drivers/staging/greybus/bootrom.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * BOOTROM Greybus driver.
  *
  * Copyright 2016 Google Inc.
  * Copyright 2016 Linaro Ltd.
  */

 #include <linux/firmware.h>
 #include <linux/jiffies.h>
 #include <linux/mutex.h>
 #include <linux/workqueue.h>
 #include <linux/greybus.h>

 #include "firmware.h"

 /* Timeout, in jiffies, within which the next request must be received */
 #define NEXT_REQ_TIMEOUT_MS	1000

 /*
  * FIXME: Reduce this timeout once svc core handles parallel processing of
  * events from the SVC, which are handled sequentially today.
  */
 #define MODE_SWITCH_TIMEOUT_MS	10000

 enum next_request_type {
 	NEXT_REQ_FIRMWARE_SIZE,
 	NEXT_REQ_GET_FIRMWARE,
 	NEXT_REQ_READY_TO_BOOT,
 	NEXT_REQ_MODE_SWITCH,
 };

 struct gb_bootrom {
 	struct gb_connection	*connection;
 	const struct firmware	*fw;
 	u8			protocol_major;
 	u8			protocol_minor;
 	enum next_request_type	next_request;
 	struct delayed_work	dwork;
 	struct mutex		mutex; /* Protects bootrom->fw */
 };

 static void free_firmware(struct gb_bootrom *bootrom)
 {
 	if (!bootrom->fw)
 		return;

 	release_firmware(bootrom->fw);
 	bootrom->fw = NULL;
 }

 static void gb_bootrom_timedout(struct work_struct *work)
 {
 	struct delayed_work *dwork = to_delayed_work(work);
 	struct gb_bootrom *bootrom = container_of(dwork,
 						  struct gb_bootrom, dwork);
 	struct device *dev = &bootrom->connection->bundle->dev;
 	const char *reason;

 	switch (bootrom->next_request) {
 	case NEXT_REQ_FIRMWARE_SIZE:
 		reason = "Firmware Size Request";
 		break;
 	case NEXT_REQ_GET_FIRMWARE:
 		reason = "Get Firmware Request";
 		break;
 	case NEXT_REQ_READY_TO_BOOT:
 		reason = "Ready to Boot Request";
 		break;
 	case NEXT_REQ_MODE_SWITCH:
 		reason = "Interface Mode Switch";
 		break;
 	default:
 		reason = NULL;
 		dev_err(dev, "Invalid next-request: %u", bootrom->next_request);
 		break;
 	}

 	dev_err(dev, "Timed out waiting for %s from the Module\n", reason);

 	mutex_lock(&bootrom->mutex);
 	free_firmware(bootrom);
 	mutex_unlock(&bootrom->mutex);

 	/* TODO: Power-off Module ? */
 }

 static void gb_bootrom_set_timeout(struct gb_bootrom *bootrom,
 				   enum next_request_type next,
 				   unsigned long timeout)
 {
 	bootrom->next_request = next;
 	schedule_delayed_work(&bootrom->dwork, msecs_to_jiffies(timeout));
 }

 static void gb_bootrom_cancel_timeout(struct gb_bootrom *bootrom)
 {
 	cancel_delayed_work_sync(&bootrom->dwork);
 }

 /*
  * The es2 chip doesn't have VID/PID programmed into the hardware and we need to
  * hack that up to distinguish different modules and their firmware blobs.
  *
  * This fetches VID/PID (over bootrom protocol) for es2 chip only, when VID/PID
  * already sent during hotplug are 0.
  *
  * Otherwise, we keep intf->vendor_id/product_id same as what's passed
  * during hotplug.
  */
 static void bootrom_es2_fixup_vid_pid(struct gb_bootrom *bootrom)
 {
 	struct gb_bootrom_get_vid_pid_response response;
 	struct gb_connection *connection = bootrom->connection;
 	struct gb_interface *intf = connection->bundle->intf;
 	int ret;

 	if (!(intf->quirks & GB_INTERFACE_QUIRK_NO_GMP_IDS))
 		return;

 	ret = gb_operation_sync(connection, GB_BOOTROM_TYPE_GET_VID_PID,
 				NULL, 0, &response, sizeof(response));
 	if (ret) {
 		dev_err(&connection->bundle->dev,
 			"Bootrom get vid/pid operation failed (%d)\n", ret);
 		return;
 	}

