V4L/DVB (5675): Move big PIO accesses from the interrupt handler to a workhandler

Sliced VBI transfers use PIO instead of DMA. This was done inside the
interrupt handler, but since PIO accesses are very slow this meant that
a lot of time was spent inside the interrupt handler. All PIO copies are
now moved to a workqueue. This should fix various issues with missing time
ticks and remote key hits.
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/video/ivtv/ivtv-driver.c

@@ -652,6 +652,7 @@ static int __devinit ivtv_init_struct1(struct ivtv *itv)
 	itv->dma_timer.data = (unsigned long)itv;
 
 	itv->cur_dma_stream = -1;
+	itv->cur_pio_stream = -1;
 	itv->audio_stereo_mode = AUDIO_STEREO;
 	itv->audio_bilingual_mode = AUDIO_MONO_LEFT;
 

drivers/media/video/ivtv/ivtv-driver.h

@@ -237,6 +237,7 @@ extern const u32 yuv_offset[4];
 #define IVTV_IRQ_ENC_VBI_CAP		(0x1 << 29)
 #define IVTV_IRQ_ENC_VIM_RST		(0x1 << 28)
 #define IVTV_IRQ_ENC_DMA_COMPLETE	(0x1 << 27)
+#define IVTV_IRQ_ENC_PIO_COMPLETE	(0x1 << 25)
 #define IVTV_IRQ_DEC_AUD_MODE_CHG	(0x1 << 24)
 #define IVTV_IRQ_DEC_DATA_REQ		(0x1 << 22)
 #define IVTV_IRQ_DEC_DMA_COMPLETE	(0x1 << 20)
@@ -247,7 +248,8 @@ extern const u32 yuv_offset[4];
 #define IVTV_IRQ_DEC_VSYNC		(0x1 << 10)
 
 /* IRQ Masks */
-#define IVTV_IRQ_MASK_INIT (IVTV_IRQ_DMA_ERR|IVTV_IRQ_ENC_DMA_COMPLETE|IVTV_IRQ_DMA_READ)
+#define IVTV_IRQ_MASK_INIT (IVTV_IRQ_DMA_ERR|IVTV_IRQ_ENC_DMA_COMPLETE|\
+		IVTV_IRQ_DMA_READ|IVTV_IRQ_ENC_PIO_COMPLETE)
 
 #define IVTV_IRQ_MASK_CAPTURE (IVTV_IRQ_ENC_START_CAP | IVTV_IRQ_ENC_EOS)
 #define IVTV_IRQ_MASK_DECODE  (IVTV_IRQ_DEC_DATA_REQ|IVTV_IRQ_DEC_AUD_MODE_CHG)
@@ -374,6 +376,9 @@ struct ivtv_mailbox_data {
 #define IVTV_F_S_STREAMOFF	7	/* signal end of stream EOS */
 #define IVTV_F_S_APPL_IO        8	/* this stream is used read/written by an application */
 
+#define IVTV_F_S_PIO_PENDING	9	/* this stream has pending PIO */
+#define IVTV_F_S_PIO_HAS_VBI	1       /* the current PIO request also requests VBI data */
+
 /* per-ivtv, i_flags */
 #define IVTV_F_I_DMA		   0 	/* DMA in progress */
 #define IVTV_F_I_UDMA		   1 	/* UDMA in progress */
@@ -390,8 +395,11 @@ struct ivtv_mailbox_data {
 #define IVTV_F_I_DECODING_YUV	   12 	/* this stream is YUV frame decoding */
 #define IVTV_F_I_ENC_PAUSED	   13 	/* the encoder is paused */
 #define IVTV_F_I_VALID_DEC_TIMINGS 14 	/* last_dec_timing is valid */
-#define IVTV_F_I_WORK_HANDLER_VBI  15	/* there is work to be done for VBI */
-#define IVTV_F_I_WORK_HANDLER_YUV  16	/* there is work to be done for YUV */
+#define IVTV_F_I_HAVE_WORK  	   15	/* Used in the interrupt handler: there is work to be done */
+#define IVTV_F_I_WORK_HANDLER_VBI  16	/* there is work to be done for VBI */
+#define IVTV_F_I_WORK_HANDLER_YUV  17	/* there is work to be done for YUV */
+#define IVTV_F_I_WORK_HANDLER_PIO  18	/* there is work to be done for PIO */
+#define IVTV_F_I_PIO		   19	/* PIO in progress */
 
