Re: [PATCH v2 2/4] drm/i915: Read Vprime thrice incase of mismatch

On Thursday 29 March 2018 08:08 PM, Sean Paul wrote:

On Thu, Mar 29, 2018 at 07:39:06PM +0530, Ramalingam C wrote:

...

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]

Signed-off-by: Ramalingam C ramalingam.c@intel.com

drivers/gpu/drm/i915/intel_hdcp.c | 113 +++++++++++++++++++++++--------------- 1 file changed, 70 insertions(+), 43 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c index 96b9025dc759..f77d956b2b18 100644 --- a/drivers/gpu/drm/i915/intel_hdcp.c +++ b/drivers/gpu/drm/i915/intel_hdcp.c @@ -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)
  

+static inline

Why inline?

Its a mistake. Will correct it. thanks

...

+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 +317,7 @@ 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("Invalid number of leftovers %d\n", sha_leftovers);
  

  return -EINVAL; }

@@ -381,14 +345,77 @@ 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("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("SHA-1 mismatch, HDCP failed\n");
  

I think the DEBUG should be DEBUG_KMS, consistent with the rest of the file?

Will make it uniform

--Ram

...

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;

-- 2.7.4