Merge branch 'devlink-Add-support-for-region-access'

Alex Vesker says:

====================
devlink: Add support for region access

This is a proposal which will allow access to driver defined address
regions using devlink. Each device can create its supported address
regions and register them. A device which exposes a region will allow
access to it using devlink.

The suggested implementation will allow exposing regions to the user,
reading and dumping snapshots taken from different regions.
A snapshot represents a memory image of a region taken by the driver.

If a device collects a snapshot of an address region it can be later
exposed using devlink region read or dump commands.
This functionality allows for future analyses on the snapshots to be
done.

The major benefit of this support is not only to provide access to
internal address regions which were inaccessible to the user but also
to provide an additional way to debug complex error states using the
region snapshots.

Implemented commands:
$ devlink region help
$ devlink region show [ DEV/REGION ]
$ devlink region del DEV/REGION snapshot SNAPSHOT_ID
$ devlink region dump DEV/REGION [ snapshot SNAPSHOT_ID ]
$ devlink region read DEV/REGION [ snapshot SNAPSHOT_ID ]
	address ADDRESS length length

Show all of the exposed regions with region sizes:
$ devlink region show
pci/0000:00:05.0/cr-space: size 1048576 snapshot [1 2]
pci/0000:00:05.0/fw-health: size 64 snapshot [1 2]

Delete a snapshot using:
$ devlink region del pci/0000:00:05.0/cr-space snapshot 1

Dump a snapshot:
$ devlink region dump pci/0000:00:05.0/fw-health snapshot 1
0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30
0000000000000010 0000 0000 ffff ff04 0029 8c00 0028 8cc8
0000000000000020 0016 0bb8 0016 1720 0000 0000 c00f 3ffc
0000000000000030 bada cce5 bada cce5 bada cce5 bada cce5

Read a specific part of a snapshot:
$ devlink region read pci/0000:00:05.0/fw-health snapshot 1 address 0
	length 16
0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30

For more information you can check devlink-region.8 man page

Future:
There is a plan to extend the support to include a write command
as well as performing read and dump live region

v1->v2:
-Add a parameter to enable devlink region snapshot
-Allocate snapshot memory using kvmalloc
-Introduce destructor function devlink_snapshot_data_dest_t to avoid
 double allocation

v2->v3:
-Fix incorrect comment in devlink.h for DEVLINK_ATTR_REGION_SIZE
 from u32 to u64
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/Makefile

@@ -3,7 +3,7 @@ obj-$(CONFIG_MLX4_CORE)		+= mlx4_core.o
 
 mlx4_core-y :=	alloc.o catas.o cmd.o cq.o eq.o fw.o fw_qos.o icm.o intf.o \
 		main.o mcg.o mr.o pd.o port.o profile.o qp.o reset.o sense.o \
-		srq.o resource_tracker.o
+		srq.o resource_tracker.o crdump.o
 
 obj-$(CONFIG_MLX4_EN)               += mlx4_en.o
 

drivers/net/ethernet/mellanox/mlx4/catas.c

@@ -178,10 +178,12 @@ void mlx4_enter_error_state(struct mlx4_dev_persistent *persist)
 
 	dev = persist->dev;
 	mlx4_err(dev, "device is going to be reset\n");
-	if (mlx4_is_slave(dev))
+	if (mlx4_is_slave(dev)) {
 		err = mlx4_reset_slave(dev);
-	else
+	} else {
+		mlx4_crdump_collect(dev);
 		err = mlx4_reset_master(dev);
+	}
 
 	if (!err) {
 		mlx4_err(dev, "device was reset successfully\n");

