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Commit fa04d094 authored by Satyajit Desai's avatar Satyajit Desai
Browse files

soc: qcom: Add support for QDSS bridge driver 



Add support to route QDSS data received from MDM via MHI
to USB. The driver will help route diag traffic over the
QDSS sub-system to USB on APPS side. It acts as a bridge
between PCIE MHI and USB interface.

Change-Id: Ifa50d4c3ce39e10e928e3e6f3e79085d2bc9d4e6
Signed-off-by: default avatarSatyajit Desai <sadesai@codeaurora.org>
parent cc8c86a2

Documentation/devicetree/bindings/arm/msm/qdss_mhi.txt

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Qualcomm Technologies, Inc. QDSS bridge Driver



This device will enable routing debug data from modem

subsystem to APSS host.



Required properties:

-compatible : "qcom,qdss-mhi".

-qcom,mhi : phandle of MHI Device to connect to.



Example:

	qcom,qdss-mhi {

		compatible = "qcom,qdss-mhi";

		qcom,mhi = <&mhi_0>;

	};

drivers/soc/qcom/Kconfig

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@@ -686,3 +686,11 @@ config MSM_JTAGV8 
	  and ETM registers are saved and restored across power collapse.

	  If unsure, say 'N' here to avoid potential power, performance and

	  memory penalty.



config QCOM_QDSS_BRIDGE

	bool "Configure bridge driver for QTI/Qualcomm Technologies, Inc. MDM"

	depends on MSM_MHI

	help

	  The driver will help route diag traffic from modem side over the QDSS

	  sub-system to USB on APSS side. The driver acts as a bridge between the

	  MHI and USB interface. If unsure, say N.
 
 No newline at end of file

drivers/soc/qcom/Makefile

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@@ -79,3 +79,4 @@ obj-$(CONFIG_QCOM_SMCINVOKE) += smcinvoke.o 
obj-$(CONFIG_QMP_DEBUGFS_CLIENT) += qmp-debugfs-client.o

obj-$(CONFIG_MSM_REMOTEQDSS) += remoteqdss.o

obj-$(CONFIG_QSEE_IPC_IRQ_BRIDGE) += qsee_ipc_irq_bridge.o

obj-$(CONFIG_QCOM_QDSS_BRIDGE) += qdss_bridge.o
 
 No newline at end of file

drivers/soc/qcom/qdss_bridge.c

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/* Copyright (c) 2017, The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#define KMSG_COMPONENT "QDSS diag bridge"

#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt



#include <linux/slab.h>

#include <linux/module.h>

#include <linux/ratelimit.h>

#include <linux/workqueue.h>

#include <linux/platform_device.h>

#include <linux/moduleparam.h>

#include <linux/msm_mhi.h>

#include <linux/usb/usb_qdss.h>

#include "qdss_bridge.h"



#define MODULE_NAME "qdss_bridge"



#define QDSS_BUF_SIZE		(16*1024)

#define MHI_CLIENT_QDSS_IN	9



/* Max number of objects needed */

static int poolsize = 32;

module_param(poolsize, int, 0644);



/* Size of single buffer */

static int itemsize = QDSS_BUF_SIZE;

module_param(itemsize, int, 0644);



static int qdss_destroy_buf_tbl(struct qdss_bridge_drvdata *drvdata)

{

	struct list_head *start, *temp;

	struct qdss_buf_tbl_lst *entry = NULL;



	list_for_each_safe(start, temp, &drvdata->buf_tbl) {

		entry = list_entry(start, struct qdss_buf_tbl_lst, link);

		list_del(&entry->link);

		kfree(entry->buf);

		kfree(entry->usb_req);

		kfree(entry);

	}



	return 0;

}



static int qdss_create_buf_tbl(struct qdss_bridge_drvdata *drvdata)

