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From: Danielle Ratson <danieller@nvidia.com>
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Subject: [PATCH net-next v2 07/10] ethtool: cmis_cdb: Add a layer for supporting CDB commands
Date: Mon, 15 Apr 2024 15:07:14 +0300
Message-ID: <20240415120717.1251864-8-danieller@nvidia.com>
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CDB (Command Data Block Message Communication) reads and writes are
performed on memory map pages 9Fh-AFh according to the CMIS standard,
section 8.20 of revision 5.2.
Page 9Fh is used to specify the CDB command to be executed and also
provides an area for a local payload (LPL).

According to the CMIS standard, the firmware update process is done using
a CDB commands sequence that will be implemented in the next patch.

The kernel interface that will implement the firmware update using CDB
command will include 2 layers that will be added under ethtool:

* The upper layer that will be triggered from the module layer, is
  cmis_fw_update.
* The lower one is cmis_cdb.

In the future there might be more operations to implement using CDB
commands. Therefore, the idea is to keep the CDB interface clean and the
cmis_fw_update specific to the CDB commands handling it.

These two layers will communicate using the API the consists of three
functions:

- struct ethtool_cmis_cdb *
  ethtool_cmis_cdb_init(struct net_device *dev,
			struct ethtool_module_fw_flash_params *params);
- void ethtool_cmis_cdb_fini(struct ethtool_cmis_cdb *cdb);
- int ethtool_cmis_cdb_execute_cmd(struct net_device *dev,
				   struct ethtool_cmis_cdb_cmd_args *args);

Add the CDB layer to support initializing, finishing and executing CDB
commands:

* The initialization process will include creating of an ethtool_cmis_cdb
  instance, querying the module CDB support, entering and validating the
  password from user space (CMD 0x0000) and querying the module features
  (CMD 0x0040).

* The finishing API will simply free the ethtool_cmis_cdb instance.

* The executing process will write the CDB command to EEPROM using
  set_module_eeprom_by_page() that was presented earlier, and will
  process the reply from EEPROM.

Signed-off-by: Danielle Ratson <danieller@nvidia.com>
---

Notes:
    v2:
    	* Define ethtool_cmis_cdb_request::epl_len to be __be16 instead
    	  of u16.

 net/ethtool/Makefile    |   2 +-
 net/ethtool/cmis.h      | 114 ++++++++
 net/ethtool/cmis_cdb.c  | 581 ++++++++++++++++++++++++++++++++++++++++
 net/ethtool/module_fw.h |  10 +
 4 files changed, 706 insertions(+), 1 deletion(-)
 create mode 100644 net/ethtool/cmis.h
 create mode 100644 net/ethtool/cmis_cdb.c

diff --git a/net/ethtool/Makefile b/net/ethtool/Makefile
index 504f954a1b28..38806b3ecf83 100644
--- a/net/ethtool/Makefile
+++ b/net/ethtool/Makefile
@@ -8,4 +8,4 @@ ethtool_nl-y	:= netlink.o bitset.o strset.o linkinfo.o linkmodes.o rss.o \
 		   linkstate.o debug.o wol.o features.o privflags.o rings.o \
 		   channels.o coalesce.o pause.o eee.o tsinfo.o cabletest.o \
 		   tunnels.o fec.o eeprom.o stats.o phc_vclocks.o mm.o \
-		   module.o pse-pd.o plca.o mm.o
+		   module.o cmis_cdb.o pse-pd.o plca.o mm.o
diff --git a/net/ethtool/cmis.h b/net/ethtool/cmis.h
new file mode 100644
index 000000000000..2ade50eec27a
--- /dev/null
+++ b/net/ethtool/cmis.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#define ETHTOOL_CMIS_CDB_LPL_MAX_PL_LENGTH		120
+#define ETHTOOL_CMIS_CDB_CMD_PAGE			0x9F
+#define ETHTOOL_CMIS_CDB_PAGE_I2C_ADDR			0x50
+
+/**
+ * struct ethtool_cmis_cdb - CDB commands parameters
+ * @cmis_rev: CMIS revision major.
