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 */
qcom_mhi_qrtr_dl_callback(struct mhi_device * mhi_dev,struct mhi_result * mhi_res)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 */
qcom_mhi_qrtr_ul_callback(struct mhi_device * mhi_dev,struct mhi_result * mhi_res)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 */
qcom_mhi_qrtr_send(struct qrtr_endpoint * ep,struct sk_buff * skb)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 
qcom_mhi_qrtr_probe(struct mhi_device * mhi_dev,const struct mhi_device_id * id)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 
qcom_mhi_qrtr_remove(struct mhi_device * mhi_dev)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");
136