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>

1 files changed, 63 insertions, 15 deletions

diff --git a/drivers/media/dvb/ttpci/budget-core.c b/drivers/media/dvb/ttpci/budget-core.c
index 633e68c341c8..ea2066d461fc 100644
--- a/drivers/media/dvb/ttpci/budget-core.c
+++ b/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, TS_WIDTH / 2);
-                saa7146_write(dev, NUM_LINE_BYTE3, ((TS_HEIGHT * 2) << 16) | (TS_WIDTH / 2));
-        } else {
-                saa7146_write(dev, PITCH3, TS_WIDTH);
-                saa7146_write(dev, NUM_LINE_BYTE3, (TS_HEIGHT << 16) | TS_WIDTH);
-        }
+        saa7146_write(dev, PITCH3, budget->buffer_width);
+        saa7146_write(dev, NUM_LINE_BYTE3,
+                        (budget->buffer_height << 16) | budget->buffer_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;
         }