[PATCH v8 08/35] drm/i915: Implement HDCP2.2 repeater authentication
Daniel Vetter
daniel at ffwll.ch
Thu Dec 6 10:45:49 UTC 2018
On Tue, Nov 27, 2018 at 04:13:06PM +0530, Ramalingam C wrote:
> Implements the HDCP2.2 repeaters authentication steps such as verifying
> the downstream topology and sending stream management information.
>
> v2:
> Rebased.
> v3:
> No Changes.
> v4:
> -EINVAL is returned for topology error and rollover scenario.
> Endianness conversion func from drm_hdcp.h is used [Uma]
> v5:
> Rebased as part of patches reordering.
> Defined the mei service functions [Daniel]
> v6:
> Redefined the mei service functions as per comp redesign.
> v7:
> %s/uintxx_t/uxx
> Check for comp_master is removed.
> v8:
> Adjust to the new mei interface.
> style issue fixed.
>
> Signed-off-by: Ramalingam C <ramalingam.c at intel.com>
> ---
> drivers/gpu/drm/i915/intel_hdcp.c | 125 +++++++++++++++++++++++++++++++++++++-
> include/drm/drm_hdcp.h | 15 +++++
> 2 files changed, 138 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_hdcp.c b/drivers/gpu/drm/i915/intel_hdcp.c
> index 0d7fea9c9bb1..679f3c164582 100644
> --- a/drivers/gpu/drm/i915/intel_hdcp.c
> +++ b/drivers/gpu/drm/i915/intel_hdcp.c
> @@ -1069,7 +1069,7 @@ static int hdcp2_prepare_skey(struct intel_connector *connector,
> return ret;
> }
>
> -static __attribute__((unused)) int
> +static int
> hdcp2_verify_rep_topology_prepare_ack(struct intel_connector *connector,
> struct hdcp2_rep_send_receiverid_list
> *rep_topology,
> @@ -1099,7 +1099,7 @@ hdcp2_verify_rep_topology_prepare_ack(struct intel_connector *connector,
> return ret;
> }
>
> -static __attribute__((unused)) int
> +static int
> hdcp2_verify_mprime(struct intel_connector *connector,
> struct hdcp2_rep_stream_ready *stream_ready)
> {
> @@ -1315,6 +1315,121 @@ static int hdcp2_session_key_exchange(struct intel_connector *connector)
> return 0;
> }
>
> +static
> +int hdcp2_propagate_stream_management_info(struct intel_connector *connector)
> +{
> + struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
> + struct intel_hdcp *hdcp = &connector->hdcp;
> + union {
> + struct hdcp2_rep_stream_manage stream_manage;
> + struct hdcp2_rep_stream_ready stream_ready;
> + } msgs;
> + const struct intel_hdcp_shim *shim = hdcp->shim;
> + int ret;
> +
> + /* Prepare RepeaterAuth_Stream_Manage msg */
> + msgs.stream_manage.msg_id = HDCP_2_2_REP_STREAM_MANAGE;
> + reverse_endianness(msgs.stream_manage.seq_num_m, HDCP_2_2_SEQ_NUM_LEN,
> + (u8 *)&hdcp->seq_num_m);
> +
> + /* K no of streams is fixed as 1. Stored as big-endian. */
> + msgs.stream_manage.k = __swab16(1);
> +
> + /* For HDMI this is forced to be 0x0. For DP SST also this is 0x0. */
> + msgs.stream_manage.streams[0].stream_id = 0;
> + msgs.stream_manage.streams[0].stream_type = hdcp->content_type;
> +
> + /* Send it to Repeater */
> + ret = shim->write_2_2_msg(intel_dig_port, &msgs.stream_manage,
> + sizeof(msgs.stream_manage));
> + if (ret < 0)
> + return ret;
> +
> + ret = shim->read_2_2_msg(intel_dig_port, HDCP_2_2_REP_STREAM_READY,
> + &msgs.stream_ready, sizeof(msgs.stream_ready));
> + if (ret < 0)
> + return ret;
> +
> + hdcp->mei_data.seq_num_m = hdcp->seq_num_m;
> + hdcp->mei_data.streams[0].stream_type = hdcp->content_type;
> +
> + ret = hdcp2_verify_mprime(connector, &msgs.stream_ready);
> + if (ret < 0)
> + return ret;
> +
> + hdcp->seq_num_m++;
> +
> + if (hdcp->seq_num_m > HDCP_2_2_SEQ_NUM_MAX) {
> + DRM_DEBUG_KMS("seq_num_m roll over.\n");
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> +static
> +int hdcp2_authenticate_repeater_topology(struct intel_connector *connector)
> +{
> + struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
> + struct intel_hdcp *hdcp = &connector->hdcp;
