On Tue, Sep 28, 2021 at 02:35:09PM -0700, abhinavk@xxxxxxxxxxxxxx wrote: > On 2021-09-28 11:02, Sean Paul wrote: > > On Tue, Sep 21, 2021 at 07:25:41PM -0700, abhinavk@xxxxxxxxxxxxxx wrote: > > > On 2021-09-15 13:38, Sean Paul wrote: > > > > From: Sean Paul <seanpaul@xxxxxxxxxxxx> > > > > > > > > This patch adds HDCP 1.x support to msm DP connectors using the new HDCP > > > > helpers. > > > > > > > > Cc: Stephen Boyd <swboyd@xxxxxxxxxxxx> > > > > Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx> > > > > Link: > > > > https://patchwork.freedesktop.org/patch/msgid/20210913175747.47456-15-sean@xxxxxxxxxx > > > > #v1 > > > > > > > > Changes in v2: > > > > -Squash [1] into this patch with the following changes (Stephen) > > > > -Update the sc7180 dtsi file > > > > -Remove resource names and just use index (Stephen) > > > > > > > > > > > > > > [1] > > > > https://patchwork.freedesktop.org/patch/msgid/20210913175747.47456-14-sean@xxxxxxxxxx > > > > --- > > > > /snip > > > > > > diff --git a/drivers/gpu/drm/msm/Makefile b/drivers/gpu/drm/msm/Makefile > > > > index 904535eda0c4..98731fd262d6 100644 > > > > --- a/drivers/gpu/drm/msm/Makefile > > > > +++ b/drivers/gpu/drm/msm/Makefile > > > > @@ -109,6 +109,7 @@ msm-$(CONFIG_DRM_MSM_DP)+= dp/dp_aux.o \ > > > > dp/dp_ctrl.o \ > > > > dp/dp_display.o \ > > > > dp/dp_drm.o \ > > > > + dp/dp_hdcp.o \ > > > > dp/dp_hpd.o \ > > > > dp/dp_link.o \ > > > > dp/dp_panel.o \ > > > > diff --git a/drivers/gpu/drm/msm/dp/dp_debug.c > > > > b/drivers/gpu/drm/msm/dp/dp_debug.c > > > > index 2f6247e80e9d..de16fca8782a 100644 > > > > --- a/drivers/gpu/drm/msm/dp/dp_debug.c > > > > +++ b/drivers/gpu/drm/msm/dp/dp_debug.c > > > > /snip > > > > > > +static ssize_t dp_hdcp_key_write(struct file *file, const char __user > > > > *ubuf, > > > > + size_t len, loff_t *offp) > > > > +{ > > > > + char *input_buffer; > > > > + int ret = 0; > > > > + struct dp_debug_private *debug = file->private_data; > > > > + struct drm_device *dev; > > > > + > > > > + dev = debug->drm_dev; > > > > + > > > > + if (len != (DRM_HDCP_KSV_LEN + DP_HDCP_NUM_KEYS * DP_HDCP_KEY_LEN)) > > > > + return -EINVAL; > > > > + > > > > + if (!debug->hdcp) > > > > + return -ENOENT; > > > > + > > > > + input_buffer = memdup_user_nul(ubuf, len); > > > > + if (IS_ERR(input_buffer)) > > > > + return PTR_ERR(input_buffer); > > > > + > > > > + ret = dp_hdcp_ingest_key(debug->hdcp, input_buffer, len); > > > > + > > > > + kfree(input_buffer); > > > > + if (ret < 0) { > > > > + DRM_ERROR("Could not ingest HDCP key, ret=%d\n", ret); > > > > + return ret; > > > > + } > > > > + > > > > + *offp += len; > > > > + return len; > > > > +} > > > > > > It seems like the HDCP keys written using debugfs, just for my > > > understanding, > > > are you storing this in some secure partition and the usermode reads > > > from it > > > and writes them here? > > > > > > > We have not sorted out the userspace side of HDCP enablement yet, so it > > remains > > to be seen whether the keys will be injected via debugfs/firmware > > file/property. > > > > /snip > > > > > > +static int dp_connector_atomic_check(struct drm_connector *connector, > > > > + struct drm_atomic_state *state) > > > > +{ > > > > + struct drm_connector_state *conn_state; > > > > + struct dp_connector_state *dp_state; > > > > + > > > > + conn_state = drm_atomic_get_new_connector_state(state, connector); > > > > + dp_state = to_dp_connector_state(conn_state); > > > > + > > > > + dp_state->hdcp_transition = drm_hdcp_atomic_check(connector, state); > > > > > > I have a general question related to the transition flag and overall > > > tying > > > the