drivers/net/ethernet/mellanox/mlx4/crdump.c

+/*
+ * Copyright (c) 2018, Mellanox Technologies. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "mlx4.h"
+
+#define BAD_ACCESS			0xBADACCE5
+#define HEALTH_BUFFER_SIZE		0x40
+#define CR_ENABLE_BIT			swab32(BIT(6))
+#define CR_ENABLE_BIT_OFFSET		0xF3F04
+#define MAX_NUM_OF_DUMPS_TO_STORE	(8)
+
+static const char *region_cr_space_str = "cr-space";
+static const char *region_fw_health_str = "fw-health";
+
+/* Set to true in case cr enable bit was set to true before crdump */
+static bool crdump_enbale_bit_set;
+
+static void crdump_enable_crspace_access(struct mlx4_dev *dev,
+					 u8 __iomem *cr_space)
+{
+	/* Get current enable bit value */
+	crdump_enbale_bit_set =
+		readl(cr_space + CR_ENABLE_BIT_OFFSET) & CR_ENABLE_BIT;
+
+	/* Enable FW CR filter (set bit6 to 0) */
+	if (crdump_enbale_bit_set)
+		writel(readl(cr_space + CR_ENABLE_BIT_OFFSET) & ~CR_ENABLE_BIT,
+		       cr_space + CR_ENABLE_BIT_OFFSET);
+
+	/* Enable block volatile crspace accesses */
+	writel(swab32(1), cr_space + dev->caps.health_buffer_addrs +
+	       HEALTH_BUFFER_SIZE);
+}
+
+static void crdump_disable_crspace_access(struct mlx4_dev *dev,
+					  u8 __iomem *cr_space)
+{
+	/* Disable block volatile crspace accesses */
+	writel(0, cr_space + dev->caps.health_buffer_addrs +
+	       HEALTH_BUFFER_SIZE);
+
+	/* Restore FW CR filter value (set bit6 to original value) */
+	if (crdump_enbale_bit_set)
+		writel(readl(cr_space + CR_ENABLE_BIT_OFFSET) | CR_ENABLE_BIT,
+		       cr_space + CR_ENABLE_BIT_OFFSET);
+}
+
+static void mlx4_crdump_collect_crspace(struct mlx4_dev *dev,
+					u8 __iomem *cr_space,
+					u32 id)
+{
+	struct mlx4_fw_crdump *crdump = &dev->persist->crdump;
+	struct pci_dev *pdev = dev->persist->pdev;
+	unsigned long cr_res_size;
+	u8 *crspace_data;
+	int offset;
+	int err;
+
+	if (!crdump->region_crspace) {
+		mlx4_err(dev, "crdump: cr-space region is NULL\n");
+		return;
+	}
+
+	/* Try to collect CR space */
+	cr_res_size = pci_resource_len(pdev, 0);
+	crspace_data = kvmalloc(cr_res_size, GFP_KERNEL);
+	if (crspace_data) {
+		for (offset = 0; offset < cr_res_size; offset += 4)
+			*(u32 *)(crspace_data + offset) =
+					readl(cr_space + offset);
+
+		err = devlink_region_snapshot_create(crdump->region_crspace,
+						     cr_res_size, crspace_data,
+						     id, &kvfree);
+		if (err) {
+			kvfree(crspace_data);
+			mlx4_warn(dev, "crdump: devlink create %s snapshot id %d err %d\n",
+				  region_cr_space_str, id, err);
+		} else {
+			mlx4_info(dev, "crdump: added snapshot %d to devlink region %s\n",
+				  id, region_cr_space_str);
+		}
+	} else {
+		mlx4_err(dev, "crdump: Failed to allocate crspace buffer\n");
+	}
+}
+
+static void mlx4_crdump_collect_fw_health(struct mlx4_dev *dev,
+					  u8 __iomem *cr_space,
+					  u32 id)
+{
+	struct mlx4_fw_crdump *crdump = &dev->persist->crdump;
+	u8 *health_data;
+	int offset;
+	int err;
+
+	if (!crdump->region_fw_health) {
+		mlx4_err(dev, "crdump: fw-health region is NULL\n");
+		return;
+	}
+
+	/* Try to collect health buffer */
+	health_data = kvmalloc(HEALTH_BUFFER_SIZE, GFP_KERNEL);
+	if (health_data) {
+		u8 __iomem *health_buf_start =
+				cr_space + dev->caps.health_buffer_addrs;
+
+		for (offset = 0; offset < HEALTH_BUFFER_SIZE; offset += 4)
+			*(u32 *)(health_data + offset) =
+					readl(health_buf_start + offset);
+
+		err = devlink_region_snapshot_create(crdump->region_fw_health,
+						     HEALTH_BUFFER_SIZE,
+						     health_data,
+						     id, &kvfree);
+		if (err) {
+			kvfree(health_data);
+			mlx4_warn(dev, "crdump: devlink create %s snapshot id %d err %d\n",
+				  region_fw_health_str, id, err);
+		} else {
+			mlx4_info(dev, "crdump: added snapshot %d to devlink region %s\n",
+				  id, region_fw_health_str);
+		}
+	} else {
+		mlx4_err(dev, "crdump: Failed to allocate health buffer\n");
+	}
+}
+
+int mlx4_crdump_collect(struct mlx4_dev *dev)
+{
+	struct devlink *devlink = priv_to_devlink(mlx4_priv(dev));
+	struct mlx4_fw_crdump *crdump = &dev->persist->crdump;
+	struct pci_dev *pdev = dev->persist->pdev;
+	unsigned long cr_res_size;
+	u8 __iomem *cr_space;
+	u32 id;
+
+	if (!dev->caps.health_buffer_addrs) {
+		mlx4_info(dev, "crdump: FW doesn't support health buffer access, skipping\n");
+		return 0;
+	}
+
+	if (!crdump->snapshot_enable) {
+		mlx4_info(dev, "crdump: devlink snapshot disabled, skipping\n");
+		return 0;
+	}
+
+	cr_res_size = pci_resource_len(pdev, 0);
+
+	cr_space = ioremap(pci_resource_start(pdev, 0), cr_res_size);
+	if (!cr_space) {
+		mlx4_err(dev, "crdump: Failed to map pci cr region\n");
+		return -ENODEV;
+	}
+
+	crdump_enable_crspace_access(dev, cr_space);
+
+	/* Get the available snapshot ID for the dumps */
+	id = devlink_region_shapshot_id_get(devlink);
+
+	/* Try to capture dumps */
+	mlx4_crdump_collect_crspace(dev, cr_space, id);
+	mlx4_crdump_collect_fw_health(dev, cr_space, id);
+
+	crdump_disable_crspace_access(dev, cr_space);
+
+	iounmap(cr_space);
+	return 0;
+}
+
+int mlx4_crdump_init(struct mlx4_dev *dev)
+{
+	struct devlink *devlink = priv_to_devlink(mlx4_priv(dev));
+	struct mlx4_fw_crdump *crdump = &dev->persist->crdump;
+	struct pci_dev *pdev = dev->persist->pdev;
+
+	crdump->snapshot_enable = false;
+
+	/* Create cr-space region */
+	crdump->region_crspace =
+		devlink_region_create(devlink,
+				      region_cr_space_str,
+				      MAX_NUM_OF_DUMPS_TO_STORE,
+				      pci_resource_len(pdev, 0));
+	if (IS_ERR(crdump->region_crspace))
+		mlx4_warn(dev, "crdump: create devlink region %s err %ld\n",
+			  region_cr_space_str,
+			  PTR_ERR(crdump->region_crspace));
+
+	/* Create fw-health region */
+	crdump->region_fw_health =
+		devlink_region_create(devlink,
+				      region_fw_health_str,
+				      MAX_NUM_OF_DUMPS_TO_STORE,
+				      HEALTH_BUFFER_SIZE);
+	if (IS_ERR(crdump->region_fw_health))
+		mlx4_warn(dev, "crdump: create devlink region %s err %ld\n",
+			  region_fw_health_str,
+			  PTR_ERR(crdump->region_fw_health));
+
+	return 0;
+}
+
+void mlx4_crdump_end(struct mlx4_dev *dev)
+{
+	struct mlx4_fw_crdump *crdump = &dev->persist->crdump;
+
+	devlink_region_destroy(crdump->region_fw_health);
+	devlink_region_destroy(crdump->region_crspace);
+}

drivers/net/ethernet/mellanox/mlx4/fw.c

@@ -825,7 +825,7 @@ int mlx4_QUERY_DEV_CAP(struct mlx4_dev *dev, struct mlx4_dev_cap *dev_cap)
 #define QUERY_DEV_CAP_QP_RATE_LIMIT_NUM_OFFSET	0xcc
 #define QUERY_DEV_CAP_QP_RATE_LIMIT_MAX_OFFSET	0xd0
 #define QUERY_DEV_CAP_QP_RATE_LIMIT_MIN_OFFSET	0xd2
-
+#define QUERY_DEV_CAP_HEALTH_BUFFER_ADDRESS_OFFSET	0xe4
 
 	dev_cap->flags2 = 0;
 	mailbox = mlx4_alloc_cmd_mailbox(dev);
@@ -1082,6 +1082,9 @@ int mlx4_QUERY_DEV_CAP(struct mlx4_dev *dev, struct mlx4_dev_cap *dev_cap)
 		dev_cap->rl_caps.min_unit = size >> 14;
 	}
 
