1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright 2019 Google LLC
4  */
5 
6 #include <linux/errno.h>
7 #include <linux/export.h>
8 #include <linux/platform_data/wilco-ec.h>
9 #include <linux/string.h>
10 #include <linux/types.h>
11 #include <asm/unaligned.h>
12 
13 /* Operation code; what the EC should do with the property */
14 enum ec_property_op {
15 	EC_OP_GET = 0,
16 	EC_OP_SET = 1,
17 };
18 
19 struct ec_property_request {
20 	u8 op; /* One of enum ec_property_op */
21 	u8 property_id[4]; /* The 32 bit PID is stored Little Endian */
22 	u8 length;
23 	u8 data[WILCO_EC_PROPERTY_MAX_SIZE];
24 } __packed;
25 
26 struct ec_property_response {
27 	u8 reserved[2];
28 	u8 op; /* One of enum ec_property_op */
29 	u8 property_id[4]; /* The 32 bit PID is stored Little Endian */
30 	u8 length;
31 	u8 data[WILCO_EC_PROPERTY_MAX_SIZE];
32 } __packed;
33 
34 static int send_property_msg(struct wilco_ec_device *ec,
35 			     struct ec_property_request *rq,
36 			     struct ec_property_response *rs)
37 {
38 	struct wilco_ec_message ec_msg;
39 	int ret;
40 
41 	memset(&ec_msg, 0, sizeof(ec_msg));
42 	ec_msg.type = WILCO_EC_MSG_PROPERTY;
43 	ec_msg.request_data = rq;
44 	ec_msg.request_size = sizeof(*rq);
45 	ec_msg.response_data = rs;
46 	ec_msg.response_size = sizeof(*rs);
47 
48 	ret = wilco_ec_mailbox(ec, &ec_msg);
49 	if (ret < 0)
50 		return ret;
51 	if (rs->op != rq->op)
52 		return -EBADMSG;
53 	if (memcmp(rq->property_id, rs->property_id, sizeof(rs->property_id)))
54 		return -EBADMSG;
55 
56 	return 0;
57 }
58 
59 int wilco_ec_get_property(struct wilco_ec_device *ec,
60 			  struct wilco_ec_property_msg *prop_msg)
61 {
62 	struct ec_property_request rq;
63 	struct ec_property_response rs;
64 	int ret;
65 
66 	memset(&rq, 0, sizeof(rq));
67 	rq.op = EC_OP_GET;
68 	put_unaligned_le32(prop_msg->property_id, rq.property_id);
69 
70 	ret = send_property_msg(ec, &rq, &rs);
71 	if (ret < 0)
72 		return ret;
73 
74 	prop_msg->length = rs.length;
75 	memcpy(prop_msg->data, rs.data, rs.length);
76 
77 	return 0;
78 }
79 EXPORT_SYMBOL_GPL(wilco_ec_get_property);
80 
81 int wilco_ec_set_property(struct wilco_ec_device *ec,
82 			  struct wilco_ec_property_msg *prop_msg)
83 {
84 	struct ec_property_request rq;
85 	struct ec_property_response rs;
86 	int ret;
87 
88 	memset(&rq, 0, sizeof(rq));
89 	rq.op = EC_OP_SET;
90 	put_unaligned_le32(prop_msg->property_id, rq.property_id);
91 	rq.length = prop_msg->length;
92 	memcpy(rq.data, prop_msg->data, prop_msg->length);
93 
94 	ret = send_property_msg(ec, &rq, &rs);
95 	if (ret < 0)
96 		return ret;
97 	if (rs.length != prop_msg->length)
98 		return -EBADMSG;
99 
100 	return 0;
101 }
102 EXPORT_SYMBOL_GPL(wilco_ec_set_property);
103 
104 int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id,
105 			       u8 *val)
106 {
107 	struct wilco_ec_property_msg msg;
108 	int ret;
109 
110 	msg.property_id = property_id;
111 
112 	ret = wilco_ec_get_property(ec, &msg);
113 	if (ret < 0)
114 		return ret;
115 	if (msg.length != 1)
116 		return -EBADMSG;
117 
118 	*val = msg.data[0];
119 
120 	return 0;
121 }
122 EXPORT_SYMBOL_GPL(wilco_ec_get_byte_property);
123 
124 int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id,
125 			       u8 val)
126 {
127 	struct wilco_ec_property_msg msg;
128 
129 	msg.property_id = property_id;
130 	msg.data[0] = val;
131 	msg.length = 1;
132 
133 	return wilco_ec_set_property(ec, &msg);
134 }
135 EXPORT_SYMBOL_GPL(wilco_ec_set_byte_property);
136