linux-kernel - [PATCH v6 07/10] drm/bridge: it6505: fix HDCP CTS KSV list read with UNIGRAF DPR-100.

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Message-Id: <20241016-upstream-v6-v6-7-4d93a0c46de1@ite.com.tw>
Date: Wed, 16 Oct 2024 15:54:19 +0800
From: Hermes Wu via B4 Relay <devnull+Hermes.wu.ite.com.tw@...nel.org>
To: 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>, 
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, 
 Pin-yen Lin <treapking@...omium.org>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org, 
 Kenneth Hung <Kenneth.hung@....com.tw>, Pet Weng <Pet.Weng@....com.tw>, 
 Hermes Wu <Hermes.wu@....com.tw>
Subject: [PATCH v6 07/10] drm/bridge: it6505: fix HDCP CTS KSV list read
 with UNIGRAF DPR-100.

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

When running the HDCP CTS test with UNIGRAF DPR-100.
KSV list must be read from DP_AUX_HDCP_KSV_FIFO in an AUX request,
and can not separate with multiple read requests.

The AUX operation command "CMD_AUX_GET_KSV_LIST" reads the KSV list
with AUX FIFO and is able to read DP_AUX_HDCP_KSV_FIFO in an AUX request.

Add it6505_get_ksvlist() which uses CMD_AUX_GET_KSV_LIST operation
to read the KSV list.

Signed-off-by: Hermes Wu <Hermes.wu@....com.tw>
---
 drivers/gpu/drm/bridge/ite-it6505.c | 48 +++++++++++++++++++++++++++----------
 1 file changed, 36 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 85626b49a048a1178676ed616130a522ca314152..40fb47f4954331d63681066fb3af19f0f57bb929 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -1188,6 +1188,37 @@ 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)
+{
+	struct device *dev = it6505->dev;
+	enum aux_cmd_reply reply;
+	int request_size, ret;
+	int i = 0;
+
+	do {
+		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;
+	} while (i < len);
+
+	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 +2000,7 @@ 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 +2025,11 @@ 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