+	MLX4_GET(dev_cap->health_buffer_addrs, outbox,
+		 QUERY_DEV_CAP_HEALTH_BUFFER_ADDRESS_OFFSET);
+
 	MLX4_GET(field32, outbox, QUERY_DEV_CAP_EXT_2_FLAGS_OFFSET);
 	if (field32 & (1 << 16))
 		dev_cap->flags2 |= MLX4_DEV_CAP_FLAG2_UPDATE_QP;

drivers/net/ethernet/mellanox/mlx4/fw.h

@@ -128,6 +128,7 @@ struct mlx4_dev_cap {
 	u32 dmfs_high_rate_qpn_base;
 	u32 dmfs_high_rate_qpn_range;
 	struct mlx4_rate_limit_caps rl_caps;
+	u32 health_buffer_addrs;
 	struct mlx4_port_cap port_cap[MLX4_MAX_PORTS + 1];
 	bool wol_port[MLX4_MAX_PORTS + 1];
 };

drivers/net/ethernet/mellanox/mlx4/main.c

@@ -191,6 +191,26 @@ static int mlx4_devlink_ierr_reset_set(struct devlink *devlink, u32 id,
 	return 0;
 }
 
+static int mlx4_devlink_crdump_snapshot_get(struct devlink *devlink, u32 id,
+					    struct devlink_param_gset_ctx *ctx)
+{
+	struct mlx4_priv *priv = devlink_priv(devlink);
+	struct mlx4_dev *dev = &priv->dev;
+
+	ctx->val.vbool = dev->persist->crdump.snapshot_enable;
+	return 0;
+}
+
+static int mlx4_devlink_crdump_snapshot_set(struct devlink *devlink, u32 id,
+					    struct devlink_param_gset_ctx *ctx)
+{
+	struct mlx4_priv *priv = devlink_priv(devlink);
+	struct mlx4_dev *dev = &priv->dev;
+
+	dev->persist->crdump.snapshot_enable = ctx->val.vbool;
+	return 0;
+}
+
 static int
 mlx4_devlink_max_macs_validate(struct devlink *devlink, u32 id,
 			       union devlink_param_value val,
@@ -224,6 +244,11 @@ static const struct devlink_param mlx4_devlink_params[] = {
 	DEVLINK_PARAM_GENERIC(MAX_MACS,
 			      BIT(DEVLINK_PARAM_CMODE_DRIVERINIT),
 			      NULL, NULL, mlx4_devlink_max_macs_validate),
+	DEVLINK_PARAM_GENERIC(REGION_SNAPSHOT,
+			      BIT(DEVLINK_PARAM_CMODE_RUNTIME) |
+			      BIT(DEVLINK_PARAM_CMODE_DRIVERINIT),
+			      mlx4_devlink_crdump_snapshot_get,
+			      mlx4_devlink_crdump_snapshot_set, NULL),
 	DEVLINK_PARAM_DRIVER(MLX4_DEVLINK_PARAM_ID_ENABLE_64B_CQE_EQE,
 			     "enable_64b_cqe_eqe", DEVLINK_PARAM_TYPE_BOOL,
 			     BIT(DEVLINK_PARAM_CMODE_DRIVERINIT),
@@ -270,6 +295,11 @@ static void mlx4_devlink_set_params_init_values(struct devlink *devlink)
 	mlx4_devlink_set_init_value(devlink,
 				    MLX4_DEVLINK_PARAM_ID_ENABLE_4K_UAR,
 				    value);
+
+	value.vbool = false;
+	mlx4_devlink_set_init_value(devlink,
+				    DEVLINK_PARAM_GENERIC_ID_REGION_SNAPSHOT,
+				    value);
 }
 
 static inline void mlx4_set_num_reserved_uars(struct mlx4_dev *dev,
@@ -523,6 +553,7 @@ static int mlx4_dev_cap(struct mlx4_dev *dev, struct mlx4_dev_cap *dev_cap)
 	dev->caps.max_rss_tbl_sz     = dev_cap->max_rss_tbl_sz;
 	dev->caps.wol_port[1]          = dev_cap->wol_port[1];
 	dev->caps.wol_port[2]          = dev_cap->wol_port[2];
+	dev->caps.health_buffer_addrs  = dev_cap->health_buffer_addrs;
 
 	/* Save uar page shift */
 	if (!mlx4_is_slave(dev)) {
@@ -3806,10 +3837,14 @@ static int __mlx4_init_one(struct pci_dev *pdev, int pci_dev_data,
 		}
 	}
 
-	err = mlx4_catas_init(&priv->dev);
+	err = mlx4_crdump_init(&priv->dev);
 	if (err)
 		goto err_release_regions;
 
+	err = mlx4_catas_init(&priv->dev);
+	if (err)
+		goto err_crdump;
+
 	err = mlx4_load_one(pdev, pci_dev_data, total_vfs, nvfs, priv, 0);
 	if (err)
 		goto err_catas;
@@ -3819,6 +3854,9 @@ static int __mlx4_init_one(struct pci_dev *pdev, int pci_dev_data,
 err_catas:
 	mlx4_catas_end(&priv->dev);
 
+err_crdump:
+	mlx4_crdump_end(&priv->dev);
+
 err_release_regions:
 	pci_release_regions(pdev);
 
@@ -3854,6 +3892,9 @@ static int mlx4_devlink_port_type_set(struct devlink_port *devlink_port,
 
 static void mlx4_devlink_param_load_driverinit_values(struct devlink *devlink)
 {
+	struct mlx4_priv *priv = devlink_priv(devlink);
+	struct mlx4_dev *dev = &priv->dev;
+	struct mlx4_fw_crdump *crdump = &dev->persist->crdump;
 	union devlink_param_value saved_value;
 	int err;
 