{

	struct qdss_buf_tbl_lst *entry;

	void *buf;

	struct qdss_request *usb_req;

	int i;



	for (i = 0; i < poolsize; i++) {

		entry = kzalloc(sizeof(*entry), GFP_KERNEL);

		if (!entry)

			goto err;



		buf = kzalloc(QDSS_BUF_SIZE, GFP_KERNEL);

		usb_req = kzalloc(sizeof(*usb_req), GFP_KERNEL);



		entry->buf = buf;

		entry->usb_req = usb_req;

		atomic_set(&entry->available, 1);

		list_add_tail(&entry->link, &drvdata->buf_tbl);



		if (!buf || !usb_req)

			goto err;

	}



	return 0;

err:

	qdss_destroy_buf_tbl(drvdata);

	return -ENOMEM;

}



struct qdss_buf_tbl_lst *qdss_get_buf_tbl_entry(

					struct qdss_bridge_drvdata *drvdata,

					void *buf)

{

	struct qdss_buf_tbl_lst *entry;



	list_for_each_entry(entry, &drvdata->buf_tbl, link) {

		if (atomic_read(&entry->available))

			continue;

		if (entry->buf == buf)

			return entry;

	}



	return NULL;

}



struct qdss_buf_tbl_lst *qdss_get_entry(struct qdss_bridge_drvdata *drvdata)

{

	struct qdss_buf_tbl_lst *item;



	list_for_each_entry(item, &drvdata->buf_tbl, link)

		if (atomic_cmpxchg(&item->available, 1, 0) == 1)

			return item;



	return NULL;

}



static void qdss_buf_tbl_remove(struct qdss_bridge_drvdata *drvdata,

				void *buf)

{

	struct qdss_buf_tbl_lst *entry = NULL;



	list_for_each_entry(entry, &drvdata->buf_tbl, link) {

		if (entry->buf != buf)

			continue;

		atomic_set(&entry->available, 1);

		return;

	}



	pr_err_ratelimited("Failed to find buffer for removal\n");

}



static void mhi_ch_close(struct qdss_bridge_drvdata *drvdata)

{

	flush_workqueue(drvdata->mhi_wq);

	qdss_destroy_buf_tbl(drvdata);

	mhi_close_channel(drvdata->hdl);

}



static void mhi_close_work_fn(struct work_struct *work)

{

	struct qdss_bridge_drvdata *drvdata =

				container_of(work,

					     struct qdss_bridge_drvdata,

					     close_work);



	usb_qdss_close(drvdata->usb_ch);

	mhi_ch_close(drvdata);

}



static void mhi_read_work_fn(struct work_struct *work)

{

	int err = 0;

	enum MHI_FLAGS mhi_flags = MHI_EOT;

	struct qdss_buf_tbl_lst *entry;



	struct qdss_bridge_drvdata *drvdata =

				container_of(work,

					     struct qdss_bridge_drvdata,

					     read_work);



	do {

		if (!drvdata->opened)

			break;

		entry = qdss_get_entry(drvdata);

		if (!entry)

			break;



		err = mhi_queue_xfer(drvdata->hdl, entry->buf, QDSS_BUF_SIZE,

				      mhi_flags);

		if (err) {

			pr_err_ratelimited("Unable to read from MHI buffer err:%d",

					   err);

			goto fail;

		}

	} while (entry);



	return;

fail:

	qdss_buf_tbl_remove(drvdata, entry->buf);

	queue_work(drvdata->mhi_wq, &drvdata->read_work);

}



static int mhi_queue_read(struct qdss_bridge_drvdata *drvdata)

{

	queue_work(drvdata->mhi_wq, &(drvdata->read_work));

	return 0;

}



static int usb_write(struct qdss_bridge_drvdata *drvdata,

			     struct mhi_result *result)

{

	int ret = 0;

	struct qdss_buf_tbl_lst *entry;



	entry = qdss_get_buf_tbl_entry(drvdata, result->buf_addr);

	if (!entry)

		return -EINVAL;



	entry->usb_req->buf = result->buf_addr;

	entry->usb_req->length = result->bytes_xferd;

	ret = usb_qdss_data_write(drvdata->usb_ch, entry->usb_req);



	return ret;

}



static void mhi_read_done_work_fn(struct work_struct *work)