 /* Event notifications */
 #define IVTV_F_I_EV_DEC_STOPPED	   28	/* decoder stopped event */
@@ -484,6 +492,7 @@ struct ivtv_stream {
 
 	/* Base Dev SG Array for cx23415/6 */
 	struct ivtv_SG_element *SGarray;
+	struct ivtv_SG_element *PIOarray;
 	dma_addr_t SG_handle;
 	int SG_length;
 
@@ -706,6 +715,7 @@ struct ivtv {
 	atomic_t decoding;	/* count number of active decoding streams */
 	u32 irq_rr_idx; /* Round-robin stream index */
 	int cur_dma_stream;	/* index of stream doing DMA */
+	int cur_pio_stream;	/* index of stream doing PIO */
 	u32 dma_data_req_offset;
 	u32 dma_data_req_size;
 	int output_mode;        /* NONE, MPG, YUV, UDMA YUV, passthrough */

drivers/media/video/ivtv/ivtv-queue.c

@@ -195,14 +195,26 @@ int ivtv_stream_alloc(struct ivtv_stream *s)
 		s->dma != PCI_DMA_NONE ? "DMA " : "",
 		s->name, s->buffers, s->buf_size, s->buffers * s->buf_size / 1024);
 
-	/* Allocate DMA SG Arrays */
-	if (s->dma != PCI_DMA_NONE) {
-		s->SGarray = (struct ivtv_SG_element *)kzalloc(SGsize, GFP_KERNEL);
-		if (s->SGarray == NULL) {
-			IVTV_ERR("Could not allocate SGarray for %s stream\n", s->name);
+	if (ivtv_might_use_pio(s)) {
+		s->PIOarray = (struct ivtv_SG_element *)kzalloc(SGsize, GFP_KERNEL);
+		if (s->PIOarray == NULL) {
+			IVTV_ERR("Could not allocate PIOarray for %s stream\n", s->name);
 			return -ENOMEM;
 		}
-		s->SG_length = 0;
+	}
+
+	/* Allocate DMA SG Arrays */
+	s->SGarray = (struct ivtv_SG_element *)kzalloc(SGsize, GFP_KERNEL);
+	if (s->SGarray == NULL) {
+		IVTV_ERR("Could not allocate SGarray for %s stream\n", s->name);
+		if (ivtv_might_use_pio(s)) {
+			kfree(s->PIOarray);
+			s->PIOarray = NULL;
+		}
+		return -ENOMEM;
+	}
+	s->SG_length = 0;
+	if (ivtv_might_use_dma(s)) {
 		s->SG_handle = pci_map_single(itv->dev, s->SGarray, SGsize, s->dma);
 		ivtv_stream_sync_for_cpu(s);
 	}
@@ -219,7 +231,7 @@ int ivtv_stream_alloc(struct ivtv_stream *s)
 			break;
 		}
 		INIT_LIST_HEAD(&buf->list);
-		if (s->dma != PCI_DMA_NONE) {
+		if (ivtv_might_use_dma(s)) {
 			buf->dma_handle = pci_map_single(s->itv->dev,
 				buf->buf, s->buf_size + 256, s->dma);
 			ivtv_buf_sync_for_cpu(s, buf);
@@ -242,7 +254,7 @@ void ivtv_stream_free(struct ivtv_stream *s)
 
