[PATCH v5 01/16] drm/i915: Fix sha_text population code

[PATCH v5 01/16] drm/i915: Fix sha_text population code

[Sean Paul]

From: Sean Paul <seanpaul@chromium.org>

This patch fixes a few bugs:

1- We weren't taking into account sha_leftovers when adding multiple
   ksvs to sha_text. As such, we were or'ing the end of ksv[j - 1] with
   the beginning of ksv[j]

2- In the sha_leftovers == 2 and sha_leftovers == 3 case, bstatus was
   being placed on the wrong half of sha_text, overlapping the leftover
   ksv value

3- In the sha_leftovers == 2 case, we need to manually terminate the
   byte stream with 0x80 since the hardware doesn't have enough room to
   add it after writing M0

The upside is that all of the HDCP supported HDMI repeaters I could
find on Amazon just strip HDCP anyways, so it turns out to be _really_
hard to hit any of these cases without an MST hub, which is not (yet)
supported. Oh, and the sha_leftovers == 1 case works perfectly!

Fixes: ee5e5e7a5e0f (drm/i915: Add HDCP framework + base implementation)
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ramalingam C <ramalingam.c@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v4.17+
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191203173638.94919-2-sean@poorly.run #v1
Link: https://patchwork.freedesktop.org/patch/msgid/20191212190230.188505-2-sean@poorly.run #v2
Link: https://patchwork.freedesktop.org/patch/msgid/20200117193103.156821-2-sean@poorly.run #v3
Link: https://patchwork.freedesktop.org/patch/msgid/20200218220242.107265-2-sean@poorly.run #v4

Changes in v2:
-None
Changes in v3:
-None
Changes in v4:
-Rebased on intel_de_write changes
Changes in v5:
-None
---
 drivers/gpu/drm/i915/display/intel_hdcp.c | 26 +++++++++++++++++------
 include/drm/drm_hdcp.h                    |  3 +++
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index ee0f27ea2810d..defa8654e7ac5 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -338,8 +338,10 @@ int intel_hdcp_validate_v_prime(struct intel_connector *connector,
 
 		/* Fill up the empty slots in sha_text and write it out */
 		sha_empty = sizeof(sha_text) - sha_leftovers;
-		for (j = 0; j < sha_empty; j++)
-			sha_text |= ksv[j] << ((sizeof(sha_text) - j - 1) * 8);
+		for (j = 0; j < sha_empty; j++) {
+			u8 off = ((sizeof(sha_text) - j - 1 - sha_leftovers) * 8);
+			sha_text |= ksv[j] << off;
+		}
 
 		ret = intel_write_sha_text(dev_priv, sha_text);
 		if (ret < 0)
@@ -437,7 +439,7 @@ int intel_hdcp_validate_v_prime(struct intel_connector *connector,
 		/* Write 32 bits of text */
 		intel_de_write(dev_priv, HDCP_REP_CTL,
 			       rep_ctl | HDCP_SHA1_TEXT_32);
-		sha_text |= bstatus[0] << 24 | bstatus[1] << 16;
+		sha_text |= bstatus[0] << 8 | bstatus[1];
 		ret = intel_write_sha_text(dev_priv, sha_text);
 		if (ret < 0)
 			return ret;
@@ -452,17 +454,29 @@ int intel_hdcp_validate_v_prime(struct intel_connector *connector,
 				return ret;
 			sha_idx += sizeof(sha_text);
 		}
+
+		/*
+		 * Terminate the SHA-1 stream by hand. For the other leftover
+		 * cases this is appended by the hardware.
+		 */
+		intel_de_write(dev_priv, HDCP_REP_CTL,
+			       rep_ctl | HDCP_SHA1_TEXT_32);
+		sha_text = DRM_HDCP_SHA1_TERMINATOR << 24;
+		ret = intel_write_sha_text(dev_priv, sha_text);
+		if (ret < 0)
+			return ret;
+		sha_idx += sizeof(sha_text);
 	} else if (sha_leftovers == 3) {
-		/* Write 32 bits of text */
+		/* Write 32 bits of text (filled from LSB) */
 		intel_de_write(dev_priv, HDCP_REP_CTL,
 			       rep_ctl | HDCP_SHA1_TEXT_32);
-		sha_text |= bstatus[0] << 24;
+		sha_text |= bstatus[0];
 		ret = intel_write_sha_text(dev_priv, sha_text);
 		if (ret < 0)
 			return ret;
 		sha_idx += sizeof(sha_text);
 