 	/*
 	 * NOTE: This is hacked, so that the same values of VID/PID can be used
 	 * by next firmware level as well. The uevent for bootrom will still
 	 * have VID/PID as 0, though after this point the sysfs files will start
 	 * showing the updated values. But yeah, that's a bit racy as the same
 	 * sysfs files would be showing 0 before this point.
 	 */
 	intf->vendor_id = le32_to_cpu(response.vendor_id);
 	intf->product_id = le32_to_cpu(response.product_id);

 	dev_dbg(&connection->bundle->dev, "Bootrom got vid (0x%x)/pid (0x%x)\n",
 		intf->vendor_id, intf->product_id);
 }

 /* This returns path of the firmware blob on the disk */
 static int find_firmware(struct gb_bootrom *bootrom, u8 stage)
 {
 	struct gb_connection *connection = bootrom->connection;
 	struct gb_interface *intf = connection->bundle->intf;
 	char firmware_name[49];
 	int rc;

 	/* Already have a firmware, free it */
 	free_firmware(bootrom);

 	/* Bootrom protocol is only supported for loading Stage 2 firmware */
 	if (stage != 2) {
 		dev_err(&connection->bundle->dev, "Invalid boot stage: %u\n",
 			stage);
 		return -EINVAL;
 	}

 	/*
 	 * Create firmware name
 	 *
 	 * XXX Name it properly..
 	 */
 	snprintf(firmware_name, sizeof(firmware_name),
 		 FW_NAME_PREFIX "%08x_%08x_%08x_%08x_s2l.tftf",
 		 intf->ddbl1_manufacturer_id, intf->ddbl1_product_id,
 		 intf->vendor_id, intf->product_id);

 	// FIXME:
 	// Turn to dev_dbg later after everyone has valid bootloaders with good
 	// ids, but leave this as dev_info for now to make it easier to track
 	// down "empty" vid/pid modules.
 	dev_info(&connection->bundle->dev, "Firmware file '%s' requested\n",
 		 firmware_name);

 	rc = request_firmware(&bootrom->fw, firmware_name,
 			      &connection->bundle->dev);
 	if (rc) {
 		dev_err(&connection->bundle->dev,
 			"failed to find %s firmware (%d)\n", firmware_name, rc);
 	}

 	return rc;
 }

 static int gb_bootrom_firmware_size_request(struct gb_operation *op)
 {
 	struct gb_bootrom *bootrom = gb_connection_get_data(op->connection);
 	struct gb_bootrom_firmware_size_request *size_request =
 		op->request->payload;
 	struct gb_bootrom_firmware_size_response *size_response;
 	struct device *dev = &op->connection->bundle->dev;
 	int ret;

 	/* Disable timeouts */
 	gb_bootrom_cancel_timeout(bootrom);

 	if (op->request->payload_size != sizeof(*size_request)) {
 		dev_err(dev, "%s: illegal size of firmware size request (%zu != %zu)\n",
 			__func__, op->request->payload_size,
 			sizeof(*size_request));
 		ret = -EINVAL;
 		goto queue_work;
 	}

 	mutex_lock(&bootrom->mutex);

 	ret = find_firmware(bootrom, size_request->stage);
 	if (ret)
 		goto unlock;

 	if (!gb_operation_response_alloc(op, sizeof(*size_response),
 					 GFP_KERNEL)) {
 		dev_err(dev, "%s: error allocating response\n", __func__);
 		free_firmware(bootrom);
 		ret = -ENOMEM;
 		goto unlock;
 	}

 	size_response = op->response->payload;
 	size_response->size = cpu_to_le32(bootrom->fw->size);

 	dev_dbg(dev, "%s: firmware size %d bytes\n",
 		__func__, size_response->size);

 unlock:
 	mutex_unlock(&bootrom->mutex);

 queue_work:
 	if (!ret) {
 		/* Refresh timeout */
 		gb_bootrom_set_timeout(bootrom, NEXT_REQ_GET_FIRMWARE,
 				       NEXT_REQ_TIMEOUT_MS);
 	}

 	return ret;
 }

 static int gb_bootrom_get_firmware(struct gb_operation *op)
 {
 	struct gb_bootrom *bootrom = gb_connection_get_data(op->connection);
 	const struct firmware *fw;
 	struct gb_bootrom_get_firmware_request *firmware_request;
 	struct device *dev = &op->connection->bundle->dev;
 	unsigned int offset, size;
 	enum next_request_type next_request;
 	u8 *firmware_response;
 	int ret = 0;