+ * @read_write_len_ext: Allowable additional number of byte octets to the LPL
+ *			in a READ or a WRITE CDB commands.
+ * @max_completion_time:  Maximum CDB command completion time in msec.
+ */
+struct ethtool_cmis_cdb {
+	u8	cmis_rev;
+	u8      read_write_len_ext;
+	u16     max_completion_time;
+};
+
+enum ethtool_cmis_cdb_cmd_id {
+	ETHTOOL_CMIS_CDB_CMD_QUERY_STATUS		= 0x0000,
+	ETHTOOL_CMIS_CDB_CMD_MODULE_FEATURES		= 0x0040,
+};
+
+/**
+ * struct ethtool_cmis_cdb_request - CDB commands request fields as decribed in
+ *				the CMIS standard
+ * @id: Command ID.
+ * @epl_len: EPL memory length.
+ * @lpl_len: LPL memory length.
+ * @chk_code: Check code for the previous field and the payload.
+ * @resv1: Added to match the CMIS standard request continuity.
+ * @resv2: Added to match the CMIS standard request continuity.
+ * @payload: Payload for the CDB commands.
+ */
+struct ethtool_cmis_cdb_request {
+	__be16 id;
+	struct_group(body,
+		__be16 epl_len;
+		u8 lpl_len;
+		u8 chk_code;
+		u8 resv1;
+		u8 resv2;
+		u8 payload[ETHTOOL_CMIS_CDB_LPL_MAX_PL_LENGTH];
+	);
+};
+
+#define CDB_F_COMPLETION_VALID		BIT(0)
+#define CDB_F_STATUS_VALID		BIT(1)
+
+/**
+ * struct ethtool_cmis_cdb_cmd_args - CDB commands execution arguments
+ * @req: CDB command fields as described in the CMIS standard.
+ * @max_duration: Maximum duration time for command completion in msec.
+ * @read_write_len_ext: Allowable additional number of byte octets to the LPL
+ *			in a READ or a WRITE commands.
+ * @rpl_exp_len: Expected reply length in bytes.
+ * @flags: Validation flags for CDB commands.
+ */
+struct ethtool_cmis_cdb_cmd_args {
+	struct ethtool_cmis_cdb_request req;
+	u16				max_duration;
+	u8				read_write_len_ext;
+	u8				msleep_pre_rpl;
+	u8                              rpl_exp_len;
+	u8				flags;
+	char				*err_msg;
+};
+
+/**
+ * struct ethtool_cmis_cdb_rpl_hdr - CDB commands reply header arguments
+ * @rpl_len: Reply length.
+ * @rpl_chk_code: Reply check code.
+ */
+struct ethtool_cmis_cdb_rpl_hdr {
+	u8 rpl_len;
+	u8 rpl_chk_code;
+};
+
+/**
+ * struct ethtool_cmis_cdb_rpl - CDB commands reply arguments
+ * @hdr: CDB commands reply header arguments.
+ * @payload: Payload for the CDB commands reply.
