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, 43 insertions, 28 deletions

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_vf.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_vf.c
index 35e06048356f..ced456cec8ba 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_vf.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_vf.c
@@ -89,16 +89,20 @@ static void otx2vf_vfaf_mbox_handler(struct work_struct *work)
 	struct otx2_mbox *mbox;
 	struct mbox *af_mbox;
 	int offset, id;
+	u16 num_msgs;
 
 	af_mbox = container_of(work, struct mbox, mbox_wrk);
 	mbox = &af_mbox->mbox;
 	mdev = &mbox->dev[0];
 	rsp_hdr = (struct mbox_hdr *)(mdev->mbase + mbox->rx_start);
-	if (af_mbox->num_msgs == 0)
+	num_msgs = rsp_hdr->num_msgs;
+
+	if (num_msgs == 0)
 		return;
+
 	offset = mbox->rx_start + ALIGN(sizeof(*rsp_hdr), MBOX_MSG_ALIGN);
 
-	for (id = 0; id < af_mbox->num_msgs; id++) {
+	for (id = 0; id < num_msgs; id++) {
 		msg = (struct mbox_msghdr *)(mdev->mbase + offset);
 		otx2vf_process_vfaf_mbox_msg(af_mbox->pfvf, msg);
 		offset = mbox->rx_start + msg->next_msgoff;
@@ -151,6 +155,7 @@ static void otx2vf_vfaf_mbox_up_handler(struct work_struct *work)
 	struct mbox *vf_mbox;
 	struct otx2_nic *vf;
 	int offset, id;
+	u16 num_msgs;
 
 	vf_mbox = container_of(work, struct mbox, mbox_up_wrk);
 	vf = vf_mbox->pfvf;
@@ -158,12 +163,14 @@ static void otx2vf_vfaf_mbox_up_handler(struct work_struct *work)
 	mdev = &mbox->dev[0];
 
 	rsp_hdr = (struct mbox_hdr *)(mdev->mbase + mbox->rx_start);
-	if (vf_mbox->up_num_msgs == 0)
+	num_msgs = rsp_hdr->num_msgs;
+
+	if (num_msgs == 0)
 		return;
 
 	offset = mbox->rx_start + ALIGN(sizeof(*rsp_hdr), MBOX_MSG_ALIGN);
 
-	for (id = 0; id < vf_mbox->up_num_msgs; id++) {
+	for (id = 0; id < num_msgs; id++) {
 		msg = (struct mbox_msghdr *)(mdev->mbase + offset);
 		otx2vf_process_mbox_msg_up(vf, msg);
 		offset = mbox->rx_start + msg->next_msgoff;
@@ -178,40 +185,48 @@ static irqreturn_t otx2vf_vfaf_mbox_intr_handler(int irq, void *vf_irq)
 	struct otx2_mbox_dev *mdev;
 	struct otx2_mbox *mbox;
 	struct mbox_hdr *hdr;
+	u64 mbox_data;
 
 	/* Clear the IRQ */
 	otx2_write64(vf, RVU_VF_INT, BIT_ULL(0));
 
+	mbox_data = otx2_read64(vf, RVU_VF_VFPF_MBOX0);
+
 	/* Read latest mbox data */
 	smp_rmb();
 
-	/* Check for PF => VF response messages */
-	mbox = &vf->mbox.mbox;
-	mdev = &mbox->dev[0];
-	otx2_sync_mbox_bbuf(mbox, 0);
+	if (mbox_data & MBOX_DOWN_MSG) {
+		mbox_data &= ~MBOX_DOWN_MSG;
+		otx2_write64(vf, RVU_VF_VFPF_MBOX0, mbox_data);
+
+		/* Check for PF => VF response messages */
+		mbox = &vf->mbox.mbox;
+		mdev = &mbox->dev[0];
+		otx2_sync_mbox_bbuf(mbox, 0);
 
-	trace_otx2_msg_interrupt(mbox->pdev, "PF to VF", BIT_ULL(0));
+		hdr = (struct mbox_hdr *)(mdev->mbase + mbox->rx_start);
+		if (hdr->num_msgs)
+			queue_work(vf->mbox_wq, &vf->mbox.mbox_wrk);
 
-	hdr = (struct mbox_hdr *)(mdev->mbase + mbox->rx_start);
-	if (hdr->num_msgs) {
-		vf->mbox.num_msgs = hdr->num_msgs;
-		hdr->num_msgs = 0;
-		memset(mbox->hwbase + mbox->rx_start, 0,
-		       ALIGN(sizeof(struct mbox_hdr), sizeof(u64)));
-		queue_work(vf->mbox_wq, &vf->mbox.mbox_wrk);
+		trace_otx2_msg_interrupt(mbox->pdev, "DOWN reply from PF to VF",
+					 BIT_ULL(0));
 	}
-	/* Check for PF => VF notification messages */
-	mbox = &vf->mbox.mbox_up;
-	mdev = &mbox->dev[0];
-	otx2_sync_mbox_bbuf(mbox, 0);
-
-	hdr = (struct mbox_hdr *)(mdev->mbase + mbox->rx_start);
-	if (hdr->num_msgs) {
-		vf->mbox.up_num_msgs = hdr->num_msgs;
-		hdr->num_msgs = 0;
-		memset(mbox->hwbase + mbox->rx_start, 0,
-		       ALIGN(sizeof(struct mbox_hdr), sizeof(u64)));
-		queue_work(vf->mbox_wq, &vf->mbox.mbox_up_wrk);
+
+	if (mbox_data & MBOX_UP_MSG) {
+		mbox_data &= ~MBOX_UP_MSG;
+		otx2_write64(vf, RVU_VF_VFPF_MBOX0, mbox_data);
+
+		/* Check for PF => VF notification messages */
+		mbox = &vf->mbox.mbox_up;
+		mdev = &mbox->dev[0];
+		otx2_sync_mbox_bbuf(mbox, 0);
+
+		hdr = (struct mbox_hdr *)(mdev->mbase + mbox->rx_start);
+		if (hdr->num_msgs)
+			queue_work(vf->mbox_wq, &vf->mbox.mbox_up_wrk);
+
+		trace_otx2_msg_interrupt(mbox->pdev, "UP message from PF to VF",
+					 BIT_ULL(0));
 	}
 
 	return IRQ_HANDLED;