 	/* Disable timeouts */
 	gb_bootrom_cancel_timeout(bootrom);

 	if (op->request->payload_size != sizeof(*firmware_request)) {
 		dev_err(dev, "%s: Illegal size of get firmware request (%zu %zu)\n",
 			__func__, op->request->payload_size,
 			sizeof(*firmware_request));
 		ret = -EINVAL;
 		goto queue_work;
 	}

 	mutex_lock(&bootrom->mutex);

 	fw = bootrom->fw;
 	if (!fw) {
 		dev_err(dev, "%s: firmware not available\n", __func__);
 		ret = -EINVAL;
 		goto unlock;
 	}

 	firmware_request = op->request->payload;
 	offset = le32_to_cpu(firmware_request->offset);
 	size = le32_to_cpu(firmware_request->size);

 	if (offset >= fw->size || size > fw->size - offset) {
 		dev_warn(dev, "bad firmware request (offs = %u, size = %u)\n",
 			 offset, size);
 		ret = -EINVAL;
 		goto unlock;
 	}

 	/* gb_bootrom_get_firmware_response contains only a byte array */
 	if (!gb_operation_response_alloc(op, size, GFP_KERNEL)) {
 		dev_err(dev, "%s: error allocating response\n", __func__);
 		ret = -ENOMEM;
 		goto unlock;
 	}

 	firmware_response = op->response->payload;
 	memcpy(firmware_response, fw->data + offset, size);

 	dev_dbg(dev, "responding with firmware (offs = %u, size = %u)\n",
 		offset, size);

 unlock:
 	mutex_unlock(&bootrom->mutex);

 queue_work:
 	/* Refresh timeout */
 	if (!ret && (offset + size == fw->size))
 		next_request = NEXT_REQ_READY_TO_BOOT;
 	else
 		next_request = NEXT_REQ_GET_FIRMWARE;

 	gb_bootrom_set_timeout(bootrom, next_request, NEXT_REQ_TIMEOUT_MS);

 	return ret;
 }

 static int gb_bootrom_ready_to_boot(struct gb_operation *op)
 {
 	struct gb_connection *connection = op->connection;
 	struct gb_bootrom *bootrom = gb_connection_get_data(connection);
 	struct gb_bootrom_ready_to_boot_request *rtb_request;
 	struct device *dev = &connection->bundle->dev;
 	u8 status;
 	int ret = 0;

 	/* Disable timeouts */
 	gb_bootrom_cancel_timeout(bootrom);

 	if (op->request->payload_size != sizeof(*rtb_request)) {
 		dev_err(dev, "%s: Illegal size of ready to boot request (%zu %zu)\n",
 			__func__, op->request->payload_size,
 			sizeof(*rtb_request));
 		ret = -EINVAL;
 		goto queue_work;
 	}

 	rtb_request = op->request->payload;
 	status = rtb_request->status;

 	/* Return error if the blob was invalid */
 	if (status == GB_BOOTROM_BOOT_STATUS_INVALID) {
 		ret = -EINVAL;
 		goto queue_work;
 	}

 	/*
 	 * XXX Should we return error for insecure firmware?
 	 */
 	dev_dbg(dev, "ready to boot: 0x%x, 0\n", status);

 queue_work:
 	/*
 	 * Refresh timeout, the Interface shall load the new personality and
 	 * send a new hotplug request, which shall get rid of the bootrom
 	 * connection. As that can take some time, increase the timeout a bit.
 	 */
 	gb_bootrom_set_timeout(bootrom, NEXT_REQ_MODE_SWITCH,
 			       MODE_SWITCH_TIMEOUT_MS);

 	return ret;
 }

 static int gb_bootrom_request_handler(struct gb_operation *op)
 {
 	u8 type = op->type;

 	switch (type) {
 	case GB_BOOTROM_TYPE_FIRMWARE_SIZE:
 		return gb_bootrom_firmware_size_request(op);
 	case GB_BOOTROM_TYPE_GET_FIRMWARE:
 		return gb_bootrom_get_firmware(op);
 	case GB_BOOTROM_TYPE_READY_TO_BOOT:
 		return gb_bootrom_ready_to_boot(op);
 	default:
 		dev_err(&op->connection->bundle->dev,
 			"unsupported request: %u\n", type);
 		return -EINVAL;
 	}
 }

