[char-misc-next 21/27] mei: fill file pointer in read cb for fixed address client

[Tomas Winkler]

From: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>

The read callback created from a flow control request for
a fixed address client have NULL in the file pointer.
Fill the file pointer using a data from a write callback.

This allows us to drop workaround introduced in:
commit eeabfcf5a92a ("mei: connection to fixed address clients from user-space")

Signed-off-by: Alexander Usyskin <alexander.usyskin@xxxxxxxxx>
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
---
 drivers/misc/mei/client.c |  11 +-
 drivers/misc/mei/main.c   |   5 -
 drivers/misc/mei/wd.c     | 391 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 397 insertions(+), 10 deletions(-)
 create mode 100644 drivers/misc/mei/wd.c

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 3a9c656f1425..a27ae2deecb4 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -1173,11 +1173,12 @@ err:
 /**
  * mei_cl_flow_ctrl_creds - checks flow_control credits for cl.
  *
- * @cl: private data of the file object
+ * @cl: host client
+ * @fp: the file pointer associated with the pointer
  *
  * Return: 1 if mei_flow_ctrl_creds >0, 0 - otherwise.
  */
-static int mei_cl_flow_ctrl_creds(struct mei_cl *cl)
+static int mei_cl_flow_ctrl_creds(struct mei_cl *cl, const struct file *fp)
 {
 	int rets;
 
@@ -1188,7 +1189,7 @@ static int mei_cl_flow_ctrl_creds(struct mei_cl *cl)
 		return 1;
 
 	if (mei_cl_is_fixed_address(cl)) {
-		rets = mei_cl_read_start(cl, mei_cl_mtu(cl), NULL);
+		rets = mei_cl_read_start(cl, mei_cl_mtu(cl), fp);
 		if (rets && rets != -EBUSY)
 			return rets;
 		return 1;
@@ -1568,7 +1569,7 @@ int mei_cl_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
 
 	first_chunk = cb->buf_idx == 0;
 
-	rets = first_chunk ? mei_cl_flow_ctrl_creds(cl) : 1;
+	rets = first_chunk ? mei_cl_flow_ctrl_creds(cl, cb->fp) : 1;
 	if (rets < 0)
 		return rets;
 
@@ -1674,7 +1675,7 @@ int mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb, bool blocking)
 	mei_hdr.msg_complete = 0;
 	mei_hdr.internal = cb->internal;
 
-	rets = mei_cl_flow_ctrl_creds(cl);
+	rets = mei_cl_flow_ctrl_creds(cl, cb->fp);
 	if (rets < 0)
 		goto err;
 
diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index ba9790ead256..c8a8d4df84e4 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -209,11 +209,6 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
 
