idpf: add splitq start_xmit

Add start_xmit support for split queue model. To start with, add the
necessary checks to linearize the skb if it uses more number of
buffers than the hardware supported limit. Stop the transmit queue
if there are no enough descriptors available for the skb to use or
if there we're going to potentially overrun the completion queue.
Finally prepare the descriptor with all the required
information and update the tail.

Signed-off-by: Joshua Hay <[email protected]>
Co-developed-by: Alan Brady <[email protected]>
Signed-off-by: Alan Brady <[email protected]>
Co-developed-by: Madhu Chittim <[email protected]>
Signed-off-by: Madhu Chittim <[email protected]>
Co-developed-by: Phani Burra <[email protected]>
Signed-off-by: Phani Burra <[email protected]>
Reviewed-by: Sridhar Samudrala <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Co-developed-by: Pavan Kumar Linga <[email protected]>
Signed-off-by: Pavan Kumar Linga <[email protected]>
Signed-off-by: Tony Nguyen <[email protected]>

Author: jahay1

drivers/net/ethernet/intel/idpf/idpf.h

@@ -13,6 +13,7 @@ struct idpf_vport_max_q;
 #include <linux/aer.h>
 #include <linux/etherdevice.h>
 #include <linux/pci.h>
+#include <linux/bitfield.h>
 
 #include "virtchnl2.h"
 #include "idpf_lan_txrx.h"

drivers/net/ethernet/intel/idpf/idpf_lan_txrx.h

@@ -56,6 +56,64 @@ enum idpf_rss_hash {
 	BIT_ULL(IDPF_HASH_NONF_UNICAST_IPV6_UDP) |		\
 	BIT_ULL(IDPF_HASH_NONF_MULTICAST_IPV6_UDP))
 
+#define IDPF_TXD_CTX_QW1_MSS_S		50
+#define IDPF_TXD_CTX_QW1_MSS_M		GENMASK_ULL(63, 50)
+#define IDPF_TXD_CTX_QW1_TSO_LEN_S	30
+#define IDPF_TXD_CTX_QW1_TSO_LEN_M	GENMASK_ULL(47, 30)
+#define IDPF_TXD_CTX_QW1_CMD_S		4
+#define IDPF_TXD_CTX_QW1_CMD_M		GENMASK_ULL(15, 4)
+#define IDPF_TXD_CTX_QW1_DTYPE_S	0
+#define IDPF_TXD_CTX_QW1_DTYPE_M	GENMASK_ULL(3, 0)
+#define IDPF_TXD_QW1_L2TAG1_S		48
+#define IDPF_TXD_QW1_L2TAG1_M		GENMASK_ULL(63, 48)
+#define IDPF_TXD_QW1_TX_BUF_SZ_S	34
+#define IDPF_TXD_QW1_TX_BUF_SZ_M	GENMASK_ULL(47, 34)
+#define IDPF_TXD_QW1_OFFSET_S		16
+#define IDPF_TXD_QW1_OFFSET_M		GENMASK_ULL(33, 16)
+#define IDPF_TXD_QW1_CMD_S		4
+#define IDPF_TXD_QW1_CMD_M		GENMASK_ULL(15, 4)
+#define IDPF_TXD_QW1_DTYPE_S		0
+#define IDPF_TXD_QW1_DTYPE_M		GENMASK_ULL(3, 0)
+
+enum idpf_tx_desc_dtype_value {
+	IDPF_TX_DESC_DTYPE_DATA				= 0,
+	IDPF_TX_DESC_DTYPE_CTX				= 1,
+	/* DTYPE 2 is reserved
+	 * DTYPE 3 is free for future use
+	 * DTYPE 4 is reserved
+	 */
+	IDPF_TX_DESC_DTYPE_FLEX_TSO_CTX			= 5,
+	/* DTYPE 6 is reserved */
+	IDPF_TX_DESC_DTYPE_FLEX_L2TAG1_L2TAG2		= 7,
+	/* DTYPE 8, 9 are free for future use
+	 * DTYPE 10 is reserved
+	 * DTYPE 11 is free for future use
+	 */
+	IDPF_TX_DESC_DTYPE_FLEX_FLOW_SCHE		= 12,
+	/* DTYPE 13, 14 are free for future use */
+
+	/* DESC_DONE - HW has completed write-back of descriptor */
+	IDPF_TX_DESC_DTYPE_DESC_DONE			= 15,
+};
+
+enum idpf_tx_base_desc_cmd_bits {
+	IDPF_TX_DESC_CMD_EOP			= BIT(0),
+	IDPF_TX_DESC_CMD_RS			= BIT(1),
+	 /* only on VFs else RSVD */
+	IDPF_TX_DESC_CMD_ICRC			= BIT(2),
+	IDPF_TX_DESC_CMD_IL2TAG1		= BIT(3),
+	IDPF_TX_DESC_CMD_RSVD1			= BIT(4),
+	IDPF_TX_DESC_CMD_IIPT_IPV6		= BIT(5),
+	IDPF_TX_DESC_CMD_IIPT_IPV4		= BIT(6),
+	IDPF_TX_DESC_CMD_IIPT_IPV4_CSUM		= GENMASK(6, 5),
+	IDPF_TX_DESC_CMD_RSVD2			= BIT(7),
+	IDPF_TX_DESC_CMD_L4T_EOFT_TCP		= BIT(8),
+	IDPF_TX_DESC_CMD_L4T_EOFT_SCTP		= BIT(9),
+	IDPF_TX_DESC_CMD_L4T_EOFT_UDP		= GENMASK(9, 8),
+	IDPF_TX_DESC_CMD_RSVD3			= BIT(10),
+	IDPF_TX_DESC_CMD_RSVD4			= BIT(11),
+};
+
 /* Transmit descriptors  */
 /* splitq tx buf, singleq tx buf and singleq compl desc */
 struct idpf_base_tx_desc {
@@ -74,4 +132,89 @@ struct idpf_splitq_tx_compl_desc {
 	u8 rsvd; /* Reserved */
 }; /* writeback used with completion queues */
 
