video: tegra: Add control device to dc extension driver

This device exposes control over everything that's not specific to one
of T20's two display controllers.  It supports:
- output devices
- event delivery
- hotplug events

bug 818525

Original-Change-Id: I3a46f1dddc483b08ed3ee91a4f9c64111c1fd7eb
Signed-off-by: Robert Morell <rmorell@nvidia.com>
Reviewed-on: http://git-master/r/40520
Reviewed-by: Varun Colbert <vcolbert@nvidia.com>
Tested-by: Varun Colbert <vcolbert@nvidia.com>

Rebase-Id: R9e49fe41f3327b797ec65c3729f4f94edbb45307

5 files changed, 488 insertions, 7 deletions

diff --git a/drivers/video/tegra/dc/ext/Makefile b/drivers/video/tegra/dc/ext/Makefile
index 1a202f95f391..19860ab5db11 100644
--- a/drivers/video/tegra/dc/ext/Makefile
+++ b/drivers/video/tegra/dc/ext/Makefile
@@ -1,3 +1,5 @@
 obj-y += dev.o
 obj-y += util.o
 obj-y += cursor.o
+obj-y += events.o
+obj-y += control.o
diff --git a/drivers/video/tegra/dc/ext/control.c b/drivers/video/tegra/dc/ext/control.c
new file mode 100644
index 000000000000..6cc2f9a7d54a
--- /dev/null
+++ b/drivers/video/tegra/dc/ext/control.c
@@ -0,0 +1,220 @@
+/*
+ * drivers/video/tegra/dc/ext/control.c
+ *
+ * Copyright (C) 2011, NVIDIA Corporation
+ *
+ * Author: Robert Morell <rmorell@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+
+#include "tegra_dc_ext_priv.h"
+
+static struct tegra_dc_ext_control g_control;
+
+int tegra_dc_ext_process_hotplug(int output)
+{
+	return tegra_dc_ext_queue_hotplug(&g_control, output);
+}
+
+static int
+get_output_properties(struct tegra_dc_ext_control_output_properties *properties)
+{
+	/* TODO: this should be more dynamic */
+	if (properties->handle > 2)
+		return -EINVAL;
+
+	switch (properties->handle) {
+	case 0:
+		properties->type = TEGRA_DC_EXT_LVDS;
+		properties->connected = 1;
+		break;
+	case 1:
+		properties->type = TEGRA_DC_EXT_HDMI;
+		properties->connected = 1;
+		break;
+	default:
+		return -EINVAL;
+	}
+	properties->associated_head = properties->handle;
+
+	return 0;
+}
+
+static int get_output_edid(struct tegra_dc_ext_control_output_edid *edid)
+{
+	/* XXX implement me */
+	return -ENOTSUPP;
+}
+
+static int set_event_mask(struct tegra_dc_ext_control_user *user, u32 mask)
+{
+	struct list_head *list, *tmp;
+
+	if (mask & ~TEGRA_DC_EXT_EVENT_MASK_ALL)
+		return -EINVAL;
+
+	mutex_lock(&user->lock);
+
+	user->event_mask = mask;
+
+	list_for_each_safe(list, tmp, &user->event_list) {
+		struct tegra_dc_ext_event_list *ev_list;
+		ev_list = list_entry(list, struct tegra_dc_ext_event_list,
+			list);
+		if (!(mask & ev_list->event.type)) {
+			list_del(list);
+			kfree(ev_list);
+		}
+	}
+	mutex_unlock(&user->lock);
+
+	return 0;
+}
+
+static long tegra_dc_ext_control_ioctl(struct file *filp, unsigned int cmd,
+				       unsigned long arg)
+{
+	void __user *user_arg = (void __user *)arg;
+	struct tegra_dc_ext_control_user *user = filp->private_data;
+
+	switch (cmd) {
+	case TEGRA_DC_EXT_CONTROL_GET_NUM_OUTPUTS:
+	{
+		u32 num = tegra_dc_ext_get_num_outputs();
