scsi: cxgb4i: Add support for iSCSI segmentation offload

T5/T6 adapters support iSCSI segmentation offload.

To transmit iSCSI PDUs using ISO driver provides iSCSI header and data
scatterlist to the adapter, adapter forms multiple iSCSI PDUs and transmits
them.

[mkp: checkpatch]

Link: https://lore.kernel.org/r/1593448871-2972-1-git-send-email-varun@chelsio.comSigned-off-by: Varun Prakash <varun@chelsio.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/cxgbi/cxgb3i/cxgb3i.c

@@ -361,7 +361,7 @@ static inline void make_tx_data_wr(struct cxgbi_sock *csk, struct sk_buff *skb,
 	/* len includes the length of any HW ULP additions */
 	req->len = htonl(len);
 	/* V_TX_ULP_SUBMODE sets both the mode and submode */
-	req->flags = htonl(V_TX_ULP_SUBMODE(cxgbi_skcb_ulp_mode(skb)) |
+	req->flags = htonl(V_TX_ULP_SUBMODE(cxgbi_skcb_tx_ulp_mode(skb)) |
 			   V_TX_SHOVE((skb_peek(&csk->write_queue) ? 0 : 1)));
 	req->sndseq = htonl(csk->snd_nxt);
 	req->param = htonl(V_TX_PORT(l2t->smt_idx));
@@ -442,7 +442,7 @@ static int push_tx_frames(struct cxgbi_sock *csk, int req_completion)
 				req_completion = 1;
 				csk->wr_una_cred = 0;
 			}
-			len += cxgbi_ulp_extra_len(cxgbi_skcb_ulp_mode(skb));
+			len += cxgbi_ulp_extra_len(cxgbi_skcb_tx_ulp_mode(skb));
 			make_tx_data_wr(csk, skb, len, req_completion);
 			csk->snd_nxt += len;
 			cxgbi_skcb_clear_flag(skb, SKCBF_TX_NEED_HDR);

drivers/scsi/cxgbi/libcxgbi.h

@@ -76,6 +76,14 @@ do {									\
 #define ULP2_MAX_PDU_PAYLOAD	\
 	(ULP2_MAX_PKT_SIZE - ISCSI_PDU_NONPAYLOAD_LEN)
 
+#define CXGBI_ULP2_MAX_ISO_PAYLOAD	65535
+
+#define CXGBI_MAX_ISO_DATA_IN_SKB	\
+	min_t(u32, MAX_SKB_FRAGS << PAGE_SHIFT, CXGBI_ULP2_MAX_ISO_PAYLOAD)
+
+#define cxgbi_is_iso_config(csk)	((csk)->cdev->skb_iso_txhdr)
+#define cxgbi_is_iso_disabled(csk)	((csk)->disable_iso)
+
 /*
  * For iscsi connections HW may inserts digest bytes into the pdu. Those digest
  * bytes are not sent by the host but are part of the TCP payload and therefore
@@ -162,6 +170,10 @@ struct cxgbi_sock {
 	u32 write_seq;
 	u32 snd_win;
 	u32 rcv_win;
+
+	bool disable_iso;
+	u32 no_tx_credits;
+	unsigned long prev_iso_ts;
 };
 
 /*
@@ -203,6 +215,8 @@ struct cxgbi_skb_tx_cb {
 	void *handle;
 	void *arp_err_handler;
 	struct sk_buff *wr_next;
+	u16 iscsi_hdr_len;
+	u8 ulp_mode;
 };
 
 enum cxgbi_skcb_flags {
@@ -218,6 +232,7 @@ enum cxgbi_skcb_flags {
 	SKCBF_RX_HCRC_ERR,	/* header digest error */
 	SKCBF_RX_DCRC_ERR,	/* data digest error */
 	SKCBF_RX_PAD_ERR,	/* padding byte error */
+	SKCBF_TX_ISO,		/* iso cpl in tx skb */
 };
 
 struct cxgbi_skb_cb {
@@ -225,18 +240,18 @@ struct cxgbi_skb_cb {
 		struct cxgbi_skb_rx_cb rx;
 		struct cxgbi_skb_tx_cb tx;
 	};
-	unsigned char ulp_mode;
 	unsigned long flags;
 	unsigned int seq;
 };
 
