ice: support basic E-Switch mode control

Write set and get eswitch mode functions used by devlink
ops. Use new pf struct member eswitch_mode to track current
eswitch mode in driver.

Changing eswitch mode is only allowed when there are no
VFs created.

Create new file for eswitch related code.

Add config flag ICE_SWITCHDEV to allow user to choose if
switchdev support should be enabled or disabled.

Use case examples:
- show current eswitch mode ('legacy' is the default one)
[root@localhost]# devlink dev eswitch show pci/0000:03:00.1
pci/0000:03:00.1: mode legacy

- move to 'switchdev' mode
[root@localhost]# devlink dev eswitch set pci/0000:03:00.1 mode
switchdev
[root@localhost]# devlink dev eswitch show pci/0000:03:00.1
pci/0000:03:00.1: mode switchdev

- create 2 VFs
[root@localhost]# echo 2 > /sys/class/net/ens4f1/device/sriov_numvfs

- unsuccessful attempt to change eswitch mode while VFs are created
[root@localhost]# devlink dev eswitch set pci/0000:03:00.1 mode legacy
devlink answers: Operation not supported

- destroy VFs
[root@localhost]# echo 0 > /sys/class/net/ens4f1/device/sriov_numvfs

- restore 'legacy' mode
[root@localhost]# devlink dev eswitch set pci/0000:03:00.1 mode legacy
[root@localhost]# devlink dev eswitch show pci/0000:03:00.1
pci/0000:03:00.1: mode legacy

Co-developed-by: Grzegorz Nitka <grzegorz.nitka@intel.com>
Signed-off-by: Grzegorz Nitka <grzegorz.nitka@intel.com>
Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Tested-by: Sandeep Penigalapati <sandeep.penigalapati@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/Kconfig

@@ -313,6 +313,20 @@ config ICE
 	  To compile this driver as a module, choose M here. The module
 	  will be called ice.
 
+config ICE_SWITCHDEV
+	bool "Switchdev Support"
+	default y
+	depends on ICE && NET_SWITCHDEV
+	help
+	  Switchdev support provides internal SRIOV packet steering and switching.
+
+	  To enable it on running kernel use devlink tool:
+	  #devlink dev eswitch set pci/0000:XX:XX.X mode switchdev
+
+	  Say Y here if you want to use Switchdev in the driver.
+
+	  If unsure, say N.
+
 config FM10K
 	tristate "Intel(R) FM10000 Ethernet Switch Host Interface Support"
 	default n

drivers/net/ethernet/intel/ice/Makefile

@@ -33,3 +33,4 @@ ice-$(CONFIG_PTP_1588_CLOCK) += ice_ptp.o ice_ptp_hw.o
 ice-$(CONFIG_DCB) += ice_dcb.o ice_dcb_nl.o ice_dcb_lib.o
 ice-$(CONFIG_RFS_ACCEL) += ice_arfs.o
 ice-$(CONFIG_XDP_SOCKETS) += ice_xsk.o
+ice-$(CONFIG_ICE_SWITCHDEV) += ice_eswitch.o

drivers/net/ethernet/intel/ice/ice.h

@@ -439,6 +439,7 @@ struct ice_pf {
 
 	struct ice_vsi **vsi;		/* VSIs created by the driver */
 	struct ice_sw *first_sw;	/* first switch created by firmware */
+	u16 eswitch_mode;		/* current mode of eswitch */
 	/* Virtchnl/SR-IOV config info */
 	struct ice_vf *vf;
 	u16 num_alloc_vfs;		/* actual number of VFs allocated */

drivers/net/ethernet/intel/ice/ice_devlink.c

@@ -4,6 +4,7 @@
 #include "ice.h"
 #include "ice_lib.h"
 #include "ice_devlink.h"
+#include "ice_eswitch.h"
 #include "ice_fw_update.h"
 