 	cb = mei_cl_read_cb(cl, file);
 	if (!cb) {
-		if (mei_cl_is_fixed_address(cl) && dev->allow_fixed_address) {
-			cb = mei_cl_read_cb(cl, NULL);
-			if (cb)
-				goto copy_buffer;
-		}
 		rets = 0;
 		goto out;
 	}
diff --git a/drivers/misc/mei/wd.c b/drivers/misc/mei/wd.c
new file mode 100644
index 000000000000..7d9b4ee42f65
--- /dev/null
+++ b/drivers/misc/mei/wd.c
@@ -0,0 +1,391 @@
+/*
+ *
+ * Intel Management Engine Interface (Intel MEI) Linux driver
+ * Copyright (c) 2003-2012, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/device.h>
+#include <linux/sched.h>
+#include <linux/watchdog.h>
+
+#include <linux/mei.h>
+
+#include "mei_dev.h"
+#include "hbm.h"
+#include "client.h"
+
+static const u8 mei_start_wd_params[] = { 0x02, 0x12, 0x13, 0x10 };
+static const u8 mei_stop_wd_params[] = { 0x02, 0x02, 0x14, 0x10 };
+
+/*
+ * AMT Watchdog Device
+ */
+#define INTEL_AMT_WATCHDOG_ID "INTCAMT"
+
+/* UUIDs for AMT F/W clients */
+const uuid_le mei_wd_guid = UUID_LE(0x05B79A6F, 0x4628, 0x4D7F, 0x89,
+						0x9D, 0xA9, 0x15, 0x14, 0xCB,
+						0x32, 0xAB);
+
+static void mei_wd_set_start_timeout(struct mei_device *dev, u16 timeout)
+{
+	dev_dbg(dev->dev, "wd: set timeout=%d.\n", timeout);
+	memcpy(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE);
+	memcpy(dev->wd_data + MEI_WD_HDR_SIZE, &timeout, sizeof(u16));
+}
+
+/**
+ * mei_wd_host_init - connect to the watchdog client
+ *
+ * @dev: the device structure
+ * @me_cl: me client
+ *
+ * Return: -ENOTTY if wd client cannot be found
+ *         -EIO if write has failed
+ *         0 on success
+ */
+int mei_wd_host_init(struct mei_device *dev, struct mei_me_client *me_cl)
+{
+	struct mei_cl *cl = &dev->wd_cl;
+	int ret;
+
+	mei_cl_init(cl, dev);
+
+	dev->wd_timeout = MEI_WD_DEFAULT_TIMEOUT;
+	dev->wd_state = MEI_WD_IDLE;
+
+	ret = mei_cl_link(cl, MEI_WD_HOST_CLIENT_ID);
+	if (ret < 0) {
+		dev_info(dev->dev, "wd: failed link client\n");
+		return ret;
+	}
+
+	ret = mei_cl_connect(cl, me_cl, NULL);
+	if (ret) {
+		dev_err(dev->dev, "wd: failed to connect = %d\n", ret);
+		mei_cl_unlink(cl);
+		return ret;
+	}
+
+	ret = mei_watchdog_register(dev);
+	if (ret) {
+		mei_cl_disconnect(cl);
+		mei_cl_unlink(cl);
+	}
+	return ret;
+}
+
+/**
+ * mei_wd_send - sends watch dog message to fw.
+ *
+ * @dev: the device structure
+ *
+ * Return: 0 if success,
+ *	-EIO when message send fails
+ *	-EINVAL when invalid message is to be sent
+ *	-ENODEV on flow control failure
+ */
+int mei_wd_send(struct mei_device *dev)
+{
+	struct mei_cl *cl = &dev->wd_cl;
+	struct mei_msg_hdr hdr;
+	int ret;
+
+	hdr.host_addr = cl->host_client_id;
+	hdr.me_addr = mei_cl_me_id(cl);
+	hdr.msg_complete = 1;
+	hdr.reserved = 0;
+	hdr.internal = 0;
+
+	if (!memcmp(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE))
+		hdr.length = MEI_WD_START_MSG_SIZE;
+	else if (!memcmp(dev->wd_data, mei_stop_wd_params, MEI_WD_HDR_SIZE))
+		hdr.length = MEI_WD_STOP_MSG_SIZE;
+	else {
+		dev_err(dev->dev, "wd: invalid message is to be sent, aborting\n");