> + union {
> + struct hdcp2_rep_send_receiverid_list recvid_list;
> + struct hdcp2_rep_send_ack rep_ack;
> + } msgs;
> + const struct intel_hdcp_shim *shim = hdcp->shim;
> + u8 *rx_info;
> + u32 seq_num_v;
> + int ret;
> +
> + ret = shim->read_2_2_msg(intel_dig_port, HDCP_2_2_REP_SEND_RECVID_LIST,
> + &msgs.recvid_list, sizeof(msgs.recvid_list));
> + if (ret < 0)
> + return ret;
> +
> + rx_info = msgs.recvid_list.rx_info;
> +
> + if (HDCP_2_2_MAX_CASCADE_EXCEEDED(rx_info[1]) ||
> + HDCP_2_2_MAX_DEVS_EXCEEDED(rx_info[1])) {
> + DRM_DEBUG_KMS("Topology Max Size Exceeded\n");
> + return -EINVAL;
> + }
> +
> + /* Converting and Storing the seq_num_v to local variable as DWORD */
> + reverse_endianness((u8 *)&seq_num_v, HDCP_2_2_SEQ_NUM_LEN,
> + msgs.recvid_list.seq_num_v);
> +
> + if (seq_num_v < hdcp->seq_num_v) {
> + /* Roll over of the seq_num_v from repeater. Reauthenticate. */
> + DRM_DEBUG_KMS("Seq_num_v roll over.\n");
> + return -EINVAL;
> + }
> +
> + ret = hdcp2_verify_rep_topology_prepare_ack(connector,
> + &msgs.recvid_list,
> + &msgs.rep_ack);
> + if (ret < 0)
> + return ret;
> +
> + hdcp->seq_num_v = seq_num_v;
> + ret = shim->write_2_2_msg(intel_dig_port, &msgs.rep_ack,
> + sizeof(msgs.rep_ack));
> + if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> +static int hdcp2_authenticate_repeater(struct intel_connector *connector)
> +{
> + int ret;
> +
> + ret = hdcp2_authenticate_repeater_topology(connector);
> + if (ret < 0)
> + return ret;
> +
> + return hdcp2_propagate_stream_management_info(connector);
> +}
> +
> static int hdcp2_authenticate_sink(struct intel_connector *connector)
> {
> struct intel_digital_port *intel_dig_port = conn_to_dig_port(connector);
> @@ -1356,6 +1471,12 @@ static int hdcp2_authenticate_sink(struct intel_connector *connector)
> sizeof(stream_type_msg));
> if (ret < 0)
> return ret;
> + } else if (hdcp->is_repeater) {
> + ret = hdcp2_authenticate_repeater(connector);
> + if (ret < 0) {
> + DRM_DEBUG_KMS("Repeater Auth Failed. Err: %d\n", ret);
> + return ret;
> + }
> }
>
> hdcp->mei_data.streams[0].stream_type = hdcp->content_type;
> diff --git a/include/drm/drm_hdcp.h b/include/drm/drm_hdcp.h
> index a6de09c5e47f..3e45a7618ab3 100644
> --- a/include/drm/drm_hdcp.h
> +++ b/include/drm/drm_hdcp.h
> @@ -250,4 +250,19 @@ struct hdcp2_dp_errata_stream_type {
> #define HDCP_2_2_HDMI_RXSTATUS_READY(x) ((x) & BIT(2))
> #define HDCP_2_2_HDMI_RXSTATUS_REAUTH_REQ(x) ((x) & BIT(3))
>
> +/*
> + * Library functions for endianness are aligned for 16/32/64 bits.
> + * But hdcp sequence numbers are 24bits. So for their Byte swapping,
> + * a conversion function is developed.
> + */
> +static inline void reverse_endianness(u8 *dest, size_t sz, u8 *src)
This feels a bit fake-generic and doesn't fit that well into what you want
it to do in the code actually. What about:
u32 drm_hdcp2_seq_num_to_u32(u8 seq_num[HDCP_2_2_SEQ_NUM_LEN])
{
return seq_num[2] | seq_num[1] << 8 | seq_num[0] << 16;
}
(I didn't check the math).
I think this would both make the code more clearer and avoid the problem
of "shouldn't we make sure this works for everything and put it into
linux/string.h?"
Again I'll check the actual hdcp2 flow later on.
In general I'm kinda not happy with the shim midlayer design, but I wasn't
happy with that with hdcp1 either, and hdcp2 is just an extension, and I
don't really have a better idea either so seems all good to me.
-Daniel
> +{
> + u32 index;
> +
> + if (!sz || sz > sizeof(u32))
> + return;
> + for (index = 0; index < sz; index++)
> + dest[sz - index - 1] = src[index];
> +}
> +
> #endif
> --
> 2.7.4
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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