drivers/soc/qcom/smd-rpm.c

   1 /*
   2  * Copyright (c) 2015, Sony Mobile Communications AB.
   3  * Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 and
   7  * only version 2 as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/of_platform.h>
  18 #include <linux/io.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/slab.h>
  21
  22 #include <linux/soc/qcom/smd.h>
  23 #include <linux/soc/qcom/smd-rpm.h>
  24
  25 #define RPM_REQUEST_TIMEOUT     (5 * HZ)
  26
  27 /**
  28  * struct qcom_smd_rpm - state of the rpm device driver
  29  * @rpm_channel:        reference to the smd channel
  30  * @ack:                completion for acks
  31  * @lock:               mutual exclusion around the send/complete pair
  32  * @ack_status:         result of the rpm request
  33  */
  34 struct qcom_smd_rpm {
  35         struct qcom_smd_channel *rpm_channel;
  36
  37         struct completion ack;
  38         struct mutex lock;
  39         int ack_status;
  40 };
  41
  42 /**
  43  * struct qcom_rpm_header - header for all rpm requests and responses
  44  * @service_type:       identifier of the service
  45  * @length:             length of the payload
  46  */
  47 struct qcom_rpm_header {
  48         u32 service_type;
  49         u32 length;
  50 };
  51
  52 /**
  53  * struct qcom_rpm_request - request message to the rpm
  54  * @msg_id:     identifier of the outgoing message
  55  * @flags:      active/sleep state flags
  56  * @type:       resource type
  57  * @id:         resource id
  58  * @data_len:   length of the payload following this header
  59  */
  60 struct qcom_rpm_request {
  61         u32 msg_id;
  62         u32 flags;
  63         u32 type;
  64         u32 id;
  65         u32 data_len;
  66 };
  67
  68 /**
  69  * struct qcom_rpm_message - response message from the rpm
  70  * @msg_type:   indicator of the type of message
  71  * @length:     the size of this message, including the message header
  72  * @msg_id:     message id
  73  * @message:    textual message from the rpm
  74  *
  75  * Multiple of these messages can be stacked in an rpm message.
  76  */
  77 struct qcom_rpm_message {
  78         u32 msg_type;
  79         u32 length;
  80         union {
  81                 u32 msg_id;
  82                 u8 message[0];
  83         };
  84 };
  85
  86 #define RPM_SERVICE_TYPE_REQUEST        0x00716572 /* "req\0" */
  87
  88 #define RPM_MSG_TYPE_ERR                0x00727265 /* "err\0" */
  89 #define RPM_MSG_TYPE_MSG_ID             0x2367736d /* "msg#" */
  90
  91 /**
  92  * qcom_rpm_smd_write - write @buf to @type:@id
  93  * @rpm:        rpm handle
  94  * @type:       resource type
  95  * @id:         resource identifier
  96  * @buf:        the data to be written
  97  * @count:      number of bytes in @buf
  98  */
  99 int qcom_rpm_smd_write(struct qcom_smd_rpm *rpm,
 100                        int state,
 101                        u32 type, u32 id,
 102                        void *buf,
 103                        size_t count)
 104 {
 105         static unsigned msg_id = 1;
 106         int left;
 107         int ret;
 108         struct {
 109                 struct qcom_rpm_header hdr;
 110                 struct qcom_rpm_request req;
 111                 u8 payload[];
 112         } *pkt;
 113         size_t size = sizeof(*pkt) + count;
 114
 115         /* SMD packets to the RPM may not exceed 256 bytes */
 116         if (WARN_ON(size >= 256))
 117                 return -EINVAL;
 118
 119         pkt = kmalloc(size, GFP_KERNEL);
 120         if (!pkt)
 121                 return -ENOMEM;
 122
 123         mutex_lock(&rpm->lock);
 124
 125         pkt->hdr.service_type = RPM_SERVICE_TYPE_REQUEST;
 126         pkt->hdr.length = sizeof(struct qcom_rpm_request) + count;
 127
 128         pkt->req.msg_id = msg_id++;
 129         pkt->req.flags = BIT(state);
 130         pkt->req.type = type;
 131         pkt->req.id = id;
 132         pkt->req.data_len = count;
 133         memcpy(pkt->payload, buf, count);
