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
 14struct 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 */
 21static 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 && mhi_res->transaction_status != -ENOTCONN))
 28		return;
 29
 30	/* Channel got reset. So just free the buffer */
 31	if (mhi_res->transaction_status == -ENOTCONN) {
 32		devm_kfree(&mhi_dev->dev, mhi_res->buf_addr);
 33		return;
 34	}
 35
 36	rc = qrtr_endpoint_post(&qdev->ep, mhi_res->buf_addr,
 37				mhi_res->bytes_xferd);
 38	if (rc == -EINVAL)
 39		dev_err(qdev->dev, "invalid ipcrouter packet\n");
 40
 41	/* Done with the buffer, now recycle it for future use */
 42	rc = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, mhi_res->buf_addr,
 43			   mhi_dev->mhi_cntrl->buffer_len, MHI_EOT);
 44	if (rc)
 45		dev_err(&mhi_dev->dev, "Failed to recycle the buffer: %d\n", rc);
 46}
 47
 48/* From QRTR to MHI */
 49static void qcom_mhi_qrtr_ul_callback(struct mhi_device *mhi_dev,
 50				      struct mhi_result *mhi_res)
 51{
 52	struct sk_buff *skb = mhi_res->buf_addr;
 53
 54	if (skb->sk)
 55		sock_put(skb->sk);
 56	consume_skb(skb);
 57}
 58
 59/* Send data over MHI */
 60static int qcom_mhi_qrtr_send(struct qrtr_endpoint *ep, struct sk_buff *skb)
 61{
 62	struct qrtr_mhi_dev *qdev = container_of(ep, struct qrtr_mhi_dev, ep);
 63	int rc;
 64
 65	if (skb->sk)
 66		sock_hold(skb->sk);
 67
 68	rc = skb_linearize(skb);
 69	if (rc)
 70		goto free_skb;
 71
 72	rc = mhi_queue_skb(qdev->mhi_dev, DMA_TO_DEVICE, skb, skb->len,
 73			   MHI_EOT);
 74	if (rc)
 75		goto free_skb;
 76
 77	return rc;
 78
 79free_skb:
 80	if (skb->sk)
 81		sock_put(skb->sk);
 82	kfree_skb(skb);
 83
 84	return rc;
 85}
 86
 87static int qcom_mhi_qrtr_queue_dl_buffers(struct mhi_device *mhi_dev)
 88{
 89	u32 free_desc;
 90	void *buf;
 91	int ret;
 92
 93	free_desc = mhi_get_free_desc_count(mhi_dev, DMA_FROM_DEVICE);
 94	while (free_desc--) {
 95		buf = devm_kmalloc(&mhi_dev->dev, mhi_dev->mhi_cntrl->buffer_len, GFP_KERNEL);
 96		if (!buf)
 97			return -ENOMEM;
 98
 99		ret = mhi_queue_buf(mhi_dev, DMA_FROM_DEVICE, buf, mhi_dev->mhi_cntrl->buffer_len,
100				    MHI_EOT);
101		if (ret) {
102			dev_err(&mhi_dev->dev, "Failed to queue buffer: %d\n", ret);
103			return ret;
104		}
105	}
106
107	return 0;
108}
109
110static int qcom_mhi_qrtr_probe(struct mhi_device *mhi_dev,
111			       const struct mhi_device_id *id)
112{
113	struct qrtr_mhi_dev *qdev;
114	int rc;
115
116	qdev = devm_kzalloc(&mhi_dev->dev, sizeof(*qdev), GFP_KERNEL);
117	if (!qdev)
118		return -ENOMEM;
119
120	qdev->mhi_dev = mhi_dev;
121	qdev->dev = &mhi_dev->dev;
122	qdev->ep.xmit = qcom_mhi_qrtr_send;
123
124	dev_set_drvdata(&mhi_dev->dev, qdev);
125
126	/* start channels */
127	rc = mhi_prepare_for_transfer(mhi_dev);
128	if (rc)
129		return rc;
