net: thunderx: Fix IOMMU translation faults

ACPI support has been added to ARM IOMMU driver in 4.10 kernel
and that has resulted in VNIC interfaces throwing translation
faults when kernel is booted with ACPI as driver was not using
DMA API. This patch fixes the issue by using DMA API which inturn
will create translation tables when IOMMU is enabled.

Also VNIC doesn't have a seperate receive buffer ring per receive
queue, so there is no 1:1 descriptor index matching between CQE_RX
and the index in buffer ring from where a buffer has been used for
DMA'ing. Unlike other NICs, here it's not possible to maintain dma
address to virt address mappings within the driver. This leaves us
no other choice but to use IOMMU's IOVA address conversion API to
get buffer's virtual address which can be given to network stack
for processing.

Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_main.c b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
index 6feaa24bcfd4..24017588f531 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_main.c
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_main.c
@@ -16,6 +16,7 @@
 #include <linux/log2.h>
 #include <linux/prefetch.h>
 #include <linux/irq.h>
+#include <linux/iommu.h>
 
 #include "nic_reg.h"
 #include "nic.h"
@@ -525,7 +526,12 @@ static void nicvf_snd_pkt_handler(struct net_device *netdev,
 			/* Get actual TSO descriptors and free them */
 			tso_sqe =
 			 (struct sq_hdr_subdesc *)GET_SQ_DESC(sq, hdr->rsvd2);
+			nicvf_unmap_sndq_buffers(nic, sq, hdr->rsvd2,
+						 tso_sqe->subdesc_cnt);
 			nicvf_put_sq_desc(sq, tso_sqe->subdesc_cnt + 1);
+		} else {
+			nicvf_unmap_sndq_buffers(nic, sq, cqe_tx->sqe_ptr,
+						 hdr->subdesc_cnt);
 		}
 		nicvf_put_sq_desc(sq, hdr->subdesc_cnt + 1);
 		prefetch(skb);
@@ -576,6 +582,7 @@ static void nicvf_rcv_pkt_handler(struct net_device *netdev,
 {
 	struct sk_buff *skb;
 	struct nicvf *nic = netdev_priv(netdev);
+	struct nicvf *snic = nic;
 	int err = 0;
 	int rq_idx;
 
@@ -592,7 +599,7 @@ static void nicvf_rcv_pkt_handler(struct net_device *netdev,
 	if (err && !cqe_rx->rb_cnt)
 		return;
 
-	skb = nicvf_get_rcv_skb(nic, cqe_rx);
+	skb = nicvf_get_rcv_skb(snic, cqe_rx);
 	if (!skb) {
 		netdev_dbg(nic->netdev, "Packet not received\n");
 		return;
@@ -1643,6 +1650,9 @@ static int nicvf_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (!pass1_silicon(nic->pdev))
 		nic->hw_tso = true;
 
+	/* Get iommu domain for iova to physical addr conversion */
+	nic->iommu_domain = iommu_get_domain_for_dev(dev);
+
 	pci_read_config_word(nic->pdev, PCI_SUBSYSTEM_ID, &sdevid);
 	if (sdevid == 0xA134)
 		nic->t88 = true;