[ALSA] This simplifies and fixes waiting loops of the mce_down()

function after Trent Piepho's patch for AD1848.
It also makes busy_wait() function call not atomic.

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>

1 files changed, 19 insertions, 40 deletions

diff --git a/sound/sparc/cs4231.c b/sound/sparc/cs4231.c
index 9785382a5f39..f8c7a120ccbb 100644
--- a/sound/sparc/cs4231.c
+++ b/sound/sparc/cs4231.c
@@ -400,65 +400,44 @@ static void snd_cs4231_mce_up(struct snd_cs4231 *chip)
 
 static void snd_cs4231_mce_down(struct snd_cs4231 *chip)
 {
-        unsigned long flags;
-        unsigned long end_time;
-        int timeout;
+        unsigned long flags, timeout;
+        int reg;
 
-        spin_lock_irqsave(&chip->lock, flags);
         snd_cs4231_busy_wait(chip);
+        spin_lock_irqsave(&chip->lock, flags);
 #ifdef CONFIG_SND_DEBUG
         if (__cs4231_readb(chip, CS4231U(chip, REGSEL)) & CS4231_INIT)
                 snd_printdd("mce_down [%p] - auto calibration time out (0)\n",
                             CS4231U(chip, REGSEL));
 #endif
         chip->mce_bit &= ~CS4231_MCE;
-        timeout = __cs4231_readb(chip, CS4231U(chip, REGSEL));
-        __cs4231_writeb(chip, chip->mce_bit | (timeout & 0x1f),
+        reg = __cs4231_readb(chip, CS4231U(chip, REGSEL));
+        __cs4231_writeb(chip, chip->mce_bit | (reg & 0x1f),
                         CS4231U(chip, REGSEL));
-        if (timeout == 0x80)
-                snd_printdd("mce_down [%p]: serious init problem - "
-                            "codec still busy\n",
-                            chip->port);
-        if ((timeout & CS4231_MCE) == 0) {
+        if (reg == 0x80)
+                snd_printdd("mce_down [%p]: serious init problem "
+                            "- codec still busy\n", chip->port);
+        if ((reg & CS4231_MCE) == 0) {
                 spin_unlock_irqrestore(&chip->lock, flags);
                 return;
         }
 
         /*
-         * Wait for (possible -- during init auto-calibration may not be set)
-         * calibration process to start. Needs upto 5 sample periods on AD1848
-         * which at the slowest possible rate of 5.5125 kHz means 907 us.
+         * Wait for auto-calibration (AC) process to finish, i.e. ACI to go low.
          */
-        msleep(1);
-
-        /* check condition up to 250ms */
-        end_time = jiffies + msecs_to_jiffies(250);
-        while (snd_cs4231_in(chip, CS4231_TEST_INIT) &
-                CS4231_CALIB_IN_PROGRESS) {
-
+        timeout = jiffies + msecs_to_jiffies(250);
+        do {
                 spin_unlock_irqrestore(&chip->lock, flags);
-                if (time_after(jiffies, end_time)) {
-                        snd_printk("mce_down - "
-                                   "auto calibration time out (2)\n");
-                        return;
-                }
-                msleep(1);
-                spin_lock_irqsave(&chip->lock, flags);
-        }
-
-        /* check condition up to 100ms */
-        end_time = jiffies + msecs_to_jiffies(100);
-        while (__cs4231_readb(chip, CS4231U(chip, REGSEL)) & CS4231_INIT) {
-                spin_unlock_irqrestore(&chip->lock, flags);
-                if (time_after(jiffies, end_time)) {
-                        snd_printk("mce_down - "
-                                   "auto calibration time out (3)\n");
-                        return;
-                }
                 msleep(1);
                 spin_lock_irqsave(&chip->lock, flags);
-        }
+                reg = snd_cs4231_in(chip, CS4231_TEST_INIT);
+                reg &= CS4231_CALIB_IN_PROGRESS;
+        } while (reg && time_before(jiffies, timeout));
         spin_unlock_irqrestore(&chip->lock, flags);
+
+        if (reg)
+                snd_printk(KERN_ERR
+                           "mce_down - auto calibration time out (2)\n");
 }
 
 static void snd_cs4231_advance_dma(struct cs4231_dma_control *dma_cont,