_SEGMENTATION_ENABLE |
+			 ((tcphdrlen << TDES3_HDR_LEN_SHIFT) &
+			  TDES3_SLOT_NUMBER_MASK) |
+			 ((tcppayloadlen & TDES3_TCP_PKT_PAYLOAD_MASK));
+	} else {
+		tdes3 &= ~TDES3_FIRST_DESCRIPTOR;
+	}
+
+	if (ls)
+		tdes3 |= TDES3_LAST_DESCRIPTOR;
+	else
+		tdes3 &= ~TDES3_LAST_DESCRIPTOR;
+
+	/* Finally set the OWN bit. Later the DMA will start! */
+	if (tx_own)
+		tdes3 |= TDES3_OWN;
+
+	if (is_fs & tx_own)
+		/* When the own bit, for the first frame, has to be set, all
+		 * descriptors for the same frame has to be set before, to
+		 * avoid race condition.
+		 */
+		wmb();
+
+	p->des3 = tdes3;
+}
+
+static void dwmac4_release_tx_desc(struct dma_desc *p, int mode)
+{
+	p->des2 = 0;
+	p->des3 = 0;
+}
+
+static void dwmac4_rd_set_tx_ic(struct dma_desc *p)
+{
+	p->des2 |= TDES2_INTERRUPT_ON_COMPLETION;
+}
+
+static void dwmac4_display_ring(void *head, unsigned int size, bool rx)
+{
+	struct dma_desc *p = (struct dma_desc *)head;
+	int i;
+
+	pr_info("%s descriptor ring:\n", rx ? "RX" : "TX");
+
+	for (i = 0; i < size; i++) {
+		if (p->des0)
+			pr_info("%d [0x%x]: 0x%x 0x%x 0x%x 0x%x\n",
+				i, (unsigned int)virt_to_phys(p),
+				p->des0, p->des1, p->des2, p->des3);
+		p++;
+	}
+}
+
+static void dwmac4_set_mss_ctxt(struct dma_desc *p, unsigned int mss)
+{
+	p->des0 = 0;
+	p->des1 = 0;
+	p->des2 = mss;
+	p->des3 = TDES3_CONTEXT_TYPE | TDES3_CTXT_TCMSSV;
+}
+
+const struct stmmac_desc_ops dwmac4_desc_ops = {
+	.tx_status = dwmac4_wrback_get_tx_status,
+	.rx_status = dwmac4_wrback_get_rx_status,
+	.get_tx_len = dwmac4_rd_get_tx_len,
+	.get_tx_owner = dwmac4_get_tx_owner,
+	.set_tx_owner = dwmac4_set_tx_owner,
+	.set_rx_owner = dwmac4_set_rx_owner,
+	.get_tx_ls = dwmac4_get_tx_ls,
+	.get_rx_frame_len = dwmac4_wrback_get_rx_frame_len,
+	.enable_tx_timestamp = dwmac4_rd_enable_tx_timestamp,
+	.get_tx_timestamp_status = dwmac4_wrback_get_tx_timestamp_status,
+	.get_timestamp = dwmac4_wrback_get_timestamp,
+	.get_rx_timestamp_status = dwmac4_context_get_rx_timestamp_status,
+	.set_tx_ic = dwmac4_rd_set_tx_ic,
+	.prepare_tx_desc = dwmac4_rd_prepare_tx_desc,
+	.prepare_tso_tx_desc = dwmac4_rd_prepare_tso_tx_desc,
+	.release_tx_desc = dwmac4_release_tx_desc,
+	.init_rx_desc = dwmac4_rd_init_rx_desc,
+	.init_tx_desc = dwmac4_rd_init_tx_desc,
+	.display_ring = dwmac4_display_ring,
+	.set_mss = dwmac4_set_mss_ctxt,
+};
+
+const struct stmmac_mode_ops dwmac4_ring_mode_ops = { };