+		return -EINVAL;
+	}
+
+	ret = mei_write_message(dev, &hdr, dev->wd_data);
+	if (ret) {
+		dev_err(dev->dev, "wd: write message failed\n");
+		return ret;
+	}
+
+	ret = mei_cl_flow_ctrl_reduce(cl);
+	if (ret) {
+		dev_err(dev->dev, "wd: flow_ctrl_reduce failed.\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/**
+ * mei_wd_stop - sends watchdog stop message to fw.
+ *
+ * @dev: the device structure
+ *
+ * Return: 0 if success
+ * on error:
+ *	-EIO    when message send fails
+ *	-EINVAL when invalid message is to be sent
+ *	-ETIME  on message timeout
+ */
+int mei_wd_stop(struct mei_device *dev)
+{
+	struct mei_cl *cl = &dev->wd_cl;
+	int ret;
+
+	if (!mei_cl_is_connected(cl) ||
+	    dev->wd_state != MEI_WD_RUNNING)
+		return 0;
+
+	memcpy(dev->wd_data, mei_stop_wd_params, MEI_WD_STOP_MSG_SIZE);
+
+	dev->wd_state = MEI_WD_STOPPING;
+
+	ret = mei_cl_flow_ctrl_creds(cl, NULL);
+	if (ret < 0)
+		goto err;
+
+	if (ret && mei_hbuf_acquire(dev)) {
+		ret = mei_wd_send(dev);
+		if (ret)
+			goto err;
+		dev->wd_pending = false;
+	} else {
+		dev->wd_pending = true;
+	}
+
+	mutex_unlock(&dev->device_lock);
+
+	ret = wait_event_timeout(dev->wait_stop_wd,
+				dev->wd_state == MEI_WD_IDLE,
+				msecs_to_jiffies(MEI_WD_STOP_TIMEOUT));
+	mutex_lock(&dev->device_lock);
+	if (dev->wd_state != MEI_WD_IDLE) {
+		/* timeout */
+		ret = -ETIME;
+		dev_warn(dev->dev, "wd: stop failed to complete ret=%d\n", ret);
+		goto err;
+	}
+	dev_dbg(dev->dev, "wd: stop completed after %u msec\n",
+			MEI_WD_STOP_TIMEOUT - jiffies_to_msecs(ret));
+	return 0;
+err:
+	return ret;
+}
+
+/**
+ * mei_wd_ops_start - wd start command from the watchdog core.
+ *
+ * @wd_dev: watchdog device struct
+ *
+ * Return: 0 if success, negative errno code for failure
+ */
+static int mei_wd_ops_start(struct watchdog_device *wd_dev)
+{
+	struct mei_device *dev;
+	struct mei_cl *cl;
+	int err = -ENODEV;
+
+	dev = watchdog_get_drvdata(wd_dev);
+	if (!dev)
+		return -ENODEV;
+
+	cl = &dev->wd_cl;
+
+	mutex_lock(&dev->device_lock);
+
+	if (dev->dev_state != MEI_DEV_ENABLED) {
+		dev_dbg(dev->dev, "wd: dev_state != MEI_DEV_ENABLED  dev_state = %s\n",
+			mei_dev_state_str(dev->dev_state));
+		goto end_unlock;
+	}
+
+	if (!mei_cl_is_connected(cl)) {
+		cl_dbg(dev, cl, "MEI Driver is not connected to Watchdog Client\n");
+		goto end_unlock;
+	}
+
+	mei_wd_set_start_timeout(dev, dev->wd_timeout);
+
+	err = 0;
+end_unlock:
+	mutex_unlock(&dev->device_lock);
+	return err;
+}
+
+/**
+ * mei_wd_ops_stop -  wd stop command from the watchdog core.
+ *
+ * @wd_dev: watchdog device struct
+ *
+ * Return: 0 if success, negative errno code for failure
+ */
+static int mei_wd_ops_stop(struct watchdog_device *wd_dev)
+{
+	struct mei_device *dev;
+
+	dev = watchdog_get_drvdata(wd_dev);
+	if (!dev)
+		return -ENODEV;
+
+	mutex_lock(&dev->device_lock);
+	mei_wd_stop(dev);
+	mutex_unlock(&dev->device_lock);
+
+	return 0;
+}
+
+/**
+ * mei_wd_ops_ping - wd ping command from the watchdog core.
