[char-misc-next 03/11 V2] mei: bus: Initial implementation for I/O routines

[Tomas Winkler]

From: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx>

Signed-off-by: Samuel Ortiz <sameo@xxxxxxxxxxxxxxx>
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
---
 drivers/misc/mei/bus.c     |  226 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/misc/mei/bus.h     |    3 +
 drivers/misc/mei/mei_dev.h |   15 +++
 include/linux/mei_bus.h    |   11 ++
 4 files changed, 255 insertions(+), 0 deletions(-)

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index 0a5e624..97e1988 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -16,6 +16,7 @@
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
+#include <linux/sched.h>
 #include <linux/init.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
@@ -25,6 +26,8 @@
 #include <linux/mei_bus.h>
 
 #include "mei_dev.h"
+#include "hw-me.h"
+#include "client.h"
 #include "bus.h"
 
 static int mei_device_match(struct device *dev, struct device_driver *drv)
@@ -73,6 +76,11 @@ static int mei_device_remove(struct device *dev)
 	if (!client || !dev->driver)
 		return 0;
 
+	if (client->event_cb) {
+		client->event_cb = NULL;
+		cancel_work_sync(&client->event_work);
+	}
+
 	driver = to_mei_driver(dev->driver);
 	if (!driver->remove) {
 		dev->driver = NULL;
@@ -182,3 +190,221 @@ void mei_driver_unregister(struct mei_bus_driver *driver)
 	pr_debug("mei: driver [%s] unregistered\n", driver->driver.name);
 }
 EXPORT_SYMBOL(mei_driver_unregister);
+
+int mei_send(struct mei_cl *cl, u8 *buf, size_t length)
+{
+	struct mei_device *dev;
+	struct mei_msg_hdr mei_hdr;
+	struct mei_cl_cb *cb;
+	int me_cl_id, err;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -ENODEV;
+
+	if (cl->state != MEI_FILE_CONNECTED)
+		return -ENODEV;
+
+	cb = mei_io_cb_init(cl, NULL);
+	if (!cb)
+		return -ENOMEM;
+
+	err = mei_io_cb_alloc_req_buf(cb, length);
+	if (err < 0) {
+		mei_io_cb_free(cb);
+		return err;
+	}
+
+	memcpy(cb->request_buffer.data, buf, length);
+	cb->fop_type = MEI_FOP_WRITE;
+
+	dev = cl->dev;
+
+	mutex_lock(&dev->device_lock);
+
+	/* Check if we have an ME client device */
+	me_cl_id = mei_me_cl_by_id(dev, cl->me_client_id);
+	if (me_cl_id == dev->me_clients_num) {
+		err = -ENODEV;
+		goto out_err;
+	}
+
+	if (length > dev->me_clients[me_cl_id].props.max_msg_length) {
+		err = -EINVAL;
+		goto out_err;
+	}
+
+	err = mei_cl_flow_ctrl_creds(cl);
+	if (err < 0)
+		goto out_err;
+
+	/* Host buffer is not ready, we queue the request */
+	if (err == 0 || !dev->hbuf_is_ready) {
+		cb->buf_idx = 0;
+		mei_hdr.msg_complete = 0;
+		cl->writing_state = MEI_WRITING;
+		list_add_tail(&cb->list, &dev->write_list.list);
+
+		mutex_unlock(&dev->device_lock);
+
+		return length;
+	}
+
+	dev->hbuf_is_ready = false;
+
+	/* Check for a maximum length */
+	if (length > mei_hbuf_max_len(dev)) {
+		mei_hdr.length = mei_hbuf_max_len(dev);
+		mei_hdr.msg_complete = 0;
+	} else {
+		mei_hdr.length = length;
+		mei_hdr.msg_complete = 1;
+	}
+
+	mei_hdr.host_addr = cl->host_client_id;
+	mei_hdr.me_addr = cl->me_client_id;
+	mei_hdr.reserved = 0;
+
+	if (mei_write_message(dev, &mei_hdr, buf)) {
+		err = -EIO;
+		goto out_err;
+	}
+
+	cl->writing_state = MEI_WRITING;
+	cb->buf_idx = mei_hdr.length;
+
+	if (!mei_hdr.msg_complete) {
+		list_add_tail(&cb->list, &dev->write_list.list);
+	} else {
+		if (mei_cl_flow_ctrl_reduce(cl)) {
+			err = -EIO;
+			goto out_err;
+		}
+
+		list_add_tail(&cb->list, &dev->write_waiting_list.list);
+	}
+
+	mutex_unlock(&dev->device_lock);
+
+	return mei_hdr.length;
+
+out_err:
+	mutex_unlock(&dev->device_lock);
+	mei_io_cb_free(cb);
+
+	return err;
+}
+
+int mei_recv(struct mei_cl *cl, u8 *buf, size_t length)
+{
+	struct mei_device *dev;
+	struct mei_cl_cb *cb;
+	size_t r_length;
+	int err;
+
+	if (WARN_ON(!cl || !cl->dev))
+		return -ENODEV;
+
+	dev = cl->dev;
+
+	mutex_lock(&dev->device_lock);
+
+	if (!cl->read_cb) {
+		err = mei_cl_read_start(cl);
+		if (err < 0) {
+			mutex_unlock(&dev->device_lock);
+			return err;
+		}
+	}
+
+	if (cl->reading_state != MEI_READ_COMPLETE &&
+	    !waitqueue_active(&cl->rx_wait)) {
+		mutex_unlock(&dev->device_lock);
+
+		if (wait_event_interruptible(cl->rx_wait,
+				(MEI_READ_COMPLETE == cl->reading_state))) {
+			if (signal_pending(current))
+				return -EINTR;
+			return -ERESTARTSYS;
+		}
+
+		mutex_lock(&dev->device_lock);
+	}
+
+	cb = cl->read_cb;
+
+	if (cl->reading_state != MEI_READ_COMPLETE) {
+		r_length = 0;
+		goto out;
+	}
+
+	r_length = min_t(size_t, length, cb->buf_idx);
+
+	memcpy(buf, cb->response_buffer.data, r_length);
+
+	mei_io_cb_free(cb);
+	cl->reading_state = MEI_IDLE;
+	cl->read_cb = NULL;
+
+out:
+	mutex_unlock(&dev->device_lock);
+
+	return r_length;
+}
+
+int mei_bus_send(struct mei_bus_client *client, u8 *buf, size_t length)
+{
+	struct mei_cl *cl = NULL;
+
+	/* TODO: hook between mei_bus_client and mei_cl */
+
+	if (client->send)
+		return client->send(client, buf, length);
+
+	return mei_send(cl, buf, length);
+}
+EXPORT_SYMBOL(mei_bus_send);
+
+int mei_bus_recv(struct mei_bus_client *client, u8 *buf, size_t length)
+{
+	struct mei_cl *cl = NULL;
+
+	/* TODO: hook between mei_bus_client and mei_cl */
+
+	if (client->recv)
+		return client->recv(client, buf, length);
+
+	return mei_recv(cl, buf, length);
+}
+EXPORT_SYMBOL(mei_bus_recv);
+
+static void mei_bus_event_work(struct work_struct *work)
+{
+	struct mei_bus_client *client;
+
+	client = container_of(work, struct mei_bus_client, event_work);
+
+	if (client->event_cb)
+		client->event_cb(client, client->events, client->event_context);
+
+	client->events = 0;
+
+	/* Prepare for the next read */
+	mei_cl_read_start(client->cl);
+}
+
+int mei_bus_register_event_cb(struct mei_bus_client *client,
+			      mei_bus_event_cb_t event_cb, void *context)
+{
+	if (client->event_cb)
+		return -EALREADY;
+
+	client->events = 0;
+	client->event_cb = event_cb;
+	client->event_context = context;
+	INIT_WORK(&client->event_work, mei_bus_event_work);
+
+	mei_cl_read_start(client->cl);
+
+	return 0;
+}
+EXPORT_SYMBOL(mei_bus_register_event_cb);
diff --git a/drivers/misc/mei/bus.h b/drivers/misc/mei/bus.h
index 7130b67..81789f6 100644
--- a/drivers/misc/mei/bus.h
+++ b/drivers/misc/mei/bus.h
@@ -24,4 +24,7 @@ struct mei_bus_client *mei_add_device(struct mei_device *mei_dev,
 					uuid_le uuid, char *name);
 void mei_remove_device(struct mei_bus_client *client);
 