 134
 135         ret = qcom_smd_send(rpm->rpm_channel, pkt, sizeof(*pkt));
 136         if (ret)
 137                 goto out;
 138
 139         left = wait_for_completion_timeout(&rpm->ack, RPM_REQUEST_TIMEOUT);
 140         if (!left)
 141                 ret = -ETIMEDOUT;
 142         else
 143                 ret = rpm->ack_status;
 144
 145 out:
 146         kfree(pkt);
 147         mutex_unlock(&rpm->lock);
 148         return ret;
 149 }
 150 EXPORT_SYMBOL(qcom_rpm_smd_write);
 151
 152 static int qcom_smd_rpm_callback(struct qcom_smd_device *qsdev,
 153                                  const void *data,
 154                                  size_t count)
 155 {
 156         const struct qcom_rpm_header *hdr = data;
 157         const struct qcom_rpm_message *msg;
 158         struct qcom_smd_rpm *rpm = dev_get_drvdata(&qsdev->dev);
 159         const u8 *buf = data + sizeof(struct qcom_rpm_header);
 160         const u8 *end = buf + hdr->length;
 161         char msgbuf[32];
 162         int status = 0;
 163         u32 len;
 164
 165         if (hdr->service_type != RPM_SERVICE_TYPE_REQUEST ||
 166             hdr->length < sizeof(struct qcom_rpm_message)) {
 167                 dev_err(&qsdev->dev, "invalid request\n");
 168                 return 0;
 169         }
 170
 171         while (buf < end) {
 172                 msg = (struct qcom_rpm_message *)buf;
 173                 switch (msg->msg_type) {
 174                 case RPM_MSG_TYPE_MSG_ID:
 175                         break;
 176                 case RPM_MSG_TYPE_ERR:
 177                         len = min_t(u32, ALIGN(msg->length, 4), sizeof(msgbuf));
 178                         memcpy_fromio(msgbuf, msg->message, len);
 179                         msgbuf[len - 1] = 0;
 180
 181                         if (!strcmp(msgbuf, "resource does not exist"))
 182                                 status = -ENXIO;
 183                         else
 184                                 status = -EINVAL;
 185                         break;
 186                 }
 187
 188                 buf = PTR_ALIGN(buf + 2 * sizeof(u32) + msg->length, 4);
 189         }
 190
 191         rpm->ack_status = status;
 192         complete(&rpm->ack);
 193         return 0;
 194 }
 195
 196 static int qcom_smd_rpm_probe(struct qcom_smd_device *sdev)
 197 {
 198         struct qcom_smd_rpm *rpm;
 199
 200         rpm = devm_kzalloc(&sdev->dev, sizeof(*rpm), GFP_KERNEL);
 201         if (!rpm)
 202                 return -ENOMEM;
 203
 204         mutex_init(&rpm->lock);
 205         init_completion(&rpm->ack);
 206
 207         rpm->rpm_channel = sdev->channel;
 208
 209         dev_set_drvdata(&sdev->dev, rpm);
 210
 211         return of_platform_populate(sdev->dev.of_node, NULL, NULL, &sdev->dev);
 212 }
 213
 214 static void qcom_smd_rpm_remove(struct qcom_smd_device *sdev)
 215 {
 216         of_platform_depopulate(&sdev->dev);
 217 }
 218
 219 static const struct of_device_id qcom_smd_rpm_of_match[] = {
 220         { .compatible = "qcom,rpm-msm8974" },
 221         {}
 222 };
 223 MODULE_DEVICE_TABLE(of, qcom_smd_rpm_of_match);
 224
 225 static struct qcom_smd_driver qcom_smd_rpm_driver = {
 226         .probe = qcom_smd_rpm_probe,
 227         .remove = qcom_smd_rpm_remove,
 228         .callback = qcom_smd_rpm_callback,
 229         .driver  = {
 230                 .name  = "qcom_smd_rpm",
 231                 .owner = THIS_MODULE,
 232                 .of_match_table = qcom_smd_rpm_of_match,
 233         },
 234 };
 235
 236 static int __init qcom_smd_rpm_init(void)
 237 {
 238         return qcom_smd_driver_register(&qcom_smd_rpm_driver);
 239 }
 240 arch_initcall(qcom_smd_rpm_init);
 241
 242 static void __exit qcom_smd_rpm_exit(void)
 243 {
 244         qcom_smd_driver_unregister(&qcom_smd_rpm_driver);
 245 }
 246 module_exit(qcom_smd_rpm_exit);
 247
 248 MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@sonymobile.com>");
 249 MODULE_DESCRIPTION("Qualcomm SMD backed RPM driver");
 250 MODULE_LICENSE("GPL v2");