[PATCH v8 net-next 08/15] net: enetc: add multiple command BD rings support

[Wei Fang]

All the tables of NETC switch are managed through the command BD ring,
but unlike ENETC, the switch has two command BD rings, if the current
ring is busy, the switch driver can switch to another ring to manage
the table. Currently, the NTMP driver does not support multiple rings.
Therefore, update ntmp_select_and_lock_cbdr() to select a appropriate
ring to execute the command for the switch.

Signed-off-by: Wei Fang <wei.fang@xxxxxxx>
---
 drivers/net/ethernet/freescale/enetc/ntmp.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/freescale/enetc/ntmp.c b/drivers/net/ethernet/freescale/enetc/ntmp.c
index 635032d24dc7..f71cad943424 100644
--- a/drivers/net/ethernet/freescale/enetc/ntmp.c
+++ b/drivers/net/ethernet/freescale/enetc/ntmp.c
@@ -146,11 +146,16 @@ static void ntmp_clean_cbdr(struct netc_cbdr *cbdr)
 static void ntmp_select_and_lock_cbdr(struct ntmp_user *user,
 				      struct netc_cbdr **cbdr)
 {
-	/* Currently only ENETC is supported, and it has only one command
-	 * BD ring.
-	 */
-	*cbdr = &user->ring[0];
+	for (int i = 0; i < user->cbdr_num; i++) {
+		*cbdr = &user->ring[i];
+		if (mutex_trylock(&(*cbdr)->ring_lock))
+			return;
+	}
 
+	/* If all command BD rings are locked, we need to select one of
+	 * them and wait for it.
+	 */
+	*cbdr = &user->ring[raw_smp_processor_id() % user->cbdr_num];
 	mutex_lock(&(*cbdr)->ring_lock);
 }
 
-- 
2.34.1