 	/* empty q_free */
 	while ((buf = ivtv_dequeue(s, &s->q_free))) {
-		if (s->dma != PCI_DMA_NONE)
+		if (ivtv_might_use_dma(s))
 			pci_unmap_single(s->itv->dev, buf->dma_handle,
 				s->buf_size + 256, s->dma);
 		kfree(buf->buf);
@@ -256,6 +268,9 @@ void ivtv_stream_free(struct ivtv_stream *s)
 				 sizeof(struct ivtv_SG_element) * s->buffers, PCI_DMA_TODEVICE);
 			s->SG_handle = IVTV_DMA_UNMAPPED;
 		}
+		kfree(s->SGarray);
+		kfree(s->PIOarray);
+		s->PIOarray = NULL;
 		s->SGarray = NULL;
 		s->SG_length = 0;
 	}

drivers/media/video/ivtv/ivtv-queue.h

@@ -20,18 +20,43 @@
  */
 
 #define IVTV_DMA_UNMAPPED	((u32) -1)
+#define SLICED_VBI_PIO 1
 
 /* ivtv_buffer utility functions */
+
+static inline int ivtv_might_use_pio(struct ivtv_stream *s)
+{
+	return s->dma == PCI_DMA_NONE || (SLICED_VBI_PIO && s->type == IVTV_ENC_STREAM_TYPE_VBI);
+}
+
+static inline int ivtv_use_pio(struct ivtv_stream *s)
+{
+	struct ivtv *itv = s->itv;
+
+	return s->dma == PCI_DMA_NONE ||
+	    (SLICED_VBI_PIO && s->type == IVTV_ENC_STREAM_TYPE_VBI && itv->vbi.sliced_in->service_set);
+}
+
+static inline int ivtv_might_use_dma(struct ivtv_stream *s)
+{
+	return s->dma != PCI_DMA_NONE;
+}
+
+static inline int ivtv_use_dma(struct ivtv_stream *s)
+{
+	return !ivtv_use_pio(s);
+}
+
 static inline void ivtv_buf_sync_for_cpu(struct ivtv_stream *s, struct ivtv_buffer *buf)
 {
-	if (s->dma != PCI_DMA_NONE)
+	if (ivtv_use_dma(s))
 		pci_dma_sync_single_for_cpu(s->itv->dev, buf->dma_handle,
 				s->buf_size + 256, s->dma);
 }
 
 static inline void ivtv_buf_sync_for_device(struct ivtv_stream *s, struct ivtv_buffer *buf)
 {
-	if (s->dma != PCI_DMA_NONE)
+	if (ivtv_use_dma(s))
 		pci_dma_sync_single_for_device(s->itv->dev, buf->dma_handle,
 				s->buf_size + 256, s->dma);
 }
@@ -53,12 +78,14 @@ void ivtv_stream_free(struct ivtv_stream *s);
 
 static inline void ivtv_stream_sync_for_cpu(struct ivtv_stream *s)
 {
-	pci_dma_sync_single_for_cpu(s->itv->dev, s->SG_handle,
-		sizeof(struct ivtv_SG_element) * s->buffers, PCI_DMA_TODEVICE);
+	if (ivtv_use_dma(s))
+		pci_dma_sync_single_for_cpu(s->itv->dev, s->SG_handle,
+			sizeof(struct ivtv_SG_element) * s->buffers, PCI_DMA_TODEVICE);
 }
 
 static inline void ivtv_stream_sync_for_device(struct ivtv_stream *s)
 {
-	pci_dma_sync_single_for_device(s->itv->dev, s->SG_handle,
-		sizeof(struct ivtv_SG_element) * s->buffers, PCI_DMA_TODEVICE);
+	if (ivtv_use_dma(s))
+		pci_dma_sync_single_for_device(s->itv->dev, s->SG_handle,
+			sizeof(struct ivtv_SG_element) * s->buffers, PCI_DMA_TODEVICE);
 }

drivers/media/video/ivtv/ivtv-vbi.c

@@ -450,7 +450,7 @@ void ivtv_disable_vbi(struct ivtv *itv)
 }
 
 
-void vbi_work_handler(struct ivtv *itv)
+void ivtv_vbi_work_handler(struct ivtv *itv)
 {
 	struct v4l2_sliced_vbi_data data;
 

drivers/media/video/ivtv/ivtv-vbi.h

@@ -23,4 +23,4 @@ void ivtv_process_vbi_data(struct ivtv *itv, struct ivtv_buffer *buf,
 int ivtv_used_line(struct ivtv *itv, int line, int field);
 void ivtv_disable_vbi(struct ivtv *itv);
 void ivtv_set_vbi(unsigned long arg);
-void vbi_work_handler(struct ivtv *itv);
+void ivtv_vbi_work_handler(struct ivtv *itv);