drm/bridge: it6505: fix HDCP CTS KSV list read with UNIGRAF DPR-100.

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.

Reviewed-by: Dmitry Baryshkov <[email protected]>
Signed-off-by: Hermes Wu <[email protected]>
Reviewed-by: AngeloGioacchino Del Regno <[email protected]>
Signed-off-by: Dmitry Baryshkov <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/20241230-v7-upstream-v7-7-e0fdd4844703@ite.corp-partner.google.com

Author: Hermes Wu

drivers/gpu/drm/bridge/ite-it6505.c

@@ -1189,6 +1189,37 @@ 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;
@@ -1970,7 +2001,7 @@ 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));
@@ -1995,18 +2026,11 @@ 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];