+/* Common cmd field defines for all desc except Flex Flow Scheduler (0x0C) */
+enum idpf_tx_flex_desc_cmd_bits {
+	IDPF_TX_FLEX_DESC_CMD_EOP			= BIT(0),
+	IDPF_TX_FLEX_DESC_CMD_RS			= BIT(1),
+	IDPF_TX_FLEX_DESC_CMD_RE			= BIT(2),
+	IDPF_TX_FLEX_DESC_CMD_IL2TAG1			= BIT(3),
+	IDPF_TX_FLEX_DESC_CMD_DUMMY			= BIT(4),
+	IDPF_TX_FLEX_DESC_CMD_CS_EN			= BIT(5),
+	IDPF_TX_FLEX_DESC_CMD_FILT_AU_EN		= BIT(6),
+	IDPF_TX_FLEX_DESC_CMD_FILT_AU_EVICT		= BIT(7),
+};
+
+struct idpf_flex_tx_desc {
+	__le64 buf_addr;	/* Packet buffer address */
+	struct {
+#define IDPF_FLEX_TXD_QW1_DTYPE_S	0
+#define IDPF_FLEX_TXD_QW1_DTYPE_M	GENMASK(4, 0)
+#define IDPF_FLEX_TXD_QW1_CMD_S		5
+#define IDPF_FLEX_TXD_QW1_CMD_M		GENMASK(15, 5)
+		__le16 cmd_dtype;
+		/* DTYPE=IDPF_TX_DESC_DTYPE_FLEX_L2TAG1_L2TAG2 (0x07) */
+		struct {
+			__le16 l2tag1;
+			__le16 l2tag2;
+		} l2tags;
+		__le16 buf_size;
+	} qw1;
+};
+
+struct idpf_flex_tx_sched_desc {
+	__le64 buf_addr;	/* Packet buffer address */
+
+	/* DTYPE = IDPF_TX_DESC_DTYPE_FLEX_FLOW_SCHE_16B (0x0C) */
+	struct {
+		u8 cmd_dtype;
+#define IDPF_TXD_FLEX_FLOW_DTYPE_M	GENMASK(4, 0)
+#define IDPF_TXD_FLEX_FLOW_CMD_EOP	BIT(5)
+#define IDPF_TXD_FLEX_FLOW_CMD_CS_EN	BIT(6)
+#define IDPF_TXD_FLEX_FLOW_CMD_RE	BIT(7)
+
+		/* [23:23] Horizon Overflow bit, [22:0] timestamp */
+		u8 ts[3];
+#define IDPF_TXD_FLOW_SCH_HORIZON_OVERFLOW_M	BIT(7)
+
+		__le16 compl_tag;
+		__le16 rxr_bufsize;
+#define IDPF_TXD_FLEX_FLOW_RXR		BIT(14)
+#define IDPF_TXD_FLEX_FLOW_BUFSIZE_M	GENMASK(13, 0)
+	} qw1;
+};
+
+/* Common cmd fields for all flex context descriptors
+ * Note: these defines already account for the 5 bit dtype in the cmd_dtype
+ * field
+ */
+enum idpf_tx_flex_ctx_desc_cmd_bits {
+	IDPF_TX_FLEX_CTX_DESC_CMD_TSO			= BIT(5),
+	IDPF_TX_FLEX_CTX_DESC_CMD_TSYN_EN		= BIT(6),
+	IDPF_TX_FLEX_CTX_DESC_CMD_L2TAG2		= BIT(7),
+	IDPF_TX_FLEX_CTX_DESC_CMD_SWTCH_UPLNK		= BIT(9),
+	IDPF_TX_FLEX_CTX_DESC_CMD_SWTCH_LOCAL		= BIT(10),
+	IDPF_TX_FLEX_CTX_DESC_CMD_SWTCH_TARGETVSI	= GENMASK(10, 9),
+};
+
+/* Standard flex descriptor TSO context quad word */
+struct idpf_flex_tx_tso_ctx_qw {
+	__le32 flex_tlen;
+#define IDPF_TXD_FLEX_CTX_TLEN_M	GENMASK(17, 0)
+#define IDPF_TXD_FLEX_TSO_CTX_FLEX_S	24
+	__le16 mss_rt;
+#define IDPF_TXD_FLEX_CTX_MSS_RT_M	GENMASK(13, 0)
+	u8 hdr_len;
+	u8 flex;
+};
+
+struct idpf_flex_tx_ctx_desc {
+	/* DTYPE = IDPF_TX_DESC_DTYPE_FLEX_TSO_CTX (0x05) */
+	struct {
+		struct idpf_flex_tx_tso_ctx_qw qw0;
+		struct {
+			__le16 cmd_dtype;
+			u8 flex[6];
+		} qw1;
+	} tso;
+};
 #endif /* _IDPF_LAN_TXRX_H_ */

drivers/net/ethernet/intel/idpf/idpf_lib.c

@@ -1557,6 +1557,7 @@ void idpf_free_dma_mem(struct idpf_hw *hw, struct idpf_dma_mem *mem)
 static const struct net_device_ops idpf_netdev_ops_splitq = {
 	.ndo_open = idpf_open,
 	.ndo_stop = idpf_stop,
+	.ndo_start_xmit = idpf_tx_splitq_start,
 };
 
 static const struct net_device_ops idpf_netdev_ops_singleq = {