On Tue, Sep 28, 2021 at 02:35:09PM -0700, abhinavk@codeaurora.org wrote:
On 2021-09-28 11:02, Sean Paul wrote:
On Tue, Sep 21, 2021 at 07:25:41PM -0700, abhinavk@codeaurora.org wrote:
On 2021-09-15 13:38, Sean Paul wrote:
From: Sean Paul seanpaul@chromium.org
This patch adds HDCP 1.x support to msm DP connectors using the new HDCP helpers.
Cc: Stephen Boyd swboyd@chromium.org Signed-off-by: Sean Paul seanpaul@chromium.org Link: https://patchwork.freedesktop.org/patch/msgid/20210913175747.47456-15-sean@p... #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@p...
/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