[RFC PATCH 6/6] drm/i915: Implement HDCP for DisplayPort

Sean Paul
2017-11-30T03:10:24Z

This patch adds HDCP support for DisplayPort connectors by implementing
the intel_hdcp_shim.

Most of this is straightforward read/write from/to DPCD registers. One
thing worth pointing out is the Aksv output bit. It wasn't easily
separable like it's HDMI counterpart, so it's crammed in with the rest
of it.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
---
drivers/gpu/drm/i915/intel_dp.c | 243 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 236 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index d11281004109..091c8bcc4645 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -36,7 +36,9 @@
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc.h>
#include <drm/drm_crtc_helper.h>
+#include <drm/drm_dp_helper.h>
#include <drm/drm_edid.h>
+#include <drm/drm_hdcp.h>
#include "intel_drv.h"
#include <drm/i915_drm.h>
#include "i915_drv.h"
@@ -1039,10 +1041,29 @@ static uint32_t skl_get_aux_send_ctl(struct intel_dp *intel_dp,
DP_AUX_CH_CTL_SYNC_PULSE_SKL(32);
}

+static uint32_t intel_dp_get_aux_send_ctl(struct intel_dp *intel_dp,
+ bool has_aux_irq,
+ int send_bytes,
+ uint32_t aux_clock_divider,
+ bool aksv_write)
+{
+ uint32_t val = 0;
+
+ if (aksv_write) {
+ send_bytes += 5;
+ val |= DP_AUX_CH_CTL_AUX_AKSV_SELECT;
+ }
+
+ return val | intel_dp->get_aux_send_ctl(intel_dp,
+ has_aux_irq,
+ send_bytes,
+ aux_clock_divider);
+}
+
static int
intel_dp_aux_ch(struct intel_dp *intel_dp,
const uint8_t *send, int send_bytes,
- uint8_t *recv, int recv_size)
+ uint8_t *recv, int recv_size, bool aksv_write)
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
struct drm_i915_private *dev_priv =
@@ -1102,10 +1123,11 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
}

while ((aux_clock_divider = intel_dp->get_aux_clock_divider(intel_dp, clock++))) {
- u32 send_ctl = intel_dp->get_aux_send_ctl(intel_dp,
- has_aux_irq,
- send_bytes,
- aux_clock_divider);
+ u32 send_ctl = intel_dp_get_aux_send_ctl(intel_dp,
+ has_aux_irq,
+ send_bytes,
+ aux_clock_divider,
+ aksv_write);

/* Must try at least 3 times according to DP spec */
for (try = 0; try < 5; try++) {
@@ -1242,7 +1264,8 @@ intel_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
if (msg->buffer)
memcpy(txbuf + HEADER_SIZE, msg->buffer, msg->size);

- ret = intel_dp_aux_ch(intel_dp, txbuf, txsize, rxbuf, rxsize);
+ ret = intel_dp_aux_ch(intel_dp, txbuf, txsize, rxbuf, rxsize,
+ false);
if (ret > 0) {
msg->reply = rxbuf[0] >> 4;

@@ -1264,7 +1287,8 @@ intel_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
if (WARN_ON(rxsize > 20))
return -E2BIG;

- ret = intel_dp_aux_ch(intel_dp, txbuf, txsize, rxbuf, rxsize);
+ ret = intel_dp_aux_ch(intel_dp, txbuf, txsize, rxbuf, rxsize,
+ false);
if (ret > 0) {
msg->reply = rxbuf[0] >> 4;
/*
@@ -4310,6 +4334,8 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)

intel_dp_retrain_link(intel_dp);
}
+
+ intel_hdcp_check_link(intel_dp->attached_connector);
}

/*
@@ -4977,6 +5003,203 @@ void intel_dp_encoder_suspend(struct intel_encoder *intel_encoder)
pps_unlock(intel_dp);
}

