misc: tegra-profiler: add poll support

Tegra Profiler misc driver: add poll support

Bug 1374312

Change-Id: Id0844b3b329f348763f22b831fc73ac64f04fd9b
Signed-off-by: Igor Nabirushkin <inabirushkin@nvidia.com>
Reviewed-on: http://git-master/r/324078
(cherry picked from commit 5cf6aad33faf73a32d01aa9f4d064410c5a677b3)
Reviewed-on: http://git-master/r/340010
Reviewed-by: Harry Hong <hhong@nvidia.com>
Tested-by: Harry Hong <hhong@nvidia.com>

5 files changed, 43 insertions, 2 deletions

diff --git a/drivers/misc/tegra-profiler/comm.c b/drivers/misc/tegra-profiler/comm.c
index 9273d8ad8991..51a4abe9d566 100644
--- a/drivers/misc/tegra-profiler/comm.c
+++ b/drivers/misc/tegra-profiler/comm.c
@@ -23,6 +23,7 @@
 #include <linux/vmalloc.h>
 #include <linux/miscdevice.h>
 #include <linux/sched.h>
+#include <linux/poll.h>
 
 #include <linux/tegra_profiler.h>
 
@@ -92,6 +93,18 @@ static int rb_is_empty(struct quadd_ring_buffer *rb)
 	return rb->fill_count == 0;
 }
 
+static int rb_is_empty_lock(struct quadd_ring_buffer *rb)
+{
+	int res;
+	unsigned long flags;
+
+	spin_lock_irqsave(&rb->lock, flags);
+	res = rb->fill_count == 0;
+	spin_unlock_irqrestore(&rb->lock, flags);
+
+	return res;
+}
+
 static size_t
 rb_get_free_space(struct quadd_ring_buffer *rb)
 {
@@ -231,6 +244,8 @@ write_sample(struct quadd_record_data *sample, void *extra_data,
 		rb->max_fill_count = rb->fill_count;
 
 	spin_unlock_irqrestore(&rb->lock, flags);
+
+	wake_up_interruptible(&comm_ctx.read_wait);
 }
 
 static int read_sample(char __user *buffer, size_t max_length)
@@ -405,6 +420,23 @@ static int device_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
+static unsigned int
+device_poll(struct file *file, poll_table *wait)
+{
+	unsigned int mask = 0;
+	struct quadd_ring_buffer *rb = &comm_ctx.rb;
+
+	poll_wait(file, &comm_ctx.read_wait, wait);
+
+	if (!rb_is_empty_lock(rb))
+		mask |= POLLIN | POLLRDNORM;
+
+	if (!atomic_read(&comm_ctx.active))
+		mask |= POLLHUP;
+
+	return mask;
+}
+
 static ssize_t
 device_read(struct file *filp,
 	    char __user *buffer,
@@ -588,6 +620,7 @@ device_ioctl(struct file *file,
 	case IOCTL_STOP:
 		if (atomic_cmpxchg(&comm_ctx.active, 1, 0)) {
 			comm_ctx.control->stop();
+			wake_up_interruptible(&comm_ctx.read_wait);
 			rb_deinit(&comm_ctx.rb);
 			pr_info("Stop profiling success\n");
 		}
@@ -617,6 +650,7 @@ static void free_ctx(void)
 
 static const struct file_operations qm_fops = {
 	.read		= device_read,
+	.poll		= device_poll,
 	.open		= device_open,
 	.release	= device_release,
 	.unlocked_ioctl	= device_ioctl
@@ -651,6 +685,8 @@ static int comm_init(void)
 	comm_ctx.process_pid = 0;
 	comm_ctx.nr_users = 0;
 
+	init_waitqueue_head(&comm_ctx.read_wait);
+
 	return 0;
 }
 
diff --git a/drivers/misc/tegra-profiler/comm.h b/drivers/misc/tegra-profiler/comm.h
index f519f17b317c..956e44be90c3 100644
--- a/drivers/misc/tegra-profiler/comm.h
+++ b/drivers/misc/tegra-profiler/comm.h
@@ -67,6 +67,8 @@ struct quadd_comm_ctx {
 	pid_t process_pid;
 	uid_t debug_app_uid;
 
+	wait_queue_head_t read_wait;
+
 	struct miscdevice *misc_dev;
 };
 
diff --git a/drivers/misc/tegra-profiler/main.c b/drivers/misc/tegra-profiler/main.c
index 2b84dd036d81..f5238bb55eeb 100644
--- a/drivers/misc/tegra-profiler/main.c
+++ b/drivers/misc/tegra-profiler/main.c
@@ -356,7 +356,7 @@ static void get_capabilities(struct quadd_comm_cap *cap)
 
 	cap->tegra_lp_cluster = quadd_is_cpu_with_lp_cluster();
 	cap->power_rate = 1;
-	cap->blocked_read = 0;
+	cap->blocked_read = 1;
 }
 
 static void get_state(struct quadd_module_state *state)
diff --git a/drivers/misc/tegra-profiler/quadd_proc.c b/drivers/misc/tegra-profiler/quadd_proc.c
index 649c2d7065d5..02b4cb0e3fce 100644
--- a/drivers/misc/tegra-profiler/quadd_proc.c
+++ b/drivers/misc/tegra-profiler/quadd_proc.c
@@ -71,6 +71,9 @@ static int show_capabilities(struct seq_file *f, void *offset)
 			   YES_NO(cap->l2_multiple_events));
 	}
 
+	seq_printf(f, "support polling mode:   %s\n",
+		   YES_NO(cap->blocked_read));
+
 	seq_printf(f, "\n");
 	seq_printf(f, "Supported events:\n");
 	seq_printf(f, "cpu_cycles:             %s\n",
diff --git a/drivers/misc/tegra-profiler/version.h b/drivers/misc/tegra-profiler/version.h
index 2d55c518b506..91fade52fa57 100644
--- a/drivers/misc/tegra-profiler/version.h
+++ b/drivers/misc/tegra-profiler/version.h
@@ -18,7 +18,7 @@
 #ifndef __QUADD_VERSION_H
 #define __QUADD_VERSION_H
 
-#define QUADD_MODULE_VERSION		"1.32"
+#define QUADD_MODULE_VERSION		"1.33"
 #define QUADD_MODULE_BRANCH		"Dev"
 
 #endif	/* __QUADD_VERSION_H */