+
+		if (copy_to_user(user_arg, &num, sizeof(num)))
+			return -EFAULT;
+
+		return 0;
+	}
+	case TEGRA_DC_EXT_CONTROL_GET_OUTPUT_PROPERTIES:
+	{
+		struct tegra_dc_ext_control_output_properties args;
+		int ret;
+
+		if (copy_from_user(&args, user_arg, sizeof(args)))
+			return -EFAULT;
+
+		ret = get_output_properties(&args);
+
+		if (copy_to_user(user_arg, &args, sizeof(args)))
+			return -EFAULT;
+
+		return ret;
+	}
+	case TEGRA_DC_EXT_CONTROL_GET_OUTPUT_EDID:
+	{
+		struct tegra_dc_ext_control_output_edid args;
+		int ret;
+
+		if (copy_from_user(&args, user_arg, sizeof(args)))
+			return -EFAULT;
+
+		ret = get_output_edid(&args);
+
+		if (copy_to_user(user_arg, &args, sizeof(args)))
+			return -EFAULT;
+
+		return ret;
+	}
+	case TEGRA_DC_EXT_CONTROL_SET_EVENT_MASK:
+		return set_event_mask(user, (u32) arg);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int tegra_dc_ext_control_open(struct inode *inode, struct file *filp)
+{
+	struct tegra_dc_ext_control_user *user;
+	struct tegra_dc_ext_control *control;
+
+	user = kzalloc(sizeof(*user), GFP_KERNEL);
+	if (!user)
+		return -ENOMEM;
+
+	control = container_of(inode->i_cdev, struct tegra_dc_ext_control,
+		cdev);
+	user->control = control;;
+
+	INIT_LIST_HEAD(&user->event_list);
+	mutex_init(&user->lock);
+
+	filp->private_data = user;
+
+	mutex_lock(&control->lock);
+	list_add(&user->list, &control->users);
+	mutex_unlock(&control->lock);
+
+	return 0;
+}
+
+static int tegra_dc_ext_control_release(struct inode *inode, struct file *filp)
+{
+	struct tegra_dc_ext_control_user *user = filp->private_data;
+	struct tegra_dc_ext_control *control = user->control;
+
+	/* This will free any pending events for this user */
+	set_event_mask(user, 0);
+
+	mutex_lock(&control->lock);
+	list_del(&user->list);
+	mutex_unlock(&control->lock);
+
+	kfree(user);
+
+	return 0;
+}
+
+static const struct file_operations tegra_dc_ext_event_devops = {
+	.owner =		THIS_MODULE,
+	.open =			tegra_dc_ext_control_open,
+	.release =		tegra_dc_ext_control_release,
+	.read =			tegra_dc_ext_event_read,
+	.unlocked_ioctl =	tegra_dc_ext_control_ioctl,
+};
+
+int tegra_dc_ext_control_init(void)
+{
+	struct tegra_dc_ext_control *control = &g_control;
+	int ret;
+
+	cdev_init(&control->cdev, &tegra_dc_ext_event_devops);
+	control->cdev.owner = THIS_MODULE;
+	ret = cdev_add(&control->cdev, tegra_dc_ext_devno, 1);
+	if (ret)
+		return ret;
+
+	control->dev = device_create(tegra_dc_ext_class,
+				     NULL,
+				     tegra_dc_ext_devno,
+				     NULL,
+				     "tegra_dc_ctrl");
+	if (IS_ERR(control->dev)) {
+		ret = PTR_ERR(control->dev);
+		cdev_del(&control->cdev);
+	}
+
+	mutex_init(&control->lock);
+
+	INIT_LIST_HEAD(&control->users);
+
+	return ret;
+}
diff --git a/drivers/video/tegra/dc/ext/dev.c b/drivers/video/tegra/dc/ext/dev.c
index 7e077737f910..05569ea74d0a 100644
--- a/drivers/video/tegra/dc/ext/dev.c
+++ b/drivers/video/tegra/dc/ext/dev.c
@@ -38,8 +38,9 @@
 #include "../../nvmap/nvmap.h"
 #include "tegra_dc_ext_priv.h"
 