+static
+int intel_dp_hdcp_write_an_aksv(struct intel_digital_port *intel_dig_port,
+ u8 *an)
+{
+ struct intel_dp *intel_dp = enc_to_intel_dp(&intel_dig_port->base.base);
+ uint8_t txbuf[4], rxbuf[2], reply = 0;
+ ssize_t dpcd_ret;
+ int ret;
+
+ /* Output An first, that's easy */
+ dpcd_ret = drm_dp_dpcd_write(&intel_dig_port->dp.aux, DP_AUX_HDCP_AN,
+ an, DRM_HDCP_AN_LEN);
+ if (dpcd_ret != DRM_HDCP_AN_LEN) {
+ DRM_ERROR("Failed to write An over DP/AUX (%ld)\n", dpcd_ret);
+ return dpcd_ret >= 0 ? -EIO : dpcd_ret;
+ }
+
+ /*
+ * Since Aksv is Oh-So-Secret, we can't access it in software. So in
+ * order to get it on the wire, we need to create the AUX header as if
+ * we were writing the data, and then tickle the hardware to output the
+ * data once the header is sent out.
+ */
+ txbuf[0] = (DP_AUX_NATIVE_WRITE << 4) |
+ ((DP_AUX_HDCP_AKSV >> 16) & 0xf);
+ txbuf[1] = (DP_AUX_HDCP_AKSV >> 8) & 0xff;
+ txbuf[2] = DP_AUX_HDCP_AKSV & 0xff;
+ txbuf[3] = DRM_HDCP_KSV_LEN - 1;
+
+ ret = intel_dp_aux_ch(intel_dp, txbuf, sizeof(txbuf), rxbuf,
+ sizeof(rxbuf), true);
+ if (ret < 0) {
+ DRM_ERROR("Write Aksv over DP/AUX failed (%d)\n", ret);
+ return ret;
+ } else if (ret == 0) {
+ DRM_ERROR("Aksv write over DP/AUX was empty\n");
+ return -EIO;
+ }
+
+ reply = (rxbuf[0] >> 4) & DP_AUX_NATIVE_REPLY_MASK;
+ return reply == DP_AUX_NATIVE_REPLY_ACK ? 0 : -EIO;
+}
+
+static int intel_dp_hdcp_read_bksv(struct intel_digital_port *intel_dig_port,
+ u8 *bksv)
+{
+ ssize_t ret;
+ ret = drm_dp_dpcd_read(&intel_dig_port->dp.aux, DP_AUX_HDCP_BKSV, bksv,
+ DRM_HDCP_KSV_LEN);
+ if (ret != DRM_HDCP_KSV_LEN) {
+ DRM_ERROR("Read Bksv from DP/AUX failed (%ld)\n", ret);
+ return ret >= 0 ? -EIO : ret;
+ }
+ return 0;
+}
+
+static int intel_dp_hdcp_read_bstatus(struct intel_digital_port *intel_dig_port,
+ u8 *bstatus)
+{
+ ssize_t ret;
+ /*
+ * For some reason the HDMI and DP HDCP specs call this register
+ * definition by different names. In the HDMI spec, it's called BSTATUS,
+ * but in DP it's called BINFO.
+ */
+ ret = drm_dp_dpcd_read(&intel_dig_port->dp.aux, DP_AUX_HDCP_BINFO,
+ bstatus, DRM_HDCP_BSTATUS_LEN);
+ if (ret != DRM_HDCP_BSTATUS_LEN) {
+ DRM_ERROR("Read bstatus from DP/AUX failed (%ld)\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 = drm_dp_dpcd_read(&intel_dig_port->dp.aux, DP_AUX_HDCP_BCAPS,
+ &bcaps, 1);
+ if (ret != 1) {
+ DRM_ERROR("Read bcaps from DP/AUX failed (%ld)\n", ret);
+ return ret >= 0 ? -EIO : ret;
+ }
+ *repeater_present = bcaps & DP_BCAPS_REPEATER_PRESENT;
+ return 0;
+}
+
+static
+int intel_dp_hdcp_read_ri_prime(struct intel_digital_port *intel_dig_port,
+ u8 *ri_prime)
+{
+ ssize_t ret;
+ ret = drm_dp_dpcd_read(&intel_dig_port->dp.aux, DP_AUX_HDCP_RI_PRIME,
+ ri_prime, DRM_HDCP_RI_LEN);
+ if (ret != DRM_HDCP_RI_LEN) {
+ DRM_ERROR("Read Ri' from DP/AUX failed (%ld)\n", ret);
+ return ret >= 0 ? -EIO : ret;
+ }
+ return 0;
+}
+
+static
+int intel_dp_hdcp_read_ksv_ready(struct intel_digital_port *intel_dig_port,