 static int gb_bootrom_get_version(struct gb_bootrom *bootrom)
 {
 	struct gb_bundle *bundle = bootrom->connection->bundle;
 	struct gb_bootrom_version_request request;
 	struct gb_bootrom_version_response response;
 	int ret;

 	request.major = GB_BOOTROM_VERSION_MAJOR;
 	request.minor = GB_BOOTROM_VERSION_MINOR;

 	ret = gb_operation_sync(bootrom->connection,
 				GB_BOOTROM_TYPE_VERSION,
 				&request, sizeof(request), &response,
 				sizeof(response));
 	if (ret) {
 		dev_err(&bundle->dev,
 			"failed to get protocol version: %d\n",
 			ret);
 		return ret;
 	}

 	if (response.major > request.major) {
 		dev_err(&bundle->dev,
 			"unsupported major protocol version (%u > %u)\n",
 			response.major, request.major);
 		return -ENOTSUPP;
 	}

 	bootrom->protocol_major = response.major;
 	bootrom->protocol_minor = response.minor;

 	dev_dbg(&bundle->dev, "%s - %u.%u\n", __func__, response.major,
 		response.minor);

 	return 0;
 }

 static int gb_bootrom_probe(struct gb_bundle *bundle,
 			    const struct greybus_bundle_id *id)
 {
 	struct greybus_descriptor_cport *cport_desc;
 	struct gb_connection *connection;
 	struct gb_bootrom *bootrom;
 	int ret;

 	if (bundle->num_cports != 1)
 		return -ENODEV;

 	cport_desc = &bundle->cport_desc[0];
 	if (cport_desc->protocol_id != GREYBUS_PROTOCOL_BOOTROM)
 		return -ENODEV;

 	bootrom = kzalloc(sizeof(*bootrom), GFP_KERNEL);
 	if (!bootrom)
 		return -ENOMEM;

 	connection = gb_connection_create(bundle,
 					  le16_to_cpu(cport_desc->id),
 					  gb_bootrom_request_handler);
 	if (IS_ERR(connection)) {
 		ret = PTR_ERR(connection);
 		goto err_free_bootrom;
 	}

 	gb_connection_set_data(connection, bootrom);

 	bootrom->connection = connection;

 	mutex_init(&bootrom->mutex);
 	INIT_DELAYED_WORK(&bootrom->dwork, gb_bootrom_timedout);
 	greybus_set_drvdata(bundle, bootrom);

 	ret = gb_connection_enable_tx(connection);
 	if (ret)
 		goto err_connection_destroy;

 	ret = gb_bootrom_get_version(bootrom);
 	if (ret)
 		goto err_connection_disable;

 	bootrom_es2_fixup_vid_pid(bootrom);

 	ret = gb_connection_enable(connection);
 	if (ret)
 		goto err_connection_disable;

 	/* Refresh timeout */
 	gb_bootrom_set_timeout(bootrom, NEXT_REQ_FIRMWARE_SIZE,
 			       NEXT_REQ_TIMEOUT_MS);

 	/* Tell bootrom we're ready. */
 	ret = gb_operation_sync(connection, GB_BOOTROM_TYPE_AP_READY, NULL, 0,
 				NULL, 0);
 	if (ret) {
 		dev_err(&connection->bundle->dev,
 			"failed to send AP READY: %d\n", ret);
 		goto err_cancel_timeout;
 	}

 	dev_dbg(&bundle->dev, "AP_READY sent\n");

 	return 0;

 err_cancel_timeout:
 	gb_bootrom_cancel_timeout(bootrom);
 err_connection_disable:
 	gb_connection_disable(connection);
 err_connection_destroy:
 	gb_connection_destroy(connection);
 err_free_bootrom:
 	kfree(bootrom);

 	return ret;
 }

 static void gb_bootrom_disconnect(struct gb_bundle *bundle)
 {
 	struct gb_bootrom *bootrom = greybus_get_drvdata(bundle);

 	gb_connection_disable(bootrom->connection);

 	/* Disable timeouts */
 	gb_bootrom_cancel_timeout(bootrom);