-		/* Write 8 bits of text, 24 bits of M0 */
+		/* Write 8 bits of text (filled from LSB), 24 bits of M0 */
 		intel_de_write(dev_priv, HDCP_REP_CTL,
 			       rep_ctl | HDCP_SHA1_TEXT_8);
 		ret = intel_write_sha_text(dev_priv, bstatus[1]);
diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h
index c6bab4986a658..fe58dbb46962a 100644
--- a/include/drm/drm_hdcp.h
+++ b/include/drm/drm_hdcp.h
@@ -29,6 +29,9 @@
 /* Slave address for the HDCP registers in the receiver */
 #define DRM_HDCP_DDC_ADDR			0x3A
 
+/* Value to use at the end of the SHA-1 bytestream used for repeaters */
+#define DRM_HDCP_SHA1_TERMINATOR		0x80
+
 /* HDCP register offsets for HDMI/DVI devices */
 #define DRM_HDCP_DDC_BKSV			0x00
 #define DRM_HDCP_DDC_RI_PRIME			0x08
-- 
Sean Paul, Software Engineer, Google / Chromium OS

[PATCH v5 02/16] drm/i915: Clear the repeater bit on HDCP disable

[Sean Paul]

From: Sean Paul <seanpaul@chromium.org>

On HDCP disable, clear the repeater bit. This ensures if we connect a
non-repeater sink after a repeater, the bit is in the state we expect.

Fixes: ee5e5e7a5e0f (drm/i915: Add HDCP framework + base implementation)
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ramalingam C <ramalingam.c@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v4.17+
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191212190230.188505-3-sean@poorly.run #v2
Link: https://patchwork.freedesktop.org/patch/msgid/20200117193103.156821-3-sean@poorly.run #v3
Link: https://patchwork.freedesktop.org/patch/msgid/20200218220242.107265-3-sean@poorly.run #v4

Changes in v2:
-Added to the set
Changes in v3:
-None
  I had previously agreed that clearing the rep_ctl bits on enable would
  also be a good idea. However when I committed that idea to code, it
  didn't look right. So let's rely on enables and disables being paired
  and everything outside of that will be considered a bug
Changes in v4:
-s/I915_(READ|WRITE)/intel_de_(read|write)/
Changes in v5:
-None
---
 drivers/gpu/drm/i915/display/intel_hdcp.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_hdcp.c b/drivers/gpu/drm/i915/display/intel_hdcp.c
index defa8654e7ac5..553f5ff617a15 100644
--- a/drivers/gpu/drm/i915/display/intel_hdcp.c
+++ b/drivers/gpu/drm/i915/display/intel_hdcp.c
@@ -797,6 +797,7 @@ static int _intel_hdcp_disable(struct intel_connector *connector)
 	struct intel_hdcp *hdcp = &connector->hdcp;
 	enum port port = intel_dig_port->base.port;
 	enum transcoder cpu_transcoder = hdcp->cpu_transcoder;
+	u32 repeater_ctl;
 	int ret;
 
 	drm_dbg_kms(&dev_priv->drm, "[%s:%d] HDCP is being disabled...\n",
@@ -812,6 +813,11 @@ static int _intel_hdcp_disable(struct intel_connector *connector)
 		return -ETIMEDOUT;
 	}
 
+	repeater_ctl = intel_hdcp_get_repeater_ctl(dev_priv, cpu_transcoder,
+						   port);
+	intel_de_write(dev_priv, HDCP_REP_CTL,
+		       intel_de_read(dev_priv, HDCP_REP_CTL) & ~repeater_ctl);
+
 	ret = hdcp->shim->toggle_signalling(intel_dig_port, false);
 	if (ret) {
 		drm_err(&dev_priv->drm, "Failed to disable HDCP signalling\n");
-- 
Sean Paul, Software Engineer, Google / Chromium OS