poll implemented but not tested

remoteproc-shm.c

@@ -9,8 +9,6 @@
  * (at your option) any later version.
  */
 
-/* kern_select() */
-
 #include <linux/debugfs.h>
 #include <linux/err.h>
 #include <linux/fs.h>
@@ -32,10 +30,14 @@
 
 #include <linux/interrupt.h>
 #include <linux/delay.h>
+#include <linux/wait.h>
+#include <stdbool.h>
 
 #define DRIVER_NAME "remoteproc-shm"
 #define SHM_SIZE 0x800000
 
+/* TODO: Semaphore */
+
 struct rproc_shm_device {
 	struct device		*dev;
 	struct mbox_chan	*mbox_channel;
@@ -46,11 +48,14 @@ struct rproc_shm_device {
 	struct device		*cdev;
 	int 			major;
 	struct fasync_struct	*async_queue;
+	bool			interrupted;
+	//sem_t			sem;
 };
 
 struct class *rproc_class = NULL;
 struct rproc_shm_device *dev;
 static struct dentry *root_debugfs_dir;
+static wait_queue_head_t *wait_queue;
 
 static void rproc_shm_receive_message(struct mbox_client *client, void *message)
 {
@@ -63,10 +68,15 @@ static void rproc_shm_receive_message(struct mbox_client *client, void *message)
 	if(dev->async_queue) {
 		dev_info(client->dev, "dev->async_queue == True\n");
 		kill_fasync(&dev->async_queue, SIGIO, POLL_IN);
+		dev_info(client->dev, "After kill_fasync\n");
 	}
 	else {
 		dev_info(client->dev, "dev->async_queue == FALSE\n");
 	}
+
+	dev->interrupted = true;
+
+	wake_up_interruptible(wait_queue);
 }
 
 static void rproc_shm_message_sent(struct mbox_client *client, void *message, int r)
@@ -211,9 +221,17 @@ static int rproc_shm_fasync(int fd, struct file *filp, int mode)
 
 static unsigned int rproc_shm_poll(struct file *filp, struct poll_table_struct *poll_table) 
 {
+	unsigned int mask = 0;
+
 	printk(KERN_INFO "rproc_shm_poll");
+	
+	poll_wait(filp, wait_queue, poll_table);
 
-	return 0;
+	dev->interrupted = false;
+	
+	mask |= POLLIN | POLLRDNORM; /* readable */
+
+	return mask;
 }
 
 static int rproc_shm_open(struct inode *i, struct file *filp) 
@@ -327,6 +345,8 @@ static int rproc_shm_probe(struct platform_device *pdev)
 	dev->shm_addr = virt_addr;
 	dev->dma_handle = dma;
 
+	init_waitqueue_head(wait_queue);
+
 	ret = rproc_shm_add_debugfs(pdev, dev);
 	if (ret)
 		return ret;
@@ -361,7 +381,7 @@ static int rproc_shm_remove(struct platform_device *pdev)
 	dev_info(&pdev->dev, "ADDRESS OF PTR: %p\n", virt_addr);
 	dev_info(&pdev->dev, "ADDRESS OF DMA: %x\n", dma);
 
-	/* reset fasync
+	/* reset fasync 
 	rproc_shm_fasync(-1, filp, 0);
 	*/