From 0ebf131d6c0a333f4abf914c5333a0fc6871062c Mon Sep 17 00:00:00 2001
From: Manasi Navare <manasi.d.navare@intel.com>
Date: Wed, 1 Jul 2020 15:10:51 -0700
Subject: drm/i915/dp: Helper for checking DDI_BUF_CTL Idle status
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Git-commit: 5a2ad99bcedf0ebbfb29e5d7a9764aae301ac64b
Patch-mainline: v5.9-rc1
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322

Modify the helper to add a fixed delay or poll with timeout
based on platform specification to check for either Idle bit
set (DDI_BUF_CTL is idle for disable case)

v2:
* Use 2 separate functions or idle and active (Ville)
v3:
* Change the timeout to 16usecs (Ville)
v4:
* Change the timeout 8, follow spec (Ville)

Cc: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Reviewed-by: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200701221052.8946-1-manasi.d.navare@intel.com
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/i915/display/intel_ddi.c | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 583170e73881..2120d6da3fcc 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -1184,16 +1184,15 @@ static void intel_prepare_hdmi_ddi_buffers(struct intel_encoder *encoder,
 static void intel_wait_ddi_buf_idle(struct drm_i915_private *dev_priv,
 				    enum port port)
 {
-	i915_reg_t reg = DDI_BUF_CTL(port);
-	int i;
-
-	for (i = 0; i < 16; i++) {
-		udelay(1);
-		if (intel_de_read(dev_priv, reg) & DDI_BUF_IS_IDLE)
-			return;
+	if (IS_BROXTON(dev_priv)) {
+		udelay(16);
+		return;
 	}
-	drm_err(&dev_priv->drm, "Timeout waiting for DDI BUF %c idle bit\n",
-		port_name(port));
+
+	if (wait_for_us((intel_de_read(dev_priv, DDI_BUF_CTL(port)) &
+			 DDI_BUF_IS_IDLE), 8))
+		drm_err(&dev_priv->drm, "Timeout waiting for DDI BUF %c to get idle\n",
+			port_name(port));
 }
 
 static u32 hsw_pll_to_ddi_pll_sel(const struct intel_shared_dpll *pll)
-- 
2.29.2