[PATCH 6/8] soundwire: intel: add helpers for link power down and shim wake

[Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>]

These routines are required for power management

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
 drivers/soundwire/intel.c | 53 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index d5533564195a..eafa2016c76d 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -362,6 +362,59 @@ static int intel_shim_init(struct sdw_intel *sdw)
 	return ret;
 }
 
+static void intel_shim_wake(struct sdw_intel *sdw, bool wake_enable)
+{
+	void __iomem *shim = sdw->link_res->shim;
+	unsigned int link_id = sdw->instance;
+	u16 wake_en, wake_sts;
+
+	if (wake_enable) {
+		/* Enable the wakeup */
+		intel_writew(shim, SDW_SHIM_WAKEEN,
+			     (SDW_SHIM_WAKEEN_ENABLE << link_id));
+	} else {
+		/* Disable the wake up interrupt */
+		wake_en = intel_readw(shim, SDW_SHIM_WAKEEN);
+		wake_en &= ~(SDW_SHIM_WAKEEN_ENABLE << link_id);
+		intel_writew(shim, SDW_SHIM_WAKEEN, wake_en);
+
+		/* Clear wake status */
+		wake_sts = intel_readw(shim, SDW_SHIM_WAKESTS);
+		wake_sts |= (SDW_SHIM_WAKEEN_ENABLE << link_id);
+		intel_writew(shim, SDW_SHIM_WAKESTS_STATUS, wake_sts);
+	}
+}
+
+static int intel_link_power_down(struct sdw_intel *sdw)
+{
+	int link_control, spa_mask, cpa_mask, ret;
+	unsigned int link_id = sdw->instance;
+	void __iomem *shim = sdw->link_res->shim;
+	u16 ioctl;
+
+	/* Glue logic */
+	ioctl = intel_readw(shim, SDW_SHIM_IOCTL(link_id));
+	ioctl |= SDW_SHIM_IOCTL_BKE;
+	ioctl |= SDW_SHIM_IOCTL_COE;
+	intel_writew(shim, SDW_SHIM_IOCTL(link_id), ioctl);
+
+	ioctl &= ~(SDW_SHIM_IOCTL_MIF);
+	intel_writew(shim, SDW_SHIM_IOCTL(link_id), ioctl);
+
+	/* Link power down sequence */
+	link_control = intel_readl(shim, SDW_SHIM_LCTL);
+	spa_mask = ~(SDW_SHIM_LCTL_SPA << link_id);
+	cpa_mask = (SDW_SHIM_LCTL_CPA << link_id);
+	link_control &=  spa_mask;
+
+	ret = intel_clear_bit(shim, SDW_SHIM_LCTL, link_control, cpa_mask);
+	if (ret < 0)
+		return ret;
+
+	sdw->cdns.link_up = false;
+	return 0;
+}
+
 /*
  * PDI routines
  */
-- 
2.20.1