-static int tegra_dc_ext_devno;
-static struct class *tegra_dc_ext_class;
+int tegra_dc_ext_devno;
+struct class *tegra_dc_ext_class;
+static int head_count;
 
 struct tegra_dc_ext_flip_win {
 	struct tegra_dc_ext_flip_windowattr	attr;
@@ -55,6 +56,12 @@ struct tegra_dc_ext_flip_data {
 	struct tegra_dc_ext_flip_win	win[DC_N_WINDOWS];
 };
 
+int tegra_dc_ext_get_num_outputs(void)
+{
+	/* TODO: decouple output count from head count */
+	return head_count;
+}
+
 static int tegra_dc_ext_set_nvmap_fd(struct tegra_dc_ext_user *user,
 				     int fd)
 {
@@ -574,15 +581,18 @@ struct tegra_dc_ext *tegra_dc_ext_register(struct nvhost_device *ndev,
 {
 	int ret;
 	struct tegra_dc_ext *ext;
+	int devno;
 
 	ext = kzalloc(sizeof(*ext), GFP_KERNEL);
 	if (!ext)
 		return ERR_PTR(-ENOMEM);
 
 	BUG_ON(!tegra_dc_ext_devno);
+	devno = tegra_dc_ext_devno + head_count + 1;
+
 	cdev_init(&ext->cdev, &tegra_dc_devops);
 	ext->cdev.owner = THIS_MODULE;
-	ret = cdev_add(&ext->cdev, tegra_dc_ext_devno, 1);
+	ret = cdev_add(&ext->cdev, devno, 1);
 	if (ret) {
 		dev_err(&ndev->dev, "Failed to create character device\n");
 		goto cleanup_alloc;
@@ -590,7 +600,7 @@ struct tegra_dc_ext *tegra_dc_ext_register(struct nvhost_device *ndev,
 
 	ext->dev = device_create(tegra_dc_ext_class,
 				 &ndev->dev,
-				 tegra_dc_ext_devno,
+				 devno,
 				 NULL,
 				 "tegra_dc_%d",
 				 ndev->id);
@@ -614,7 +624,7 @@ struct tegra_dc_ext *tegra_dc_ext_register(struct nvhost_device *ndev,
 
 	mutex_init(&ext->cursor.lock);
 
-	tegra_dc_ext_devno++;
+	head_count++;
 
 	return ext;
 
@@ -649,6 +659,8 @@ void tegra_dc_ext_unregister(struct tegra_dc_ext *ext)
 	cdev_del(&ext->cdev);
 
 	kfree(ext);
+
+	head_count--;
 }
 
 int __init tegra_dc_ext_module_init(void)
@@ -661,11 +673,24 @@ int __init tegra_dc_ext_module_init(void)
 		return -ENOMEM;
 	}
 
+	/* Reserve one character device per head, plus the control device */
 	ret = alloc_chrdev_region(&tegra_dc_ext_devno,
-				  0, TEGRA_MAX_DC,
+				  0, TEGRA_MAX_DC + 1,
 				  "tegra_dc_ext");
 	if (ret)
-		class_destroy(tegra_dc_ext_class);
+		goto cleanup_class;
+
+	ret = tegra_dc_ext_control_init();
+	if (ret)
+		goto cleanup_region;
+
+	return 0;
+
+cleanup_region:
+	unregister_chrdev_region(tegra_dc_ext_devno, TEGRA_MAX_DC);
+
+cleanup_class:
+	class_destroy(tegra_dc_ext_class);
 