+ */
+struct ethtool_cmis_cdb_rpl {
+	struct ethtool_cmis_cdb_rpl_hdr hdr;
+	u8 payload[ETHTOOL_CMIS_CDB_LPL_MAX_PL_LENGTH];
+};
+
+u32 ethtool_cmis_get_max_payload_size(u8 num_of_byte_octs);
+
+void ethtool_cmis_cdb_compose_args(struct ethtool_cmis_cdb_cmd_args *args,
+				   enum ethtool_cmis_cdb_cmd_id cmd, u8 *pl,
+				   u8 lpl_len, u16 max_duration,
+				   u8 read_write_len_ext, u16 msleep_pre_rpl,
+				   u8 rpl_exp_len, u8 flags);
+
+void ethtool_cmis_cdb_check_completion_flag(u8 cmis_rev, u8 *flags);
+
+void ethtool_cmis_page_init(struct ethtool_module_eeprom *page_data,
+			    u8 page, u32 offset, u32 length);
+void ethtool_cmis_page_fini(struct ethtool_module_eeprom *page_data);
+
+struct ethtool_cmis_cdb *
+ethtool_cmis_cdb_init(struct net_device *dev,
+		      const struct ethtool_module_fw_flash_params *params);
+void ethtool_cmis_cdb_fini(struct ethtool_cmis_cdb *cdb);
+
+int ethtool_cmis_wait_for_cond(struct net_device *dev, u8 flags, u8 flag,
+			       u16 max_duration, u32 offset,
+			       bool (*cond_success)(u8), bool (*cond_fail)(u8), u8 *state);
+
+int ethtool_cmis_cdb_execute_cmd(struct net_device *dev,
+				 struct ethtool_cmis_cdb_cmd_args *args);
diff --git a/net/ethtool/cmis_cdb.c b/net/ethtool/cmis_cdb.c
new file mode 100644
index 000000000000..8cd64370910b
--- /dev/null
+++ b/net/ethtool/cmis_cdb.c
@@ -0,0 +1,581 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/ethtool.h>
+#include <linux/jiffies.h>
+
+#include "common.h"
+#include "module_fw.h"
+#include "cmis.h"
+
+/* For accessing the LPL field on page 9Fh, the allowable length extension is
+ * min(i, 15) byte octets where i specifies the allowable additional number of
+ * byte octets in a READ or a WRITE.
+ */
+u32 ethtool_cmis_get_max_payload_size(u8 num_of_byte_octs)
+{
+	return 8 * (1 + min_t(u8, num_of_byte_octs, 15));
+}
+
+void ethtool_cmis_cdb_compose_args(struct ethtool_cmis_cdb_cmd_args *args,
+				   enum ethtool_cmis_cdb_cmd_id cmd, u8 *pl,
+				   u8 lpl_len, u16 max_duration,
+				   u8 read_write_len_ext, u16 msleep_pre_rpl,
+				   u8 rpl_exp_len, u8 flags)
+{
+	args->req.id = cpu_to_be16(cmd);
+	args->req.lpl_len = lpl_len;
+	if (pl)
+		memcpy(args->req.payload, pl, args->req.lpl_len);
+
+	args->max_duration = max_duration;
+	args->read_write_len_ext =
+		ethtool_cmis_get_max_payload_size(read_write_len_ext);
+	args->msleep_pre_rpl = msleep_pre_rpl;
+	args->rpl_exp_len = rpl_exp_len;
+	args->flags = flags;
+	args->err_msg = NULL;
+}
+
+void ethtool_cmis_page_init(struct ethtool_module_eeprom *page_data,
+			    u8 page, u32 offset, u32 length)
+{
+	page_data->page = page;
+	page_data->offset = offset;
+	page_data->length = length;
+	page_data->i2c_address = ETHTOOL_CMIS_CDB_PAGE_I2C_ADDR;
+}
+
+#define CMIS_REVISION_PAGE	0x00
+#define CMIS_REVISION_OFFSET	0x01
+
+struct cmis_rev_rpl {
+	u8 rev;
+};
+
+static inline u8
+cmis_rev_rpl_major(struct cmis_rev_rpl *rpl)
+{
+	return rpl->rev >> 4;
+}
+
+static int cmis_rev_major_get(struct net_device *dev, u8 *rev_major)
+{
+	const struct ethtool_ops *ops = dev->ethtool_ops;
+	struct ethtool_module_eeprom page_data = {0};
+	struct netlink_ext_ack extack = {};
+	struct cmis_rev_rpl rpl = {};
+	int err;
+
+	ethtool_cmis_page_init(&page_data, CMIS_REVISION_PAGE,
+			       CMIS_REVISION_OFFSET, sizeof(rpl));
+	page_data.data = (u8 *)&rpl;
+
+	err = ops->get_module_eeprom_by_page(dev, &page_data, &extack);
+	if (err < 0) {
+		if (extack._msg)
+			netdev_err(dev, "%s\n", extack._msg);
+		return err;
+	}
+
+	*rev_major = cmis_rev_rpl_major(&rpl);
+
+	return 0;
+}
+
+#define CMIS_CDB_ADVERTISEMENT_PAGE	0x01
+#define CMIS_CDB_ADVERTISEMENT_OFFSET	0xA3
+
+/* Based on section 8.4.11 "CDB Messaging Support Advertisement" in CMIS
+ * standard revision 5.2.
