V4L/DVB (3669): Configurable dma buffer size for saa7146-based budget dvb cards

- Issue a warning when more than 80% of the DMA buffer is being used 
  (probably due to bad IRQ latency). Warnings are rate-limited.
- Introduce a new parameter 'bufsize' (in KByte) which increases the
  default DMA buffer of 188 KByte up to 1410 KByte (Activy: 564 KByte).

Signed-off-by: Ingo Schneider <mail@ingo-schneider.de>
Signed-off-by: Oliver Endriss <o.endriss@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

drivers/media/dvb/ttpci/budget-core.c

@@ -39,9 +39,21 @@
 #include "budget.h"
 #include "ttpci-eeprom.h"
 
+#define TS_WIDTH		(2 * TS_SIZE)
+#define TS_WIDTH_ACTIVY		TS_SIZE
+#define TS_HEIGHT_MASK		0xf00
+#define TS_HEIGHT_MASK_ACTIVY	0xc00
+#define TS_MIN_BUFSIZE_K	188
+#define TS_MAX_BUFSIZE_K	1410
+#define TS_MAX_BUFSIZE_K_ACTIVY	564
+#define BUFFER_WARNING_WAIT	(30*HZ)
+
 int budget_debug;
+static int dma_buffer_size = TS_MIN_BUFSIZE_K;
 module_param_named(debug, budget_debug, int, 0644);
+module_param_named(bufsize, dma_buffer_size, int, 0444);
 MODULE_PARM_DESC(debug, "Turn on/off budget debugging (default:off).");
+MODULE_PARM_DESC(bufsize, "DMA buffer size in KB, default: 188, min: 188, max: 1410 (Activy: 564)");
 
 /****************************************************************************
  * TT budget / WinTV Nova
@@ -70,11 +82,10 @@ static int start_ts_capture(struct budget *budget)
 
 	saa7146_write(dev, MC1, MASK_20);	// DMA3 off
 
-	memset(budget->grabbing, 0x00, TS_HEIGHT * TS_WIDTH);
+	memset(budget->grabbing, 0x00, budget->buffer_size);
 
 	saa7146_write(dev, PCI_BT_V1, 0x001c0000 | (saa7146_read(dev, PCI_BT_V1) & ~0x001f0000));
 
-	budget->tsf = 0xff;
 	budget->ttbp = 0;
 
 	/*
@@ -115,16 +126,12 @@ static int start_ts_capture(struct budget *budget)
 
 	saa7146_write(dev, BASE_ODD3, 0);
 	saa7146_write(dev, BASE_EVEN3, 0);
-	saa7146_write(dev, PROT_ADDR3, TS_WIDTH * TS_HEIGHT);
+	saa7146_write(dev, PROT_ADDR3, budget->buffer_size);
 	saa7146_write(dev, BASE_PAGE3, budget->pt.dma | ME1 | 0x90);
 
-	if (budget->card->type == BUDGET_FS_ACTIVY) {
+	saa7146_write(dev, PITCH3, budget->buffer_width);
-		saa7146_write(dev, PITCH3, TS_WIDTH / 2);
+	saa7146_write(dev, NUM_LINE_BYTE3,
-		saa7146_write(dev, NUM_LINE_BYTE3, ((TS_HEIGHT * 2) << 16) | (TS_WIDTH / 2));
+			(budget->buffer_height << 16) | budget->buffer_width);
-	} else {
-		saa7146_write(dev, PITCH3, TS_WIDTH);
-		saa7146_write(dev, NUM_LINE_BYTE3, (TS_HEIGHT << 16) | TS_WIDTH);
-	}
 
 	saa7146_write(dev, MC2, (MASK_04 | MASK_20));
 
@@ -141,11 +148,12 @@ static void vpeirq(unsigned long data)
 	u8 *mem = (u8 *) (budget->grabbing);
 	u32 olddma = budget->ttbp;
 	u32 newdma = saa7146_read(budget->dev, PCI_VDP3);
+	u32 count;
 
 	/* nearest lower position divisible by 188 */
 	newdma -= newdma % 188;
 
-	if (newdma >= TS_BUFLEN)
+	if (newdma >= budget->buffer_size)
 		return;
 
 	budget->ttbp = newdma;
@@ -154,11 +162,24 @@ static void vpeirq(unsigned long data)
 		return;
 
 	if (newdma > olddma) {	/* no wraparound, dump olddma..newdma */
-		dvb_dmx_swfilter_packets(&budget->demux, mem + olddma, (newdma - olddma) / 188);
+		count = newdma - olddma;
+		dvb_dmx_swfilter_packets(&budget->demux, mem + olddma, count / 188);
 	} else {		/* wraparound, dump olddma..buflen and 0..newdma */
-		dvb_dmx_swfilter_packets(&budget->demux, mem + olddma, (TS_BUFLEN - olddma) / 188);
+		count = budget->buffer_size - olddma;
+		dvb_dmx_swfilter_packets(&budget->demux, mem + olddma, count / 188);
+		count += newdma;
 		dvb_dmx_swfilter_packets(&budget->demux, mem, newdma / 188);
 	}
+
+	if (count > budget->buffer_warning_threshold)
+		budget->buffer_warnings++;
+
+	if (budget->buffer_warnings && time_after(jiffies, budget->buffer_warning_time)) {
+		printk("%s %s: used %d times >80%% of buffer (%u bytes now)\n",
+			budget->dev->name, __FUNCTION__, budget->buffer_warnings, count);
+		budget->buffer_warning_time = jiffies + BUFFER_WARNING_WAIT;
+		budget->buffer_warnings = 0;
+	}
 }
 
 
@@ -341,9 +362,10 @@ int ttpci_budget_init(struct budget *budget, struct saa7146_dev *dev,
 		      struct saa7146_pci_extension_data *info,
 		      struct module *owner)
 {
-	int length = TS_WIDTH * TS_HEIGHT;
 	int ret = 0;
 	struct budget_info *bi = info->ext_priv;
+	int max_bufsize;
+	int height_mask;
 
 	memset(budget, 0, sizeof(struct budget));
 
@@ -352,6 +374,32 @@ int ttpci_budget_init(struct budget *budget, struct saa7146_dev *dev,
 	budget->card = bi;
 	budget->dev = (struct saa7146_dev *) dev;
 
+	if (budget->card->type == BUDGET_FS_ACTIVY) {
+		budget->buffer_width = TS_WIDTH_ACTIVY;
+		max_bufsize = TS_MAX_BUFSIZE_K_ACTIVY;
+		height_mask = TS_HEIGHT_MASK_ACTIVY;
+	} else {
+		budget->buffer_width = TS_WIDTH;
+		max_bufsize = TS_MAX_BUFSIZE_K;
+		height_mask = TS_HEIGHT_MASK;
+	}
+
+	if (dma_buffer_size < TS_MIN_BUFSIZE_K)
+		dma_buffer_size = TS_MIN_BUFSIZE_K;
+	else if (dma_buffer_size > max_bufsize)
+		dma_buffer_size = max_bufsize;
+
+	budget->buffer_height = dma_buffer_size * 1024 / budget->buffer_width;
+	budget->buffer_height &= height_mask;
+	budget->buffer_size = budget->buffer_height * budget->buffer_width;
+	budget->buffer_warning_threshold = budget->buffer_size * 80/100;
+	budget->buffer_warnings = 0;
+	budget->buffer_warning_time = jiffies;
+
+	dprintk(2, "%s: width = %d, height = %d\n",
+		budget->dev->name, budget->buffer_width, budget->buffer_height);
+	printk("%s: dma buffer size %u\n", budget->dev->name, budget->buffer_size);
+
 	dvb_register_adapter(&budget->dvb_adapter, budget->card->name, owner);
 