@@ -3881,6 +3922,14 @@ static void mlx4_devlink_param_load_driverinit_values(struct devlink *devlink)
 						 &saved_value);
 	if (!err)
 		enable_4k_uar = saved_value.vbool;
+	err = devlink_param_driverinit_value_get(devlink,
+						 DEVLINK_PARAM_GENERIC_ID_REGION_SNAPSHOT,
+						 &saved_value);
+	if (!err && crdump->snapshot_enable != saved_value.vbool) {
+		crdump->snapshot_enable = saved_value.vbool;
+		devlink_param_value_changed(devlink,
+					    DEVLINK_PARAM_GENERIC_ID_REGION_SNAPSHOT);
+	}
 }
 
 static int mlx4_devlink_reload(struct devlink *devlink,
@@ -4080,6 +4129,7 @@ static void mlx4_remove_one(struct pci_dev *pdev)
 	else
 		mlx4_info(dev, "%s: interface is down\n", __func__);
 	mlx4_catas_end(dev);
+	mlx4_crdump_end(dev);
 	if (dev->flags & MLX4_FLAG_SRIOV && !active_vfs) {
 		mlx4_warn(dev, "Disabling SR-IOV\n");
 		pci_disable_sriov(pdev);

drivers/net/ethernet/mellanox/mlx4/mlx4.h

@@ -1042,6 +1042,8 @@ void mlx4_start_catas_poll(struct mlx4_dev *dev);
 void mlx4_stop_catas_poll(struct mlx4_dev *dev);
 int mlx4_catas_init(struct mlx4_dev *dev);
 void mlx4_catas_end(struct mlx4_dev *dev);
+int mlx4_crdump_init(struct mlx4_dev *dev);
+void mlx4_crdump_end(struct mlx4_dev *dev);
 int mlx4_restart_one(struct pci_dev *pdev, bool reload,
 		     struct devlink *devlink);
 int mlx4_register_device(struct mlx4_dev *dev);
@@ -1228,6 +1230,8 @@ void mlx4_srq_event(struct mlx4_dev *dev, u32 srqn, int event_type);
 void mlx4_enter_error_state(struct mlx4_dev_persistent *persist);
 int mlx4_comm_internal_err(u32 slave_read);
 
+int mlx4_crdump_collect(struct mlx4_dev *dev);
+
 int mlx4_SENSE_PORT(struct mlx4_dev *dev, int port,
 		    enum mlx4_port_type *type);
 void mlx4_do_sense_ports(struct mlx4_dev *dev,

include/linux/mlx4/device.h

@@ -630,6 +630,7 @@ struct mlx4_caps {
 	u32			vf_caps;
 	bool			wol_port[MLX4_MAX_PORTS + 1];
 	struct mlx4_rate_limit_caps rl_caps;
+	u32			health_buffer_addrs;
 };
 
 struct mlx4_buf_list {
@@ -851,6 +852,12 @@ struct mlx4_vf_dev {
 	u8			n_ports;
 };
 
+struct mlx4_fw_crdump {
+	bool snapshot_enable;
+	struct devlink_region *region_crspace;
+	struct devlink_region *region_fw_health;
+};
+
 enum mlx4_pci_status {
 	MLX4_PCI_STATUS_DISABLED,
 	MLX4_PCI_STATUS_ENABLED,
@@ -871,6 +878,7 @@ struct mlx4_dev_persistent {
 	u8	interface_state;
 	struct mutex		pci_status_mutex; /* sync pci state */
 	enum mlx4_pci_status	pci_status;
+	struct mlx4_fw_crdump	crdump;
 };
 
 struct mlx4_dev {

include/net/devlink.h

@@ -28,6 +28,8 @@ struct devlink {
 	struct list_head dpipe_table_list;
 	struct list_head resource_list;
 	struct list_head param_list;
+	struct list_head region_list;
+	u32 snapshot_id;
 	struct devlink_dpipe_headers *dpipe_headers;
 	const struct devlink_ops *ops;
 	struct device *dev;
@@ -359,6 +361,7 @@ enum devlink_param_generic_id {
 	DEVLINK_PARAM_GENERIC_ID_INT_ERR_RESET,
 	DEVLINK_PARAM_GENERIC_ID_MAX_MACS,
 	DEVLINK_PARAM_GENERIC_ID_ENABLE_SRIOV,
+	DEVLINK_PARAM_GENERIC_ID_REGION_SNAPSHOT,
 
 	/* add new param generic ids above here*/
 	__DEVLINK_PARAM_GENERIC_ID_MAX,
@@ -374,6 +377,9 @@ enum devlink_param_generic_id {
 #define DEVLINK_PARAM_GENERIC_ENABLE_SRIOV_NAME "enable_sriov"
 #define DEVLINK_PARAM_GENERIC_ENABLE_SRIOV_TYPE DEVLINK_PARAM_TYPE_BOOL
 
+#define DEVLINK_PARAM_GENERIC_REGION_SNAPSHOT_NAME "region_snapshot_enable"
+#define DEVLINK_PARAM_GENERIC_REGION_SNAPSHOT_TYPE DEVLINK_PARAM_TYPE_BOOL
+
 #define DEVLINK_PARAM_GENERIC(_id, _cmodes, _get, _set, _validate)	\
 {									\
 	.id = DEVLINK_PARAM_GENERIC_ID_##_id,				\
@@ -397,6 +403,10 @@ enum devlink_param_generic_id {
 	.validate = _validate,						\
 }
 
+struct devlink_region;
+
+typedef void devlink_snapshot_data_dest_t(const void *data);
+
 struct devlink_ops {
 	int (*reload)(struct devlink *devlink, struct netlink_ext_ack *extack);
 	int (*port_type_set)(struct devlink_port *devlink_port,
@@ -543,6 +553,15 @@ int devlink_param_driverinit_value_get(struct devlink *devlink, u32 param_id,
 int devlink_param_driverinit_value_set(struct devlink *devlink, u32 param_id,
 				       union devlink_param_value init_val);
 void devlink_param_value_changed(struct devlink *devlink, u32 param_id);
+struct devlink_region *devlink_region_create(struct devlink *devlink,
+					     const char *region_name,
+					     u32 region_max_snapshots,
+					     u64 region_size);
+void devlink_region_destroy(struct devlink_region *region);
+u32 devlink_region_shapshot_id_get(struct devlink *devlink);
+int devlink_region_snapshot_create(struct devlink_region *region, u64 data_len,
+				   u8 *data, u32 snapshot_id,
+				   devlink_snapshot_data_dest_t *data_destructor);
 
 #else
 
@@ -770,6 +789,34 @@ devlink_param_value_changed(struct devlink *devlink, u32 param_id)
 {
 }
 
+static inline struct devlink_region *
+devlink_region_create(struct devlink *devlink,
+		      const char *region_name,
+		      u32 region_max_snapshots,
+		      u64 region_size)
+{
+	return NULL;
+}
+
+static inline void
+devlink_region_destroy(struct devlink_region *region)
+{
+}
+
+static inline u32
+devlink_region_shapshot_id_get(struct devlink *devlink)
+{
+	return 0;
+}
+
+static inline int
+devlink_region_snapshot_create(struct devlink_region *region, u64 data_len,
+			       u8 *data, u32 snapshot_id,
+			       devlink_snapshot_data_dest_t *data_destructor)
+{
+	return 0;
+}
+
 #endif
 
