Sean,

We might want to check the panel's HDCP capability? Agreed that majority of HDMI/DP panel's supports it, but there is a possibility that we might avoid authentication on non-hdcp panels.

As per HDCP specification, check for valid bksv will serve the purpose.


On Thursday 30 November 2017 08:39 AM, Sean Paul wrote:
This patch adds HDCP support for HDMI connectors by implementing
the intel_hdcp_shim.

Nothing too special, just a bunch of DDC reads/writes.

Signed-off-by: Sean Paul <seanp...@chromium.org>
---
  drivers/gpu/drm/i915/i915_reg.h   |   1 +
  drivers/gpu/drm/i915/intel_ddi.c  |  50 ++++++++
  drivers/gpu/drm/i915/intel_hdmi.c | 253 ++++++++++++++++++++++++++++++++++++++
  3 files changed, 304 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 78370877fea3..061c52a5d7d7 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -8400,6 +8400,7 @@ enum skl_power_gate {
  #define  TRANS_DDI_EDP_INPUT_A_ONOFF  (4<<12)
  #define  TRANS_DDI_EDP_INPUT_B_ONOFF  (5<<12)
  #define  TRANS_DDI_EDP_INPUT_C_ONOFF  (6<<12)
+#define  TRANS_DDI_HDCP_SIGNALLING     (1<<9)
  #define  TRANS_DDI_DP_VC_PAYLOAD_ALLOC        (1<<8)
  #define  TRANS_DDI_HDMI_SCRAMBLER_CTS_ENABLE (1<<7)
  #define  TRANS_DDI_HDMI_SCRAMBLER_RESET_FREQ (1<<6)
diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 0e69337f410d..0324b09ecf76 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1650,6 +1650,56 @@ void intel_ddi_disable_transcoder_func(struct 
drm_i915_private *dev_priv,
        I915_WRITE(reg, val);
  }
+int intel_ddi_disable_hdcp_signalling(struct intel_encoder *intel_encoder)
+{
+       struct drm_device *dev = intel_encoder->base.dev;
+       struct drm_i915_private *dev_priv = to_i915(dev);
+       enum pipe pipe = 0;
+       int ret = 0;
+       uint32_t tmp;
+
+       if (!intel_display_power_get_if_enabled(dev_priv,
+                                               intel_encoder->power_domain))
+               return -ENXIO;
+
+       if (!intel_encoder->get_hw_state(intel_encoder, &pipe)) {
+               ret = -EIO;
+               goto out;
+       }
+
+       tmp = I915_READ(TRANS_DDI_FUNC_CTL(pipe));
+       tmp &= ~TRANS_DDI_HDCP_SIGNALLING;
+       I915_WRITE(TRANS_DDI_FUNC_CTL(pipe), tmp);
+out:
+       intel_display_power_put(dev_priv, intel_encoder->power_domain);
+       return ret;
+}
+
+int intel_ddi_enable_hdcp_signalling(struct intel_encoder *intel_encoder)
+{
+       struct drm_device *dev = intel_encoder->base.dev;
+       struct drm_i915_private *dev_priv = to_i915(dev);
+       enum pipe pipe = 0;
+       int ret = 0;
+       uint32_t tmp;
+
+       if (!intel_display_power_get_if_enabled(dev_priv,
+                                               intel_encoder->power_domain))
+               return -ENXIO;
+
+       if (!intel_encoder->get_hw_state(intel_encoder, &pipe)) {
+               ret = -EIO;
+               goto out;
+       }
+
+       tmp = I915_READ(TRANS_DDI_FUNC_CTL(pipe));
+       tmp |= TRANS_DDI_HDCP_SIGNALLING;
+       I915_WRITE(TRANS_DDI_FUNC_CTL(pipe), tmp);
+out:
+       intel_display_power_put(dev_priv, intel_encoder->power_domain);
+       return ret;
+}
+
  bool intel_ddi_connector_get_hw_state(struct intel_connector *intel_connector)
  {
        struct drm_device *dev = intel_connector->base.dev;
