[PATCH 14/15] habanalabs/gaudi: support DCB protocol

[Oded Gabbay <oded.gabbay@gmail.com>]

From: Omer Shpigelman <oshpigelman@habana.ai>

Add DCB support to configure the NIC's Priority Flow Control (PFC).
The added support is minimal because a full support is not
currently required.

A summary of the supported callbacks:

- ieee_getpfc: get the current PFC configuration. PFC is enabled by
               default.
- ieee_setpfc: set PFC configuration. Only 0 or all 4 priorities can be
               enabled, no subset is allowed.
- getdcbx: get DCBX capability.
- setdcbx: set DCBX capability. Only host LLDP agent and IEEE protocol
           flavors are supported.

Signed-off-by: Omer Shpigelman <oshpigelman@habana.ai>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
---
 drivers/misc/habanalabs/gaudi/Makefile        |   2 +-
 drivers/misc/habanalabs/gaudi/gaudi_nic.c     |   3 +
 .../misc/habanalabs/gaudi/gaudi_nic_dcbnl.c   | 108 ++++++++++++++++++
 3 files changed, 112 insertions(+), 1 deletion(-)
 create mode 100644 drivers/misc/habanalabs/gaudi/gaudi_nic_dcbnl.c

diff --git a/drivers/misc/habanalabs/gaudi/Makefile b/drivers/misc/habanalabs/gaudi/Makefile
index e3002dc34a74..9757c8ba1cb0 100644
--- a/drivers/misc/habanalabs/gaudi/Makefile
+++ b/drivers/misc/habanalabs/gaudi/Makefile
@@ -3,5 +3,5 @@ HL_GAUDI_FILES := gaudi/gaudi.o gaudi/gaudi_hwmgr.o gaudi/gaudi_security.o \
 	gaudi/gaudi_coresight.o
 
 HL_GAUDI_FILES += gaudi/gaudi_nic.o gaudi/gaudi_phy.o \
-	gaudi/gaudi_nic_ethtool.o \
+	gaudi/gaudi_nic_ethtool.o gaudi/gaudi_nic_dcbnl.o \
 	gaudi/gaudi_nic_debugfs.o
diff --git a/drivers/misc/habanalabs/gaudi/gaudi_nic.c b/drivers/misc/habanalabs/gaudi/gaudi_nic.c
index 108db990efa8..1ea410cdafdf 100644
--- a/drivers/misc/habanalabs/gaudi/gaudi_nic.c
+++ b/drivers/misc/habanalabs/gaudi/gaudi_nic.c
@@ -2745,6 +2745,9 @@ static int port_register(struct hl_device *hdev, int port)
 
