pds_vdpa: Add new vDPA driver for AMD/Pensando DSC

This is the initial auxiliary driver framework for a new vDPA
device driver, an auxiliary_bus client of the pds_core driver.
The pds_core driver supplies the PCI services for the VF device
and for accessing the adminq in the PF device.

This patch adds the very basics of registering for the auxiliary
device and setting up debugfs entries.

Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20230519215632.12343-4-shannon.nelson@amd.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

drivers/vdpa/Makefile

@@ -7,3 +7,4 @@ obj-$(CONFIG_MLX5_VDPA) += mlx5/
 obj-$(CONFIG_VP_VDPA)    += virtio_pci/
 obj-$(CONFIG_ALIBABA_ENI_VDPA) += alibaba/
 obj-$(CONFIG_SNET_VDPA) += solidrun/
+obj-$(CONFIG_PDS_VDPA) += pds/

drivers/vdpa/pds/Makefile

@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# Copyright(c) 2023 Advanced Micro Devices, Inc
+
+obj-$(CONFIG_PDS_VDPA) := pds_vdpa.o
+
+pds_vdpa-y := aux_drv.o
+
+pds_vdpa-$(CONFIG_DEBUG_FS) += debugfs.o

drivers/vdpa/pds/aux_drv.c

@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2023 Advanced Micro Devices, Inc */
+
+#include <linux/auxiliary_bus.h>
+#include <linux/pci.h>
+
+#include <linux/pds/pds_common.h>
+#include <linux/pds/pds_core_if.h>
+#include <linux/pds/pds_adminq.h>
+#include <linux/pds/pds_auxbus.h>
+
+#include "aux_drv.h"
+#include "debugfs.h"
+
+static const struct auxiliary_device_id pds_vdpa_id_table[] = {
+	{ .name = PDS_VDPA_DEV_NAME, },
+	{},
+};
+
+static int pds_vdpa_probe(struct auxiliary_device *aux_dev,
+			  const struct auxiliary_device_id *id)
+
+{
+	struct pds_auxiliary_dev *padev =
+		container_of(aux_dev, struct pds_auxiliary_dev, aux_dev);
+	struct pds_vdpa_aux *vdpa_aux;
+
+	vdpa_aux = kzalloc(sizeof(*vdpa_aux), GFP_KERNEL);
+	if (!vdpa_aux)
+		return -ENOMEM;
+
+	vdpa_aux->padev = padev;
+	auxiliary_set_drvdata(aux_dev, vdpa_aux);
+
+	return 0;
+}
+
+static void pds_vdpa_remove(struct auxiliary_device *aux_dev)
+{
+	struct pds_vdpa_aux *vdpa_aux = auxiliary_get_drvdata(aux_dev);
+	struct device *dev = &aux_dev->dev;
+
+	kfree(vdpa_aux);
+	auxiliary_set_drvdata(aux_dev, NULL);
+
+	dev_info(dev, "Removed\n");
+}
+
+static struct auxiliary_driver pds_vdpa_driver = {
+	.name = PDS_DEV_TYPE_VDPA_STR,
+	.probe = pds_vdpa_probe,
+	.remove = pds_vdpa_remove,
+	.id_table = pds_vdpa_id_table,
+};
+
+static void __exit pds_vdpa_cleanup(void)
+{
+	auxiliary_driver_unregister(&pds_vdpa_driver);
+
+	pds_vdpa_debugfs_destroy();
+}
+module_exit(pds_vdpa_cleanup);
+
+static int __init pds_vdpa_init(void)
+{
+	int err;
+
+	pds_vdpa_debugfs_create();
+
+	err = auxiliary_driver_register(&pds_vdpa_driver);
+	if (err) {
+		pr_err("%s: aux driver register failed: %pe\n",
+		       PDS_VDPA_DRV_NAME, ERR_PTR(err));
+		pds_vdpa_debugfs_destroy();
+	}
+
+	return err;
+}
+module_init(pds_vdpa_init);
+
+MODULE_DESCRIPTION(PDS_VDPA_DRV_DESCRIPTION);
+MODULE_AUTHOR("Advanced Micro Devices, Inc");
+MODULE_LICENSE("GPL");

drivers/vdpa/pds/aux_drv.h

@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright(c) 2023 Advanced Micro Devices, Inc */
+
+#ifndef _AUX_DRV_H_
+#define _AUX_DRV_H_
+
+#define PDS_VDPA_DRV_DESCRIPTION    "AMD/Pensando vDPA VF Device Driver"
+#define PDS_VDPA_DRV_NAME           KBUILD_MODNAME
+
+struct pds_vdpa_aux {
+	struct pds_auxiliary_dev *padev;
+
+	struct dentry *dentry;
+};
+#endif /* _AUX_DRV_H_ */

drivers/vdpa/pds/debugfs.c

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2023 Advanced Micro Devices, Inc */
+
+#include <linux/pci.h>
+
+#include <linux/pds/pds_common.h>
+#include <linux/pds/pds_core_if.h>
+#include <linux/pds/pds_adminq.h>
+#include <linux/pds/pds_auxbus.h>
+
+#include "aux_drv.h"
+#include "debugfs.h"
+
+static struct dentry *dbfs_dir;
+
+void pds_vdpa_debugfs_create(void)
+{
+	dbfs_dir = debugfs_create_dir(PDS_VDPA_DRV_NAME, NULL);
+}
+
+void pds_vdpa_debugfs_destroy(void)
+{
+	debugfs_remove_recursive(dbfs_dir);
+	dbfs_dir = NULL;
+}

drivers/vdpa/pds/debugfs.h

@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright(c) 2023 Advanced Micro Devices, Inc */
+
+#ifndef _PDS_VDPA_DEBUGFS_H_
+#define _PDS_VDPA_DEBUGFS_H_
+
+#include <linux/debugfs.h>
+
+void pds_vdpa_debugfs_create(void);
+void pds_vdpa_debugfs_destroy(void);
+
+#endif /* _PDS_VDPA_DEBUGFS_H_ */

include/linux/pds/pds_common.h

@@ -39,6 +39,8 @@ enum pds_core_vif_types {
 #define PDS_DEV_TYPE_RDMA_STR	"RDMA"
 #define PDS_DEV_TYPE_LM_STR	"LM"
 
+#define PDS_VDPA_DEV_NAME	PDS_CORE_DRV_NAME "." PDS_DEV_TYPE_VDPA_STR
+
 #define PDS_CORE_IFNAMSIZ		16
 
 /**