 #endif /* _NET_DEVLINK_H_ */

include/uapi/linux/devlink.h

@@ -83,6 +83,12 @@ enum devlink_command {
 	DEVLINK_CMD_PARAM_NEW,
 	DEVLINK_CMD_PARAM_DEL,
 
+	DEVLINK_CMD_REGION_GET,
+	DEVLINK_CMD_REGION_SET,
+	DEVLINK_CMD_REGION_NEW,
+	DEVLINK_CMD_REGION_DEL,
+	DEVLINK_CMD_REGION_READ,
+
 	/* add new commands above here */
 	__DEVLINK_CMD_MAX,
 	DEVLINK_CMD_MAX = __DEVLINK_CMD_MAX - 1
@@ -262,6 +268,18 @@ enum devlink_attr {
 	DEVLINK_ATTR_PARAM_VALUE_DATA,		/* dynamic */
 	DEVLINK_ATTR_PARAM_VALUE_CMODE,		/* u8 */
 
+	DEVLINK_ATTR_REGION_NAME,               /* string */
+	DEVLINK_ATTR_REGION_SIZE,               /* u64 */
+	DEVLINK_ATTR_REGION_SNAPSHOTS,          /* nested */
+	DEVLINK_ATTR_REGION_SNAPSHOT,           /* nested */
+	DEVLINK_ATTR_REGION_SNAPSHOT_ID,        /* u32 */
+
+	DEVLINK_ATTR_REGION_CHUNKS,             /* nested */
+	DEVLINK_ATTR_REGION_CHUNK,              /* nested */
+	DEVLINK_ATTR_REGION_CHUNK_DATA,         /* binary */
+	DEVLINK_ATTR_REGION_CHUNK_ADDR,         /* u64 */
+	DEVLINK_ATTR_REGION_CHUNK_LEN,          /* u64 */
+
 	/* add new attributes above here, update the policy in devlink.c */
 
 	__DEVLINK_ATTR_MAX,

net/core/devlink.c

@@ -326,6 +326,57 @@ devlink_sb_tc_index_get_from_info(struct devlink_sb *devlink_sb,
 						  pool_type, p_tc_index);
 }
 
+struct devlink_region {
+	struct devlink *devlink;
+	struct list_head list;
+	const char *name;
+	struct list_head snapshot_list;
+	u32 max_snapshots;
+	u32 cur_snapshots;
+	u64 size;
+};
+
+struct devlink_snapshot {
+	struct list_head list;
+	struct devlink_region *region;
+	devlink_snapshot_data_dest_t *data_destructor;
+	u64 data_len;
+	u8 *data;
+	u32 id;
+};
+
+static struct devlink_region *
+devlink_region_get_by_name(struct devlink *devlink, const char *region_name)
+{
+	struct devlink_region *region;
+
+	list_for_each_entry(region, &devlink->region_list, list)
+		if (!strcmp(region->name, region_name))
+			return region;
+
+	return NULL;
+}
+
+static struct devlink_snapshot *
+devlink_region_snapshot_get_by_id(struct devlink_region *region, u32 id)
+{
+	struct devlink_snapshot *snapshot;
+
+	list_for_each_entry(snapshot, &region->snapshot_list, list)
+		if (snapshot->id == id)
+			return snapshot;
+
+	return NULL;
+}
+
+static void devlink_region_snapshot_del(struct devlink_snapshot *snapshot)
+{
+	snapshot->region->cur_snapshots--;
+	list_del(&snapshot->list);
+	(*snapshot->data_destructor)(snapshot->data);
+	kfree(snapshot);
+}
+
 #define DEVLINK_NL_FLAG_NEED_DEVLINK	BIT(0)
 #define DEVLINK_NL_FLAG_NEED_PORT	BIT(1)
 #define DEVLINK_NL_FLAG_NEED_SB		BIT(2)
@@ -2620,6 +2671,11 @@ static const struct devlink_param devlink_param_generic[] = {
 		.name = DEVLINK_PARAM_GENERIC_ENABLE_SRIOV_NAME,
 		.type = DEVLINK_PARAM_GENERIC_ENABLE_SRIOV_TYPE,
 	},
+	{
+		.id = DEVLINK_PARAM_GENERIC_ID_REGION_SNAPSHOT,
+		.name = DEVLINK_PARAM_GENERIC_REGION_SNAPSHOT_NAME,
+		.type = DEVLINK_PARAM_GENERIC_REGION_SNAPSHOT_TYPE,
+	},
 };
 
 static int devlink_param_generic_verify(const struct devlink_param *param)
@@ -3098,6 +3154,420 @@ static void devlink_param_unregister_one(struct devlink *devlink,
 	kfree(param_item);
 }
 