 	ndev->netdev_ops = &gaudi_nic_netdev_ops;
 	ndev->ethtool_ops = &gaudi_nic_ethtool_ops;
+#ifdef CONFIG_DCB
+	ndev->dcbnl_ops = &gaudi_nic_dcbnl_ops;
+#endif
 	ndev->watchdog_timeo = NIC_TX_TIMEOUT;
 	ndev->min_mtu = ETH_MIN_MTU;
 	ndev->max_mtu = NIC_MAX_MTU;
diff --git a/drivers/misc/habanalabs/gaudi/gaudi_nic_dcbnl.c b/drivers/misc/habanalabs/gaudi/gaudi_nic_dcbnl.c
new file mode 100644
index 000000000000..b8f37fd0d3cf
--- /dev/null
+++ b/drivers/misc/habanalabs/gaudi/gaudi_nic_dcbnl.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * Copyright 2018-2020 HabanaLabs, Ltd.
+ * All Rights Reserved.
+ */
+
+#include "gaudi_nic.h"
+
+#define PFC_PRIO_NUM		4
+#define PFC_PRIO_MASK_ALL	GENMASK(PFC_PRIO_NUM - 1, 0)
+#define PFC_PRIO_MASK_NONE	0
+#define PFC_STAT_TX_OFFSET	17
+#define PFC_STAT_RX_OFFSET	27
+
+#ifdef CONFIG_DCB
+static int gaudi_nic_dcbnl_ieee_getpfc(struct net_device *netdev,
+					struct ieee_pfc *pfc)
+{
+	struct gaudi_nic_device **ptr = netdev_priv(netdev);
+	struct gaudi_nic_device *gaudi_nic = *ptr;
+	struct hl_device *hdev = gaudi_nic->hdev;
+	u32 port = gaudi_nic->port;
+	int rc = 0, i, tx_idx, rx_idx;
+
+	if (disabled_or_in_reset(gaudi_nic)) {
+		dev_info_ratelimited(hdev->dev,
+				"port %d is in reset, can't get PFC", port);
+		return -EBUSY;
+	}
+
+	pfc->pfc_en = gaudi_nic->pfc_enable ? PFC_PRIO_MASK_ALL :
+							PFC_PRIO_MASK_NONE;
+	pfc->pfc_cap = PFC_PRIO_NUM;
+
+	for (i = 0 ; i < PFC_PRIO_NUM ; i++) {
+		tx_idx = PFC_STAT_TX_OFFSET + i;
+		rx_idx = PFC_STAT_RX_OFFSET + i;
+
+		pfc->requests[i] = gaudi_nic_read_mac_stat_counter(hdev, port,
+								tx_idx, false);
+		pfc->indications[i] = gaudi_nic_read_mac_stat_counter(hdev,
+							port, rx_idx, true);
+	}
+
+	return rc;
+}
+
+static int gaudi_nic_dcbnl_ieee_setpfc(struct net_device *netdev,
+					struct ieee_pfc *pfc)
+{
+	struct gaudi_nic_device **ptr = netdev_priv(netdev);
+	struct gaudi_nic_device *gaudi_nic = *ptr;
+	struct hl_device *hdev = gaudi_nic->hdev;
+	u32 port = gaudi_nic->port;
+	u8 curr_pfc_en;
+
+	if (pfc->pfc_en & ~PFC_PRIO_MASK_ALL) {
+		dev_info_ratelimited(hdev->dev,
+					"PFC supports %d priorities only, port %d\n",
+					PFC_PRIO_NUM, port);
+		return -EINVAL;
+	}
+
+	if ((pfc->pfc_en != PFC_PRIO_MASK_NONE) &&
+			(pfc->pfc_en != PFC_PRIO_MASK_ALL)) {
+		dev_info_ratelimited(hdev->dev,
+					"PFC should be enabled/disabled on all priorities, port %d\n",
+					port);
+		return -EINVAL;
+	}
+
+	if (disabled_or_in_reset(gaudi_nic)) {
+		dev_info_ratelimited(hdev->dev,
+				"port %d is in reset, can't set PFC", port);
+		return -EBUSY;
+	}
+
+	curr_pfc_en = gaudi_nic->pfc_enable ? PFC_PRIO_MASK_ALL :
+							PFC_PRIO_MASK_NONE;
+
+	if (pfc->pfc_en == curr_pfc_en)
+		return 0;
+
+	gaudi_nic->pfc_enable = !gaudi_nic->pfc_enable;
+
+	gaudi_nic_set_pfc(gaudi_nic);
+
+	return 0;
+}
+
+static u8 gaudi_nic_dcbnl_getdcbx(struct net_device *netdev)
+{
+	return DCB_CAP_DCBX_HOST | DCB_CAP_DCBX_VER_IEEE;
+}
+
+static u8 gaudi_nic_dcbnl_setdcbx(struct net_device *netdev, u8 mode)
+{
+	return !(mode == (DCB_CAP_DCBX_HOST | DCB_CAP_DCBX_VER_IEEE));
+}
+
+const struct dcbnl_rtnl_ops gaudi_nic_dcbnl_ops = {
+	.ieee_getpfc	= gaudi_nic_dcbnl_ieee_getpfc,
+	.ieee_setpfc	= gaudi_nic_dcbnl_ieee_setpfc,
+	.getdcbx	= gaudi_nic_dcbnl_getdcbx,
+	.setdcbx	= gaudi_nic_dcbnl_setdcbx
+};
+#endif
-- 
2.17.1