net: ionic: Create an auxiliary device for rdma driver

To support RDMA capable ethernet device, create an auxiliary device in
the ionic Ethernet driver. The RDMA device is modeled as an auxiliary
device to the Ethernet device.

Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
Signed-off-by: Abhijit Gangurde <abhijit.gangurde@amd.com>
Link: https://patch.msgid.link/20250903061606.4139957-2-abhijit.gangurde@amd.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>

8 files changed, 128 insertions, 1 deletions

diff --git a/drivers/net/ethernet/pensando/Kconfig b/drivers/net/ethernet/pensando/Kconfig
index 01fe76786f77..c99758adf3ad 100644
--- a/drivers/net/ethernet/pensando/Kconfig
+++ b/drivers/net/ethernet/pensando/Kconfig
@@ -24,6 +24,7 @@ config IONIC
 	select NET_DEVLINK
 	select DIMLIB
 	select PAGE_POOL
+	select AUXILIARY_BUS
 	help
 	  This enables the support for the Pensando family of Ethernet
 	  adapters.  More specific information on this driver can be
diff --git a/drivers/net/ethernet/pensando/ionic/Makefile b/drivers/net/ethernet/pensando/ionic/Makefile
index 4e7642a2d25f..a598972fef41 100644
--- a/drivers/net/ethernet/pensando/ionic/Makefile
+++ b/drivers/net/ethernet/pensando/ionic/Makefile
@@ -5,5 +5,5 @@ obj-$(CONFIG_IONIC) := ionic.o
 
 ionic-y := ionic_main.o ionic_bus_pci.o ionic_devlink.o ionic_dev.o \
 	   ionic_debugfs.o ionic_lif.o ionic_rx_filter.o ionic_ethtool.o \
-	   ionic_txrx.o ionic_stats.o ionic_fw.o
+	   ionic_txrx.o ionic_stats.o ionic_fw.o ionic_aux.o
 ionic-$(CONFIG_PTP_1588_CLOCK) += ionic_phc.o
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_api.h b/drivers/net/ethernet/pensando/ionic/ionic_api.h
new file mode 100644
index 000000000000..f9fcd1b67b35
--- /dev/null
+++ b/drivers/net/ethernet/pensando/ionic/ionic_api.h
@@ -0,0 +1,21 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2018-2025, Advanced Micro Devices, Inc. */
+
+#ifndef _IONIC_API_H_
+#define _IONIC_API_H_
+
+#include <linux/auxiliary_bus.h>
+
+/**
+ * struct ionic_aux_dev - Auxiliary device information
+ * @lif:        Logical interface
+ * @idx:        Index identifier
+ * @adev:       Auxiliary device
+ */
+struct ionic_aux_dev {
+	struct ionic_lif *lif;
+	int idx;
+	struct auxiliary_device adev;
+};
+
+#endif /* _IONIC_API_H_ */
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_aux.c b/drivers/net/ethernet/pensando/ionic/ionic_aux.c
new file mode 100644
index 000000000000..f3c2a5227b36
--- /dev/null
+++ b/drivers/net/ethernet/pensando/ionic/ionic_aux.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2018-2025, Advanced Micro Devices, Inc. */
+
+#include <linux/kernel.h>
+#include "ionic.h"
+#include "ionic_lif.h"
+#include "ionic_aux.h"
+
+static DEFINE_IDA(aux_ida);
+
+static void ionic_auxbus_release(struct device *dev)
+{
+	struct ionic_aux_dev *ionic_adev;
+
+	ionic_adev = container_of(dev, struct ionic_aux_dev, adev.dev);
+	ida_free(&aux_ida, ionic_adev->adev.id);
+	kfree(ionic_adev);
+}
+
+int ionic_auxbus_register(struct ionic_lif *lif)
+{
+	struct ionic_aux_dev *ionic_adev;
+	struct auxiliary_device *aux_dev;
+	int err, id;
+
+	if (!(le64_to_cpu(lif->ionic->ident.lif.capabilities) & IONIC_LIF_CAP_RDMA))
+		return 0;
+
+	ionic_adev = kzalloc(sizeof(*ionic_adev), GFP_KERNEL);
+	if (!ionic_adev)
+		return -ENOMEM;
+
+	aux_dev = &ionic_adev->adev;
+
+	id = ida_alloc(&aux_ida, GFP_KERNEL);
+	if (id < 0) {
+		dev_err(lif->ionic->dev, "Failed to allocate aux id: %d\n", id);
+		kfree(ionic_adev);
+		return id;
+	}
+
+	aux_dev->id = id;
+	aux_dev->name = "rdma";
+	aux_dev->dev.parent = &lif->ionic->pdev->dev;
+	aux_dev->dev.release = ionic_auxbus_release;
+	ionic_adev->lif = lif;
+	err = auxiliary_device_init(aux_dev);
+	if (err) {
+		dev_err(lif->ionic->dev, "Failed to initialize %s aux device: %d\n",
+			aux_dev->name, err);
+		ida_free(&aux_ida, id);
+		kfree(ionic_adev);
+		return err;
+	}
+
+	err = auxiliary_device_add(aux_dev);
+	if (err) {
+		dev_err(lif->ionic->dev, "Failed to add %s aux device: %d\n",
+			aux_dev->name, err);
+		auxiliary_device_uninit(aux_dev);
+		return err;
+	}
+
+	lif->ionic_adev = ionic_adev;
+	return 0;
+}
+
+void ionic_auxbus_unregister(struct ionic_lif *lif)
+{
+	mutex_lock(&lif->adev_lock);
+	if (!lif->ionic_adev)
+		goto out;
+
+	auxiliary_device_delete(&lif->ionic_adev->adev);
+	auxiliary_device_uninit(&lif->ionic_adev->adev);
+
+	lif->ionic_adev = NULL;
+out:
+	mutex_unlock(&lif->adev_lock);
+}
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_aux.h b/drivers/net/ethernet/pensando/ionic/ionic_aux.h
new file mode 100644
index 000000000000..f5528a9f187d
--- /dev/null
+++ b/drivers/net/ethernet/pensando/ionic/ionic_aux.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (C) 2018-2025, Advanced Micro Devices, Inc. */
+
+#ifndef _IONIC_AUX_H_
+#define _IONIC_AUX_H_
+
+int ionic_auxbus_register(struct ionic_lif *lif);
+void ionic_auxbus_unregister(struct ionic_lif *lif);
+
+#endif /* _IONIC_AUX_H_ */
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c b/drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c
index 136bfa3516d0..f8752b1d2790 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_bus_pci.c
@@ -9,6 +9,7 @@
 #include "ionic.h"
 #include "ionic_bus.h"
 #include "ionic_lif.h"
+#include "ionic_aux.h"
 #include "ionic_debugfs.h"
 
