octeontx2: Detect the mbox up or down message via register

A single line of interrupt is used to receive up notifications
and down reply messages from AF to PF (similarly from PF to its VF).
PF acts as bridge and forwards VF messages to AF and sends respsones
back from AF to VF. When an async event like link event is received
by up message when PF is in middle of forwarding VF message then
mailbox errors occur because PF state machine is corrupted.
Since VF is a separate driver or VF driver can be in a VM it is
not possible to serialize from the start of communication at VF.
Hence to differentiate between type of messages at PF this patch makes
sender to set mbox data register with distinct values for up and down
messages. Sender also checks whether previous interrupt is received
before triggering current interrupt by waiting for mailbox data register
to become zero.

Fixes: 5a6d7c9daef3 ("octeontx2-pf: Mailbox communication with AF")
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 3 deletions

diff --git a/drivers/net/ethernet/marvell/octeontx2/af/rvu.c b/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
index 07d4859de53a..0b65a18c3a88 100644
--- a/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
+++ b/drivers/net/ethernet/marvell/octeontx2/af/rvu.c
@@ -2119,7 +2119,7 @@ bad_message:
 	}
 }
 
-static void __rvu_mbox_handler(struct rvu_work *mwork, int type)
+static void __rvu_mbox_handler(struct rvu_work *mwork, int type, bool poll)
 {
 	struct rvu *rvu = mwork->rvu;
 	int offset, err, id, devid;
@@ -2186,6 +2186,9 @@ static void __rvu_mbox_handler(struct rvu_work *mwork, int type)
 	}
 	mw->mbox_wrk[devid].num_msgs = 0;
 
+	if (poll)
+		otx2_mbox_wait_for_zero(mbox, devid);
+
 	/* Send mbox responses to VF/PF */
 	otx2_mbox_msg_send(mbox, devid);
 }
@@ -2193,15 +2196,18 @@ static void __rvu_mbox_handler(struct rvu_work *mwork, int type)
 static inline void rvu_afpf_mbox_handler(struct work_struct *work)
 {
 	struct rvu_work *mwork = container_of(work, struct rvu_work, work);
+	struct rvu *rvu = mwork->rvu;
 
-	__rvu_mbox_handler(mwork, TYPE_AFPF);
+	mutex_lock(&rvu->mbox_lock);
+	__rvu_mbox_handler(mwork, TYPE_AFPF, true);
+	mutex_unlock(&rvu->mbox_lock);
 }
 
 static inline void rvu_afvf_mbox_handler(struct work_struct *work)
 {
 	struct rvu_work *mwork = container_of(work, struct rvu_work, work);
 
-	__rvu_mbox_handler(mwork, TYPE_AFVF);
+	__rvu_mbox_handler(mwork, TYPE_AFVF, false);
 }
 
 static void __rvu_mbox_up_handler(struct rvu_work *mwork, int type)
@@ -2376,6 +2382,8 @@ static int rvu_mbox_init(struct rvu *rvu, struct mbox_wq_info *mw,
 		}
 	}
 
+	mutex_init(&rvu->mbox_lock);
+
 	mbox_regions = kcalloc(num, sizeof(void *), GFP_KERNEL);
 	if (!mbox_regions) {
 		err = -ENOMEM;