+ */
+struct cmis_cdb_advert_rpl {
+	u8	inst_supported;
+	u8	read_write_len_ext;
+	u8	resv1;
+	u8	resv2;
+};
+
+static inline u8
+cmis_cdb_advert_rpl_inst_supported(struct cmis_cdb_advert_rpl *rpl)
+{
+	return rpl->inst_supported >> 6;
+}
+
+static int cmis_cdb_advertisement_get(struct ethtool_cmis_cdb *cdb,
+				      struct net_device *dev)
+{
+	const struct ethtool_ops *ops = dev->ethtool_ops;
+	struct ethtool_module_eeprom page_data = {};
+	struct cmis_cdb_advert_rpl rpl = {};
+	struct netlink_ext_ack extack = {};
+	int err;
+
+	ethtool_cmis_page_init(&page_data, CMIS_CDB_ADVERTISEMENT_PAGE,
+			       CMIS_CDB_ADVERTISEMENT_OFFSET, sizeof(rpl));
+	page_data.data = (u8 *)&rpl;
+
+	err = ops->get_module_eeprom_by_page(dev, &page_data, &extack);
+	if (err < 0) {
+		if (extack._msg)
+			netdev_err(dev, "%s\n", extack._msg);
+		return err;
+	}
+
+	if (!cmis_cdb_advert_rpl_inst_supported(&rpl))
+		return -EOPNOTSUPP;
+
+	cdb->read_write_len_ext = rpl.read_write_len_ext;
+
+	return 0;
+}
+
+#define CMIS_PASSWORD_ENTRY_PAGE	0x00
+#define CMIS_PASSWORD_ENTRY_OFFSET	0x7A
+
+struct cmis_password_entry_pl {
+	__be32 password;
+};
+
+/* See section 9.3.1 "CMD 0000h: Query Status" in CMIS standard revision 5.2.
+ * struct cmis_cdb_query_status_pl and struct cmis_cdb_query_status_rpl are
+ * structured layouts of the flat arrays,
+ * struct ethtool_cmis_cdb_request::payload and
+ * struct ethtool_cmis_cdb_rpl::payload respectively.