+ *
+ * @wd_dev: watchdog device struct
+ *
+ * Return: 0 if success, negative errno code for failure
+ */
+static int mei_wd_ops_ping(struct watchdog_device *wd_dev)
+{
+	struct mei_device *dev;
+	struct mei_cl *cl;
+	int ret;
+
+	dev = watchdog_get_drvdata(wd_dev);
+	if (!dev)
+		return -ENODEV;
+
+	cl = &dev->wd_cl;
+
+	mutex_lock(&dev->device_lock);
+
+	if (!mei_cl_is_connected(cl)) {
+		cl_err(dev, cl, "wd: not connected.\n");
+		ret = -ENODEV;
+		goto end;
+	}
+
+	dev->wd_state = MEI_WD_RUNNING;
+
+	ret = mei_cl_flow_ctrl_creds(cl, NULL);
+	if (ret < 0)
+		goto end;
+
+	/* Check if we can send the ping to HW*/
+	if (ret && mei_hbuf_acquire(dev)) {
+		dev_dbg(dev->dev, "wd: sending ping\n");
+
+		ret = mei_wd_send(dev);
+		if (ret)
+			goto end;
+		dev->wd_pending = false;
+	} else {
+		dev->wd_pending = true;
+	}
+
+end:
+	mutex_unlock(&dev->device_lock);
+	return ret;
+}
+
+/**
+ * mei_wd_ops_set_timeout - wd set timeout command from the watchdog core.
+ *
+ * @wd_dev: watchdog device struct
+ * @timeout: timeout value to set
+ *
+ * Return: 0 if success, negative errno code for failure
+ */
+static int mei_wd_ops_set_timeout(struct watchdog_device *wd_dev,
+		unsigned int timeout)
+{
+	struct mei_device *dev;
+
+	dev = watchdog_get_drvdata(wd_dev);
+	if (!dev)
+		return -ENODEV;
+
+	/* Check Timeout value */
+	if (timeout < MEI_WD_MIN_TIMEOUT || timeout > MEI_WD_MAX_TIMEOUT)
+		return -EINVAL;
+
+	mutex_lock(&dev->device_lock);
+
+	dev->wd_timeout = timeout;
+	wd_dev->timeout = timeout;
+	mei_wd_set_start_timeout(dev, dev->wd_timeout);
+
+	mutex_unlock(&dev->device_lock);
+
+	return 0;
+}
+
+/*
+ * Watchdog Device structs
+ */
+static const struct watchdog_ops wd_ops = {
+		.owner = THIS_MODULE,
+		.start = mei_wd_ops_start,
+		.stop = mei_wd_ops_stop,
+		.ping = mei_wd_ops_ping,
+		.set_timeout = mei_wd_ops_set_timeout,
+};
+static const struct watchdog_info wd_info = {
+		.identity = INTEL_AMT_WATCHDOG_ID,
+		.options = WDIOF_KEEPALIVEPING |
+			   WDIOF_SETTIMEOUT |
+			   WDIOF_ALARMONLY,
+};
+
+static struct watchdog_device amt_wd_dev = {
+		.info = &wd_info,
+		.ops = &wd_ops,
+		.timeout = MEI_WD_DEFAULT_TIMEOUT,
+		.min_timeout = MEI_WD_MIN_TIMEOUT,
+		.max_timeout = MEI_WD_MAX_TIMEOUT,
+};
+
+
+int mei_watchdog_register(struct mei_device *dev)
+{
+
+	int ret;
+
+	amt_wd_dev.parent = dev->dev;
+	/* unlock to perserve correct locking order */
+	mutex_unlock(&dev->device_lock);
+	ret = watchdog_register_device(&amt_wd_dev);
+	mutex_lock(&dev->device_lock);
+	if (ret) {
+		dev_err(dev->dev, "wd: unable to register watchdog device = %d.\n",
+			ret);
+		return ret;
+	}
+
+	dev_dbg(dev->dev, "wd: successfully register watchdog interface.\n");
+	watchdog_set_drvdata(&amt_wd_dev, dev);
+	return 0;
+}
+
+void mei_watchdog_unregister(struct mei_device *dev)
+{
+	if (watchdog_get_drvdata(&amt_wd_dev) == NULL)
+		return;
+
+	watchdog_set_drvdata(&amt_wd_dev, NULL);
+	watchdog_unregister_device(&amt_wd_dev);
+}
+
-- 
2.4.3