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>

diff --git a/drivers/media/common/saa7146_core.c b/drivers/media/common/saa7146_core.c
index cb034ead95ab8e5b88d2867cecdf7a7d5fe566fc..7d04a6fd1acb03affddb06faada0a40018066a19 100644 (file)
--- 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
  ****************************************************************************/