+ */
+struct cmis_cdb_query_status_pl {
+	u16 response_delay;
+};
+
+struct cmis_cdb_query_status_rpl {
+	u8 length;
+	u8 status;
+};
+
+static int
+cmis_cdb_validate_password(struct ethtool_cmis_cdb *cdb,
+			   struct net_device *dev,
+			   const struct ethtool_module_fw_flash_params *params)
+{
+	const struct ethtool_ops *ops = dev->ethtool_ops;
+	struct cmis_cdb_query_status_pl qs_pl = {0};
+	struct ethtool_module_eeprom page_data = {};
+	struct ethtool_cmis_cdb_cmd_args args = {};
+	struct cmis_password_entry_pl pe_pl = {};
+	struct cmis_cdb_query_status_rpl *rpl;
+	struct netlink_ext_ack extack = {};
+	int err;
+
+	ethtool_cmis_page_init(&page_data, CMIS_PASSWORD_ENTRY_PAGE,
+			       CMIS_PASSWORD_ENTRY_OFFSET, sizeof(pe_pl));
+	page_data.data = (u8 *)&pe_pl;
+
+	pe_pl = *((struct cmis_password_entry_pl *)page_data.data);
+	pe_pl.password = params->password;
+	err = ops->set_module_eeprom_by_page(dev, &page_data, &extack);
+	if (err < 0) {
+		if (extack._msg)
+			netdev_err(dev, "%s\n", extack._msg);
+		return err;
+	}
+
+	ethtool_cmis_cdb_compose_args(&args, ETHTOOL_CMIS_CDB_CMD_QUERY_STATUS,
+				      (u8 *)&qs_pl, sizeof(qs_pl), 0,
+				      cdb->read_write_len_ext, 1000,
+				      sizeof(*rpl),
+				      CDB_F_COMPLETION_VALID | CDB_F_STATUS_VALID);
+
+	err = ethtool_cmis_cdb_execute_cmd(dev, &args);
+	if (err < 0) {
+		ethnl_module_fw_flash_ntf_err(dev,
+					      "Query Status command failed",
+					      args.err_msg);
+		return err;
+	}
+
+	rpl = (struct cmis_cdb_query_status_rpl *)args.req.payload;
+	if (!rpl->length || !rpl->status) {
+		ethnl_module_fw_flash_ntf_err(dev, "Password was not accepted",
+					      NULL);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* Some CDB commands asserts the CDB completion flag only from CMIS
+ * revision 5. Therefore, check the relevant validity flag only when
+ * the revision supports it.
+ */
+inline void ethtool_cmis_cdb_check_completion_flag(u8 cmis_rev, u8 *flags)
+{
+	*flags |= cmis_rev >= 5 ? CDB_F_COMPLETION_VALID : 0;
+}
+
+#define CMIS_CDB_MODULE_FEATURES_RESV_DATA	34
+
+/* See section 9.4.1 "CMD 0040h: Module Features" in CMIS standard revision 5.2.
+ * struct cmis_cdb_module_features_rpl is structured layout of the flat
+ * array, ethtool_cmis_cdb_rpl::payload.
+ */
+struct cmis_cdb_module_features_rpl {
+	u8	resv1[CMIS_CDB_MODULE_FEATURES_RESV_DATA];
+	__be16	max_completion_time;
+};
+
+static inline u16
+cmis_cdb_module_features_completion_time(struct cmis_cdb_module_features_rpl *rpl)
+{
+	return be16_to_cpu(rpl->max_completion_time);
+}
+
+static int cmis_cdb_module_features_get(struct ethtool_cmis_cdb *cdb,
+					struct net_device *dev)
+{
+	struct ethtool_cmis_cdb_cmd_args args = {};
+	struct cmis_cdb_module_features_rpl *rpl;
+	u8 flags = CDB_F_STATUS_VALID;
+	int err;
+
+	ethtool_cmis_cdb_check_completion_flag(cdb->cmis_rev, &flags);
+	ethtool_cmis_cdb_compose_args(&args,
+				      ETHTOOL_CMIS_CDB_CMD_MODULE_FEATURES,
+				      NULL, 0, 0, cdb->read_write_len_ext,
+				      1000, sizeof(*rpl), flags);
