Use separate wait queue for each port in circbuf

Now each channel has its own instance of wait queue to prevent race
conditions when one channel wakes up the queue while the other channel
is processing interrupt and moved its write pointer, but has not
finished all other functions yet (i.e. filling interframe parameters).

src/drivers/elphel/circbuf.c

@@ -50,8 +50,11 @@
 /** @brief Driver name displayed in system logs */
 //#define CIRCBUF_DRIVER_NAME "circbuf driver"
 
-/** @brief Wait queue for the processes waiting for a new frame to appear in the circular buffer */
-wait_queue_head_t circbuf_wait_queue;
+/** @brief Wait queue for the processes waiting for a new frame to appear in the circular buffer. Each channel has
+ * its own instance of wait queue to prevent race conditions when one channel wakes up the queue while the other
+ * channel is processing interrupt and moved its write pointer, but has not finished all other functions yet.
+ */
+wait_queue_head_t circbuf_wait_queue[SENSOR_PORTS];
 struct circbuf_priv_t circbuf_priv[SENSOR_PORTS];
 struct circbuf_priv_t *circbuf_priv_ptr = circbuf_priv;
 /** @brief Global pointer to basic device structure. This pointer is used in debugfs output functions */
@@ -690,13 +693,13 @@ loff_t circbuf_lseek(struct file * file, loff_t offset, int orig) {
              break;
           case LSEEK_CIRC_WAIT:
               while (((fvld=circbufValidPointer(file->f_pos, &fp, chn)))==0) { //! only while not ready, ready or BAD - return
-                wait_event_interruptible (circbuf_wait_queue,(camSeqGetJPEG_wp(chn)<<2)!=file->f_pos);
+                wait_event_interruptible (circbuf_wait_queue[chn],(camSeqGetJPEG_wp(chn)<<2)!=file->f_pos);
               }
               if (fvld < 0) return -ESPIPE;      //!invalid seek - have better code?
               return file->f_pos ; //! data already available, return file pointer
           default:
             if ((offset & ~0x1f)==LSEEK_DAEMON_CIRCBUF) {
-              wait_event_interruptible (circbuf_wait_queue, get_imageParamsFrame(chn, P_DAEMON_EN, camSeqGetJPEG_frame(chn)) & (1<<(offset & 0x1f)));
+              wait_event_interruptible (circbuf_wait_queue[chn], get_imageParamsFrame(chn, P_DAEMON_EN, camSeqGetJPEG_frame(chn)) & (1<<(offset & 0x1f)));
             }
         }
         dev_dbg(g_dev_ptr, "return SEEK_END file->f_pos =0x%08llx\n",file->f_pos);
@@ -835,7 +838,7 @@ unsigned int circbuf_poll (struct file *file, poll_table *wait)
 		return POLLIN | POLLRDNORM;     // there was frame already available
 	} else {
 		// pointer valid, no frame yet
-		poll_wait(file, &circbuf_wait_queue, wait);
+		poll_wait(file, &circbuf_wait_queue[chn], wait);
 		// Frame might become available during call to poll_wait so nobody will wake us up,
 		// let's see if there is still no frame.
 		w_ptr = camseq_get_jpeg_wp(chn) << 2;
@@ -863,7 +866,7 @@ static struct file_operations circbuf_fops = {
  */
 static int circbuf_all_init(struct platform_device *pdev)
 {
-   int res;
+   int res, i;
    struct device *dev = &pdev->dev;
    const struct of_device_id *match;
 
@@ -897,7 +900,8 @@ static int circbuf_all_init(struct platform_device *pdev)
    }
 
    dev_dbg(dev, "initialize circbuf wait queue\n");
-   init_waitqueue_head(&circbuf_wait_queue);
+   for (i = 0; i < SENSOR_PORTS; i++)
+	   init_waitqueue_head(&circbuf_wait_queue[i]);
    dev_dbg(dev, "initialize Huffman tables with default data\n");
 
    g_dev_ptr = dev;

src/drivers/elphel/circbuf.h

@@ -40,7 +40,7 @@ struct circbuf_priv_t {
 };
 struct  circbuf_priv_t *get_circbuf(int chn); // alternative to use of extern struct circbuf_priv_ptr;
 extern struct circbuf_priv_t *circbuf_priv_ptr;
-extern wait_queue_head_t circbuf_wait_queue;
+extern wait_queue_head_t circbuf_wait_queue[SENSOR_PORTS];
 
 int          circbuf_all_open  (struct inode *inode,  struct file *filp); // set file size
 int          circbuf_all_release(struct inode *inode, struct file *filp);

src/drivers/elphel/sensor_common.c

@@ -694,7 +694,7 @@ static irqreturn_t compressor_irq_handler(int irq, void *dev_id)
  * @brief Tasklet - software interrupt
  * lower priority tasks
  * try to implement some balancing - if job is not finished - reduce FPS for it (alternate jobs)?
- * @param arg not used
+ * @param arg sensor port number
  */
 
 void tasklet_compressor_function(unsigned long arg)
@@ -724,7 +724,7 @@ void tasklet_compressor_function(unsigned long arg)
         outer_inv_range(phys_addr_start, phys_addr_end);
         __cpuc_flush_dcache_area(virt_addr_start, sz - ccam_dma_size);
     }
-    wake_up_interruptible(&circbuf_wait_queue); // should be done in here (after cache invalidation), not in ISR
+    wake_up_interruptible(&circbuf_wait_queue[arg]); // should be done in here (after cache invalidation), not in ISR
 }
 
 /*!TODO: