mpt3sas: Add support for configurable Chain Frame Size

Added support for configurable Chain Frame Size. Calculate the
Chain Message Frame size from the IOCMaxChainSegementSize (iocfacts).
Applicable only for mpt3sas/SAS3.0 HBA's.

Signed-off-by: Suganath prabu Subramani <suganath-prabu.subramani@avagotech.com>
Signed-off-by: Chaitra P B <chaitra.basappa@avagotech.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/mpt3sas/mpt3sas_base.c

@@ -3251,6 +3251,19 @@ _base_allocate_memory_pools(struct MPT3SAS_ADAPTER *ioc,  int sleep_flag)
 	/* reply frame size */
 	ioc->reply_sz = facts->ReplyFrameSize * 4;
 
+	/* chain segment size */
+	if (ioc->hba_mpi_version_belonged != MPI2_VERSION) {
+		if (facts->IOCMaxChainSegmentSize)
+			ioc->chain_segment_sz =
+					facts->IOCMaxChainSegmentSize *
+					MAX_CHAIN_ELEMT_SZ;
+		else
+		/* set to 128 bytes size if IOCMaxChainSegmentSize is zero */
+			ioc->chain_segment_sz = DEFAULT_NUM_FWCHAIN_ELEMTS *
+						    MAX_CHAIN_ELEMT_SZ;
+	} else
+		ioc->chain_segment_sz = ioc->request_sz;
+
 	/* calculate the max scatter element size */
 	sge_size = max_t(u16, ioc->sge_size, ioc->sge_size_ieee);
 
@@ -3262,7 +3275,7 @@ _base_allocate_memory_pools(struct MPT3SAS_ADAPTER *ioc,  int sleep_flag)
 	ioc->max_sges_in_main_message = max_sge_elements/sge_size;
 
 	/* now do the same for a chain buffer */
-	max_sge_elements = ioc->request_sz - sge_size;
+	max_sge_elements = ioc->chain_segment_sz - sge_size;
 	ioc->max_sges_in_chain_message = max_sge_elements/sge_size;
 
 	/*
@@ -3454,7 +3467,7 @@ _base_allocate_memory_pools(struct MPT3SAS_ADAPTER *ioc,  int sleep_flag)
 		goto out;
 	}
 	ioc->chain_dma_pool = pci_pool_create("chain pool", ioc->pdev,
-	    ioc->request_sz, 16, 0);
+	    ioc->chain_segment_sz, 16, 0);
 	if (!ioc->chain_dma_pool) {
 		pr_err(MPT3SAS_FMT "chain_dma_pool: pci_pool_create failed\n",
 			ioc->name);
@@ -3468,13 +3481,13 @@ _base_allocate_memory_pools(struct MPT3SAS_ADAPTER *ioc,  int sleep_flag)
 			ioc->chain_depth = i;
 			goto chain_done;
 		}
-		total_sz += ioc->request_sz;
+		total_sz += ioc->chain_segment_sz;
 	}
  chain_done:
 	dinitprintk(ioc, pr_info(MPT3SAS_FMT
 		"chain pool depth(%d), frame_size(%d), pool_size(%d kB)\n",
-		ioc->name, ioc->chain_depth, ioc->request_sz,
-		((ioc->chain_depth *  ioc->request_sz))/1024));
+		ioc->name, ioc->chain_depth, ioc->chain_segment_sz,
+		((ioc->chain_depth *  ioc->chain_segment_sz))/1024));
 
 	/* initialize hi-priority queue smid's */
 	ioc->hpr_lookup = kcalloc(ioc->hi_priority_depth,
@@ -4335,6 +4348,10 @@ _base_get_ioc_facts(struct MPT3SAS_ADAPTER *ioc, int sleep_flag)
 	facts->FWVersion.Word = le32_to_cpu(mpi_reply.FWVersion.Word);
 	facts->IOCRequestFrameSize =
 	    le16_to_cpu(mpi_reply.IOCRequestFrameSize);
+	if (ioc->hba_mpi_version_belonged != MPI2_VERSION) {
+		facts->IOCMaxChainSegmentSize =
+			le16_to_cpu(mpi_reply.IOCMaxChainSegmentSize);
+	}
 	facts->MaxInitiators = le16_to_cpu(mpi_reply.MaxInitiators);
 	facts->MaxTargets = le16_to_cpu(mpi_reply.MaxTargets);
 	ioc->shost->max_id = -1;

drivers/scsi/mpt3sas/mpt3sas_base.h

@@ -129,6 +129,9 @@
 
 #define MPT3SAS_INVALID_DEVICE_HANDLE	0xFFFF
 
+#define MAX_CHAIN_ELEMT_SZ		16
+#define DEFAULT_NUM_FWCHAIN_ELEMTS	8
+
 /*
  * reset phases
  */
@@ -759,7 +762,7 @@ struct mpt3sas_facts {
 	u32			IOCCapabilities;
 	union mpi3_version_union	FWVersion;
 	u16			IOCRequestFrameSize;
-	u16			Reserved3;
+	u16			IOCMaxChainSegmentSize;
 	u16			MaxInitiators;
 	u16			MaxTargets;
 	u16			MaxSasExpanders;
@@ -906,6 +909,8 @@ typedef void (*MPT3SAS_FLUSH_RUNNING_CMDS)(struct MPT3SAS_ADAPTER *ioc);
  * @max_sges_in_chain_message: number sg elements per chain
  * @chains_needed_per_io: max chains per io
  * @chain_depth: total chains allocated
+ * @chain_segment_sz: gives the max number of
+ *			SGEs accommodate on single chain buffer
  * @hi_priority_smid:
  * @hi_priority:
  * @hi_priority_dma:
@@ -1113,6 +1118,7 @@ struct MPT3SAS_ADAPTER {
 	u16		max_sges_in_chain_message;
 	u16		chains_needed_per_io;
 	u32		chain_depth;
+	u16		chain_segment_sz;
 
 	/* hi-priority queue */
 	u16		hi_priority_smid;