drivers/platform/chrome/wilco_ec/properties.c

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