 	/*
 	 * Release firmware:
 	 *
 	 * As the connection and the delayed work are already disabled, we don't
 	 * need to lock access to bootrom->fw here.
 	 */
 	free_firmware(bootrom);

 	gb_connection_destroy(bootrom->connection);
 	kfree(bootrom);
 }

 static const struct greybus_bundle_id gb_bootrom_id_table[] = {
 	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_BOOTROM) },
 	{ }
 };

 static struct greybus_driver gb_bootrom_driver = {
 	.name		= "bootrom",
 	.probe		= gb_bootrom_probe,
 	.disconnect	= gb_bootrom_disconnect,
 	.id_table	= gb_bootrom_id_table,
 };

 module_greybus_driver(gb_bootrom_driver);

 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	/*
	* BOOTROM Greybus driver.
	*
	* Copyright 2016 Google Inc.
	* Copyright 2016 Linaro Ltd.
	*/

	#include <linux/firmware.h>
	#include <linux/jiffies.h>
	#include <linux/mutex.h>
	#include <linux/workqueue.h>
	#include <linux/greybus.h>

	#include "firmware.h"

	/* Timeout, in jiffies, within which the next request must be received */
	#define NEXT_REQ_TIMEOUT_MS 1000

	/*
	* FIXME: Reduce this timeout once svc core handles parallel processing of
	* events from the SVC, which are handled sequentially today.
	*/
	#define MODE_SWITCH_TIMEOUT_MS 10000

	enum next_request_type {
	NEXT_REQ_FIRMWARE_SIZE,
	NEXT_REQ_GET_FIRMWARE,
	NEXT_REQ_READY_TO_BOOT,
	NEXT_REQ_MODE_SWITCH,
	};

	struct gb_bootrom {
	struct gb_connection *connection;
	const struct firmware *fw;
	u8 protocol_major;
	u8 protocol_minor;
	enum next_request_type next_request;
	struct delayed_work dwork;
	struct mutex mutex; /* Protects bootrom->fw */
	};

	static void free_firmware(struct gb_bootrom *bootrom)
	{
	if (!bootrom->fw)
	return;

	release_firmware(bootrom->fw);
	bootrom->fw = NULL;
	}

	static void gb_bootrom_timedout(struct work_struct *work)
	{
	struct delayed_work *dwork = to_delayed_work(work);
	struct gb_bootrom *bootrom = container_of(dwork,
	struct gb_bootrom, dwork);
	struct device *dev = &bootrom->connection->bundle->dev;
	const char *reason;

	switch (bootrom->next_request) {
	case NEXT_REQ_FIRMWARE_SIZE:
	reason = "Firmware Size Request";
	break;
	case NEXT_REQ_GET_FIRMWARE:
	reason = "Get Firmware Request";
	break;
	case NEXT_REQ_READY_TO_BOOT:
	reason = "Ready to Boot Request";
	break;
	case NEXT_REQ_MODE_SWITCH:
	reason = "Interface Mode Switch";
	break;
	default:
	reason = NULL;
	dev_err(dev, "Invalid next-request: %u", bootrom->next_request);
	break;
	}

	dev_err(dev, "Timed out waiting for %s from the Module\n", reason);

	mutex_lock(&bootrom->mutex);
	free_firmware(bootrom);
	mutex_unlock(&bootrom->mutex);

	/* TODO: Power-off Module ? */
	}

	static void gb_bootrom_set_timeout(struct gb_bootrom *bootrom,
	enum next_request_type next,
	unsigned long timeout)
	{
	bootrom->next_request = next;
	schedule_delayed_work(&bootrom->dwork, msecs_to_jiffies(timeout));
	}

	static void gb_bootrom_cancel_timeout(struct gb_bootrom *bootrom)
	{
	cancel_delayed_work_sync(&bootrom->dwork);
	}

	/*
	* The es2 chip doesn't have VID/PID programmed into the hardware and we need to
	* hack that up to distinguish different modules and their firmware blobs.
	*
	* This fetches VID/PID (over bootrom protocol) for es2 chip only, when VID/PID
	* already sent during hotplug are 0.
	*
	* Otherwise, we keep intf->vendor_id/product_id same as what's passed
	* during hotplug.
	*/
	static void bootrom_es2_fixup_vid_pid(struct gb_bootrom *bootrom)
	{
	struct gb_bootrom_get_vid_pid_response response;
	struct gb_connection *connection = bootrom->connection;
	struct gb_interface *intf = connection->bundle->intf;
	int ret;

	if (!(intf->quirks & GB_INTERFACE_QUIRK_NO_GMP_IDS))
	return;

	ret = gb_operation_sync(connection, GB_BOOTROM_TYPE_GET_VID_PID,
	NULL, 0, &response, sizeof(response));
	if (ret) {
	dev_err(&connection->bundle->dev,
	"Bootrom get vid/pid operation failed (%d)\n", ret);
	return;
	}

