On Sat, Feb 03, 2018 at 01:41:34AM +0530, Ramalingam C wrote:
> DP HDCP1.4 spec mandates that An can be written to panel only after
> detecting the panel's hdcp capability.
>
> For DP 0th Bit of Bcaps register indicates the panel's hdcp capability
> For HDMI valid BKSV indicates the panel's hdcp capability.
>
> For HDMI it is optional to detect the panel's hdcp capability before
> An Write.
>
> v2:
> Added comments explaining the need for action [Seanpaul].
> Made panel's hdcp capability detection optional for hdmi [Seanpaul].
> Defined a func for reading bcaps for DP [Seanpaul].
>
> Signed-off-by: Ramalingam C <ramalinga...@intel.com>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 39
> +++++++++++++++++++++++++++++++++++----
> drivers/gpu/drm/i915/intel_drv.h | 4 ++++
> drivers/gpu/drm/i915/intel_hdcp.c | 18 +++++++++++++++++-
> drivers/gpu/drm/i915/intel_hdmi.c | 1 +
> 4 files changed, 57 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 03d86ff9b805..5fa6bb7dbb7a 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -5107,17 +5107,32 @@ static int intel_dp_hdcp_read_bstatus(struct
> intel_digital_port *intel_dig_port,
> }
>
> static
> -int intel_dp_hdcp_repeater_present(struct intel_digital_port *intel_dig_port,
> - bool *repeater_present)
> +int intel_dp_hdcp_read_bcaps(struct intel_digital_port *intel_dig_port,
> + u8 *bcaps)
> {
> ssize_t ret;
> - u8 bcaps;
> +
> ret = drm_dp_dpcd_read(&intel_dig_port->dp.aux, DP_AUX_HDCP_BCAPS,
> - &bcaps, 1);
> + bcaps, 1);
> if (ret != 1) {
> DRM_ERROR("Read bcaps from DP/AUX failed (%zd)\n", ret);
> return ret >= 0 ? -EIO : ret;
> }
> +
> + return 0;
> +}
> +
> +static
> +int intel_dp_hdcp_repeater_present(struct intel_digital_port *intel_dig_port,
> + bool *repeater_present)
> +{
> + ssize_t ret;
> + u8 bcaps;
> +
> + ret = intel_dp_hdcp_read_bcaps(intel_dig_port, &bcaps);
> + if (ret)
> + return ret;
> +
> *repeater_present = bcaps & DP_BCAPS_REPEATER_PRESENT;
> return 0;
> }
> @@ -5218,6 +5233,21 @@ bool intel_dp_hdcp_check_link(struct
> intel_digital_port *intel_dig_port)
> return !(bstatus & (DP_BSTATUS_LINK_FAILURE | DP_BSTATUS_REAUTH_REQ));
> }
>
> +static
> +int intel_dp_hdcp_capable(struct intel_digital_port *intel_dig_port,
> + bool *hdcp_capable)
> +{
> + ssize_t ret;
> + u8 bcaps;
> +
> + ret = intel_dp_hdcp_read_bcaps(intel_dig_port, &bcaps);
> + if (ret)
> + return ret;
> +
> + *hdcp_capable = bcaps & DP_BCAPS_HDCP_CAPABLE;
> + return 0;
> +}
> +
> static const struct intel_hdcp_shim intel_dp_hdcp_shim = {
> .write_an_aksv = intel_dp_hdcp_write_an_aksv,
> .read_bksv = intel_dp_hdcp_read_bksv,
> @@ -5229,6 +5259,7 @@ static const struct intel_hdcp_shim intel_dp_hdcp_shim
> = {
> .read_v_prime_part = intel_dp_hdcp_read_v_prime_part,
> .toggle_signalling = intel_dp_hdcp_toggle_signalling,
> .check_link = intel_dp_hdcp_check_link,
> + .hdcp_capable = intel_dp_hdcp_capable,
> };
>
> static void intel_edp_panel_vdd_sanitize(struct intel_dp *intel_dp)
> diff --git a/drivers/gpu/drm/i915/intel_drv.h
> b/drivers/gpu/drm/i915/intel_drv.h
> index d6a808374dfb..468ec1e90e16 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -369,6 +369,10 @@ struct intel_hdcp_shim {
>
> /* Ensures the link is still protected */
> bool (*check_link)(struct intel_digital_port *intel_dig_port);
> +
> + /* Detects panel's hdcp capability. This is optional for HDMI. */
> + int (*hdcp_capable)(struct intel_digital_port *intel_dig_port,
> + bool *hdcp_capable);
> };
>
> struct intel_connector {
> diff --git a/drivers/gpu/drm/i915/intel_hdcp.c
> b/drivers/gpu/drm/i915/intel_hdcp.c
> index 0cee79c86d7e..4b2821feb4b4 100644
> --- a/drivers/gpu/drm/i915/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/intel_hdcp.c
> @@ -414,12 +414,28 @@ static int intel_hdcp_auth(struct intel_digital_port
> *intel_dig_port,
> u32 reg;
> u8 shim[DRM_HDCP_RI_LEN];
> } ri;
> - bool repeater_present;
> + bool repeater_present, hdcp_capable;
>
> dev_priv = intel_dig_port->base.base.dev->dev_private;
>
> port = intel_dig_port->base.port;
>
> + /*
> + * Detects whether the display is HDCP capable. Although we check for
> + * valid Bksv below, the HDCP over DP spec requires that we check
> + * whether the display supports HDCP before we write An. For HDMI
> + * displays, this is not necessary.
> + */
> + if (shim->hdcp_capable) {
> + ret = shim->hdcp_capable(intel_dig_port, &hdcp_capable);
> + if (ret)
> + return ret;
> + if (!hdcp_capable) {
> + DRM_ERROR("Panel is not HDCP capable\n");
> + return -EINVAL;
> + }
> + }
> +
> /* Initialize An with 2 random values and acquire it */
> for (i = 0; i < 2; i++)
> I915_WRITE(PORT_HDCP_ANINIT(port), get_random_u32());
> diff --git a/drivers/gpu/drm/i915/intel_hdmi.c
> b/drivers/gpu/drm/i915/intel_hdmi.c
> index f5d7bfb43006..1a05a4bf442e 100644
> --- a/drivers/gpu/drm/i915/intel_hdmi.c
> +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> @@ -1117,6 +1117,7 @@ static const struct intel_hdcp_shim
> intel_hdmi_hdcp_shim = {
> .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,
> + .hdcp_capable = NULL,
nit: This isn't needed, it will already be initialized to NULL.
With that fixed:
Reviewed-by: Sean Paul <seanp...@chromium.org>
> };
>
> static void intel_hdmi_prepare(struct intel_encoder *encoder,
> --
> 2.7.4
>
--
Sean Paul, Software Engineer, Google / Chromium OS
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