RDMA/bnxt_re: Enable atomics only if host bios supports

Driver shall check if the host system bios has enabled
Atomic operations capability in PCI Device Control 2
register of the pci-device. Expose the ATOMIC_HCA
flag only if the Atomic operations capability is set.

Signed-off-by: Devesh Sharma <devesh.sharma@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/drivers/infiniband/hw/bnxt_re/qplib_sp.c b/drivers/infiniband/hw/bnxt_re/qplib_sp.c
index 5827573..ef91ab7 100644
--- a/drivers/infiniband/hw/bnxt_re/qplib_sp.c
+++ b/drivers/infiniband/hw/bnxt_re/qplib_sp.c
@@ -51,6 +51,19 @@ const struct bnxt_qplib_gid bnxt_qplib_gid_zero = {{ 0, 0, 0, 0, 0, 0, 0, 0,
 						     0, 0, 0, 0, 0, 0, 0, 0 } };
 
 /* Device */
+
+static bool bnxt_qplib_is_atomic_cap(struct bnxt_qplib_rcfw *rcfw)
+{
+	int rc;
+	u16 pcie_ctl2;
+
+	rc = pcie_capability_read_word(rcfw->pdev, PCI_EXP_DEVCTL2,
+				       &pcie_ctl2);
+	if (rc)
+		return false;
+	return !!(pcie_ctl2 & PCI_EXP_DEVCTL2_ATOMIC_REQ);
+}
+
 int bnxt_qplib_get_dev_attr(struct bnxt_qplib_rcfw *rcfw,
 			    struct bnxt_qplib_dev_attr *attr)
 {
@@ -131,6 +144,7 @@ int bnxt_qplib_get_dev_attr(struct bnxt_qplib_rcfw *rcfw,
 		attr->tqm_alloc_reqs[i * 4 + 3] = *(++tqm_alloc);
 	}
 
+	attr->is_atomic = bnxt_qplib_is_atomic_cap(rcfw);
 bail:
 	bnxt_qplib_rcfw_free_sbuf(rcfw, sbuf);
 	return rc;