{

	unsigned char *buf = NULL;

	struct mhi_result result;

	int err = 0;

	struct qdss_bridge_drvdata *drvdata =

				container_of(work,

					     struct qdss_bridge_drvdata,

					     read_done_work);



	do {

		err = mhi_poll_inbound(drvdata->hdl, &result);

		if (err) {

			pr_debug("MHI poll failed err:%d\n", err);

			break;

		}

		buf = result.buf_addr;

		if (!buf)

			break;

		err = usb_write(drvdata, &result);

		if (err)

			qdss_buf_tbl_remove(drvdata, buf);

	} while (1);

}



static void usb_write_done(struct qdss_bridge_drvdata *drvdata,

				   struct qdss_request *d_req)

{

	if (d_req->status) {

		pr_err_ratelimited("USB write failed err:%d\n", d_req->status);

		mhi_queue_read(drvdata);

		return;

	}

	qdss_buf_tbl_remove(drvdata, d_req->buf);

	mhi_queue_read(drvdata);

}



static void usb_notifier(void *priv, unsigned int event,

			struct qdss_request *d_req, struct usb_qdss_ch *ch)

{

	struct qdss_bridge_drvdata *drvdata = priv;



	if (!drvdata)

		return;



	switch (event) {

	case USB_QDSS_CONNECT:

		usb_qdss_alloc_req(drvdata->usb_ch, poolsize, 0);

		mhi_queue_read(drvdata);

		break;



	case USB_QDSS_DISCONNECT:

		/* Leave MHI/USB open.Only close on MHI disconnect */

		break;



	case USB_QDSS_DATA_WRITE_DONE:

		usb_write_done(drvdata, d_req);

		break;



	default:

		break;

	}

}



static int mhi_ch_open(struct qdss_bridge_drvdata *drvdata)

{

	int ret;



	if (drvdata->opened)

		return 0;



	ret = mhi_open_channel(drvdata->hdl);

	if (ret) {

		pr_err("Unable to open MHI channel\n");

		return ret;

	}



	ret = mhi_get_free_desc(drvdata->hdl);

	if (ret <= 0)

		return -EIO;



	drvdata->opened = 1;

	return 0;

}



static void qdss_bridge_open_work_fn(struct work_struct *work)

{

	struct qdss_bridge_drvdata *drvdata =

				container_of(work,

					     struct qdss_bridge_drvdata,

					     open_work);

	int ret;



	ret = mhi_ch_open(drvdata);

	if (ret)

		goto err_open;



	ret = qdss_create_buf_tbl(drvdata);

	if (ret)

		goto err;



	drvdata->usb_ch = usb_qdss_open("qdss_mdm", drvdata, usb_notifier);

	if (IS_ERR_OR_NULL(drvdata->usb_ch)) {

		ret = PTR_ERR(drvdata->usb_ch);

		goto err;

	}



	return;

err:

	mhi_ch_close(drvdata);

err_open:

	pr_err("Open work failed with err:%d\n", ret);

}



static void mhi_notifier(struct mhi_cb_info *cb_info)

{

	struct mhi_result *result;

	struct qdss_bridge_drvdata *drvdata;



	if (!cb_info)

		return;



	result = cb_info->result;

	if (!result) {

		pr_err_ratelimited("Failed to obtain MHI result\n");

		return;

	}



	drvdata = (struct qdss_bridge_drvdata *)cb_info->result->user_data;

	if (!drvdata) {

		pr_err_ratelimited("MHI returned invalid drvdata\n");

		return;

	}



	switch (cb_info->cb_reason) {

	case MHI_CB_MHI_ENABLED:

		queue_work(drvdata->mhi_wq, &drvdata->open_work);

		break;



	case MHI_CB_XFER:

		if (!drvdata->opened)

			break;



		queue_work(drvdata->mhi_wq, &drvdata->read_done_work);

		break;



	case MHI_CB_MHI_DISABLED:

		if (!drvdata->opened)

			break;



		drvdata->opened = 0;

		queue_work(drvdata->mhi_wq, &drvdata->close_work);

		break;



	default:

		pr_err_ratelimited("MHI returned invalid cb reason 0x%x\n",

		       cb_info->cb_reason);

		break;