+static int devlink_nl_region_snapshot_id_put(struct sk_buff *msg,
+					     struct devlink *devlink,
+					     struct devlink_snapshot *snapshot)
+{
+	struct nlattr *snap_attr;
+	int err;
+
+	snap_attr = nla_nest_start(msg, DEVLINK_ATTR_REGION_SNAPSHOT);
+	if (!snap_attr)
+		return -EINVAL;
+
+	err = nla_put_u32(msg, DEVLINK_ATTR_REGION_SNAPSHOT_ID, snapshot->id);
+	if (err)
+		goto nla_put_failure;
+
+	nla_nest_end(msg, snap_attr);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, snap_attr);
+	return err;
+}
+
+static int devlink_nl_region_snapshots_id_put(struct sk_buff *msg,
+					      struct devlink *devlink,
+					      struct devlink_region *region)
+{
+	struct devlink_snapshot *snapshot;
+	struct nlattr *snapshots_attr;
+	int err;
+
+	snapshots_attr = nla_nest_start(msg, DEVLINK_ATTR_REGION_SNAPSHOTS);
+	if (!snapshots_attr)
+		return -EINVAL;
+
+	list_for_each_entry(snapshot, &region->snapshot_list, list) {
+		err = devlink_nl_region_snapshot_id_put(msg, devlink, snapshot);
+		if (err)
+			goto nla_put_failure;
+	}
+
+	nla_nest_end(msg, snapshots_attr);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, snapshots_attr);
+	return err;
+}
+
+static int devlink_nl_region_fill(struct sk_buff *msg, struct devlink *devlink,
+				  enum devlink_command cmd, u32 portid,
+				  u32 seq, int flags,
+				  struct devlink_region *region)
+{
+	void *hdr;
+	int err;
+
+	hdr = genlmsg_put(msg, portid, seq, &devlink_nl_family, flags, cmd);
+	if (!hdr)
+		return -EMSGSIZE;
+
+	err = devlink_nl_put_handle(msg, devlink);
+	if (err)
+		goto nla_put_failure;
+
+	err = nla_put_string(msg, DEVLINK_ATTR_REGION_NAME, region->name);
+	if (err)
+		goto nla_put_failure;
+
+	err = nla_put_u64_64bit(msg, DEVLINK_ATTR_REGION_SIZE,
+				region->size,
+				DEVLINK_ATTR_PAD);
+	if (err)
+		goto nla_put_failure;
+
+	err = devlink_nl_region_snapshots_id_put(msg, devlink, region);
+	if (err)
+		goto nla_put_failure;
+
+	genlmsg_end(msg, hdr);
+	return 0;
+
+nla_put_failure:
+	genlmsg_cancel(msg, hdr);
+	return err;
+}
+
+static void devlink_nl_region_notify(struct devlink_region *region,
+				     struct devlink_snapshot *snapshot,
+				     enum devlink_command cmd)
+{
+	struct devlink *devlink = region->devlink;
+	struct sk_buff *msg;
+	void *hdr;
+	int err;
+
+	WARN_ON(cmd != DEVLINK_CMD_REGION_NEW && cmd != DEVLINK_CMD_REGION_DEL);
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return;
+
+	hdr = genlmsg_put(msg, 0, 0, &devlink_nl_family, 0, cmd);
+	if (!hdr)
+		goto out_free_msg;
+
+	err = devlink_nl_put_handle(msg, devlink);
+	if (err)
+		goto out_cancel_msg;
+
+	err = nla_put_string(msg, DEVLINK_ATTR_REGION_NAME,
+			     region->name);
+	if (err)
+		goto out_cancel_msg;
+
+	if (snapshot) {
+		err = nla_put_u32(msg, DEVLINK_ATTR_REGION_SNAPSHOT_ID,
+				  snapshot->id);
+		if (err)
+			goto out_cancel_msg;
+	} else {
+		err = nla_put_u64_64bit(msg, DEVLINK_ATTR_REGION_SIZE,
+					region->size, DEVLINK_ATTR_PAD);
+		if (err)
+			goto out_cancel_msg;
+	}
+	genlmsg_end(msg, hdr);
+
+	genlmsg_multicast_netns(&devlink_nl_family, devlink_net(devlink),
+				msg, 0, DEVLINK_MCGRP_CONFIG, GFP_KERNEL);
+
+	return;
+
+out_cancel_msg:
+	genlmsg_cancel(msg, hdr);
+out_free_msg:
+	nlmsg_free(msg);
+}
+
+static int devlink_nl_cmd_region_get_doit(struct sk_buff *skb,
+					  struct genl_info *info)
+{
+	struct devlink *devlink = info->user_ptr[0];
+	struct devlink_region *region;
+	const char *region_name;
+	struct sk_buff *msg;
+	int err;
+
+	if (!info->attrs[DEVLINK_ATTR_REGION_NAME])
+		return -EINVAL;
+
+	region_name = nla_data(info->attrs[DEVLINK_ATTR_REGION_NAME]);
+	region = devlink_region_get_by_name(devlink, region_name);
+	if (!region)
+		return -EINVAL;
+
+	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	err = devlink_nl_region_fill(msg, devlink, DEVLINK_CMD_REGION_GET,
+				     info->snd_portid, info->snd_seq, 0,
+				     region);
+	if (err) {
+		nlmsg_free(msg);
+		return err;
+	}
+
+	return genlmsg_reply(msg, info);
+}
+
+static int devlink_nl_cmd_region_get_dumpit(struct sk_buff *msg,
+					    struct netlink_callback *cb)
+{
+	struct devlink_region *region;
+	struct devlink *devlink;
+	int start = cb->args[0];
+	int idx = 0;
+	int err;
+
+	mutex_lock(&devlink_mutex);
+	list_for_each_entry(devlink, &devlink_list, list) {
+		if (!net_eq(devlink_net(devlink), sock_net(msg->sk)))
+			continue;
+
+		mutex_lock(&devlink->lock);
+		list_for_each_entry(region, &devlink->region_list, list) {
+			if (idx < start) {
+				idx++;
+				continue;
+			}
+			err = devlink_nl_region_fill(msg, devlink,
+						     DEVLINK_CMD_REGION_GET,
+						     NETLINK_CB(cb->skb).portid,
+						     cb->nlh->nlmsg_seq,
+						     NLM_F_MULTI, region);
+			if (err) {
+				mutex_unlock(&devlink->lock);
+				goto out;
+			}
+			idx++;
+		}
+		mutex_unlock(&devlink->lock);
+	}
+out:
+	mutex_unlock(&devlink_mutex);
+	cb->args[0] = idx;
+	return msg->len;
+}
+
+static int devlink_nl_cmd_region_del(struct sk_buff *skb,
+				     struct genl_info *info)
+{
+	struct devlink *devlink = info->user_ptr[0];
+	struct devlink_snapshot *snapshot;
+	struct devlink_region *region;
+	const char *region_name;
+	u32 snapshot_id;
+
+	if (!info->attrs[DEVLINK_ATTR_REGION_NAME] ||
+	    !info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID])
+		return -EINVAL;
+
+	region_name = nla_data(info->attrs[DEVLINK_ATTR_REGION_NAME]);