 /* context for devlink info version reporting */
@@ -423,6 +424,8 @@ ice_devlink_flash_update(struct devlink *devlink,
 
 static const struct devlink_ops ice_devlink_ops = {
 	.supported_flash_update_params = DEVLINK_SUPPORT_FLASH_UPDATE_OVERWRITE_MASK,
+	.eswitch_mode_get = ice_eswitch_mode_get,
+	.eswitch_mode_set = ice_eswitch_mode_set,
 	.info_get = ice_devlink_info_get,
 	.flash_update = ice_devlink_flash_update,
 };

drivers/net/ethernet/intel/ice/ice_eswitch.c

@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2019-2021, Intel Corporation. */
+
+#include "ice.h"
+#include "ice_eswitch.h"
+#include "ice_devlink.h"
+
+/**
+ * ice_eswitch_mode_set - set new eswitch mode
+ * @devlink: pointer to devlink structure
+ * @mode: eswitch mode to switch to
+ * @extack: pointer to extack structure
+ */
+int
+ice_eswitch_mode_set(struct devlink *devlink, u16 mode,
+		     struct netlink_ext_ack *extack)
+{
+	struct ice_pf *pf = devlink_priv(devlink);
+
+	if (pf->eswitch_mode == mode)
+		return 0;
+
+	if (pf->num_alloc_vfs) {
+		dev_info(ice_pf_to_dev(pf), "Changing eswitch mode is allowed only if there is no VFs created");
+		NL_SET_ERR_MSG_MOD(extack, "Changing eswitch mode is allowed only if there is no VFs created");
+		return -EOPNOTSUPP;
+	}
+
+	switch (mode) {
+	case DEVLINK_ESWITCH_MODE_LEGACY:
+		dev_info(ice_pf_to_dev(pf), "PF %d changed eswitch mode to legacy",
+			 pf->hw.pf_id);
+		NL_SET_ERR_MSG_MOD(extack, "Changed eswitch mode to legacy");
+		break;
+	case DEVLINK_ESWITCH_MODE_SWITCHDEV:
+	{
+		dev_info(ice_pf_to_dev(pf), "PF %d changed eswitch mode to switchdev",
+			 pf->hw.pf_id);
+		NL_SET_ERR_MSG_MOD(extack, "Changed eswitch mode to switchdev");
+		break;
+	}
+	default:
+		NL_SET_ERR_MSG_MOD(extack, "Unknown eswitch mode");
+		return -EINVAL;
+	}
+
+	pf->eswitch_mode = mode;
+	return 0;
+}
+
+/**
+ * ice_eswitch_mode_get - get current eswitch mode
+ * @devlink: pointer to devlink structure
+ * @mode: output parameter for current eswitch mode
+ */
+int ice_eswitch_mode_get(struct devlink *devlink, u16 *mode)
+{
+	struct ice_pf *pf = devlink_priv(devlink);
+
+	*mode = pf->eswitch_mode;
+	return 0;
+}

drivers/net/ethernet/intel/ice/ice_eswitch.h

@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2019-2021, Intel Corporation. */
+
+#ifndef _ICE_ESWITCH_H_
+#define _ICE_ESWITCH_H_
+
+#include <net/devlink.h>
+
+#ifdef CONFIG_ICE_SWITCHDEV
+int ice_eswitch_mode_get(struct devlink *devlink, u16 *mode);
+int
+ice_eswitch_mode_set(struct devlink *devlink, u16 mode,
+		     struct netlink_ext_ack *extack);
+bool ice_is_eswitch_mode_switchdev(struct ice_pf *pf);
+#else /* CONFIG_ICE_SWITCHDEV */
+static inline int
+ice_eswitch_mode_get(struct devlink *devlink, u16 *mode)
+{
+	return DEVLINK_ESWITCH_MODE_LEGACY;
+}
+
+static inline int
+ice_eswitch_mode_set(struct devlink *devlink, u16 mode,
+		     struct netlink_ext_ack *extack)
+{
+	return -EOPNOTSUPP;
+}
+
+static inline bool
+ice_is_eswitch_mode_switchdev(struct ice_pf *pf)
+{
+	return false;
+}
+#endif /* CONFIG_ICE_SWITCHDEV */
+#endif /* _ICE_ESWITCH_H_ */