HDCP > > > enable and authentication to the commit. > > > So lets say there is a case where the driver needs to disable HDCP. > > > It could > > > be due > > > to link integrity failure OR some other error condition which > > > usermode is > > > not aware of. > > > In that case, we will set this hdcp_transition to true but in the next > > > commit we will > > > actually do the authentication. What if usermode doesnt issue a new > > > frame? > > > This question arises because currently the link intergrity check is > > > done > > > using SW polling > > > in the previous patchset. But as I had commented there, this occurs > > > in HW > > > for us. > > > I dont see that isr itself in this patchset. So wanted to understand > > > if > > > thats part of this > > > approach to still tie it with commit. > > > > > > So if we go with the HW polling based approach which is the preferred > > > method, we need to > > > untie this from the commit. > > > > > > > In the case of error, the worker will detect it and try to > > re-authenticate. If > > the re-authentication is successful, userspace will continue to be > > unaware and > > everything will keep working. If re-authentication is unsuccessful, the > > worker > > will update the property value and issue a uevent to userspace. So HDCP > > enablement is only tied to commits when the property value is changing > > as a > > result of userspace. > > > > Regarding SW vs HW link checks, I don't think there's any difference in > > efficacy > > between them. If HW can be relied on to issue an interrupt in failure > > cases, a > > follow-up set allowing for this seems like a great idea. > > > > Thanks for the explanation. Yes, from our experience it has been pretty > reliable to > issue signal integrity failures. We already had the isr based approach > downstream > and would prefer to keep it that way based on our experience of it firing > reliably. > We can still keep the SW polling code but it should come into effect only if > HW polling > is not supported / preferred. Ok, understood. Unfortunately I don't have access to a testing rig which could exercise the interrupt. Do you think you could post a follow-on patch to implement this? > > > > > + > > > > + return 0; > > > > +} > > > > /snip > > /snip > > > > +static int dp_hdcp_hdcp1_store_receiver_info(struct drm_connector > > > > *connector, > > > > + u32 *ksv, u32 status, u8 bcaps, > > > > + bool is_repeater) > > > > +{ > > > > + struct dp_hdcp *hdcp = dp_display_connector_to_hdcp(connector); > > > > + u32 val; > > > > + > > > > + dp_hdcp_write_tz(hdcp, HDCP_SEC_DP_TZ_HV_HLOS_HDCP_RCVPORT_DATA0, > > > > + ksv[0]); > > > > + dp_hdcp_write_tz(hdcp, HDCP_SEC_DP_TZ_HV_HLOS_HDCP_RCVPORT_DATA1, > > > > + ksv[1]); > > > > + > > > > + val = ((status & GENMASK(15, 0)) << 8) | (bcaps & GENMASK(7, 0)); > > > > + > > > > + dp_hdcp_write_tz(hdcp, HDCP_SEC_DP_TZ_HV_HLOS_HDCP_RCVPORT_DATA12, > > > > val); > > > > + > > > > > > Cant this entire API be skipped for non-repeater cases from the hdcp > > > lib > > > layer? > > > You can write the bcaps to this earlier and write the bstatus only > > > if its a > > > repeater. > > > > Could you expand on the benefits of this? > > We can avoid the call coming into the vendor driver hook itself as it need > not be called > for non-repeater cases. So something like this can be done in the HDCP lib? > > if ( repeater && ops->hdcp1_store_receiver_info ) > ops->hdcp1_store_receiver_info(....); > Unfortunately this would break Intel's implementation. > > > > > > > > > + return 0; > > > > +} > > > > /snip -- Sean Paul, Software Engineer, Google / Chromium OS
