[PATCH 4/8] scsi: megaraid_sas - check max_sgl reported by FW for setting max_sectors_per_req

[bo yang <bo.yang@lsi.com>]

1. Setting the max_sectors_per_req based on max SGL supported by the FW. Prior versions calculated  
        this value from controller info's max_sectors_1, max_sectors_2. For certain controllers/FW, 
        this was resulting in a value greater than max SGL supported by the FW. Now we take the min  
        of max sgl from FW and max_sectors calculation.

2. Increased MFI_POLL_TIMEOUT_SECS to 60 seconds from 10. FW may take a max of 60 seconds to  
        respond to the INIT cmd.

Signed-off-by: Bo Yang <bo.yang@lsi.com>

---
 drivers/scsi/megaraid/megaraid_sas.c |   13 +++++++++----
 drivers/scsi/megaraid/megaraid_sas.h |    2 +-
 2 files changed, 10 insertions(+), 5 deletions(-)

diff -uprN linux-2.6.22_orig/drivers/scsi/megaraid/megaraid_sas.c linux-2.6.22_new/drivers/scsi/megaraid/megaraid_sas.c
--- linux-2.6.22_orig/drivers/scsi/megaraid/megaraid_sas.c	2007-09-27 20:40:14.000000000 -0700
+++ linux-2.6.22_new/drivers/scsi/megaraid/megaraid_sas.c	2007-09-27 04:39:44.000000000 -0700
@@ -1960,6 +1960,7 @@ static int megasas_init_mfi(struct megas
 	u32 reply_q_sz;
 	u32 max_sectors_1;
 	u32 max_sectors_2;
+	u32 tmp_sectors;
 	struct megasas_register_set __iomem *reg_set;
 	struct megasas_ctrl_info *ctrl_info;
 	/*
@@ -2052,17 +2053,21 @@ static int megasas_init_mfi(struct megas
 	 * Note that older firmwares ( < FW ver 30) didn't report information
 	 * to calculate max_sectors_1. So the number ended up as zero always.
 	 */
+	tmp_sectors = 0;
 	if (ctrl_info && !megasas_get_ctrl_info(instance, ctrl_info)) {
 
 		max_sectors_1 = (1 << ctrl_info->stripe_sz_ops.min) *
 		    ctrl_info->max_strips_per_io;
 		max_sectors_2 = ctrl_info->max_request_size;
 
-		instance->max_sectors_per_req = (max_sectors_1 < max_sectors_2)
+		tmp_sectors = (max_sectors_1 < max_sectors_2)
 		    ? max_sectors_1 : max_sectors_2;
-	} else
-		instance->max_sectors_per_req = instance->max_num_sge *
-		    PAGE_SIZE / 512;
+	}
+
+	instance->max_sectors_per_req = instance->max_num_sge *
+						PAGE_SIZE / 512;
+	if (tmp_sectors && (instance->max_sectors_per_req > tmp_sectors))
+		instance->max_sectors_per_req = tmp_sectors;
 
 	kfree(ctrl_info);
 
diff -uprN linux-2.6.22_orig/drivers/scsi/megaraid/megaraid_sas.h linux-2.6.22_new/drivers/scsi/megaraid/megaraid_sas.h
--- linux-2.6.22_orig/drivers/scsi/megaraid/megaraid_sas.h	2007-09-26 13:40:36.000000000 -0700
+++ linux-2.6.22_new/drivers/scsi/megaraid/megaraid_sas.h	2007-09-26 14:10:59.000000000 -0700
@@ -572,7 +572,7 @@ struct megasas_ctrl_info {
 #define IS_DMA64				(sizeof(dma_addr_t) == 8)
 
 #define MFI_OB_INTR_STATUS_MASK			0x00000002
-#define MFI_POLL_TIMEOUT_SECS			10
+#define MFI_POLL_TIMEOUT_SECS			60
 
 #define MFI_REPLY_1078_MESSAGE_INTERRUPT	0x80000000