+
+	err = ethtool_cmis_cdb_execute_cmd(dev, &args);
+	if (err < 0) {
+		ethnl_module_fw_flash_ntf_err(dev,
+					      "Module Features command failed",
+					      args.err_msg);
+		return err;
+	}
+
+	rpl = (struct cmis_cdb_module_features_rpl *)args.req.payload;
+	cdb->max_completion_time =
+		cmis_cdb_module_features_completion_time(rpl);
+
+	return 0;
+}
+
+struct ethtool_cmis_cdb *
+ethtool_cmis_cdb_init(struct net_device *dev,
+		      const struct ethtool_module_fw_flash_params *params)
+{
+	struct ethtool_cmis_cdb *cdb;
+	int err;
+
+	cdb = kzalloc(sizeof(*cdb), GFP_KERNEL);
+	if (!cdb)
+		return ERR_PTR(-ENOMEM);
+
+	err = cmis_rev_major_get(dev, &cdb->cmis_rev);
+	if (err < 0)
+		goto err;
+
+	if (cdb->cmis_rev < 4) {
+		ethnl_module_fw_flash_ntf_err(dev,
+					      "CMIS revision doesn't support module firmware flashing",
+					      NULL);
+		err = -EOPNOTSUPP;
+		goto err;
+	}
+
+	err = cmis_cdb_advertisement_get(cdb, dev);
+	if (err < 0)
+		goto err;
+
+	if (params->password_valid) {
+		err = cmis_cdb_validate_password(cdb, dev, params);
+		if (err < 0)
+			goto err;
+	}
+
+	err = cmis_cdb_module_features_get(cdb, dev);
+	if (err < 0)
+		goto err;
+
+	return cdb;
+
+err:
+	ethtool_cmis_cdb_fini(cdb);
+	return ERR_PTR(err);
+}
+
+void ethtool_cmis_cdb_fini(struct ethtool_cmis_cdb *cdb)
+{
+	kfree(cdb);
+}
+
+static bool is_completed(u8 data)
+{
+	return !!(data & 0x40);
+}
+
+#define CMIS_CDB_STATUS_SUCCESS	0x01
+
+static bool status_success(u8 data)
+{
+	return data == CMIS_CDB_STATUS_SUCCESS;
+}
+
+#define CMIS_CDB_STATUS_FAIL	0x40
+
+static bool status_fail(u8 data)
+{
+	return data & CMIS_CDB_STATUS_FAIL;
+}
+
+struct cmis_wait_for_cond_rpl {
+	u8 state;
+};
+
+int ethtool_cmis_wait_for_cond(struct net_device *dev, u8 flags, u8 flag,
+			       u16 max_duration, u32 offset,
+			       bool (*cond_success)(u8), bool (*cond_fail)(u8),
+			       u8 *state)
+{
+	const struct ethtool_ops *ops = dev->ethtool_ops;
+	struct ethtool_module_eeprom page_data = {0};
+	struct cmis_wait_for_cond_rpl rpl = {};
+	struct netlink_ext_ack extack = {};
+	unsigned long end;
+	int err;
+
+	if (!(flags & flag))
+		return 0;
+
+	if (max_duration == 0)
+		max_duration = U16_MAX;
+
+	end = jiffies + msecs_to_jiffies(max_duration);
+	do {
+		ethtool_cmis_page_init(&page_data, 0, offset, sizeof(rpl));
+		page_data.data = (u8 *)&rpl;
+
+		err = ops->get_module_eeprom_by_page(dev, &page_data, &extack);
+		if (err < 0) {
+			if (extack._msg)
+				netdev_err(dev, "%s\n", extack._msg);
+			continue;
+		}
+
+		if ((*cond_success)(rpl.state))
+			return 0;
+
+		if (*cond_fail && (*cond_fail)(rpl.state))
+			break;
+
+		msleep(20);
+	} while (time_before(jiffies, end));
+
+	*state = rpl.state;
+	return -EBUSY;
+}
+
+#define CMIS_CDB_COMPLETION_FLAG_OFFSET	0x08
+
+static int cmis_cdb_wait_for_completion(struct net_device *dev,
+					struct ethtool_cmis_cdb_cmd_args *args)
+{
+	u8 flag;
+	int err;
+
+	/* Some vendors demand waiting time before checking completion flag
+	 * in some CDB commands.