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c 
b/drivers/gpu/drm/i915/intel_hdmi.c
index 59247a49a077..563168897dd9 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -34,6 +34,7 @@
  #include <drm/drm_atomic_helper.h>
  #include <drm/drm_crtc.h>
  #include <drm/drm_edid.h>
+#include <drm/drm_hdcp.h>
  #include <drm/drm_scdc_helper.h>
  #include "intel_drv.h"
  #include <drm/i915_drm.h>
@@ -875,6 +876,252 @@ void intel_dp_dual_mode_set_tmds_output(struct intel_hdmi 
*hdmi, bool enable)
                                         adapter, enable);
  }
+static int intel_hdmi_hdcp_read(struct intel_digital_port *intel_dig_port,
+                               unsigned int offset, void *buffer, size_t size)
+{
+       struct intel_hdmi *hdmi = &intel_dig_port->hdmi;
+       struct drm_i915_private *dev_priv =
+               intel_dig_port->base.base.dev->dev_private;
+       struct i2c_adapter *adapter = intel_gmbus_get_adapter(dev_priv,
+                                                             hdmi->ddc_bus);
+       int ret;
+       u8 start = offset & 0xff;
+       struct i2c_msg msgs[] = {
+               {
+                       .addr = DRM_HDCP_DDC_ADDR,
+                       .flags = 0,
+                       .len = 1,
+                       .buf = &start,
+               },
+               {
+                       .addr = DRM_HDCP_DDC_ADDR,
+                       .flags = I2C_M_RD,
+                       .len = size,
+                       .buf = buffer
+               }
+       };
+       ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs));
+       if (ret == ARRAY_SIZE(msgs))
+               return 0;
+       return ret >= 0 ? -EIO : ret;
+}
+
+static int intel_hdmi_hdcp_write(struct intel_digital_port *intel_dig_port,
+                                unsigned int offset, void *buffer, size_t size)
+{
+       struct intel_hdmi *hdmi = &intel_dig_port->hdmi;
+       struct drm_i915_private *dev_priv =
+               intel_dig_port->base.base.dev->dev_private;
+       struct i2c_adapter *adapter = intel_gmbus_get_adapter(dev_priv,
+                                                             hdmi->ddc_bus);
+       int ret;
+       u8 *write_buf;
+       struct i2c_msg msg;
+
+       write_buf = kzalloc(size + 1, GFP_KERNEL);
+       if (!write_buf)
+               return -ENOMEM;
+
+       write_buf[0] = offset & 0xff;
+       memcpy(&write_buf[1], buffer, size);
+
+       msg.addr = DRM_HDCP_DDC_ADDR;
+       msg.flags = 0,
+       msg.len = size + 1,
+       msg.buf = write_buf;
+
+       ret = i2c_transfer(adapter, &msg, 1);
+       if (ret == 1)
+               return 0;
+       return ret >= 0 ? -EIO : ret;
+}
+
+static
+int intel_hdmi_hdcp_write_an_aksv(struct intel_digital_port *intel_dig_port,
+                                 u8 *an)
+{
+       struct intel_hdmi *hdmi = &intel_dig_port->hdmi;
+       struct drm_i915_private *dev_priv =
+               intel_dig_port->base.base.dev->dev_private;
+       struct i2c_adapter *adapter = intel_gmbus_get_adapter(dev_priv,
+                                                             hdmi->ddc_bus);
+       int ret;
+
+       ret = intel_hdmi_hdcp_write(intel_dig_port, DRM_HDCP_DDC_AN, an,
+                                   DRM_HDCP_AN_LEN);
