ASoC: SOF: Intel: CNL: add support for sending compact IPC

For compact IPCs, we will send the IPC header/command via the HIPCIDR
register and the first 32bit payload via the HIPCIDD register, no
mailbox will be used.
Signed-off-by: Keyon Jie <yang.jie@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20191025224122.7718-19-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/intel/cnl.c

@@ -17,6 +17,7 @@
 
 #include "../ops.h"
 #include "hda.h"
+#include "hda-ipc.h"
 
 static const struct snd_sof_debugfs_map cnl_dsp_debugfs[] = {
 	{"hda", HDA_DSP_HDA_BAR, 0, 0x4000, SOF_DEBUGFS_ACCESS_ALWAYS},
@@ -150,14 +151,45 @@ static void cnl_ipc_dsp_done(struct snd_sof_dev *sdev)
 				CNL_DSP_REG_HIPCCTL_DONE);
 }
 
+static bool cnl_compact_ipc_compress(struct snd_sof_ipc_msg *msg,
+				     u32 *dr, u32 *dd)
+{
+	struct sof_ipc_pm_gate *pm_gate;
+
+	if (msg->header == (SOF_IPC_GLB_PM_MSG | SOF_IPC_PM_GATE)) {
+		pm_gate = msg->msg_data;
+
+		/* send the compact message via the primary register */
+		*dr = HDA_IPC_MSG_COMPACT | HDA_IPC_PM_GATE;
+
+		/* send payload via the extended data register */
+		*dd = pm_gate->flags;
+
+		return true;
+	}
+
+	return false;
+}
+
 static int cnl_ipc_send_msg(struct snd_sof_dev *sdev,
 			    struct snd_sof_ipc_msg *msg)
 {
-	/* send the message */
-	sof_mailbox_write(sdev, sdev->host_box.offset, msg->msg_data,
-			  msg->msg_size);
-	snd_sof_dsp_write(sdev, HDA_DSP_BAR, CNL_DSP_REG_HIPCIDR,
-			  CNL_DSP_REG_HIPCIDR_BUSY);
+	u32 dr = 0;
+	u32 dd = 0;
+
+	if (cnl_compact_ipc_compress(msg, &dr, &dd)) {
+		/* send the message via IPC registers */
+		snd_sof_dsp_write(sdev, HDA_DSP_BAR, CNL_DSP_REG_HIPCIDD,
+				  dd);
+		snd_sof_dsp_write(sdev, HDA_DSP_BAR, CNL_DSP_REG_HIPCIDR,
+				  CNL_DSP_REG_HIPCIDR_BUSY | dr);
+	} else {
+		/* send the message via mailbox */
+		sof_mailbox_write(sdev, sdev->host_box.offset, msg->msg_data,
+				  msg->msg_size);
+		snd_sof_dsp_write(sdev, HDA_DSP_BAR, CNL_DSP_REG_HIPCIDR,
+				  CNL_DSP_REG_HIPCIDR_BUSY);
+	}
 
 	return 0;
 }

sound/soc/sof/intel/hda.h

@@ -312,6 +312,7 @@
 #define CNL_DSP_REG_HIPCTDD		(CNL_DSP_IPC_BASE + 0x08)
 #define CNL_DSP_REG_HIPCIDR		(CNL_DSP_IPC_BASE + 0x10)
 #define CNL_DSP_REG_HIPCIDA		(CNL_DSP_IPC_BASE + 0x14)
+#define CNL_DSP_REG_HIPCIDD		(CNL_DSP_IPC_BASE + 0x18)
 #define CNL_DSP_REG_HIPCCTL		(CNL_DSP_IPC_BASE + 0x28)
 
 /*  HIPCI */