 #define CXGBI_SKB_CB(skb)	((struct cxgbi_skb_cb *)&((skb)->cb[0]))
 #define cxgbi_skcb_flags(skb)		(CXGBI_SKB_CB(skb)->flags)
-#define cxgbi_skcb_ulp_mode(skb)	(CXGBI_SKB_CB(skb)->ulp_mode)
 #define cxgbi_skcb_tcp_seq(skb)		(CXGBI_SKB_CB(skb)->seq)
 #define cxgbi_skcb_rx_ddigest(skb)	(CXGBI_SKB_CB(skb)->rx.ddigest)
 #define cxgbi_skcb_rx_pdulen(skb)	(CXGBI_SKB_CB(skb)->rx.pdulen)
 #define cxgbi_skcb_tx_wr_next(skb)	(CXGBI_SKB_CB(skb)->tx.wr_next)
+#define cxgbi_skcb_tx_iscsi_hdrlen(skb)	(CXGBI_SKB_CB(skb)->tx.iscsi_hdr_len)
+#define cxgbi_skcb_tx_ulp_mode(skb)	(CXGBI_SKB_CB(skb)->tx.ulp_mode)
 
 static inline void cxgbi_skcb_set_flag(struct sk_buff *skb,
 					enum cxgbi_skcb_flags flag)
@@ -458,6 +473,7 @@ struct cxgbi_ports_map {
 #define CXGBI_FLAG_IPV4_SET		0x10
 #define CXGBI_FLAG_USE_PPOD_OFLDQ       0x40
 #define CXGBI_FLAG_DDP_OFF		0x100
+#define CXGBI_FLAG_DEV_ISO_OFF		0x400
 
 struct cxgbi_device {
 	struct list_head list_head;
@@ -477,6 +493,7 @@ struct cxgbi_device {
 	unsigned int pfvf;
 	unsigned int rx_credit_thres;
 	unsigned int skb_tx_rsvd;
+	u32 skb_iso_txhdr;
 	unsigned int skb_rx_extra;	/* for msg coalesced mode */
 	unsigned int tx_max_size;
 	unsigned int rx_max_size;
@@ -523,20 +540,41 @@ struct cxgbi_endpoint {
 	struct cxgbi_sock *csk;
 };
 
-#define MAX_PDU_FRAGS	((ULP2_MAX_PDU_PAYLOAD + 512 - 1) / 512)
 struct cxgbi_task_data {
+#define CXGBI_TASK_SGL_CHECKED	0x1
+#define CXGBI_TASK_SGL_COPY	0x2
+	u8 flags;
 	unsigned short nr_frags;
-	struct page_frag frags[MAX_PDU_FRAGS];
+	struct page_frag frags[MAX_SKB_FRAGS];
 	struct sk_buff *skb;
 	unsigned int dlen;
 	unsigned int offset;
 	unsigned int count;
 	unsigned int sgoffset;
+	u32 total_count;
+	u32 total_offset;
+	u32 max_xmit_dlength;
 	struct cxgbi_task_tag_info ttinfo;
 };
 #define iscsi_task_cxgbi_data(task) \
 	((task)->dd_data + sizeof(struct iscsi_tcp_task))
 
+struct cxgbi_iso_info {
+#define CXGBI_ISO_INFO_FSLICE		0x1
+#define CXGBI_ISO_INFO_LSLICE		0x2
+#define CXGBI_ISO_INFO_IMM_ENABLE	0x4
+	u8 flags;
+	u8 op;
+	u8 ahs;
+	u8 num_pdu;
+	u32 mpdu;
+	u32 burst_size;
+	u32 len;
+	u32 segment_offset;
+	u32 datasn_offset;
+	u32 buffer_offset;
+};
+
 static inline void *cxgbi_alloc_big_mem(unsigned int size,
 					gfp_t gfp)
 {