	/*
	* NOTE: This is hacked, so that the same values of VID/PID can be used
	* by next firmware level as well. The uevent for bootrom will still
	* have VID/PID as 0, though after this point the sysfs files will start
	* showing the updated values. But yeah, that's a bit racy as the same
	* sysfs files would be showing 0 before this point.
	*/
	intf->vendor_id = le32_to_cpu(response.vendor_id);
	intf->product_id = le32_to_cpu(response.product_id);

	dev_dbg(&connection->bundle->dev, "Bootrom got vid (0x%x)/pid (0x%x)\n",
	intf->vendor_id, intf->product_id);
	}

	/* This returns path of the firmware blob on the disk */
	static int find_firmware(struct gb_bootrom *bootrom, u8 stage)
	{
	struct gb_connection *connection = bootrom->connection;
	struct gb_interface *intf = connection->bundle->intf;
	char firmware_name[49];
	int rc;

	/* Already have a firmware, free it */
	free_firmware(bootrom);

	/* Bootrom protocol is only supported for loading Stage 2 firmware */
	if (stage != 2) {
	dev_err(&connection->bundle->dev, "Invalid boot stage: %u\n",
	stage);
	return -EINVAL;
	}

	/*
	* Create firmware name
	*
	* XXX Name it properly..
	*/
	snprintf(firmware_name, sizeof(firmware_name),
	FW_NAME_PREFIX "%08x_%08x_%08x_%08x_s2l.tftf",
	intf->ddbl1_manufacturer_id, intf->ddbl1_product_id,
	intf->vendor_id, intf->product_id);

	// FIXME:
	// Turn to dev_dbg later after everyone has valid bootloaders with good
	// ids, but leave this as dev_info for now to make it easier to track
	// down "empty" vid/pid modules.
	dev_info(&connection->bundle->dev, "Firmware file '%s' requested\n",
	firmware_name);

	rc = request_firmware(&bootrom->fw, firmware_name,
	&connection->bundle->dev);
	if (rc) {
	dev_err(&connection->bundle->dev,
	"failed to find %s firmware (%d)\n", firmware_name, rc);
	}

	return rc;
	}

	static int gb_bootrom_firmware_size_request(struct gb_operation *op)
	{
	struct gb_bootrom *bootrom = gb_connection_get_data(op->connection);
	struct gb_bootrom_firmware_size_request *size_request =
	op->request->payload;
	struct gb_bootrom_firmware_size_response *size_response;
	struct device *dev = &op->connection->bundle->dev;
	int ret;

	/* Disable timeouts */
	gb_bootrom_cancel_timeout(bootrom);

	if (op->request->payload_size != sizeof(*size_request)) {
	dev_err(dev, "%s: illegal size of firmware size request (%zu != %zu)\n",
	__func__, op->request->payload_size,
	sizeof(*size_request));
	ret = -EINVAL;
	goto queue_work;
	}

	mutex_lock(&bootrom->mutex);

	ret = find_firmware(bootrom, size_request->stage);
	if (ret)
	goto unlock;

	if (!gb_operation_response_alloc(op, sizeof(*size_response),
	GFP_KERNEL)) {
	dev_err(dev, "%s: error allocating response\n", __func__);
	free_firmware(bootrom);
	ret = -ENOMEM;
	goto unlock;
	}

	size_response = op->response->payload;
	size_response->size = cpu_to_le32(bootrom->fw->size);

	dev_dbg(dev, "%s: firmware size %d bytes\n",
	__func__, size_response->size);

	unlock:
	mutex_unlock(&bootrom->mutex);

	queue_work:
	if (!ret) {
	/* Refresh timeout */
	gb_bootrom_set_timeout(bootrom, NEXT_REQ_GET_FIRMWARE,
	NEXT_REQ_TIMEOUT_MS);
	}

	return ret;
	}

	static int gb_bootrom_get_firmware(struct gb_operation *op)
	{
	struct gb_bootrom *bootrom = gb_connection_get_data(op->connection);
	const struct firmware *fw;
	struct gb_bootrom_get_firmware_request *firmware_request;
	struct device *dev = &op->connection->bundle->dev;
	unsigned int offset, size;
	enum next_request_type next_request;
	u8 *firmware_response;
	int ret = 0;