	}

}



static int qdss_mhi_register_ch(struct qdss_bridge_drvdata *drvdata)

{

	struct mhi_client_info_t *client_info;

	int ret;

	struct mhi_client_info_t *mhi_info;



	client_info = devm_kzalloc(drvdata->dev, sizeof(*client_info),

				   GFP_KERNEL);

	if (!client_info)

		return -ENOMEM;



	client_info->mhi_client_cb = mhi_notifier;

	drvdata->client_info = client_info;



	mhi_info = client_info;

	mhi_info->chan = MHI_CLIENT_QDSS_IN;

	mhi_info->dev = drvdata->dev;

	mhi_info->node_name = "qcom,mhi";

	mhi_info->user_data = drvdata;



	ret = mhi_register_channel(&drvdata->hdl, mhi_info);

	return ret;

}



int qdss_mhi_init(struct qdss_bridge_drvdata *drvdata)

{

	int ret;



	drvdata->mhi_wq = create_singlethread_workqueue(MODULE_NAME);

	if (!drvdata->mhi_wq)

		return -ENOMEM;



	INIT_WORK(&(drvdata->read_work), mhi_read_work_fn);

	INIT_WORK(&(drvdata->read_done_work), mhi_read_done_work_fn);

	INIT_WORK(&(drvdata->open_work), qdss_bridge_open_work_fn);

	INIT_WORK(&(drvdata->close_work), mhi_close_work_fn);

	INIT_LIST_HEAD(&drvdata->buf_tbl);

	drvdata->opened = 0;



	ret = qdss_mhi_register_ch(drvdata);

	if (ret) {

		destroy_workqueue(drvdata->mhi_wq);

		pr_err("Unable to register MHI read channel err:%d\n", ret);

		return ret;

	}



	return 0;

}



static int qdss_mhi_probe(struct platform_device *pdev)

{

	int ret;

	struct device *dev = &pdev->dev;

	struct qdss_bridge_drvdata *drvdata;



	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);

	if (!drvdata) {

		ret = -ENOMEM;

		return ret;

	}



	drvdata->dev = &pdev->dev;

	platform_set_drvdata(pdev, drvdata);



	ret = qdss_mhi_init(drvdata);

	if (ret)

		goto err;



	return 0;

err:

	pr_err("Device probe failed err:%d\n", ret);

	return ret;

}



static const struct of_device_id qdss_mhi_table[] = {

	{.compatible = "qcom,qdss-mhi"},

	{},

};



static struct platform_driver qdss_mhi_driver = {

	.probe = qdss_mhi_probe,

	.driver = {

		.name = MODULE_NAME,

		.owner = THIS_MODULE,

		.of_match_table = qdss_mhi_table,

	},

};



static int __init qdss_bridge_init(void)

{

	return platform_driver_register(&qdss_mhi_driver);

}



static void __exit qdss_bridge_exit(void)

{

	platform_driver_unregister(&qdss_mhi_driver);

}



module_init(qdss_bridge_init);

module_exit(qdss_bridge_exit);

MODULE_LICENSE("GPL v2")

MODULE_DESCRIPTION("QDSS Bridge driver");

drivers/soc/qcom/qdss_bridge.h

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Original line number Diff line number Diff line 
/* Copyright (c) 2017, The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#ifndef _QDSS_BRIDGE_H

#define _QDSS_BRIDGE_H



struct qdss_buf_tbl_lst {

	struct list_head link;

	unsigned char *buf;

	struct qdss_request *usb_req;

	atomic_t available;

};



struct qdss_bridge_drvdata {

	struct device *dev;

	bool opened;

	struct work_struct read_work;

	struct work_struct read_done_work;

	struct work_struct open_work;

	struct work_struct close_work;

	struct workqueue_struct *mhi_wq;

	struct mhi_client_handle *hdl;

	struct mhi_client_info_t *client_info;

	struct list_head buf_tbl;

	struct usb_qdss_ch *usb_ch;

};



#endif