From 859a288601a5dd6322c0153da7d2baf1dba64922 Mon Sep 17 00:00:00 2001
From: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Date: Tue, 17 Jan 2017 10:29:03 +0200
Subject: [PATCH 248/255] drm: bridge: dw-hdmi: Reject invalid product IDs

The DWC HDMI TX can be recognized by the two product identification
registers. If the registers don't read as expect the IP will be very
different than what the driver has been designed for, or will be
misconfigured in a way that makes it non-operational (invalid memory
address, incorrect clocks, ...). We should reject this situation with an
error.

While this isn't critical for proper operation with supported IPs at the
moment, the driver will soon gain automatic device-specific handling
based on runtime device identification. This change makes it easier to
implement that without having to default to a random guess in case the
device can't be identified.

While at it print a readable version number in the device identification
message instead of raw register values.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20170117082910.27023-14-laurent.pinchart+renesas@ideasonboard.com
(cherry picked from commit 0527e12e8264ae96b1fcc550b4a9e5940f4ffc30)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
---
 drivers/gpu/drm/bridge/dw-hdmi.c |   25 +++++++++++++++++++------
 drivers/gpu/drm/bridge/dw-hdmi.h |    8 ++++++++
 2 files changed, 27 insertions(+), 6 deletions(-)

--- a/drivers/gpu/drm/bridge/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/dw-hdmi.c
@@ -1832,6 +1832,9 @@ __dw_hdmi_probe(struct platform_device *
 	int irq;
 	int ret;
 	u32 val = 1;
+	u16 version;
+	u8 prod_id0;
+	u8 prod_id1;
 	u8 config0;
 	u8 config1;
 
@@ -1914,12 +1917,22 @@ __dw_hdmi_probe(struct platform_device *
 	}
 
 	/* Product and revision IDs */
-	dev_info(dev,
-		 "Detected HDMI controller 0x%x:0x%x:0x%x:0x%x\n",
-		 hdmi_readb(hdmi, HDMI_DESIGN_ID),
-		 hdmi_readb(hdmi, HDMI_REVISION_ID),
-		 hdmi_readb(hdmi, HDMI_PRODUCT_ID0),
-		 hdmi_readb(hdmi, HDMI_PRODUCT_ID1));
+	version = (hdmi_readb(hdmi, HDMI_DESIGN_ID) << 8)
+		| (hdmi_readb(hdmi, HDMI_REVISION_ID) << 0);
+	prod_id0 = hdmi_readb(hdmi, HDMI_PRODUCT_ID0);
+	prod_id1 = hdmi_readb(hdmi, HDMI_PRODUCT_ID1);
+
+	if (prod_id0 != HDMI_PRODUCT_ID0_HDMI_TX ||
+	    (prod_id1 & ~HDMI_PRODUCT_ID1_HDCP) != HDMI_PRODUCT_ID1_HDMI_TX) {
+		dev_err(dev, "Unsupported HDMI controller (%04x:%02x:%02x)\n",
+			version, prod_id0, prod_id1);
+		ret = -ENODEV;
+		goto err_iahb;
+	}
+
+	dev_info(dev, "Detected HDMI TX controller v%x.%03x %s HDCP\n",
+		 version >> 12, version & 0xfff,
+		 prod_id1 & HDMI_PRODUCT_ID1_HDCP ? "with" : "without");
 
 	initialize_hdmi_ih_mutes(hdmi);
 
--- a/drivers/gpu/drm/bridge/dw-hdmi.h
+++ b/drivers/gpu/drm/bridge/dw-hdmi.h
@@ -545,6 +545,14 @@
 #define HDMI_I2CM_FS_SCL_LCNT_0_ADDR            0x7E12
 
 enum {
+/* PRODUCT_ID0 field values */
+	HDMI_PRODUCT_ID0_HDMI_TX = 0xa0,
+
+/* PRODUCT_ID1 field values */
+	HDMI_PRODUCT_ID1_HDCP = 0xc0,
+	HDMI_PRODUCT_ID1_HDMI_RX = 0x02,
+	HDMI_PRODUCT_ID1_HDMI_TX = 0x01,
+
 /* CONFIG0_ID field values */
 	HDMI_CONFIG0_I2S = 0x10,