	/* Disable timeouts */
	gb_bootrom_cancel_timeout(bootrom);

	if (op->request->payload_size != sizeof(*firmware_request)) {
	dev_err(dev, "%s: Illegal size of get firmware request (%zu %zu)\n",
	__func__, op->request->payload_size,
	sizeof(*firmware_request));
	ret = -EINVAL;
	goto queue_work;
	}

	mutex_lock(&bootrom->mutex);

	fw = bootrom->fw;
	if (!fw) {
	dev_err(dev, "%s: firmware not available\n", __func__);
	ret = -EINVAL;
	goto unlock;
	}

	firmware_request = op->request->payload;
	offset = le32_to_cpu(firmware_request->offset);
	size = le32_to_cpu(firmware_request->size);

	if (offset >= fw->size \|\| size > fw->size - offset) {
	dev_warn(dev, "bad firmware request (offs = %u, size = %u)\n",
	offset, size);
	ret = -EINVAL;
	goto unlock;
	}

	/* gb_bootrom_get_firmware_response contains only a byte array */
	if (!gb_operation_response_alloc(op, size, GFP_KERNEL)) {
	dev_err(dev, "%s: error allocating response\n", __func__);
	ret = -ENOMEM;
	goto unlock;
	}

	firmware_response = op->response->payload;
	memcpy(firmware_response, fw->data + offset, size);

	dev_dbg(dev, "responding with firmware (offs = %u, size = %u)\n",
	offset, size);

	unlock:
	mutex_unlock(&bootrom->mutex);

	queue_work:
	/* Refresh timeout */
	if (!ret && (offset + size == fw->size))
	next_request = NEXT_REQ_READY_TO_BOOT;
	else
	next_request = NEXT_REQ_GET_FIRMWARE;

	gb_bootrom_set_timeout(bootrom, next_request, NEXT_REQ_TIMEOUT_MS);

	return ret;
	}

	static int gb_bootrom_ready_to_boot(struct gb_operation *op)
	{
	struct gb_connection *connection = op->connection;
	struct gb_bootrom *bootrom = gb_connection_get_data(connection);
	struct gb_bootrom_ready_to_boot_request *rtb_request;
	struct device *dev = &connection->bundle->dev;
	u8 status;
	int ret = 0;

	/* Disable timeouts */
	gb_bootrom_cancel_timeout(bootrom);

	if (op->request->payload_size != sizeof(*rtb_request)) {
	dev_err(dev, "%s: Illegal size of ready to boot request (%zu %zu)\n",
	__func__, op->request->payload_size,
	sizeof(*rtb_request));
	ret = -EINVAL;
	goto queue_work;
	}

	rtb_request = op->request->payload;
	status = rtb_request->status;

	/* Return error if the blob was invalid */
	if (status == GB_BOOTROM_BOOT_STATUS_INVALID) {
	ret = -EINVAL;
	goto queue_work;
	}

	/*
	* XXX Should we return error for insecure firmware?
	*/
	dev_dbg(dev, "ready to boot: 0x%x, 0\n", status);

	queue_work:
	/*
	* Refresh timeout, the Interface shall load the new personality and
	* send a new hotplug request, which shall get rid of the bootrom
	* connection. As that can take some time, increase the timeout a bit.
	*/
	gb_bootrom_set_timeout(bootrom, NEXT_REQ_MODE_SWITCH,
	MODE_SWITCH_TIMEOUT_MS);

	return ret;
	}

	static int gb_bootrom_request_handler(struct gb_operation *op)
	{
	u8 type = op->type;

	switch (type) {
	case GB_BOOTROM_TYPE_FIRMWARE_SIZE:
	return gb_bootrom_firmware_size_request(op);
	case GB_BOOTROM_TYPE_GET_FIRMWARE:
	return gb_bootrom_get_firmware(op);
	case GB_BOOTROM_TYPE_READY_TO_BOOT:
	return gb_bootrom_ready_to_boot(op);
	default:
	dev_err(&op->connection->bundle->dev,
	"unsupported request: %u\n", type);
	return -EINVAL;
	}
	}

	static int gb_bootrom_get_version(struct gb_bootrom *bootrom)
	{
	struct gb_bundle *bundle = bootrom->connection->bundle;
	struct gb_bootrom_version_request request;
	struct gb_bootrom_version_response response;
	int ret;