130
131	rc = qrtr_endpoint_register(&qdev->ep, QRTR_EP_NID_AUTO);
132	if (rc)
133		goto err_unprepare;
134
135	rc = qcom_mhi_qrtr_queue_dl_buffers(mhi_dev);
136	if (rc)
137		goto err_unregister;
138
139	dev_dbg(qdev->dev, "Qualcomm MHI QRTR driver probed\n");
140
141	return 0;
142
143err_unregister:
144	qrtr_endpoint_unregister(&qdev->ep);
145err_unprepare:
146	mhi_unprepare_from_transfer(mhi_dev);
147
148	return rc;
149}
150
151static void qcom_mhi_qrtr_remove(struct mhi_device *mhi_dev)
152{
153	struct qrtr_mhi_dev *qdev = dev_get_drvdata(&mhi_dev->dev);
154
155	qrtr_endpoint_unregister(&qdev->ep);
156	mhi_unprepare_from_transfer(mhi_dev);
157	dev_set_drvdata(&mhi_dev->dev, NULL);
158}
159
160static const struct mhi_device_id qcom_mhi_qrtr_id_table[] = {
161	{ .chan = "IPCR" },
162	{}
163};
164MODULE_DEVICE_TABLE(mhi, qcom_mhi_qrtr_id_table);
165
166static int __maybe_unused qcom_mhi_qrtr_pm_suspend_late(struct device *dev)
167{
168	struct mhi_device *mhi_dev = container_of(dev, struct mhi_device, dev);
169	enum mhi_state state;
170
171	state = mhi_get_mhi_state(mhi_dev->mhi_cntrl);
172	/*
173	 * If the device is in suspend state, then no need for the
174	 * client driver to unprepare the channels.
175	 */
176	if (state == MHI_STATE_M3)
177		return 0;
178
179	mhi_unprepare_from_transfer(mhi_dev);
180
181	return 0;
182}
183
184static int __maybe_unused qcom_mhi_qrtr_pm_resume_early(struct device *dev)
185{
186	struct mhi_device *mhi_dev = container_of(dev, struct mhi_device, dev);
187	enum mhi_state state;
188	int rc;
189
190	state = mhi_get_mhi_state(mhi_dev->mhi_cntrl);
191	/*
192	 * If the device is in suspend state, we won't unprepare channels
193	 * in suspend callback, therefore no need to prepare channels when
194	 * resume.
195	 */
196	if (state == MHI_STATE_M3)
197		return 0;
198
199	rc = mhi_prepare_for_transfer(mhi_dev);
200	if (rc) {
201		dev_err(dev, "failed to prepare for autoqueue transfer %d\n", rc);
202		return rc;
203	}
204
205	return qcom_mhi_qrtr_queue_dl_buffers(mhi_dev);
206}
207
208static const struct dev_pm_ops qcom_mhi_qrtr_pm_ops = {
209	SET_LATE_SYSTEM_SLEEP_PM_OPS(qcom_mhi_qrtr_pm_suspend_late,
210				     qcom_mhi_qrtr_pm_resume_early)
211};
212
213static struct mhi_driver qcom_mhi_qrtr_driver = {
214	.probe = qcom_mhi_qrtr_probe,
215	.remove = qcom_mhi_qrtr_remove,
216	.dl_xfer_cb = qcom_mhi_qrtr_dl_callback,
217	.ul_xfer_cb = qcom_mhi_qrtr_ul_callback,
218	.id_table = qcom_mhi_qrtr_id_table,
219	.driver = {
220		.name = "qcom_mhi_qrtr",
221		.pm = &qcom_mhi_qrtr_pm_ops,
222	},
223};
224
225module_mhi_driver(qcom_mhi_qrtr_driver);
226
227MODULE_AUTHOR("Chris Lew <clew@codeaurora.org>");
228MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
229MODULE_DESCRIPTION("Qualcomm IPC-Router MHI interface driver");
230MODULE_LICENSE("GPL v2");