+ bool *ksv_ready)
+{
+ ssize_t ret;
+ u8 bstatus;
+ ret = drm_dp_dpcd_read(&intel_dig_port->dp.aux, DP_AUX_HDCP_BSTATUS,
+ &bstatus, 1);
+ if (ret != 1) {
+ DRM_ERROR("Read bstatus from DP/AUX failed (%ld)\n", ret);
+ return ret >= 0 ? -EIO : ret;
+ }
+ *ksv_ready = bstatus & DP_BSTATUS_READY;
+ return 0;
+}
+
+static
+int intel_dp_hdcp_read_ksv_fifo(struct intel_digital_port *intel_dig_port,
+ int num_downstream, u8 *ksv_fifo)
+{
+ ssize_t ret;
+ int i;
+
+ // KSV list is read via 15 byte window (3 entries @ 5 bytes each)
+ for (i = 0; i < num_downstream; i += 3) {
+ size_t len = min(num_downstream - i, 3) * DRM_HDCP_KSV_LEN;
+ ret = drm_dp_dpcd_read(&intel_dig_port->dp.aux,
+ DP_AUX_HDCP_KSV_FIFO,
+ ksv_fifo + i * DRM_HDCP_KSV_LEN,
+ len);
+ if (ret != len) {
+ DRM_ERROR("Read ksv[%d] from DP/AUX failed (%ld)\n", i,
+ ret);
+ return ret >= 0 ? -EIO : ret;
+ }
+ }
+ return 0;
+}
+
+static
+int intel_dp_hdcp_read_v_prime_part(struct intel_digital_port *intel_dig_port,
+ int i, u32 *part)
+{
+ ssize_t ret;
+
+ if (i >= DRM_HDCP_V_PRIME_NUM_PARTS)
+ return -EINVAL;
+
+ ret = drm_dp_dpcd_read(&intel_dig_port->dp.aux,
+ DP_AUX_HDCP_V_PRIME(i), part,
+ DRM_HDCP_V_PRIME_PART_LEN);
+ if (ret != DRM_HDCP_V_PRIME_PART_LEN) {
+ DRM_ERROR("Read v'[%d] from DP/AUX failed (%ld)\n", i, ret);
+ return ret >= 0 ? -EIO : ret;
+ }
+ return 0;
+}
+
+static
+int intel_dp_hdcp_toggle_signalling(struct intel_digital_port *intel_dig_port,
+ bool enable)
+{
+ /* Not used for single stream DisplayPort setups */
+ return 0;
+}
+
+static
+bool intel_dp_hdcp_check_link(struct intel_digital_port *intel_dig_port)
+{
+ ssize_t ret;
+ u8 bstatus;
+ ret = drm_dp_dpcd_read(&intel_dig_port->dp.aux, DP_AUX_HDCP_BSTATUS,
+ &bstatus, 1);
+ if (ret != 1) {
+ DRM_ERROR("Read bstatus from DP/AUX failed (%ld)\n", ret);
+ return ret >= 0 ? -EIO : ret;
+ }
+ return !(bstatus & DP_BSTATUS_LINK_FAILURE);
+}
+
+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,
+ .read_bstatus = intel_dp_hdcp_read_bstatus,
+ .repeater_present = intel_dp_hdcp_repeater_present,
+ .read_ri_prime = intel_dp_hdcp_read_ri_prime,
+ .read_ksv_ready = intel_dp_hdcp_read_ksv_ready,
+ .read_ksv_fifo = intel_dp_hdcp_read_ksv_fifo,
+ .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,
+};
+
static void intel_edp_panel_vdd_sanitize(struct intel_dp *intel_dp)
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
@@ -6097,6 +6320,12 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,

intel_dp_add_properties(intel_dp, connector);

+ if (INTEL_GEN(dev_priv) >= 9 && !intel_dp_is_edp(intel_dp)) {
+ drm_connector_attach_content_protection_property(connector);
+ intel_connector->hdcp_shim = &intel_dp_hdcp_shim;
+ INIT_DELAYED_WORK(&intel_connector->hdcp_work, intel_hdcp_work);
+ }
+
/* For G4X desktop chip, PEG_BAND_GAP_DATA 3:0 must first be written
* 0xd. Failure to do so will result in spurious interrupts being
* generated on the port when a cable is not attached.
--
2.15.0.531.g2ccb3012c9-goog