	request.major = GB_BOOTROM_VERSION_MAJOR;
	request.minor = GB_BOOTROM_VERSION_MINOR;

	ret = gb_operation_sync(bootrom->connection,
	GB_BOOTROM_TYPE_VERSION,
	&request, sizeof(request), &response,
	sizeof(response));
	if (ret) {
	dev_err(&bundle->dev,
	"failed to get protocol version: %d\n",
	ret);
	return ret;
	}

	if (response.major > request.major) {
	dev_err(&bundle->dev,
	"unsupported major protocol version (%u > %u)\n",
	response.major, request.major);
	return -ENOTSUPP;
	}

	bootrom->protocol_major = response.major;
	bootrom->protocol_minor = response.minor;

	dev_dbg(&bundle->dev, "%s - %u.%u\n", __func__, response.major,
	response.minor);

	return 0;
	}

	static int gb_bootrom_probe(struct gb_bundle *bundle,
	const struct greybus_bundle_id *id)
	{
	struct greybus_descriptor_cport *cport_desc;
	struct gb_connection *connection;
	struct gb_bootrom *bootrom;
	int ret;

	if (bundle->num_cports != 1)
	return -ENODEV;

	cport_desc = &bundle->cport_desc[0];
	if (cport_desc->protocol_id != GREYBUS_PROTOCOL_BOOTROM)
	return -ENODEV;

	bootrom = kzalloc(sizeof(*bootrom), GFP_KERNEL);
	if (!bootrom)
	return -ENOMEM;

	connection = gb_connection_create(bundle,
	le16_to_cpu(cport_desc->id),
	gb_bootrom_request_handler);
	if (IS_ERR(connection)) {
	ret = PTR_ERR(connection);
	goto err_free_bootrom;
	}

	gb_connection_set_data(connection, bootrom);

	bootrom->connection = connection;

	mutex_init(&bootrom->mutex);
	INIT_DELAYED_WORK(&bootrom->dwork, gb_bootrom_timedout);
	greybus_set_drvdata(bundle, bootrom);

	ret = gb_connection_enable_tx(connection);
	if (ret)
	goto err_connection_destroy;

	ret = gb_bootrom_get_version(bootrom);
	if (ret)
	goto err_connection_disable;

	bootrom_es2_fixup_vid_pid(bootrom);

	ret = gb_connection_enable(connection);
	if (ret)
	goto err_connection_disable;

	/* Refresh timeout */
	gb_bootrom_set_timeout(bootrom, NEXT_REQ_FIRMWARE_SIZE,
	NEXT_REQ_TIMEOUT_MS);

	/* Tell bootrom we're ready. */
	ret = gb_operation_sync(connection, GB_BOOTROM_TYPE_AP_READY, NULL, 0,
	NULL, 0);
	if (ret) {
	dev_err(&connection->bundle->dev,
	"failed to send AP READY: %d\n", ret);
	goto err_cancel_timeout;
	}

	dev_dbg(&bundle->dev, "AP_READY sent\n");

	return 0;

	err_cancel_timeout:
	gb_bootrom_cancel_timeout(bootrom);
	err_connection_disable:
	gb_connection_disable(connection);
	err_connection_destroy:
	gb_connection_destroy(connection);
	err_free_bootrom:
	kfree(bootrom);

	return ret;
	}

	static void gb_bootrom_disconnect(struct gb_bundle *bundle)
	{
	struct gb_bootrom *bootrom = greybus_get_drvdata(bundle);

	gb_connection_disable(bootrom->connection);

	/* Disable timeouts */
	gb_bootrom_cancel_timeout(bootrom);

	/*
	* Release firmware:
	*
	* As the connection and the delayed work are already disabled, we don't
	* need to lock access to bootrom->fw here.
	*/
	free_firmware(bootrom);

	gb_connection_destroy(bootrom->connection);
	kfree(bootrom);
	}

	static const struct greybus_bundle_id gb_bootrom_id_table[] = {
	{ GREYBUS_DEVICE_CLASS(GREYBUS_CLASS_BOOTROM) },
	{ }
	};

	static struct greybus_driver gb_bootrom_driver = {
	.name = "bootrom",
	.probe = gb_bootrom_probe,
	.disconnect = gb_bootrom_disconnect,
	.id_table = gb_bootrom_id_table,
	};

	module_greybus_driver(gb_bootrom_driver);

	MODULE_LICENSE("GPL v2");