[PATCH 2/6] ntb_hw_switchtec: Fix bug with more than 32 partitions

[Kelvin Cao <kelvin.cao@xxxxxxxxxxxxx>]

From: Wesley Sheng <wesley.sheng@xxxxxxxxxxxxx>

Switchtec could support as mush as 48 partitions, but ffs & fls are
for 32 bit argument, in case of partition index larger than 31, the
current code could not parse the peer partition index correctly.
Change to the 64 bit version __ffs64 & fls64 accordingly to fix this
bug.

Fixes: 3df54c870f52 ("ntb_hw_switchtec: Allow using Switchtec NTB in multi-partition setups")
Signed-off-by: Wesley Sheng <wesley.sheng@xxxxxxxxxxxxx>
Signed-off-by: Kelvin Cao <kelvin.cao@xxxxxxxxxxxxx>
---
 drivers/ntb/hw/mscc/ntb_hw_switchtec.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c
index 6603c77c0a84..ec9cb6c81eda 100644
--- a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c
+++ b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c
@@ -840,7 +840,6 @@ static int switchtec_ntb_init_sndev(struct switchtec_ntb *sndev)
 	u64 tpart_vec;
 	int self;
 	u64 part_map;
-	int bit;
 
 	sndev->ntb.pdev = sndev->stdev->pdev;
 	sndev->ntb.topo = NTB_TOPO_SWITCH;
@@ -861,29 +860,28 @@ static int switchtec_ntb_init_sndev(struct switchtec_ntb *sndev)
 	part_map = ioread64(&sndev->mmio_ntb->ep_map);
 	part_map &= ~(1 << sndev->self_partition);
 
-	if (!ffs(tpart_vec)) {
+	if (!tpart_vec) {
 		if (sndev->stdev->partition_count != 2) {
 			dev_err(&sndev->stdev->dev,
 				"ntb target partition not defined\n");
 			return -ENODEV;
 		}
 
-		bit = ffs(part_map);
-		if (!bit) {
+		if (!part_map) {
 			dev_err(&sndev->stdev->dev,
 				"peer partition is not NT partition\n");
 			return -ENODEV;
 		}
 
-		sndev->peer_partition = bit - 1;
+		sndev->peer_partition = __ffs64(part_map);
 	} else {
-		if (ffs(tpart_vec) != fls(tpart_vec)) {
+		if (__ffs64(tpart_vec) != (fls64(tpart_vec) - 1)) {
 			dev_err(&sndev->stdev->dev,
 				"ntb driver only supports 1 pair of 1-1 ntb mapping\n");
 			return -ENODEV;
 		}
 
-		sndev->peer_partition = ffs(tpart_vec) - 1;
+		sndev->peer_partition = __ffs64(tpart_vec);
 		if (!(part_map & (1ULL << sndev->peer_partition))) {
 			dev_err(&sndev->stdev->dev,
 				"ntb target partition is not NT partition\n");
-- 
2.25.1