 	/* set dd1 stream a & b */
@@ -392,7 +440,7 @@ int ttpci_budget_init(struct budget *budget, struct saa7146_dev *dev,
 	ttpci_eeprom_parse_mac(&budget->i2c_adap, budget->dvb_adapter.proposed_mac);
 
 	if (NULL ==
-	    (budget->grabbing = saa7146_vmalloc_build_pgtable(dev->pci, length, &budget->pt))) {
+	    (budget->grabbing = saa7146_vmalloc_build_pgtable(dev->pci, budget->buffer_size, &budget->pt))) {
 		ret = -ENOMEM;
 		goto err;
 	}

drivers/media/dvb/ttpci/budget-patch.c

@@ -577,20 +577,6 @@ static int budget_patch_attach (struct saa7146_dev* dev, struct saa7146_pci_exte
 	saa7146_setgpio(dev, 3, SAA7146_GPIO_OUTLO);
 	// Set RPS1 Address register to point to RPS code               (r108 p42)
 	saa7146_write(dev, RPS_ADDR1, dev->d_rps1.dma_handle);
-	// Set Source Line Counter Threshold, using BRS                 (rCC p43)
-	// It generates HS event every TS_HEIGHT lines
-	// this is related to TS_WIDTH set in register
-	// NUM_LINE_BYTE3 in budget-core.c. If NUM_LINE_BYTE
-	// low 16 bits are set to TS_WIDTH bytes (TS_WIDTH=2*188
-	//,then RPS_THRESH1
-	// should be set to trigger every TS_HEIGHT (512) lines.
-	//
-	saa7146_write(dev, RPS_THRESH1, (TS_HEIGHT*1) | MASK_12 );
-
-	// saa7146_write(dev, RPS_THRESH0, ((TS_HEIGHT/2)<<16) |MASK_28| (TS_HEIGHT/2) |MASK_12 );
-	// Enable RPS1                                                  (rFC p33)
-	saa7146_write(dev, MC1, (MASK_13 | MASK_29));
-
 
 	if (!(budget = kmalloc (sizeof(struct budget_patch), GFP_KERNEL)))
 		return -ENOMEM;
@@ -602,6 +588,20 @@ static int budget_patch_attach (struct saa7146_dev* dev, struct saa7146_pci_exte
 		return err;
 	}
 
+	// Set Source Line Counter Threshold, using BRS                 (rCC p43)
+	// It generates HS event every TS_HEIGHT lines
+	// this is related to TS_WIDTH set in register
+	// NUM_LINE_BYTE3 in budget-core.c. If NUM_LINE_BYTE
+	// low 16 bits are set to TS_WIDTH bytes (TS_WIDTH=2*188
+	//,then RPS_THRESH1
+	// should be set to trigger every TS_HEIGHT (512) lines.
+	//
+	saa7146_write(dev, RPS_THRESH1, budget->buffer_height | MASK_12 );
+
+	// saa7146_write(dev, RPS_THRESH0, ((TS_HEIGHT/2)<<16) |MASK_28| (TS_HEIGHT/2) |MASK_12 );
+	// Enable RPS1                                                  (rFC p33)
+	saa7146_write(dev, MC1, (MASK_13 | MASK_29));
+
 
 	dev->ext_priv = budget;
 

drivers/media/dvb/ttpci/budget.h

@@ -58,7 +58,13 @@ struct budget {
 	int ci_present;
 	int video_port;
 
-	u8 tsf;
+	u32 buffer_width;
+	u32 buffer_height;
+	u32 buffer_size;
+	u32 buffer_warning_threshold;
+	u32 buffer_warnings;
+	unsigned long buffer_warning_time;
+
 	u32 ttbp;
 	int feeding;
 
@@ -79,11 +85,6 @@ static struct saa7146_pci_extension_data x_var = { \
 	.ext_priv = &x_var ## _info, \
 	.ext = &budget_extension };
 
-#define TS_WIDTH  (376)
-#define TS_HEIGHT (512)
-#define TS_BUFLEN (TS_WIDTH*TS_HEIGHT)
-#define TS_MAX_PACKETS (TS_BUFLEN/TS_SIZE)
-
 #define BUDGET_TT		   0
 #define BUDGET_TT_HW_DISEQC	   1
 #define BUDGET_PATCH		   3