[PATCH] ASoC: SOF: Intel: hda: unsolicited RIRB response

[Brent Lu <brent.lu@intel.com>]

The loop implementation could not solve the unsolicited response
issue because the RIRBSTS is cleared after leaving the
snd_hdac_bus_update_rirb() function. So the next loop will fail the
status test against the RIRB_INT_MASK and skip all the RIRB handling
stuff. On the other hand, there alwasy could be unsolicited responses
in the last loop regardless the number of loops.

Clear the RIRB interrupt before handling it so unsolicited response
could trigger another RIRB interrupt to handle it later.

Signed-off-by: Brent Lu <brent.lu@intel.com>
---
 sound/soc/sof/intel/hda-stream.c | 48 +++++++++++++++++-----------------------
 1 file changed, 20 insertions(+), 28 deletions(-)

diff --git a/sound/soc/sof/intel/hda-stream.c b/sound/soc/sof/intel/hda-stream.c
index 7f65dcc..d21ac42 100644
--- a/sound/soc/sof/intel/hda-stream.c
+++ b/sound/soc/sof/intel/hda-stream.c
@@ -589,11 +589,10 @@ hda_dsp_set_bytes_transferred(struct hdac_stream *hstream, u64 buffer_size)
 	hstream->curr_pos += num_bytes;
 }
 
-static bool hda_dsp_stream_check(struct hdac_bus *bus, u32 status)
+static void hda_dsp_stream_check(struct hdac_bus *bus, u32 status)
 {
 	struct sof_intel_hda_dev *sof_hda = bus_to_sof_hda(bus);
 	struct hdac_stream *s;
-	bool active = false;
 	u32 sd_status;
 
 	list_for_each_entry(s, &bus->stream_list, list) {
@@ -605,7 +604,6 @@ static bool hda_dsp_stream_check(struct hdac_bus *bus, u32 status)
 
 			snd_hdac_stream_writeb(s, SD_STS, sd_status);
 
-			active = true;
 			if ((!s->substream && !s->cstream) ||
 			    !s->running ||
 			    (sd_status & SOF_HDA_CL_DMA_SD_INT_COMPLETE) == 0)
@@ -621,8 +619,6 @@ static bool hda_dsp_stream_check(struct hdac_bus *bus, u32 status)
 			}
 		}
 	}
-
-	return active;
 }
 
 irqreturn_t hda_dsp_stream_threaded_handler(int irq, void *context)
@@ -632,37 +628,33 @@ irqreturn_t hda_dsp_stream_threaded_handler(int irq, void *context)
 #if IS_ENABLED(CONFIG_SND_SOC_SOF_HDA)
 	u32 rirb_status;
 #endif
-	bool active;
 	u32 status;
-	int i;
 
-	/*
-	 * Loop 10 times to handle missed interrupts caused by
-	 * unsolicited responses from the codec
-	 */
-	for (i = 0, active = true; i < 10 && active; i++) {
-		spin_lock_irq(&bus->reg_lock);
+	spin_lock_irq(&bus->reg_lock);
 
-		status = snd_hdac_chip_readl(bus, INTSTS);
+	status = snd_hdac_chip_readl(bus, INTSTS);
 
-		/* check streams */
-		active = hda_dsp_stream_check(bus, status);
+	/* check streams */
+	hda_dsp_stream_check(bus, status);
 
-		/* check and clear RIRB interrupt */
+	/* check and clear RIRB interrupt */
 #if IS_ENABLED(CONFIG_SND_SOC_SOF_HDA)
-		if (status & AZX_INT_CTRL_EN) {
-			rirb_status = snd_hdac_chip_readb(bus, RIRBSTS);
-			if (rirb_status & RIRB_INT_MASK) {
-				active = true;
-				if (rirb_status & RIRB_INT_RESPONSE)
-					snd_hdac_bus_update_rirb(bus);
-				snd_hdac_chip_writeb(bus, RIRBSTS,
-						     RIRB_INT_MASK);
-			}
+	if (status & AZX_INT_CTRL_EN) {
+		rirb_status = snd_hdac_chip_readb(bus, RIRBSTS);
+		if (rirb_status & RIRB_INT_MASK) {
+			/*
+			 * clear current interrupt before reading RIRBWP
+			 * so unsolicited response could trigger another
+			 * interrupt
+			 */
+			snd_hdac_chip_writeb(bus, RIRBSTS, RIRB_INT_MASK);
+
+			if (rirb_status & RIRB_INT_RESPONSE)
+				snd_hdac_bus_update_rirb(bus);
 		}
-#endif
-		spin_unlock_irq(&bus->reg_lock);
 	}
+#endif
+	spin_unlock_irq(&bus->reg_lock);
 
 	return IRQ_HANDLED;
 }
-- 
2.7.4