+	 */
+	msleep(args->msleep_pre_rpl);
+
+	err = ethtool_cmis_wait_for_cond(dev, args->flags,
+					 CDB_F_COMPLETION_VALID,
+					 args->max_duration,
+					 CMIS_CDB_COMPLETION_FLAG_OFFSET,
+					 is_completed, NULL, &flag);
+	if (err < 0)
+		args->err_msg = "Completion Flag did not set on time";
+
+	return err;
+}
+
+#define CMIS_CDB_STATUS_OFFSET	0x25
+
+static void cmis_cdb_status_fail_msg_get(u8 status, char **err_msg)
+{
+	switch (status) {
+	case 0b10000001:
+		*err_msg = "CDB Status is in progress: Busy capturing command";
+		break;
+	case 0b10000010:
+		*err_msg =
+			"CDB Status is in progress: Busy checking/validating command";
+		break;
+	case 0b10000011:
+		*err_msg = "CDB Status is in progress: Busy executing";
+		break;
+	case 0b01000000:
+		*err_msg = "CDB status failed: no specific failure";
+		break;
+	case 0b01000010:
+		*err_msg =
+			"CDB status failed: Parameter range error or parameter not supported";
+		break;
+	case 0b01000101:
+		*err_msg = "CDB status failed: CdbChkCode error";
+		break;
+	default:
+		*err_msg = "Unknown failure reason";
+	}
+};
+
+static int cmis_cdb_wait_for_status(struct net_device *dev,
+				    struct ethtool_cmis_cdb_cmd_args *args)
+{
+	u8 status;
+	int err;
+
+	/* Some vendors demand waiting time before checking status in some
+	 * CDB commands.
+	 */
+	msleep(args->msleep_pre_rpl);
+
+	err = ethtool_cmis_wait_for_cond(dev, args->flags, CDB_F_STATUS_VALID,
+					 args->max_duration,
+					 CMIS_CDB_STATUS_OFFSET,
+					 status_success, status_fail, &status);
+	if (err < 0 && !args->err_msg)
+		cmis_cdb_status_fail_msg_get(status, &args->err_msg);
+
+	return err;
+}
+
+#define CMIS_CDB_REPLY_OFFSET	0x86
+
+static int cmis_cdb_process_reply(struct net_device *dev,
+				  struct ethtool_module_eeprom *page_data,
+				  struct ethtool_cmis_cdb_cmd_args *args)
+{
+	u8 rpl_hdr_len = sizeof(struct ethtool_cmis_cdb_rpl_hdr);
+	u8 rpl_exp_len = args->rpl_exp_len + rpl_hdr_len;
+	const struct ethtool_ops *ops = dev->ethtool_ops;
+	struct netlink_ext_ack extack = {};
+	struct ethtool_cmis_cdb_rpl *rpl;
+	int err;
+
+	if (!args->rpl_exp_len)
+		return 0;
+
+	ethtool_cmis_page_init(page_data, ETHTOOL_CMIS_CDB_CMD_PAGE,
+			       CMIS_CDB_REPLY_OFFSET, rpl_exp_len);
+	page_data->data = kmalloc(page_data->length, GFP_KERNEL);
+	if (!page_data->data)
+		return -ENOMEM;
+
+	err = ops->get_module_eeprom_by_page(dev, page_data, &extack);
+	if (err < 0) {
+		if (extack._msg)
+			netdev_err(dev, "%s\n", extack._msg);
+		goto out;
+	}
+
+	rpl = (struct ethtool_cmis_cdb_rpl *)page_data->data;
+	if ((args->rpl_exp_len > rpl->hdr.rpl_len + rpl_hdr_len) ||
+	    !rpl->hdr.rpl_chk_code) {
+		err = -EIO;
+		goto out;
+	}
+
+	args->req.lpl_len = rpl->hdr.rpl_len;
+	memcpy(args->req.payload, rpl->payload, args->req.lpl_len);
+
+out:
+	kfree(page_data->data);
+	return err;
+}
+
+static int
+__ethtool_cmis_cdb_execute_cmd(struct net_device *dev,
+			       struct ethtool_module_eeprom *page_data,
+			       u8 page, u32 offset, u32 length, void *data)
