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.
> +
> + return 0;
> +}
/snip
> +static int dp_hdcp_load_keys(struct drm_connector *connector)
> +{
> + struct dp_hdcp *hdcp = dp_display_connector_to_hdcp(connector);
> + struct dp_hdcp_key *key;
> + int i, ret = 0;
> +
> + mutex_lock(&hdcp->key_lock);
> +
> + key = hdcp->key;
> +
> + if (!key->valid) {
> + ret = -ENOENT;
> + goto out;
> + }
> +
> + dp_hdcp_write_dp(hdcp, DP_HDCP_SW_LOWER_AKSV, key->ksv.words[0]);
> + dp_hdcp_write_dp(hdcp, DP_HDCP_SW_UPPER_AKSV, key->ksv.words[1]);
> +
> + for (i = 0; i < DP_HDCP_NUM_KEYS; i++) {
> + dp_hdcp_write_hdcp(hdcp, DP_HDCP_KEY_LSB(i),
> + key->keys[i].words[0]);
> + dp_hdcp_write_hdcp(hdcp, DP_HDCP_KEY_MSB(i),
> + key->keys[i].words[1]);
> + }
> +
> + dp_hdcp_write_hdcp(hdcp, DP_HDCP_KEY_VALID, DP_HDCP_SW_KEY_VALID);
I think all of these are TZ_*** registers. So the separation of
write_hdcp()
Vs write_hdcp_tz()
is not very clear to me.
Maybe change the write APIs to something like dp_hdcp_write_hdcp_tz()
for
the first address space
and dp_hdcp_write_hdcp_tz_hlos() for the other one?
Will do in v3, thank you for the suggestion.
> + wmb();
> +
> + dp_hdcp_write_dp(hdcp, DP_HDCP_ENTROPY_CTRL0, get_random_u32());
> + dp_hdcp_write_dp(hdcp, DP_HDCP_ENTROPY_CTRL1, get_random_u32());
> + wmb();
> +
> +out:
> + mutex_unlock(&hdcp->key_lock);
> + return ret;
> +}
> +
> +static int dp_hdcp_hdcp2_capable(struct drm_connector *connector,
> bool *capable)
> +{
> + *capable = false;
> + return 0;
> +}
> +
> +static int dp_hdcp_hdcp1_read_an_aksv(struct drm_connector *connector,
> + u32 *an, u32 *aksv)
> +{
> + struct dp_hdcp *hdcp = dp_display_connector_to_hdcp(connector);
> + bool keys_valid;
> + int ret;
> + u32 val;
> +
> + dp_hdcp_write_dp(hdcp, DP_HDCP_CTRL, 1);
> +
> + ret = read_poll_timeout(dp_hdcp_are_keys_valid, keys_valid,
> keys_valid,
> + 20 * 1000, 10 * 1000, false, connector);
> + if (ret) {
> + drm_err(hdcp->dev, "HDCP keys invalid %d\n", ret);
> + return ret;
> + }
> +
> + /* Clear AInfo */
> + dp_hdcp_write_dp(hdcp, DP_HDCP_RCVPORT_DATA4, 0);
> +
> + aksv[0] = dp_hdcp_read_dp(hdcp, DP_HDCP_RCVPORT_DATA3);
> + aksv[1] = GENMASK(7, 0) & dp_hdcp_read_dp(hdcp,
> DP_HDCP_RCVPORT_DATA4);
> +
> + ret = read_poll_timeout(dp_hdcp_read_dp, val,
> + (val & DP_HDCP_AN_READY_MASK) == DP_HDCP_AN_READY_MASK,
> + 100, 10 * 1000, false, hdcp, DP_HDCP_STATUS);
> + if (ret) {
> + drm_err(hdcp->dev, "AN failed to become ready %x/%d\n", val, ret);
> + return ret;
> + }
> +
> + /*
> + * Get An from hardware, for unknown reasons we need to read the reg
> + * twice to get valid data.
> + */
> + dp_hdcp_read_dp(hdcp, DP_HDCP_RCVPORT_DATA5);
> + an[0] = dp_hdcp_read_dp(hdcp, DP_HDCP_RCVPORT_DATA5);
> +
> + dp_hdcp_read_dp(hdcp, DP_HDCP_RCVPORT_DATA6);
> + an[1] = dp_hdcp_read_dp(hdcp, DP_HDCP_RCVPORT_DATA6);
Yes its true, but we also have a 1 microsec delay between the first
and
second one.
So I would certainly preserve that.
Will do in v3, thank you for the suggestion.
> +
> + return 0;
> +}
> +
> +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?
