V4L/DVB (6495): saa7146: saa7146_wait_for_debi_done fixes

Two fixes for the 'saa7146_wait_for_debi_done' code:
(a) Timeout did not work when the routine was called with
    interrupts disabled.
(b) Reduce PCI I/O load caused by saa7146_wait_for_debi_done.
    Seems to be very important on fast machines!

Based on code posted by Hartmut Birr @vdr-portal.


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

1 files changed, 58 insertions, 12 deletions

diff --git a/drivers/media/common/saa7146_core.c b/drivers/media/common/saa7146_core.c
index cb034ead95ab..7d04a6fd1acb 100644
--- a/drivers/media/common/saa7146_core.c
+++ b/drivers/media/common/saa7146_core.c
@@ -59,43 +59,89 @@ void saa7146_setgpio(struct saa7146_dev *dev, int port, u32 data)
 }
 
 /* This DEBI code is based on the saa7146 Stradis driver by Nathan Laredo */
-int saa7146_wait_for_debi_done(struct saa7146_dev *dev, int nobusyloop)
+static inline int saa7146_wait_for_debi_done_sleep(struct saa7146_dev *dev,
+                                unsigned long us1, unsigned long us2)
 {
-        unsigned long start;
+        unsigned long timeout;
         int err;
 
         /* wait for registers to be programmed */
-        start = jiffies;
+        timeout = jiffies + usecs_to_jiffies(us1);
         while (1) {
-                err = time_after(jiffies, start + HZ/20);
+                err = time_after(jiffies, timeout);
                 if (saa7146_read(dev, MC2) & 2)
                         break;
                 if (err) {
-                        DEB_S(("timed out while waiting for registers getting programmed\n"));
+                        printk(KERN_ERR "%s: %s timed out while waiting for "
+                                        "registers getting programmed\n",
+                                        dev->name, __FUNCTION__);
                         return -ETIMEDOUT;
                 }
-                if (nobusyloop)
-                        msleep(1);
+                msleep(1);
         }
 
         /* wait for transfer to complete */
-        start = jiffies;
+        timeout = jiffies + usecs_to_jiffies(us2);
         while (1) {
-                err = time_after(jiffies, start + HZ/4);
+                err = time_after(jiffies, timeout);
                 if (!(saa7146_read(dev, PSR) & SPCI_DEBI_S))
                         break;
                 saa7146_read(dev, MC2);
                 if (err) {
-                        DEB_S(("timed out while waiting for transfer completion\n"));
+                        DEB_S(("%s: %s timed out while waiting for transfer "
+                                "completion\n", dev->name, __FUNCTION__));
                         return -ETIMEDOUT;
                 }
-                if (nobusyloop)
-                        msleep(1);
+                msleep(1);
         }
 
         return 0;
 }
 
+static inline int saa7146_wait_for_debi_done_busyloop(struct saa7146_dev *dev,
+                                unsigned long us1, unsigned long us2)
+{
+        unsigned long loops;
+
+        /* wait for registers to be programmed */
+        loops = us1;
+        while (1) {
+                if (saa7146_read(dev, MC2) & 2)
+                        break;
+                if (!loops--) {
+                        printk(KERN_ERR "%s: %s timed out while waiting for "
+                                        "registers getting programmed\n",
+                                        dev->name, __FUNCTION__);
+                        return -ETIMEDOUT;
+                }
+                udelay(1);
+        }
+
+        /* wait for transfer to complete */
+        loops = us2 / 5;
+        while (1) {
+                if (!(saa7146_read(dev, PSR) & SPCI_DEBI_S))
+                        break;
+                saa7146_read(dev, MC2);
+                if (!loops--) {
+                        DEB_S(("%s: %s timed out while waiting for transfer "
+                                "completion\n", dev->name, __FUNCTION__));
+                        return -ETIMEDOUT;
+                }
+                udelay(5);
+        }
+
+        return 0;
+}
+
+int saa7146_wait_for_debi_done(struct saa7146_dev *dev, int nobusyloop)
+{
+        if (nobusyloop)
+                return saa7146_wait_for_debi_done_sleep(dev, 50000, 250000);
+        else
+                return saa7146_wait_for_debi_done_busyloop(dev, 50000, 250000);
+}
+
 /****************************************************************************
  * general helper functions
  ****************************************************************************/