+       if (ret) {
+               DRM_ERROR("Write An over DDC failed (%d)\n", ret);
+               return ret;
+       }
+
+       ret = intel_gmbus_output_aksv(adapter);
+       if (ret < 0) {
+               DRM_ERROR("Failed to output aksv (%d)\n", ret);
+               return ret;
+       }
+       return 0;
+}
+
+static int intel_hdmi_hdcp_read_bksv(struct intel_digital_port *intel_dig_port,
+                                    u8 *bksv)
+{
+       int ret;
+       ret = intel_hdmi_hdcp_read(intel_dig_port, DRM_HDCP_DDC_BKSV, bksv,
+                                  DRM_HDCP_KSV_LEN);
+       if (ret)
+               DRM_ERROR("Read Bksv over DDC failed (%d)\n", ret);
+       return ret;
+}
+
+static
+int intel_hdmi_hdcp_read_bstatus(struct intel_digital_port *intel_dig_port,
+                                u8 *bstatus)
+{
+       int ret;
+       ret = intel_hdmi_hdcp_read(intel_dig_port, DRM_HDCP_DDC_BSTATUS,
+                                  bstatus, DRM_HDCP_BSTATUS_LEN);
+       if (ret)
+               DRM_ERROR("Read bstatus over DDC failed (%d)\n", ret);
+       return ret;
+}
+
+static
+int intel_hdmi_hdcp_repeater_present(struct intel_digital_port *intel_dig_port,
+                                    bool *repeater_present)
+{
+       int ret;
+       u8 val;
+
+       ret = intel_hdmi_hdcp_read(intel_dig_port, DRM_HDCP_DDC_BCAPS, &val, 1);
+       if (ret) {
+               DRM_ERROR("Read bcaps over DDC failed (%d)\n", ret);
+               return ret;
+       }
+       *repeater_present = val & DRM_HDCP_DDC_BCAPS_REPEATER_PRESENT;
+       return 0;
+}
+
+static
+int intel_hdmi_hdcp_read_ri_prime(struct intel_digital_port *intel_dig_port,
+                                 u8 *ri_prime)
+{
+       int ret;
+       ret = intel_hdmi_hdcp_read(intel_dig_port, DRM_HDCP_DDC_RI_PRIME,
+                                  ri_prime, DRM_HDCP_RI_LEN);
+       if (ret)
+               DRM_ERROR("Read Ri' over DDC failed (%d)\n", ret);
+       return ret;
+}
+
+static
+int intel_hdmi_hdcp_read_ksv_ready(struct intel_digital_port *intel_dig_port,
+                                  bool *ksv_ready)
+{
+       int ret;
+       u8 val;
+
+       ret = intel_hdmi_hdcp_read(intel_dig_port, DRM_HDCP_DDC_BCAPS, &val, 1);
+       if (ret) {
+               DRM_ERROR("Read bcaps over DDC failed (%d)\n", ret);
+               return ret;
+       }
+       *ksv_ready = val & DRM_HDCP_DDC_BCAPS_KSV_FIFO_READY;
+       return 0;
+}
+
+static
+int intel_hdmi_hdcp_read_ksv_fifo(struct intel_digital_port *intel_dig_port,
+                                 int num_downstream, u8 *ksv_fifo)
+{
+       int ret;
+       ret = intel_hdmi_hdcp_read(intel_dig_port, DRM_HDCP_DDC_KSV_FIFO,
+                                  ksv_fifo, num_downstream * DRM_HDCP_KSV_LEN);
+       if (ret) {
+               DRM_ERROR("Read ksv fifo over DDC failed (%d)\n", ret);
+               return ret;
+       }
+       return 0;
+}
+
+static
+int intel_hdmi_hdcp_read_v_prime_part(struct intel_digital_port 
*intel_dig_port,
+                                     int i, u32 *part)
+{
+       int ret;
+
+       if (i >= DRM_HDCP_V_PRIME_NUM_PARTS)
+               return -EINVAL;
+
+       ret = intel_hdmi_hdcp_read(intel_dig_port, DRM_HDCP_DDC_V_PRIME(i),