+	snapshot_id = nla_get_u32(info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]);
+
+	region = devlink_region_get_by_name(devlink, region_name);
+	if (!region)
+		return -EINVAL;
+
+	snapshot = devlink_region_snapshot_get_by_id(region, snapshot_id);
+	if (!snapshot)
+		return -EINVAL;
+
+	devlink_nl_region_notify(region, snapshot, DEVLINK_CMD_REGION_DEL);
+	devlink_region_snapshot_del(snapshot);
+	return 0;
+}
+
+static int devlink_nl_cmd_region_read_chunk_fill(struct sk_buff *msg,
+						 struct devlink *devlink,
+						 u8 *chunk, u32 chunk_size,
+						 u64 addr)
+{
+	struct nlattr *chunk_attr;
+	int err;
+
+	chunk_attr = nla_nest_start(msg, DEVLINK_ATTR_REGION_CHUNK);
+	if (!chunk_attr)
+		return -EINVAL;
+
+	err = nla_put(msg, DEVLINK_ATTR_REGION_CHUNK_DATA, chunk_size, chunk);
+	if (err)
+		goto nla_put_failure;
+
+	err = nla_put_u64_64bit(msg, DEVLINK_ATTR_REGION_CHUNK_ADDR, addr,
+				DEVLINK_ATTR_PAD);
+	if (err)
+		goto nla_put_failure;
+
+	nla_nest_end(msg, chunk_attr);
+	return 0;
+
+nla_put_failure:
+	nla_nest_cancel(msg, chunk_attr);
+	return err;
+}
+
+#define DEVLINK_REGION_READ_CHUNK_SIZE 256
+
+static int devlink_nl_region_read_snapshot_fill(struct sk_buff *skb,
+						struct devlink *devlink,
+						struct devlink_region *region,
+						struct nlattr **attrs,
+						u64 start_offset,
+						u64 end_offset,
+						bool dump,
+						u64 *new_offset)
+{
+	struct devlink_snapshot *snapshot;
+	u64 curr_offset = start_offset;
+	u32 snapshot_id;
+	int err = 0;
+
+	*new_offset = start_offset;
+
+	snapshot_id = nla_get_u32(attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]);
+	snapshot = devlink_region_snapshot_get_by_id(region, snapshot_id);
+	if (!snapshot)
+		return -EINVAL;
+
+	if (end_offset > snapshot->data_len || dump)
+		end_offset = snapshot->data_len;
+
+	while (curr_offset < end_offset) {
+		u32 data_size;
+		u8 *data;
+
+		if (end_offset - curr_offset < DEVLINK_REGION_READ_CHUNK_SIZE)
+			data_size = end_offset - curr_offset;
+		else
+			data_size = DEVLINK_REGION_READ_CHUNK_SIZE;
+
+		data = &snapshot->data[curr_offset];
+		err = devlink_nl_cmd_region_read_chunk_fill(skb, devlink,
+							    data, data_size,
+							    curr_offset);
+		if (err)
+			break;
+
+		curr_offset += data_size;
+	}
+	*new_offset = curr_offset;
+
+	return err;
+}
+
+static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
+					     struct netlink_callback *cb)
+{
+	u64 ret_offset, start_offset, end_offset = 0;
+	struct nlattr *attrs[DEVLINK_ATTR_MAX + 1];
+	const struct genl_ops *ops = cb->data;
+	struct devlink_region *region;
+	struct nlattr *chunks_attr;
+	const char *region_name;
+	struct devlink *devlink;
+	bool dump = true;
+	void *hdr;
+	int err;
+
+	start_offset = *((u64 *)&cb->args[0]);
+
+	err = nlmsg_parse(cb->nlh, GENL_HDRLEN + devlink_nl_family.hdrsize,
+			  attrs, DEVLINK_ATTR_MAX, ops->policy, NULL);
+	if (err)
+		goto out;
+
+	devlink = devlink_get_from_attrs(sock_net(cb->skb->sk), attrs);
+	if (IS_ERR(devlink))
+		goto out;
+
+	mutex_lock(&devlink_mutex);
+	mutex_lock(&devlink->lock);
+
+	if (!attrs[DEVLINK_ATTR_REGION_NAME] ||
+	    !attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID])
+		goto out_unlock;
+
+	region_name = nla_data(attrs[DEVLINK_ATTR_REGION_NAME]);
+	region = devlink_region_get_by_name(devlink, region_name);
+	if (!region)
+		goto out_unlock;
+
+	hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+			  &devlink_nl_family, NLM_F_ACK | NLM_F_MULTI,
+			  DEVLINK_CMD_REGION_READ);
+	if (!hdr)
+		goto out_unlock;
+
+	err = devlink_nl_put_handle(skb, devlink);
+	if (err)
+		goto nla_put_failure;
+
+	err = nla_put_string(skb, DEVLINK_ATTR_REGION_NAME, region_name);
+	if (err)
+		goto nla_put_failure;
+
+	chunks_attr = nla_nest_start(skb, DEVLINK_ATTR_REGION_CHUNKS);
+	if (!chunks_attr)
+		goto nla_put_failure;
+
+	if (attrs[DEVLINK_ATTR_REGION_CHUNK_ADDR] &&
+	    attrs[DEVLINK_ATTR_REGION_CHUNK_LEN]) {
+		if (!start_offset)
+			start_offset =
+				nla_get_u64(attrs[DEVLINK_ATTR_REGION_CHUNK_ADDR]);
+
+		end_offset = nla_get_u64(attrs[DEVLINK_ATTR_REGION_CHUNK_ADDR]);
+		end_offset += nla_get_u64(attrs[DEVLINK_ATTR_REGION_CHUNK_LEN]);
+		dump = false;
+	}
+
+	err = devlink_nl_region_read_snapshot_fill(skb, devlink,
+						   region, attrs,
+						   start_offset,
+						   end_offset, dump,
+						   &ret_offset);
+
+	if (err && err != -EMSGSIZE)
+		goto nla_put_failure;
+
+	/* Check if there was any progress done to prevent infinite loop */
+	if (ret_offset == start_offset)
+		goto nla_put_failure;
+
+	*((u64 *)&cb->args[0]) = ret_offset;
+
+	nla_nest_end(skb, chunks_attr);
+	genlmsg_end(skb, hdr);
+	mutex_unlock(&devlink->lock);
+	mutex_unlock(&devlink_mutex);
+
+	return skb->len;
+
+nla_put_failure:
+	genlmsg_cancel(skb, hdr);
+out_unlock:
+	mutex_unlock(&devlink->lock);
+	mutex_unlock(&devlink_mutex);
+out:
+	return 0;
+}
+
 static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
 	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING },
 	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING },
@@ -3121,6 +3591,8 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
 	[DEVLINK_ATTR_PARAM_NAME] = { .type = NLA_NUL_STRING },
 	[DEVLINK_ATTR_PARAM_TYPE] = { .type = NLA_U8 },
 	[DEVLINK_ATTR_PARAM_VALUE_CMODE] = { .type = NLA_U8 },
+	[DEVLINK_ATTR_REGION_NAME] = { .type = NLA_NUL_STRING },
+	[DEVLINK_ATTR_REGION_SNAPSHOT_ID] = { .type = NLA_U32 },
 };
 
