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Commit 41baafae authored by Ramalingam C's avatar Ramalingam C Committed by Rodrigo Vivi
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drm/i915: Read Vprime thrice incase of mismatch 



In case of V prime mismatch, DP HDCP spec mandates the re-read of
Vprime atleast twice.

This patch needed for DP HDCP1.4 CTS Test: 1B-05.

v2:
  Moved the V' validation into a function for retry. [Sean Paul]
v3:
  Removed Inline keyword and DRM_DEBUG_KMS are used [Sean Paul]

Signed-off-by: default avatarRamalingam C <ramalingam.c@intel.com>
Reviewed-by: default avatarSean Paul <seanpaul@chromium.org>
Signed-off-by: default avatarRodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1522663834-24482-3-git-send-email-ramalingam.c@intel.com
parent 4bfbec68

drivers/gpu/drm/i915/intel_hdcp.c

+70 −42
Original line number Diff line number Diff line
@@ -142,53 +142,17 @@ bool intel_hdcp_is_ksv_valid(u8 *ksv) 
	return true;

}



/* Implements Part 2 of the HDCP authorization procedure */

static

int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port,

			       const struct intel_hdcp_shim *shim)

int intel_hdcp_validate_v_prime(struct intel_digital_port *intel_dig_port,

				const struct intel_hdcp_shim *shim,

				u8 *ksv_fifo, u8 num_downstream, u8 *bstatus)

{

	struct drm_i915_private *dev_priv;

	u32 vprime, sha_text, sha_leftovers, rep_ctl;

	u8 bstatus[2], num_downstream, *ksv_fifo;

	int ret, i, j, sha_idx;



	dev_priv = intel_dig_port->base.base.dev->dev_private;



	ret = intel_hdcp_poll_ksv_fifo(intel_dig_port, shim);

	if (ret) {

		DRM_ERROR("KSV list failed to become ready (%d)\n", ret);

		return ret;

	}



	ret = shim->read_bstatus(intel_dig_port, bstatus);

	if (ret)

		return ret;



	if (DRM_HDCP_MAX_DEVICE_EXCEEDED(bstatus[0]) ||

	    DRM_HDCP_MAX_CASCADE_EXCEEDED(bstatus[1])) {

		DRM_ERROR("Max Topology Limit Exceeded\n");

		return -EPERM;

	}



	/*

	 * When repeater reports 0 device count, HDCP1.4 spec allows disabling

	 * the HDCP encryption. That implies that repeater can't have its own

	 * display. As there is no consumption of encrypted content in the

	 * repeater with 0 downstream devices, we are failing the

	 * authentication.

	 */

	num_downstream = DRM_HDCP_NUM_DOWNSTREAM(bstatus[0]);

	if (num_downstream == 0)

		return -EINVAL;



	ksv_fifo = kzalloc(num_downstream * DRM_HDCP_KSV_LEN, GFP_KERNEL);

	if (!ksv_fifo)

		return -ENOMEM;



	ret = shim->read_ksv_fifo(intel_dig_port, num_downstream, ksv_fifo);

	if (ret)

		return ret;



	/* Process V' values from the receiver */

	for (i = 0; i < DRM_HDCP_V_PRIME_NUM_PARTS; i++) {

		ret = shim->read_v_prime_part(intel_dig_port, i, &vprime);
@@ -353,7 +317,8 @@ int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port, 
			return ret;

		sha_idx += sizeof(sha_text);

	} else {

		DRM_ERROR("Invalid number of leftovers %d\n", sha_leftovers);

		DRM_DEBUG_KMS("Invalid number of leftovers %d\n",

			      sha_leftovers);

		return -EINVAL;

	}
@@ -381,14 +346,77 @@ int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port, 
	if (intel_wait_for_register(dev_priv, HDCP_REP_CTL,

				    HDCP_SHA1_COMPLETE,

				    HDCP_SHA1_COMPLETE, 1)) {

		DRM_ERROR("Timed out waiting for SHA1 complete\n");

		DRM_DEBUG_KMS("Timed out waiting for SHA1 complete\n");

		return -ETIMEDOUT;

	}

	if (!(I915_READ(HDCP_REP_CTL) & HDCP_SHA1_V_MATCH)) {

		DRM_ERROR("SHA-1 mismatch, HDCP failed\n");

		DRM_DEBUG_KMS("SHA-1 mismatch, HDCP failed\n");

		return -ENXIO;

	}



	return 0;

}



/* Implements Part 2 of the HDCP authorization procedure */

static

int intel_hdcp_auth_downstream(struct intel_digital_port *intel_dig_port,

			       const struct intel_hdcp_shim *shim)

{

	u8 bstatus[2], num_downstream, *ksv_fifo;

	int ret, i, tries = 3;



	ret = intel_hdcp_poll_ksv_fifo(intel_dig_port, shim);

	if (ret) {

		DRM_ERROR("KSV list failed to become ready (%d)\n", ret);

		return ret;

	}



	ret = shim->read_bstatus(intel_dig_port, bstatus);

	if (ret)

		return ret;



	if (DRM_HDCP_MAX_DEVICE_EXCEEDED(bstatus[0]) ||

	    DRM_HDCP_MAX_CASCADE_EXCEEDED(bstatus[1])) {

		DRM_ERROR("Max Topology Limit Exceeded\n");

		return -EPERM;

	}



	/*

	 * When repeater reports 0 device count, HDCP1.4 spec allows disabling

	 * the HDCP encryption. That implies that repeater can't have its own

	 * display. As there is no consumption of encrypted content in the

	 * repeater with 0 downstream devices, we are failing the

	 * authentication.

	 */

	num_downstream = DRM_HDCP_NUM_DOWNSTREAM(bstatus[0]);

	if (num_downstream == 0)

		return -EINVAL;



	ksv_fifo = kzalloc(num_downstream * DRM_HDCP_KSV_LEN, GFP_KERNEL);

	if (!ksv_fifo)

		return -ENOMEM;



	ret = shim->read_ksv_fifo(intel_dig_port, num_downstream, ksv_fifo);

	if (ret)

		return ret;



	/*

	 * When V prime mismatches, DP Spec mandates re-read of

	 * V prime atleast twice.

	 */

	for (i = 0; i < tries; i++) {

		ret = intel_hdcp_validate_v_prime(intel_dig_port, shim,

						  ksv_fifo, num_downstream,

						  bstatus);

		if (!ret)

			break;

	}



	if (i == tries) {

		DRM_ERROR("V Prime validation failed.(%d)\n", ret);

		return ret;

	}



	DRM_DEBUG_KMS("HDCP is enabled (%d downstream devices)\n",

		      num_downstream);

	return 0;