platform/chrome: wilco_ec: Add property helper library

# SPDX-License-Identifier: GPL-2.0

wilco_ec-objs				:= core.o mailbox.o

wilco_ec-objs				:= core.o mailbox.o properties.o

obj-$(CONFIG_WILCO_EC)			+= wilco_ec.o

wilco_ec_debugfs-objs			:= debugfs.o

obj-$(CONFIG_WILCO_EC_DEBUGFS)		+= wilco_ec_debugfs.o

// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright 2019 Google LLC

 */

#include <linux/platform_data/wilco-ec.h>

#include <linux/string.h>

#include <linux/unaligned/le_memmove.h>

/* Operation code; what the EC should do with the property */

enum ec_property_op {

	EC_OP_GET = 0,

	EC_OP_SET = 1,

};

struct ec_property_request {

	u8 op; /* One of enum ec_property_op */

	u8 property_id[4]; /* The 32 bit PID is stored Little Endian */

	u8 length;

	u8 data[WILCO_EC_PROPERTY_MAX_SIZE];

} __packed;

struct ec_property_response {

	u8 reserved[2];

	u8 op; /* One of enum ec_property_op */

	u8 property_id[4]; /* The 32 bit PID is stored Little Endian */

	u8 length;

	u8 data[WILCO_EC_PROPERTY_MAX_SIZE];

} __packed;

static int send_property_msg(struct wilco_ec_device *ec,

			     struct ec_property_request *rq,

			     struct ec_property_response *rs)

{

	struct wilco_ec_message ec_msg;

	int ret;

	memset(&ec_msg, 0, sizeof(ec_msg));

	ec_msg.type = WILCO_EC_MSG_PROPERTY;

	ec_msg.request_data = rq;

	ec_msg.request_size = sizeof(*rq);

	ec_msg.response_data = rs;

	ec_msg.response_size = sizeof(*rs);

	ret = wilco_ec_mailbox(ec, &ec_msg);

	if (ret < 0)

		return ret;

	if (rs->op != rq->op)

		return -EBADMSG;

	if (memcmp(rq->property_id, rs->property_id, sizeof(rs->property_id)))

		return -EBADMSG;

	return 0;

}

int wilco_ec_get_property(struct wilco_ec_device *ec,

			  struct wilco_ec_property_msg *prop_msg)

{

	struct ec_property_request rq;

	struct ec_property_response rs;

	int ret;

	memset(&rq, 0, sizeof(rq));

	rq.op = EC_OP_GET;

	put_unaligned_le32(prop_msg->property_id, rq.property_id);

	ret = send_property_msg(ec, &rq, &rs);

	if (ret < 0)

		return ret;

	prop_msg->length = rs.length;

	memcpy(prop_msg->data, rs.data, rs.length);

	return 0;

}

EXPORT_SYMBOL_GPL(wilco_ec_get_property);

int wilco_ec_set_property(struct wilco_ec_device *ec,

			  struct wilco_ec_property_msg *prop_msg)

{

	struct ec_property_request rq;

	struct ec_property_response rs;

	int ret;

	memset(&rq, 0, sizeof(rq));

	rq.op = EC_OP_SET;

	put_unaligned_le32(prop_msg->property_id, rq.property_id);

	rq.length = prop_msg->length;

	memcpy(rq.data, prop_msg->data, prop_msg->length);

	ret = send_property_msg(ec, &rq, &rs);

	if (ret < 0)

		return ret;

	if (rs.length != prop_msg->length)

		return -EBADMSG;

	return 0;

}

EXPORT_SYMBOL_GPL(wilco_ec_set_property);

int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id,

			       u8 *val)

{

	struct wilco_ec_property_msg msg;

	int ret;

	msg.property_id = property_id;

	ret = wilco_ec_get_property(ec, &msg);

	if (ret < 0)

		return ret;

	if (msg.length != 1)

		return -EBADMSG;

	*val = msg.data[0];

	return 0;

}

EXPORT_SYMBOL_GPL(wilco_ec_get_byte_property);

int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id,

			       u8 val)

{

	struct wilco_ec_property_msg msg;

	msg.property_id = property_id;

	msg.data[0] = val;

	msg.length = 1;

	return wilco_ec_set_property(ec, &msg);

}

EXPORT_SYMBOL_GPL(wilco_ec_set_byte_property);

 */

int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg);

/*

 * A Property is typically a data item that is stored to NVRAM

 * by the EC. Each of these data items has an index associated

 * with it, known as the Property ID (PID). Properties may have

 * variable lengths, up to a max of WILCO_EC_PROPERTY_MAX_SIZE

 * bytes. Properties can be simple integers, or they may be more

 * complex binary data.

 */

#define WILCO_EC_PROPERTY_MAX_SIZE	4

/**

 * struct ec_property_set_msg - Message to get or set a property.

 * @property_id: Which property to get or set.

 * @length: Number of bytes of |data| that are used.

 * @data: Actual property data.

 */

struct wilco_ec_property_msg {

	u32 property_id;

	int length;

	u8 data[WILCO_EC_PROPERTY_MAX_SIZE];

};

/**

 * wilco_ec_get_property() - Retrieve a property from the EC.

 * @ec: Embedded Controller device.

 * @prop_msg: Message for request and response.

 *

 * The property_id field of |prop_msg| should be filled before calling this

 * function. The result will be stored in the data and length fields.

 *

 * Return: 0 on success, negative error code on failure.

 */

int wilco_ec_get_property(struct wilco_ec_device *ec,

			  struct wilco_ec_property_msg *prop_msg);

/**

 * wilco_ec_set_property() - Store a property on the EC.

 * @ec: Embedded Controller device.

 * @prop_msg: Message for request and response.

 *

 * The property_id, length, and data fields of |prop_msg| should be

 * filled before calling this function.

 *

 * Return: 0 on success, negative error code on failure.

 */

int wilco_ec_set_property(struct wilco_ec_device *ec,

			  struct wilco_ec_property_msg *prop_msg);

/**

 * wilco_ec_get_byte_property() - Retrieve a byte-size property from the EC.

 * @ec: Embedded Controller device.

 * @property_id: Which property to retrieve.

 * @val: The result value, will be filled by this function.

 *

 * Return: 0 on success, negative error code on failure.

 */

int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id,

			       u8 *val);

/**

 * wilco_ec_get_byte_property() - Store a byte-size property on the EC.

 * @ec: Embedded Controller device.

 * @property_id: Which property to store.

 * @val: Value to store.

 *

 * Return: 0 on success, negative error code on failure.

 */

int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id,

			       u8 val);

#endif /* WILCO_EC_H */