[PATCH v2 for-next 2/3] IB/hfi1: Add mtu check for operational data VLs

[Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>]

From: Alex Estrin <alex.estrin@xxxxxxxxx>

Since Virtual Lanes BCT credits and MTU are set through
separate MADs, we have to ensure both are valid, and data VLs
are ready for transmission before we allow port transition
to Armed state.

Fixes: 5e2d6764a729 ("IB/hfi1: Verify port data VLs credits on transition to Armed")
Reviewed-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx>
Signed-off-by: Alex Estrin <alex.estrin@xxxxxxxxx>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
---
 drivers/infiniband/hw/hfi1/chip.c |   26 ++++++++++++++++++++++----
 1 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/chip.c b/drivers/infiniband/hw/hfi1/chip.c
index bdcc4f1..9b20479 100644
--- a/drivers/infiniband/hw/hfi1/chip.c
+++ b/drivers/infiniband/hw/hfi1/chip.c
@@ -10561,12 +10561,29 @@ void set_link_down_reason(struct hfi1_pportdata *ppd, u8 lcl_reason,
 	}
 }
 
-/*
- * Verify if BCT for data VLs is non-zero.
+/**
+ * data_vls_operational() - Verify if data VL BCT credits and MTU
+ *			    are both set.
+ * @ppd: pointer to hfi1_pportdata structure
+ *
+ * Return: true - Ok, false -otherwise.
  */
 static inline bool data_vls_operational(struct hfi1_pportdata *ppd)
 {
-	return !!ppd->actual_vls_operational;
+	int i;
+	u64 reg;
+
+	if (!ppd->actual_vls_operational)
+		return false;
+
+	for (i = 0; i < ppd->vls_supported; i++) {
+		reg = read_csr(ppd->dd, SEND_CM_CREDIT_VL + (8 * i));
+		if ((reg && !ppd->dd->vld[i].mtu) ||
+		    (!reg && ppd->dd->vld[i].mtu))
+			return false;
+	}
+
+	return true;
 }
 
 /*
@@ -10679,7 +10696,8 @@ int set_link_state(struct hfi1_pportdata *ppd, u32 state)
 
 		if (!data_vls_operational(ppd)) {
 			dd_dev_err(dd,
-				   "%s: data VLs not operational\n", __func__);
+				   "%s: Invalid data VL credits or mtu\n",
+				   __func__);
 			ret = -EINVAL;
 			break;
 		}