cxgb4: use backdoor access to collect dumps when firmware crashed

Fallback to backdoor register access to collect dumps if firmware
is crashed.  Fixes TID, SGE Queue Context, and MPS TCAM dump collection.

Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/cudbg_lib.c

@@ -1567,6 +1567,12 @@ int cudbg_collect_tid(struct cudbg_init *pdbg_init,
 	tid1->ver_hdr.size = sizeof(struct cudbg_tid_info_region_rev1) -
 			     sizeof(struct cudbg_ver_hdr);
 
+	/* If firmware is not attached/alive, use backdoor register
+	 * access to collect dump.
+	 */
+	if (!is_fw_attached(pdbg_init))
+		goto fill_tid;
+
 #define FW_PARAM_PFVF_A(param) \
 	(FW_PARAMS_MNEM_V(FW_PARAMS_MNEM_PFVF) | \
 	 FW_PARAMS_PARAM_X_V(FW_PARAMS_PARAM_PFVF_##param) | \
@@ -1604,6 +1610,9 @@ int cudbg_collect_tid(struct cudbg_init *pdbg_init,
 		tid->nhpftids = val[1] - val[0] + 1;
 	}
 
+#undef FW_PARAM_PFVF_A
+
+fill_tid:
 	tid->ntids = padap->tids.ntids;
 	tid->nstids = padap->tids.nstids;
 	tid->stid_base = padap->tids.stid_base;
@@ -1623,8 +1632,6 @@ int cudbg_collect_tid(struct cudbg_init *pdbg_init,
 	tid->ip_users = t4_read_reg(padap, LE_DB_ACT_CNT_IPV4_A);
 	tid->ipv6_users = t4_read_reg(padap, LE_DB_ACT_CNT_IPV6_A);
 
-#undef FW_PARAM_PFVF_A
-
 	return cudbg_write_and_release_buff(pdbg_init, &temp_buff, dbg_buff);
 }
 
@@ -1866,11 +1873,18 @@ int cudbg_collect_dump_context(struct cudbg_init *pdbg_init,
 		max_ctx_size = region_info[i].end - region_info[i].start + 1;
 		max_ctx_qid = max_ctx_size / SGE_CTXT_SIZE;
 
-		t4_sge_ctxt_flush(padap, padap->mbox, i);
-		rc = t4_memory_rw(padap, MEMWIN_NIC, mem_type[i],
-				  region_info[i].start, max_ctx_size,
-				  (__be32 *)ctx_buf, 1);
-		if (rc) {
+		/* If firmware is not attached/alive, use backdoor register
+		 * access to collect dump.
+		 */
+		if (is_fw_attached(pdbg_init)) {
+			t4_sge_ctxt_flush(padap, padap->mbox, i);
+
+			rc = t4_memory_rw(padap, MEMWIN_NIC, mem_type[i],
+					  region_info[i].start, max_ctx_size,
+					  (__be32 *)ctx_buf, 1);
+		}
+
+		if (rc || !is_fw_attached(pdbg_init)) {
 			max_ctx_qid = CUDBG_LOWMEM_MAX_CTXT_QIDS;
 			cudbg_get_sge_ctxt_fw(pdbg_init, max_ctx_qid, i,
 					      &buff);
@@ -1946,9 +1960,10 @@ static void cudbg_mps_rpl_backdoor(struct adapter *padap,
 	mps_rplc->rplc31_0 = htonl(t4_read_reg(padap, MPS_VF_RPLCT_MAP0_A));
 }
 
-static int cudbg_collect_tcam_index(struct adapter *padap,
+static int cudbg_collect_tcam_index(struct cudbg_init *pdbg_init,
 				    struct cudbg_mps_tcam *tcam, u32 idx)
 {
+	struct adapter *padap = pdbg_init->adap;
 	u64 tcamy, tcamx, val;
 	u32 ctl, data2;
 	int rc = 0;
@@ -2033,12 +2048,22 @@ static int cudbg_collect_tcam_index(struct adapter *padap,
 			htons(FW_LDST_CMD_FID_V(FW_LDST_MPS_RPLC) |
 			      FW_LDST_CMD_IDX_V(idx));
 
-		rc = t4_wr_mbox(padap, padap->mbox, &ldst_cmd, sizeof(ldst_cmd),
-				&ldst_cmd);
-		if (rc)
+		/* If firmware is not attached/alive, use backdoor register
+		 * access to collect dump.
+		 */
+		if (is_fw_attached(pdbg_init))
+			rc = t4_wr_mbox(padap, padap->mbox, &ldst_cmd,
+					sizeof(ldst_cmd), &ldst_cmd);
+
+		if (rc || !is_fw_attached(pdbg_init)) {
 			cudbg_mps_rpl_backdoor(padap, &mps_rplc);
-		else
+			/* Ignore error since we collected directly from
+			 * reading registers.
+			 */
+			rc = 0;
+		} else {
 			mps_rplc = ldst_cmd.u.mps.rplc;
+		}
 
 		tcam->rplc[0] = ntohl(mps_rplc.rplc31_0);
 		tcam->rplc[1] = ntohl(mps_rplc.rplc63_32);
@@ -2075,7 +2100,7 @@ int cudbg_collect_mps_tcam(struct cudbg_init *pdbg_init,
 
 	tcam = (struct cudbg_mps_tcam *)temp_buff.data;
 	for (i = 0; i < n; i++) {
-		rc = cudbg_collect_tcam_index(padap, tcam, i);
+		rc = cudbg_collect_tcam_index(pdbg_init, tcam, i);
 		if (rc) {
 			cudbg_err->sys_err = rc;
 			cudbg_put_buff(pdbg_init, &temp_buff);