media: am437x-vpfe: Rework ISR routine for clarity

Make the ISR code simpler to follow by removing goto and
relocating/eliminating duplicate spinlock accesses.
Signed-off-by: Benoit Parrot <bparrot@ti.com>
Acked-by: Lad Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

drivers/media/platform/am437x/am437x-vpfe.c

@@ -1233,22 +1233,29 @@ static int vpfe_open(struct file *file)
  * This function will get next buffer from the dma queue and
  * set the buffer address in the vpfe register for capture.
  * the buffer is marked active
- *
- * Assumes caller is holding vpfe->dma_queue_lock already
  */
-static inline void vpfe_schedule_next_buffer(struct vpfe_device *vpfe)
+static void vpfe_schedule_next_buffer(struct vpfe_device *vpfe)
 {
+	dma_addr_t addr;
+
+	spin_lock(&vpfe->dma_queue_lock);
+	if (list_empty(&vpfe->dma_queue)) {
+		spin_unlock(&vpfe->dma_queue_lock);
+		return;
+	}
+
 	vpfe->next_frm = list_entry(vpfe->dma_queue.next,
 				    struct vpfe_cap_buffer, list);
 	list_del(&vpfe->next_frm->list);
+	spin_unlock(&vpfe->dma_queue_lock);
 
-	vpfe_set_sdr_addr(&vpfe->ccdc,
-	       vb2_dma_contig_plane_dma_addr(&vpfe->next_frm->vb.vb2_buf, 0));
+	addr = vb2_dma_contig_plane_dma_addr(&vpfe->next_frm->vb.vb2_buf, 0);
+	vpfe_set_sdr_addr(&vpfe->ccdc, addr);
 }
 
 static inline void vpfe_schedule_bottom_field(struct vpfe_device *vpfe)
 {
-	unsigned long addr;
+	dma_addr_t addr;
 
 	addr = vb2_dma_contig_plane_dma_addr(&vpfe->next_frm->vb.vb2_buf, 0) +
 					vpfe->field_off;
@@ -1273,35 +1280,14 @@ static inline void vpfe_process_buffer_complete(struct vpfe_device *vpfe)
 	vpfe->cur_frm = vpfe->next_frm;
 }
 
-/*
- * vpfe_isr : ISR handler for vpfe capture (VINT0)
- * @irq: irq number
- * @dev_id: dev_id ptr
- *
- * It changes status of the captured buffer, takes next buffer from the queue
- * and sets its address in VPFE registers
- */
-static irqreturn_t vpfe_isr(int irq, void *dev)
+static void vpfe_handle_interlaced_irq(struct vpfe_device *vpfe,
+				       enum v4l2_field field)
 {
-	struct vpfe_device *vpfe = (struct vpfe_device *)dev;
-	enum v4l2_field field;
-	int intr_status;
 	int fid;
 
-	intr_status = vpfe_reg_read(&vpfe->ccdc, VPFE_IRQ_STS);
-
-	if (intr_status & VPFE_VDINT0) {
-		field = vpfe->fmt.fmt.pix.field;
-
-		if (field == V4L2_FIELD_NONE) {
-			/* handle progressive frame capture */
-			if (vpfe->cur_frm != vpfe->next_frm)
-				vpfe_process_buffer_complete(vpfe);
-			goto next_intr;
-		}
-
 	/* interlaced or TB capture check which field
-		   we are in hardware */
+	 * we are in hardware
+	 */
 	fid = vpfe_ccdc_getfid(&vpfe->ccdc);
 
 	/* switch the software maintained field id */
@@ -1316,6 +1302,7 @@ static irqreturn_t vpfe_isr(int irq, void *dev)
 			 */
 			if (vpfe->cur_frm != vpfe->next_frm)
 				vpfe_process_buffer_complete(vpfe);
+
 			/*
 			 * based on whether the two fields are stored
 			 * interleave or separately in memory,
@@ -1323,20 +1310,16 @@ static irqreturn_t vpfe_isr(int irq, void *dev)
 			 */
 			if (field == V4L2_FIELD_SEQ_TB)
 				vpfe_schedule_bottom_field(vpfe);
-
-				goto next_intr;
-			}
+		} else {
 			/*
 			 * if one field is just being captured configure
 			 * the next frame get the next frame from the empty
 			 * queue if no frame is available hold on to the
 			 * current buffer
 			 */
-			spin_lock(&vpfe->dma_queue_lock);
-			if (!list_empty(&vpfe->dma_queue) &&
-			    vpfe->cur_frm == vpfe->next_frm)
+			if (vpfe->cur_frm == vpfe->next_frm)
 				vpfe_schedule_next_buffer(vpfe);
-			spin_unlock(&vpfe->dma_queue_lock);
+		}
 	} else if (fid == 0) {
 		/*
 		 * out of sync. Recover from any hardware out-of-sync.
@@ -1344,16 +1327,37 @@ static irqreturn_t vpfe_isr(int irq, void *dev)
 		 */
 		vpfe->field = fid;
 	}
+}
+
+/*
+ * vpfe_isr : ISR handler for vpfe capture (VINT0)
+ * @irq: irq number
+ * @dev_id: dev_id ptr
+ *
+ * It changes status of the captured buffer, takes next buffer from the queue
+ * and sets its address in VPFE registers
+ */
+static irqreturn_t vpfe_isr(int irq, void *dev)
+{
+	struct vpfe_device *vpfe = (struct vpfe_device *)dev;
+	enum v4l2_field field = vpfe->fmt.fmt.pix.field;
+	int intr_status;
+
+	intr_status = vpfe_reg_read(&vpfe->ccdc, VPFE_IRQ_STS);
+
+	if (intr_status & VPFE_VDINT0) {
+		if (field == V4L2_FIELD_NONE) {
+			if (vpfe->cur_frm != vpfe->next_frm)
+				vpfe_process_buffer_complete(vpfe);
+		} else {
+			vpfe_handle_interlaced_irq(vpfe, field);
+		}
 	}
 
-next_intr:
 	if (intr_status & VPFE_VDINT1) {
-		spin_lock(&vpfe->dma_queue_lock);
-		if (vpfe->fmt.fmt.pix.field == V4L2_FIELD_NONE &&
-		    !list_empty(&vpfe->dma_queue) &&
+		if (field == V4L2_FIELD_NONE &&
 		    vpfe->cur_frm == vpfe->next_frm)
 			vpfe_schedule_next_buffer(vpfe);
-		spin_unlock(&vpfe->dma_queue_lock);
 	}
 
 	vpfe_clear_intr(&vpfe->ccdc, intr_status);