linux-kernel - [PATCH v4 08/11] drm/bridge: it6505: fix HDCP KSV list did not read correctly.

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Message-ID: <20240926075018.22328-4-Hermes.Wu@ite.com.tw>
Date: Thu, 26 Sep 2024 15:50:17 +0800
From: Hermes Wu <Hermes.Wu@....com.tw>
To: hermes wu <Hermes.wu@....com.tw>
CC: Kenneth Hung <Kenneth.hung@....com.tw>,
        Andrzej Hajda
	<andrzej.hajda@...el.com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Robert
 Foss <rfoss@...nel.org>,
        Laurent Pinchart
	<Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej
 Skrabec <jernej.skrabec@...il.com>,
        Maarten Lankhorst
	<maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        Hermes Wu <hermes.wu@....com.tw>,
        AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
        Allen
 Chen <allen.chen@....com.tw>,
        "open list:DRM DRIVERS"
	<dri-devel@...ts.freedesktop.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: [PATCH v4 08/11] drm/bridge: it6505: fix HDCP KSV list did not read correctly.

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

When running the HDCP CTS test on UNIGRAF DPR-100.
KSV list must be read from DPCD with 5 byte boundary.

The original aux operation using AUX_NATIVE_READ can not read back the
KSV list correctly.
Change to CMD_AUX_GET_KSV_LIST operaction.


Fixes: b5c84a9edcd4 ("drm/bridge: add it6505 driver")
Signed-off-by: Hermes Wu <Hermes.wu@....com.tw>
---
 drivers/gpu/drm/bridge/ite-it6505.c | 46 +++++++++++++++++++++--------
 1 file changed, 34 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 82986f28f653..143d58ed1b0e 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -1188,6 +1188,35 @@ static int it6505_get_edid_block(void *data, u8 *buf, unsigned int block,
 	return 0;
 }
 
+static int it6505_get_ksvlist(struct it6505 *it6505, u8 *buf, size_t len)
+{
+	int i, request_size, ret;
+	struct device *dev = it6505->dev;
+	enum aux_cmd_reply reply;
+
+	for (i = 0; i < len; ) {
+		request_size = min_t(int, (int)len - i, 15);
+
+		ret = it6505_aux_do_transfer(it6505, CMD_AUX_GET_KSV_LIST,
+					     DP_AUX_HDCP_KSV_FIFO,
+					     buf + i, request_size, &reply);
+
+		DRM_DEV_DEBUG_DRIVER(dev, "request_size = %d, ret =%d", request_size, ret);
+		if (ret < 0)
+			return ret;
+
+		i += request_size;
+	}
+
+	DRM_DEV_DEBUG_DRIVER(dev, "ksv read cnt = %d down_stream_cnt=%d ", i, i / 5);
+
+	for (i = 0 ; i < len; i += 5)
+		DRM_DEV_DEBUG_DRIVER(dev, "ksv[%d] = %02X%02X%02X%02X%02X",
+				     i / 5, buf[i], buf[i + 1], buf[i + 2], buf[i + 3], buf[i + 4]);
+
+	return len;
+}
+
 static void it6505_variable_config(struct it6505 *it6505)
 {
 	it6505->link_rate_bw_code = HBR;
@@ -1969,7 +1998,7 @@ static int it6505_setup_sha1_input(struct it6505 *it6505, u8 *sha1_input)
 {
 	struct device *dev = it6505->dev;
 	u8 binfo[2];
-	int down_stream_count, i, err, msg_count = 0;
+	int down_stream_count, err, msg_count = 0;
 
 	err = it6505_get_dpcd(it6505, DP_AUX_HDCP_BINFO, binfo,
 			      ARRAY_SIZE(binfo));
@@ -1994,18 +2023,11 @@ static int it6505_setup_sha1_input(struct it6505 *it6505, u8 *sha1_input)
 			down_stream_count);
 		return 0;
 	}
+	err =  it6505_get_ksvlist(it6505, sha1_input, down_stream_count * 5);
+	if (err < 0)
+		return err;
 
-	for (i = 0; i < down_stream_count; i++) {
-		err = it6505_get_dpcd(it6505, DP_AUX_HDCP_KSV_FIFO +
-				      (i % 3) * DRM_HDCP_KSV_LEN,
-				      sha1_input + msg_count,
-				      DRM_HDCP_KSV_LEN);
-
-		if (err < 0)
-			return err;
-
-		msg_count += 5;
-	}
+	msg_count += down_stream_count * 5;
 
 	it6505->hdcp_down_stream_count = down_stream_count;
 	sha1_input[msg_count++] = binfo[0];
-- 
2.34.1