 /* Supported devices */
@@ -375,6 +376,8 @@ static int ionic_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto err_out_deregister_devlink;
 	}
 
+	ionic_auxbus_register(ionic->lif);
+
 	mod_timer(&ionic->watchdog_timer,
 		  round_jiffies(jiffies + ionic->watchdog_period));
 	ionic_queue_doorbell_check(ionic, IONIC_NAPI_DEADLINE);
@@ -416,6 +419,7 @@ static void ionic_remove(struct pci_dev *pdev)
 
 		if (ionic->lif->doorbell_wa)
 			cancel_delayed_work_sync(&ionic->doorbell_check_dwork);
+		ionic_auxbus_unregister(ionic->lif);
 		ionic_lif_unregister(ionic->lif);
 		ionic_devlink_unregister(ionic);
 		ionic_lif_deinit(ionic->lif);
@@ -445,6 +449,7 @@ static void ionic_reset_prepare(struct pci_dev *pdev)
 	timer_delete_sync(&ionic->watchdog_timer);
 	cancel_work_sync(&lif->deferred.work);
 
+	ionic_auxbus_unregister(ionic->lif);
 	mutex_lock(&lif->queue_lock);
 	ionic_stop_queues_reconfig(lif);
 	ionic_txrx_free(lif);
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_lif.c b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
index 48cb5d30b5f6..8ed5d2e5fde4 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_lif.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
@@ -19,6 +19,7 @@
 #include "ionic_bus.h"
 #include "ionic_dev.h"
 #include "ionic_lif.h"
+#include "ionic_aux.h"
 #include "ionic_txrx.h"
 #include "ionic_ethtool.h"
 #include "ionic_debugfs.h"
@@ -3293,6 +3294,7 @@ int ionic_lif_alloc(struct ionic *ionic)
 
 	mutex_init(&lif->queue_lock);
 	mutex_init(&lif->config_lock);
+	mutex_init(&lif->adev_lock);
 
 	spin_lock_init(&lif->adminq_lock);
 
@@ -3349,6 +3351,7 @@ err_out_free_lif_info:
 	lif->info = NULL;
 	lif->info_pa = 0;
 err_out_free_mutex:
+	mutex_destroy(&lif->adev_lock);
 	mutex_destroy(&lif->config_lock);
 	mutex_destroy(&lif->queue_lock);
 err_out_free_netdev:
@@ -3384,6 +3387,7 @@ static void ionic_lif_handle_fw_down(struct ionic_lif *lif)
 
 	netif_device_detach(lif->netdev);
 
+	ionic_auxbus_unregister(ionic->lif);
 	mutex_lock(&lif->queue_lock);
 	if (test_bit(IONIC_LIF_F_UP, lif->state)) {
 		dev_info(ionic->dev, "Surprise FW stop, stopping queues\n");
@@ -3446,6 +3450,8 @@ int ionic_restart_lif(struct ionic_lif *lif)
 	netif_device_attach(lif->netdev);
 	ionic_queue_doorbell_check(ionic, IONIC_NAPI_DEADLINE);
 
+	ionic_auxbus_register(ionic->lif);
+
 	return 0;
 
 err_txrx_free:
@@ -3528,6 +3534,7 @@ void ionic_lif_free(struct ionic_lif *lif)
 
 	mutex_destroy(&lif->config_lock);
 	mutex_destroy(&lif->queue_lock);
+	mutex_destroy(&lif->adev_lock);
 
 	/* free netdev & lif */
 	ionic_debugfs_del_lif(lif);
diff --git a/drivers/net/ethernet/pensando/ionic/ionic_lif.h b/drivers/net/ethernet/pensando/ionic/ionic_lif.h
index e01756fb7fdd..43bdd0fb8733 100644
--- a/drivers/net/ethernet/pensando/ionic/ionic_lif.h
+++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.h
@@ -10,6 +10,7 @@
 #include <linux/dim.h>
 #include <linux/pci.h>
 #include "ionic_rx_filter.h"
+#include "ionic_api.h"
 
 #define IONIC_ADMINQ_LENGTH	16	/* must be a power of two */
 #define IONIC_NOTIFYQ_LENGTH	64	/* must be a power of two */
@@ -225,6 +226,8 @@ struct ionic_lif {
 	dma_addr_t info_pa;
 	u32 info_sz;
 	struct ionic_qtype_info qtype_info[IONIC_QTYPE_MAX];
+	struct ionic_aux_dev *ionic_adev;
+	struct mutex adev_lock;	/* lock for aux_dev actions */
 
 	u8 rss_hash_key[IONIC_RSS_HASH_KEY_SIZE];
 	u8 *rss_ind_tbl;