+                                  part, DRM_HDCP_V_PRIME_PART_LEN);
+       if (ret)
+               DRM_ERROR("Read V'[%d] over DDC failed (%d)\n", i, ret);
+       return ret;
+}
+
+static
+int intel_hdmi_hdcp_toggle_signalling(struct intel_digital_port 
*intel_dig_port,
+                                     bool enable)
+{
+       int ret;
+       if (enable) {
+               ret = intel_ddi_enable_hdcp_signalling(&intel_dig_port->base);
+               if (ret) {
+                       DRM_ERROR("Enable HDCP signalling failed (%d)\n", ret);
+                       return ret;
+               }
+       } else {
+               usleep_range(6, 60); /* Bspec says >= 6us */
+               ret = intel_ddi_disable_hdcp_signalling(&intel_dig_port->base);
+               if (ret) {
+                       DRM_ERROR("Enable HDCP signalling failed (%d)\n", ret);
+                       return ret;
+               }
+       }
+       return 0;
+}
+
+static
+bool intel_hdmi_hdcp_check_link(struct intel_digital_port *intel_dig_port)
+{
+       struct drm_i915_private *dev_priv =
+               intel_dig_port->base.base.dev->dev_private;
+       enum port port = intel_dig_port->port;
+       int ret;
+       union {
+               u32 reg;
+               u8 shim[DRM_HDCP_RI_LEN];
+       } ri;
+
+       ret = intel_hdmi_hdcp_read_ri_prime(intel_dig_port, ri.shim);
+       if (ret)
+               return false;
+
+       I915_WRITE(SKL_PORT_HDCP_RPRIME(port), ri.reg);
+
+       // Wait for Ri prime match
+       if (wait_for(I915_READ(SKL_PORT_HDCP_STATUS(port)) &
+                    (SKL_HDCP_STATUS_RI_MATCH | SKL_HDCP_STATUS_ENC), 1)) {
+               DRM_ERROR("Ri' mismatch detected, link check failed (%x)\n",
+                         I915_READ(SKL_PORT_HDCP_STATUS(port)));
+               return false;
+       }
+       return true;
+}
+
+static const struct intel_hdcp_shim intel_hdmi_hdcp_shim = {
+       .write_an_aksv = intel_hdmi_hdcp_write_an_aksv,
+       .read_bksv = intel_hdmi_hdcp_read_bksv,
+       .read_bstatus = intel_hdmi_hdcp_read_bstatus,
+       .repeater_present = intel_hdmi_hdcp_repeater_present,
+       .read_ri_prime = intel_hdmi_hdcp_read_ri_prime,
+       .read_ksv_ready = intel_hdmi_hdcp_read_ksv_ready,
+       .read_ksv_fifo = intel_hdmi_hdcp_read_ksv_fifo,
+       .read_v_prime_part = intel_hdmi_hdcp_read_v_prime_part,
+       .toggle_signalling = intel_hdmi_hdcp_toggle_signalling,
+       .check_link = intel_hdmi_hdcp_check_link,
+};
+
  static void intel_hdmi_prepare(struct intel_encoder *encoder,
                               const struct intel_crtc_state *crtc_state)
  {
@@ -2039,6 +2286,12 @@ void intel_hdmi_init_connector(struct intel_digital_port 
*intel_dig_port,
intel_hdmi_add_properties(intel_hdmi, connector); + if (INTEL_GEN(dev_priv) >= 9) {
+               drm_connector_attach_content_protection_property(connector);
+               intel_connector->hdcp_shim = &intel_hdmi_hdcp_shim;
+               INIT_DELAYED_WORK(&intel_connector->hdcp_work, intel_hdcp_work);
+       }
+
        intel_connector_attach_encoder(intel_connector, intel_encoder);
        intel_hdmi->attached_connector = intel_connector;

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