[PATCH AUTOSEL 6.6 13/17] drm/bridge: it6505: fix HDCP Bstatus check

[Sasha Levin <sashal@kernel.org>]

From: Hermes Wu <hermes.wu@ite.com.tw>

[ Upstream commit 0fd2ff47d8c207fa3173661de04bb9e8201c0ad2 ]

When HDCP is activated,
a DisplayPort source receiving CP_IRQ from the sink
shall check Bstatus from DPCD and process the corresponding value

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Hermes Wu <hermes.wu@ite.com.tw>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20241230-v7-upstream-v7-5-e0fdd4844703@ite.corp-partner.google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/bridge/ite-it6505.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index b7f70c8d14473..0eb831686a6ea 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -2309,14 +2309,20 @@ static int it6505_process_hpd_irq(struct it6505 *it6505)
 	DRM_DEV_DEBUG_DRIVER(dev, "dp_irq_vector = 0x%02x", dp_irq_vector);
 
 	if (dp_irq_vector & DP_CP_IRQ) {
-		it6505_set_bits(it6505, REG_HDCP_TRIGGER, HDCP_TRIGGER_CPIRQ,
-				HDCP_TRIGGER_CPIRQ);
-
 		bstatus = it6505_dpcd_read(it6505, DP_AUX_HDCP_BSTATUS);
 		if (bstatus < 0)
 			return bstatus;
 
 		DRM_DEV_DEBUG_DRIVER(dev, "Bstatus = 0x%02x", bstatus);
+
+		/*Check BSTATUS when recive CP_IRQ */
+		if (bstatus & DP_BSTATUS_R0_PRIME_READY &&
+		    it6505->hdcp_status == HDCP_AUTH_GOING)
+			it6505_set_bits(it6505, REG_HDCP_TRIGGER, HDCP_TRIGGER_CPIRQ,
+					HDCP_TRIGGER_CPIRQ);
+		else if (bstatus & (DP_BSTATUS_REAUTH_REQ | DP_BSTATUS_LINK_FAILURE) &&
+			 it6505->hdcp_status == HDCP_AUTH_DONE)
+			it6505_start_hdcp(it6505);
 	}
 
 	ret = drm_dp_dpcd_read_link_status(&it6505->aux, link_status);
-- 
2.39.5