net/qrtr/mhi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
   4  */
   5
   6 #include <linux/mhi.h>
   7 #include <linux/mod_devicetable.h>
   8 #include <linux/module.h>
   9 #include <linux/skbuff.h>
  10 #include <net/sock.h>
  11
  12 #include "qrtr.h"
  13
  14 struct qrtr_mhi_dev {
  15         struct qrtr_endpoint ep;
  16         struct mhi_device *mhi_dev;
  17         struct device *dev;
  18 };
  19
  20 /* From MHI to QRTR */
  21 static void qcom_mhi_qrtr_dl_callback(struct mhi_device *mhi_dev,
  22                                       struct mhi_result *mhi_res)
  23 {
  24         struct qrtr_mhi_dev *qdev = dev_get_drvdata(&mhi_dev->dev);
  25         int rc;
  26
  27         if (!qdev || mhi_res->transaction_status)
  28                 return;
  29
  30         rc = qrtr_endpoint_post(&qdev->ep, mhi_res->buf_addr,
  31                                 mhi_res->bytes_xferd);
  32         if (rc == -EINVAL)
  33                 dev_err(qdev->dev, "invalid ipcrouter packet\n");
  34 }
  35
  36 /* From QRTR to MHI */
  37 static void qcom_mhi_qrtr_ul_callback(struct mhi_device *mhi_dev,
  38                                       struct mhi_result *mhi_res)
  39 {
  40         struct sk_buff *skb = mhi_res->buf_addr;
  41
  42         if (skb->sk)
  43                 sock_put(skb->sk);
  44         consume_skb(skb);
  45 }
  46
  47 /* Send data over MHI */
  48 static int qcom_mhi_qrtr_send(struct qrtr_endpoint *ep, struct sk_buff *skb)
  49 {
  50         struct qrtr_mhi_dev *qdev = container_of(ep, struct qrtr_mhi_dev, ep);
  51         int rc;
  52
  53         if (skb->sk)
  54                 sock_hold(skb->sk);
  55
  56         rc = skb_linearize(skb);
  57         if (rc)
  58                 goto free_skb;
  59
  60         rc = mhi_queue_skb(qdev->mhi_dev, DMA_TO_DEVICE, skb, skb->len,
  61                            MHI_EOT);
  62         if (rc)
  63                 goto free_skb;
  64
  65         return rc;
  66
  67 free_skb:
  68         if (skb->sk)
  69                 sock_put(skb->sk);
  70         kfree_skb(skb);
  71
  72         return rc;
  73 }
  74
  75 static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev,
  76                                const struct mhi_device_id *id)
  77 {
  78         struct qrtr_mhi_dev *qdev;
  79         int rc;
  80
  81         /* start channels */
  82         rc = mhi_prepare_for_transfer(mhi_dev);
  83         if (rc)
  84                 return rc;
  85
  86         qdev = devm_kzalloc(&mhi_dev->dev, sizeof(*qdev), GFP_KERNEL);
  87         if (!qdev)
  88                 return -ENOMEM;
  89
  90         qdev->mhi_dev = mhi_dev;
  91         qdev->dev = &mhi_dev->dev;
  92         qdev->ep.xmit = qcom_mhi_qrtr_send;
  93
  94         dev_set_drvdata(&mhi_dev->dev, qdev);
  95         rc = qrtr_endpoint_register(&qdev->ep, QRTR_EP_NID_AUTO);
  96         if (rc)
  97                 return rc;
  98
  99         dev_dbg(qdev->dev, "Qualcomm MHI QRTR driver probed\n");
 100
 101         return 0;
 102 }
 103
 104 static void qcom_mhi_qrtr_remove(struct mhi_device *mhi_dev)
 105 {
 106         struct qrtr_mhi_dev *qdev = dev_get_drvdata(&mhi_dev->dev);
 107
 108         qrtr_endpoint_unregister(&qdev->ep);
 109         mhi_unprepare_from_transfer(mhi_dev);
 110         dev_set_drvdata(&mhi_dev->dev, NULL);
 111 }
 112
 113 static const struct mhi_device_id qcom_mhi_qrtr_id_table[] = {
 114         { .chan = "IPCR" },
 115         {}
 116 };
 117 MODULE_DEVICE_TABLE(mhi, qcom_mhi_qrtr_id_table);
 118
 119 static struct mhi_driver qcom_mhi_qrtr_driver = {
 120         .probe = qcom_mhi_qrtr_probe,
 121         .remove = qcom_mhi_qrtr_remove,
 122         .dl_xfer_cb = qcom_mhi_qrtr_dl_callback,
 123         .ul_xfer_cb = qcom_mhi_qrtr_ul_callback,
 124         .id_table = qcom_mhi_qrtr_id_table,
 125         .driver = {
 126                 .name = "qcom_mhi_qrtr",
 127         },
 128 };
 129
 130 module_mhi_driver(qcom_mhi_qrtr_driver);
 131
 132 MODULE_AUTHOR("Chris Lew <clew@codeaurora.org>");
 133 MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
 134 MODULE_DESCRIPTION("Qualcomm IPC-Router MHI interface driver");
 135 MODULE_LICENSE("GPL v2");