qed: VFs to try utilizing the doorbell bar

VFs are currently not mapping their doorbell bar, instead relying
on the small doorbell window they have in their limited regview bar.

In order to increase the number of possible Tx connections [queues]
employeed by VF past 16, we need to start using the doorbell bar if
one such is exposed - VF would communicate this fact to PF which would
return the size-bar internally configured into chip, according to
which the VF would decide whether to actually utilize the doorbell
bar.

Signed-off-by: Yuval Mintz <Yuval.Mintz@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 58 insertions, 3 deletions

diff --git a/drivers/net/ethernet/qlogic/qed/qed_sriov.c b/drivers/net/ethernet/qlogic/qed/qed_sriov.c
index c620a5fa250b..e39ad22947cf 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_sriov.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_sriov.c
@@ -1384,6 +1384,60 @@ static void qed_iov_vf_cleanup(struct qed_hwfn *p_hwfn,
 	qed_iov_clean_vf(p_hwfn, p_vf->relative_vf_id);
 }
 
+/* Returns either 0, or log(size) */
+static u32 qed_iov_vf_db_bar_size(struct qed_hwfn *p_hwfn,
+				  struct qed_ptt *p_ptt)
+{
+	u32 val = qed_rd(p_hwfn, p_ptt, PGLUE_B_REG_VF_BAR1_SIZE);
+
+	if (val)
+		return val + 11;
+	return 0;
+}
+
+static void
+qed_iov_vf_mbx_acquire_resc_cids(struct qed_hwfn *p_hwfn,
+				 struct qed_ptt *p_ptt,
+				 struct qed_vf_info *p_vf,
+				 struct vf_pf_resc_request *p_req,
+				 struct pf_vf_resc *p_resp)
+{
+	u8 num_vf_cons = p_hwfn->pf_params.eth_pf_params.num_vf_cons;
+	u8 db_size = qed_db_addr_vf(1, DQ_DEMS_LEGACY) -
+		     qed_db_addr_vf(0, DQ_DEMS_LEGACY);
+	u32 bar_size;
+
+	p_resp->num_cids = min_t(u8, p_req->num_cids, num_vf_cons);
+
+	/* If VF didn't bother asking for QIDs than don't bother limiting
+	 * number of CIDs. The VF doesn't care about the number, and this
+	 * has the likely result of causing an additional acquisition.
+	 */
+	if (!(p_vf->acquire.vfdev_info.capabilities &
+	      VFPF_ACQUIRE_CAP_QUEUE_QIDS))
+		return;
+
+	/* If doorbell bar was mapped by VF, limit the VF CIDs to an amount
+	 * that would make sure doorbells for all CIDs fall within the bar.
+	 * If it doesn't, make sure regview window is sufficient.
+	 */
+	if (p_vf->acquire.vfdev_info.capabilities &
+	    VFPF_ACQUIRE_CAP_PHYSICAL_BAR) {
+		bar_size = qed_iov_vf_db_bar_size(p_hwfn, p_ptt);
+		if (bar_size)
+			bar_size = 1 << bar_size;
+
+		if (p_hwfn->cdev->num_hwfns > 1)
+			bar_size /= 2;
+	} else {
+		bar_size = PXP_VF_BAR0_DQ_LENGTH;
+	}
+
+	if (bar_size / db_size < 256)
+		p_resp->num_cids = min_t(u8, p_resp->num_cids,
+					 (u8)(bar_size / db_size));
+}
+
 static u8 qed_iov_vf_mbx_acquire_resc(struct qed_hwfn *p_hwfn,
 				      struct qed_ptt *p_ptt,
 				      struct qed_vf_info *p_vf,
@@ -1417,9 +1471,7 @@ static u8 qed_iov_vf_mbx_acquire_resc(struct qed_hwfn *p_hwfn,
 	p_resp->num_vlan_filters = min_t(u8, p_vf->num_vlan_filters,
 					 p_req->num_vlan_filters);
 
-	p_resp->num_cids =
-	    min_t(u8, p_req->num_cids,
-		  p_hwfn->pf_params.eth_pf_params.num_vf_cons);
+	qed_iov_vf_mbx_acquire_resc_cids(p_hwfn, p_ptt, p_vf, p_req, p_resp);
 
 	/* This isn't really needed/enforced, but some legacy VFs might depend
 	 * on the correct filling of this field.
@@ -1572,6 +1624,9 @@ static void qed_iov_vf_mbx_acquire(struct qed_hwfn *p_hwfn,
 	if (req->vfdev_info.capabilities & VFPF_ACQUIRE_CAP_QUEUE_QIDS)
 		pfdev_info->capabilities |= PFVF_ACQUIRE_CAP_QUEUE_QIDS;
 
+	/* Share the sizes of the bars with VF */
+	resp->pfdev_info.bar_size = qed_iov_vf_db_bar_size(p_hwfn, p_ptt);
+
 	qed_iov_vf_mbx_acquire_stats(p_hwfn, &pfdev_info->stats_info);
 
 	memcpy(pfdev_info->port_mac, p_hwfn->hw_info.hw_mac_addr, ETH_ALEN);