 static const struct genl_ops devlink_nl_ops[] = {
@@ -3319,6 +3791,28 @@ static const struct genl_ops devlink_nl_ops[] = {
 		.flags = GENL_ADMIN_PERM,
 		.internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,
 	},
+	{
+		.cmd = DEVLINK_CMD_REGION_GET,
+		.doit = devlink_nl_cmd_region_get_doit,
+		.dumpit = devlink_nl_cmd_region_get_dumpit,
+		.policy = devlink_nl_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,
+	},
+	{
+		.cmd = DEVLINK_CMD_REGION_DEL,
+		.doit = devlink_nl_cmd_region_del,
+		.policy = devlink_nl_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,
+	},
+	{
+		.cmd = DEVLINK_CMD_REGION_READ,
+		.dumpit = devlink_nl_cmd_region_read_dumpit,
+		.policy = devlink_nl_policy,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = DEVLINK_NL_FLAG_NEED_DEVLINK,
+	},
 };
 
 static struct genl_family devlink_nl_family __ro_after_init = {
@@ -3358,6 +3852,7 @@ struct devlink *devlink_alloc(const struct devlink_ops *ops, size_t priv_size)
 	INIT_LIST_HEAD_RCU(&devlink->dpipe_table_list);
 	INIT_LIST_HEAD(&devlink->resource_list);
 	INIT_LIST_HEAD(&devlink->param_list);
+	INIT_LIST_HEAD(&devlink->region_list);
 	mutex_init(&devlink->lock);
 	return devlink;
 }
@@ -4109,6 +4604,158 @@ void devlink_param_value_changed(struct devlink *devlink, u32 param_id)
 }
 EXPORT_SYMBOL_GPL(devlink_param_value_changed);
 
+/**
+ *	devlink_region_create - create a new address region
+ *
+ *	@devlink: devlink
+ *	@region_name: region name
+ *	@region_max_snapshots: Maximum supported number of snapshots for region
+ *	@region_size: size of region
+ */
+struct devlink_region *devlink_region_create(struct devlink *devlink,
+					     const char *region_name,
+					     u32 region_max_snapshots,
+					     u64 region_size)
+{
+	struct devlink_region *region;
+	int err = 0;
+
+	mutex_lock(&devlink->lock);
+
+	if (devlink_region_get_by_name(devlink, region_name)) {
+		err = -EEXIST;
+		goto unlock;
+	}
+
+	region = kzalloc(sizeof(*region), GFP_KERNEL);
+	if (!region) {
+		err = -ENOMEM;
+		goto unlock;
+	}
+
+	region->devlink = devlink;
+	region->max_snapshots = region_max_snapshots;
+	region->name = region_name;
+	region->size = region_size;
+	INIT_LIST_HEAD(&region->snapshot_list);
+	list_add_tail(&region->list, &devlink->region_list);
+	devlink_nl_region_notify(region, NULL, DEVLINK_CMD_REGION_NEW);
+
+	mutex_unlock(&devlink->lock);
+	return region;
+
+unlock:
+	mutex_unlock(&devlink->lock);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(devlink_region_create);
+
+/**
+ *	devlink_region_destroy - destroy address region
+ *
+ *	@region: devlink region to destroy
+ */
+void devlink_region_destroy(struct devlink_region *region)
+{
+	struct devlink *devlink = region->devlink;
+	struct devlink_snapshot *snapshot, *ts;
+
+	mutex_lock(&devlink->lock);
+
+	/* Free all snapshots of region */
+	list_for_each_entry_safe(snapshot, ts, &region->snapshot_list, list)
+		devlink_region_snapshot_del(snapshot);
+
+	list_del(&region->list);
+
+	devlink_nl_region_notify(region, NULL, DEVLINK_CMD_REGION_DEL);
+	mutex_unlock(&devlink->lock);
+	kfree(region);
+}
+EXPORT_SYMBOL_GPL(devlink_region_destroy);
+
+/**
+ *	devlink_region_shapshot_id_get - get snapshot ID
+ *
+ *	This callback should be called when adding a new snapshot,
+ *	Driver should use the same id for multiple snapshots taken
+ *	on multiple regions at the same time/by the same trigger.
+ *
+ *	@devlink: devlink
+ */
+u32 devlink_region_shapshot_id_get(struct devlink *devlink)
+{
+	u32 id;
+
+	mutex_lock(&devlink->lock);
+	id = ++devlink->snapshot_id;
+	mutex_unlock(&devlink->lock);
+
+	return id;
+}
+EXPORT_SYMBOL_GPL(devlink_region_shapshot_id_get);
+
+/**
+ *	devlink_region_snapshot_create - create a new snapshot
+ *	This will add a new snapshot of a region. The snapshot
+ *	will be stored on the region struct and can be accessed
+ *	from devlink. This is useful for future	analyses of snapshots.
+ *	Multiple snapshots can be created on a region.
+ *	The @snapshot_id should be obtained using the getter function.
+ *
+ *	@devlink_region: devlink region of the snapshot
+ *	@data_len: size of snapshot data
+ *	@data: snapshot data
+ *	@snapshot_id: snapshot id to be created
+ *	@data_destructor: pointer to destructor function to free data
+ */
+int devlink_region_snapshot_create(struct devlink_region *region, u64 data_len,
+				   u8 *data, u32 snapshot_id,
+				   devlink_snapshot_data_dest_t *data_destructor)
+{
+	struct devlink *devlink = region->devlink;
+	struct devlink_snapshot *snapshot;
+	int err;
+
+	mutex_lock(&devlink->lock);
+
+	/* check if region can hold one more snapshot */
+	if (region->cur_snapshots == region->max_snapshots) {
+		err = -ENOMEM;
+		goto unlock;
+	}
+
+	if (devlink_region_snapshot_get_by_id(region, snapshot_id)) {
+		err = -EEXIST;
+		goto unlock;
+	}
+
+	snapshot = kzalloc(sizeof(*snapshot), GFP_KERNEL);
+	if (!snapshot) {
+		err = -ENOMEM;
+		goto unlock;
+	}
+
+	snapshot->id = snapshot_id;
+	snapshot->region = region;
+	snapshot->data = data;
+	snapshot->data_len = data_len;
+	snapshot->data_destructor = data_destructor;
+
+	list_add_tail(&snapshot->list, &region->snapshot_list);
+
+	region->cur_snapshots++;
+
+	devlink_nl_region_notify(region, snapshot, DEVLINK_CMD_REGION_NEW);
+	mutex_unlock(&devlink->lock);
+	return 0;
+
+unlock:
+	mutex_unlock(&devlink->lock);
+	return err;
+}
+EXPORT_SYMBOL_GPL(devlink_region_snapshot_create);
+
 static int __init devlink_module_init(void)
 {
 	return genl_register_family(&devlink_nl_family);