 	return ret;
 }
diff --git a/drivers/video/tegra/dc/ext/events.c b/drivers/video/tegra/dc/ext/events.c
new file mode 100644
index 000000000000..226571e98fd7
--- /dev/null
+++ b/drivers/video/tegra/dc/ext/events.c
@@ -0,0 +1,183 @@
+/*
+ * drivers/video/tegra/dc/ext/events.c
+ *
+ * Copyright (C) 2011, NVIDIA Corporation
+ *
+ * Author: Robert Morell <rmorell@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.
+ */
+
+#include <linux/err.h>
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+
+#include "tegra_dc_ext_priv.h"
+
+static DECLARE_WAIT_QUEUE_HEAD(event_wait);
+
+static int get_next_event(struct tegra_dc_ext_control_user *user,
+			  struct tegra_dc_ext_event_list *event,
+			  bool block)
+{
+	struct list_head *list = &user->event_list;
+	struct tegra_dc_ext_event_list *next_event;
+	int ret;
+
+	if (block) {
+		ret = wait_event_interruptible(event_wait,
+			atomic_read(&user->num_events));
+
+		if (unlikely(ret)) {
+			if (ret == -ERESTARTSYS)
+				return -EAGAIN;
+			return ret;
+		}
+	} else {
+		if (!atomic_read(&user->num_events))
+			return 0;
+	}
+
+	mutex_lock(&user->lock);
+
+	BUG_ON(list_empty(list));
+	next_event = list_first_entry(list, struct tegra_dc_ext_event_list,
+			list);
+	*event = *next_event;
+	list_del(&next_event->list);
+	kfree(next_event);
+
+	atomic_dec(&user->num_events);
+
+	mutex_unlock(&user->lock);
+
+	return 1;
+}
+
+ssize_t tegra_dc_ext_event_read(struct file *filp, char __user *buf,
+				size_t size, loff_t *ppos)
+{
+	struct tegra_dc_ext_control_user *user = filp->private_data;
+	struct tegra_dc_ext_event_list event_elem;
+	struct tegra_dc_ext_event *event = &event_elem.event;
+	ssize_t retval = 0, to_copy, event_size, pending;
+	loff_t previously_copied = 0;
+	char *to_copy_ptr;
+
+	if (size == 0)
+		return 0;
+
+	if (user->partial_copy) {
+		/*
+		 * We didn't transfer the entire event last time, need to
+		 * finish it up
+		 */
+		event_elem = user->event_to_copy;
+		previously_copied = user->partial_copy;
+	} else {
+		/* Get the next event, if any */
+		pending = get_next_event(user, &event_elem,
+			!(filp->f_flags & O_NONBLOCK));
+		if (pending <= 0)
+			return pending;
+	}
+
+	/* Write the event to the user */
+	event_size = sizeof(*event) + event->data_size;
+	BUG_ON(event_size <= previously_copied);
+	event_size -= previously_copied;
+
+	to_copy_ptr = (char *)event + previously_copied;
+	to_copy = min_t(ssize_t, size, event_size);
+	if (copy_to_user(buf, to_copy_ptr, to_copy)) {
+		retval = -EFAULT;
+		to_copy = 0;
+	}
+
+	/* Note that we currently only deliver one event at a time */
+
+	if (event_size > to_copy) {
+		/*
+		 * We were only able to copy part of this event.  Stash it for
+		 * next time.
+		 */
+		user->event_to_copy = event_elem;
+		user->partial_copy = previously_copied + to_copy;
+	} else {
+		user->partial_copy = 0;
+	}
+
+	return to_copy ? to_copy : retval;
+}
+
+static int tegra_dc_ext_queue_event(struct tegra_dc_ext_control *control,
+				    struct tegra_dc_ext_event *event)
+{
+	struct list_head *cur;
+	int retval = 0;
+
+	mutex_lock(&control->lock);
+	list_for_each(cur, &control->users) {
+		struct tegra_dc_ext_control_user *user;
+		struct tegra_dc_ext_event_list *ev_list;
+
+		user = container_of(cur, struct tegra_dc_ext_control_user,
+			list);
+		mutex_lock(&user->lock);
+
+		if (!(user->event_mask & event->type)) {
+			mutex_unlock(&user->lock);
+			continue;
+		}
+
+		ev_list = kmalloc(sizeof(*ev_list), GFP_KERNEL);
+		if (!ev_list) {
+			retval = -ENOMEM;
+			mutex_unlock(&user->lock);
+			continue;
+		}
+
+		memcpy(&ev_list->event, event,
+			sizeof(*event) + event->data_size);
+
+		list_add_tail(&ev_list->list, &user->event_list);
+
+		atomic_inc(&user->num_events);
+
+		mutex_unlock(&user->lock);
+	}
+	mutex_unlock(&control->lock);
+
+	/* Is it worth it to track waiters with more granularity? */
+	wake_up(&event_wait);
+
+	return retval;
+}
+
+int tegra_dc_ext_queue_hotplug(struct tegra_dc_ext_control *control, int output)
+{
+	struct {
+		struct tegra_dc_ext_event event;
+		struct tegra_dc_ext_control_event_hotplug hotplug;
+	} __packed pack;
+
+	pack.event.type = TEGRA_DC_EXT_EVENT_HOTPLUG;
+	pack.event.data_size = sizeof(pack.hotplug);
+
+	pack.hotplug.handle = output;
+
+	tegra_dc_ext_queue_event(control, &pack.event);
+
+	return 0;
+}
diff --git a/drivers/video/tegra/dc/ext/tegra_dc_ext_priv.h b/drivers/video/tegra/dc/ext/tegra_dc_ext_priv.h
index 251c072683c7..a1cd88325896 100644
--- a/drivers/video/tegra/dc/ext/tegra_dc_ext_priv.h
+++ b/drivers/video/tegra/dc/ext/tegra_dc_ext_priv.h
@@ -20,6 +20,7 @@
 #define __TEGRA_DC_EXT_PRIV_H
 
