ASoC: Intel: Common: Update dsp register poll implementation

Poll implementation is not quite accurate, especially for smaller
values of timeout or timeout values close to the actual timeout needed

Use jiffies to set the timeout value and time_before() to get the
accurate time. So update the dsp register poll implementation to
provide accurate timeout using jiffies.

Signed-off-by: Jayachandran B <jayachandran.b@intel.com>
Signed-off-by: Jeeja KP <jeeja.kp@intel.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/intel/common/sst-dsp.c

@@ -252,44 +252,44 @@ void sst_dsp_shim_update_bits_forced(struct sst_dsp *sst, u32 offset,
 EXPORT_SYMBOL_GPL(sst_dsp_shim_update_bits_forced);
 
 int sst_dsp_register_poll(struct sst_dsp *ctx, u32 offset, u32 mask,
-			 u32 target, u32 timeout, char *operation)
+			 u32 target, u32 time, char *operation)
 {
-	int time, ret;
 	u32 reg;
-	bool done = false;
+	unsigned long timeout;
+	int k = 0, s = 500;
 
 	/*
-	 * we will poll for couple of ms using mdelay, if not successful
-	 * then go to longer sleep using usleep_range
+	 * split the loop into sleeps of varying resolution. more accurately,
+	 * the range of wakeups are:
+	 * Phase 1(first 5ms): min sleep 0.5ms; max sleep 1ms.
+	 * Phase 2:( 5ms to 10ms) : min sleep 0.5ms; max sleep 10ms
+	 * (usleep_range (500, 1000) and usleep_range(5000, 10000) are
+	 * both possible in this phase depending on whether k > 10 or not).
+	 * Phase 3: (beyond 10 ms) min sleep 5ms; max sleep 10ms.
 	 */
 
-	/* check if set state successful */
-	for (time = 0; time < 5; time++) {
-		if ((sst_dsp_shim_read_unlocked(ctx, offset) & mask) == target) {
-			done = true;
-			break;
-		}
-		mdelay(1);
-	}
+	timeout = jiffies + msecs_to_jiffies(time);
+	while (((sst_dsp_shim_read_unlocked(ctx, offset) & mask) != target)
+		&& time_before(jiffies, timeout)) {
+		k++;
+		if (k > 10)
+			s = 5000;
 
-	if (done ==  false) {
-		/* sleeping in 10ms steps so adjust timeout value */
-		timeout /= 10;
-
-		for (time = 0; time < timeout; time++) {
-			if ((sst_dsp_shim_read_unlocked(ctx, offset) & mask) == target)
-				break;
-
-			usleep_range(5000, 10000);
-		}
+		usleep_range(s, 2*s);
 	}
 
 	reg = sst_dsp_shim_read_unlocked(ctx, offset);
-	dev_dbg(ctx->dev, "FW Poll Status: reg=%#x %s %s\n", reg, operation,
-			(time < timeout) ? "successful" : "timedout");
-	ret = time < timeout ? 0 : -ETIME;
 
-	return ret;
+	if ((reg & mask) == target) {
+		dev_dbg(ctx->dev, "FW Poll Status: reg=%#x %s successful\n",
+					reg, operation);
+
+		return 0;
+	}
+
+	dev_dbg(ctx->dev, "FW Poll Status: reg=%#x %s timedout\n",
+					reg, operation);
+	return -ETIME;
 }
 EXPORT_SYMBOL_GPL(sst_dsp_register_poll);