[PATCH 7/8] soundwire: intel: add wake interrupt support

[Pierre-Louis Bossart]

From: Rander Wang <rander.wang at intel.com>

When system is suspended in clock stop mode on intel platforms, both
master and slave are in clock stop mode and soundwire bus is taken
over by a glue hardware. The bus message for jack event is processed
by this glue hardware, which will trigger an interrupt to resume audio
pci device. Then audio pci driver will resume soundwire master and slave,
transfer bus ownership to master, finally slave will report jack event
to master and codec driver is triggered to check jack status.

Signed-off-by: Rander Wang <rander.wang at intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
---
 drivers/soundwire/intel.c      | 45 ++++++++++++++++++++++++++++++++++
 drivers/soundwire/intel_init.c | 12 +++++++++
 2 files changed, 57 insertions(+)

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index eafa2016c76d..4cc6c857dd09 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -1255,6 +1255,50 @@ static int intel_master_remove(struct sdw_master_device *md)
 	return 0;
 }
 
+static int intel_master_process_wakeen_event(struct sdw_master_device *md)
+{
+	struct sdw_intel *sdw;
+	struct sdw_slave *slave;
+	struct sdw_bus *bus;
+	void __iomem *shim;
+	u16 wake_sts;
+
+	sdw = md->pdata;
+
+	if (sdw->cdns.bus.prop.hw_disabled) {
+		dev_info(&md->dev,
+			 "SoundWire master %d is disabled, ignoring\n",
+			 sdw->cdns.bus.link_id);
+		return 0;
+	}
+
+	shim = sdw->link_res->shim;
+	wake_sts = intel_readw(shim, SDW_SHIM_WAKESTS);
+
+	if (!(wake_sts & BIT(sdw->instance)))
+		return 0;
+
+	/* disable WAKEEN interrupt ASAP to prevent interrupt flood */
+	intel_shim_wake(sdw, false);
+
+	bus = &sdw->cdns.bus;
+
+	/*
+	 * wake up master and slave so that slave can notify master
+	 * the wakeen event and let codec driver check codec status
+	 */
+	list_for_each_entry(slave, &bus->slaves, node) {
+		if (slave->prop.wake_capable) {
+			if (slave->status != SDW_SLAVE_ATTACHED &&
+			    slave->status != SDW_SLAVE_ALERT)
+				continue;
+
+			pm_request_resume(&slave->dev);
+		}
+	}
+
+	return 0;
+}
 
 static struct sdw_master_driver intel_sdw_driver = {
 	.driver = {
@@ -1265,6 +1309,7 @@ static struct sdw_master_driver intel_sdw_driver = {
 	.probe = intel_master_probe,
 	.startup = intel_master_startup,
 	.remove = intel_master_remove,
+	.process_wake_event = intel_master_process_wakeen_event,
 };
 module_sdw_master_driver(intel_sdw_driver);
 
diff --git a/drivers/soundwire/intel_init.c b/drivers/soundwire/intel_init.c
index 954b21b4712d..91ec91127f2a 100644
--- a/drivers/soundwire/intel_init.c
+++ b/drivers/soundwire/intel_init.c
@@ -413,5 +413,17 @@ void sdw_intel_exit(struct sdw_intel_ctx *ctx)
 }
 EXPORT_SYMBOL_NS(sdw_intel_exit, SOUNDWIRE_INTEL_INIT);
 
+void sdw_intel_process_wakeen_event(struct sdw_intel_ctx *ctx)
+{
+	struct sdw_intel_link_res *link;
+
+	if (!ctx->links)
+		return;
+
+	list_for_each_entry(link, &ctx->link_list, list)
+		sdw_master_device_process_wake_event(link->md);
+}
+EXPORT_SYMBOL_NS(sdw_intel_process_wakeen_event, SOUNDWIRE_INTEL_INIT);
+
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_DESCRIPTION("Intel Soundwire Init Library");
-- 
2.20.1