ice: Register auxiliary device to provide RDMA

Register ice client auxiliary RDMA device on the auxiliary bus per
PCIe device function for the auxiliary driver (irdma) to attach to.
It allows to realize a single RDMA driver (irdma) capable of working with
multiple netdev drivers over multi-generation Intel HW supporting RDMA.
There is no load ordering dependencies between ice and irdma.

Signed-off-by: Dave Ertman <david.m.ertman@intel.com>
Signed-off-by: Shiraz Saleem <shiraz.saleem@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>

drivers/net/ethernet/intel/Kconfig

@@ -294,6 +294,7 @@ config ICE
 	tristate "Intel(R) Ethernet Connection E800 Series Support"
 	default n
 	depends on PCI_MSI
+	select AUXILIARY_BUS
 	select DIMLIB
 	select NET_DEVLINK
 	select PLDMFW

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

@@ -34,6 +34,7 @@
 #include <linux/if_bridge.h>
 #include <linux/ctype.h>
 #include <linux/bpf.h>
+#include <linux/auxiliary_bus.h>
 #include <linux/avf/virtchnl.h>
 #include <linux/cpu_rmap.h>
 #include <linux/dim.h>
@@ -647,6 +648,8 @@ int ice_get_rss_key(struct ice_vsi *vsi, u8 *seed);
 void ice_fill_rss_lut(u8 *lut, u16 rss_table_size, u16 rss_size);
 int ice_schedule_reset(struct ice_pf *pf, enum ice_reset_req reset);
 void ice_print_link_msg(struct ice_vsi *vsi, bool isup);
+int ice_plug_aux_dev(struct ice_pf *pf);
+void ice_unplug_aux_dev(struct ice_pf *pf);
 int ice_init_rdma(struct ice_pf *pf);
 const char *ice_stat_str(enum ice_status stat_err);
 const char *ice_aq_str(enum ice_aq_err aq_err);
@@ -678,8 +681,10 @@ void ice_service_task_schedule(struct ice_pf *pf);
  */
 static inline void ice_set_rdma_cap(struct ice_pf *pf)
 {
-	if (pf->hw.func_caps.common_cap.rdma && pf->num_rdma_msix)
+	if (pf->hw.func_caps.common_cap.rdma && pf->num_rdma_msix) {
 		set_bit(ICE_FLAG_RDMA_ENA, pf->flags);
+		ice_plug_aux_dev(pf);
+	}
 }
 
 /**
@@ -688,6 +693,7 @@ static inline void ice_set_rdma_cap(struct ice_pf *pf)
  */
 static inline void ice_clear_rdma_cap(struct ice_pf *pf)
 {
+	ice_unplug_aux_dev(pf);
 	clear_bit(ICE_FLAG_RDMA_ENA, pf->flags);
 }
 #endif /* _ICE_H_ */

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

@@ -249,6 +249,71 @@ static int ice_reserve_rdma_qvector(struct ice_pf *pf)
 	return 0;
 }
 
+/**
+ * ice_adev_release - function to be mapped to AUX dev's release op
+ * @dev: pointer to device to free
+ */
+static void ice_adev_release(struct device *dev)
+{
+	struct iidc_auxiliary_dev *iadev;
+
+	iadev = container_of(dev, struct iidc_auxiliary_dev, adev.dev);
+	kfree(iadev);
+}
+
+/**
+ * ice_plug_aux_dev - allocate and register AUX device
+ * @pf: pointer to pf struct
+ */
+int ice_plug_aux_dev(struct ice_pf *pf)
+{
+	struct iidc_auxiliary_dev *iadev;
+	struct auxiliary_device *adev;
+	int ret;
+
+	iadev = kzalloc(sizeof(*iadev), GFP_KERNEL);
+	if (!iadev)
+		return -ENOMEM;
+
+	adev = &iadev->adev;
+	pf->adev = adev;
+	iadev->pf = pf;
+
+	adev->id = pf->aux_idx;
+	adev->dev.release = ice_adev_release;
+	adev->dev.parent = &pf->pdev->dev;
+	adev->name = IIDC_RDMA_ROCE_NAME;
+
+	ret = auxiliary_device_init(adev);
+	if (ret) {
+		pf->adev = NULL;
+		kfree(iadev);
+		return ret;
+	}
+
+	ret = auxiliary_device_add(adev);
+	if (ret) {
+		pf->adev = NULL;
+		auxiliary_device_uninit(adev);
+		return ret;
+	}
+
+	return 0;
+}
+
+/* ice_unplug_aux_dev - unregister and free AUX device
+ * @pf: pointer to pf struct
+ */
+void ice_unplug_aux_dev(struct ice_pf *pf)
+{
+	if (!pf->adev)
+		return;
+
+	auxiliary_device_delete(pf->adev);
+	auxiliary_device_uninit(pf->adev);
+	pf->adev = NULL;
+}
+
 /**
  * ice_init_rdma - initializes PF for RDMA use
  * @pf: ptr to ice_pf
@@ -260,8 +325,10 @@ int ice_init_rdma(struct ice_pf *pf)
 
 	/* Reserve vector resources */
 	ret = ice_reserve_rdma_qvector(pf);
-	if (ret < 0)
+	if (ret < 0) {
 		dev_err(dev, "failed to reserve vectors for RDMA\n");
+		return ret;
+	}
 
-	return ret;
+	return ice_plug_aux_dev(pf);
 }

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

@@ -456,6 +456,8 @@ ice_prepare_for_reset(struct ice_pf *pf)
 	if (test_bit(ICE_PREPARED_FOR_RESET, pf->state))
 		return;
 
+	ice_unplug_aux_dev(pf);
+
 	/* Notify VFs of impending reset */
 	if (ice_check_sq_alive(hw, &hw->mailboxq))
 		ice_vc_notify_reset(pf);