+{
+	const struct ethtool_ops *ops = dev->ethtool_ops;
+	struct netlink_ext_ack extack = {};
+	int err;
+
+	ethtool_cmis_page_init(page_data, page, offset, length);
+	page_data->data = kmalloc(page_data->length, GFP_KERNEL);
+	if (!page_data->data)
+		return -ENOMEM;
+
+	memcpy(page_data->data, data, page_data->length);
+
+	err = ops->set_module_eeprom_by_page(dev, page_data, &extack);
+	if (err < 0) {
+		if (extack._msg)
+			netdev_err(dev, "%s\n", extack._msg);
+	}
+
+	kfree(page_data->data);
+	return err;
+}
+
+static u8 cmis_cdb_calc_checksum(const void *data, size_t size)
+{
+	const u8 *bytes = (const u8 *)data;
+	u8 checksum = 0;
+
+	for (size_t i = 0; i < size; i++)
+		checksum += bytes[i];
+
+	return ~checksum;
+}
+
+#define CMIS_CDB_CMD_ID_OFFSET	0x80
+
+int ethtool_cmis_cdb_execute_cmd(struct net_device *dev,
+				 struct ethtool_cmis_cdb_cmd_args *args)
+{
+	struct ethtool_module_eeprom page_data = {};
+	u32 offset;
+	int err;
+
+	args->req.chk_code =
+		cmis_cdb_calc_checksum(&args->req, sizeof(args->req));
+
+	if (args->req.lpl_len > args->read_write_len_ext) {
+		args->err_msg = "LPL length is longer than CDB read write length extension allows";
+		return -EINVAL;
+	}
+
+	/* According to the CMIS standard, there are two options to trigger the
+	 * CDB commands. The default option is triggering the command by writing
+	 * the CMDID bytes. Therefore, the command will be split to 2 calls:
+	 * First, with everything except the CMDID field and then the CMDID
+	 * field.
+	 */
+	offset = CMIS_CDB_CMD_ID_OFFSET +
+		offsetof(struct ethtool_cmis_cdb_request, body);
+	err = __ethtool_cmis_cdb_execute_cmd(dev, &page_data,
+					     ETHTOOL_CMIS_CDB_CMD_PAGE, offset,
+					     sizeof(args->req.body),
+					     &args->req.body);
+	if (err < 0)
+		return err;
+
+	offset = CMIS_CDB_CMD_ID_OFFSET +
+		offsetof(struct ethtool_cmis_cdb_request, id);
+	err = __ethtool_cmis_cdb_execute_cmd(dev, &page_data,
+					     ETHTOOL_CMIS_CDB_CMD_PAGE, offset,
+					     sizeof(args->req.id),
+					     &args->req.id);
+	if (err < 0)
+		return err;
+
+	err = cmis_cdb_wait_for_completion(dev, args);
+	if (err < 0)
+		return err;
+
+	err = cmis_cdb_wait_for_status(dev, args);
+	if (err < 0)
+		return err;
+
+	return cmis_cdb_process_reply(dev, &page_data, args);
+}
diff --git a/net/ethtool/module_fw.h b/net/ethtool/module_fw.h
index e40eae442741..96da7a8175f2 100644
--- a/net/ethtool/module_fw.h
+++ b/net/ethtool/module_fw.h
@@ -8,3 +8,13 @@ void ethnl_module_fw_flash_ntf_start(struct net_device *dev);
 void ethnl_module_fw_flash_ntf_complete(struct net_device *dev);
 void ethnl_module_fw_flash_ntf_in_progress(struct net_device *dev, u64 done,
 					   u64 total);
+
+/**
+ * struct ethtool_module_fw_flash_params - module firmware flashing parameters
+ * @password: Module password. Only valid when @pass_valid is set.
+ * @password_valid: Whether the module password is valid or not.
+ */
+struct ethtool_module_fw_flash_params {
+	__be32 password;
+	u8 password_valid:1;
+};
-- 
2.43.0