+int mei_send(struct mei_cl *cl, u8 *buf, size_t length);
+int mei_recv(struct mei_cl *cl, u8 *buf, size_t length);
+
 #endif /* _MEI_BUS_H_ */
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index ce19b26..e95d6e1 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -273,6 +273,13 @@ struct mei_hw_ops {
  * @cl: mei client
  * @driver: mei bus driver for this client
  * @dev: linux driver model device pointer
+ * @send: Tx hook for the bus client. This allows clients to trap
+ *	the driver buffers before actually pushing it to the ME.
+ * @recv: Rx hook for the bus client. This allows clients to trap the
+ *	ME buffers before forwarding them to the driver.
+ * @event_cb: Drivers register this callback to get asynchronous ME
+	events (e.g. Rx buffer pending) notifications.
+ * @events: Events bitmask sent to the driver.
  * @priv_data: client private data
  */
 struct mei_bus_client {
@@ -284,6 +291,14 @@ struct mei_bus_client {
 	struct mei_bus_driver *driver;
 	struct device dev;
 
+	int (*send)(struct mei_bus_client *client, u8 *buf, size_t length);
+	int (*recv)(struct mei_bus_client *client, u8 *buf, size_t length);
+
+	struct work_struct event_work;
+	mei_bus_event_cb_t event_cb;
+	void *event_context;
+	unsigned long events;
+
 	void *priv_data;
 };
 
diff --git a/include/linux/mei_bus.h b/include/linux/mei_bus.h
index 0bd1189c..738e073 100644
--- a/include/linux/mei_bus.h
+++ b/include/linux/mei_bus.h
@@ -88,7 +88,18 @@ struct mei_bus_driver {
 	int (*remove)(struct mei_bus_client *client);
 };
 
+#define MEI_BUS_EVENT_RX 0
+#define MEI_BUS_EVENT_TX 1
+
 int mei_driver_register(struct mei_bus_driver *driver);
 void mei_driver_unregister(struct mei_bus_driver *driver);
 
+int mei_bus_send(struct mei_bus_client *client, u8 *buf, size_t length);
+int mei_bus_recv(struct mei_bus_client *client, u8 *buf, size_t length);
+
+typedef void (*mei_bus_event_cb_t)(struct mei_bus_client *client,
+				   u32 events, void *context);
+int mei_bus_register_event_cb(struct mei_bus_client *client,
+			      mei_bus_event_cb_t read_cb, void *context);
+
 #endif /* _LINUX_MEI_BUS_H */
-- 
1.7.4.4

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