 #include <linux/cdev.h>
+#include <linux/list.h>
 #include <linux/mutex.h>
 
 #include <mach/dc.h>
@@ -67,6 +68,47 @@ struct tegra_dc_ext {
 	bool				enabled;
 };
 
+#define TEGRA_DC_EXT_EVENT_MASK_ALL \
+	TEGRA_DC_EXT_EVENT_HOTPLUG
+
+#define TEGRA_DC_EXT_EVENT_MAX_SZ	8
+
+struct tegra_dc_ext_event_list {
+	struct tegra_dc_ext_event	event;
+	/* The data field _must_ follow the event field. */
+	char				data[TEGRA_DC_EXT_EVENT_MAX_SZ];
+
+	struct list_head		list;
+};
+
+struct tegra_dc_ext_control_user {
+	struct tegra_dc_ext_control	*control;
+
+	struct list_head		event_list;
+	atomic_t			num_events;
+
+	u32				event_mask;
+
+	struct tegra_dc_ext_event_list	event_to_copy;
+	loff_t				partial_copy;
+
+	struct mutex			lock;
+
+	struct list_head		list;
+};
+
+struct tegra_dc_ext_control {
+	struct cdev			cdev;
+	struct device			*dev;
+
+	struct list_head		users;
+
+	struct mutex			lock;
+};
+
+extern int tegra_dc_ext_devno;
+extern struct class *tegra_dc_ext_class;
+
 extern int tegra_dc_ext_pin_window(struct tegra_dc_ext_user *user, u32 id,
 				   struct nvmap_handle_ref **handle,
 				   dma_addr_t *phys_addr);
@@ -78,4 +120,13 @@ extern int tegra_dc_ext_set_cursor_image(struct tegra_dc_ext_user *user,
 extern int tegra_dc_ext_set_cursor(struct tegra_dc_ext_user *user,
 				   struct tegra_dc_ext_cursor *);
 
+extern int tegra_dc_ext_control_init(void);
+
+extern int tegra_dc_ext_queue_hotplug(struct tegra_dc_ext_control *,
+				      int output);
+extern ssize_t tegra_dc_ext_event_read(struct file *filp, char __user *buf,
+				       size_t size, loff_t *ppos);
+
+extern int tegra_dc_ext_get_num_outputs(void);
+
 #endif /* __TEGRA_DC_EXT_PRIV_H */