Re: [RFC PATCH 5/6] drm/i915: Implement HDCP for HDMI

Ramalingam C
2017-12-01T07:35:55Z

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 <seanpaul@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;
>